Abstract Volume7th Swiss Geoscience MeetingNeuchâtel, 20th – 21st November 2009

Table of contents

Organisation 3

Abstracts

0. Plenary Session 4

1. Water across (scientific) boundaries 10

2. Structural Geology, Tectonics and Geodynamics 58

3. Mineralogy-Petrology-Geochemistry 116

4. Open Cryosphere session 164

5. Meteorology and climatology 188

6. Darwin, Evolution and Palaeontology 198

7. Future horizons in marine and continental research drilling 214

8. Geoscience and Geoinformation – From data acquisition to modelling and visualisation 226

9. Water and land resources in developing countries: towards innovative management and governance 262

10. Processes and environments influenced by water – boundaries crossed and encountered in the Quaternary research + Biological, physical and chemical processes in soils 274

11. Decision oriented modelling of the geosphere 304

7th Swiss Geoscience Meeting, Neuchâtel 2009

http://geoscience-meeting.scnatweb.ch

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Host Institution

Centre of Hydrogeology of the University of Neuchâtel (Chyn)

Patronnage

Platform Geosciences, Swiss Academy of Sciences

Program Committee

Daniel Ariztegui Ronald Kozel

Peter Baumgartner Neil Mancktelow

Judit Becze-Deak Franziska Nyffenegger

Gilles Borel Nils Oesterling

Thomas Breu Adrian Pfiffner

Lionel Cavin Marcel Pfiffner

Pierre Dèzes Rolf Philipona

Hans-Rudolf Egli Frank Preusser

Charles Fierz Eric Reusser

Karl Föllmi Bruno Schädler

Alain Geiger Urs Schaltegger

Bernard Grobéty Manfred Thüring

Martin Hoelzle Helmut Weissert

Hans Hurni Urs Wiesmann

Adrian Jakob Adrian Wiget

Eduard Kissling Eric Zechner

Rainer Kündig François Zwahlen

Local Organizing Committee

François Zwahlen (President) Philippe Renard

Sabine Erb Mario Schirmer

Nico Goldscheider

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Participating Societies and Organisations

Commission for Research Partnerships with Developping Countries (KFPE)

Commission of Oceanography and Limnology (COL)

International Geographical Union, Commission Geography and Public Policy (IGU)

International Union of Geological Sciences, Swiss Committee (IUGS)

Kommission der Schweizerischen Paläontologischen Abhandlungen (KSPA)

NCCR North-South

Open Source Geospatial Foundation (OSGeo)

Schweizerische Geotechnische Kommission (SGTK)

Swiss Academic Society for Environmental Research and Ecology (SAGUF)

Swiss Agency for Development and Cooperation

Swiss Association of Geologists (CHGEOL)

Swiss Federal Institute of Aquatic Science and Technology (EAWAG)

Swiss Geodetic Commission (SGC)

Swiss Geography Association (SGV)

Swiss Geological Society (SGG/SGS)

Swiss Geological Survey (swisstopo)

Swiss Geomorphological Society (SGGm/SSGm)

Swiss Geophysical Commission (SGPK)

Swiss Hydrological Commission (CHy)

Swiss Society for Hydrogeology SGH

Swiss Society for Hydrology and Limnology (SGHL / SSHL)

Swiss Meteorological Society (SGM)

Swiss National Science Foundation

Swiss Paleontological Society (SPG/SPS)

Swisspeace Foundation

Swiss Society for Quaternary Research (CH-QUAT)

Swiss Snow, Ice and Permafrost Society (SIP)

Swiss Society of Mineralogy Petrography (SMPG / SSMP)

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Water Across Boundaries

Espace Louis-Agassiz 1, Aula des Jeunes-Rives, Neuchâtel

14:00 - 14:15 François Zwahlen President SGM 2009

Opening address

14:15 - 14:45 Gordon Young President IAHS

Scientific understanding: essential for sound water resources management (Joint IUGG-CH & IUGS-CH Union Lecture)

14:45 - 15:15 Janet Hering EAWAG

Geochemical Perspectives on Water Quality

15:15 Coffee break

15:45 - 16:15 Steven Ingebritsen United States Geological Survey, USGS

The Role of Groundwater in Geologic Processes

16:15 - 16:45 Robert Cramer Conseil d’Etat de Genève

L’eau : élément fédérateur de la politique transfrontalière

16: 45 - 16:50 Musical Interlude

16:50 - 17:40 Helmut Weissert Bernard Grobéty Pierre Gander Christian Meyer Martin Hoelzle Gilles Borel Daniele Biaggi Christoph Heinrich

Communications Platform GeosciencesPresentation SGM 2010 in FribourgCommunication Erlebnis Geologie 2010Swiss Commission of Palaeontology PrizeSwiss Snow, Ice and Permafrost Society PrizeSwiss Geological Society AwardCHGEOL AwardPaul Niggli Medal

17:40 - 17:45 Musical Interlude

17:45 - 18:00 Nexans Award

18:00 - 18:05 Musical Interlude

18:05 - 19:30 Aperitif & Posters

20:00 Swiss Geoscience Party = “Cocktail Dînatoire” on a boat in the port of Neuchâtel (reservation required)

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ion0. Plenary Session

1 Hering J.: Geochemical Perspectives On Water Quality

2 Ingebritsen S.: The Role of Groundwater in Geologic Processes

3 Young G.: Scientific understanding: essential for sound water resources management

1

Geochemical Perspectives On Water Quality

Janet G. Hering

eawag, Überlandstrasse 133, Dübendorf, Switzerlandjanet.hering@eawag.ch

As a sustainable source of safe drinking water, groundwater has many advantages over surface water, most no-table its natural protection from the pathogens that are a leading cause of child mortality in developing coun-tries. As tragically illustrated in South and Southeast Asia, however, consumption of groundwater can also pose health risks due to exposure to geogenic contaminants. This presentation will examine the biogeochemical controls on groundwater quality, particularly the concentration of the geogenic contaminants arsenic and flu-oride. The occurrence and mobility of geogenic contaminants will be discussed in terms of the composition of geological source materials and the biogeochemical processes by which geogenic contaminants are mobilized and sequestered.

2

The Role of Groundwater in Geologic Processes

S.E. Ingebritsen

U.S. Geological Survey, Menlo Park, California, USA

Historically, interest in groundwater and other subsurface fluids was confined to a few specific disciplines in the earth sciences, notably groundwater hydrology, soil physics, engineering geology, petroleum geology, and petroleum engineering. These disciplines tended to be “applied” in nature, with practitioners concentrating on the immediate and practical problems of water supply, water quality, mine dewatering, deformation under structural loads, and the location and recovery of fluid hydrocarbons. This situation has changed over the past few decades. Hydrogeologists and geologists are now actively exploring the role of groundwater and other sub-surface fluids in such fundamental geologic processes as crustal heat transfer, ore deposition, hydrocarbon migration, earthquakes, tectonic deformation, diagenesis, and metamorphism. This talk will emphasize (1) the links between groundwater processes and deformation, seismicity, and permeability and (2) recent advances in understanding of fluid flow and heat transfer at the mid-ocean ridge.

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Scientific understanding: essential for sound water resources management

Gordon Young

President, International Association of Hydrological Sciences

The presentation looks at water from the perspectives of the freshwater hydrologist and the manager of water resources and examines the theme of the meeting – “Water across boundaries” – from a number of different view points.

Hydrological sciences are placed within the broader context of earth sciences and various “boundaries” are considered:

• between hydrology and atmospheric and ocean sciences;• between hydrology and the biological sciences;• between hydrology and volcanic activity.

Within hydrology various “boundaries” are considered:

• between the various phases of water – solid, liquid and gaseous;• between surface waters, soil moisture and groundwaters.

The interactions between hydrology and human activities are then considered both from the impact of humans on the hydrological cycle through changes in land surface characteristics, through the impact of dams and di-versions and through the introduction of pollutants from a variety of sources into the hydrological system.

Water managers must be concerned with a number of human needs for water which must always be balanced by consideration of impacts on the natural environment. They must bridge the divides between hydrological knowledge and understanding and the need to manage wisely for the betterment of the human condition and must learn to use hydrological knowledge to better inform their management decisions. They must also think across the “boundaries” between the various uses and challenges of water:

• Water for the basic human needs of food security and health;• Water for social development;• Water for economic development – the need for water for energy and for industry;• Water security from floods and droughts and pollution spills;• Water for the essential maintenance of natural ecosystems.

Thus they need to consider the management of water challenges in an integrated fashion – this is the rationale for Integrated Water Resources Management; a mental challenge to cross sectoral boundaries.

The challenges for the water managers do not end here; water almost always flows across administrative boundaries whether these be at the very local level between neighbouring houses or settlements, or at provin-cial or state level (The Cantonal level in the case of Switzerland) or at international level. And the flow of water is not only on the surface of the land but also within aquifers at depth. Not only does water physically flow across administrative boundaries but there are divides between the bureaucracies at these various administra-tive levels – and those “boundaries” must also be crossed.

Lastly the water manager must bridge the divides between actions within the “water box”, ie the need to think holistically when considering the suite of water uses and challenges, and the positioning of water issues within the much broader framework of social and economic development. These last divides are perhaps the most dif-ficult navigate.

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es 1. Water across (scientific) boundaries

Eduard Hoehn, Adrian Jakob, Ronald Kozel, Urs Mäder, Bruno Schädler, Mario Schirmer

Swiss Hydrological Commission CHy, Swiss Society for Hydrogeology SGH, Swiss Society for Hydrology and Limnology SGHL, Rock-Water Interaction Group, Uni Bern, Eawag Swiss Federal Institute of Aquatic Science and Technology

1.1 AlaouiA.,WeingartnerR.:Caractérisationhydrodynamiquedesprincipauxtypesdesol

1.2 Alt-EppingP.,WaberH.N.,DiamondL.W.:Insightsfromcoupledthermal-hydraulic-chemicalmodellingofgeochemi-calprocessesincarbonateandsilicate-dominatedreservoirswithindeepgeothermalsystems

1.3 BabicD.,JenniR.,ZwahlenF.:Transferofsolutesunderforestedwatersheds

1.4 BadouxV.,PerrochetP.:Well-headcapturezonesdelineationintransientflowconditions:theuseofequivalentstea-dy-stateapproximations

1.5 BonalumiM.,AnselmettiF.,KägiR.,MüllerB.,WüestA.:Particlesinreservoirwatersaffectedbypumpstorageopera-tions

1.6 ChèvreN.,GuignardC.,BaderH.P.,ScheideggerR.,RossiL.:Sustainablemanagementofurbanwater:substanceflowanalysisasatool

1.7 deHallerA.,TarantolaA.,MazurekM.,SpangenbergJ.:Calcite-celestiteveinsandrelatedpastfluidflowthroughtheMesozoicsedimentarycoveratOftringen,nearOlten

1.8 DiemS.,VogtT.,HoehnE.:SpatialcharacterizationofhydraulicconductivityoftheThurtal-aquiferatthetestsiteWiden

1.9 DominikJ.,VignatiD.A.L.:Metalpartitioninginaquaticsystems:frominterdisciplinaryresearchtoenvironmentalpractice.

1.10 DriesnerT.CoumouD.,WeisPh.:Howwaterpropertiescontrolthebehaviourofcontinentalandseafloorhydrother-malsystems

1.11 DucommunR.,ZwahlenF.:Tracertestsinurbanisedsites:atoolforabettercharacterisationofgroundwatervulne-rabilityinurbanareas

1.12 EwenT.,RindererM.,BosshardTh.,SeibertJ.:Aspectralanalysisofrainfall-runoffvariabilityforselectSwisscatch-ments

1.13 GermannP.:Gravity-drivenPoiseuille-flowinthelithosphere

1.14 GlenzD.,RenardPh.,PerrochetP.,AlcoleaA.,VogelA.:AsynthesisofavailabledatatoanalyzetheinteractionbetweentheRhôneRiveranditsalluvialaquifer

1.15 Gremaud V., Goldscheider N.: Impacts climatiques sur la recharge d’un système karstique englacé, Tsanfleuron-Sanetsch,Alpessuisses

1.16 GuédronS.,VignatiD.A.L.,DominikJ.:Partitioningoftotalmercuryandmethylmercurybetweencolloidsandtruesolutioninoverlyingandinterstitialwaters(LakeGeneva).

1.17 HindshawR.,ReynoldsB.,WiederholdJ.,KretzschmarR.,BourdonB.:TrendsinstreamwaterchemistryattheDammaglacier,Switzerland

1.18 HuggenbergerP.:Processesatandacross the interface: Lessons lerned fromrivergroundwater interactionsunderdifferenthydrologicconditions

1.19 HunkelerD.,AbeY.,AravenaR.,ParkerB.,CherryJ.:Thefateoforganiccontaminantsatthegroundwater-surfacewaterinterface

1.20 HuxolSt.,HoehnE.,SurbeckH.,KipferR.:Thoronasapossiblemarkertracingsurfacewater/groundwaterinterac-tion

1.21 ImfeldG.,NijenhuisI.,NikolauszM.,RichnowH.H.:Variabilityofinsitubiodegradationofchlorinatedethenesinaconstructedwetland(NexansAwardLaureate2009)

1.22 JaegerE.B.,LorenzR.,SeneviratneS.I.:Roleofland-atmosphereinteractionsforclimateextremesandtrends

1.23 JordanF.,PhiliponnaC.,HellerPh.:Swissrivers.ch–Onlineriverforecastprediction

1.24 KöplinN.,ViviroliD.,WeingartnerR.:TheinfluenceofclimatechangeonthewaterbalanceofmesoscalecatchmentsinSwitzerland

1.25 LaigreL.,Arnaud-FassettaG.,ReynardE.:PalaeoenvironmentalmappingoftheSwissRhoneriver

1.26 LüthiM.:Storageandreleaseofwaterandchemicalspeciesinglaciers

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1.27 Marzocchi R., Pera S.: Groundwater and tunneling: implementation of a geochemicalmonitoringnetwork in thesouthernSwitzerland

1.28 MBockP.,LoizeauJ.-L.:Dynamicsofcolloidconcentrationsinasmallriverrelatedtohydrologicalconditionsandlanduse

1.29 MolnarP.,PeronaP.,BurlandoP.:Waterdisturbanceastheorganizerofriparianvegetation

1.30 NitscheM.,BadouxA.,TuriwskiJ.M.,RickenmannD.:CalculatingbedloadtransportratesinSwissmountainstreamsusingnewroughnessapproaches

1.31 NiwaN.,RossiL.,ChèvreN.:Pollutiondeseaux:lasantéest-elleunlevierpourmettreenplaceunegestionintégréeàl’echelledubasinversant?

1.32 PreisigG.,PerrochetP.:Effectivestressandfracturepermeabilityinregionalgroundwaterflow:numericalcompari-sonofanalyticalformulas

1.33 RickenmannD.:Debrisflows,landslides,andsedimenttransportinmountaincatchments

1.34 SchillE.,AbdelfettahY.,AltweggP.,BaillieuxP.:Characterisationofgeothermalreservoirsusing3Dgeologicalmodel-lingandgravity

1.35 SchneggP.-A.:FieldFluorometerforSimultaneousDetectionof3ColourlessTracers

1.36 SchwankM.,VölkschI.,MätzlerCh.,StähliM.:RecentResearchontheRemoteRetrievalofSoilMoisturefromSpacewithMicrowaveRadiometry

1.37 SinreichM.,v.LützenkirchenV.,MatousekF.,KozelR.:GroundwaterResourcesinSwitzerland

1.38 SteinmannM.,PourretO.:Theroleofthecolloidalpoolfortransportandfractionationoftherareearthelementsinstreamwater

1.39 TonollaM.:MicrobialcommunitiesinthesteepgradientsofthemeromicticlakeCadagno

1.40 VennemannT.,FontanaD.,PaychereS.,AmbadiangP.,PiffarerioR.,FavreL.:Dissolvedinorganiccarbonanditsstableisotopecompositionasatracerofgeo-,bio-,andanthropogenicsourcesofcarbon

1.41 VogtT.,SchneiderP.,SchirmerM.,CirpkaO.A.:High-resolutiontemperaturemeasurementsattheriver–groundwaterinterface:Quantificationofseepageratesusingfiber-opticDistributedTemperatureSensing

1.42 vonFumettiS.,GusichV.,NagelP.:Naturalsprings-thelivingpassagebetweengroundwaterandsurfacewater

1.43 WaberN.H.:Porewaterasanarchiveofthepalaeo-hydrogeologyduringtheHoloceneandPleistocene

1.44 Wanner Ch., Schenker F., Eggenberger U.: In-situ Remediation of Polluted Groundwater: A TransdisciplinaryApproach

1.45 WeisPh.,DriesnerTh.,CoumouD.,HeinrichCh.A.:Onthephysicalhydrologyofhydrothermalsystemsatmid-oceanridges

1.46 WüestA.,JarcL.,PascheN.,SchmidM:Onelake,twocountriesandalotofmethane-theconceptforaviableextrac-tionofanunusualresource

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Caractérisation hydrodynamique des principaux types de sol

A.Alaoui&R.Weingartner

Groupe d’hydrologie, université de Berne, Hallerstrasse 12, 3012 Berne, Suisse(alaoui@giub.unibe.ch)

Lacaractérisationhydrodynamiquedesprincipauxtypesdesolsuissesn’estpasencoreappréhendée.Elledépendnonseu-lementdutypedusoletdesespropriétésphysiquesmaissurtoutdesastructurefonctionnelle.L’aspecthydrodynamiquedusoln’estabordéqueparunanglethéoriqueounumérique.Danscetteperspective,nousavonsoeuvrépourmettreaupointuneméthoderobusteetfiablepourestimerquantitativementlefluxàtraverslazonenonsaturéeetdéfinirlerisqueliéautyped’écoulement(Alaouietal.,2003).Lebutdecetteétudeestlacaractérisationhydrodynamiquedesprincipauxtypesdesolàpotentielagricolepourl’estimationdufluxd’eautransitantversleseauxsouterrainespermettantdeprocéderàuneévaluationdeleurdegrédevulnérabili-té.Laméthodeutiliséedanscetteétudeest jugéerobustepourdeuxprincipalesraisons: i) lesmesuresdelateneuràpartirdesquelleslemodèleMACRO(Jarvis,1994)aétécalibrésonttrèsprécises(intervalledetempsdemesurevarieentre1et5minutes)ettrèsdenses(effectuéeslelongduprofiledusoltousles10cm)etii)lemodèleutiliséestbasésurlesprincipesphysiquesdusol.Decefait,lescalculsdesimulationsontfiablesetpeuventêtreextrapolésàd’autressolssimilaires(demêmetypeetmêmetexture).Lessolsétudiésprésententunrisquedepollutioncertainencasd’applicationdepesticidesouherbicidesquandilssonthumidesoutrèshumidescommec’estlecasdessolsbrunsetsolsbrunsacides.Lessolsbrunslessivéspeuventprésentercerisqueenétatsecethumide.Quantauxsolsàgley,ilsprésententunrisquedepollutionrelatifs’ilssontsecs.Lerisqueaugmenteavecl’humidité.Quandcessolssontsurdesnappesphréatiquesfluctuantes,leseauxsouterrainespeuventêtrecontaminéesparruissellementverslesrivièressilesolestenpenteouparpercolationverticaleversl’eaudelanappequiremonterapidementensurfacedanslecasd’uneplaine.Cesrésultatsmontrentengénéralquelessolsneprésententpasderisquemajeurquandilssonttrèssecs.Lecaséchéant,lespesticidesetherbicidespourraientêtreappliquéesdurantcespériodespourautantquecessolsnesubissentpasd’aversesdurantlesjoursquisuiventcetteapplication.Ilesturgentd’établirunecartepédologiqueauniveausuissequitiendracomptedutypedesol,desatextureetdurisquedepollutionqu’ilprésenteencasd’utilisationd’herbicidesoudepesticides.Cettecarteserviraauxpratiquantsdans lesdomainesdusoletdel’hydrologie.Laprésenteétudeestenfaiteàlabasedecettecartographieetdevras’étendreauxsolsagricolesdeculturedifférente.L’impactdelaculturesurlastructuredusoldevraitêtrealorsévalué

REFERENCESAlaoui,A,Germann,P, Jarvis,N,Acutis,M., 2003.Dual-porosity andKinematicWaveApproaches toassess thedegreeof

preferentialflowinanunsaturatedsoil.HydrolSciencesJ.48(3):455–472Jarvis,N.,1994.TheMACROmodelVersion3.1–Technicaldescriptionandsamplesimulations.ReportsandDissertations

no.19,DepartmentofSoilScience,SwedishUniversityofAgriculturalSciences,Uppsala,Sweden,51pp

1.2

Insights from coupled thermal-hydraulic-chemical modelling of geoche-mical processes in carbonate and silicate-dominated reservoirs within deep geothermal systems

Alt-EppingPeter,WaberH.Niklaus&Diamond,LarrynW.

Institute of Geological Sciences, Rock–Water Interaction Group, University of Bern, Baltzerstrasse 1-3, CH-3012 Bern (alt-epping@geo.unibe.ch)

Weusecoupledthermal-hydraulic-chemicalmodelspatternedafter thegeothermalsystemsatBadBlumau,Austria,andBasel,Switzerlandtotrackthefateoffluidsthatoriginatefromacarbonateandasilicate-dominatedgeothermalreservoir,

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srespectively, on theirpassage through thegeothermal system.Weusenumerical simulations to explore1) geochemicalconditionsintheundisturbedreservoir,2)chemicalandhydrological implicationsofreinjectingtheusedfluidintothereservoir,3)mineralscalingandtherateatwhichitoccursand4)boreholecorrosionandgeochemicalfingerprintsindica-tingincipientcorrosion.

Thecompositionofthefluidinthereservoirisbufferedbythemineralogyoftheaquiferrockatlocaltemperatureandpressure conditions. Changes in pressure and conductive temperature during ascent and descent of the fluid inducechangesinmineralsolubilities.Oversaturatedmineralsmaycausescalingwithintheborehole.Theprecipitationofmineralphasesintheboreholeisprimarilydictatedbythecompositionofthereservoirfluid.Thedistributionofmineralsisafunc-tionoftheflowandreactionrates.Mineralscalingwithintheboreholechangesthefluidcompositionandmaygraduallyclogtheborehole,therebyobstructingfluidflow.Becausedifferentmineralsexhibitdifferentsolubilitiesasafunctionoftemperature,themineralassemblagesthatprecipitateintheproductionwellaredistinctfromthoseintheinjectionwell.Forinstance,ifthefluidinthereservoirissaturatedinsilica,thentheprogradesolubilitybehaviourofsilicafavoursitsprecipitationintheproductionwell.Conversely,carbonatemineralstendtoprecipitateintheinjectionwellowingtotheirretrogradesolubilitybehaviour.However,calculatingthedistributionofmineralphasesiscomplicatedbythefactthattheprecipitationofsomemineralsiskineticallycontrolled,suchthattheymaycontinuetoprecipitatefarintotheinjectionwell(e.g.amorphoussilica)

Anymodificationofthefluidcompositioncausedbymineralprecipitationalongthefluid’spathwaymeansthattherein-jectedfluidisnolongerinequilibriumwiththereservoirrock.Consequently,rock-waterinteractionandfluidmixingatthebaseoftheinjectionwelldrivechemicalreactionsthatcausechangesinporosityandpermeabilityofthereservoirrock,potentiallycompromisingtheefficiencyofthegeothermalsystem.

Oneconcernduringgeothermal energyproduction is thatof chemical corrosionof theborehole casing. Fora rangeof"what-if" scenariosweexplore theeffectof corrosionon the fluidcompositionandonmineralprecipitation to identifychemicalfingerprintsthatcouldbeusedascorrosionindicators.Oncesuitableindicatorsareidentified,incipientcorrosioncouldbedetectedearlyonduringregularchemicalmonitoring.Corrosionofthecasingistypicallyassociatedwiththere-leaseofFeandH

2intothecirculatingfluid.However,theimplicationsofthisreleasedependonthelocalchemicalcondi-

tionswherecorrosionoccurs.Forinstance,elevatedH2inthefluidisacorrosionindicatoronlyifitisnotinvolvedinsub-

sequentredoxreactions.Similarly,lowH2concentrationsdonotruleoutpossiblecorrosion.

Ingeneral,theinterpretationofafluidoramineralsamplerequirestheunderstandingofchemicalprocessesthatoccuralongtheflowpaththroughoutthegeothermalsystem.Ifdirectobservationsarenotpossible,thenthisunderstandingcanonlybeachievedthroughnumericalsimulationsthatintegrateandcouplefluidflow,heattransportandchemicalreac-tionswithinone theoretical framework.Our simulationsdemonstrate that thesemodels areuseful forquantifying theimpactandminimizingtheriskthatchemicalreactionsmayhaveontheproductivityandsustainabilityofageothermalsystem.

1.3

Transfer of solutes under forested watersheds

BabićDomagoj*,JenniRobert**,ZwahlenFrançois*

*Centre of Hydrogeology and Geothermics (CHYN), Institute of Geology and Hydrogeology, University of Neuchâtel, Rue Emile-Argand 11, 2009 Neuchâtel, Switzerland**Bureau Nouvelle Forêt sàrl, Rte de la Fonderie 8c, 1700 Fribourg, Switzerland

TheALPEAUprojectaimstostrengthentheprotectingroleofforestswhenitcomestosustainablewaterresourcemanage-mentandquality.Thus,severalforestedwatershedswerechosen.TheGorgesdel'AreusewatershedislocatedovertheSwissJuramountainskarstiksystem,whereastheJoratforestandtheMontGiblouxaresituatedontheSwissPlateau,mainlycharacterizedbysandstoneformations.

Themaingoalofthisstudyistoassessthefateofcontaminants,suchasnitratesandpesticides,ontheirwaydownfromtheforestsoil,whichphysico-chemicalfeaturesarestronglylinkedtophytosociologicalcombinations,throughtheunsatu-ratedandsaturatedzonedowntothesystemoutlet.

Inkarsticareas, it is importanttodiscriminatebetweenwatercomingfromthesoilreservoir, theepikarst (interfacebe-tweensoilandkarst),thelowpermeabilityvolumes(therockvolumebetweentheepikarstandthesystemoutlet)andthe

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es freshlyinfiltratedrainwater.Todoso,gasesproducedinthesoilanddissolvedinrainwaterwillbeused.Acombinedradon,

CO2andTDGP(totaldissolvedgaspressure)measurementswillbecarriedoutinawateradductiontunnelattheGorgesde

l'Areusetestsite.Conductivity,temperature,turbidity,DOC(dissolvedorganiccarbon),nitrogenandcarbonisotopiccompo-sitionanddissolvedionswillalsobepartofthesurvey(Figure1).Additionalartificialtracingexperimentswillallowtogetinsightintothetraveltime,thestoragelocationandthedegradationkineticofdissolvedcompounds.

EventhoughtheMontGiblouxtestsiteissetontopofasandyaquifer,thesamemethodwillbeapplied,iftraveltimesareprovedtobeunderaweek.Indeed,radondecayswithahalfliveofabout4days,whereasCO

2reactswithcarbonateonits

waydowntothesaturatedzone.

ThemainfocusontheJoratforesttestsiteistheenvironmentalfateofcypermethrin,asyntheticinsecticideusedintimbertreatment,oilproductsusedinforestmanagementandtheirmetabolites.Firstofall,itisessentialtounderstandthehydrogeologicalbehaviourofthewatershed.Thus,aclassicalphysico-chemicalfollow-upwillbeestablishedatsomechosenwaterharnessing,completedwithcomparativetracertests.Then,woodenpileswill be set on treatment sites, treated with cypermethrin (within the range of legal concentrations) and spring waterwatchedover.Theexperimentwilloccurunderartificialsteadystateconditionsandduringheavyrainevents,asitisas-sumedtocausesignificantinfiltrationintotheaquifer.

Figure1.SchematicviewoftheGorgesdel'Areusetestsite(modfiedafterSavoyL.2007)

REFERENCESPerrin, J. 2003:Aconceptualmodelof flowand transport inakarstaquiferbasedon spatialand temporal variationsof

naturaltracers,Phdthesis,UniversityofNeuchâtel,Switzerland,227pages.Savoy,L.2007:Useofnaturalandartificialreactivetracerstoinvestigatethetransferofsolutesinkarstsystems,Phdthesis,

UniversityofNeuchâtel,Switzeland,194pages.Surbeck,H.2003:RadonandCO

2asnaturaltracersinKarstSystems,proceedingsofICGG7(2003),33-33.

Subeck, H. 2005: Dissolved gases as natural tracers in karst hydrogeology; radon and beyond, proceedings ofMultidisciplinaryApproachtoKarstwaterProtectionstrategy,UnescoCourse,Budapest,Hungary.

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Well-head capture zones delineation in transient flow conditions: the use of equivalent steady-state approximations

BadouxVincent*&PerrochetPierre**

*AF-Colenco Ltd. Täfernstrasse, 26, CH-5405 Baden (Vincent.badoux@af-consult.com)**Centre of Hydrogeology and Geothermics, Rue Emile-Argand 11, CH-2000 Neuchâtel (Pierre.perrochet@unine.ch)

Thedelineationofwell-headprotectionareasS1,S2andS3aswellascontributionzonesZuaimstopreventgroundwater

resourcesfrominstantaneousandperennialpollutions.Duetothestresstheyinduceonthelanduse,theseso-calledprotec-tionschemescausesocio-economicimpacts,thatbecomesnonnegligibleinhigh-densitypopulationarea,suchastheSwissPlateau.Thereforethedelineationofsuchprotectionschemesmustbedonewithcareinordertoguarantytheprotectionoftheresourceontheonehand,whileminimizingtheoverestimationoftheirsizeontheotherhand.

Aquifersarenaturalsystemsthatvarywithspaceandtime.Suchvariabilitywilldirectlyinfluencethewaycontaminantmigratesthroughtheaquiferandindirectlythedesignoftheprotectionschemes.Inpractice,characterizingtheresourcebyintegratingthisvariabilityrequiresmuchmoreeffortthanusingasimplehomogeneousmediumwithsteady-stateflowconditions.Consequentlythedelineationofprotectionschemesisoftendoneusinglowwatersteady-stateflowconditions,assumingthisconstitutesasaferapproach.However,byapplyingthissimplifiedmethodology, thesizeof theprotectionschemesisoverestimatedandtherelatedsocio-economicimpactsenhanced.

Anewmethodologyhasbeendevelopedtoidentifyflowconditionswheresteady-stateapproximationisjustifiedorwherethisapproximationshouldbeavoided(Badoux2007).Theratiobetweenthemeantransittimeandthefluctuationperiodappearstobeagoodcriteriontodistinguishbetweenthesetwocases.Whenthisratioissmallerthan0.5,thesizeoftheprotectionschemescanberigorouslyobtainedusinghighandlowwaterflowconditions.Whenthisratioisbigenough-theexactnumberissitespecific-theprotectionschemescanbeapproximatedbymeansteady-stateflowconditions.Inbetween,protectionschemescannotbeobtainedbyanysteady-stateflowconditions,exceptifsometransportparametersareadaptedinanappropriateway.

ThismethodologyhasbeenappliedtotheSeelandaquiferinCantonBern.

REFERENCESBadoux,V.2007.Analysedesprocessusadvectifs-dispersifsenmilieuxporeuxsouscontrainteshydrologiquespériodiques.

Implicationspourlaprotectiondescaptagesd’eauxsouterraines.PhDThesis,CHYN,Univ.Neuchâtel,293p.

1.5

Particles in reservoir waters affected by pump storage operations

BonalumiMatteo*,AnselmettiFlavio*,KägiRalf**,MüllerBeat***&WüestAlfred***

* Eawag, Swiss Federal Institute of Aquatic Science and Technology, Surface Waters – Research and Management, CH–8600 Dübendorf (matteo.bonalumi@eawag.ch)** Eawag, Urban Water Management, CH–8600 Dübendorf*** Eawag, Surface Waters – Research and Management, CH–6047 Kastanienbaum

Pumpedstoragehydroelectricityisusedtoevenoutthedailyandweeklyfluctuationsinenergyconsumptionbypumpingwatertoahigheraltitudereservoirduringlow-peakperiods,usingtheexcessbase-loadcapacityfromcoalandnuclearsour-ces.Thisprojectinvestigatestheeffectofthispumpstorageoperationsonparticlecharacteristicsinthewatercolumnandonresultingsedimentationprocesses.

Grimselsee(1908m)andOberaarsee(2303m),tworeservoirslocatedintheBerneseAlps,areconnectedsince1980byapumpstorageunitwhichexchangesanannualamountofwateramountingtoseveraltimesthevolumeofthereservoirs.Theim-pactofinitialdammingwasstudiedrecentlyfordownstreamareasandinthereservoirsthemselves.Thepartiallyglaciated

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es catchmentsfeedingthereservoirsleadtoanenormousinflowofinorganicparticlesduringsnowmeltinspring,resulting

inhighturbidityinthereservoirs.Comparedtopre-damconditions,reservoirsretainparticlesoflargergrainsizewhichwerepreviouslyreleasedtodownstreamareas (Anselmettietal.,2007). Inaddition,itwasdemonstratedthattheshiftofrunofffromsummertowinteraffectsthelightregimeand,consequently,theprimaryproductioninLakeBrienz(Fingeretal.2007;Jaunetal.2007).

Inordertounderstandtheeffectoftheincreasingpumpstorageoperationsonwaterturbidityandonparticlesize,watersamplingcampaignswereperformedseasonallyinbothreservoirsaswellasinthepowerstationconnectingthem.Turbidityseemstocorrelatestronglywithweatherconditionsandcatchmentcharacteristicsinsummerandwithpumpstorageacti-vityinwinter.Insummer,GrimselseewasfoundtobemoreturbidthanOberaarsee,whichhasastrongerthermalstratifi-cationandwhosecatchmentislessglaciated.Inwinter,GrimselseeandOberaarseeshowsimilarconditions.However,tur-biditywashigherclosetothein-/outlets,wherebothreservoirsarecontinuouslyexchangingwater.

Hydraulicmachinessuchasturbinescauseshearstressandturbulence,whichareknowntoinduceflocculationofparticles(Blaser&Boller,1998;Serraetal.,2008).InordertoinvestigatewhetherthiseffectoccursintheGrimselreservoirs,watersamplesweretakenupstreamanddownstreamoftheturbinesduringpumpstorageandpowerproductionregimes.Todate,SEMimageanalysesandparticle-counteranalysesdidnotdiscoveranyaggregationeffect,suggestingthatthethereisnotsignificantchangeinparticlecharacteristicsfromturbinepassages.

REFERENCESAnselmetti,F.S.,Bühler,R.,Finger,D.,Girardclos,A.,Lancini,A.,Rellstab,C.&Sturm,M.2007:EffectsofAlpinehydropower

damsonparticletransportandlacustrinesedimentation.AquaticSciences,69,179-198.Finger,D.,Bossard,P.,Schmid,M., Jaun,L.,Müller,B.,Steiner,D.,Schäffer,E.,Zeh,M.&Wüest,A.2007:Effectsofalpine

hydropoweroperationsonprimaryproductioninadownstreamlake.AquaticSciences,69,240-256.Jaun,L.,Finger,D.,Zeh,M.,Schurter,M.&Wüest,A.2007:Effectsofupstreamhydropoweroperationandoligotrophication

onthelight-regimeofaturbidperi-alpinelake.AquaticSciences,69,212-226.Boller,M.&Blaser,S.1998:Particlesunderstress.Wat.Sci.Tech.,37(10),9-29.Serra,T.,Colomer,J.&Logan,B.E.2008:Efficiencyofdifferentsheardevicesonflocculation.WaterResearch,42(4-5),1113-

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1.6

Sustainable management of urban water: substance flow analysis as a tool

ChèvreNathalie*,GuignardCécile*,BaderHans-Peter**,ScheideggerRuth**,&RossiLuca***.

* IMG - Faculté des Géosciences et de l’Environnement, Université de Lausanne, CH-1015 Lausanne (nathalie.chevre@unil.ch)**Eawag, CH-8600 Dübendorf*** IIE-ECOL, ENAC, EPFL, CH-1015 Lausanne

Pollutantsreleasedbycitiesintowaterareofmoreandmoreconcernastheyaresuspectedofinducinglong-termeffectsonbothaquaticorganismsandhumans(forexample,hormonallyactivesubstances).Thesubstancesfoundintheurbanwatercyclehavedifferentsourcesintheurbanareaandadifferentfateinthecycle.Forexample,thepollutantsemittedfromtrafficgettosurfacewaterduringraineventsoftenwithoutanytreatment,andarepartiallyremovedfromthewatercyclebysedimentation;pharmaceuticalsresultingfromhumanmedicaltreatmentsgettosurfacewatermainlythroughwaste-water treatment plants,where they are partly taken out fromwater. The residual concentrations can re-enter the cyclethroughdrinkingwater.Itisthereforecrucialtostudythebehaviorofxenobioticsintheurbanwatercycleandtogetflexi-bletoolsforurbanwatermanagement.

The substance flowanalysis (SFA), an extensionof the classicalmaterial flowanalysis originally developedbyBaccini&Brunner,hasrecentlybeenproposedasinstrumentforphosphorousmanagementinurbanwatersystem.SFAisbasedontheprincipleofmassbalance:asubstanceentersaclosedsystemandmaybetransportedortransformedinthesystemandmayalsoleavethesystem.Tobeusedasmanagementtool,SFAshouldbecoupledwithenvironmentalqualitycriteria.Thesevaluesexpressthemaxi-mumconcentration,whichistolerableforagivensubstanceinordertoprotectbothhumanandtheenvironment.Havingthislimitinmind,onecandetectthemostproblematicflowsandtakeactiontodiminishthem.Inourstudy,wetestedtheapplicationofSFAforalargenumberofclassesofxenobiotics,i.e.heavymetals,pharmaceuticals,biocidesandcosmetics,toevaluateitsuseforurbanwatermanagement.WechosethecityofLausanneascasestudyasmanydatawereavailable,onboththesewersystemandthewaterquality.

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sThecityof Lausanne,which isaround42km2with130’000 inhabitants. Lausanne isnear lakeGenevaand its effluentsmainlyreachthisecosystem,whichisarecreationalareaaswellasasourceofdrinkingwaterforthecity.ThesystemitselfisdescribedinFigure1andillustratedforcopper.Weconsideredthirteeninputsofthisheavymetalinthewatersystem:drinkingwater(I

1),roofs(I

2)andhousessides(I

3)runoff,roadrunoffcollectingcarbrakes(I

4),tiresabrasion(I

5),motoroil

residues(I6)anddrydeposition(I

12),particlesfromcatenariesfromtrolleybuses(I

7),inputsthroughtrains,i.e.particlesfrom

catenaries(I8),brakes(I

9)andwheels(I

10)abrasion,inputthroughboats(I

11)andrainwater(I

13).Transfercoefficientswerees-

timatedbasedonmeasurementorhypotheses.Forcopper,thewaterqualitycriterionwasgivenbytheSwisslegislationandthesedimentqualitycriterionproposedelsewhere.

TheSFAofcoppershowedthatthecityofLausannereleasesabout600Kgand900Kgperyearofthisheavymetalinrespec-tivelythewaterandthesedimentsoflakeGeneva.TheseestimationswerevalidatedbymeasurementsofcopperintheLakenearLausanne.Inthesediments,thecontinuousenrichmentinduceshighconcentrationsofthisheavymetal,whichareabovetherecommendedqualitycriterion.ByusingtheSFA,wecouldidentifythatcoppermainlyreachestheLakewithstormwater,i.ewithoutbeingremovedbyanytreatment.Themajorsourcesarethecatenariesofthetrolleybusesandtheroofsrunoff.Areductionofthecontaminationofthewatersystemwouldthereforeincludeactionsatthislevel(forexamplethetreatmentoftheroofsrunoff).SFAwasalsoappliedtobiocidesandpharmaceuticalswithinterestingresults(notshownhere).

Figure1:DescriptionoftheurbaindrainagesystemofLausanneandapplicationtocopper.The“I”flowsstayfor“Input”.The“k”flows

forthetransfercoefficients.

REFERENCESBacciniP.,&BrunnerP.,1991:Metabolismoftheanthroposphere,Springer,Berlin,Germany.ChèvreN.,GuignardC.,RossiL.,PfeiferH.-R.,BaderH.-P.,andScheideggerR.Substance flowanalysisasa tool forurban

watermanagement:thecaseofcopperinLausanne,Switzerland,Submitted.MacDonaldD., Ingersoll C., and Berger T., 2000:Development and evaluation of consensus-based sediment quality

quidelinesforfreshwaterecosystems,ArchivesofEnvironmentalContaminationandToxicology,39,20-31.

1.7

Calcite-celestite veins and related past fluid flow through the Mesozoic sedimentary cover at Oftringen, near Olten

deHallerAntoine*,TarantolaAlexandre*,MazurekMartin*&SpangenbergJorge**

*RWI, Institute of Geological Sciences, University of Bern, Baltzerstr. 1-3, CH-3012 Bern (DeHaller@geo.unibe.ch)**Institute of Mineralogy and Geochemistry, University of Lausanne, Building Anthropole, CH-1015 Lausanne

Thestudyisbasedoncoresamplesfromtherecentlydrilled,719mdeepboreholeatOftringen(nearOlten),locatedinthenorthwesternMolassebasin,at1.5kmfromthefrontalthrustoftheFoldedJura(Waber,2008).Veinsofcalcite(±celestite,pyrite)occurinthewholeMalmsequence(upto8veins/m),includingthemoreclay-richEffingenMember.Todate,suchanintensityofveiningintheEffingenMemberhasnotbeenfoundinotherdeepboreholeslocatedintheMolassebasin.Mostoftheveinsarerelatedtotectonicactivity,butclay-filledkarststructuresarerecognizedintheupperGeissbergMember

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es limestone,andafewstructuresprobablyrelatedtothediageneticprocessesaredocumentedintheEffingenMember.Fluid

inclusionsshowaveragesalinitiesbetween3.3and4.4wt%eq.NaClincelestiteand2.7wt%eq.NaClincalcite.Averageho-mogenizationtemperaturesincalcitefluctuatebetween56and68°C,withabroadincreasewithdepthandnocorrelationwithsalinity.

Malmwhole-rockcarbonateshaveδ18Ovaluesfluctuatingwithinanarrowrange,probablydeterminedbyequilibriumwithseawater(Fig.1A).Their87Sr/86Srratiosfollowawell-defineddepthprofilewithminimumvaluesinthemiddlepartoftheEffingenMember,fittingwithOxfordianseawater(McArthuretal.,2001;Fig.1B).Nocorrelationisobservedbetween87Sr/86Srandclaycontent,andvalueshigherthancontemporaryseawatermightberelatedtotheincorporationofradiogenicdetritalcarbonate.

Theδ18Ovaluesofveincalcitearesystematicallylowerthanthecorrespondingwholerockcarbonate (Fig.1A),consistentwithprecipitationfromseawaterat50-70°C.Theδ34Sandδ18OvaluesofveincelestitefollowabacterialreductiontrendpointingtoMioceneseawatersulfate.Twoveinpyritesgavenegativeδ34Svaluesconsistentwithbacterialsulfatereduction.Calciteandcelestiteofdiageneticoriginhave87Sr/86Srratiosthatareindistinguishablefromthecorrespondingwholerockcarbonatefraction.Incontrast,the87Sr/86Srratiosofepigeneticveincalciteandcelestiteshowasystematicenrichmentinradiogenic Sr compared to the correspondingwhole-rock carbonate and require an external Sr source.OnlyBurdigalianseawater,atthetimeofUpperMarineMolasse(OMM)deposition,hadan87Sr/86Srratiohighenoughtoexplainthehighestvalueobtained(Fig.1B).

TherocksoftheMalm-Doggersequencewerenotpervasivelyaffectedbyfluidspost-datingburialdiagenesis,andtheinflu-enceofsuchfluidswasrestrictedtoopenstructures.TheMolassebasinsubsidedintheBurdigalian(KuhlemannandKempf,2002;Mazureketal.,2006),andtheveinsmightrecordtectonicactivityrelatedtothisprocess.Calciteandcelestiteprecipi-tatedfromdescendingseawaterduetoheatingto50-70°C,whileprecipitationofpyriteresultedfrombacterialreductionofpartoftheseawatersulfate.

Figure1.Oxygenandstrontiumisotopicdata.

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sREFERENCESKuhlemann J.,&Kempf,O. 2002: Post-Eocene evolutionof theNorthAlpine ForelandBasin and its response toAlpine

tectonics.Sed.Geol.152,45-78.McArthur,J.M.,Howarth,R.J.,&Bailey,T.R.2001:Strontiumisotopestratigraphy:LOWESSVersion3:Bestfittothemarine

Sr-isotopecurve0-509Maandaccompanyinglook-uptableforderivingnumericalage.J.Geol.109,155-170.Mazurek,M.,Hurford,A.J.&Leu,W.2006:Unravellingthemulti-stageburialhistoryoftheSwissMolasseBasin:Integration

ofapatitefissiontrack,vitrinitereflectanceandbiomarkerisomerisationanalysis.BasinRes.18,27-50.Waber, N., ed. 2008: Borehole Oftringen:Mineralogy, Porosimetry, Geochemistry, PoreWater Chemistry. NAGRA

ArbeitsberichtNAB-08-18,Nagra,Wettingen,Switzerland.

1.8

Spatial characterization of hydraulic conductivity of the Thurtal-aquifer at the test site Widen

DiemSamuel,VogtTobias,HoehnEduard

Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf (samuel.diem@eawag.ch)

Formanyhydrogeologicalandmodelingproblemsonascaleoftheorderof10-100m,anassessmentofthespatialdistribu-tionofhydraulicconductivity(h.c.)isofgreatimportance.ThisisoneofthetasksoftheReCorDproject(RestoredCorridorDynamics)ofCCES(CompetenceCenterEnvironmentandSustainabilityoftheETHDomain).Thisprojectaimsatunderstan-ding,howriverrestorationmeasuresaffectriver-rivercorridor-groundwatersystemsinhydrologicandecologicterms.TheriverThurandthealluvialgravel-and-sandaquiferoftheperialpineThurvalleyfloodplainwerechosenforfieldinvestiga-tions.Inthisaquifer,thedistributionofh.c.attherequiredscalehasnotyetbeeninvestigated.Thus,theaimofthisMasterThesisistocharacterizethehydrogeologyoftheaquiferatatestsiteinthecentralpartofthevalley(Widen,Felben-Well-hausen/TG),whichextendstoabout10x20m(aquiferthickness,7m),byusingdifferentmethodsondifferentscales.Workincludedloggingofcoredrillings,sievingofthegravelsamples(decimeterscale)andtheconductionandanalysisofapum-pingtest(decameterscale),flowmeterlogsandslugtests(meterscale),withappropriatemethods.Exceptfortheslugtests(14wells),fourfullypenetratingwellswithpiezometersofadiameterof4.5”wereused.Theanalysisofthesetestsresultedinvaluesofh.c.

Thesieve analyses(verticalintervalsofsamples:0.5m)wereperformedwiththecorematerialofthefourwells.Thevaluesofh.c.calculatedafterCasati(1959)ledtosmallabsolutevaluesandanarrowdistribution(n=53,µ=-2.73m/s,σ2=0.01;whereµ=log

10geometricmean,σ2=log

10variance).ThesmallvariabilitycanbeexplainedbytheapproachoftheformulaofCasati

(1959), takingintoaccountfivegrainsizefractionsandassumingabsenceofthesecondaryporosityofthematerial.Thesmallabsolutevaluesoriginatefromthecalibrationoftheformulatoaspecificaquifer.Sieveanalysesarewellsuitedforaroughestimateofh.c.ofperialpinealluvialgravel-aquifers,withanaccuracyofafactorofabout2.Thepumping test(pumpingwellisoneofthefourwells,headobservationsinnineadditionalwells)involvesalargeaquifervolume.Asforallpumpingtests,theresultingvalueofh.c.(herecalculatedafterNeuman(1972,inKruseman&DeRidder1991)) isbiasedbyhighlyconductivezonesandcorrespondstotheupperlimitofthespectrumofthenaturalvariability(µ=-1.83m/s).Thisvalueisadequateforlargescaleinvestigations.Flowmetermeasurementswerecarriedoutatintervalsof0.25minthefour4.5”-piezometers.Asforallflowmetertests,ananalysiswiththemethodofJavandel&Witherspoon(1969,inMolz1989)resultedinverticalprofilesofrelativevaluesofh.c.Therelativevaluescanbecalibratedtoabsolutevalues:Heretheyarecalibratedrelativetothemeanh.c.ofthepumpingtest,whichintegratesalargeaquifervolume(totalofn=29,µ=-1.83m/s,σ2=0.14;calculatedforanaverageof0.5mintervals).Thebiasoftheresultofthepumpingtestisthustransferredtotheresultsoftheflowmetermeasurements.Therelativeprofileofh.c.shouldratherbecalibratedwiththeresultofteststhatinvolveonlyasmallaquifervolume,e.g.slugtestsinfullypenetratingwells,whicharehardtorealizeinahighlyconductiveaquifer.Soflowmeterlogsaretheadequatemethod,iftherelativeverticaldistributionofh.c.isofprimaryimportance.Slug tests.Fordetailedinformationaboutthespatialdistributionofh.c. intheorderof10-100m,whichisneededintheReCorDprojectforthemodelingofgroundwaterflow,soluteandheattransportatsmallscales,pneumaticmulti-levelslugtests(withasystemofdoublepackers)wereappliedin117intervalsof0.5mlengthof14piezometers(analyzedafterBouwerandRice1979,SpringerandGelhar1991,inButler1998).Theseexperimentsresultedinthefollowingdistributionofh.c.:n=117,µ=-2.38m/s,σ2=0.11.

Astatisticalevaluationofthevaluesofh.c.fromtheabovemethodsshowedthattheresultscannotbecompared.Thus,thechoiceofthemethodtoassessthedistributionofh.c.hastobedoneaccordingtotheproblemandtherequiredlevelof

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es detail.Theslugtestsresultedinthebestabsoluteandrelativerepresentationofthedistributionofh.c.,comparedtothe

otherthreemethods:Theabsolutevaluesofh.c.donothavetobecalibratedwiththeresultofadifferentmethod,thevaluesofh.c.areaccurateandcovermostofthenaturalrangeofh.c.AstatisticalcomparisonofsieveanalysesoftheWidentestsitewiththoseofthewholeThurvalleyhasshownthatthedistributionofd

10,d

50andd

60grainsizefractionsaresimilarin

thewesternpartofThurvalley.Probably,thedistributionofh.c.assessedfortheWidentestsitecanalsobeusedforthewesternpartofthevalley,asthissiteseemstobelongtothesamefacies.Todecreasetheworkloadrequiredforslugtestsandtoincreasethelevelofdetailinh.c.assessments,Irecommendacombinationofhydraulictestingwithhighresolutiongeophysicsandtheuseoftracers.ThedevelopmentofgeophysicalandtracermethodsareanintegralpartoftheReCorDproject.

REFERENCESButler,J.J.JR.1998:Thedesign,performance,andanalysisofslugtests.LewisPublishers.Casati,A.1959:DieDurchlässigkeitkiesigerBöden.MonatsbulletinSVGW6,120-126.Kruseman,G.P.&DeRidder,N.A.1991:Analysisandevaluationofpumpingtestdata.ILRIPublication47,SecondEdition.Molz,F.J.1989:Theimpellermeterformeasuringaquiferpermeabilityvariations:Evaluationandcomparisonwithother

tests.WaterResour.Res.25(7),1677-1683.

1.9

Metal partitioning in aquatic systems: from interdisciplinary research to environmental practice.

DominikJanusz*&VignatiDavideA.L.**

* Institut F.-A. Forel, Section de sciences de la Terre et d’environnement, Université de Genève, CP 416, 1290 Versoix – janusz.dominik@unige.ch ,** CNR-IRSA, Via del Mulino 19, 20047 Brugherio (MB), Italy – vignati@irsa.cnr.it

Knowledgeofpartitioningofmetalsisfundamentalforunderstandingtheirtransportandtheiravailabilitytoaquaticor-ganisms.Furthermore,aconsiderablefractionofmetalsinrivers,lakesandcoastaloceanmaybeofanthropogenicoriginwithconcentrationsapproachingthelevelsconsideredharmfulforaquaticecosystems.Measuringand,whenpossible,pre-dictingmetal partitioning therefore becomes essential for environmental risk assessment and associatedmanagementplans.

CurrentEuropeanandSwisslegislationsfixenvironmentalqualitystandards(EQSs)onmetalsforthefilterablephase;defi-nedasthemetalfractionpassingthroughtheporesofa0.45µmfilter.Alargefractionof“filterable”metalsisactuallyasso-ciatedwithsmall-sizecolloidsandthusisnottrulyinsolution.Unlikemetalsintruesolution,colloidalmetalscanberemo-ved fromthewatercolumnviacoagulationand/oraggregationandsedimentationprocesses.Moreover,metalsboundtocolloidsarenotavailabletosomeorganisms(e.g.,algae),butmightbeavailableforothers(e.g.,zooplankton).Thesediscre-panciesbetweenfundamentalknowledgeandcurrentenvironmentalpracticesraisetwomajorquestions:a)Isitpossible,anduseful,todeterminemetalpartitioninginmonitoringprograms?b)Howcantheknowledgeofmetalpartitioningbet-weencolloidalandtrulydissolvedphasesbeusedinenvironmentalassessment?

Thepublisheddataindicatethatmetalsoflowsolubilityinoxicconditions(e.g.,Cr(III),Fe,Mn,Ti,Pb)arepredominantlyassociatedwithcolloids,whilemetalspreferentiallyforminganioniccomplexesoccurmostlyintruesolution(e.g.,Cr(VI),Mo,U,V).Partitioningofelementsoccurringasdivalentcations(e.g.,Cu,Zn,Cd,Ni,Hg)dependslargelyonphysico-chemi-calconditionsofambientwaterandonthequantityandqualityofcolloids.

ForthepriorityelementsmentionedinEuropeanlegislation,theliteraturedataindicatethat,ingeneral,NiandCdhaveloweraffinityforcolloidsthanPbandHg(fig.1).Notehoweverthatapartoftheobservedvariabilityiscausedbypersistingtechnicallimitations;i.e.tangentialflowfiltration(themostwidelyusedtechniquetoseparatecolloidalandtrulydissolvedfraction inpartitioningstudies)notbeingstandardizedandprone toartifacts. In suchsituation,measurementofmetalpartitioningbetweencolloidsandtruesolutioninroutinemonitoringprogramsremainsunlikelyandprobablynotadvisa-ble.Nevertheless, inferring the percentage of truly dissolved fraction from the total filterable fractionhas proven to befeasibleforsomeelements(Vignatietal.2005).Suchinformationcanbeusedtorefinemodelsonelements’environmentalfateandalsoprovideamorerealisticevaluationoftoxicityatprimaryproducerlevel;whichishighlyrelevanttotheassess-mentofecologicalrisk.Indeed,algalbioassayscarriedoutinthepresenceoforganiccolloids,demonstrateddecreasingto-xicitywithincreasingfractionofmetalsboundtocolloids(Koukaletal.2003,2007).

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Fig.1.Percentageoftoxicmetalsassociatedwiththecolloidalfractionaccordingtopublisheddatafromfreshwaterandestuarineorcoa-

stalsystems(compiledinVignatietal.2009).Barsrepresenttherangebetweenthemeansofthelowerandtheupperlimitsineachstudy.

REFERENCESKoukal,B.,Guéguen,C.,Pardos,M.&Dominik,J.2003:Influenceofhumicsubstancesonthetoxiceffectsofcadmiumand

zinctothegreenalgaPsedokirchneriellasubcapitata.Chemosphere,53,953–961.Koukal,B.,Rossé,P.,Reinhardt,A.,Ferrari,B.,Wilkinson,K.J.,Loizeau,J.-L.&Dominik,J.2007:EffectofPseudokirchneriella

subcapitata(Chlorophyceae)exudatesonmetaltoxicityandcolloidaggregation.WaterRes.,41,63-70.VignatiD.A.L.,CamussoM.&Dominik J.2005:Estimationof the trulydissolvedconcentrationsofCd,Cu,Ni,andZn in

contrastingaquaticenvironmentswithasimpleempiricalmodel.EcologicalModelling184,125–139.Vignati D.A.L., Valsecchi, S., Polesello, S., Patrolecco, L, & Dominik, J. 2009: Environmental realism andWFD

implementation: chemical and ecological relevance of particle-colloid-true solutionpartitioning of pollutants forsurfacewatermonitoring.TrendsinAnalyticalChemistry,28,159-169.

1.10

How water properties control the behaviour of continental and seafloor hydrothermal systems

DriesnerThomas*,CoumouDingeman**&WeisPhilipp*

*Institute of Isotope Geochemistry and Mineral Resources, ETH Zentrum, CH-8092 Zürich (thomas.driesner@erdw.ethz.ch)**Potsdam Institute for Climate Impact Research, Telegrafenberg A62, D-14412 Potsdam

Theflowpatternsandthermalevolutioninhydrothermalsystemsareofprimeinteresttoavarietyofbasicandappliedgeosciencedisciplinesrangingfrombiogeoscienceresearchonlifeinextremeenvironmentsthrougheconomicgeologytogeothermalenergyexploration.Duetotheextremetemperature-pressureconditionsaswellasthedifficultaccesstomanyofthesesystems(e.g.thoseatmid-oceanridges),insighthasmostlybeengainedfromnumericalsimulation.

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es Inthecaseofcontinentalhydrothermalsystemsheatedbymagmaticintrusions,numericalsimulationhasshownthatthe

system-scalepermeabilitystructureisaprimeordercontrolonhowmuchtheconvectinghydrothermalfluidmaybeheated.Thisisaresultofthedifferentrateswithwhichconvection(withthefluidflowrateprimarilybeingcontrolledbypermea-bility)transportsheatawayfromthesourceandconduction(intheessentiallyimpermeablehotmagmaticsource)deliversheattothefluid(Hayba&Ingebritsen,1997;Driesner&Geiger,2007).Ontheotherhand,fluidpropertiessuchasthepositionofthewaterboilingcurveintemperature-pressurespaceareamajorcontrolonthestyleofhydrothermalfluidflowintheupflowzone.

Formid-oceanridgehydrothermalsystems,recentdevelopmentsinnumericalsimulationtechniqueshaverevealedthatthetemperature-pressure-compositiondependenceoffluidpropertiessuchasviscosity,density,andheatcapacityisafirstordercontrolonhydrothermalsystembehaviour.Forexample,byheatingwaterfromambienttemperaturetoto200°C,viscositydropsbyoneorderofmagnitude.Thisincreasesthemobilityofwaterbythesameamountasaoneorderofmagnitudein-creaseinpermeability.Hence,hotwatercanessentially“byitself”createcorridorsofhighhydraulicconductivityinenviron-mentsofotherwisehomogenouspermeability.Asaresult,strongself-organizationeffectsmayoccur,theprimeexamplebeingtherecentpredictionofpipe-likehydrothermalplumesunderlying“blacksmoker”hydrothermalsystemsandbeingsurroundedbynarrowcylindricalzonesofintense,warmrecharge(Coumouetal.,2008).Currentresearchfocusesonthequestiontowhatdegreetheseeffectsinterferewiththoseresultingfromthepermeabilitystructureofthecrust(seeWeisetal.,thisvolume).

Figure1.Thermalstructureofthehydrothermalplumeunderlyingamid-oceanridgeblacksmokerfield.Ahotcentralupflowzonewith

temperaturesupto380°Cissurroundedbyanarrowrechargezonewithtemperaturesbetween100and200°C.FromCoumouetal.(2008)

Foroceanicsystemswithahomogenouspermeabilitydistribution,itcanbeshownthatthereisastronginterplayoffluidpropertiesandpermeabilitythatdeterminesthesystem’stemperatureaswellasitsabilitytoconvecttheincomingheat.Numericalsimulations,verifiedbysemi-analyticalcalculations,showthattypicalblacksmokertemperaturescanonlybeachievedwhenpermeabilityisLESSthanabout3x10-14m2.Athigherpermeabilities,thetemperaturesarelowersincefluidflowratesaretoofasttoallowstrongerheatingnearthemagmaticheatsource.Belowthispermeability,fluidpropertieslimitthemaximumtemperatureofthesystemtoca.400°C.Similarly,fortypicalheatflowratesatthebottomofthesystem,notallincomingheatcanbeconvectedaway,andmagmaeruptionstotheseafloormaypotentiallybetheonlywaytoba-lancethetotalheatinput.

Towhatdegreetheinfluenceoffluidpropertiesmayplayaroleintheformationoforedepositsorintheoperationofgeo-thermalsystemsissubjecttoongoingresearch.

REFERENCESCoumou,D.,Driesner,T.&Heinrich,C.A. (2008)The structureanddynamicsofmid-ocean ridgehydrothermal systems.

Science321,1825-1828Driesner,T.andGeiger,S. (2007)Numerical simulationofmultiphase fluid flow inhydrothermal systems. InFluid-Fluid

Interactions(A.LiebscherandC.A.Heinrich,eds.)ReviewsinMineralogyandGeochmistry65,pp.187-212Hayba,D.O., and Ingebritsen, S. E. (1997)Multiphase groundwater flownear coolingplutons. Journal ofGeophysical

Research102,12,235–12,252.

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Tracer tests in urbanised sites: a tool for a better characterisation of groundwater vulnerability in urban areas

RomainDucommun*,FrançoisZwahlen*

*Centre d’Hydrogéologie et de Géothermie (CHYN), Université de Neuchâtel, Emile-Argand 11, CH-2000 Neuchâtel, romain.ducommun@unine.ch

Vulnerability assessments and mapping methods (Vrba & Zaporozec 1994) are principally designed for natural areas.However,inurbanzones,thegroundwaterrechargeisstronglymodified,duemainlytosealingofsurfaceand/orpresenceofsubsurfacewatermainsandsewerpipes,whichcancontributetorecharge,orinverselyactasdrainsforwaterinsaturatedandunsaturatedzones(Lerner2002;Thomas&Tellam2006).Asrechargecanbeconsideredasakeyparameterforvulnera-bilityevaluation(e.g.,Aller,Bennettetal.1987),urbanprocesseswhichmodifygroundwaterrechargehavetobeincludedinanyvulnerabilityassessmentofgivenurbangroundwaterresources.Inthisperspective,multi-tracertestswerecarriedoutatlocalscaleintwourbantestsitesinSwitzerland:ColombierandNeuchâtel.TheColombiertestsiteislocatedinalowurbanisedarea,onquaternaryglacialsedimentsformingthePlateaudePlaneyse,whereasmallshallowaquiferispresentinthesiltyformations.TheNeuchâteltestsite,attheshoreofLakeNeuchâtel(Maladièrearea),islocatedinahighurbanisedarea,onhighlyheterogeneousanthropogenousbackfillmaterialand quaternary glacio-lacustrine sediments. The artificial conservative tracers (uranine, sulforhodamine B, duasyne andnaphtionate)wereinjectedinsealedandunsealedsurfaces,ordirectlyinsubsurfacerainwaterpipes.Inbothtestsites,tracerrecoverywasmonitoredinunderlyingurbanaquifers(wellsanddrainagecollectors),andinthedownstreampartofpipeswherethetracerinjectionswereperformed.TherecoveryresultsinColombierandNeuchâtel(exampleofbreakthroughcurveinfigure1)pointedoutdualroleofpipesonrecharge(increasingordecreasingrecharge),anincreaseinrechargeduetorunoffconcentrationattheboundariesofsealedsurfaces,andanincreaseinrechargeduetothepresenceofartificialbackfillmaterialsintheuppermostpartoftheunsaturatedzone.Notsurprisingly,increasedratesoftracerrecoveryduringwethydrologicalperiodswereobservedduringtheperformedtests.Effectsofthesevariousparametersonrechargewerefurtherinterpretedfromalocalurban-adaptedgroundwatervulnera-bilityperspective.Consequently,keyfactorslikethepresenceofundergroundpipes(inassociationwithpipeparameters:material,age,hydraulichead,etc),orthelocalmodificationsofhydraulicconductivityofsoil/subsoilformationsbyhumanactivity,havetobeintegratedinurbangroundwatervulnerabilityassessmentsandmappingmethods.

Figure1.BreakthroughcurveforsulforhodamineB(sulfoB)andtime-seriesforelectricalconductiity(EC),turbidity,dischar-ge,andwatertemperatureattheColombierdrainageoutlet(summer2007).Themajorrainfallevent(A)anditsnoticeablerelatedtracerresponseareindicated.

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Aller, Bennett, et al. 1987: DRASTIC: a standardized system for evaluating groundwater pollution potential usinghydrogeologicalsettings.U.S.EnvironmentalProtectionAgency(EPA),Ada,Oklahoma,USA.

Lerner2002:Identifyingandquantifyingurbanrecharge:areview.HydrogeologyJournal10(1):143.Thomas and Tellam 2006:Modelling of recharge and pollutant fluxes to urban groundwaters. Science of the Total

Environment360(1-3):158.Vrba and Zaporozec, Eds. 1994: Guidebook onMappingGroundwater Vulnerability. International Contributions to

Hydrogeology,vol.16.Hannover,HeinzHeiseGmbH.

1.12

A spectral analysis of rainfall-runoff variability for select Swiss catch-ments

TracyEwen*,**,MichaelRinderer*,ThomasBosshard**,andJanSeibert*

**Institute for Atmospheric and Climate Science, ETH Zurich, Universitätstr. 16, 8092 Zurich. *Department of Geography, University of Zurich, Winterthurerstr. 190, 8057 Zurich, (tracy.ewen@geo.uzh.ch)

Timeseriesanalysiscanprovideusefulinsightintothecomplexrelationshipsbetweenvariablesofinterest.Inparticular,analysisofprecipitationandrunoffforaparticularhydrologicalcatchmentallowsthephysicalcomplexityofthesystemtobebetterunderstood,bothspatiallyandtemporally.TheFouriertransformisoftenusedtoanalysethefrequencydomainoftimeseries,however,duetothenon-stationarityofclimatologicalandhydrologicalvariables,waveletshavebeenintro-duced to analyse the spectral properties over time by transforming a time series into two-dimensional time-frequencyspace.

Waveletshavebeenusedtounderstandthetemporalandspatialvariability incomplexhydrologicalsystemsthroughananalysisofrainfallandrunoff(fore.g.,Labatetal.,2000)andtocharacteriseremotewatershedsbasedonrunoffdataonly(Gaucherel,2002).Cross-waveletanalysisbetweenvariablesgivesfurtherinsightintothetemporalvariabilityoftherelation-ship (Grinstedetal.,2004)and insight intophysicalprocessesgoverning thesystem, inparticular, thebasinresponse torainfall,whichmayhelptoclassifycatchments.

Here,weusewaveletstoanalysedailyprecipitationandrunofftimeseriesfromtheRietholzbachandtheTösscatchmentsinSwitzerlandtobetterunderstandtemporalrelationships,withafocusonextremesduringthepast30years.Wefurtherinvestigatethespatialrelationshipbetweenprecipitationandrunoffandquantifytheprecipitationcontributionfromdif-ferentmeteorologicalstationstototalrunoffforeachcatchment.Wealsodiscusstheminimaltime-scalesneededtoade-quatelyrepresentthephysicalrelationshipsbetweenrainfallandrunoff(andhencetheclimatologicalsignal),whichcouldbeapplied,fore.g.,inordertoconstrainhydrologicalimpactstudies(Bosshardetal.,2009).

REFERENCESBosshard,T.Ewen,S.Kotlarski,andC.Schär,2009:Theannualcycleoftheclimatechangesignal-Animprovedmethodfor

useinimpactstudies,GeophysicalResearchAbstracts,Vol.11,EGU2009-7095.Gaucherel,C.,2002:Useofwavelettransformfortemporalcharacterizationofremotewatersheds,J.Hydrol.,269,101-121.Grinsted,A.,S.Jevrejeva,J.Moore,2004:Applicationofthecrosswavelettransformandwaveletcoherencetogeophysical

timeseries,NonlinearProc.Geophys.,11:561-566.Labat,D.,R.Ababou,A.Mangin,2000:Rainfall-runoffrelationsforkarsticsprings.PartI:convolutionandspectralanalysis,

J.Hydrol.,238,123-148.

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Gravity-driven Poiseuille-flow in the lithosphere

PeterGermann

Institute of Geography, University of Berngermann@giub.unibe.ch

Hydro-mechanicalconceptsofflowinpermeablemedia(likefissuredrocks,karstformations,unconsolidatedsediments,andsoils)arebasedonlaminarflowthatisdrivenbysomeforce(i.e.,anycombinationofthegradientsofgravity,density,pressure, osmosis, capillarity, andotherpotentials), and that encounters resistance (usually expressed as its inverse likepermeability or conductivity). Typical lengthand time intervals areup tokilometres andmonths in fissured rocks andgroundwatersystems,tenstohundredsofmetersandweekstodaysinkarstformationsandhillslopesoils,tensofmetersandhourstodaysinunsaturatedandunconsolidatedsediments,andsinglemetersandminutestohoursinunsaturatedsoils.Dependingontheproblemandthesystemathandthedimensionalitymayvaryfromonetothree,andflowdirectionsmayreverseasinfiltration/capillaryriseinsoilsmayillustrate.Inaddition,theflow-drivingforcemayalter,forinstance,fromgravity-dominatedinfiltrationtocapillarity-dominatedriseofsoilmoistureandtopressure-dominatedflowwhenthemediumbecomeswatersaturated.Inviewofthemanygroupsofprofessionalsdealingwithvariouskindsofflowandtrans-portinvariouskindsofpermeablemedia,avarietyofconceptsandmethodshaveevolvedthatadaptedtotheneedsoftherespectivegroups.Group-specificadaptationsincludemethodsandprotocols,timeandlengthscales,systemboundaries,anddegreeofintensityindealingwithspatialvariability.Forinstance,capillarityinthenon-saturatedrootzoneofsoilsissodominantthatsoilhydrologistsandsoilphysicistsrelatewatercontents,hydraulicgradientsandhydraulicconductivitiestoit.Ontheotherside,thevadosezone(i.e.,thenon-saturatedzone)ofunconsolidatedsedimentsbetweensoilsandground-watertablesisusuallysortofhydraulicandhydrologicalno-man'sland,whereasresearchonwaterflowinkarstsystemsandgroundwatersystemsfollowtheirownrules.

Aconceptofinfiltrationwillbepresentedthatassumesgravityasdominantdrivingforcewhichisbalancedbyviscosity.Asetofequationsevolvesthatdescribestheconstantvelocitiesofwettinganddrainingfronts,andthatdealswithtrailingwaves.Theapproachislinearbutdiscontinuous;itdoesnotrequirearepresentativeelementaryvolumewhichisconsiderasobstacletotheup-scalingofmostmodels.Theapproachallowsforsuperimposingflowsintimeandspace.Flowfore-ca-sting iseasy,however,hind-casting is impossibleafter flowshave joined.Fromneutronradiographycomesexperimentalevidencethattheapproachappliestosandlayersthatarethinnerthan1mm:Fromsandtankexperimentsweknowthatitappliestolayersasthickas2m.Thepropagationofwettingfrontsacross20mofunconsolidatedsedimentsandacross2kmoffissuredgraniteindicatetheapplicabilityoftheapproachtolargersystems.Moreover,itexplainsconceptuallytheformationoffingerflowinunsaturatedporousmedia.

1.14

A synthesis of available data to analyze the interaction between the Rhône River and its alluvial aquifer

GlenzDamian*,RenardPhilippe*,PerrochetPierre*,AlcoleaAndrés*,AlexandreVogel**

*Université de Neuchâtel, Centre d’ Hydrogéologie, Rue Emile Argand 11, CH-2000 Neuchâtel (damianglenz@unine.ch, philippe.renard@unine.ch, pierre.perrochet@unine.ch)** Etat du Valais - Service des routes et des cours d'eau, Projet Rhône, Av. de France 75, CH-1951 Sion (alexandre.vogel@admin.vs.ch)

Beforethefirst(1863-1894)andsecond(1930-1960)Rhonecorrections,thefloodsproducedbytheRhoneRiverhadregularlydisastrouseffectsfortheinhabitants.Recentevents(1987,1993and2000)revealedmajordeficienciesinfloodprotection,whichconfirmedthenecessityofthethirdregulationprojectoftheRhône.Inadditiontofloodprotection,theprojectaimsatenhancingtheecologicalaspectsoftheriver(OFEFP/OFEG2003).

Thegeneralapproachfollowedistowidentheriverbedbyafactorofatleast1.6.Thisimpliesinsomesectionsaloweringofthewater level intheriver.AsthegroundwatertableoftheRhonealluvialaquifer ispartlycontrolledbytheexchangesbetweentheaquiferandtheRhone,thewideningoftheriverbedmayinfluencethealluvialaquifer.Thecorrectionwillalsomodifythegeomorphologyoftheriverbed.Thismayaffectthepermeabilityoftheriverbedandthushaveaneffectontheexchangebetween the river and thegroundwater. For example, a loweringof thegroundwater tablemight induce land

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groundwatertablemightleadtoariseofgroundwaterinbuildingsorbyswampformation.

Toforecaststhosepotentialimpacts,itisnecessarytocharacterizethepresentsituationandtoanalysethecurrentstateoftheexchangesbetweentheriverandtheaquifer.Inasecondstage,anumericalgroundwaterflowmodelwillbeusedtosimulatethemainobservationandtoinvestigatethepossibleeffectsofamodificationoftheriverbed.Thecharacterizationoftheaquiferandthedesignoftheconceptualaquifermodelisbasedonabroadrangeofsourcesin-formationsuchasseismicsurveys,boreholes,piezometricheadmeasurements,wateranalysis,hydraulictests,etc.Sofar,theanalysisofthesedatahaveshownsomeimportantaspects.

First,thecontinuousmeasurementsofpiezometricdatashowthatthewatertableofthealluvialaquiferishighlyinflu-encedbythewaterleveloftheRhôneriver.Moreprecisely,thepiezometricmapsshowthatinalargeportionoftheregion,theleveloftheRhôneishigherthanthepiezometry.Thisindicateseitherrechargeconditionsordisconnection.Theassump-tionofrechargeisinagreementwithnewmaps(e.g.Fig.1)ofthehydrochemicaldatathatwereinterpolatedforthisstudy.Thosemapsshowthatlowconcentrationsofthedifferentchemicalspeciesaremostoftenmeasurednearthelowmineral-izedRhôneRiver.

Inaddition,thecomparisonofthehydrochemicaldatawiththelithologyofthevalleyslopesindicatesplaceswithaground-waterinflowfromkarsticaquifers.

Finally,theimportanceofthedrainageditchesonthegroundwaterflowisrevealedbythemapsofthewaterchemistry.Onthosemaps,theditchesformclearlyrecognizablebarriersbetweentwotypesofwater(e.g.higherandlowermineralizedwaters,onbothsidesoftheCanalduSyndicat,Fig.1).

Figure1.Interpolatedmap(kriging)ofelectricalconductivityintheRhoneaquiferbetweenSierreandBranson(Data:Highwaterlevels

1985).

REFERENCESOFEFP/OFEG,2003.Coursd’eausuisses.Pourunepolitiquedegestiondurabledenoseaux.Berne,12pages

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Impacts climatiques sur la recharge d'un système karstique englacé, Tsanfleuron-Sanetsch, Alpes suisses

GREMAUD Vivian*, GOLDSCHEIDER Nico*

*Centre d'hydrogéologie et de géothermie, Université de Neuchâtel, Rue Emile Argand 11, 2009 Neuchâtel, Suisse, vivian.gremaud@unine.ch, nico.goldscheider@unine.ch

Les glaciers de haute montagne accumulent une grande quantité d'eau en hiver, contribuant ainsi à la recharge des eaux souterraines durant les saisons chaudes. Actuellement les glaciers alpins sont globalement en retrait et certains vont dispa-raître dans les 50 prochaines années sous les effets des changements climatiques. La région de Tsanfleuron-Sanetsch dans les Alpes de Suisse occidentale est un site expérimental idéal pour étudier les interactions glacier-aquifère. En effet un gla-cier au recul très rapide et présentant un risque de disparition prochaine surmonte un aquifère karstique drainé principa-lement par la source de Glarey et utilisée pour l'approvisionnement en eau potable. De larges surfaces de l'aquifère sont exposées aux précipitions et à la fonte des neiges entre le glacier et ce captage. Ainsi, entre le glacier de Tsanfleuron et sa moraine de 1855 (petit âge glaciaire) la surface du karst a été polie par l'écoulement glaciaire, alors que des lapiaz typiques sont présents sous le cordon morainique. Géologiquement la zone est formée de roches sédimentaires jurassiques à paléo-gènes, plissée selon un large anticlinal limité au sud par un étroit synclinal au niveau du captage de Glarey. Les relations entre stratigraphie, tectonique, processus de recharge et drainage souterrain de l'aquifère karstique a été étudié par de mul-tiples méthodes, en particulier des essais de traçage et certains paramètres physiques mesurés en continu. La géométrie et structure du glacier de Tsanfleuron ont été étudiées par plusieurs campagnes géophysiques (méthode radio magnétotellu-rique RMT). Le volume de glace a été estimé à 102 millions de m3, correspondant à ~93 millions de m3 d'eau liquide disponi-ble pour recharger l'aquifère karstique et le soumettant à une variabilité journalière et saisonnière. L'eau de fonte produite par le glacier influence la géométrie des courbes de restitution et, par conséquent, les flux et le transport dans l'aquifère. Basé sur les prévisions climatiques, un modèle de disponibilité saisonnière de l'eau a été établi. L'hiver et le printemps présenteront un surplus d'eau alors que des périodes de manque d'eau seront à craindre lors de longues périodes sèches en été et automne, l'eau glaciaire étant absente. De plus les précipitations seront plus fortes mais plus rares et la demande en eau plus importante, particulièrement pour l'irrigation.

1.16

Partitioning of total mercury and methylmercury between colloids and true solution in overlying and interstitial waters (Lake Geneva).

Stéphane GUEDRON*, Davide A.L. VIGNATI**, Janusz DOMINIK*.

* Institut F.-A. Forel, Section de sciences de la Terre et d’environnement, Université de Genève, CP 416, 1290 Versoix (stephane.guedron@unige.ch)**CNR-IRSA, Via del Mulino 19, 20047 Brugherio (MB), Italy

Mercury is one of the priority metals on the list established by the EU legislation due to its bioaccumulation in the food chain (Morel et al., 1998). Mercury bioaccumulation and biomagnification (i.e., increasing concentrations across trophic le-vels) are mainly caused by the transformation of inorganic Hg into the organic form methylmercury (MeHg) (Fitzgerald and Lamborg, 2003). As it is the case for many other elements (Vignati et al., 2005), the partitioning of mercury and MeHg large-ly controls their bioavailability and transfer to the trophic chains. Furthermore, formation of MeHg is particularly active at the sediment water interface thus making the study of Hg and MeHg partitioning in interstitial waters a topic of utmost interest for Hg/MeHg biogeochemical cycles and the associated risk assessment. In this study, we used tangential flow filtration (TFF) to determine the partitioning of Hg and MeHg between operationally defined colloidal (0.45 µm – 3 kDa) and truly dissolved (< 3 kDa) fractions. Using ultraclean techniques (Cossa and Gobeil, 2000), blank values of 0.1–0.8 ng L-1 and < 0.01 ng L-1 were obtained for total Hg (HgT) and MeHg, respectively. We also adapted the TFF methodology to process volumes of 60 – 80 mL; corresponding to the amount of interstitial water (IW) re-covered from 4 cm of sediment after centrifugation and filtration.Sediment cores and overlying waters were collected at two sites with contrasting characteristics in Lake Geneva (Switzerland/France). Cores were sliced under nitrogen atmosphere to recover interstitial water. Interstitial water was filtered (0.45 µm) and then ultrafiltered. Total filterable Hg and MeHg concentrations were in the range 3.5–11 ng L-1 and 0.061–0.082 ng L-1, respectively. The percentage of Hg and MeHg associated with colloids were similar: 20–35% of total filterable concentrations.

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es To verify if truly dissolved concentrations of Hg/MeHg could be estimated from the more easily measured total filterable

concentrations, we combined our results with data available from literature. No significant correlation between filterable vs. truly dissolved concentrations were found for MMHg. On the other hand, significant Spearman correlations (R2 = 0.56; N = 30; p < 0.01 for freshwater data and R2 = 0.92; N = 23; p < 0.001 for oceanic water data) were obtained for total Hg. Our data superimposed rather well to the regression obtained for oceanic waters, rather than to the regression for freshwaters. We therefore surmise that the ligands controlling total Hg partitioning in IW are similar to those in oceanic coastal waters. The validity of this model should obviously be confirmed by future studies, but it opens an intriguing possibility to estimate Hg partitioning in IW and thus to refine the existing biogeochemical models.

REFERENCESCossa, D. and Gobeil, C., 2000. Mercury speciation in the Lower St. Lawrence estuary. Can. J. Fish. Aquat. Sci., 57: 138-147.Fitzgerald, W.F. and Lamborg, C.H., 2003. Geochemistry of mercury in the environment. In: B. Sherwood Lollar (Editor),

Treatise on Geochemistry. Elsevier, pp. 107-148.Morel, F.M.M., Kraepiel, A.M.L. and Amyot, M., 1998. The chemical cycle and bioaccumulation of mercury. Annual Reviews

Ecol.Syst., 29: 543-566.Vignati, D.A.L., Dworak, T., Ferrari, B., Koukal, B., Loizeau, J.L., Minouflet, M., Camusso, M.I., Polesello, S. and Dominik, J.,

2005. Assessment of the geochemical role of colloids and their impact on contaminant toxicity in freshwaters: An example from the Lambro-Po system (Italy). Environmental Science & Technology, 39(2): 489-497.

1.17

Trends in streamwater chemistry at the Damma glacier, Switzerland

Hindshaw Ruth*,**, Reynolds Ben*, Wiederhold Jan*,**, Kretzschmar Ruben** & Bourdon Bernard* *Institute of Isotope Geochemistry and Mineral Resources, Clausiusstrasse 25, CH-8092 Zürich (hindshaw@erdw.ethz.ch)**Insitute of Biogeochemisty and Pollutant Dynamics, Universitätsstrasse 16, CH-8092

The contribution of silicate weathering to global cationic denudation rates is not known precisely due to the difficulty of separating the weathering from silicate and carbonate minerals. Accurate quantification of in situ silicate mineral weathe-ring rates is required to constrain the carbon cycle. Small, mono-lithological catchments are ideal for elucidating the pro-cesses by which silicate rocks weather and how these processes change under varying seasonal conditions.

This work forms part of the multi-disciplinary BigLink Project which is investigating the 10.7 km2 granitic Damma catch-ment (Switzerland). The glacier has retreated rapidly, exposing fresh mineral surfaces allowing the initial stages of granite weathering to be studied. Stream waters were sampled for one year, with higher frequency sampling during the summer, in five different locations, in conjunction with high resolution hydrological and meteorological measurements. Selected isoto-pe ratios were analysed in addition to the overall chemical composition to characterise spatial and temporal variations in stream water chemistry.

After correction for atmospheric inputs, daily and seasonal cycles were clearly observed in the cation concentrations. The cyclic trends were independent of dilution and indicated the mixing of at least two distinct sources whose relative propor-tions changed over seasonal and daily timescales. In order to identify potential end-member sources, porewater and ground-water samples were also analysed. Our data show that these potential end-members are highly variable spatially and tempo-rally.

The different sources reflect differing water-rock interaction times as evinced by variable elemental ratios (e.g. Na/Ca) which were offset from bulk rock ratios. A groundwater contribution with Na/Ca ratios close to bulk rock values is dominant in winter. During increased surface discharge in summer, groundwater contributions are smaller and Na/Ca ratios are offset from those of bulk rock.

This study shows that even in a lithologically well-constrained watershed, large variations in cation flux occur over daily and seasonal timescales, primarily due to changing hydrological conditions. Thus, knowledge of the hydrology of a catchment is essential to quantify cyclic cationic denudation rates, and to estimate silicate weathering rates.

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Processes at and across the interface: Lessons lerned from river ground-water interactions under different hydrologic conditions

PeterHuggenberger

Angewandte und Umweltgeologie, Dept. Umweltwissenschaften, Uni Basel. Peter.huggenberger@unibas.ch

Canalizationofmanyriversinthe19thcenturystronglyinfluencedtheeconomicdevelopmentandurbanizationofmostEuropeancountries.Togetherwithtechnicaldevelopmentsinagriculture,aseriesofenvironmentalproblemssuchasfloo-ding,groundwaterpollutionandecologicalchanges,includingthedecreaseofcharacteristichabitatsofriverinelandscapes,werecreated.Mostoftherivervalleysareimportantgroundwaterreservoirs,inparticularincentralEurope.Thesereservoirsareoftenhighlyendangeredduetointenseagriculturalandindustrialactivitiesandadensenetworkofurbanareascon-nectedbynumeroustrafficlines.Additionally,thehighpermeabilityoffluvialsediments(esp.fluvialshapedaquifertypesofalpinetype),thefrequentlyobservedlackofathickprotectivecoverlayerandtheexchangeprocesseswithsurfacewatersresultinahighvulnerabilityofgroundwaterresources.Formulatedgoalsforasustainabledevelopmentofwaterresourcesguidemitigationstrategiesandconsiderdefinedstan-dards,i.e.naturalcompositionofsurfacewaters.Majoreffortsforfuturetransdisciplinaryresearch,withrespecttohydro-logicalregimes(lowandhighflow)orgroundwaterflowregimes,willconcentrateontheknowledgeofthestructuraldyna-micsoftheriverandrelatedgroundwatersystems.Toidentifyhydrologicalandhydrogeologicalsystemprofiles,methodo-logiestoquantifyandcontroltheseprofilesmustbedevelopedandapplied.Thiscanbeachievedbytheimplementationofmanagementsystemsthatincludeobservationsystemsandthedevelopmentofnumericalmodelscombinedwithspecificfieldexperimentsandscenariodevelopment.Theintegralofchangesinriverstructuresinthecatchment(i.e.lackofretentionspace)hasalreadydemonstratedseriousconsequencesduringmajorfloods.Duetotheexperiencegainedfromthehazardousfloodeventsinthelasttwentyyears,thepollutionproblemsandthelossofcharacteristicriverinelandscapes,mostcountrieshaveadoptedamorecomprehen-siveviewofrivers.Itisrecognizedthattheconsiderationofprocessesofriver-groundwaterinteractionsareimportant,whichsignificantlydifferfornaturalandchannelizedstates.Withinthiscontext,positiveandnegativeaspectsofriver-groundwater interactionforchannelizedandnon-channelizedsurfacewatersareinvestigated.Theinteractionofsurfaceandsubsurfacewatersissubjecttocontinuousdynamicsinvolvingwaterbudgets,waterqualityandflowpatterns.Whenconsideringquantitativehydrologicalaspectsofriver-groundwaterinteraction,thetransientcharacterofriverbedpermeabilityisanessentialfactor.Sedimenterosionaswellastransportanddepositionprocessesareinfluencedbyriversthatareabletoexerttheirnaturaldynamics.Asaconsequence,thevarianceoftheriverbedpermeabilityisincreasedtemporarily,influencinginfiltrationratesandgroundwatermixingratios,aswellasresidencetimesforgroundwaterfromdifferentprovenance.Tounderstandthedynamicsofriver-groundwaterinteraction,ourinvestigationsfocuson: (1)theevaluationoftransienthydraulic boundary conditions, including the transient character of riverbed permeability and (2) qualitative aspects ofsurfacewatersandgroundwater.Resultsfromexperimentsofselectedriver-reachesarepresented,including:(1)adequateobservationsystemsthatfacilitatethemeasurementofgroundwaterparametersatdifferentdepths,aswellasthedefinitionofsamplingstrategies,(2)non-destructivegeophysicalmethods(Georadar,Geoelectrics)withintheriverbedandtheriparianzone,aswellas(3)subsequenthighresolutiongroundwaterflowandtransportmodeling,includingscenariotechniques,modelcalibrationandsensitivityanalyses.Interactionprocessesarestudiedataregionalandalocalscale(e.g.UpperRhineGraben,individualcatchmentareas,river-reachesandcapturezonesofextractionwells).

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The fate of organic contaminants at the groundwater-surface water interface

HunkelerDaniel*,AbeYumiko*,AravenaRamon**,ParkerBeth***&CherryJohn***

*Centre for Hydrogeology, University of Neuchâtel, Rue Emile Argand 11, CH-2009 Neuchâtel (Daniel.Hunkeler@unine.ch)**Department of Earth and Environmental Sciences, University of Waterloo, 200 University Avenue West, Waterloo ON N2L 3G1, Canada***School of Engineering, University of Guelph, Guelph ON N1G 2W1, Canada

Persistentgroundwatercontaminantswithlittletendencytosorbtothematrixoftentraveloverextendeddistancesinaqui-fersandcaneventuallyreachsurfacewaterbodiesorothergroundwaterdependentecosystems.Inthevicinityofsurfacewaterbodies,sedimentqualityandredoxconditionsfrequentlychangeandbiologicalactivityisenhancedcreatingaddi-tionalpossibilitiesforcontaminantretentionanddegradation.Towhatextentthesealteredconditionsaffectthecontami-nantfatestronglydependsongroundwaterflowpaths,whichareoftenhighlycomplexinvicinityofsurfacewaterbodies,andtheresidencetimeofgroundwaterinzoneswithgeochemicalconditionssuitableforcontaminantdegradationorreten-tion.

Inthepresentation,resultsfromtwofieldsitesarediscussedwhereatetrachloroethene(PCE)andatrichloroethene(TCE)plume,respectivelydischargestoastream.PCEandTCEarewellsuitedcompoundstoevaluatetheeffectofchanginggeo-chemicalconditionsonthecontaminantfatesincetheirdegradationishighlydependentontheredoxconditions.PCEandTCEdegradebyreductivedechlorinationundermoderatelyreducingconditions,whiletheirdegradationproductscis-1,2-dichloroethene (cDCE)andvinylchloride (VC) requirestronglyreducingconditions for furtherreductive transformation.Alternatively,cDCEandVCcanalsobeoxidizedtoCO2underaerobicandmoderatelyreducingconditions.Atthetwosites,contaminanttransformationwascharacterizedusinghighresolutionsamplingandanalysisofredoxsensitivespecies,dis-solvedcontaminants,stableisotoperatiosofcontaminantsandmicrobialparameters.

AtthePCEsite(Abeetal.,2009),thecontaminantplumetravelledthroughasandyaquiferunderconfinedconditionsanddischargedintothestreamthroughanapproximately2mthicklayerofsilty-clayeystreambedsedimentrichinorganicmat-ter(Figure1a).Whilenodegradationoccurredinthesandyaquifer,highlyvariabledegradationwasobservedinthestre-ambedsedimentsrelatedtosmallscaleheterogeneities.Thedegreeofdegradationreachedfromnodegradationinsandierzoneswhererapidgroundwaterdischargeoccurredtocompletereductivedechlorinationinclay-richzoneswherehighlyreducingconditionsprevailed.TheTCEsiteconsistedofanunconfinedsandyaquifer(Chapmanetal.,2007).Intheupgradi-entpartofthesite,groundwatertravelledatadepthofseveralmetersbelowgroundsurfacewhile inthedowngradientzone,thewatertablewasclosetothesurfaceandcontaminantspartlymigratedthroughorganiccarbonrichfloodplainsedimentswherereductivedechlorinationoccurred(Figure1b).However,theshallowwatertableconditionsfavoredground-waterdischargeintopondsandcreeks.Hence,whiletheaquifershowedasubstantialcapacityforcontaminantdegradation,mostofthecontaminantstraveledviathesesmallcreekstothemainstream.Thestudiesdemonstratethatinordertogaininsightintothecontaminantfateatgroundwater-surfacewaterinterfacesagoodunderstandingofthegeochemicalvariabilityandgroundwaterflowpathsisessential.Atbothsites,zoneswithfavor-ableconditionsforcontaminantdegradationoccurred.However,thesezoneswerepartlyby-passedandoverallonlypartialeliminationofthecontaminantsoccurred.Finally,thestudyalsoillustratestheneedforhighresolutionsamplingtode-velopaconsistentconceptualmodelofcontaminantmigrationanddegradationatgroundwater-surfacewaterinterfaces.

a) PCEsite

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Figure1:Schematiccrosssectionofthefieldsiteswherecontaminantplumesdischargeintoastreamunderconfined(a)andunconfined

(b)conditions.

REFERENCESAbe,Y.,Aravena,R.,Parker,B.L.andHunkeler,D.,2009.Evaluatingthefateofchloriantedethenesinstreambedsediments

bycombiningstableisotope,geochemicalandmicrobialmethods.J.Contam.Hydrol.,107(1-2):10-21.Chapman,S.W.,Parker,B.L.,Cherry,J.A.,Aravena,R.andHunkeler,D.,2007.Groundwater-surfacewaterinteractionandits

roleonTCEgroundwaterplumeattenuation.J.Contam.Hydrol.,91:203-232.

1.20

Thoron as a possible marker tracing surface water / groundwater interaction

Huxol,Stephan1,Hoehn,Eduard1,Surbeck,Heinz2,Kipfer,Rolf1,3

21Eawag, Swiss Federal Institute of Water Science and Technology, CH-8600 Dübendorf, Switzerland (Stephan.huxol@eawag.ch)2 Nucfilm Ltd., CH-1792 Cordast, Switzerland3 Institute of Isotope Geology and Mineral Resources, Swiss Federal Institute of Technology (ETH) Zürich, Switzerland

Radon(222Rn,half-life3.6d)andthoron(220Rn,half-live55.6s)arethemostlonglivedisotopesofthenoblegasradon.Aspartofthetwonaturalradioactivedecayseriesof238Uand232Th,respectively,theyarereleasedfrommineralstofluids(e.g.soilgas,groundwater)byα-decayfromtheirprecursors 226Raand224Ra,respectively(emanationprocess).Bothradon-isotopescanbefoundinsoilgas.222Rnhasbeensubjecttoresearchforalongtimeandiswellknowntooccurinaquaticsystems,especiallyingroundwater.Itisoftenusedasatracerforassessingresidencetimesofsurfacewatersinfiltratingtogroundwater.Incontrast,studiesonthoroninaquaticsystemsarerare.However,thoronisexpectedtobefoundingroundwater,too,whereitcouldbeusedforanassessmentofmixing.Also,forassessingupwelling/downwellingprocessesintheriverbed,thoronisapotentiallypromisingtracer.

Uptonow,wedidnotfindanythoroningroundwater.Thisismostprobablyrelatedtothefastdecayofthoron,whichresultinarestrictedmobility,andthetime-consumingdetectionsystemtodeterminethoron.Furthermore,thegeophysicalandgeochemicalcharacteroftheradionuclidesofthe238Useriesisdifferentfromthatofthe232Thseriesand,therefore,theap-pearanceofradoninaquaticsystemsdoesnotnecessarilyreflecttheoccurrenceofthoron.

Inordertoconceptuallydescribethethoronemanationweformulatedthefollowingworkinghypothesis:Theprecursorsofradonandthoron(224,226,228Ra)areknowntobeslightlymoresolubleinanoxicthaningroundwater(inoxicwater,Raisonlyhardlysolubleandremainessentiallyinthesolidphase).Ifsuchanoxicgroundwatergetsintocontactwithoxygen,radiumtendstoco-precipitatewithMnandFeoxide/hydroxides.Asaresult,theemanationofthorontothewaterphasemaybeenhancedbyradium,whichisattachedtosurfacecoatingsoftheprecipitates.Inordertoenhancethesamplingprocedure,wemodulatedaconventionalsamplingsystem(RAD7,coupledwithcommercialdegassingunitRADAQUA)byinterconnect-inganadditionalclosedairloopwithadjustablediaphragmpumptodecreasetheresidencetimesofwaterandairbetweensamplingandmeasurement.

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es Primaryresultsconfirmthefeasibilityofthoronanalysisinoxygen-poorsprings,especiallyifironandmanganeseprecipi-

tatesarepresent.Gamma-spectroscopyofprecipitatesat thesprings’soutlet showedtherelativehighcontentof thoronprecursors and daughter products in the Fe andMn oxides/hydroxides.Moreover, α-spectrometric analysis showed thatthoronprecursorsanddaughtersareconcentratedonthesurfaceof theprecipitates,whichfurtheraddevidencetoourconceptualviewofthoronemanation.

1.21

Variability of in situ biodegradation of chlorinated ethenes in a constructed wetland

ImfeldGwenaël*,NijenhuisIvonne*,NikolauszMarcell**&RichnowHansH*

*Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, D-04318 Leipzig (gwenael.imfeld@engees.u-strasbg.fr)*Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstr. 15, D-04318 Leipzig

Thespatialandtemporalbiogeochemicaldevelopmentofamodelwetlandsuppliedwithcis-andtrans-1,2-dichloroethenecontaminatedgroundwaterwascharacterizedover430daysbyhydrogeochemicalandcompound-specificisotopeanalyses(CSIA).Thehydrogeochemistrydramaticallychangedovertimefromoxictostronglyreducingconditionsasemphasizedbyincreasingconcentrationsofferrousiron,sulfide,andmethanesinceday225.δ13Cvaluesfortransandcis-DCEsubstantial-lychangedovertheflowpathandcorrelatedovertimewithDCEremoval.Thecarbonenrichmentfactorvalues(ε)retrievedfromthewetlandbecameprogressivelylargerovertheinvestigationperiod,rangingfrom-1.7±0.3‰to-32.6±2.2‰.ThisindicatedthatlessfractionatingDCEoxidationwasprogressivelyreplacedbyreductivedechlorination,associatedwithamorepronouncedisotopiceffectandfurtherconfirmedbythedetectionofvinylchlorideandethenesinceday250.ThisstudydemonstratesthelinkagebetweenhydrogeochemicalvariabilityandintrinsicdegradationprocessesandhighlightsthepotentialofCSIAtotracethetemporalandspatialchangesofthedominantdegradationmechanismofDCEinnaturalorengineeredsystems.

Inparallel,thedynamicsandcompositionofmicrobialcommunitiesintheaqueousphaseofthemodelwetlandwascha-racterized.PCR-DGGEanalysisofwater sampleobtained fromdifferentpartof thewetlandrevealed thatchangesof thebacterialcommunitystructurescoincidedwithasuccessionofthehydrogeochemicalconditionsinthewetland,fromoxictowardsanoxicconditions.Duringthistransitionphase,theappearanceofvinylchlorideandethenecorrelatedwiththepresence of putative dechlorinating bacteria (Dehalococcoides spp.,Geobacter spp. andDehalobacter spp.). Additionally,shiftofDCEisotopiccompositionindicatedtheprogressiveprevalenceofreductivedechlorinationinthewetland.AlthoughtheDCEdegradationprocessesvariedovertime,biodegradationactivitywasmaintainedinthewetlandsystem.16SrRNAgenelibrariesrevealedthatProteobacteriaaccountedfor>50%of16SrRNAgenesclonelibraries,whereas~17%ofthese-quencesfromthewetlandwererelatedtosulphatereducers.Basedonanmultiple-methodapproach,thisstudyillustratesthelinkagebetweenmicrobialcommunitydynamicsandcomposition,changesofhydrochemicalconditionsandprocessesofDCEdegradationinawetlandsystem.

1.22

Role of land-atmosphere interactions for climate extremes and trends

EricB.Jaeger*,RuthLorenz*&SoniaI.Seneviratne*

*Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland (eric.jaeger@env.ethz.ch)

ProcessesactingattheinterfacebetweenthelandsurfaceandtheatmospherehaveastrongimpactontheEuropeansum-merclimate,particularlyduringextremeyears.Theseprocessesare toa largeextentassociatedwithsoilmoisture.Thispresentationprovidesanoverviewonrecentanalysesinvestigatingtheroleofsoilmoisture-atmospherecouplingfortheEuropeansummerclimateovertheperiod1959-2006usingsimulationswitharegionalclimatemodel.

The setof experiments consistsof a control simulationwith interactive soilmoisture, and sensitivity experimentswithprescribedsoilmoisture.Soilmoisture-climateinteractionsarefoundtohavesignificanteffectsontemperatureextremes

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sintheexperiments,andimpactsonprecipitationextremesarealsoidentified.Casestudiesofselectedmajorsummerheatwavesrevealthattheintraseasonalandinterannualvariabilityofsoilmoistureaccountfor5–30%and10–40%ofthesimu-latedheatwaveanomaly, respectively. Inaddition, isalso found that soilmoisturehasa significanteffectonheatwavepersistencethroughsoilmoisturememory.Forextremeprecipitationeventsontheotherhand,onlythewetdayfrequencyisimpactedintheexperimentswithprescribedsoilmoisture.

Finally,trendsinclimateextremesincurrentclimate-changeprojections,suchasanincreaseintemperatureoverthewholeEuropeancontinent,aswellasaSouthernEuropeandecreaseandNorthernEuropeanincreaseinprecipitationextremes,canalreadybedetectedinsimulationsforthepastdecades,andappearatleastpartlylinkedtosoilmoisture-atmospherefeedbacks.

1.23

Swissrivers.ch – Online river forecast prediction

JordanFrédéric*,ClaudePhiliponna**,HellerPhilippe*

*e-dric.ch eau énergie environnement, Le Grand-chemin 73, CH-1066 EPALINGES (fred.jordan@e-dric.ch)**Camptocamp SA, PSE A, EPFL, CH-1015 LAUSANNE

Dischargepredictioninriverbasinshasbecomeapluridisciplinaryandhigh-technologytopic.Theneedsforsuchsystemsarerelatedtofloodmanagement,hydroelectricitymarketorleisureactivities.Inthiscontext,swissrivers.chhasbeendeve-lopedtoprovideeveryone,usinginternet,informationaboutthefuturedischargeinallthemainriversofSwitzerland.

Figure1.Thenewwebplatformwww.swissrivers.ch,withadirectgeographicalaccesstoriverdischargepredictions.

Thenewonlineplatformworksasfollows:numericalweatherpredictionsareprovidedbytheFederalOfficeforMeteorologyandClimatology(Meteoswiss),twiceadayandupto72hoursahead.TheirprecipitationandtemperaturepredictionsissuedfromtheCOSMO-7model(Schättler,Barbu,2008)witha6.6kmhorizontalgridmeshareusedforanextractoverthewholecountrytocalculatethepredicteddischargesinthesub-basinsandintherivers.Inordertooptimizethequalityofthepre-dicteddischarges,thehydrologicalmodelisupdated4timesaday:thecontinuoussimulationisautomaticallymodifiedbycomparisonbetweendischargemeasurementsandcomputeddischargesbasedonmeteorologicalobservationsoverthelast24hoursforeachoneofthe280automaticfederalgaugingstationsofSwitzerland(BAFU).Theobjectiveofthismodelupdateistoensurethatthemodelalwayssimulatesrealisticdischargesinrivers.

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es Theinformationprovidedbyswissrivers.chcanbefreelyaccessedfor2500sub-basinsand1500locationsintheswissrivers.

Foreveryselectedlocation,theupdatedsimulationofthelast24h,aswellasthedischargepredictionforthenext30hoursarepresentedasaplot.

ThesystemisbasedontheRS3.0technology,whichallowstheautomaticdataacquisitionandstorageinadatabase(weatheranddischargeobservations,numericalweatherforecasts),therainfall-runoffsimulationincludingsnowmelt,glaciermelt,evaporation, infiltration, surface runoff, river routing aswell as flow routing in hydraulic structures (reservoirs, powerplants,waterdiversions,etc…).RS3.0alsoallowsanautomaticpublicationoftheresultsinawebplatformorinaGIS.Thistechnology is based on previous developments realized for theMINERVE Project at the Ecole Polytechnique Fédérale deLausanne(Jordanetal.,2007,Garciaetal.,2008,Jordanetal.,2008).

Theperformanceofthesystemhasbeenoptimizedbyacalibration-validationprocedureusingmorethan15yearsofhour-lydata,over300controlpointsinSwitzerland.However,themodelcouldbeimprovedbyintegrationofnewhistoricalandreal-timecontrolpoints,inbasinslocatedupstreamoflargedamsandreservoirs.

REFERENCESGarcia, J., Jordan, F.,Dubois, J.&Boillat, J.-L. 2007: "RoutingSystem II,Modélisationd’écoulementsdansdes systèmes

hydrauliques",CommunicationLCHn°32,Ed.Prof.A.Schleiss,LausanneJordan, F. 2007: "Modèle de prévision et de gestion des crues - Optimisation des opérations des aménagements

hydroélectriquesàaccumulationpourlaréductiondesdébitsdecrue",Thèsededoctoratn°3711,EcolePolytechniqueFédéraledeLausanne.

Jordan,F.,GarciaHernandez,J.,Dubois,J.&Boillat,J.-L.2008:"MINERVE:ModélisationdesIntempériesdeNatureExtrêmeduRhôneValaisanetdeleursEffets",CommunicationLCHn°38,ed.A.Schleiss,EPFL,Lausanne

Martinerie, R. 2009: Numerical Modelling of Stormwater andWastewater Conveyance System of Lausanne City(Switzerland),Proc.,WaterEngineeringforaSustainableEnvironment,33rdIAHRCongress,Vancover,Canada

Schättler,U.,Barbu,C.2008:COSMO-NewsletterNo.9.pp.87.availablethrough:www.cosmo-model.org>Documentation>Newsletters.PrintedatDeutscherWetterdienst,OffenbachamMain,Germany

1.24

The influence of climate change on the water balance of mesoscale catchments in Switzerland

KöplinNina*,**,ViviroliDaniel*,**,WeingartnerRolf*,**

*Institute of Geography, University of Bern, Hallerstrasse 12, CH-3012 Bern (nina.koeplin@giub.unibe.ch)**Oeschger Centre for Climate Change Research, University of Bern, Zähringerstrasse 25, CH-3012 Bern

RecentresearchshowsthattheanticipatedclimatechangeinSwitzerlandwillresultinchangingprecipitationpatternsandincreasingtemperaturesduringthefirsthalfofthe21stcentury.Amongstothers,thetemperatureincreasewillcauseanupwardshiftofthesnowline,andprecipitationwillfallmoreoftenasrainthanassnow.Thecombinationofthesechangeswillprovokeachangeintherunoffregimesuchasanearlieryearlypeakflow.Whileevapotranspirationwillgenerallyin-creaseinafutureclimate,thechangesinprecipitationamountswilldifferseasonally,withincreasesinwinteranddecreasesinsummer(OcCC2007).Theyearlyvolumeofdischargeislikelytodecreasewiththeexceptionofalpinecatchmentswhereglacierswillfunctionasreservoirsduringthenextyears(Schädler2008).

Ourmaininterest lies inthequestionwhenandinparticularwherethesystemstartstippingoverandabovementionedchangesshowthroughinthehydrologicalresponseofcatchments.Thisissuewillbeaddressedintheframeworkofthejointresearchproject“ClimateChangeinSwitzerland–Hydrology”(CCHydro)whichwasinitiatedbytheFederalOfficefortheEnvironment(FOEN)andseekstoassesspossibleeffectsofclimatechangeonhydrologicalsystemsinSwitzerland.Thehete-rogeneityofcomplexmountainouslandscapes,however,forbidsgeneralstatements.Therefore,amultidisciplinaryandho-listicapproachwaschosenandthescenariosinuseareofhightemporalandspatialresolution.

Asafirststep,hydrologicalmodellingisusedtoidentifyandexaminecatchmentsthatexhibitsensitivitytowardsachangeinclimate.Forthis,weusetheprocess-orientedhydrologicalmodellingsystemPREVAH(Vivirolietal.2007).Themesoscalecatchmentsunderinvestigationhaveameanareaofabout150km2.Aftercalibrationofthecatchmentsforwhichmeasured

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sdischargerecordsareavailable,aregionalisationscheme(Viviroli2007)isusedtoarriveatacomprehensivesetofmodelparametersfortheentireareaofSwitzerland.Spatiallyandtemporallyhighlyresolvedscenariosoftheprojectedclimatechangeuntil2050willthenbeusedtoforcethemodel.ThescenarioswillbescaleddowntostationdatabytheInstituteforAtmosphericandClimateScience(IAC)atETHZurichusingtheDeltaApproach.

Asaresult,regionsexhibitingclimatesensitivityintheperiod2021to2050willbespecified,andpossiblecausalrelation-shipsbetweensensitivityandspecificcatchmentcharacteristicswillbeevaluated.

REFERENCESOcCC2007:KlimaänderungunddieSchweiz2050.ErwarteteAuswirkungenaufUmwelt,GesellschaftundWirtschaft.Bern:

OcCC.Schädler,B.2008:Klimawandel-GehtunsdasWasseraus?,GasWasserAbwasser,10,763–769.Viviroli,D. 2007: EinprozessorientiertesModellsystemzur Ermittlung seltenerHochwasserabflüsse fürungemessene

EinzugsgebietederSchweiz.GeographicaBernensiaG77.Bern:GeographischesInstitutderUniversitätBern.Viviroli,D.,Gurtz, J.&Zappa,M. 2007: TheHydrologicalModelling SystemPREVAH.GeographicaBernensia P40. Bern:

GeographischesInstitutderUniversitätBern.

1.25

Palaeoenvironmental mapping of the Swiss Rhone river

LaigreLaetitia*,Arnaud-FassettaGilles**,ReynardEmmanuel*

* Institut de Géographie, Université de Lausanne, Anthropole, CH-1015 Lausanne (laetitia.laigre@unil.ch)** Département de Géographie, Université Val-de-Marne (Paris 12), Avenue du Général de Gaulle 61, F-94010 Créteil Cedex

AsmanyEuropeanrivers,theSwissRhoneriveranditsfloodplainhaveknownseveralmorphologicalvariationsaftertheLittleIceAgethatendedaround1850.BasedontheconceptofthepalaeoenvironmentalatlasbuiltontheFrenchRhoneriverbyJ.-P.Bravardetal. (2008),palaeoenvironmentalmappinghasbeencarriedoutintheSwissRhoneriverwatershed(Laigre2009).Comparisonofhistoricalmapsfrom1835to1996(Dufourmap,SiegfriedAtlas,andseveraleditionsofnationalmapofSwitzerland)showsseveraleventsoffluvialmetamorphosis(Bravard1989)ofthechannel.Untilthe1860’s,numerousgravelbars,extensiveislandsandlargeactivezonecanbeobserved.Thebraidedstyleisthedominantfluvialpattern.Sincetheendofthe19thcentury,mostofchannelsarestraight,exceptedonearea–theFingesForestzone–wherealargepartofthevalleyisoccupiedbyanimportantbraidedsystem.Sincethe1940’s,achannelconstrictionisobservedaswellandinci-sionofthepresentstraightchannelisprogressing.

Analysisof themetamorphosis factorsemphasisesprincipallyoneexternalvariable,whichmodified the system:humanintervention.ChannelizationoftheRhoneriveranditstributariesfromthelate19thcenturyandgravelextractionshavecompletelymodified thenatural sedimentary functioning andbalance, in a period of reduced sedimentary supply thatcharacterisestheendoftheLittleIceAge.Moreover,morphologicalmodificationsofthefluvialsystemhadimpactsonthefloodplainlandscapeevolutionandlanduseinthevalley,whichwascharacterisedbylargewoodlandandwetlandareasuntiltheendof19thcentury.Understandingfunctioningofpastenvironmentsmaybeaprecioushelptoanticipateeventu-alfuturefloodeventsthatcauselargedamagesintheAlpinerange.

REFERENCESBravard,J.-P.1989:LamétamorphosedesrivièresdesAlpesfrançaisesàlafinduMoyen-Ageetàl’époquemoderne,Bull.Soc.

Géogr.Liège,25,145-157.BravardJ.-P.,ProvansalM.,Arnaud-FassettaG.,ChabbertS.,GaydouP.,DufourS.,RichardF.,ValleteauS.,MelunG.&PassyP.

2008:Unatlasdupaléo-environnementdelaplainealluvialeduRhône,delafrontièresuisseàlamer.InDesmetM.,MagnyM.,MocciF. (coord.).Duclimatàl’Homme.Dynamiqueholocènedel’environnementdansleJuraetlesAlpes,CollectionduLaboratoireEDYTEM,CahiersdePaléoenvironnement6,101-116.

Laigre L. 2009: Etude diachronique de la dynamique fluviale duRhône suisse depuis la fin du Petit AgeGlaciaire –Cartographiepaléoenvironnementale sectoriellede la source au lac Léman,MémoiredeMaster,Université Paris 1-Panthéon-Sorbonne.

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Storage and release of water and chemical species in glaciers

MartinLüthi

Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie (VAW), ETH Zürich, 8092 Zürich (luethi@vaw.baug.ethz.ch)

Glaciersaccumulate solidprecipitation in formof ice, andwith itmaterials ranging fromchemical species todustandstones.Onlyundersteadyclimateconditionsthereleaserateofthesematerials,andwater,isconstant.Underavaryingcli-matethereexistcoldperiodswithreducedreleaseofaccumulatedwaterandchemicalspecies,aswellaswarmperiodswhenwaterisreleasedathighrate.Duringthewarmperiods,highconcentrationsofchemicalsandsedimentsarereleasedfromtheglacier.Wepresentresultsfromatransientflowlinemodelofaglacierwhichallowsustoquantifytheseprocesses.InacasestudyonOberaargletscherweshowthatpersistentorganicpollutants(POPs)emittedtotheatmosphereinthe1950-1960swerestoredintheglacierandarereleasedathighrateduringthelastdecade.Consequently,theconcentrationoftoxicPOPsintheproglaciallakeareashighasduringthetimeofatmosphericimpact,whichagreeswithmeasurementsinasedimentcore.

1.27

Groundwater and tunneling: implementation of a geochemical monito-ring network in the southern Switzerland

MarzocchiRoberto*&PeraSebastian*

* IST – SUPSI Istituto scienze della Terra, CP 72, CH-6952 Canobbio (roberto.marzocchi@supsi.ch)

Theinteractionoftunnelingwithgroundwaterisaproblemfromtheenvironmentalaswellastheengineeringpointofview.Infact,tunneldrillingmaycauseadrawdownofpiezometriclevelsandinflowsintunnelscanbeaproblemduringexcavationsteps.Infracturedrockwatercirculationisstronglyinfluencedbystructuralelements,suchasfaultzones,frac-turesandotherdiscontinuities,andnumericalsolutionsarefrequentlyusedinliterature(NAGRAsince1985,Ofterdingeretal1999,Löwetal.2007).Tothispurposevariousconceptualapproacheshasbeenperformedtodescribeandmodelthegroundwaterflowthroughfracturedrockmasses,rangingfromequivalentcontinuummodelstodiscretefracturenetworksimulationmodels.Howevertheirapplicationneedsmanypreliminaryinvestigationsonthebehaviorofthegroundwatersystem;moreoverthesemodelsrequestacorrectcalibration,thatisverycomplex,evenimpossiblewithoutacollectionofnecessarystructuralandhydrochemicaldata.To study large-scale flowsystems in fractured rocksofmountainous terrains, a comprehensive study isongoingclose toLuganousingthedataproducedinoneofthemaininfrastructuresactuallyinconstruction,theAlptransitMonteCeneribasetunnel.Themaingoalofthisworkistheunderstandingofhowthecollectionofisotopicandgeochemicaldata,andgeophysical techniques (VLFprofilesand2Dresistivity surveys), combiningwith structuralandhydrogeological informa-tions,canbeusedinordertodevelophydrogeologicalconceptualandperhapsnumericalmodels.In theregionsurroundingtheMonteCeneribase tunnel thereareabout750springsactuallyregistered inthecantonaldatabase.Onthebasisofcriteriaof(i)relevance(useanddischarge)and(ii) distancefromthetunnel,anumberofspringsarebeselectedformonthlymeasurementsofdischarge,electricconductivity,pH,andtemperature,andwatersamplesaretakingtomonitorstableisotopesofhydrogenandoxygen(2H,18O)andtritium(3H),perhapscombinedwithhelium-3.Furthermorethesedatawillbecomparedwithtunnelinflowsinformationstoperform,withinreason,avalidationofthemodelthatwillbedesignedtakingadvantagesofthesetechniques.Inparticular,theanalysisofstableisotopecompositionofsprings,willreflecttheirwaterorigin,becausespatial(rechargealtitude,topography,etc.)andtemporal(seasonal)effectsinprecipitationsstronglyaffecttheisotopiccompositionofmete-orologicalwaterandconsequentlyofgroundwaterreservoirs(fig.1).Theanalysisoftritium,thatisaradioactiveisotope,willbeusedforgroundwaterdating(fig.2);usingonlytritiumwewillobtainaqualitativeindicationofwaterage(youngoroldgroundwater),whiletritiumcombinedwithhelium-3,incaseofmodernwater,willprovideus,a“discreteage”forthesam-pledwater.

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Figure1.Stableisotopesfractionation:physicalprocessesandrelevantregisteredeffects.

Figure2.Basicprinciplesofthedatingmethodswithtritium.Onthelefttheregisteredtritiumconcentrationduringlastdecades,thatal-

lowstoqualitativedistinctionbetweenyoungandoldgroundwaters.Ontherighttheusingoftritiumcombinedwithhelium-3.

REFERENCESAA.VV.1985.Grimseltestsite–Overviewandtestprograms,NAGRAtechnicalreport85-46Löw,S.,Lützenkirchen,V.,Ofterdinger,U.S.,Zangler,C.,Eberhardt,E.&Evans,K.2001.Environmentalimpactsoftunnelsin

fracturedcrystallinerocksoftheCentralAlps,IAHSelectedPapers,Vol.9,Chapter34,507-526Ofterdinger,U.S.2001.GroundwaterflowsystemsintheRotondoGranite,CentralAlps(Switzerland),PhdthesisofNatural

Science,Swissfederalinstituteoftechnology(ETH)–Zurich

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Dynamics of colloid concentrations in a small river related to hydrological conditions and land use.

MBockPatrick&LoizeauJean-Luc

Institut F.-A. Forel, Faculté des sciences, Université de Genève, Route de Suisse 10, CH-1290 Versoix (Jean-Luc.Loizeau@unige.ch)

Colloidsplayamajorroleinthetransportandbioavailabilityofcontaminantsinaquaticenvironments.Theirdynamicsinanecosystem(erosion,transport,aggregationandsubsequentsettling)isakeyparametertounderstandthefateandpoten-tialimpactsofcolloid-associatedpollutantssuchasmetalsororganicpollutants(e.g.Benoitetal.1994,Irace-GuigandandAaron2003).Inriversystems,colloidalparticlesaremainlyofdetritaloriginandderivedfromtheerosionofsoilsandim-permeablesurfacesinthewatershed.

Inthepresentstudy,thewatershedoftheVersoixRiver(France,Switzerland),atributaryofLakeGeneva,hasbeeninvesti-gatedbysamplingwateratdifferentsitesalongtherivercourse,andundervarioushydrologicalconditions(lowflows,snowmelting,smallfloods).Thewatershedmaincharacteristics(slope,landuse)havebeendeterminedateachsamplingpointandquantifiedthroughaGIS-basedstudy.Colloidandparticlenumberandsizedistributionshavebeenmeasuredintherange0.05–20µmusingasingleparticlecounter(RosséandLoizeau2003).

Resultsshowthatthesizedistributions(expressedinnumberofparticles)followapowerlaw,withverysimilarslopes,in-dependentlyoftheconcentration.Attherivermouth,colloidconcentrationsduringsmallfloodconditionswere10to100timeshigherthanduringlowflows,whilesuspendedmatterwasonly2to3timeshigher,andthedischargeincreasedjustbyafactortwo.Theselargediscrepanciesintheamplificationfactorsbetweensuspendedparticlesandcolloidsconcentra-tionsreflectthepreferentialmobilizationofeasyerodiblecolloidalparticlesduringrainevents.Inaddition,colloidconcen-trationsalsogenerallyincreasewiththedistancefromtheheadwaters,forbothhighandlowflows.Thislikelyreflectsacontinuouscolloidsourcefromtheriverbeditself.Howeversomevariationsexistinthecolloidconcentrationthatmayberelated todifferences in the land cover. TheVersoixRiverwatershed is complex, comprising forest,meadows, cultivatedfields,industrialandurbansurfaces,andwetlands.Acarefulexaminationofthecolloidconcentrationevolutionalongtherivercourseduringraineventsshowsthatproportionofurbansurfacesandcultivatedfieldarepositivelycorrelatedtoin-creasedcolloidconcentrationsintheriver.

Asthecapacityofcolloidalparticlestoscavengeandsubsequentlytransportcontaminantislargelyrelatedtotheirspecificsurface,thelargeincreaseofcolloidconcentrationsduringfloodimpliesamuchlargerpotentialcontaminantloadtothereceivingwaterbodythanthatgenerallyobservedwithpollutantinputsrelatedtosuspendedparticlematter.

REFERENCESIrace-Guigand, S,and Aaron JJ, 2003. The roleoforganic colloids inherbicide transfer to rivers: aquantitative studyof

triazineandphenylureainteractionswithcolloids.AnalyticalandBioanalyticalchemistry,376:431-435.Benoit,S.D.,Oktay-Marshall,A.Cantu,E.M.Hood,C.H.Coleman,M.O.CorapciogluandP.H.Santschi,1994.Partitioningof

Cu,Pb,Ag,Zn, Fe,Al, andMnbetween filter-retainedparticles, colloids, and solution in sixTexas estuaries,MarineChemistry45:307–336

Rossé,P.,andJ.-L.Loizeau,2003.Useofsingleparticlesingleparticlecountersforthedeterminationofnumberandsizedistributionofcolloidinnaturalsurfacewaters.ColloidsandSurfacesA217:109-120.

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Water disturbance as the organizer of riparian vegetation

MolnarPeter*,PeronaPaolo*,BurlandoPaolo*

*Institute of Environmental Engineering, ETH Zürich, CH-8093 Zürich (molnar@ifu.baug.ethz.ch, perona@ifu.baug.ethz.ch, paolo.burlan-do@ethz.ch)

Theflowregimeplaysanimportantrole intheorganizationofriparianvegetationinnaturalriversbycreatingsuitablegerminationsites,erodingplantsandchangingtherivermorphology.Animportantaspectoftheflowregimeisthedistur-banceelement,i.e.theseasonaldistribution,timingandmagnitudeoffloods.Theinteractionsbetweenwater,sediment,andriparianvegetationaremostevident innaturalunregulatedrivers, suchasgravel-bedbraidedstreamsandsand-bedmeanderingrivers.Restorationprojectsinregulatedriversoftenaimtomakeroomforthesenaturalinteractionstotakeplace.Thereforeweneedtocontinuouslyimprovethescientificbasistounderstandthefundamentalwater-sediment-vege-tationinteractionsanddevelopnewtoolsandmethodstosimulateandtest them. Inthispaperwepresenttwonewap-proaches(numericalandlaboratory-based)whichwearedevelopinginourgroupandwhichlookatwaterdisturbanceasanorganizingelementofriparianvegetation.

Thefirstnumericalapproachisastochasticmodelforwater-sediment-vegetationinteractionsinabraidedgravel-bedstream.Thisisanapproachthatmodelstheexpansionandcontractionoftheexposedsedimentareainabraidedriverdrivenbystochasticflooddisturbancesandbyadeterministiccolonizationoftheexposedsedimentbanksandbarsbyriparianvege-tationinthetimebetweenthefloods.Thebasicmodelallowsustodevelopananalyticalsolutionfortheprobabilitydensi-tyfunctionoftheexposedsedimentareaasafunctionoftheflooddisturbanceparametersandvegetationgrowthrate(Fig1)(Peronaetal.,2009).

stochastic disturbance termflood mortality

( )swsw sw G

dAA A C

dt= Θ ∆ ⋅∆ −

pdf of disturbances

pdf of thesedimentarea

pdf of disturbances

pdf of thesedimentarea

pdf of disturbances

pdf of thesedimentarea

G G swC k A=0( , ) ( ) ( , ) ( )

f

at c atsw sw Ag A t g t g A t g t= + +

deterministic growth termcolonization by vegetation

Figure1.SetupoftheprocessequationfortheexposedsedimentareaAswandanillustrationofthesolutionforthepdfofA

sw.

Thissimplemodelmaybeextendedtoincludesuccessivevegetationstagesandtheircompetitionforavailablespaceonthefloodplain(Peronaetal.,2008).

Thesecondlaboratoryapproachisanexperimentwhichstudiestheroleofhydrologicaldisturbancesonbiomasserosiondynamics in a sand-bed flume which is seeded by a fast growing grass. This experiment was conducted at the TotalEnvironmentSimulatoroftheUniversityofHullundertheHydralab3EUProgramme(Molnaretal.,2009,inpreparation).Intheexperimentwestudiedtheinteractionsbetweenthedisturbancesandthegrowthrateofthevegetationrootsandstems.Preliminaryresultsshowthattheactionoffluvialerosionremovessystematicallyplantsthatarenotabletowith-standtheappliedstress,whilethenon-erodedcommunitycontinuestogrowanddevelop(Fig2).

Thetwopresentedapproachesbothillustratethatthewaterdisturbanceregimeplaysanimportantroleintheorganizationofbraidedrivermorphologiesandsandbedstreams,riparianvegetation,andplantcommunities.Thewaterdisturbanceregimeandvegetationgrowthinteractandresultinadynamicripariancommunity.Weadvocatethatthisisnotadetermi-nisticproblemandthattheeffectofwater-sediment-riparianvegetationinteractionsshouldbeexaminedinaprobabilisticframeworkbothatalargefieldandsmalllaboratoryscale.

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Figure2.Exampleofasimulationrunwiththehistogramsofthenumberofroots(top),lengthofthemainroot(center)andstemheight

(bottom)forerodedandnon-erodedplants.

REFERENCESPerona,P.,P.Molnar,M.Savina,andP.Burlando(2008).Stochasticsediment-vegetationdynamicsinanAlpinebraidedriver,

IAHSPubl.325,266-274.Perona,P.,P.Molnar,M.Savina,andP.Burlando(2009).Anobservation-basedstochasticmodelforsedimentandvegetation

dynamicsinthefloodplainofanAlpinebraidedriver,WaterResour.Res.,doi:10.1029/2008WR007550.

1.30

Calculating bedload transport rates in Swiss mountain streams using new roughness approaches

ManuelNitsche*,AlexandreBadoux*,JensM.Turowski*,DieterRickenmann*

*Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zuercherstrasse 111, 8903 Birmensdorf, Switzerland (nitsche@wsl.ch)

Mostmethodsforpredictingbedloadtransportdonottakeintoaccounttypicalroughnesselementsofsmall,steepmoun-tainstreams,likestep-poolsequences,largebouldersorwoodydebris.However,flowresistanceduetosuchformroughnesselementsappearstobeanimportantcontrolonbedloadtransportratesinmountainstreams.

Recently,newapproachesbasedonlaboratoryexperimentswereproposedtoassessflowresistanceduetoformroughness.Theyquantifytheeffectsofgeneralizedmodelsofroughnesselementstoflowresistance.Furthermore,severalempiricallyderivedformulaetocalculatebedloadtransportratesincludingarespectiveroughnessparameterhavebeenpublished.

Theobjectiveofourstudyistosystematicallytesttheseapproacheswithfieldobservations.Forthispurpose,wemeasuredthe required roughnessparameters for sevenSwissmountain streams,with local channelgradients ranging from1.5 to16.5%,andcatchmentareasfrom12to43km2.Wecalculatedflowresistanceandbedloadtransportforsedimenttransportevents in2000and2005.Bycomparingcalculatedandobserveddataofbedloadtransportwe identifiedwhetherand inwhichrangetheexaminedapproachesaresuitableforapplicationinnaturalstreamconditions.

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Pollution des eaux: la santé est-elle un levier pour mettre en place une gestion intégrée à l’échelle du basin versant?

NiwaNelly*,RossiLuca**&ChèvreNathalie***

* IPTEH - Faculté des Géosciences et de l’Environnement, Université de Lausanne, CH-1015 Lausanne (nelly. niwa@unil.ch)**IIE-ECOL, ENAC, EPFL, CH-1015 Lausanne (luca.rossi@epfl.ch)*** IMG - Faculté des Géosciences et de l’Environnement, Université de Lausanne, CH-1015 Lausanne (nathalie.chevre@unil.ch)

Laproblématiquedespolluantscommelespesticides,médicaments,cosmétiques,dansleseauxdesurfaceestdeplusenplusactuelle.Nonpasque cesmicropolluants soientdes substancesnouvelles,maisplutôtque les techniquesd’analysechimiqueseperfectionnant,ondécouvredeplusenplusdesubstanceschimiquesdanslemilieuaquatique.Ilsembleéga-lementquecessubstancesnesoientpassansconséquencessur l’hommeet l’environnementpuisqu’onleurattribuedeseffetscancérigènesoudediminutiondelafertilité.

Dansuneoptiquedegestiondurabledesressourceseneau,ilestdoncindispensabledeprendreencomptel’aspectdesmi-cropolluants.Cependant,cettepollutionesttrèsdifficileàmaîtrisercarellen’estpasconfinéedansunendroitclos.Lessubstances sont souvent transportées surde longuesdistances et peuvent ainsi engendrerdes effets loinde leur sourced’émission.Atitred’exemple,desrejetsindustrielsdansleValaisontconduitàunecontaminationduLémanparcertainspesticidesetmédicamentsquiseretrouvaientensuitedansleseauxbrutesdesstationsdepompageautourduLéman.Cettepollutionestaussidifficileàlimitercarsidesquotaspeuventêtresdéfinisparsecteurs,lasommeglobaledessubstancesdetous les secteurspeutvitedonner lieuàunepollutionayantdes conséquences importantes sur l’environnement.Enfin,cettepollutionestcomplexecarl’associationentredifférentessubstancespeutaussidonnerlieuàdescocktailsdétonants.

Pourminimiserlerisquepourl’hommeetl’environnementdesmicropolluants,ilestdoncindispensabledepasseràunegestion«intégrée»del’eauquiprenneencomptelesacteursetleurorganisationàuneéchellerégionale.Autraversd’unjeuderôleorganisédanslecadred’uneformationpost-grade,nousavonstentéd’explorercommentlasantépourraitêtre(ounepasêtre)unlevierpourmettreenplacecettegestionintégréeetenquoicelapourraitconduireàrevisiterlespratiquesdel’aménagementduterritoire.

Labrèveanalysequenousavonsmenédujeuderôlesnouspermetdemettreenexerguetroisconclusionsprincipales:Lapremière,c’estquelasantéestunlevierparticulièrementpertinentpourdéclencheruneprisedeconscienceduproblèmeetpermetd’amorcerdefaçontrèsrapideunedémarchevisantàlerésoudre.Encela,lasantésembleêtreunélémentdé-clencheuretcatalyseurduprocessus.

Laseconde,c’estquelasantéestunthèmesensibledontilesttrèsdifficilededétermineretd’assumerlaresponsabilité.Pourautant,cettecomplexitéengendreaussilaprisedeconsciencedelanécessitéedemettreenplaceunprocessuscollec-tif.Lasantépermetdoncderassembleretdedynamiserunedémarchecollective,globaleetintégrée.

Enfin,latroisième,c’estqueleprocessusentiernepeutentièrementreposersurl’argumentdelasanté.Eneffet,ilsemblequelasanté,mêmesiellereprésenteunenjeufort,peutêtreviteenconcurrenceavecd’autresenjeux,particulièrementaveclesenjeuxéconomiques.Ilenrésultealorssouventlamiseenplacedesolutionsréduites,«endofpipe»,quinecorres-pondentplusàl’objectifdedépart,àsavoir:unesolutionglobaleetintégrée.

Pourconclure,ilnousparaitimportantdesoulignerànouveauquesilejeuderôleestunoutiltrèsintéressantpouranaly-serdesprocessus,ilneremplaceenaucuncasl’étudedecasréels.Eneffet,ils’agitd’unesituationsimplifiée,accéléréedansletempsetavecdesacteursfactices.Néanmoins,ilestintéressantdeconstaterquelessituationsdécritesdanslejeuderôlesseretrouventsouventdansdescasréels.

REFERENCESEdderP,OrtelliD,andRamseierS,2006:Métauxetmicropolluantsorganiques.Rapp.Comm.int.prot.eauxLémancontre

pollut.Campagne2005.CIPEL(CommissionpourlaprotectiondeseauxduLéman):Lausanne.p.65-87.NiwaN,RossiL,ChèvreN.Micropolluantsdansleseaux: lasantesera-t-elleunleviersuffisantpourmettreenplaceune

gestionintégrée?.ChapitredelivreCEAT.Aparaître.

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Effective stress and fracture permeability in regional groundwater flow: numerical comparison of analytical formulas

PreisigGiona*&PerrochetPierre

*Centre of Hydrogeology, Emile-Argand 11, CH-2009 Neuchâtel (giona.preisig@unine.ch)

Thedependencyoffracturepermeabilityoneffectivestressisasubjectwellknownandhasbeenintensivelystudiedlastdecades.Inregionalanddeepgroundwaterflowsystemundergrounddrainingstructuresastunnels,causeadiminutionofporepressureleadingtoanincreasingeffectivestressandadecreasingpermeability.Oneapproachconsiststoinsertconsti-tutive laws relating effective stress topermeability inDarcy’s law,which isused to evaluate 3D regional simulations ofdischargerates,pressuredistributionsand flowpaths.Thisapproachgain inaccuracyascompared to theclassicaloneswhichconsiderconstantpermeabilityfield.However,thetypeandparameterizationoftheconstitutivelawinfluencethefinalresult.

Inthiswork,threedifferentmodelfunctionsrelatingeffectivestresstopermeabilityareimplementedinthetensorformofDarcy’s law,andcomparedbymeansofnumericalexperiments.Twoof these functionswerederivedfromexperimentalworks (Louis1969;Walsh1981), theotheronewastheoreticallyderivedfromHooke’s law.Numericalsimulationsareallbasedonaninitialfracturedhydrostaticsystemwhereanundergrounddrainingstructureisactivated,causingasteady-statesaturatedflowfromtheupperboundarycondition(surface)tothelowerboundarycondition(undergroundstructure).Thegoverningnonlinearequationsaresolvedusingthefiniteelementmethod.

Inthethreecases,resultsshowthattheintroductionofstress-dependentpermeabilitiesinDarcy’slawleadstodischargeratessignificantlylowerthanthosecalculatedwiththeclassicalapproach.Thisis explainedbyadecreasingpermeabilityduetoanincreasingeffectivestress,particularlyinthevicinityofthedeepdrainingstructure. Louis’experimentalmodelyieldsthelargestdifferenceandhasthedeficiencyofnotconsideringtheverticalstressterm,whileWalsh’smodelisdiffi-culttosolvenumericallyduetohigherordernonlinearities.Theelasto-statisticalmodelanalyticallyderivedfromHooke’slawseemstobebetteradaptedforsolvingsuchproblemsandyieldsdifferenceswhicharesomewhatsmallerthanthetwoothers.

REFERENCESLouisC. 1969:A studyof groundwater flow in jointed rockand its influenceon the stabilityof rockmasses. Technical

ReportNo10,9/69,RockMechanics,ImperialCollege,UK.Walsh J.B. 1981: Effect of pore pressure and confiningpressure on fracture permeability. Int. J. RockMech.Min. Sci.

Geomech.Abstr.,18:429–435.

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Debris flows, landslides, and sediment transport in mountain catchments

RickenmannDieter*

*SwissFederalResearchInstituteWSL,Zürcherstrasse111,CH-8903Birmensdorf(rickenmann@wsl.ch)

Inmountainheadwatercatchmentswithsteepchannelsandhillslopes,floodsareoftenassociatedwithsedimenttransportand/orwithdebrisflows.Possibleinteractionsbetweendebrisflows,shallowlandslidesandfluvialsedimenttransportinsteepstreamsareillustratedFigure1.Theseprocessesoftenoccurduringhigh-intensityorlong-durationrainstorms,possiblycombinedwithsnowmelt,resultinginslopeinstabilities,sedimenttransportingflowsandfloods.Theseprocessesareoftenassociatedwithdamagetohousesorinfrastructure,particularlyalongthechannelnetwork,andmayinvolvealsocasual-ties.

Debrisflowstypicallyoccurinsteepheadwatercatchments.Atorrentcatchmentischaracterisedbysporadicandsuddenhighdischargesofbothwaterandsediments,andittypicallycomprisesacatchmentarealessthanabout25km2.Thechan-nelgradientmayvaryfrommorethan60%toafew%inthefanarea.Thetorrentsystemanddebris-flowoccurrencecanbecharacterisedbythreemainzones:Theheadwaterareaorinitiationzonewheretheflowistriggered,thetransitzone(gullyandchannels)whereentrainmentofmoresolidmaterialmayoccur,andthedebrisfanareawhereoftenmajordepo-sitiontakesplace.DebrisflowsintheAlpsmayinvolvetotalsedimentvolumesofuptosomehundredthousandcubicme-tres.Thesedimentmaybesuppliedfrompointsourcessuchaslandslidesorfromincisionofthetorrentbedbyverticalandlateralerosion.Thetotaleventmagnitudeisoftenusedasaroughindicationtocharacterisetheintensityofadebrisflow.Thisparameterlargelyinfluencestheflowbehaviourinthechanneland–inthecaseofovertopping-theextentoftheaf-fectedareasonthefan.Debrisflowsmaydeliverimportantquantitiesofsedimenttothereceivingmountainriver.

Incontrasttolowlandgravelbedrivers,relativelyfewstudiesweremadeonsedimenttransportinsteepheadwaterchannels,withstreamgradientssteeperthanabout5%.Sedimenttransportdynamicsinthesechannelsmaybequitedifferentfromlow-gradientchannels.Thereisoftenastronginteractionbetweenhillslopeprocessesandthechannelnetwork.Sedimenttransportmaybesupplylimitedratherthancontrolledbythesedimenttransportcapacityforagivendischargeandchannelconditions.Steepheadwaterstreamsarecharacterisedbyawiderangeofsedimentsizesandtemporally-andspatially-vari-ablesedimentsources.Bedmorphologyandchannelstructuresmaybeinfluencedbythepresenceoflargeboulders,woodydebrisandbedrockconstrictions.Thiscanresultinlargevariationsinchannelgeometry,streamflowvelocityandrough-ness,andthustheapplicationoftheoreticalsedimenttransportequationsmaybeproblematic.Also,quantitativemeasure-mentsofsedimentandbedloadtransportinsteepstreamsareverylimited.

Inthispresentationanoverviewwillbegivenontheprocessesdebrisflows,shallowlandslidesandfluvialsedimenttrans-port.Aparticularfocuswillbethediscussionofinteractionsbetweentheseprocesses.Althoughanumberofmethodshavebeenproposedtopredictanddescribetheinitiationandflowbehaviourofdebrisflowsandsedimenttransportingflowsinmountainstreams,quantitativepredictionsforhazardassessmentarestilldifficultinmanycases.Theapplicationofsomemethodswillbeillustratedusingsomeexamplesfrompastfloodandrainstormevents.

B ed loadtrans port

Debrisflow

L ands lide

c hannel, low to medium inc lination

(≤ 15 . . . 30 %)

c hannel, medium to high inc lination

(≥ 15 . . . 30 %)

hill s lopes

F lood P rec ipitation

B ed loadtrans port

Debrisflow

L ands lide

c hannel, low to medium inc lination

(≤ 15 . . . 30 %)

c hannel, medium to high inc lination

(≥ 15 . . . 30 %)

hill s lopes

F lood P rec ipitation

Figure1:Occurrenceofdebrisflows,shallowlandslidesandfluvialsedimenttransportinsteepmountainstreams.

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Characterisation of geothermal reservoirs using 3D geological modelling and gravity

SchillEva*,AbdelfettahYassine*,AltweggPierrik*,BaillieuxPaul*

*Laboratoire de Géothermie - CREGE, Université de Neuchâtel, Rue Emile Argand 11, CH-2009, Neuchâtel, Suisse (paul.baillieux@unine.ch)

Theproductivityofgeothermalresourcesdependondifferentparametersmainlythereservoirtemperature,thehydraulicconductivityandthestressfield.Ithasbeenrealizedindifferentstudiesthatthehydraulicconductivityofthereservoiristhedominantfactor(e.g.BestPracticeHandbookfortheDevelopmentofUnconventionalGeothermalResourceswithaFocusonEnhancedGeothermalSystems,2008).Thisstudyispartofthelong-termresearchoftheLaboratoryofGeothermicsatNeuchâtelwiththeobjectivetodevelopamethodologytoinvestigatepermeabilityfromgeophysicalexploration.Theaimofthisstudyistodevelopamethodtocharacterizetheporosityfromgravityinversioncombinedwith3Dgeologicalmodel-ing.

Gravitymeasurementsprovideinformationonthedensityofsubsurfaceunitseitherbyforwardmodelingorinversion.Anditiswellknownthatthedensityofthesubsurfacecanbeeithercontrolledbylithologicalchangesorchangesinporosity(Pruis&Johnson1998).Furthermore,whenthegeologicalareaiswellknown,the3Dgravityinversioniswellconstraintsoitprovidesaccurateresultandbestdensitiesvaluesareobtained.Forporosity,oneamongtherelationshipswhichexistbe-tweenthedensityandporositycanbeused(e.g.Johnsonetal.,2000).

InthegeothermalareaofSoultzthecombinationof3Dgeologyandgravityinversionhasrevealeddensitychangesinthegraniticbasement(Figure1)whichcanberelatedtobothchangesinthegraniticfaciestotheNorthofthegeothermalsiteandtoporosityinthehorststructure,wherethereservoirislocated(Schill et al.,subm).SyntheticmodelsforotherdeepgeothermalreservoirssuchasSt.Gall(Switzerland)providefurtherindicationonthepossibilitiestodeduceporosityfromgravityforwardmodeling.TheexamplefromSoultzshows,however,thatonlyifthegeologicalstructuresarewellknownandcanbeassumedasfixinthegravityinversion,theestimationofdensitychangescausedbyporosityarepossible.

Figure1:MeandensitydistributionresultingfrominversionofgravitydataforarepresentativeE-Wprofileacrossthegeothermalreser-

voirofSoultz-sous-Forêts.(E-Wextension29km,altidudea.s.l.:-8000to250m).

REFERENCESSchill, E.,Geiermann, J.&Kümmeritz, J., subm.2-DMagnetotellurics andgravity at thegeothermal site at Soultz-sous-

Forêts.inWorldGeothermalCongress2010,pp.1390,Bali,Indonesia.Johnson, P.H., Pruis,M. J. & Van Patten,D.,Density and Porosity of theUpperOceanic Crust from SeafloorGravity

Measurements,Geophy.Res.Lett.27(7),1053-1056,2000.Pruis,M.P.&JohnsonH.P.,Porosityofveryyoungoceaniccrustfromseafloorgravitymeasurements,Geophys.Res.Lett.,

25,1959-1962,1998.

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s1.35

Field Fluorometer for Simultaneous Detection of 3 Colourless Tracers

SchneggPierre-André

Centre d'Hydrogéologie et de Géothermie CHYN, Rue Emile Argand 11, CH-2009 Neuchâtel (pierre.schnegg@unine.ch)

Wehavedesignedflow-throughfieldfluorometersforsimultaneousdetectionoftwoorthreeinvisible,colourlesstracers,sincethereisanincreasinginterestfor“blind”tracertests.

Althoughmostdyetracersusedinhydrogeologyareharmlesstotheenvironment(Behrensetal.2001,FOENReport2002)theirvisibleandindiscreetimpactonthepopulationremainsasourceofannoyanceforthefieldhydrogeologist.

Therecentappearanceofsmall,inexpensiveLEDsradiatingUVlightmadeitpossibletheexcitationofcolourlesstracersofthenaphthalenefamily.

Afewyearsago,companiescouldnotalwaysaffordmulti-tracertestsbecauselaboratoryexpensesincreasewiththenumberoftracers.Today,thankstothefieldfluorometer,multi-tracingistherule(SchneggandDoerfliger1997).However,asuccess-ful separationof tracers by the field fluorometerpresupposesdissimilar spectral characteristics of each tracer (Schnegg2003).Carefulselectionofthesetoftracersremainsmandatory.

Thefieldfluorometerconvenientlyreplacesthewatersampler.Withthisinstrumentthereisnoneedforfrequentsamplecollectionandsubsequentlaboratoryanalysisofthesamples.Veryhightimeresolutionisalsoofgreatinterest.However,theseparationoftwoorthreedifferentdyetracerscannotbeperformedattheresolutionachievableinthelaboratorywithaspectro-fluorometer.Theopticsofthefieldfluorometer ischaracterizedbypass-bandfilters.Toseparate2or3dyes inamulti-tracertest,thefluorometerrequiresasmanylightsources(usuallyLEDs)astracers,anddetectors.Eachopticalchan-nelisequippedwithadequateopticalfilters.Theunknownconcentrationsofeachtracerareobtainedbyresolvinginreal-timeasystemof2or3linearequations(Schnegg2003).

Foroptimaltracerseparation,thedeterminantofthesystemofequationsmustbeaslargeaspossible.Lowvaluesofthedeterminantindicateinadequateassociationoftracersofsimilarexcitation/emissionspectra.Forexample,thereisnochan-cetoseparateacocktailofrhodamineB,GorWT.Eventhesophisticatedlaboratoryinstrumentwillhavetroubleperformingtheseparation.

Mostfrequentlydyetracersusedare:Uranine,eosine,naphtionate,sulforhodamineB,amidorhodamineG,rhodamineWT,duasyne,tinopal,aminoGacid(Käss1998).Theproblemwithmostofthemisthevisualimpactinsurfaceordrinkingwater,particularlynear thepointof injection (disappearanceat concentrationsbelow10µg/L). Twoof them,naphtionateandaminoGacidaremuchmorediscreetintheenvironment.ThisisbecausetheirexcitationbandislocatedintheUVpartofthespectrum,andtheiremissionisclosetotheshortwavelengthlimitofvisiblelight.Afieldtestwascarriedoutinasurfacestream(100L/s)overadistanceof300metres.Yellowduasyne,athird,hardlyvisibletracer,wasusedjointlywiththetwoothertracers.Quantitiesof1and10mgofeachtracerwereinjectedinturnat2minutesinterval,sothatthebreakthroughcurveswouldoverlap,allowingthusfortestingtheseparationmethod.Thefigureshowsthethreebreakthroughcurvesaftermathematicalseparation.Asexpected,theydisplaythesameshapeandheight.Carefulcalibrationofthefluorometerisimportantforachievingperfectseparation.

REFERENCESBehrens,H.,Beims,U.,Dieter,H.,Dietze,G.,Eikmann,T.,Grummt,T.,Hanisch,H.,Henseling,H.,Käß,W.,Kerndorff,H.,

Leibundgut, C.,Müller-Wegener, U., Rönnefahrt, I., Scharenberg, B., Schleyer, R., Schloz,W., & Tilkes, F. 2001:Toxicological and ecotoxicological assessment ofwater tracers, Hydrogeology Journal 9, 321–325.DOI 10.1007/s100400100126.

FOEN,ArbeitsgruppeTracerderSchweizerischenGesellschaftfürHydrogeologieSGH.2002:EinsatzkünstlicherTracerinderHydrogeologiePraxishilfe.Utilisationdestraceursartificielsenhydrogéologie,Guidepratique.BerichtedesBWG,SerieGeologieNr.3–Bern.Availableathttp://www.bafu.admin.ch/hydrologie/01835/02126/index.html?lang=en

Käss,W.1998:TracingtechniqueinGeohydrology.Balkema,Rotterdam.Schnegg,P.-A.,&Doerfliger,N.1997:Aninexpensiveflow-throughfieldfluorometer.ProceedingsoftheSixièmecolloque

d'hydrologieenpayscalcaireetmilieufissuré,laChaux-de-Fonds.Schnegg,P.-A.,2003:AnewfieldfluorometerforMulti-tracertestsandturbiditymeasurementappliedtohydrogeological

problems,Proc.8thInternationalCongressoftheBrazilianGeophysicalSociety,RiodeJaneiro.

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Recent Research on the Remote Retrieval of Soil Moisture from Space with Microwave Radiometry

SchwankMike*,VölkschIngo*,MätzlerChristian**&StähliManfred*

* Swiss Federal Institute for Forest, Snow and Landscape Research, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland, (mike.schwank@wsl.ch)** Institute of Applied Physics, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland.

L-band (1 -2GHz)microwaveradiometry isaremotesensingtechniquetomonitorsoilmoistureover landsurfaces.TheEuropeanSpaceAgency’s(ESA)SoilMoistureandOceanSalinity(SMOS)radiometermissionaimsatprovidingglobalmapsof soilmoisture,with accuracy better than0.04m3m-3 every 3 days,with a spatial resolutionof approximately 40 km.Monitoringthe largescalemoisturedynamicsat theboundarybetweenthedeepbulksoilandtheatmosphereprovidesessentialinformationbothforterrestrialandatmosphericmodellers.Performinggroundbasedradiometercampaignsbe-forethemissionlaunch,duringthecommissioningphaseandduringtheoperativeSMOSmissionisimportantforvalida-tingthesatellitedataandforthefurtherimprovementoftheusedradiativetransfermodels.Thispresentationisanexampleofresearchattheboundarybetweensoilhydrologyandremotesensing.ItstartswithanoverviewoftheSMOSmissionfollowedbyanoutlineofthebasicconceptsbehindremotemoistureretrievalfrompassiveL-bandradiation.ThentheresultsfromaselectionofgroundbasedmicrowavecampaignsperformedwithintheETHdo-mainduringthelast7yearsarepresented.Furthermore,thedesignofanL-bandradiometerisshownwhichwasbuiltforESAtoperformfurthergroundbasedexperimentsduringtheSMOScommissioningandoperativephase.

1.37

Groundwater resources in Switzerland

SinreichMichael*,v.LützenkirchenVolker**,MatousekFederico**&KozelRonald*

*Bundesamt für Umwelt BAFU, Sektion Hydrogeologie, CH-3003 Bern (michael.sinreich@bafu.admin.ch)**Matousek, Baumann & Niggli AG, Geologiebüro, CH-5401 Baden

Groundwaterisaninvisiblebutcrucialcomponentofthewatercycle.Itfeedssurfacestreamsaswellasaquaticecosystems,andisthemaindrinkingwaterresourceinmanycountries.Switzerlandisrichingroundwaterduetofavourableclimatic,hydrologicalandhydrogeologicalconditions,i.e.highrecharge.Morethan80%ofSwissdrinkingwaterrequirementsaremetbygroundwater,andgroundwaterthereforerepresentsasocialandeconomicassetofnationalimportance.Knowledgeabouttheextentoftheresourceisessentialforsustainablegroundwatermanagement.Thisisofparticularinterestgiventhepressureongroundwaterresourcesduetoincreasingwaterdemand,intenseundergroundengineeringactivities,andclimatechange.

TheGroundwaterResourcesMapofSwitzerlandona1:500,000scalepresentstheyieldofnear-surfacegroundwaterresour-cesinaqualitativemanner.Themapprovidesaninventoryofhydrogeologicalunits,subdividedaccordingtohigh,moderateandlowproductivity,whichisdeterminedmainlybyaquiferthicknessandpermeability.However,thismapdoesnotprovi-dequantitativeinformationintermsofthevolumeorthesafeyieldofgroundwaterresources.Whilethegroundwater volumedescribeshowmuchgroundwaterisavailableintheunderground,thesafe yieldisdefinedashowmuchgroundwaterisre-newableandcanthusbeusedinalong-termandsustainablemanner.Bothparametersarecrucialformanaginggroundwa-terresources.Todate,however,theyhavenotbeenassessedinSwitzerlandonanationalbasis.

AstudywasthereforeconductedtoevaluatethevolumeandsafeyieldofSwissgroundwaterresources.Specificapproachesweredevelopedinordertoprovideestimatesforbothparametersforthemainaquifertypesencountered(i.e.porous,fis-suredandkarstifiedrock)andbasedontheGroundwaterResourcesMap.Thisstudywasperformedinco-operationwiththeInstitute of Environmental Engineering and theGeological Institute of the ETHZ (Swiss Federal Institute of TechnologyZurich),andtheSwissInstituteofSpeleologyandKarstologySISKA.

HighlyproductiveporousaquifersalonglargerivervalleysrepresentthemaindrinkingwaterresourcesinSwitzerland.Thegroundwatervolumestored in suchaquiferswasassessedbyconsideringaquifergeometryandporosity.Estimatingsafe

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syields,however,ismoreproblematicastheseaquifersarefedtoalargeextentbytheinfiltrationofriverwater.Inthiscase,amodellingapproachforanextractionscenarioalongariverwithtypicalaquifercharacteristicsprovidedmaximumwith-drawalrates.Forporousaquifersnotconnectedtosurfacestreams,estimatesofsafeyieldwerederivedsolelyfromrechargebyprecipitation.Infissuredaquifers,groundwaterfillstheporesandopenfracturesintheweatheredpartofconsolidatedrock.Estimatesofgroundwatervolumeinfissuredaquifersweremadefromtunnelinflowmeasurementsatselectedsitesincrystallinealpinerocks.Asfissuredandkarstifiedaquifersaredischargednaturallybysprings,dischargedatafromrepresentativespringin-ventorieswereusedtoevaluatethesafeyieldforbothaquifertypes.Finally,ageological-tectonicapproachenabledestimatesof thegroundwatervolume in the saturatedzoneofkarstifiedaquifers,whereas thisvalue is largelydeterminedby thedepthtowhichkarstgroundwaterisregardedassuitableforwatersupply.

1.38

The role of the colloidal pool for transport and fractionation of the rare earth elements in stream water

SteinmannMarc*&PourretOlivier**

*UMR 6249 Chrono-environnement, Université de Franche-Comté, F-25030 Besançon cedex (marc.steinmann@univ-fcomte.fr)**Département Géosciences, Institut Polytechnique LaSalle Beauvais, F-60026 Beauvais cedex (olivier.pourret@lasalle-beauvais.fr)

Therareearthelements(REE)areapowerfultoolforthestudyoftracemetalbehaviorinsurfaceandgroundwatersbecauseoftheirspecificatomicstructureandtheircoherentchemicalpropertiesthroughouttheREEgroup.FractionationofREEdistributionpatternsinwatersampleshaveinthepastbeenusedtomonitorprocessessuchassurfaceandsolutioncomple-xationortoidentifyprecipitationanddissolutionofspecificmineralphases(Gaillardet et al.,2003andcit.therein).RecentstudieshaveshownthattheREEofthe<0.45or<0.22µmfractionofsurfaceandgroundwatersaremainlypresentincollo-idalformratherthantrulydissolved(Gaillardet et al.,2003andcit.therein).Colloidsareorganicorinorganicmicroscopicphasesinasizerangeofabout0.1nmto0.2µm.FortheKalixriverinnorthernSwedenithasbeendemonstratedthatcol-loidsaremoreabundantinsummerandthattheREE-bearingcolloidalfractioniscomposedofFe/Mn-oxyhydroxidesandorganicmatter(Andersson et al.,2006).Theseauthorsfurthermoreshowthatinwintersmall(~3nm)organic-richcolloids,andlarger(~10-12nm)Fe/Mn-oxyhydroxidecolloidscanbedistinguished,whereascombinedFe/Mn-organicmattercolloidsofabout3nminsizeoccurduringspringandsummer.ThedetailedanalysisofthewintercolloidsrevealsthatthelightREE(La-Sm,LREE)arepreferentiallyassociatedwithFe/Mncolloids,whereastheheavyREE(Dy-Lu,HREE)havestrongeraffinityfororganiccolloids(Andersson et al.,2006).ThisdistinctionofthecolloidalREEfractionintoaorganicmatterandaFe/Mn-oxyhydroxidecontrolledpoolisconfirmedbyexperimentalstudies(Pourret et al.,2007a).

Recently,Steinmann&Stille(2008)havereportedfor0.45µmfilteredstreamwatersamplesfromthefrenchMassifCentralacontinuouslygrowingdepletionoftheLREEfromupstreamtodownstreamoveraflowdistanceoflessthan10km(Fig.1).Theauthorsfurthermoreshowedthatthisevolutionislinkedwiththesaturationindex(SI)forFe-oxyhydroxide(goethite,Fig.2):ThestreamwatershaveREEdistributionpatternssimilartothebasalticbedrockupstream,wherethesamplesarestronglyoversaturatedwithrespecttogoethite(SIupto8).Duringdownflow,theSIvalueforgoethitediminishesandtheLREEdepletiondevelops.Steinmann&Stille(2008)haveinterpretedthisevolutionwiththepresenceofFe/Mn-bearingcollo-idsthatgrowduringdownflowandfinallyprecipitateasFe/Mn-oxyhydroxideparticles.ThepreferentialscavengingoftheLREEbytheseprecipitatescouldexplaintheobserveddepletionoftheLREEinthe<0.45µmfraction.

ThescopeofthepresentstudyistoverifythehypothesisofSteinmann&Stille(2008)bydirectanalysisofthecolloidalfrac-tiononnewsamplessampledinSeptember2009inthesamefieldsitebyusingtheultracentifugalproceduredescribedbyPourret et al. (2007a)toseparatethecolloids.ThisnewanalyticalapproachhasbeencompletedwithcomputermodelinginordertoevaluateinmoredetailthecompetitionbetweenorganicandinorganiccolloidsonREEtransportandfractionationinstreamwater.InteractionswithorganiccolloidsweredescribedusingModelVIandthefurtherrefinedREEparametersdescribedbyPourret et al. (2007b).AdsorptionoftheREEontooxyhydroxidecolloidswasmodeledusingasurfacecomplexa-tionmodelintegratedintoPHREEQC.

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Fig.1:EvolutionofLREEdepletionwithdistancemonitoredby

bedrocknormalisedNd/Ybratiosinthe<0.45µmstreamwater

fraction(figurefromSteinmann&Stille,2008)

Fig.2:LinkbetweenNd/Ybratiosthesaturationindex(SI)forgoe-

thite.Notetheregularevolutionwithflowdistance(figurefrom

Steinmann&Stille,2008)

REFERENCESAndersson,K.,Dahlqvist,R.,Turner,D.,Stolpe,B.,Larsson,T.,Ingri,J.&Andersson,P.,2006:Colloidalrareearthelementsin

aborealriver:Changingsourcesanddistributionsduringthespringflood.Geochim.Cosmochim.Acta70,3261-3274.Gaillardet,J.,Viers,J.&Dupré,B.,2003:Traceelementsinriverwaters.In:Drever,J.,Turekian,K.(Eds.),Surfaceandground

water,weathering,andsoils.Elsevier,pp.225-272.Pourret,O.,Dia,A.,Davranche,M.,Gruau,G.,Hénin,O.&Angée,M.,2007a:Organo-colloidalcontrolonmajor-andtrace-

elementpartitioninginshallowgroundwaters:Confrontingultrafiltrationandmodelling.AppliedGeochem.22,1568-1582.

Pourret,O.,Davranche,M.,Gruau,G.&Dia,A., 2007b:Organic complexationof rare earthelements innaturalwaters:Evaluatingmodelcalculationsfromultrafiltrationdata.Geochim.Cosmochim.Acta71,2718-2735.

Steinmann,M.&Stille,P.,2008:Controlsontransportandfractionationoftherareearthelements instreamwaterofamixedbasaltic-graniticcatchmentbasin(MassifCentral,France).Chem.Geol.254,1-18.

1.39

Microbial communities in the steep gradients of the meromictic lake Cadagno

MauroTonolla1,2

1) Microbial ecology group, Microbiology Unit, Plant biologx Dept. Universtity of Geneva c/o Istituto cantonale di microbiologia (ICM), Via Mirasole 22A, CH-6500 Bellinzona & 2) Alpine Biology Center (ABC), Piora, CH-6777 Quinto

LakeCadagnoisacrenogenicmeromicticlakelocatedinthecatchmentareaofadolomiteveinrichingypsuminthePioraValley inthesouthernAlpsofSwitzerland.This lake ischaracterizedbyacompactchemoclineat12mdepthwithhighconcentrationsof sulfate, steepgradientsofoxygen, sulfideand lightanda turbiditymaximumthat correlates to largenumbersofbacteriamostlybelongingtoanerobicphototrophicsulfurbacteriaandsulfatereducingbacteria.Populationanalysesinwatersamplesobtainedfromthechemoclinehavebeenperformedregularlyduringthelast20yearsusingmo-lecularmethodsaswellascultivationtechniques.The16SrDNAbasedclonelibraryobtainedfromsamplesofthemonimo-limnionandtheanoxicsedimentsofthemeromicticLakeCadagnoallowedforthedevelopmentofspecificoligonucleotideprobesandaccurateFISH(fluorescentin situhybridization)distributionanalysisofbacterialpopulations.Phototrophicsul-furbacteria(Lamprocystis, Thiodictyon)formingsyntrophicaggregateswithsulfatereducingbacteria(Desulfocapsa)dominatedthechemoclinewhereasmembersofthegenusDesulfomonilewereprominentinthemonimolimnionandinthefirstcenti-

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smetersofthesediments.IndeepersedimentlayersmethanogenicarchaeaandSRBweredetectedbyFISH.Moreover,inthechemocline,spatio-temporalanalysisofbacterialpopulationsover2decadesrevealedaninitialdominanceof Chromatiaceae (C. okenii, Lamprocystis, Thiodictyon), after 2001, a clonal population of Chlorobium clathratiforme becamedominant.Thismajorchangeincommunitystructureinthechemoclinewasprobablyduetoextremeclimaticeventsinautumnoftheyears1999and2000causingdeepmixingofthewaterbodywhichwereaccompaniedbychangesinprofilesof turbidity andphotosynthetically available radiation, aswell as for sulfide concentrations and light intensity.Overall,thesefindingssuggestthatthetemporarydisruptionofthechemoclinemayhavealteredenvironmentalnichesandpopula-tionsinsubsequentyears.

REFERENCES:Tonollaetal.(1998)DocumentaIst.ital.Idrobiol.63:31-44.Bensadounetal.(1998)Doc.Ist.ital.Idrobiol.63:45-51.Tonollaetal.(1999)Appl.Environ.Microbiol.65:1325-1330Tonollaetal.(2000)Appl.Environ.Microbiol.66:820-824.Tonollaetal.(2003)FEMSMicrobiol.Ecol.43:89-98.Peduzzietal.(2003)FEMSMicrobiol.Ecol.45:29-37.Peduzzietal.(2003)Aquat.Microb.Ecol.30:295-302.Tonollaetal.(2004)J.Limnol.63(2):157-166.TonollaM.,etal..(2005)FEMSMicrobiologyEcology53:235–244.TonollaM.etal.(2005)Appl.Environ.Microbiol.71:3544-3550.DecristophorisP.M.A.etal.(2009)J.Limnol.,68(1):16-24.GregersenL.H.etal.(2009Jul1.[Epubaheadofprint])FEMSMicrobiologyEcology

1.40

Dissolved inorganic carbon and its stable isotope composition as a tracer of geo-, bio-, and anthropogenic sources of carbon

VennemannTorsten*,FontanaDaniela*,PaychereSophie*,AmbadiangPierre*,PiffarerioRaffaella*,andFavreLaurie*.

*Institut de Minéralogie et Géochimie, Université de Lausanne, CH-1015 Lausanne (Torsten.Vennemann@unil.ch)

Theconcentrationandcarbonisotopecompositionofdissolvedinorganiccarbon(DIC),inadditiontotheoxygenandhydro-genisotopecompositionsofwateraswellasthemajordissolvedcationsandanionshavebeenanalyzedseasonallyforseve-ralrivers,lakes,damsusedassourcesforhydroelectricenergy,andeffluentsfromanumberofwastewatertreatmentplants(WWT)inWesternSwitzerland.TheaimistoevaluatetheDICanditsisotopiccompositionasatracerforthegeologic,bio-logicandanthropogeniccontributionsofcarbontotheriversandlakes.

TheupperreachesoftheRhoneandtheSarinetypicallyhaveAlpinecatchmentscharacterizedbythinornosoilcoverswithonlysparsevegetation.Glacialmeltwatersandsurfacerunoffmakeupthebulkofthewatersourcesintheirupperreaches.Furtherdownstreamothertributaries,themselvesoftenbeingmeltwaterfedbutmanyalsobeingexploitedforhydroelec-tricpowerandthuswithanumberofdamsalongtheircourse,jointheserivers.Inaddition,thevegetationandsoilcoverincreasesdownstreaminparallelwiththeagriculturalexploitation,populationdensity,andthenumberofWWTplantsthatgenerallypasstheirtreatedwastewatersdirectlyintotherivers.Incontrast,riversdrainingtheJuramountainsdonothaveaglacialmeltwatersource,noraretheremajorhydroelectricsystemscoupledtotheriversystemsinvestigated.

Thedifferenceingeologyofthecatchmentaswellasthesoilcoverthicknessandhencebiologicactivityinthesoilarere-flectedbytheCisotopecompositionoftheDIC.δ13Cvaluesareashighas–2.5‰intheuppersourcereachesoftheRhoneandtheSarine,reflectingpredominantuptakeofcarbonfromatmosphericCO

2.Furtherdownstream,δ13Cvaluesdecrease

towards–5to–11.5‰,compatiblewithahigherinputofsoil-,plant-derivedCO2.Theδ13CvaluesofDICarehigher(–5to–

8.5‰)ifcarbonaterelativetosilicaterocksdominatethecatchment,unlesstheagriculturalactivityisintense.Thelatteristhecasefortheriversdrainingthelargelycarbonate-dominatedJura(forexampletheVenoge),whichhaveδ13Cvaluesofbetween–11to–13‰.Theδ13Cvaluesarealsohigherforalllakesanddamsalongtherivers,indicatinganadditionalex-changewithatmosphericCO

2forwatermassesexposedtotheatmospherefor longerperiods.Forsmaller lakes,theδ13C

valuescorrespondtothoseoftheriverine inputsthough.For larger lakestheδ13CvaluesoftheDICmayalsobeusedastracersofthemixingprocessesbetweenriverineinputandthelake(Fig.1).

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Theδ13Cvaluesintheriversaregenerallylowerinwinterandspringcomparedtosummerandfall,indicatingahigherbio-logicalactivitywithinthewatercolumnduringthewarmerperiods.Thedifferencesaremostnotableindamsandlakes,whereverticalprofilesarealsowell-establishedwithintheupper5to10mofthewatercolumnasaresultofincreasingphotosynthesisduringthewarmerperiods(Fig.1).

ContributionsoforganiccarbonfromWWTplantsareclearlymarkedby0.5to3‰lowerδ13CvaluesforDICdirectlydown-streamoftheeffluents,withthetreatedwastewatershavingvaluesthatmaybeaslowas–27‰.SuchsourcesmayalsoclearlybeexpressedbydifferencesinH-andO-isotopecompositionsofthewatersrelativetotheriverorlakewaters,aswellastheirsodium,potassiumandnitratecontents,aswellastheisotopiccompositionofthelatter.

Figure1:δ13CvaluesofDICinadepthprofileinthedeepestpartofLakeGeneva(approximatelyinthecenterofthelake).Notethehigh

valuesatthesurfaceduringthesummer(July2005profile)comparedtothewinter(March2005profile)typicallyindicatingthebiopro-

ductivityinthephoticzoneduringsummer.Highervaluesatdepthsof50to100mrepresentmixturesoftheRhonewaterrichin13Cde-

scendingtothesedepthswithinthelake,threemonthsafteracompleteoverturnofthelakeattheendofFebruary.

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s1.41

High-resolution temperature measurements at the river – groundwater interface: Quantification of seepage rates using fiber-optic Distributed Temperature Sensing

T.Vogt*,P.Schneider*,M.Schirmer*,O.A.Cirpka**

* Eawag - Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf (tobias.vogt@eawag.ch)** University of Tübingen, Center for Applied Geoscience, Sigwartstr. 10, D-72076 Tübingen

Inrecentyears,thetransitionzonebetweensurfacewaterbodiesandgroundwater,knownasthehyporheiczone,hasbeenidentifiedascrucialfortheecologicalstatusoftheopen-waterbodyandthequalityofgroundwater.Thehyporheicexchangeprocessesvarybothintimeandspace.Fortheassessmentofwaterqualityofbothwaterbodiesreliablemodelsandmeasure-mentsoftheexchangeratesandtheirvariabilityareneeded.

Awiderangeofmethodsandmaterialsexisttoestimatewaterfluxesbetweensurfacewaterandgroundwater.Duetoad-vancesinsensortechniqueanddataloggers,workonheatasatracerinhydrologicalsystemshasincreasedrecently,espe-ciallywithfocusonsurfacewater–groundwaterinteraction.AnewpromisingmethodisDistributedTemperatureSensing(DTS).DTSisbasedonthetemperaturedependenceofRamanscattering.Lightfromalaserpulseisscatteredalonganopti-calfibreofuptoseveralkmlength,whichisthesensoroftheDTSsystem.Bysamplingtheback-scatteredlightwithhightemporalresolution,thetemperaturealongthefibrecanbemeasuredwithhighaccuracy(0.1K)andhighspatialresolution(1m).WeusedDTSatatestsideatRiverThurinNorth-EastSwitzerland(TG).Here,theriverislosing.

Forestimationofseepagerateswemeasuredhighlyresolvedverticaltemperatureprofilesintheriverbed.Tothisend,wewrappedanopticalfibrearoundapiezometertubeandmeasuredthetemperaturedistributionalongthefibre.Duetothewrapping,weobtainedaverticalresolutionofapproximately5mm.WeanalyzedthetemperaturetimeseriesbymeansofDynamicHarmonicRegressionaspresentedbyKeeryetal.(2007).Fromthetraveltimeandattenuationofthediurnalsignal,weestimatedtheapparentvelocityanddiffusivityoftemperaturepropagation,whichthencanbeusedtoquantifyinfiltra-tionrates.Aparticularstrengthofthenewmeasurementtechniquelies inthehighspatialandtemporalresolution,en-ablingustodetectnon-uniformityandtemporalchangesinverticalwaterfluxes.

REFERENCESJ.Keery,A.Binley,N.CrookandJ.W.N.Smith(2007)Temporalandspatialvariabilityofgroundwater–surfacewaterfluxes:

Developmentandapplicationofananalyticalmethodusingtemperaturetimeseries,JournalofHydrology,336,1-16.

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Natural springs – the living passage between groundwater and surface water

VonFumettiStefanie*,GusichValeria*&NagelPeter*

*Institut für Biogeographie (NLU), Universität Basel, St. Johanns-Vorstadt 10, CH-4056 Basel (stefanie.vonfumetti@unibas.ch)

Naturalspringsareuniqueecosystemsthatprovidespecificabioticconditions,andtheyarestepping-stonesbetweenground-waterandsurfacewater.Theyappearinthelandscapeinvariousformsandareespeciallyobviousinalpineregions.Springsarehabitatsformanyfreshwaterorganisms,whichpartlyshowastrongadaptationtothespecificconditionsinsprings.AsanalpinecountrySwitzerlandisrichofsprings,butnotmanyarestillinanaturaloratleastnearnaturalcondition.Despitetheirimportanceasuniquehabitatsanddespitetheirendangeredsituationtheywerenotwellstudieduntilafewyearsago.At the Institute of Biogeography from the University of Basel we investigate natural springs in the northern part ofSwitzerlandandadjacentregions.Thedistributionofthespringfaunaandtheinfluenceofabioticparameters,especiallydischarge,arethemaintopicsofourresearch.Afirstapproachtoafaunisticspringtypologyshowsdifferencesbetweenspringsbasedonthedominantfeedinghabitsofthemacrozoobenthicspecies.Theyarerelatedtoabioticparameterslikesubstratecomposition.Ourgoalisaspringtypologyforthewholecountrybasedonfaunisticdata.Andalsothecolonisationofspringsisanimportantpartofourresearch.Inaone-yearfieldexperimentinartificialspringsweinvestigatedthecolo-nisationrateandthepreferencesofdifferentsubstratesbymacrozoobenthicorganisms.Mesoscaleanalysesshowthatthecolonisationoccursrapidlyfromtheadjacentheadwaterandthattheorganismspreferdifferentsubstratetypesfortheirsettlement.

1.43

Porewater as an archive of the palaeo-hydrogeology during the Holocene and Pleistocene

WaberH.Niklaus

Institute of Geological Sciences, Rock–Water Interaction Group, University of Bern, Baltzerstrasse 1-3, CH-3012 Bern (waber@geo.unibe.ch)

Fracturedrockscomprisetwodifferenthydraulicregimes:Thefirstregimeconstitutesthewater-conductingzonesrelatedtoregionaland/orlocalfracturenetworkswheregroundwaterflowtakesplace.Itischaracterisedbyahydraulictransmissi-vityofmostlyabove10-9m2/sandsolutetransporttakesplacebyadvection.Thesecondregimeconstitutesthelowpermeablerockmatrixwiththeporewaterresidinginitsconnectedporespace.Here,thehydraulictransmissivityislowtoverylow(<<10-10m2/s)andsolutetransportisincreasinglydominatedbydiffusion.Themassofporewaterpresentintherockmatrixis,however,largerthaninthefracturenetworkevenincrystallinerockswithaconnectedporosityoflessthan1Vol.%.

Porewaterintherockmatrixandgroundwaterinthefracturenetworkalwaystendtoreachchemicalandisotopicequilibri-um.Ifsolutetransportintherockmatrixcanbeshowntooccurbydiffusion,thenachemicalandisotopicsignatureesta-blishedintheporewateratacertaintimemightbepreservedovergeologictimeperiods.Thus,porewatermayactasanar-chiveofthepastfracturegroundwatercomposition(s)andthereforeofthepalaeo-hydrogeologicalhistoryofasite.Thede-greeofthepreservationofsuchsignaturesdependson:1)thedistanceoftheporewatersamplefromthenearestwater-con-ductingfractureinthreedimensions,2)thesolutetransportpropertiesoftherock(i.e.diffusioncoefficient,porosity),and3)theperiodofconstantboundaryconditions(i.e.constantfracturegroundwatercomposition).ThefrequentclimaticandhydrogeologicchangesduringtheHoloceneandPleistoceneandrelatedcompositionalchangesinthefracturegroundwaterresultedinsuperimposedsignaturesintheporewater.Thesecanbeunravelledtoalargedegreebytheinvestigationofdif-ferent,largelyindependentnaturaltracersintheporewater.

PorewateringraniticandmonzodioriticrocksfromLaxemar-Oskarshamn,centralSweden,areofdifferentchemicalandisotopiccompositioninbedrockcharacterisedbyhightransmissivityandahighfrequencyofwater-conductingfracturesatshallowtointermediatedepth(0-400mb.s.l.),andbedrockcharacterisedbylowtransmissivityandalowfrequencyofwater-conductingfracturesatgreaterdepth(400-1000mb.s.l.).Inthemoretransmissive,shallowerinterval,porewaterisofage-neralNa-HCO

3chemicaltypewithaCl-concentrationoflessthan1g/kgH

2O.Theoxygenandhydrogenisotopecomposition

indicatesaformationfrommeteoricinfiltrationunderdifferentclimaticconditions.Combinedwiththedistancebetweenporewatersampleandnearestwater-conductingfractureintheboreholeandthequantitativemodellingofthenaturaltra-cerprofiles(Cl-,δ18O,δ2H)sampledathighresolutioninoneoftheboreholes,theporewatersignaturesinthefirstfewmetresfromafracturemaybeexplainedintermsofexchangewithHolocenefracturegroundwaterofpresent-daytype,ofHolocene

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sthermalmaximumtype(atabout7-4kaBP)andofglacial(lateWeichselian)orglacio-lacustrine(BalticIceLake,15-11.5kaBP;AncylusLake,10.8-9.5kaBP)type.Exchangewithfracturegroundwatercomposedofpresent-daybrackishwateroftheBalticSeaislimitedandabsentfortheearlierBalticSeastages(Yoldia,11.5-10.8kaBP;salineLittorina,8.5-7kaBP).Fartherawayfromwater-conductingfractures,Na-HCO

3typeporewatersignatureswithlowCl-concentrationsindicateanevolution

fromPleistocenefracturegroundwaterofwarmclimateorigin(possiblyEemianInterglacial)andcoldclimateperiods(earlyWeichselianorolder).Coldclimateinfluencefromthelastglaciationwithδ18Ovaluesaround-14‰VSMOWoccursbetweenabout135-350mdepthanddowntoabout500mdepthdependingonborehole.

AtintermediatedepthlevelsbelowtheNa-HCO3typeporewaterachangetohighermineralisedporewaterofageneralNa-

Ca-SO4andCa-Na-SO

4chemicaltypeoccurs.Dependingonboreholelocationthisporewatertypeoccursfromabout430m

and620mdepthoverarestrictedintervalofabout120m.Thechangecoincideswithamarkeddecreaseintransmissivity,inthefrequencyofwater-conductingfeaturesandthetransitionzonefromÄvrögranite toquartzmonzodiorite.HighlyvariableCl-concentrations(2.5to7.6g/kgH

2O)andwaterisotopecompositions(δ18Oabout-2‰to-13‰VSMOW)areassocia-

tedwithhighconcentrationsofCa2+andSO42-uptogypsumsaturation.Chemicalandisotopiccompositionoftheseporewa-

tertypescannotbeexplainedbyinteractionwithaknowntypeoffracturegroundwaterandmoreadvancedrock-waterin-teraction.Theyappeartohaveformedfrominteractionwithcryogenicbrinesthatformedduringpermafrostconditionsandwhichmigrateddownwardsinthefracturesbybuoyancyeffects.Thelargedistancetothenearestwater-conductingfractureofthisporewatertypesuggeststhatthesesignatureshavebeenestablishedbeforetheLastGlacialMaximum.

AtgreaterdepththereoccuragainmorediluteporewatersofNa-HCO3typeandNa-Ca-Cl-(HCO

3)type.Here,Cl-contentsvary

betweenabout0.5to3g/kgH2Oandassociatedδ18Ovaluesofbetweenabout-8‰to-11‰VSMOW.Porewatersbelow820m

arethenofaNa-Ca-CltypewithCl-concentrationsofmorethan8g/kgH2O,butlowSO

42-concentrationsandanoxygeniso-

topecompositiongenerallyenrichedin18Ocomparedtothemoreshallowporewaters.Attheselow-transmissivitydepths,theporewatersdisplaycomplex,superimposedsignaturesthatcannotberesolvedbasedonthepresentdata.Inthedeepestsamples,however,acomponentofadeepsalinebrineseemstobepresentsimilarasobservedinfracturesatevengreaterdepth.

Thedataindicatethatthepalaeo-hydrogeologicalevolutionofasiteindeedcanbere-constructedbasedonporewaterdata.Inaddition,signaturesnolongerpresentinthefracturegroundwaterscanbeidentified.Inthecaseofcryogenicbrinesthatformedduringpermafrostconditions,thisisofspecialimportancewithintheframeworkofthelong-termsafetyassessmentofadeepgeologicrepositoryforradioactivewaste.

1.44

In-situ Remediation of Polluted Groundwater: A Transdisciplinary Approach

ChristophWanner*,FranzSchenker**&UrsEggenberger*

*Institut für Geologie, Baltzerstr. 1+3, CH-3012 Bern (christoph.wanner@geo.unibe.ch)**Geologische Beratungen SCHENKER KORNER + PARTNER GmbH, Büttenenhalde 42, CH-6006 Luzern (franz.schenker@fsgeolog.ch)

Carelesshandlingofenvironmentallyhazardoussubstancesandwasteshasleftitsmarkinthegeologicalunderground.Ifsubstanceslikepersistentorganiccompoundsorheavymetalsfromcontaminatedsitesmigrateintothegroundwater,animmediateandsustainablesuppressionofthesourceisrequired.However,inmostcasesthegroundwaterinitsdownstreamflowwillstaycontaminatedoveralongtime.Ondutyofthesocietyandtheenvironmenttoprovideforsafewater,there-mediationofpollutedgroundwaterisbothanessentialandambitioustask.

Consultantgeologistsincooperationwithchemicallaboratoriesgenerallyarekeennowinassessingthetype,amountanddistributionofcontaminants ingroundwater.Butafteronedecadeof thecommitmentby lawtoremediate the“sinsofyesterday”,thescientificandtechnicalknowledgeonapprovedprocedurestocleanspoiledgroundwaterisstillpoor.Ontheonehandresearchinstitutesmostlyexperienceatlaboratoryscaleonly.Attheotherhand,thepartyresponsibleforacon-taminatedgroundwaterplumeisinterestedinfastsolutions,andnotinmakingexpensiveattemptswithoutaguarantyofalonglastingachievement.Researchersfromtheuniversityandprofessionalsfromconsultingcompaniescancomplementoneanotherincreatingnewtechnologies.Research,developmentandimplementationofnewtechnologiescanprofitfrom“theNineLawsofGodgover-ningtheincubationofsomethingfromnothing”(Kelly,1995).Takingasanexampletheprojecttoreducethechargeofhe-

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es xavalentchromiumwithpermeablereactivewalls(PRB),thewayofasuccessfulcooperationusingatransdisciplinaryap-

proach(Hermanns-Stengele&Schenker,2000)willbedemonstrated.

IndesigningaPRBasapassiveremediationmethodthecrucialaspectsarewhat to takeas thereactivematerialandofcoursehowwellthecontaminantsaretreatedaftertheinstallationofsuchaPRB.BatchandcolumnexperimentsperformedinordertochosethebestavailableironshavingsforthePRBThunshowedthatshavingswithacarboncontentofapproximately4%haveverygoodpropertiesconcerningthereductionofhexavalentchro-mium.Interestinglylargedifferencesinthereactionratesamongvarioustypesofironshavingswereobserved.Lookingatthevariousshavingsunderthescanningelectronmicroscopewecameupwiththeconclusionthatreactionratesarehighlycorrelatedwiththenatureofthecarboninclusionswithintheironmatrixoftheshavings.Inordertoestimatethesuccessoffuturebarrieroperationsgeochemicalmodelsarecheapandpowerfultools(Steefel,2005).UsingthedataofthelabexperimentsthegeochemicalreactivetransportmodelandreactionnetworkofMayeretal.(2001)wascalibratedusingthemodelingsoftwareCrunchflow(Steefel,2005).Thecalibratedmodelwasusedtosimulatethehy-drodynamicsandhydrogeochemistrywithinthedoublepile-arrayofthebarrierin2D.Examplesofmodeloutcomesareil-lustratedinfigure1.

ThemodellingworkclearlypointsoutthatthelimitingfactorsintheperformanceofthePRBarethegroundwaterflowvelocity,thepermeabilityofthepilesandthegroundwaterchemistry.

Figure1.Illustrationsof2DmodelcalculationsofthePRBsiteThun:Modelsetupintermsofporosityintheupperleftpicture,aqueous

Fe2+concentrations(mol/l)upperright,greenrustprecipitationvolumes(vol%)bottomleftandaqueousCrVIconcentrations(mol/l)bottom

right.

REFERENCESHermanns-Stengele,R.&Schenker,F.2000:Groundwater-Remediationwithpermeablereactivewalls–ATransdisciplinary

Approachtothesustainableuseofthemostimportantnaturalressource.In:Transdisciplinarity:JointProblem-SolvingamongScience,TechnologyandSociety.ProceedingsoftheInternationalTransdisciplinarity2000Conference,590-593.

Kelly, K. (1995): Out of Control: TheNew Biology ofMachines, Social Systems and the EconomicWorld. Reading/Massachusetts:Addison-Wesley.

Mayer,U. Blowes,D.& FrindE. 2001: Reactive transportmodeling of an in situ reactive barrier for the treatment ofhexavalentchromium.WaterResourcesResearch38,3091-3103.

SteefelC.2001:Softwareformodelingmulticomponent,multidimensionalreactivetransport.LawrenceLivermoreNationalLaboratory,Livermore,Ca.UCRL-MA-143182.

Steefel,C.DePaolo,D.&LichtnerP.2005:Reactivetransportmodeling:AnessentialtoolandanewresearchapproachfortheEarthsciences.EarthandPlanetaryScienceLetters240,539–558.

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s1.45

On the physical hydrology of hydrothermal systems at mid-ocean ridges

PhilippWeis*,ThomasDriesner*,DimCoumou**,&ChristophA.Heinrich*

* Institute of Isotope Geochemistry and Mineral Resources, ETH Zurich, Switzerland (philipp.weis@erdw.ethz.ch)** Potsdam Institute for Climate Impact Research, Germany

Fluid evolution andmigration inmagmatic hydrothermal systems strongly depend on the physical properties ofwater.Withinthepressureandtemperaturerangegivenbyaspecificgeologicsetting,fluidpropertieslikedensityandviscosityvarynon-linearlybyordersofmagnitude(DriesnerandHeinrich,2007).

Magmatism atmid-ocean-ridges is predominantly basaltic and acts as a heat source for hydrothermal convection cells.Seawaterpercolatesthroughtheoceanfloorintothesubsurface,isheatednearthemagmachamber,travelsupward,andventsattheoceanfloor,eventuallyformingblacksmokerfields.Numericalsimulationsin3Dwithpurewaterandahomogeneouspermeabilityhaveshownthatthesystemnaturallyformsregularly-spacedpipe-likeupflowzoneswhichiswell-supportedbymeasurementsandobservations(Coumouetal.,2008).Thesesimulationsfurtherrevealedthatmostofthedownflowoccursintheimmediatevicinityoftheupflowzonewherefluidsareheatedtoabout200°C.Comparedtothecolderfluidsatlargerdistancefromtheaxis,theirviscosityislowerbyoneorderofmagnitudewhiletheyarestillrelativelydensehencemaximizingdownwardfluidtransport.Incombinationwiththe~400°Cfluidsoftheupflowzone,thisleadstoamassandenergyfluxoptimization(seealsoDriesneretal.,thisvolume).

Introducinggeologicalstructurestothemodelgeometryaddsfurthercomplexitytothesystembutpreservesthefirstorderprincipledescribedabove.Figure1showsconvectionatamid-oceanridgesystemwithadeepergabbroicpartoverlainbyabasalticlayerofhigherpermeability.Thesimulationsshowthatasecondaryconvectioncellestablisheswithinthehighlypermeablebasaltlayerresultinginamoreefficientcoolingoftheupperpartoftheupflowzone.Normalfaultswithintheoceaniccrustnear theridgeaxisareoftenreferred toasconduits forenhancedup-ordownflow (Fisher,1998).Firstnu-mericalsimulationsintroducingnormalfaultsasheterogeneitieswithinthepermeabilitystructureofthemodelgeometryhavebeenconducted.Downflowvelocities similar to theonesdescribedaboveonlydeveloped in relativelywidenormalfaults(50m)thathaveahighpermeabilitycontrasttothesurroundingrock(uptotwoordersofmagnitude)andarelocatedveryclosetotheridgeaxis.

Figure1.Convectionatmid-ocean-ridgesself-organizesintohotpipe-likeupflowzones(a).Downflowconcentratesintheimmediatevici-

nityoftheupflowzoneasshownbytheporevelocitiesoftheselectedstreamlines(b).Themodelgeometrydescribesa1kmdeeppieceof

oceaniccrust(3x4km2).Constantfluidpressureatthetopboundaryrepresentsawaterdepthof2.5kmandabell-shapedheatfluxatthe

bottomboundaryofatotalof350MW/kmrepresentsanaxialmagmachamberatdepth.Thepermeabilitystructureconsistsofalower

gabbroiclayer(k=3x10-14m2)overlainbya200mthickbasalticlayer(k=10-12m2).Figure1bisa1km3excerptofFigure1a.

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Coumou,D.,T.Driesner,P.Weis,andC.A.Heinrich(2009),Phase-separation,BrineFormationandSalinityVariationatBlackSmokerHydrothermalSystems,J.Geophys.Res.,114,B03212.

Coumou,D.,T.DriesnerandC.A.Heinrich (2008),Thestructureanddynamicsofmid-oceanridgehydrothermalsystems,Science,321,1825-1828.

Driesner,T.,andC.A.Heinrich(2007),ThesystemH2O-NaCl.PartI:Correlationformulaeforphaserelationsintemperature-pressure-compositionspacefrom0to1000degreesC,0to5000bar,and0to1X-NaCl,GeochimicaEtCosmochimicaActa,71,4880-4901.

Fisher,A.(1998),Permeabiltywithinbasalticoceaniccrust,Rev.Geophys.36,143-182.

1.46

One lake, two countries and a lot of methane - the concept for a viable extraction of an unusual resource

AlfredWüest*,**,LukasJarc*,**,NatachaPasche*,**&MartinSchmid*

*Eawag, Swiss Federal Institute of Aquatic Science and Technology, Surface Waters - Research and Management, CH-6047 Kastanienbaum, Switzerland (alfred.wueest@eawag.ch)** Swiss Federal Institute of Technology, Institute of Biogeochemistry and Pollutant Dynamics, CH-8092 Zürich, Switzerland

The485mdeepLakeKivu(Rwanda,DRCongo)isamongthemostfascinatinglakesonearth.Notonlydoesithostaspecta-culartemperature-salinitystaircaseofmorethan300interface-layers,italsocontains~60km3ofmethaneand~300km3ofcarbondioxide and is permanently density-stratified by salty, carbondioxide-richwater released by sub-aquatic springs.Thosespringsandtheirchemicalcompositionaffectthelakestratification.Especially,thelake-internalnutrientupwelling,stronglydependingonthespringdischarges,iscrucialforalgaegrowthandthesubsequentmethaneproductioninthedeepwaters.Overthecenturies,methanehasaccumulatedtoanamount,whichcanbeeconomicallyexploited,butwhichalsoposesarisk(limniceruptionlikeinLakeNyos)totheriparian~2millionpeople.Toavoidbuilding-upofsuchariskofgaseruption,thetwogovernmentshavedecidedtoexploitthemethane,worthmorethan$20billions.

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0.00 0.02 0.04 0.06 0.08 0.10

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0 1 2 3 4 5 6Salinity (g L-1)

Depth (m)

temperature salinity CO

2 concentration

CH4 concentration

Gas concentrations (mol L-1)

Figure1.Verticalprofilesoftemperature,salinity,CH4andCO

2,asobservedinFebruary2004(Schmidetal.2005).Allmajorwaterconsti-

tuentsareincreasingwithdepthduetothedischargeofdeepsub-aquaticsprings.

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sThetalkwillfocusonfindingaextractionconcept,which(i)lowerstheriskofagaseruptionfromthelake,(ii)isenviron-mental-friendlyandconservesthelake’secologicalintegrityand(iii)maximizestheeconomicbenefitatthesametime.

REFERENCESLorkeA.,TietzeK.,HalbwachsM.,WüestA.(2004)ResponseofLakeKivustratificationtolavainflowandclimatewarming.

LimnologyandOceanography49(3),778-783.MuvundjaF.A.,PascheN.,BugenyiF.W.B.,IsumbishoMwapu,MüllerB.,NamugizeJ-N.,RintaP.,SchmidM.,StierliR.,Wüest

A. (2009) Balancingnutrient inputs to LakeKivu. Journal ofGreat LakesResearch 35 (2009) 406–418, doi:10.1016/j.jglr.2009.06.002

PascheN.,DinkelC.,Müller B., SchmidM.,WüestA.,Wehrli B. (2009) Physical andbiogeochemical limits to internalnutrientloadingofmeromicticLakeKivu.LimnologyandOceanography,54(6),2009,1863–1873.

SchmidM.,HalbwachsM.,WehrliB.,WüestA. (2005)WeakmixinginLakeKivu:Newinsights indicate increasingriskofuncontrolledgaseruption.GeochemistryGeophysicsGeosystems6,Q07009,doi:10.1029/2004GC000892

SchmidM.,TietzeK.,HalbwachsM.,LorkeA.,McGinnisD.F.,WüestA.(2003)HowhazardousisthegasaccumulationinLakeKivu?ArgumentsforariskassessmentinlightoftheNyiragongoVolcanoEruptionof2002.ActaVulcanologica15(1-2),115-122.

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s 2. Structural Geology, Tectonics and GeodynamicsNeil Mancktelow, Guido Schreurs, Paul Tackley

Swiss Tectonics Studies Group of the Swiss Geological Society

2.1 BagheriS.,ArefNejadM.,YabalouiM.:TectonichistoryoftheLutBlockinNehbandanarea,EasternIran

2.2 BagheriS.,BuchsD.,SalariT.,NabaviM.:NeogenetectonicsoftheAnarakareainCentralIran

2.3 BagheriS.,StampfliG.M.,MoixP.,BakhshiM.R.:Khurplatform:TectonicevolutionofapartoftheNeo-Tethyanback-arcbasininCentralIran

2.4 BejaouiJ.,SellamiA.:TectoniccontrolofPb-Zn-Ba-(Sr)depositatOuedJebs-KefLasfar,northernTunisia

2.5 BuckinghamT.,HerweghM.,PfiffnerO.A.: PolymineralicMylonitesGeneratedbyChemo-MechanicalMixing:TheGlarusThrustasanExample

2.6 CammaranoF.,PaulTackleyP.,NakagawaT.,StixrudeL.,Lithgow-Bertelloni,C.,XuW.,RomanowiczB.:GeologyandgeochronologyoftheIlobatholithofsoutherncoastalPeru

2.7 CardelloG.L.,BernoulliD.,DoglioniC.:TectonicsofthewesternGranSassod’Italia(CentralApennines)

2.8 CardelloG.L.,MancktelowN.:NeogenetranstensionaltectonicevolutionofthecentralHelveticnappes:preliminaryresults

2.9 Castelltort S., Nagel S., Mouthereau F., Tien-shun L.A.,Wetzel A., Kaus B.J.P,Willett S.D., Shao-Ping C.,Wei-Yi C.:Sedimentology of Early Pliocene Sandstones In the South-Western Taiwan Foreland: Implications for BasinPhysiographyattheOnsetofCollision.

2.10 CrameriF.,KausB.J.P.,TackleyP.J.:One-sidedsubductioninself-consistentmodelsofglobalmantleconvection:theimportanceofafreesurfaceandaweakcrustallayer

2.11 CrameriF.,KausB.J.P.,TackleyP.J.:Parametersthatcontroltheformationoflithospheric-scaleshearzones

2.12 DietrichV.J.,GartzosE.:TwinmeteoriteimpactcratersinThessaly(CentralGreece)ofHoloceneage

2.13 DuretzT.,GeryaT.V.:Rheologicalmechanisms,topographicresponse,andgeodynamicregimesassociatedwithslabbreakoff

2.14 EgliD.,MancktelowN.:NewstructuralfielddatafromSEoftheMontBlancmassifandpreliminaryconstraintsonmodelsofexhumation

2.15 FrehnerM.,SchmalholzS.M.:ReflectionandscatteringofStoneleyguidedwavesatthetipsoffluid-filledfractures

2.16 GasserD.,BruandE.,StüweK.:Exhumationofametamorphiccomplexinastrike-slipsetting:observationsfromtheChugachMetamorphicComplex(CMC),southernAlaska

2.17 GasserD.,MancktelowN.:TheRezlifaultzone:Fieldobservationsfromamajoroblique-slipfaultintheRawildepres-sion,WesternSwitzerland

2.18 GolabekG.,GeryaT.,KausB.,ZietheR.,MollG.-P.,TackleyP.J.:Influenceofrheologyandgiantimpactorsontheter-restrialcoreformation

2.19 GolabekG.,KellerT.,GeryaT.,Connolly J.: Towards self-consistentmodellingof theMartiandichotomy:Coupledmodelsofsimultaneouscoreandcrustformation

2.20 GuerraI.,StockliD.,CorfuF.,NegroF.,MancktelowN.,VennemannT.:IntegratedU/Pb,(U-Th)/HeandoxygenstableisotopestudyonzirconofanormalfaultzoneofthewesternAlps,Switzerland

2.21 HaghipourN.,BurgJ.-P.,KoberF.,ZeilingerG.:Quaternaryfluvialpatternsonthein-landMakranaccretionarywedge(SEIRAN)

2.22 HärtelM.,HerweghM.:StrainlocalizationinquartzmylonitesoftheSimplonFault,CentralAlps

2.23 HunzikerD.,BurgJ.-P.,BouilholP.,JafarO.:Petrographyandgeochemistryofuppermantleandlowercrustofsupra-subduction(?)ophiolitesintheMakran,SEIran

2.24 IbeleT.,MatzenauerE.,MosarJ.:BrittledeformationbandsinthesandstonesoftheWesternSwissMolasseBasin

2.25 Kais,A.,OuldBaggaM.A.,AbdeljaouadS.,ZargouniF.,MercierE.: LateralFold Identification inNorthernTunisiaThrustBeltFront

2.26 KausB.J.P.,BeckerT.W.:Insightsinthedynamicsoffreesubductionfromsemi-analyticalandnumericalmodels.

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2.27 KellerT.,KausB.J.P.:Numericalmodelsoffluidmigrationinatectonicallyactivecontinentalcrust

2.28 KilianR.,HeilbronnerR.,StünitzH.,HerweghM.:Flowmechanismsingraniticultramylonites

2.29 LechmannS.M.,SchmalholzS.M.,KausB.J.P.,HetényiG.:Comparingthin-sheetmodelswiththree-dimensionalnume-ricalmodelsfortheIndia-Asiacollision

2.30 Linckens J.,HerweghM.,MüntenerO.: Strain localizationand the importanceof secondphases inpolymineralicmantleshearzones

2.31 LuG.,KausB.J.P.,ZhaoL.:Numericalmodellingofcratondestruction

2.32 MadonnaC.,TisatoN.,BoutareaudS.,ArtmanB.,BurliniL.: Newexperimentalapproachtomeasureseismicwaveattenuationofrocksatlowfrequency

2.33 MalatestaL.,MishinY.,Gerya,T.:TheSingularitiesofDoubleSubductionSystems

2.34 MayD.A.,KnepleyM.G.,GurnisM.:CitcomSX:RobustpreconditioninginCitcomSviaPETSc

2.35 Mejri L., RegardV., Carretier S., Brusset S., DlalaM.: Seismotectonic study inNorthern Tunisia (exemple:UtiqueStructure)

2.36 MettierR.:Numericallymodelingcurrentverticalsurfacemotionintheswissalpsfromthebottomup-Doesthegeometryoftheorogendictatehowitmoves?

2.37 MisraS.,AlmqvistB.S.G.,BurliniL.:Seismicpropertiesofmelt-generatingmetapelites

2.38 MisraS.,TumarkinaE.,BurliniL.,BurgJ.-P.:Rheologyofmetapelitesduringpartialmeltingandcrystallization

2.39 MoixP.,StampfliG.M.:Palaeotethyan,NeotethyanandPindosseriesintheLycianNappes(SWTurkey):geodynamicimplications

2.40 NagelS.,CastelltortS.,MouthereauF.,LinA.T.,WillettS.D.,KausB.J.P.:Newconstraintsonforelandbasindevelop-mentinSouth-WestTaiwanfromsequencestratigraphyandflexuremodelling

2.41 NegroF.,PelletC.-M.,BousquetR.,BeyssacO.,GuerraI.,VilsF.:ThermalstructureandmetamorphicevolutionofthePiedmont-LigurianmetasedimentsintheWestern-CentralAlps

2.42 NussbaumC.,BossartP.:InfluenceoffaultsonthedevelopmentofExcavationDamagedZone:thecaseoftheMontTerriRockLaboratory

2.43 PecM.,StünitzH.,HeilbronnerR.:Transitionfromfrictionaltoviscousdeformationingranitoidfaultgouges

2.44 PleugerJ.,MancktelowN.:StructuralobservationsfromtheInsubricfaultbetweentheValled’OssolaandValled’Orco(NWItaly)

2.45 RahnM.,WangH.:ApatiteFTdatafromtheTriassicSongpan-Garzêflysch,TibetanPlateau,NWSichuan,China

2.46 RamiA.,KahloucheS.,KhelifM.:DynamicTopographyDeterminationoftheWesternMediterraneanSeafromJason-1Data

2.47 RuizG.,SebtiS.,SaddiqiO.,NegroF.,StuartF.,FoekenJ.,StockliD.,FrizonDeLamotteD.:MirrordenudationpatternonbothsidesoftheCentralAtlantic–atraceofthePangeabreak-up?

2.48 SchenkerF.L.,BurgJ.-P.,GeryaT.: TheEasternPelagonianmetamorphiccorecomplex(northernGreece):Structureandmodels

2.49 SchmalholzS.M.:Formationoffoldnappesinductilemultilayers:insightsfromnumericalsimulations

2.50 SmitJ.,BurgJ.-P.,BrunJ.-P.:Twocriticaltapersinasinglewedge

2.51 TackleyP.,KellerT.,ArmannM.,vanHeckH.,NakagawaT.:Modellingthethermo-chemicalevolutionoftheinteriorsofMercury,Venus,Earth,Marsandsuper-Earths

2.52 ThielmannM.,KausB.J.P.:Anumericalapproachtotestlithosphericcross-sectionsforgeodynamicconsistency

2.53 ThustA.,HeilbronnerR.,StuenitzH.,TarantolaA.,HaraldB.: InteractionofH2Orichfluidinclusionsandnaturalquartzcrystalsindeformationexperiments

2.54 VandelliA.,VachardD.,MartiniR.,KozurH.W.,MoixP.,StampfliG.M.:TheLentasunitinSouthernCrete:thebaseofthePindossedimentaryseries?–Newpaleontologicalresults

2.55 VogtK.,Gerya,T.,CastroA.:ModellingofsilicicintrusionsinAlpinetypeorogens

2.56 ZhuG.,GeryaT.V.,HondaS.,TackleyP.J.,Yuen,D.A.:Influenceofthermal-chemicalbuoyancyin3-Dmantlewedge

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s 2.1

Tectonic history of the Lut Block in Nehbandan area, Eastern Iran

BagheriSasan*,ArefNejadMarzieh*&YabalouiMehdi*

*Department of Geology, University of Sistan and Baluchestan, Zahedan, 98135-674, Iran (sasan_bagheri@yahoo.com)

WeprovidenewconstraintsonthetectonicdevelopmentoftheeasternborderoftheLutBlockbasedonageologicalstudyoftheNehbandanarea(easternIran).Severaltectonicunitsandformationsprovideaninsightintothecompositetectonichistoryofthearea(Fig.1).TheDeh-SalmMetamorphicComplexmayberepresentaTriassic-Jurassic(orolder)accretionarywedge.Itcomprisespelites,psammitesandcarbonatesthatenclosesomebigolistholithes,anddeformedlayersofperidotite,basiclavasandpyroclastics.Athicksiliciclasticdeposit(shownongeologicalmapsoftheareaastheShemshakFormation)tectonicallyoverliestheDeh-SalmMetamorphiccomplex.Itiscomposedoflargevolumesofdeep-seafanturbidites,whichdepositedovertheeasternmarginoftheLutBlockbetweentheTriassicandJurassic.BothofaforementionedtectonicunitsdifferentlyunderwentaHT/LPmetamorphismuptomigmatizationgradesinthelateJurassic(Mahmoodietal.,2009),whichispossiblyrelatedtothearcmagmatism.TheShahKuhGraniteislateJurassicinageandpertainstoavolcanicarcthatdevelopedbetweenthemiddeandlateJurassicalonganorthward-dipping,Neo-Tethyssubductionzone.Shallow-watervolca-no-sedimentarysequencesexposedclosetoMighanvillage(NWNehbandan)(Griffisetal.,1992)areinterpretedtopertaintothe same arc. Since early Cretaceous the platform condition has governed on the eastern edge of the Lut Block up toPaleocene.TheNehComplexincludesanophioliticmélangeandmetamorphosedmarinesedimentaryrocksSenoniantoEoceneinage(Tirruletal.,1983).Igneousrocksfoundinthemélangearecharacterizedbysupra-subductionaffinities.WeinterprettheNehComplexasasecondaccretionaryprismemplacedalongthemarginoftheLutBlock.SynchronouswiththeanticlockwiserotationofthesouthernpartoftheLutBlockabout90°sincethePaleoceneuptotheMiocenebasedonpaleomagneticinvestigationsandtheIndian/Eurasiancollisionevent,themélangeandPaleogeneflyschoftheeasternLutjuxtaposedagainsttheAfghanblock.ContinuousconvergenceandshearingbetweentheLutandAfghanBlockssincetheLateEocenecreatedalargeandintensedeformationandgranitizationinaNW-SEright-lateralshearsystem.TheyoungesttectoniceventastheresultoftheArabian/EurasiancollisionmadesomemoreN-NEshearsystemssuchastheWestNeh,NosratAbad,andKahurakstrike-slipfaultsaswellasseveralNeogenepull-apartbasinsattheeasternmarginoftheLutblockwhichmayberesultedofreactivationoftheolderfaults.Recentseismicactivitiesaretheevidenceofcontinuousmovementofthelatesttectonicregime.

REFERENCES:GriffisR,MeixnerH, JohnsG,AbedianN,BehruziA,HosseinKhanNazerN,HamzehPourB, Shahriari S,BerberianM,

SoheiliM,SahandiMR,andMohajelM;1992:DehsalmQuadranglemap,Scale1:250,000,GeologicalSurveyof Iran,Tehran.

MahmoudiS,MasoudiF,CorfuFandMehrabiB,2009MagmaticandmetamorphichistoryoftheDehSalmmetamorphicComplex,EasternLutblock,(EasternIran),fromU-Pbgeochronology,InternationalJournalofEarthSciences,inpress.

Tirrul,R.,Bell,I.R.,Griffis,R.J.andCamp,V.E.,1983.TheSiatanSuturezoneofeasternIran.GeologicalSocietyofAmericaBulletin,94:134-150.

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Figure1.SimplifiedgeologicalmapoftheNehbandanarea.

2.2

Neogene tectonics of the Anarak area in Central Iran

BagheriSasan*,BuchsDavid**,SalariTayebeh*&NabaviMehdi*

*Department of Geology, University of Sistan and Baluchestan, Zahedan, 98135-674, Iran**Research School of Earth Sciences, Australian National University(sasan_bagheri@yahoo.com)

The Anaraq-Jandaq Terrane comprises a metamorphic assemblage of Carboniferous to Permo-Triassic accreted oceanicisland(s)andflyschsedimentsexposedalongthePaleo-TethyssutureinCentralIran(Bagheri&Stampfli2008).TheterranehasrecordedalongtectonichistoryrelatedtoearlyaccretionaryprocessesalongaPaleo-Tethysmargin,closureofthePaleo-Tethysandexhumationinthemid-Triassic,Neo-Tethyanback-arcevolutionand,finally,Neogeneeventsthatarethefocusofthisstudy.TheAnaraq-JandaqTerraneislocatedalongtheeasternborderoftheArdakan-KashanLinethatextendsparal-leltotheZagrosThrustintheback-arcareaoftheNeo-TethysUromieh-Dokhtarvolcanicarc(Fig.1).TheLinehasbeenin-terpretedasadextralshearzoneofregionalsignificance(Bagheri,2007),butadditionalconstraintsarestillneededtobetterunderstanditsroleinthetectonicevolutionofCentralIran.

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s StructureseastoftheArdekan-KashanLinedisplayseveralright-steppeden-echelon,double-plungedtohalffoldsthatformhelicoidal-shappedpatternsonamapview(Fig.1).Largefoldsandsyntethicandantitheticconjugatestrike-slipfaultsoccurinbasementrocks(e.g.Sylvester,1988),whicharealsofoundintheAnarakarea.Thelargestdextralstrike-slipfaultsystemintheAnarak-JandaqareacorrespondstotheNW-SEAnarakShearZonethatishighlightedbyadismembermentofaccretedsequencesofoceanicisland(s).TheNE-SWDorunehFaultisthelargestsinistralstrike-slipfaultintheareaandinterfereswiththeAnarakShearZone.Twolargeen-echelonmega-halffoldswithnearlyE-Waxialtracehavebeenrecognizedbetweenthefaultandtheshearzone.FormationofthesefoldslikelypostdatesformationofadoubleplungeantiformfoundintheAnarakarea.TheAnarakareaischaracterizedbyarecentantiformalpop-upstructure(positiveflowerstructure)thatcom-prisesseveralupwarddivergingthrustedsheetsofmetamorphicrocksandTertiarysediments.

BasedonprecedingobservationswedividedtheAnarak-JandaqTerraneandadjacentareasintosevenstructuraldomainsthatprovideaninsightintorecenttectonics.OurpreliminaryresultssupportinterpretationoftheArdakan-KashanLineasa dextral shear zone and suggest that Neogene strain concentrated east of the line as a result to convergence betweenArabianandIranianplates.TheconvergenceledtoformationoftheAnarakpop-upstructureandtoreactivationoftheex-humationoftheAnarak-JandaqTerrane.

Figure1:NeogenefaultsandfoldstrikesintheAnarakarea.a)Tectonicsettingofthestudiedarea.b)Stereographicprojec-tionof faultplanes in thenorthernAnarakarea (polesof fault, lowerhemisphereequal-area). c)Spatialarrangementofstructuresassociatedwithanidealizedright-slipfaultafterChristie-BlickandBiddle(1985).

REFERENCES:Bagheri, S. 2007: The exotic Paleo-Tethys terrane in central Iran:newgeologicaldata fromAnarak, Jandaqandposht-e-

Badamareas,unpublishedPh.D.thesis,UniversityofLausanne,Lausanne,Switzerland,223pp.Bagheri,S.,&Stampfli,G.M.2008:TheAnarak, JandaqandPosht-e-Badammetamorphiccomplexes incentral Iran:New

geologicaldata,relationshipsandtectonicimplications,Tectonophysics451:123–155.Christie-Blick,N. andBiddle,K.T., 1985.Deformationandbasin formationalong strike-slip faults. In:K.T.Biddle andN.

Christie-Blick (Eds.), Strike-slipdeformation,basin formation, and sedimentationSocietyofEconomicPaleontologistsandMineralogistsSpecialPublication,p.1-34.

Sylvester,A.G.1988:Strike-slipfaults,GeologicalSocietyofAmericanBulletin,100:1666-1703.

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Khur platform: Tectonic evolution of a part of the Neo-Tethyan back-arc basin in Central Iran

BagheriSasan*,StampfliGerard**,MoixPatrice**&BakhshiMohammadReza*

*Department of Geology, University of Sistan and Baluchestan, 98135-674 Zahedan, Iran**Institute of Geology and Paleontology, University of Lausanne, 1015 Lausanne, Switzerland

Tectonically,theKhurregionintheNWmarginoftheCentral-EastIranianmicrocontinent(CEIM)andattheNEsideoftheUromieh-DokhtarmagmaticarcisanexceptionalareawheretheNeo-Tethyanback-arcrifting,driftingandcollisionalstageeventsarewellpreservedintheLateJurassic-Eocenedepositsandsynchronousigneousandmetamorphicrocks.Noequiva-lentsofsuchathickdepositareknownfromcentralIran(Aistovetal.,1984;Bagheri,2007).SouthoftheBiabanakfaulttheterrestrial rift-related Upper Jurassic-Lower Cretaceous Chah Palang and Noghreh Formations unconformably cover theVariscan-Eocimmerianmetamorphicrocks(BagheriandStampfli2008)andfollowedbyanenormousthickflyshoiddeposit(thepost-riftBiabanakshale).TheAr/ArformicasandU/Pbforsingle-grainzirconsrespectivelyrelatedtothemetamorphicandigneousrocksyieldtheLateJurassiccoolingages(Bagheri2007).ThesecondriftingstageoccurredsouthoftheDorunehFault;there,theJandaqigneous-metamorphiccomplexthatformedthebasementofthetiltedblocksisfoundbelowtheearlyLateCretaceoussyn-riftformationsuchasDebarsu.FewtensofkilometerstowardthenortheastintheKharTuranarea,theearlyCretaceousmildlyalkalinebasaltandorbitolinalimestonesequencestransitionallychangetotheLateCretaceouspelagicdeposits.Weconsiderthissequenceasaresultofsedimentationontheedgeofaninfantoceaniccrust.Thissequen-ceisfollowedbyLateCretaceous-PaleoceneHaftooman,FarrokhiandChupananformationsmainlycomposedofbenthictopelagicmarlandlimestoneintheKhurarea;thesenearly3000metersmarinedepositssetdownwhentheKhurplatformwas being developed during the drifting stage. The thick Eocene-Oligocene flysch of Pish Kuh accompanied by the LateCretaceous-PaleoceneophioliticmélangesofNain-Ashinaswellascalc-alkalinevolcanicrocksunconformablyoverlietheplatformsequenceneartheDorunehFault.Thisassemblagecouldbetheproductsofback-arcclosurecomparablewiththeLate Eocene-Oligocenemélange-type rock collections surrounding the CEIM (collisional stage). TheOligocene Lower RedFormationcanberegardedasthemolasseofthisclosureevent.TheKhurplatforminviewpointofstratigraphyandpaleo-ntology isvery similar to the time-equivalentbasinsuchasKopehDaghandtheNorthAfghanplatforminNE Iran; thepresenceoftheKhurplatforminCentralIrancouldbetheconsequenceofcounter-clockwiserotationoftheCEIMsincetheEocenetimecontemporaneouswiththeIndian-Eurasiancollision.

REFERENCES:Aistov, L.,Melanikov,B.,Krivyakin,B.,Morozov, L. andKiristaev,V. (Eds.), 1984.Geologyof theKhurArea (central Iran),

ExplanatorytextoftheKhurquaderanglemap1:250,000.GeologicalSurveyofIran,V/O"Technoexport"USSRMinistryofGeology,Reports,TE/No.20,1-132,Moscow.Bagheri, S. 2007: The exotic Paleo-Tethys terrane in central Iran:newgeologicaldata fromAnarak, Jandaqandposht-e-

Badamareas,unpublishedPh.D.thesis,UniversityofLausanne,Lausanne,Switzerland,223pp.Bagheri,S.,&Stampfli,G.M.2008:TheAnarak, JandaqandPosht-e-Badammetamorphiccomplexes incentral Iran:New

geologicaldata,relationshipsandtectonicimplications,Tectonophysics451:123–155.

Figure1:CrustalevolutionmodelforAtlantic-typemarginsutilizedforcrustalevolutionoftheKhurplatform.(NextPage)

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Tectonic control of Pb-Zn-Ba-(Sr) deposit at Oued Jebs-Kef Lasfar, nort-hern Tunisia

JaloulBEJAOUI*,AhmedSELLAMI**

* Centre National des Sciences et Technologies Nucléaires, Tunisie, bjaoui_geo@yahoo.fr ** Office National des Mines, Tunisie

TheOuedJebs-KefLasfarPb-Zn-Ba-(Sr)mineralizedareaislocatedinthenorthernTunisia(60KmfromTunis)andformspartofthediapirzone(Fig.1)whichishighlyaffectedbyNNW–SSEtrendingtectonicdeformation(Fig.2).Thestructuralanalysiscarriedout intheOuedJebs-KefLasfardepositrevealstheexistenceofonetectonicphasecharacterizedbyaNW-SE (σ1)maximumcompressionorientationandNE-SWmaximumextensiontrending.ThePb-Zn-Ba-(Sr)mineralizationoftenfillsfracturesinthecalcitematrixwithinthemassivelimestone.ThePb-Zn-Ba-(Sr)eventmineralizedstructuresarerelatedtotheNW-SEcompressiveeventpresumablyassociatedtoAlpineconvergence(BenAyed,1986).Fieldobservationsshowsomerelativechronologycorrespondingtosuperimposedstriationsonfaultsurfacesandcross-cuttingrelationshipsbetweenstructures(faults,joints,calciteveins)(Fig.2).TheCenomanian-TuroniancarbonatesoftheOuedJebs-KefLasfarhavebeensubjecttoseveralstylolitisationprocessesandfracturingevents,beingsubsequentlyfilledbyvariouscalcitecements.Basedonthedescribedstructuresandontheregio-nalgeologicalframe,weassumethatveinswerereultedfromtheNE–SWextension.Theseextensionalstructuresarecrucialsitesforthelocalizationoffluidflowandoredeposition.SuchorebodiesemplacementsareassociatedwithdiapirsandareinterpretedastheresultofaSerravalian-Tortoniangravity-drivenfluidcirculationeventrelatedtolateAlpineconvergence(Decreeetal.,2008).

REFERENCESBenAyed,N.,. (1986)- Évolution tectoniquede l’avant-paysde laChaîneAlpinede laTunisiedudébutduMésozoïqueà

l’Actuel.ThèseDoctoratèsSciences,UniversitéParis-Sud(inédit).SophieDecrée,ChristianMarignac,ThierryDePutter,EtienneDeloule,Jean-PaulLiégeoisandDanielDemaiffe.(2008)-Pb–

ZnmineralizationinaMioceneregionalextensionalcontext:ThecaseoftheSidiDrissandtheDouahriaoredeposits(Nefzaminingdistrict,northernTunisia).

Fig1.LocationoftheOuedJebsoredepositwithinthediapirszoneinTunisianstructuralmap.

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Fig.1-(A)and(B)Cenomanianlimestoneaffectedbyaminornormalfaultassociatedwithextensionalfentescollapsedwithcalcite,(C)sub-

parallelsveinsfilledwithgalena,(D)Cenomanianlimestonewithtwoveinsgenerations-filledwithgalena.

2.5

Polymineralic Mylonites Generated by Chemo-Mechanical Mixing: The Glarus Thrust as an Example

Th.Buckingham,M.Herwegh,O.A.Pfiffner

Institute of Geological Sciences, Bern University, Switzerland

Large-scaleshearzonesoftenarecharacterizedbydifferentrocktypesinthehangingandfootwall.TheGlarusthrust,asanexample,definesasharplithologicalboundarybetweenPermianVerrucanointhehangingandInfrahelveticsedimentaryunitsinthefootwall,separatedbyalayerofLochsitencarbonate-tectonite.Thesetectonitesareusuallymixturesofsilicateandcarbonatephasessuggestingincorporationofcomponentsfromfootwallandhangingwall.Inthisway,polymineralictectonitesevolvewithongoingdeformation,becomingmoreandmore impureowing to twodifferentmixingprocesses:fluid-assisted(i)predominantlymechanicaland(ii)combinedchemo-mechanicalmixing.(i)Inthecaseofpuremechanicalmixingonthemeso-scale,brittlefracturingandtheformationofmicroshearzonesobliquetotheshearplaneallowshearingofsurroundinghostmaterial intothecarbonatetectonite.Thus,hybridtectonitesmayevolvewithviscousgranularflowinducingafurther,dispersed(seeii)mechanicalmixing.IntheLochsitencarbonate-tecto-nitesynkinematiccalciteveinssuggestthatthisprocessmusthaveoccurredunderthepresenceoffluids,whichmayhaveenhancedtheformationofthebrittlefracturesbyhydrofracturing.(ii)Chemo-mechanicalmixingisbasedonthedissolutionofmineralphasesthatareunstableinthesurroundinghostrocks.Theactivityofgranularflowinthefaultrockhastwoimportanteffects:Firsttheformationofgrain-scalecavitiespromotesthepumpingofsurroundingfluidsintothetectonite,followedbyprecipitationofsecond-phasemineralsinthenewlyfor-medcavities.Inthisprocess,homogeneousmixturesoffine-grainedcalcitematrixandsilicate(e.g.feldspars)second-phasesdevelop.Purecalcitemylonitesformedintheaforementionedsynkinematicveinsbecomecontinuouslyimpurifiedbythetwomi-xingprocesses,whichallowsgranularflow(diffusioncreep)todominatedeformation.Bothobservedprocessespersistduri-ngtheactivityofthelarge-scaleshearzoneasafunctionofsurroundingwallrocksandlocalfluidavailability.Withongoingexhumationinduced-cooling,however,strainismorelocalizedandtheactiveshearzonebecomesnarrower.Ourobserva-tionssuggestthatthesetwosuggestedmixingprocessesareactiveuntilthefinalstagesofthrustingwhenbrittleconditionsprevail.

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The thermochemical nature of the upper mantle: an interdisciplinary approach

FabioCammarano*,PaulTackley*,TakashiNakagawa*,LarsStixrude**,CarolinaLithgow-Bertelloni**,WenboXu***,BarbaraRomanowicz****

*ETH Zürich, Institute of Geophysics, Geophysical Fluid Dynamics**University College London, Earth Sciences***Michigan University, Earth Sciences****UC Berkeley, Earth Science, Berkeley Seismological Laboratory

Mostoftheuppermantleisinaccessibletodirectsamplinganditsphysicalconditionsareindirectlydeterminedfromtheinterpretationofseismicdatabasedoninsightsfrommineralphysics.Theconjectureoftheuppermantleasawell-mixed,homogeneouscompositionhasbeenrecentlychallengedfromanewfamilyofgeodynamicmodelswhichincludesatwo-phase(MORBandHarzburgite)mixturewhichdoesnotequilibrateduringmantleevolution(e.g.,Tackleyetal.,2005).Theco-existenceofseparatedrockassemblagescannotbediscarded,indeed,consideringthelowchemicaldiffusivitiesofmantlematerials.Atthesametime,thephysicalinterpretationoflongperiodseismicwaveformsfoundthatcompositionshouldchangewithdepth(below~250km)ataglobalscale(CammaranoandRomanowicz,2007).Here,weshowtheresultsofarecentre-interpretationofglobalseismicdatabasedonastate-of-the-artmineralphysicsmodel.Themodelisbasedonknowledgeofmaterialpropertiesathightemperaturesandpressures.Inparticular,elasticpropertiesarecomputedwitharecentself-consistentthermodynamicalmodel,basedonasixoxides(NCFMAS)system.WemodeltheP,TandfrequencydependencyofanelasticitybyusingthemodelQ5(Cammaranoetal.,2003),basedontheArrheniuslawasexpectedofthermallyactivatedprocesses.Weadoptanon-linearproceduretoinvertnormalmodesforpossiblethermalorcompositionalstructuresoftheuppermantle.WeconsiderbothequilibriumassemblagesandmechanicalmixturesofMORBandHarzburgite.WefoundfurtherevidencethatcompositionshouldbecomericherinMORBcontentbelow250kmandwefoundthatonlyamechanicalmixture isabletofit theseismicdata.Standingtoourmineralphysicsmodel, therequiredcompositionalgradientwithdepthiseventoohigh(forrealisticthermalstructures).Anincreaseingrainsizewithdepthcouldplayroleaswell.Futureworkwillpushevenfurthersuchaninterdisciplinaryapproach,tryingtoextendourinterpretationtoothergeophysicalobservablesandcoupletheresultswithmodelsofthethermochemicalevolutionoftheuppermantle.

2.7

Tectonics of the western Gran Sasso d’Italia (Central Apennines)

GiovanniLucaCardello*,DanielBernoulli**&CarloDoglioni***

* ETH-Zürich, ** Basel University, *** Sapienza University, Rome,

DuringJurassic-Cretaceoustimes,theareaofthecentralApennineswaspartofalarge,Bahamian-typecarbonateplatform–basinsystem,wherebytheareaoftheGranSassowassituatedbetweenthecarbonateplatformofLatiumandtheAbruzziinthewestandthedeepbasinalareaofMarche-Umbriatotheeast.Thistransitionalareaexperienced1.EarlyJurassicriftingof theAdriaticmargin, leadingtotheopeningof theLigurianbranchofTethys;2.prolongedthermalsubsidenceof thecarbonate-platformslopeandbase-of-slopeintheJurassic–Cretaceous;3.decollementalongTriassicevaporates,thrustingand foldingduring theNeogene formationof thearcofGranSassoand4.post-nappenormal faultingpersisting to thisdate.MappingofthewesternpartoftheE–W-trendingridgeoftheGranSassod’Italia,thehighestelevationoftheApennines(2914m),hasyieldedthefollowingresults:1–TheearlyJurassicriftingeventledtothesegmentationoftheplatformslopeintostructuralhighs(CornoGrande,MonteandAcquaSanFranco)andbasins(PizzoIntermesoli,M.Corvo)assuggestedbythepronounceddifferencesinthicknessoftheearly–middleLiassicsyn-riftsediments(CorniolaFormation).WhereastheAcquaSanFrancostructuralhighinthewestwasburiedduringtheToarcian,theCornoGrandehighintheeastpersistedthroughoutMesozoictimesatleastintotheearlyTertiary.The longevityandpossible tectonicreactivationof thesubmarinetopography, inheritedfromearlyLiassicrifting,persistedwayintoJurassic–CretaceousassuggestedbythepronounceddifferencesinthicknessoftheJurassic(Corno

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s PiccoloFormation)andCretaceous (CefaloneandM.CorvoFormations)base-of-slopesedimentsderivedfromtheAbruzzicarbonateplatform,andsequencespunctuatedbystratigraphicgapsonthehighs.2–DuringtheTertiaryorogenyoftheApennines,theinheritedMesozoicstructuresevolvedintoN-Strendingtransferzonesbetweentheindividualthrustsandfoldsover-andunderthrustingthemoreexternalLaga unit.Theaxisofthefrontalanti-clineandtherelatedthrustofGranSassoplungewestwardwithaparalleldecreaseinshortening.Thetiplineoftheblindthrust related to the frontal fault-propagation foldbecomesdeeperandmore internalmovingwestward, according toagradualtransferofshorteningtowardtheadjacentrecess.TheE-WtrendingarmoftheGranSassoarcexperiencedacom-ponentofleft-lateraltranspressionasexpectedfromtheNE-wardpropagationofthecentralApenninesaccretionarywedge.Thepropagationof thearcoccurredduringdepositionof theMessinianLagaFlyschFormationas shownby thegrowthstructuresinthelatter.3–Thebacklimbofthefrontalfault-propagationfoldindicatesthattheentirestructurehasbeentiltedafteritsdevelop-ment.Wespeculatethatthishasbeengeneratedbyadeeperrampofabackthrust,formingatrianglezoneaffectingtheentireE-WtrendingGranSassorange.Thiswouldexplaintheabout15kmlong,regionallydiffusemonoclineoftheGranSassorangetowardtheforeland.4–Normalfaultscutacrossthepreviouslytiltedinternallimb,asshownbythecut-offangleofthefaultsrelativetobedding;Mostofthemshowmorphologicevidenceofpresent-dayactivity,butonlypartofthedisplacementobservedisduetothePleistocene-Holoceneextensionbecauseofthepoly-phaseroleofthemainfaultsystems.Accordingtosurficialfaultruptureheight,theTre SellenormalfaultasmostoftheothernormalfaultscouldgenerateearthquakesofMw>6.5.TheTre Selle faultisclearlylinkedtotheAssergi FaultbytheCampo Imperatore Faultthathastranstensivecharacteristicsandanen-échélonori-entation,functioningasalinkbetweenthetwoformerfaultsystems.

2.8

Neogene transtensional tectonic evolution of the central Helvetic nappes: preliminary results

GiovanniLucaCardello*&NeilMancktelow*

* Geologisches Institut, ETH-Zürich, CH-8092 Zürich

TheHelveticnappestackintheRawyldepressionbetweentheAarandMontBlancmassifsisaffectedbyobliquetranstensi-onalnormalfaultsdevelopedorreactivatedduringtheNeogene.OnefieldseasonofmappingofthemainfaultstructuresintheRawyl-Audannesareahasprovidedthefollowingmainresults.1.Threepreferentialorientationsnormalfaultsetsareobserved,strikingE-W,NW,andNE.2.TheNE-strikingsetdipsmainlytotheSEand,fromrelativeagerelationshipsofassociatedveins,istheoldest.PaleotectonicfeaturesexposedinPlainedesRoses,PlaineMorteandLesAudannessuggestthissetwasalreadyactiveduringCretaceoussedimentation. TheUpper Cretaceous stratigraphic sequence is influenced by paleo-escarpments that clearly define theorientationofthepaleo-faults.Thesesurfacesaremarkedinmanyplacesbykarstificationandsilicificationofthesurface,sedimentarydykesandtheonlapofbasinalyoungerformations.SomeofthesefaultshavebeensubsequentlyreactivatedduringNeogenesyn-andpost-collisionalextension.3.TheE-WandNW-strikingsystemslocallyshowaninitialmyloniticshear-zonestageoverprintedbycataclasticfaulting,especiallyinmorecompetentunitssuchastheSchrattenkalkFm.4.TheE-WandNW-strikingfaultswerebroadlycoeval,as indicatedintheRawyl-PlaineMorteareabymanyexamplesofbranchingandbendingofonesetintotheotherandbythesimilardisplacementdirections.5.CalciteslickenlinesandfibresontheNeogenefaultplanesindicatetwomainstretchingdirections.TheolderoneisWSW-directedandgenerallyplungesaround30°,whereastheyoungeroneplungestothesouth,withasteeper,mainlydip-slipmovement.6.Crosscuttingveinrelationshipsandbendingofveintailsplanesindicateacounter-clockwiserotationofthestretchingdirection,fromWSWtowardS.7.TheWSW–directedorogen-parallelstretchingissimilarinorientationtothatassociatedwiththeSimplon-RhoneFaultZoneandisprobablycoeval,implyingpossibleactivitythroughoutmuchoftheMiocene.

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Sedimentology of Early Pliocene Sandstones in the South-Western Taiwan foreland: implications for basin physiography at the onset of col-lision.

CastelltortSébastien*,NagelStefan*,MouthereauFrédéric**,LinAndrewTien-shun***,WetzelAndreas****,KausBoris*,WillettSean*,ChiangShao-ping***&ChiuWei-Yi***

*ETH-Zürich, Sonneggstrasse 5, 8092 Zürich (sebastien.castelltort@erdw.ethz.ch)** Université Pierre et Marie Curie, Place Jussieu, 75252 Paris*** Basin Research Group, National Central University, Jonghli, Taiwan**** Geological and Paleontological Institute, University of Basel, Bernoullistr. 32, 4056 Basel

Forelandbasinsdevelopatthefrontoforogensandarefilledbysedimentsderivedfromtheerodingmountainrange.Assuch,theirstratigraphicarchitectureandsubsidencehistorycontainarecordofmountainbuilding.InTaiwan,thewesternforelandbasinresultsfromtheflexureoftheEURlithosphereprovokedbythrustloadingofunitsontotheChinesemargin.Fieldwork,seismicprofilesandboreholedataacquiredbyoilcompaniesdocumentextensivelythedevelopmentofthebasin(Linetal.,2003).Itiscomposedofasuccessionofstagesrecordingtheprogressivefillingofthebasinafteranunder-filledstageattheinitiationofload-inducedsubsidence.ThisgeneralsequenceoffaciesinTaiwanisattheoriginoftheclassicalmodelofforelandbasinfillingsequencepopularizedbyCovey(1986)inaspecialIASvolumeonForelandBasinsandhassincebeenappliedworldwide.However,whiletheunder-filledstagecanbeclearlyrecognisedonthefield,thepre-forelandseries(earlyKueichulinandbefore)andtheassumedearlyforelandseriesthatcanbeobservedonthecratonwardsideofthebasinbothindicaterelativelyshallowwaterenvironmentsandarebothfedbytheChinesemarginthroughtheirhistory.Thus,noobviouschanges in sedimentaryenvironmentsandcompositionclearlymark the initiationof subsidence.Thisproblemisalsoreflectedinthedifferentagestowhichdifferentauthorsattributetheinitiationofforelandbasinsubsi-dence.WhenandwheredidtheloadinducedsubsidencestartinTaiwan?ItiscrucialtosolvethisissuebecauseitconditionsourunderstandingofthetectonichistoryofcollisioninTaiwan,thetype-orogenfortheoriesofcriticalwedges.

TheBasinResearchgroupinTaiwan,TectonicslaboratoryinParisandbothGeophysicalFluidDynamicsandEarthSurfaceDynamicsgroupsatETHtacklethisissuetogetherandfromdifferentapproaches.

In thisworkwepresentour sedimentological analysisof thePlioceneTawoandAiliachao sandstones in theYujingandYucyongpingareas,situatedatornearthetransitionfrompassivemargintoforelandbasinsubsidence.Weshowthattheyprobablycorrespondtohyperpycnalturbiditesinrelativelyshallowwaterpro-deltaenvironmentssimilartomoderndepositionintheYellowSea.Throughtime-seriesanalysisofrhythmicbedsweshowthataremarkablefeatureisthestrong,potentiallymisleading,influenceoftidecurrentsinshapingthesedeposits.Weincorporatetheseinformationsintorestoredpaleogeographicalhypothesesforthistimeperiodusingestimatedquantitiesofshorteningintheforelandfold-and-thrustbeltandshowthattheChinesecontinentalmarginatthistimedisplayedanimportantpromontorytowardstheocean.Thiscouldexplainwhythecollisionseemstohavestartedbeforethanusuallyinferredbasedonreconstructionsassumingacylindricallinearcontinentalmarginandextrapolatingtothepastthemodernhigh-ratesofconvergence.

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Figure1.Detaileddescriptionofachannel-leveesysteminshallowturbiditesoftheAiliaochaoformationinthePlioceneofsouth-central

Taiwan.

REFERENCESCovey,M. (1986) - Theevolutionof forelandbasins to steady state: evidence from thewesternTaiwan forelandbasin, in

ForelandBasins,editedbyP.A.AllenandP.Homewood,Spec.Publsint.Ass.Sediment.,8,77–90.Lin,A.T.,WattsA.B.&HesselboS.P.(2003)-CenozoicstratigraphyandsubsidencehistoryoftheSouthChinaSeamarginin

theTaiwanregion.BasinResearch,15(4),453-478.

Funding:ThisprojectisfundedbySwissNationalFundsgrant#2-77295-08.

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One-sided subduction in self-consistent models of global mantle convection: the importance of a free surface and a weak crustal layer

CrameriFabio,TackleyPaul,MeilickIrena,GeryaTaras,KausBoris&KellerTobias

Institut für Geophysik, ETH Zürich, Switzerland (fabio.crameri@erdw.ethz.ch)

Previousdynamicalmodelsofglobalmantleconvectionindicatedthatavisco-plasticrheologyissuccessfulingeneratingplatetectonics-likebehaviourself-consistently(Moresietal.,1998;vanHeckandTackley,2008).Yet,thesemodelsfailtocre-ateEarth-likeplatetectonics:sofarinallpublishedmodelssubductionistwo-sidedandmoreorlesssymmetric,whereasterrestrialsubductionisone-sidedandcharacterizedbyadistinctiveasymmetry.

Figure1.Viscosityfieldsforconvectionwithastronglytemperature-dependentvisco-plasticrheologyand(top)afreesurfaceor(bottom)a

free-slipsurface.

Onesimplificationusedinpreviousmodelsisthatofafree-slipupperboundary,inwhichtheshearstressiszerobuttheverticalpositionoftheboundaryisfixed.Incontrast,subductionzonesdisplaysomeofthelargestvariationsinsurfaceto-pographyonEarth.Forthecaseofaslabthatisinitiallyplacedatthesurfaceandallowedtofreelysubduct,Schmelingetal.(2008)showedthatitisnecessarytoincludeaproperfreesurfaceinnumericalmodelsinordertoreproducelaboratoryresults.Accordingtotheirbenchmarkstudy,mimickingafreesurfacebyalowviscosity,zerodensitylayerontopofthecrustisanadequateapproach.Forthisreason,wehaveimplementedsucha"stickyairlayer"inourglobalnumericalmo-del.

Weherestudytheeffectofafreesurfaceonthemodeofsubductionin2Dand3Dglobal,fullydynamicmantleconvectionmodelswith self-consistentplate tectonics. For thisweuse thefinite volumemultigrid codeStagYY (Tackley, 2008)withstronglytemperature-dependentviscosity,ductileand/orbrittleplasticyielding,andnon-diffusivetracerstrackingcomposi-tionalvariations(the'air'layerinthiscase).

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s Weobserve that indeed,a free surface leads to single-sidedsubduction,whereas identicalmodelswitha free slipupperboundarydevelopdouble-sidedsubduction(Figure1).Afreesurfaceisthusanessentialingredienttoobtainrealisticsub-ductionbehaviourinnumericalmodels,probablybecauseitallowstheslabtobendinanaturalmanner.

Althoughtheabovemodelsappearone-sidedfromthetemperatureorviscosityfields,thereisstrongmechanicalcouplingbetweentheslabandthemantlewedgethatmakesthemmechanicallydouble-sided.Regionalmodelsofsubduction(Geryaetal,2008) indicate thatonerequirement forstableone-sidedsubduction isa lowstrength interfacebetweentheplatesachievedbythepresenceofmetamorphicfluidsinthesubductionchannel.Suchalubricationlayerconsistingofweakhy-dratedsedimentsaccommodatesstableone-sidedsubductionbystrainlocalization,whiletheabsenceofaweakshearzoneleadstomechanicallytwo-sidedsubductionsinceinthiscasetheplasticstrengthoftheentireplatesneedstobesufficientlylowtoallowforsubduction.

Inconclusion,afreesurfaceisthekeyingredienttoobtainthermallyone-sidedsubduction,whileadditionallyincludingaweakcrustisessentialtoobtainsubductionthatisbothmechanicallyandthermallyone-sided.

REFERENCESMoresi,L.,&SolomatovV.1998:Mantleconvectionwithabrittlelithosphere-Thoughtsontheglobaltectonicstylesofthe

EarthandVenus.Geophys.J.Int.133,669-682.vanHeck,H.&TackleyP.J.2008:Planformsofself-consistentlygeneratedplatetectonicsin3-Dsphericalgeometry.Geophys.

Res.Lett.35,doi:10.1029/2008GL035190.Schmeling,H., BabeykoA., EnnsA., FaccennaC., Funiciello F.,GeryaT.,GolabekG.,Grigull S., KausB. J. P.,MorraG.,

Schmalholz S.& vanHunen J. 2008:Abenchmark comparisonof spontaneous subductionmodels – towards a freesurface:Phys.EarthPlanet.Int.171,198-223.

Tackley,P.J.2008:Modellingcompressiblemantleconvectionwithlargeviscositycontrastsinathree-dimensionalsphericalshellusingtheyin-yanggrid.Phys.EarthPlanet.Int.,doi:10.1016/j.pepi.2008.08.005.

Gerya,T.V.,ConnollyJ.A.D.&Yuen,D.A.2008:Whyisterrestrialsubductionone-sided?Geology36,43-46.

2.11

Parameters that control the formation of lithospheric-scale shear zones

CrameriFabio*,KausBorisJ.P.*&TackleyPaulJ.*

*Institute of Geophysics, ETH Zurich, Schafmattstrasse 30, CH-8093 Zürich (fcrameri@student.ethz.ch)

Shear-heating induced localizationmightbean importantprocess for subduction initiation.Kaus&Podladchikov (2006)showedwith the help of numerical simulations that for some parameters, localization occurs and for other parameterchoices,localizationdoesnottakeplace.Thereby,eitherhomogeneousthickeningorbucklingcompensatesthedeformati-on.Thermallyactivatedthrustingincontrasttothesetwomechanismsispreferredforarelativelycoldlithosphere.Inaddi-tiontothethermalstructureofthelithosphere,thedeformationmodeisalsodeterminedbytheinitialrheologicalstruc-tureandbytheshorteningrates[Burg and Schmalholz,2008].Here,numerous2-Dsimulations(>100#)areperformedtodistinguishtheseregionsbychangingtheparametersthatinflu-encetheshearheatingprocess.The2-DsimulationsareperformedusingaMATLAB-basedfiniteelementcode.Thestandardsimulationsusedforthisworkmodelalithosphereconsistingofanuppercrust,alowercrustplusanuppermantlepart.First, only temperatureand strain rateare changedduring systematic simulations, followedby changes in the rheology.Additional2-Dsimulationshavebeenperformedinwhichthemantlethicknesswasincreasedorinwhichtheinitialgeo-metry(forexamplecrustalthickness)waschanged.Inaddition,afast1-Dfinitedifferencecodewasdeveloped,thatexactlyreproducestheresultsofthe2-Dcodeforlaterallyhomogeneouscases.Forthesameinputparameters,itcomputesinformationoftemporalchangesofboththetemperatureandstrengthprofileoftheEarth’supperpartduetoshear-heating.Evenmoreimportant,itfurthersuppliesinformationfortheoccurrenceoflocalizationaftercomparingandvalidatingitsresultswiththe2-Dsimulations.Asapowerfultool,this1-Dcodecanfinallybeusedtopredicttheoccurrenceofshearlocalizationforgiveninputparameters.Thisthusyieldsnewinsightsintheoccurrenceofshearlocalizationinacompressedlithosphere.

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Figure1.Localizationpredictionof1-Dcode(redarea)arecomparedto2-Dsimulationresultsshownaspointsandindicatingnolocaliza-

tion(blue),localization(red)andunknown(green).

REFERENCESBurg, J. P., andS.M. Schmalholz (2008),Viscousheatingallows thrusting toovercomecrustal-scalebuckling:Numerical

investigationwithapplicationtotheHimalayansyntaxes,EarthandPlanetaryScienceLetters,274(1-2),189-203.Kaus, B. J. P., and Y. Y. Podladchikov (2006), Initiation of localized shear zones in viscoelastoplastic rocks, Journal of

GeophysicalResearch-SolidEarth,111(B4).

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Twin meteorite impact craters in Thessaly (Central Greece) of Holocene age

DietrichVolkerJ.*&GartzosEfthimios**

*Institute for Mineralogy and Petrography, Swiss Federal Institute of Technology, CH-8092 Zurich, Switzerland (volker.dietrich@erdw.ethz.ch)**Laboratory of Mineralogy-Geology, Agricultural University of Athens, GR-118 55 Athens, Greece

Twocircularpermanentlakesof150and250mindiameterand12and16mdepth,respectively,occur250mapartfromeachotherintheagriculturalfieldsSWofthetownofAlmyros(Thessaly).ThebasementbeneaththealluvialcoverconsistsofMesozoicmarly limestones, schists,phyllites, cherts,aswellasof slicesof radiolarites, serpentinitesandmeta-basalts(Marinosetal.1962).ThelakeswereregardedasdolinesduetotheoccurrenceofkarstphenomenaintheequivalenttectonicunitsinthesurroundingOthrismountains.Anotherhypothesisasvolcanicmaar-typediatremeshasbeensuggestedonthebasisoftheexistenceofsmallCenozoicvolcaniccentersinthewiderarea(Marinou1962),howeverwithoutanyevidenceforejectedvolcanicmaterial.Thesuspicionofanoriginduetometeorite impactarosewiththeavailabilityofahigh-resolutionGoogleearthsatelliteimage.Thelakesexhibitsignificantsickle-shapedhalosupto30mhigh.TheagesofthelakescanbeassumedontheirfreshmorphologicalcharacterasHoloceneandbracketedbetweenapproximately12500and9000to7000yearsBP;thelatteragecomesfromremnantsofanEarlyNeolithicsettlementadjacenttothelargerlake(Papathanassopoulos1996).

Duringtworeconnaissanceinvestigationsaconsiderableamountofangulartoroundedpebbleswerefoundinthesandy-siltyclayoftheshoresaswellasinthehalos.Novolcanicmaterialwasfound.Theangulartoirregularroundedyellowishtoorangeandpartiallyblack-coatedpebblesvaryfrommmtoapproximatelyonedecimeterinsize.Theyaremadeupof:heterogeneouscarbonaceousfine-breccias,moreorlesshomogeneouscarbonaceouspebbles,infewcaseswithfusiformandconeshapesaswellasquartz,redradiolarite,andveryoccasionallyserpentiniteandmeta-basaltfragments.

Texturesthatcanbeinterpretedasevidenceforshock-meltedcarbonates(e.g.inGraup1999;reviewinOsinskietal.2008):1) Carbonate quench textures.

The homogeneous carbonaceous grains and pebbles display distinctive feathery (spinifex) textures of calcite. They are coarser towards the inner parts and progressively finer towards the rims. In addition, fine spinifex crystals cover the walls of “spider-type” radial and concentric cracks, which originate from the inner parts of the pebbles and are fil-led with euhedral calcite. Many fine spherules (< 100 µm to a few mm) are entirely filled with feathery calcite.

2) CarbonatespherulesManyfine-brecciascontainnumerouscarbonatespherules,whichoccurasindividualspherulesandshowinseveralcasescoalescentbounding.Inmostcasesthespherulesdisplayreactionrimsandcoronasofsubmicroscopicfinemineralassemblages.Thesespherulesarenot“secondaryvesiclefillings”,sincetheyaremadeupofveryfine-grainedtocryptocrystallinecarbonatewith“schlieren”andspinifextextures.

3) Planar microstructures in quartz and calcite (e.g.inTrepmann2008) Small fragmental quartz grains of up to 100 µm are very abundant in the fine-breccias, homogenous carbonaceous pebbles and spherules. In all cases, they show undulate extinction and Boehm lamellae, which are results of tecto-nic deformation. However, in some cases “planar fractures (PFs)” are also present. Real “planar deformation fea-tures (PDFs)” have not been found.

Carbonate chemistrySeveralpebbleswithrelativelyhomogeneousfine-grainedandfeatherycalcitegroundmasswereanalyzedwithXRFmethodtoobtaintheirbulkchemicalcomposition.ThemajorelementsshowarathermarlylimestonecompositionwithSiO

230-35

wt.%,CaO28-32wt.%,Al2O

35-6wt.%,K

2O0.6-0.7wt.%,TiO

20.35-0.45wt.%andalowMgO0.6-0.9wt.%.Thetraceelements

displayratherlowconcentrations:Rb25-35ppm,Sr35-65ppm,Ba130-400ppm,Nb5-6ppm,lowvaluesofLREE;Cr110-160ppm,Ni50-65ppmandZn40-50ppm.TheonlyunusualenrichmentexistsinYwith30-70ppm.Suchacompositionsupportsanoriginofthepebblesfrommarlylimestones,butdiffersdramaticallyfromthecompositionofcarbonatiticglobulesfromvolcanicdiatremesintheultra-alkalineProvincenorthofRome(Stoppa&Lupini1993).

ConclusionThepetrographicandchemicalevidenceofthecollectedfine-brecciasandpebblesleadstotheinterpretationofthemateri-alas“impactfallbackbrecciasandcarbonatitictectitesduetometeoriticimpact,althoughuptonownometeoritefrag-mentshavebeenfound.Accordingtothesizeofthecraterlakesthedimensionsofthemeteorite,whichmighthavesplitintotwofragments,shouldhavebeenabout10-30mbeforereachingthesurface.Thetemperatureandpressureoftheim-pactmayhavebeensufficienttodecomposeandmeltthelimestonesfollowedbyquenchingduringcoolinganddecompres-siontoformthecarbonatiticpebblesandspherules.

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Graup,G.1999:Carbonate-silicateliquidimmiscibilityuponimpactmelting:RiesCraterGermany.Meteoritics&PlanetaryScience,34,425-438.

Marinos,G.1962:Surdeuxvolcansembryonnairesdutypemare,présd’Almyros-Thessalie.BulletinGeologicalSocietyofGreece,5,1,108-114.

Marinos,G.,Anastopoulos, J.,Maratos,G.,Melidonis,N.&Andronopoulos,B. 1962:GeologicalMapofGreece1 : 50000,SheetAlmyros.InstituteforGeologyandSubsurfaceResearch,Athen.

Osinski,G.R.,Spray,J.G.&Grieve2008:Impactmeltinginsedimentarytargetrocks:Anassessment.In:Evans,K.R.,Horton,J.W. Jr.,King,D.T. Jr.&Morrow, J.R.eds.,TheSedimentaryRecordofMeteorite Impacts.GeologicalSocietyofAmericaSpecialPaper,437,1-8.

Stoppa, F. & Lupini, L. 1993:Mineralogy and petrology of the PolinoMonticellite Caleiocarbonatite (Central Italy).Mineralogyandpetrology,49,213-231.

Trepmann,C.A.2008:Shockeffectsinquartz:Compressionversussheardeformation–AnexamplefromtheRochechouartimpactstructure,France.EarthandPlanetaryScienceLetters,267,322-332.

2.13

Rheological mechanisms, topographic response, and geodynamic regimes associated with slab breakoff

DuretzThibault*&GeryaTaras*

*ETH Zürich, Institute of Geophysics, Sonnegstrasse 5, CH-8092 Zurich (thibault.duretz@erdw.ethz.ch)

Asetofnumericalexperimentswerecarriedouttostudytheeffectofslabbreakoffonasubduction-collisionsystem.Thenumericalcode I2VIS (Gerya&Yuen,2003)usedforthispurposeallowsactivationofplasticity,viscouscreepandPeierlscreep.

Atwo-dimensionalsystematicstudywasperformedbyvaryingtheoceanicslabageandinitialplateconvergencerate.Inthisparameterspace,fourdifferentend-memberswereobservedwherebreakoffdepthcanrangefrom40to400km.Differentcombinationsofrheologicalmechanismsleadtodifferentbreakoffmodes.ActivationofPeierlsmechanismgenerallyallowsslabstobreakfasterandshallower.

Eachbreakoffend-memberhasitsowntopographicsignalevolutionandalwaysdisplayasharpbreakoffsignal.Averagedpost-breakoffupliftratesrangesbetween0,8km/Myforshallowdetachmentand0,2km/Myfordeepdetachmentinforelandandhinterlandbasins.

Initiationofcontinentalcrustsubductionwasobservedwhenusinganoceaniclithosphereolderthan30My.Differentex-humationprocessessuchasslabretreatandeductionwereobserved.Largepost-breakoffreboundassociatedwithplatede-couplingoccursifthesubductedoceanicslabisoldenough.

REFERENCESGerya, T. V.& Yuen,D. A. 2003: Charaterictics-basedmarkermethodwith conservative finite-difference schemes for

modelinggeologicalflowswithstronglyvariabletransportproperties.PhysicsoftheEarthanPlanetaryInteriors140(4),293–318.

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New structural field data from SE of the Mont Blanc massif and prelimi-nary constraints on models of exhumation

DanielEgli*&NeilMancktelow*

* Geologisches Institut, ETH-Zürich, Sonneggstrasse 5, CH-8092 Zürich (daniel.egli@erdw.ethz.ch)

ThekinematicsoftheexhumationoftheMontBlancmassifisstillacontroversialtopicwithvariousmodelsproposed.MostinformationontheNeogeneexhumationhistoryofMontBlanccomesfromlow-temperaturethermochronologystudies(e.g.Seward&Mancktelow1994;Leloupetal.2005;Glotzbachetal.2008)andthereisstilllackofdetailedstructuraldata.ThisstudyprovidesnewdetailedinformationaboutthedeformationalhistoryandtheexhumationoftheMontBlancmassifanditsadjacentcover.WetrytoestimatetheimportanceofdextraltranspressionalmovementsduringtheupliftofMontBlancanditspossiblelinkwiththeSimplon-Rhonefaultzone,inordertochecka2Dpop-upmodelagainstamore3Ddextraltranspressivemodel,developingapositiveflowerstructure.Wepresentherepreliminaryresultsofthefirstfieldseason,whichincludeddetailedstructuralinvestigationsandstructuralmappingofthesouth-easternboundaryoftheMontBlancmassifintheSwissandItalianpartsofValFerret.Thestudyareaissituatedonthesouth-easternsideoftheMontBlancmassif.GeologicallyitcoverstheunitsoftheMontBlancmassif,theHelveticandUltrahelveticnappesandsedimentsofthelowerPenninicnappes.TheMontBlancmassifisoneoftheexternalcrystallinemassifs,whichrepresentthebasementoftheformerEuropeancontinentalmarginandthe-reforebelongstotheHelveticdomain. Itmainlyconsistsofpre-VariscanbasementandVariscangranitoids.Themassif isoverlainbytheMesozoictolowerTertiarysedimentsoftheHelveticsandUltrahelvetics.ThesewereoverriddenalongthePenninefrontalthrustbysedimentsofthenorthernPenninicoceanduringtheTertiaryAlpineorogeny.Thesediments,aswellasthecrystallinerocksoftheMontBlanc,sufferedapolyphasemetamorphicanddeformationalhistory.Wewereabletodistinguish4generationsoffoldsintheHelvetic,UltrahelveticandPenninicsedimentsoftheworkingarea.Theappearanceofthefoldscandifferwithchanginglithologies,butthemaincharacteristicsremainthesame.Wenumbe-redthemasregionalD1-D4.D1isonlyvisibleasapenetrativecleavage,S1,withsomerarerelicsofisoclinalfoldhinges.ItisfoldedbyD2,typicallyforminglong-limbedtighttoisoclinalfoldsandoftenaspacedcrenulationcleavage,S2.TheS2cleavageisthemainfoliationinmostpartsofthestudyareaandhasarelativelyconstantorientationdippingtowardthesouth-east.Thethirddeformationphaseisnotfoundeverywhereinthestudyarea.D3foldsformrathershort-limbedkinkytowavyfolds,oftenaccompaniedbyacrenulationlineationparalleltotheD3foldaxis.IfD3formsanaxialplanecleavage,itisquitespacedandsubverticalordippingtowardsthenorth-west.Thesestructurescouldrepresentabackfold-typestruc-ture.TheD4canmainlybefoundintheblackshalesbetweenGrandColdeFerretandFerretvillage.Theyhaveatypicalcollapse-typeappearance,withsubhorizontalaxialplanesandverykinkyhingesandlocallyresultinanorth-westwarddip-pingmainfoliation.AnimportantaspectoftheareaistheregionalchangeinorientationoftheboundarybetweentheMontBlancmassifandtheoverlyingsediments.IntheareaaroundthesoutheastportaloftheMontBlanctunnel(i.e.nearCourmayeur),thebase-mentoverliesthesediments,theoverturnedboundarydipsca.45°towardthenorth-east,andthecontactisoftendiscor-dant.Intheareasmoretothenorth,thedipchangesgraduallytoverticalandfinallydipssouth-east.ThebasementseemstobethrusteastwardsontothesedimentsintheCourmayeurarea,althoughnomajorthrustplanecouldbedetectedma-croscopically.IntheSwissValFerretthecontactisconcordantandmostprobablysedimentary.Onamesoscopicscale,weobservedthattheactualcontactbetweenthebasementandcovercannotbeaverylatestagestructurebecauseitisslightlyfoldedwithanewsteepfabricdevelopedinboththesedimentsandthegranite.Thisfoliationisweaklyrefractedacrosstheboundary.IntheslightlyhighermetamorphicrocksaroundPetitColdeFerret,smallenclavesofmarbleareductileyfoldedintothebasementrocks.CalciteslickenfibresarequitecommonintheHelveticandUltrahelveticsedimentsandhavevariousorientations.Themostdominantdirectionhasadextralstrike-slipsenseofmovementandplungesshallowlytowardNEorSW.Inthestronglyfoli-atedblackshales,thefaultplanesusuallycorrespondwiththemainfoliationwhereasinthemorecompetentlimestonestheymakeasmallangletothemainfoliationandgenerallycorrespondtoRiedel-typefaults.Morerarely,onecanfindsub-verticalslickenfibresshowingboththrustingtowardthenorth-westaswellaswest-side-upmovements.ThesearetheonlystructuresfoundwhosekinematicscouldbedirectlyrelatedtoexhumationoftheMontBlanc.Therelativeageofthediffe-rentbrittlemovementsisnotyetestablished.Althoughaneastward-directedbackthrustingofMontBlancbasementovercoversedimentsmayhaveoccurred,itcannotbethereasonforthelateNeogeneupliftbecausethecontactissubsequentlyductileydeformed.Amajorstrike-slipcomponentisfoundontheeasternboundaryofthemassifandthismovementcouldwellrepresentasouthwardcontinutionoftheRhone-Simplonline.However,suchtranspressivemovementsareprobablynotthereasonfortheupliftoftheMontBlanc,becausetheshallowlynorth-eastwardplungingfibresshowingadextralsensewouldratherhaveawest-side-downverticalcomponent.

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Glotzbach,C.,ReineckerJ.,Danisik, M.,Rahn,M.,Frisch,W.&C.Spiegel2008:NeogeneexhumationhistoryoftheMontBlancmassif,westernAlps,Tectonics,27.

Leloup,P.H.,Arnaud,N.,Sobel,E.R.&LacassinR.2005:Alpinethermalandstructuralevolutionofthehighestexternalcrystallinemassif:TheMont

Blanc,Tectonics,24.Seward,D&MancktelowN. S. 1994:Neogenekinematics of the central andwesternAlps: Evidence from fission-track

dating,Geology,22,803–806.

2.15

Reflection and scattering of Stoneley guided waves at the tips of fluid-filled fractures

FrehnerMarcel*andSchmalholzStefanM.**

* Department for Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria (marcel.frehner@univie.ac.at)** Geological Institute, ETH Zurich, Sonneggstrasse 5, 8092 Zurich, Switzerland

Understanding seismicwavepropagation in fractured fluid-rock systems is important for estimating, for example, fluidpropertiesorfracturedensitiesfromgeophysicalmeasurements.Stoneleyguidedwaveshavebeenused,forexample,toex-plainlong-periodvolcanictremorsignalsortoproposepotentialmethodsforestimatingfluidpropertiesinfracturedrocks.Inthisstudy,thefiniteelementmethodisusedtomodeltwo-dimensionalwavepropagationinarockwithafinitefluid-filledfracture(Figure1).Thesurroundingrockisfullyelasticwithnon-dispersivenon-attenuatingP-andS-waves.Thefluidfillingthefractureiselasticinitsbulkdeformationbehaviorbutviscousinitssheardeformationbehavior.Therefore,onlyP-wavescanpropagateinthefracture,whicharedispersiveandattenuated.Thefracturegeometryisresolvedindetailbytheappliedunstructuredfiniteelementmeshusingtriangles.AStoneleyguidedwaveisaspecialwavemodethatisboundtoandpropagatesalongthefracturewithamuchsmallerve-locitythanallotherwavesinthesystem.Inthisstudy,thewavelengthoftheStoneleyguidedwaveistwoordersofmagni-tudelargerthanthethicknessofthefracture.Itsamplitudedecreasesexponentiallyawayfromthefracture,whichmakestheStoneleyguidedwavedifficult todetectalreadyarelativelyshortdistancesawayfromthefracture.Atthetipof thefracturetheStoneleyguidedwaveisreflected(Figure1).Theamplituderatio|R|betweenreflectedandincidentStoneleyguidedwaveiscalculatedfromnumericalsimulations(Figure2),whichdependonthetypeoffluidfillingthefracture(wa-ter,oilorhydrocarbongas),thefracturegeometry(ellipticalorrectangular)andthepresenceofasmallgascapatthefrac-turetip.Foranellipticallyshapedfracture(aspectratioofellipse=333)theamplituderatiovariesbetween75%foroilandwaterandalmost100%forgas.Althoughthefracturethicknessistwoordersofmagnitudesmallerthanthewavelength,theshapeofthefracturetipinfluencesthisratiosignificantly.TheamplituderatioofaStoneleyguidedwaveatthetipofastraightwater-filledfracturewithaflatfracturetipisaround43%.ThepartoftheStoneleyguidedwavethatisnotreflectedisscatteredatthefracturetipandemittedintothesurroundingelasticrockaselasticbodywaves(Figure1).Forfullysaturatedfracturestheradiationoftheseelasticbodywavespointsineverydirectionsfromthefracturetip.Inthepresenceofasmallgas-capatthetipofafluid-filedfracturetheradiationoftheelasticbodywavesisstronglyforwarddirected.TherelativelystrongreflectionatthefracturetipenablestheStoneleyguidedwavetotravelbackandforthalongafractureseveraltimesbeforeitloosestoomuchofitsinitialenergy.Thisleadstoaperiodicradiationofbodywavesatthefracturetip.ThecorrespondingfrequencycanbelowinrelativelysmallfracturesduetothesmallvelocityofStoneleyguidedwaves.TheemittedelasticbodywavesmayallowdetectingStoneleyguidedwave-relatedsignalsatdistancesawayfromthefracturewheretheamplitudeoftheStoneleyguidedwaveitselfistoosmalltobedetected.

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Figure1:Snapshotsofthe2DdisplacementfieldofasimulationofaStoneleyguidedwavepropagatingalonganellipticalcrackfilled

withwater.Upperpanelsshowthehorizontalcomponentofthedisplacementfield.Lowerpanelsshowtheverticalcomponentofthedis-

placementfield.Panelsfromlefttorightrepresentprogressivepointsintime.TheStoneleyguidedwaveispartiallyreflectedatthecrack

tipandelasticP-andS-wavesareemittedfromthecracktipintothesurroundingrock.

Figure2:Absolutevalueoftheamplituderatio|R|betweenreflectedandincidentStoneleyguidedwaveofaStoneleyguidedwavethatis

reflectedatthetipofacrack.Rxiscalculatedfromthehorizontaldisplacement-timesignalsateightreceiversinsidethecrack.Ryiscal-

culatedfromtheverticaldisplacement-timesignalsatsixreceiversoutsidethecrack.Valueslabeled“viscousfluids,ellipticalcracktip”

arederivedfromsimulationsofanellipticalcrackfullysaturatedwiththecorrespondingviscousfluid.Valueslabeled“flatcracktip”are

derivedfromasimulationofarectangularcrackwithaflatcracktipfullysaturatedwithviscouswater.Valueslabeled“oilwithgascap,

ellipticalcracktip”arederivedfromasimulationofanellipticalcrackpartiallysaturatedwithviscousoilandhavingasmallgascapat

thecracktip.

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Exhumation of a metamorphic complex in a strike-slip setting: observa-tions from the Chugach Metamorphic Complex (CMC), southern Alaska

DetaGasser*,EmilieBruand*,KurtStüwe*

*Department of Earth Science, Universitätsplatz 2, A-8010 Graz, Austria (deta.gasser@uni-graz.at

The exhumation of metamorphic rocks to the surface of the Earth is a much discussed subject in modern geodynamics. Models involving channel flow, pure and simple shear extrusion and others have been postulated based on observations in the Central Himalayan Crystalline Complex or the eclogite complexes in the Alps. Most of these models focus on the vertical component in profile view, not considering horizontal movements in plan view.

TheCMCofSouthernAlaskaconsistsoflow-Phigh-TgneissesthatdevelopedduringtheEoceneinaCretaceousaccretionaryprism.Theyareexhumedfrom20-35kmdepthbetweenmajorcrustal-scaledextralshearzones(Fig.1).Lineationsaretypi-callyparalleltostrikeandsub-horizontal,indicatingthathorizontalmovementinplanviewisavitalpartoftheexhumati-onprocess.Inaddition,thecomplexhasaparticulartriangularshapeinplanview,indicatingthattheexhumationhistorymightnotbethesameallalongthecomplexbutmightbedifferentinpartsofdifferentwidthofthecomplex.

Inordertounderstandthenatureofthelow-Phigh-Tmetamorphisminaaccretionarysettinganditssubsequentexhuma-tionhistorywearecurrentlyworkingonaprojectcombiningextendedfieldwork,petrological,structuralandgeochrono-logicalmethods.Duringthesummers2008and2009wemappedsixkeyareascoveringthewholecomplexfromnorthtosouthandfromeasttowestinordertounderstandthestructuralandpetrologicalvariationsalloverthecomplex.Wefur-thermorecalculateddetailedpressureandtemperatureconditions thatoccurredduringmetamorphismin thedifferentpartsofthecomplex.Inordertobetterunderstandthetimingandtheratesatwhichheating,coolingandexhumationoc-curred,weapplyseveralgeochronologicalmethodssuchasU-Pbdatingofmonazitesandzircons,ArArandRbSrdatingofbiotiteandmuscoviteandzirconfissiontrackdatingtorocksfromdifferentpartsofthecomplex.

InthiscontributionwepresentanoverviewofthegeologyoftheCMC,resultsfromourfieldworkaswellasfirstgeochro-nologicalresults.

Fig.1Tectonicoverviewmapandcross-sectionofsouthernAlaska.Abbreviations:CMCChugachMetamorphicComplex,gTFtransition

fault,PZPamplonazone,KIZKayakIslandZone,DRZDangerousRiverZone,CSEChugachStEliasFault,CFContactFault,FFFairweather

Fault,BRFBorderRangesFault,DFDenaliFault.

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The Rezli fault zone: Field observations from a major oblique-slip fault in the Rawil depression, Western Switzerland

Deta Gasser*, Neil Mancktelow**

*Department of Earth Science, Universitätsplatz 2, A-8010 Graz, Austria (deta.gasser@uni-graz.at)**Geological Institute, ETH Zürich, CH-8092 Zürich, Switzerland (neil.mancktelow@erdw.ethz.ch)

InWesternSwitzerland,theplungeoffoldaxesandtheregionaldistributionofunitsintheHelveticnappesdefineabroaddepression,theRawildepression,betweenthecrystallinerocksoftheAiguillesRougemassiftotheSWandtheAarmassiftotheNE.Thesouthernpartofthisdepression,togetherwiththeRhoneValleytothesouth,belongstooneoftheseismi-callymostactiveregionsinSwitzerland.SeismogenicfaultsinterpretedfromearthquakefocalmechanismsstrikeENE-WSWtoWNW-ESE,withdominantdextralstrike-slipandminornormalcomponentsandepicentresatdepthsof<15km.Inordertounderstandthepost-nappe-stacking,brittlefaultinghistoryofthisarea,wecompiledfaultdatafromtheliteratureandexistingmapsandconducteddetailedfieldworkononeexceptionallywell-exposedfaultzone,theRezlifaultzone(RFZ).

Thecompilationofdatafromtheliteratureestablishesthat,inadditiontothrustsrelatedtonappestacking,theRawilde-pressioniscross-cutbyfoursetsofbrittlefaults:(1)SW-NEstrikingnormalfaultsthatstrikeparalleltotheregionalfoldaxistrend,(2)NW-SEstrikingnormalfaultsandjointsthatstrikeperpendiculartotheregionalfoldaxistrend,and(3)WNW-ESEstrikingnormalplusdextraloblique-slipfaultsaswellas(4)WSW-ENEstrikingnormalplusdextraloblique-slipfaultsthatbothstrikeobliquetotheregionalfoldaxistrend.Faultset1wasprobablyinitiatedduringsedimentationandreactivatedduringnappefoldingandstacking,whereastheotherfaultsetsformedafteremplacementoftheHelveticnappes.

TheRFZbelongstofaultset3andisashallowtomoderately-dipping(ca.30-60°)faultzonewithanoblique-slipdisplacementvector,combiningbothdextralandnormalcomponents.Itmusthaveformedinapproximatelythisorientation,becausethelocalorientationoffoldaxescorrespondstotheregionalone,asdoesthegenerallyverticalorientationofextensionaljointsandveinsassociatedwiththeregionalfaultset2.Thefaultzonehasamaximumhorizontaldextraloffsetcomponentofca.300mandamaximumverticalnormaloffsetcomponentofca.200m.

Thefaultzonecrosscutsfourdifferentlithologies:(1)limestone,(2)intercalatedmarlandlimestone,(3)marland(4)sands-tone,anditsinternalarchitecturestronglydependsonthelithologyinwhichitdeveloped.Inthelimestone,itconsistsofveins,stylolites,cataclasitesandcementedgouge,intheintercalatedmarlsandlimestonesofanastomosingshearzones,brittlefractures,veinsandfolds.Inthemarlsitconsistsofanastomosingshearzones,pressuresolutionseamsandveinsandinthesandstonesofcoarsebrecciaandveins.Later,straight,sharpfaultplanescross-cutallthesefeatures.Inalllithologies,commonveinsandcalcite-cementedfaultrocksindicatethestronginvolvementoffluidsduringfaulting.

AllthreeNeogenefaultsets(2-4)couldhavebeenactiveundertheactualstressfieldinferredfromthecurrentseismicity.Thisimpliesthatthesamemechanismsthatformedthesefaultzonesinthepastmaystillpersistatdepth.ThedetailedobservationsfromtheRezlifaultzonecanactasamodelforprocessesstilloccurringatdeeperlevelsinthisseismicallyactiveregion.

2.18

Influence of rheology and giant impactors on the terrestrial core formation

GolabekGregor*,GeryaTaras*,KausBoris*,ZietheRuth**,MollGian-Peider***&TackleyPaul*

*Institut für Geophysik, Sonneggstrasse 5, CH-8092 Zürich (gregor.golabek@erdw.ethz.ch)**ESA/ESTEC-SCI-SM, Keplerlaan 1, NL-2201 AZ Noordwijk***Institut für Computerwissenschaften, Universitätsstrasse 6, CH-8092 Zürich.

Knowledgeabouttheterrestrialcoreformationmechanismisstillverylimited.Severalcoreformationmodeshavebeenproposed:Thefracturingmodesuggeststhatacentralunmeltedregionisdisplacedbyadegreeonemodefromthecenter

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icsoftheaccretingbodyandisfragmentedduetothelargestressescreatedbyanoverlyingasymmetricironlayer(Stevenson,

1981).Incontrast,coreformationviairondiapirs(e.g.ZietheandSpohn,2007),whichcanbeformedbygiantimpacts(e.g.Ricardetal,2009),havebeenproposed.Weinvestigatewhichcoreformationmodeisactiveundercertainconditions.Thereforeweperform2DsimulationsusingthecodeI2ELVISapplyingthenewlydeveloped“spherical-Cartesian”methodo-logy(GeryaandYuen,2007).ItcombinesfinitedifferencesonafullystaggeredrectangularEuleriangridandLagrangianmarker-in-celltechniqueforsolvingmomentum,continuityandtemperatureequationsaswellasthePoissonequationforgravitypotentialinaself-gravitatingplanetarybody.Inthemodel,theplanetarybodyissurroundedbyalowviscositymass-lessfluid(“stickyair”)tosimulateafreesurface.Weapplyatemperature-andstress-dependentviscoplasticrheologyinsideMars-toEarth-sizedbodiesandincludeheatreleaseduetoradioactivedecay,shearandadiabaticheating.Asinitialconditi-onweusestochasticallydistributedirondiapirswithrandomsizesintherangeof50to100kmradiusinsidetheaccretingplanet,representingtheirondeliveredbypre-differentiatedimpactors.Additionally,weaddagiantimpactorcoreintoseveralmodels.Forsimplicity,weneglecttheheatingoftheplanetarybodybytheimpactitself.Weassumetheimpactorcoretobeatrestatthebeginningofthesimulation.Asystematicinvestigationoftheinfluenceofsilicaterheology,temperatureanddiapirradiiondifferent-sizedprotoplanetsisbeingperformed.Weshowthatdependingonthesilicaterheology,whichisstronglydependentonthewatercontentofolivine(KatayamaandKarato,2008)andtheinitialtemperatureprofile,plasticyieldingandshearlocalizationtakeplaceanddifferentregimesofcoreformationappear:Forweakplanetaryinteriorsirondiapirssinkincollectivegroups,similartoalreadypublishedcoreformationmodels (e.g.ZietheandSpohn,2007).Forhighlyviscousplanetsanasymmetricironlayerforms,whichsurroundsthecentralpartoftheplanetoramixtureofdiapirismandfracturingmechanismdevelops.ResultsincludinglargediapirsindicatethatforMars-sizedandlargerbodiesarunawaydifferentiationprocesscanbeindu-ced.Wederivescalinglaws,whichpredicttheonsetofplasticyieldingandshearlocalizationinthesilicatesandoftheru-nawaydifferentiationprocessandtheassociatedcoreformationmodes.Thefinaltemperatureprofilesofthedifferentcoreformationmodesarediscussedwithregardtotheirinfluenceontheonsetofmantleconvection.

REFERENCESGerya, T.V.& Yuen,D.A. 2007: Robust characteristicsmethod formodellingmultiphase visco-elasto-plastic thermo-

mechanicalproblems.Phys.EarthPlanetInt.,163,83-105.Katayama, I.&Karato, S.-i., 2008: Low-temperature,high-stressdeformationofolivineunderwater-saturated conditions.

Phys.EarthPlanet.Int.,168,125–133.Ricard,Y.,Šrámek,O.&Dubuffet,F.2009:Amultiphasemodelofrunawaycore-mantlesegregationinplanetaryembryos.

EarthPlanet.Sci.Lett.,284,144-150.Stevenson,D.J.1981:ModelsoftheEarth’score.Science,214,611-619.Ziethe,R.&Spohn,T.2007:Two-dimensionalstokesflowaroundaheatedcylinder:Apossibleapplicationfordiapirsinthe

mantle.J.Geophys.Res.,112,B09403.

2.19

Towards self-consistent modelling of the Martian dichotomy: Coupled models of simultaneous core and crust formation

GolabekGregor*,KellerTobias*,GeryaTaras*&ConnollyJames**

*Institut für Geophysik, Sonneggstrasse 5, CH-8092 Zürich (gregor.golabek@erdw.ethz.ch)**Institut für Mineralogie und Petrologie, Clausiusstrasse 25, CH-8092 Zürich

OneofthemoststrikingsurfacefeaturesonMarsisthecrustaldichotomy,alargedifferenceinelevationandcrustalthick-nessbetweenthesouthernhighlandsandthenorthernlowlands.ThedichotomyisamongtheoldestgeologicalfeaturesonMarsandwasformedmorethan4.1Gaago(Solomonetal.,2005)owingtoeitherexogenicorendogenicprocesses(e.g.KellerandTackley,2009). Inordertofindaninternaloriginofthecrustaldichotomy,locatedwithinamaximumof400Maofplanetarydifferentiation,thethermalstateoftheplanetresultingfromcoreformationneedstobeconsidered.BasedonthegeochemicalanalysisofSNCmeteorites itwas suggested thataprimordial crustwithup to45kmthicknesscanbeformedalreadyduringtheMartiancoreformation(Norman,1999).Thereforewesuggestthatthesinkingofirondiapirsdeliveredbypre-differentiated impactors inducedshearheating-relatedtemperatureanomalies inthemantle,whichfos-teredtheformationofearlyMartiancrust.Inthisstudy,weexamineparametersetsthatwilllikelycauseanonsetofhemi-sphericallow-degreemantleconvectiondirectlyafter,andcoupledto,analreadyhemisphericallyasymmetricalcoreforma-tion.Totestthishypothesisweuseanumericalmodel,whereweself-consistentlycoupletheformationoftheMartianiron

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s coretotheonsetofmantleconvection.Peridotitemeltingisenabledtotrackmeltingandcrustformationcausedbyheatreleasedfromcoreformationandradioactiveheating.We perform 2D simulations using the code I2ELVIS applying the recently developed “spherical-Cartesian”methodology(GeryaandYuen,2007).ItcombinesfinitedifferencesonafullystaggeredrectangularEuleriangridwithLagrangianmarker-in-celltechniquetosolvemomentum,continuityandtemperatureequationsaswellasthePoissonequa-tionforgravitypotentialinaself-gravitatingplanetarybody.Inourmodelsetup,theplanetissurroundedbyalowviscosity,masslessfluid(“stickyair”)tosimulateafreesurface.Weapplyatemperature-andstress-dependentviscoplasticrheologyinsideaMars-sizedplanet.Radioactiveandshear-heatingaswellasconsumptionoflatentheatbysilicatemeltingaretakenintoaccount.Thedepthofneutralbuoyancyofsilicatemeltwithrespecttosolidsilicatesisdeterminedbythedifferenceincompressibilityoftheliquidandsolidphase.Toself-consistentlysimulatethesilicatephasechangesexpectedinsideaMars-sizedbody,weemploythethermodynamicalPerple_Xdatabase (Connolly,2005).As initialcondition,weapplyrandomlydistributedirondiapirswith75kmradiusinsidetheplanet,representingthecoresofstochasticallydistributedimpactorscharacteristicforthelateaccretionstageofterrestrialplanets.Additionally,weexploretheeffectofonegiantimpactorcoreontheplanetaryevolution.Results indicate that the presence of a large impactor core induces hemispherically asymmetrical core formation.Furthermore,theamplitudeofshearheatinganomaliesgenerallywellexceedsthesolidusofprimitivemantlematerial.Theformationofaconsiderableamountofsilicatemeltisobserved.Someofthegeneratedmeltsegregatestothesurfacetoformprimordialcrust,whereasnegativelybuoyantmeltfromdeepersourcessinkstotheCMB.Thehemisphericalasymmetryintemperatureinducedbyagiantimpactorworksinfavourofanonsetoflow-degreemantleconvectionaftercoreformation.Suchahemisphericalconvectiongeometrymightsubsequentlybesustainedbyphase-dependentviscosity(KellerandTackley,2009),andthusharbouranearlydevelopmentofadichotomouscrustalthicknessdistribution.

REFERENCESConnolly, J.A.D.2005:Computationofphaseequilibriaby linearprogramming:A tool forgeodynamicmodelingand its

applicationtosubductionzonedecarbonation.EarthPlanet.Sci.Lett.,236,524–541.Gerya, T.V.& Yuen,D.A. 2007: Robust characteristicsmethod formodellingmultiphase visco-elasto-plastic thermo-

mechanicalproblems.Phys.EarthPlanetInt.,163,83-105.Keller, T. & Tackley, P.J. 2009: Towards self-consistent modelling of the Martian dichotomy: The influence of one-ridge

convection on crustal thickness distribution. Icarus, 202, 429–443.Norman, M.D. 1999: The composition and thickness of the crust of Mars estimated from rare Earth elements and

neodymium-isotopic compositions of Martian meteorites. Meteorit. Planet. Sci., 34, 439–449.Solomon S.C., Aharonson, O., Aurnou J.M., Banerdt W.B., Carr M.H., et al. 2005 : New perspectives on ancient Mars.

Science, 307,1214–20.

2.20

Integrated U/Pb, (U-Th)/He and oxygen stable isotope study on zircon of a normal fault zone of the western Alps, Switzerland

I.Guerra*,D.Stockli**,F.Corfu***,F.Negro****,N.Mancktelow*****andT.Vennemann*

*Institut de Minéralogie et Géochimie, Université de Lausanne, Anthropole, CH-1015 Lausanne, Switzerland (ivan.guerra@unil.ch) **Department of Geology, University of Kansas, 1475 Jayhawk Boulevard, Lawrence KS 66045-7613, USA***Department of Geosciences, University of Oslo, Sem Sælands vei 1 Blindern, 0316 Oslo, Norway****Centre d’Hydrogéologie et Géothermie, Université de Neuchâtel, Emile-Argand 11, CH-2009 Neuchâtel, Switzerland*****Geologisches Institut, ETH Zürich, Sonneggstrasse 5, CH-8092 Zürich, Switzerland

Small,euhedralzircons(upto80µminlength)werefoundinlatehematite-andquartz-richveinsoftheArollaarea(westernAlps,Switzerland), crosscutting twodifferent typesofAlpineunits: theDentBlancheKlippeandtheTsatéNappe.Thesezircons–togetherwithzirconsintherelativehostrocks–havebeeninvestigatedfortheirU/Pb,(U-Th)/He,andoxygeniso-topecompositionsinordertodeterminethethermalhistoryofthisportionoftheAlpsviathecoolingpathoftheseminer-als.

U/Pbanalysisindicatesthatthezircons–bothinthelateveinsandinthehostrock-haveabsoluteradiometricagescluste-ringaround270-280Ma,whichistheacceptedageforintrusiverocksfromtheAustroalpineDentBlancheunitsbutwhichisinapparentcontrastwiththeinterpretationoftheTsatéNappeasanophioliticremnantoftheJurassicLiguro-PiemontaisOcean.TheotherconclusionoftheseU/Pbanalysesisthatthezirconsinthelateveinsareallinheritedfromthehostrock.

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Thesamesampleswereinvestigatedwiththe(U-Th)/Hemethod.Firstresultsindicatethatthecoolingagesforthehostrocksaredifferentcomparedtothecoolingagesforthezirconsinlateveins:inparticularthecalculatedcoolingagefortheArollagneissis25.5±2.0Ma,whilethecoolingagefortheassociatedmineralizedfaultplaneis17.7±1.4Ma.ThecoolingagesfortheTsatémetagabbroclusteraround30Mawithoneimportantexceptionat311.8±36.9Mathatneedstobefurtherinve-stigated.

Oxygenstable isotope fractionationsbetweenquartzandhematite in the same lateveinscorrespond to temperaturesofabout170°C.Theproximityofthecalculatedemplacementtemperatureforlateveinsandtheloweracceptedclosuretem-peratureforzirconinthe(U-Th)/Hesystem(~180°C,Reinersetal.,2004)implythattheageof17.7±1.4Macanbeinterpretedastheformationageofthislatebrittlefracture.

Furtheranalysesonthetwounitsareinprogressandfocusontwomaindirections:1)analysisofothermineralizednormalfaultplanestocomparetheircoolingagewiththecoolingageoftheirrespectivehostrock,and2)coolingagedetermina-tionsonthehostrockstobetterunderstandtheregionalthermalpathofthisportionoftheAlps,whichissofarpoorlyunderstood.

REFERENCESReiners, P.W., Spell, t. L.,Nicolescu, S. andZanetti,K.A. (2004): Zircon (U-Th)/He thermochronometry:Hediffusionand

comparisonswith40Ar/39Ardating.Geochim.Cosmochim.Acta68,1857-1887.

2.21

Quaternary fluvial patterns on the in-land Makran accretionary wedge (SE IRAN)

HaghipourNegar*,**,BurgJean-Pierre*,KoberFlorian*&ZeilingerGerold***

*Geological Institute, ETH Zurich, Sonneggstrasse 5, CH-8092 Zurich (negar.haghipour@erdw.ethz.ch)**Geological Survey of Iran, Meraj Avenue, Azadi Square, P.O. Box 13185-1494,Tehran, Iran***Institute für Geowissenschaften, Universität Postdam, D-14476 Golm, Deutschland

WedocumentthefivemostimportantdrainagebasinsoftheIranianMakranandtheirfluvialterracestoinvestigatethesurfacerecordoftheon-goingMakransubductionzone.Wecomparestreamprofilesextractedfrom30mresolutionDEM-Asterimagesusingaslope-areamodelforthemainchannelofeachcatchment.Thefivestudiedriversaretransverseandflowfromthenortherncrestlineoftheaccretionarywedgetothecoastalplain,inthesouth.Thestream-profilesshowaconvex-uppatternthatsuggestsdisequilibriuminthewesternandeasternpartsofthesubductionzone,inIran;thisisincontrastwiththecentralpart,whereoneriverhastheconcave-upprofileexpectedfromanequilibriumstate.Theknick-zonesalongallriverprofilescoincidewithmajorfaultsandfoldsratherthanlitholo-gicalchanges.Theresultsfromslope-areadata,steepnessindex(Ks)andconcavityindex(θ)suggestaspatiallyvariablesurfaceuplift.Thesouthwarddivergenceoftheprojectedstrathterracesof2oftheseriversfurtherindicatesdifferentialbedrockupliftinthesouthcomparedtothemorehomogeneousnortherninnerMakran.Fieldmappingofthefluvialterraces,complementedbyinformationfromaerialphotos,topographicmapsandheightcor-relation,reveals5regionalterracelevels.Temporalcorrelationofthesefivelevels,usingterrestrialcosmogenicnuclides(TCN)datingmethod,isinprogress.Thistimeinformationwillconstrainthereconstructionofthepaleo-valleysofthestudiedriversandwillprovideaframeforpreciseestimatesofthesurfaceupliftrate,incisionrateandthetectonicsignificanceofverticalsurfacemovementsonaccretionarywedges.

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Strain localization in quartz mylonites of the Simplon Fault, Central Alps

HärtelMike*&HerweghMarco*

*Institut for Geoscience, University of Bern, Baltzerstrasse 1+3

TheSimplonFaultzone(SFZ)isamajordetachmentfaultbetweentheUpperandLowerPenninicUnitsintheCentralAlpsandcomprisesmyloniticmicrostructuresdeformedunderthepresenceofwater(Mancktelow&Pennacchioni2004andre-ferencestherein)atmetamorphicconditionsrangingfromlowergreenschistfacies(N)toupperamphibolitefaciescondi-tions inawater richenvironment (S). Inorder to study strain localizationhistory in this large-scale structure,differentsampleserieswerecollectedalongprofilesacrosstheSimplonfaulttoinvestigatethechangesindynamicrecrystallizationmechanisms,couplingofquartzgrainsize,presenceofsecondphasesandcrystallographicpreferredorientation(CPO).Inthecaseofpurequartzmylonites(formerqtzveinsandqtzlenses),ribbongrainsoccurwithina900meterwidehighstrainzone.Therecrystallizedgrainsizeinthisfaultzonegenerallyisreducedcomparedtotheundeformedveins,butthedegreeofgrainsizereductionvariesstrongly.Intermsofdynamicrecrystallization,thesmallestgrainsizescorrelatewithbulgingrecrystallizationandsubgrainrotationrecrystallization.However,alsocombinationsofgrainboundarymigrationrecrystal-lizationeitherwithbulgingnucleationorsubgrainrotationoccur.Insuchmicrofabrics,themeanrecrystallizedgrainsizeisrelativelylarge.Interestingly,thesegrainsizechangesarenotsystematicallyasafunctionofdistancetothefaultcontactbutratheroccurinformofdifferentdomains.IntermsofCPO,astrengtheningisobservedtowardsthecontactexceptatthecontactitself,weretheoccurrenceofcataclasitesinducedaCPOweakening.Basedontheseobservations,andpreviousstudiesofHirth&Tullis(1992)andStippetal.(2002),wesuggestthattheobservedchangesingrainsizeandrecrystallizationmechanismarerelatedtoacooling-inducedstrainlocalizationduringprogressivedeformation.Thefactthathightempera-turemicrostructuresarejuxtaposedtolowtemperaturemicrostructuresindicatesanoverprintoftheoldhigh-temperaturedeformationhistoryunderlowertemperatureconditions.Interestingly,thislaterstrainlocalizationdidnotresultinasym-metric strain localizationpattern in the large-scale shear zonebut rather shows local variations, eventuallypointing toepisodicchangesinthespatialdistributionofdeformationduringtheevolutionoftheSimplonfault.

REFERENCESHirth,G.andTullis,J.,1992:Dislocationcreepregimesinquartzaggregates.J.Struct.Geol.,14(2):145-159.Mancktelow,N.S. andPennacchioni,G., 2004: The influenceof grainboundary fluidson themicrostructureofquartz-

feldsparmylonites.JournalofStructuralGeology,26(1):47-69.Stipp,M., Stünitz,H.,Heilbronner,R. andSchmid, S.M., 2002:Dynamic recrystallizationofquartz: correlationbetween

natural and experimental conditions. In: S. deMeer,M.R. Drury, J.H.P. de Bresser andG.M. Pennock (Editors),DeformationMechanisms, Rheology and Tectonics: Current Status and Future Perspectives. Special Publications.GeologicalSociety,London,pp.171-190.

2.23

Petrography and geochemistry of upper mantle and lower crust of supra-subduction (?) ophiolites in the Makran, SE Iran

HunzikerDaniela*,BurgJean-Pierre*,BouilholPierre**,JafarOmrani***

*Geological Institute, Structural Geology and Tectonics, ETH Zurich, Sonneggstrasse 5, NO E69, CH-8092 Zurich (daniela.hunziker@erdw.ethz.ch)**Department of Earth, Atmospheric and Planetary Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue Cambridge, MA02139, USA***Geological Survey of Iran, Meraj Avenue, Azadi Square, P.O.Box 13185-1494, Tehran, Iran

Ophiolites archive tectonic and chemical processes in oceanic lithosphere from its crystallization to accretionary stagesduringobductionand/orcontinentalcollision.Theoriginofophiolitesissubjecttodiscusssincetheycanevolveinvariousgeotectonicsettingswhosediscriminationischallenging.Despite excellent outcrop conditions and exposure of a complete sequence, the Remeshk/Mokhtaramabad and Fannuj/MaskutanophioliticcomplexesintheSoutheastIranianMakranareahavebeenveryscarcelysurveyed.TheseophiolitesaresituatedalongthenorthernboundaryoftheinnerMakranaccretionarywedge,abovetheactivesubductionoftheArabianplatebeneath theEurasia.Wepresent first resultsonstructures,petrography,geochemistryandgeochronologyof theseophiolites.Theultimategoalistoreconstructtheiroriginalgeotectonicsetting,themagmaticprocessesthatproducedthemandthetectonicevolutionofthearea.

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icsTemporalandstructuralrelationsbetweenthedifferentlithologieshavebeenestablishedanddetailedcrosssectionsillus-

trateourpreliminarymap,muchmoreprecisethanpreviousones.Theextensiveultramaficcomplexescomprisealower,harzburgite-dominatedunitwithfewlherzolitesoverlainbydunites.Pyroxene-bearingperidotitesshowtypicalfeaturesoftectonizedmantledeformedatsub-solidusconditions.Theolivinechemistry(xMg=0.90-0.91,NiOcontentof0.4-0.45wt%)indicatesthattheyrepresentophioliticuppermantle.MostdunitesarecharacterizedbycumulatetexturesinolivineandaslightlylowerxMg=0.88-0.89andNiOcontentof0.27-0.35wt%.Dunitesarelocallyimpregnatedbyplagioclase-richmeltswithminor amounts of clinopyroxene and intruded bymany gabbroic dykes,whichmark the transition zone betweenmantleandcrust.Thegabbroicsequenceabovethedunitesdisplaysincreasinglydifferentiatedrocksoriginatedfromthesamemagmasource,upwardinthefollowingorder:troctolite-olivinegabbro–gabbro-anorthositicdykes-diabase.Theserocksarelaterintru-dedbyplagiogranitesandhornblende-gabbroswhoseassociationwiththeophiolitesisnotclarified.BulkrockandmineralcompositionsshowoceanicfeaturesofafastspreadingMOR,butsomeindicatecrystallizationinasupra-subductionrealm.TraceelementanalysesandgeochronologywillconstraintheevolutionoftheMakranophiolites.

2.24

Brittle deformation bands in the sandstones of the Western Swiss Molasse Basin

Ibele,Tobias*,Matzenauer,Eva*,Mosar,Jon*

*Départment de Géosciences Université de Fribourg, Chemin du Musée 6, CH-1700 Fribourg (tobias.ibele@unifr.ch)

Brittledeformationinporoussandstonewasdescribedtotakeplaceascataclasisonagrainsizescale,formingdeformationbands(DB)(Aydin1978).Thesebrittledeformationbandstypicallyareafewmmwidezonesofreducedporosityasaresultofreducedgrainsizesbyfracturing.Thedenserpackingoftheangularsubgrainsleadstostrainhardeningandsubsequent-lyongoingdeformationcreatesnewDBssub-paralleltotheinitialones.Increasingstrainiscompensatedbyseveralanasta-mosingDBsformingdeformationbandshearzones(DBSZ)whichareuptoseveraltensofcentimetreswideandoftenendupwithadiscreteslipsurface (Aydin&Johnson1978).TheprocessofformingbrittleDBswasdescribedtotakeplaceinporoussandstonesoftheupperfewkmofthecrustaswellasinunconsolidatedclasticsedimentsnearthesurface(Cashman&Cashman2000).

InourstudyDBsturnedouttobeaprominenttectonicstructureintheWesternSwissMolassebasinthattogetherwithslickensidesinfaultzonestakeupaconsiderableamountofdeformation.Althoughtheyarehithertoundescribedfromthearea,theyareabundantinthesandstonesoftheLowerFreshwaterandUpperMarineMolasse(USMandOMM).Duringstruc-turalfieldworkwefrequentlyfoundsingleDBs,largeDBSZswithandwithoutslip-planesandnetworksofDBSZsthatin-tersectandoffseteachotherindicatingsuccessiveevents.Investigationofthinsectionsshowedtypicalzonesoffracturedgrainsaswellasveryfinefaultgaugeswithapoorlyevolvedfoliation.SomeoftheDBsarefoundtobecementedbycalcitebutmostofthemareformedbyunconsolidatedfaultgauges,whichissuggestivetoarelativelowdepthand/orrecenttimeoftheirformation.InonecaseasynkinematicleygrownwhitemicaassociatedwithaSCstructurewasfoundtofillthecoreofaDB,pointingtowardsspecialconditionsduringdeforma-tionincludingfluidsandprobablyacertainburialdepth.Furthermoresuchwhitemicaofferstheopportunityofquantita-tivedatingbutfeasibilityisstillunclearinourcase.

WithinnetworksofDBSZsomeofthecrosscuttingrelationshipsaresystematicwithrespecttoorientationbutarenotsyste-maticwithrespectivechronologytotimesequence,indicatingacontemporaneousevolutionasRiedelsystems.Theorienta-tionandkinematicsofthemappedDBscorrelateswellwiththeoneselaboratedfromslickensidesinthestudyareaastheyareright-lateralwhenstrikingWNW-ESEandleft-lateralwhenstrikingN-S.TheydeforminastrikeslipregimewithNW-SEcompressionthatstartedintheupperMioceneandpersistsuntilrecenttimes.

REFERENCESAydin,A.1978:Smallfaultsformedasdeformationbandsinsandstone,PureandAppliedGeophysics116,913-930.Aydin,A.&Johnson,A.M.1978:Developmentoffaultsaszonesofdeformationbandsandasslipsurfacesinsandstone,Pure

andAppliedGeophysics116,931-942.Cashman, S.&Cashman,K. 2000:Cataclasis anddeformation-band formation inunconsolidatedmarine terrace sand,

HumboldtCounty,California,Geology28,2,111-114.

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Lateral fold identification in Northern Tunisia Thrust Belt front

*AridhiKais,**MohamedAbdoullahOuldBagga,*SaâdiAbdeljaouad,*FouadZargouniand***EricMercier

*Faculty of Sciences of Tunisia, Department of Geology, 2092 Tunis-El Manar I -Tunisia (Aridhikais@Gmail.com).** Faculty of Sciences of Gabès, Department of earth sciences, City Riadh Zrig-1030 - Gabès -Tunisia.*** Science and Technical Faculty of Nantes - France.

Tectonictransportofsedimentarysequencesledtotheirdeformationinfault-related-foldsknowninthetectonicstyleas"rampfolds".Someofthesefoldscalledfrontalrampfolds,striketransversallytothethrusttransport,whereasthelateralfolds,developparalleltothisdirection.However,thepresenceoffoldaxisorientedatahighanglewithrespecttothetrans-portdirectionmayreflectvariousdeformationkinematicsandmechanisms,ashighlightedbyWilkersonetal.(2002)andFrizondeLamotteetal.,(1995).IntheTunisianthrustandfoldbelt,(fig.1)thefaultrelatedfoldswererecognizedonlyinarecentdate,OueldBaggaetal.,(2006).Andthefoldstructureswereallinterpretedasfrontalfolds.Inthisworkwewillevidencebymeanoftwofieldexa-mples,thepresenceoflateralfoldsandwewilldiscussthegeometricalfeaturessuggestingtheirformationkinematics.ThefirstexampleisilustratedbytheAïnelBeystructure,whichbelongtotheexternaledgeofthenorthernTunisianbelt;thesecondexampleconcernsalocalstructureintheNumidianthrustsheet(fig.2-3).Inthissetting,wewillshowthatthesefoldorientationswithrespecttothetransportdirection,theirlimbdipvariation,thethrustfaultmigration,theexistenceofbedcut-offaswellassedimentarycriteria,suggestallthatthesefoldsarerelatedtopre-existingsynsedimentaryfaultsthatwerereactivatedduringthetectonicinversionaslateralrampfaults.Wewillaswellshowthatthepreviousstructuralandsedimentarydataarenotsuitablewithlateral foldformationasaconsequenceofsuperimposedtectonicstrain,oradrugalongstrikefaultsoradecreaseoftheslipmagnitudealongthefrontalfaults.

Fig.1:Alpinegeologybelt(DurandDELGA,1980)andareaofstudylocalization(extractedtogeo-logicalmapofTunisia1/500000),modified

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Fig.2:transverseandlongitudinalSectiononthelevelofAinElBeystruc-

Fig.3:sectionsintheNumidianthrustsheet

REFERENCEM.ScottWilkerson,TedApotriaandTammerFarid,(2002):Interpretingthegeologicmapexpressionofcontractionalfault

relatedfoldterminations:lateral/obliquerampsversusdisplacementgradients.Journalofstructuralgeology,2002,vol.24,no4,pp.593-607.

Frizonde Lamotte and JEAN-CLAUDEGUEZOU, (1995):Distinguishing lateral folds in thrust-systems; examples fromCorbihres(SWFrance)andBeticCordilleras(SESpain).JournalofStructuralGeology,1995,Vol.17,No.2,pp.233to244.

MohamedAbdoullahOuldBagga,SaâdiAbdeljaouadandEricMercier,(2006):La«zonedesnappes»deTunisie:unemargeméso-cénozoïque enblocs basculésmodérément inversée (régionde Taberka/Jendouba ; Tunisienord-occidentale),BulletindelaSociétéGéologiquedeFrance;May2006;v.177;no.3;p.145-154.

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Insights in the dynamics of free subduction from semi-analytical and numerical models.

KausBorisJ.P.*,**,Becker,ThorstenW.

*Geophysical Fluid Dynamics, Department of Earth Sciences, Schaffmattstrasse 30, CH-8093 Zurich (boris.kaus@erdw.ethz.ch)**University of Southern California, Los Angeles, USA.

Subductionzonedynamicshasbeenextensivelystudiedwithlaboratorymodelsinwhichadense,highviscosityslabsinksintoalessdenseandlessviscousmantle.

Recently,itwasfoundthattheselaboratoryresultscouldbereproducedwithnumericalmodelsiftheupperboundarycon-ditionisatruefreesurface,orifaweak‘sticky-air’layerisemployed[Schmelingetal,2008].

Yet,ourinsightinthedynamicsofsubductionremainssomewhatlimitedandnoscalinglawexiststhatpredictsslabveloci-ty(orslabbehavior)asafunctionofslabthickness,slab/mantleviscosityratioandslab/mantledensitydifference.Existingscalinglaws,suchastheapproachofConradandHager[1999,JGR],relyonknowingtheradiusofcurvatureofsubductingslabs,whichisaparameterthatistypicallyknownonlyafteranexperimenthasbeenperformed.

Forthisreason,wehereperformadditional2Dnumericalsimulationsinwhichweaddresstheeffectsofnumerics(resolu-tion,timestep),initialgeometry(slabtiplengthandangle),andrheologyonsubductiondynamicsinthepresenceofafreesurface.

Resultsconfirmearlierfindingsthatslabdynamicsistoalargeextendcontrolledbytheeffectiveviscositycontrastbetweenslabandmantle.Twomaindeformationmodesexistasafunctionofviscositycontrast:the‘drip’or‘Rayleigh-Taylor’modeoccursforviscositycontrastssmallerthanabout100,andisdominatedbyslab-stretchingandnon-constanthorizontalplatevelocities(whicharesignificantlylargertowardsthetrench).The‘plate’mode,ontheotherhand,occursforviscositycon-trastslargerthan500andischaracterizedbyslabsthatdonotchangetheirinitiallengthduringsubduction.Horizontalplatevelocitiesarehomogeneousalongtheslabtopandbendingoccursinthetrencharea,withabendingradiusthatde-pendsonviscositycontrastandslabthickness.Intheplatemode,theinitialslabtiplengthandanglehaveasignificantef-fectontheinitialsubductionrate.Aftertheslabtipreachedadepthofseveralhundredsofkm,however,subductionvelo-citiesarelargelyindependentontheinitialgeometryandaredescribedbyamodifiedStokeslaw.

Wedevelopedasemi-analyticalsubductionmodelbycombiningthisvelocityparameterizationwiththinviscoussheetequa-tions.Itisdemonstratedthatgoodagreementexistsbetweennumericalandanalyticalmodels,bothintermsofgeometryandintermsoftemporalevolution.

Inanextstep,theanalyticalmodelwasemployedtoderivescalinglawsforslabradius,whichscalesas1/3totheviscositycontrast,butisnearlylinearlydependentonslabthickness.Aconsequenceofthisisthatslab-dissipationisnomorethenabout25percentofthedissipationinthemantle.Moreover,itcanbedemonstratedthatstretchingdominatesslabbendingforslab-mantleviscositycontrastsoflessthanabout100(withaweakdependenceofslabthickness),inagreementwiththenumericalsimulations.

Thesemi-analyticalresultsareusedtoderiveaphasediagramforslab-dynamicsonEarth,whichpredictsseveralsubductionmodestoexist,ifaviscosityincreaseatthe660kmphasetransitionispresent,inagreementwithpreliminarynumericalsimulations.

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Numerical models of fluid migration in a tectonically active continental crust

KellerTobias,KausBorisJ.P.

Institute of Geophysics, ETH Zürich, Sonneggstr. 5, CH-8092 Zürich (keller@erdw.ethz.ch)

TheflowofalowviscosityfluidthroughtheporespaceofarigidmatrixisdescribedbyDarcy’slaw,statingthattheDarcyfluxq

Disgivenby

qD = Φ*(v

f - v

s) = - kΦ/η

f * ∇P

ex

,whereΦistheporosityoftherigidmatrix,vfandv

sthefluidandsolidvelocities,kΦ thepermeabilityofthematrix,η

fthe

dynamicfluidviscosityand∇Pexthegradientoftheexcessfluidpressure(fluidpressureexceedinghydrostaticpressure).

Weinvestigatethebehaviourofatwophase-systeminvolvingpartialmeltpercolatingthroughacontinentalcrust,whichitselfisbeingdeformedaccordingtoviscoelastoplasticincompressibleStokesflow.Todoso,weassumethatthefluidpres-sureisequaltothesolidpressureandthereforewecantake∇P

ex=∇P

sol-ρ

fg.Thesolidcompactiontermusuallypresentin

coupledStokes-Darcyproblemsisneglectedhere,sincethecompactionlengthscaleforparametersrelevanttoourproblemisontheorderof0.1-1km,whichisbelowournumericalresolution.

Thenumericalsetupinvolvesacontinentalcrustof20-30kmthicknessoverlyingthemantlelithosphere.Atthelithosphere-asthenosphereboundary,weintroduceasourceregionofpartialmelt,eithercylindricaloruniformlydistributed.Thesub-sequentpercolationofmelt through the crust is computeddependingas a functionofdynamicpressurewhichevolveswhilethecrustistectonicallydeformedineitherextensionalorcompressionalregime.

Firstresultsindicatethatboththegeometryandspatialevolutionofhighporositychannelsarestronglyrelatedtotheregi-onalstressfield.Weobserveverticalchannelsforextensionaltectonicsandhorizontalonesincompressionalenvironments.Additionally,thedarcyfluxtendstobeconcentratedinplasticfaultzonesdevelopingintheuppercrust.

Inamoregeneralsensetheresults indicatethatpartialmeltoriginatingintheuppermantlecanproducestress-relatedhigh-porosityzoneswhilepercolatingthroughatectonicallyactivecontinentalcrust.Wherebrittlefaultsarepresent,po-rousflowcanbeconcentratedtowardsthem.Onepossibleapplicationofthistypeofmodelscouldbetheemplacementofhydratedslabmeltsintotheoverridingplateinanocean-continentcollisionzone.

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Flow mechanisms in granitic ultramylonites

RüdigerKilian*,RenéeHeilbronner*,HolgerStünitz**,MarcoHerwegh****

*Geological Institute, University Basel, Switzerland (ruediger.kilian@unibas.ch)**Geological Institute, University Tromsø, Norway; ***Institute of Geological Sciences, University Bern, Switzerland

In theGranParadisometagranodiorite small scaleductile shearzonesdevelopedat loweramphibolite faciesconditions.Alongthestraingradientfromthehostrocktothecenteroftheshearzoneweobservethetransitionfrommm-sized,(1)non-recrystallizedigneousquartzgrainsto(2)entirelyrecrystallized,polycrystallinequartzaggregates,to(3)planar,poly-crystallinequartzlayersto(4)dispersedquartzgrainsinapolymineralicmatrix.Inthehigherstrainparts(3)thematrixconsistsofamixtureofplagioclase,K-feldsparandbiotite(+/-whitemica).Quartzisthemorecompetentrheologicalphasewhichisdemonstratedbythegeometricalrelationofthequartzclastsandthema-trix.Publishedexperimentallyderivedflowlawsalsosupportthisinterpretation.Withincreasingstrain,aggregatesbecomeelongatedandformlayersofdecreasingthicknessalternatingwithmatrixlayers.Thedominantslipsystemisbasal<a>leadingtoastrongtexturewithac-axisperipheralmaximumslightlyrotatedwiththesenseofshearwithrespecttothelocalfoliationasthereferenceframe.Ashapepreferredorientationdevelopscorrespon-dingtothec-axisorientation.Thegrainsizeremainsconstantthroughoutthestraingradientwithameanequivalentdia-meterofabout100µm(volumeweighted).Inthemosthighlystrainedparts(4)aphasemixturedevelopswithhomogeneouslydispersedquartzgrains.Thetextureofthequartzisweakened,theshapepreferredorientationsystematicallychangesfromamonoclinictoanorthorhombicgeo-metryandthequartzgrainsizedecreasestoameanequivalentdiameterof60µm(volumeweighted).The microstructural development with increasing strain is associated with a change from dislocation creep in quartz aggre-gates to granular flow. We present a model for the process of disintegration of quartz aggregates and the coeval grain size reduction. The dominant deformation mechanism is grain boundary sliding accommodated by solution transfer. We conclude that the quartz grain size reduction is primarily achieved by phase boundary migration, nucleation and growth. The disinte-gration of aggregates and the dispersion of grains reflect that processes involved during dislocation creep can not accommo-date grain scale strain incompatibilities in quartz at the stress level imposed by the matrix.

2.29

Comparing thin-sheet models with three-dimensional numerical models for the India-Asia collision

LechmannSarahM.*,SchmalholzStefanM.*,KausBorisJ.P.**&HetényiGyörgy***

*Geologisches Institut, Sonneggstrasse 5, CH-8092 Zürich (sarah.lechmann@erdw.ethz.ch)**Institut für Geophysik, Sonneggstrasse 5, CH-8092 Zürich***Institut für Mineralogie und Petrographie, Clausiusstrasse 25, CH-8092 Zürich

KnowledgeaboutthetectonicevolutionoftheTibetanPlateauisstillincompleteandmanyopenquestionsremainconcer-ningthedeformationstyleofthecrustalthickening,causingtheabnormallyhighelevationoftheTibetanPlateau.Differentmodelshavebeen suggestedexplaining the crustal thickeningby (1)homogeneous, continuousdeformationusing thin-sheetmodels, (2)discretemovementalongthrustsdevelopingcrustalwedgesand (3) lateralcrustal flowduetopressuregradientsresultingfromtopography.Mostexistingnumericalmodelsarenotfullythree-dimensional(3D)(e.g.thin-sheetmodels)andassumeacertaindeformationstyleapriori,whichmakesitdifficulttojudgetheapplicabilityofsuchcons-trainedmodelstotheformationoftheTibetanPlateau.Wepresentacomparisonofdeformationstylesduringcontinentindentationresultingfromafully3Dnumericalmodelandathin-sheetmodel.Therheologyforbothmodelsispower-law.The3Dmodelconsistsoffourlayersrepresentingasimplifiedlithosphere:stronguppercrust,weaklowercrust,stronguppermantleandweaklowermantle.Fromtheeffectiveviscositydistributionofthe3Dmodelaverticallyaveragedeffectiveviscosityiscalculatedandusedforthethin-sheetmodeltomakedirectcomparisonsbetweenthetwomodels.

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icsSimulatingindentationisachievedbyassigningatripartitevelocityprofileatonelateralboundary:Aconstanthorizontal

velocityisappliedatonesection.Thevelocitythengraduallydecreasestowardszero,applyingacosine-function.Thelastsectionoftheindentingboundary is fixed.Theotherthreelateralboundariesshowfreeslip.The3Dmodeladditionallyexhibitsafreesurfaceandabottomboundaryallowingfreeslip.

Inthe3Dmodelfoldingandlowercrustalflowcantakeplace,whicharetwodeformationstylesthatareignoredinthethin-sheetmodel.Wequantifythedifferencesinthevelocityfieldresultingfromthetwomodels.Wefocusonareasaroundtheindentationcorners(theso-calledsyntaxes)becausetherethedifferencesinbothmodelsareexpectedtobelargest.Also,theHimalayansyntaxesarefull3Dstructureswhere3Ddeformationeffectsareexpectedtobestrongest.Applicationsofthe3DmodeltogetherwithavailablegeophysicaldatatotheHimalayansyntaxesandtheIndia-Asiacollisionarediscussed.

2.30

Strain localization and the importance of second phases in polymineralic mantle shear zones

Linckensjolien*,HerweghMarco*,MüntenerOthmar**

* Institute of Geological Sciences, Baltzerstrasse 1+3, CH-3012 Bern (linckens@geo.unibe.ch)**Institute of Mineralogy and Geochemistry, l'Anthropole, CH-1015 Lausanne

LocalizationofdeformationinshearzonesisacommonfeatureintheEarth’scrustanduppermantle(e.g.,thrusts,strikeslipfaults).Theevolutionofsuchhighstrainzonesisoftenlonglasting,incorporatingvariationsinphysical(e.g.P,T)andchemicalconditionswithtime.Aspreviously inferred fromstudiesonperidotiteshearzones, secondphases (e.g. spinel,pyroxenes)canbeimportantinlocalizingstrainastheycankeeptheolivinematrixgrainsizesmall.Theinfluenceofsecondphasesontheolivinegrainsizeandtheiraffectonstrainlocalizationhasnotyetbeenquantifiedindetail.Todeterminetheimportanceofsecondphasesinlocalizingstraininthemantle,threedifferentperidotiteshearzones(WadiHilti,Oman;Othris,GreeceandLanzo,Italy)wereanalyzedandcompared.InthecaseoftheOmanandLanzoperidotite,arangeofmicrostructures, fromporphyroclastic tectonites toultramyloniteswere investigated. Thesemicrostructures arerelatedtocontinuouslocalizationunderretrogradeconditions.Inaddition,mylonitesamplesoftheOthrisperidotitewereanalyzed.Similartopreviousstudiesperformedoncalcitemylonites,eachofthedifferentmantlemicrostructurescanbesubdividedintotwodifferentmicrofabrictypes:(a)secondphasecontrolledmicrostructures,wheretheolivinegrainsizeincreaseswithincreasingZenerparameter(Z=dp/fp;secondphasegrainsize/secondphasevolumefraction)(b)recrystallizationcontrolledmicrostructures,wheretheolivinegrainsizeshowsnodependenceonthesecond-phasecontentandremainsconstantwithincreasingZ.Theolivinegrainsizeforbothmicrofabrictypesbecomessmallerwithdecreasingtemperatureandstrainrate.ThedifferentperidotiteshearzonesshowthesamerelationbetweentheZenerparameterandtheolivinegrainsizewhenthedeformationconditions(e.g.temperatureandstrainrate)werethesame.Fromageodynamicpointofview,Zenertrendscanthereforebeappliedasatooltodeterminethedeformationconditionsandtheirvariationsinspaceandtimeincaseofmantlerocks.TheCPOofolivineinthedifferentmicrostructuresweakensgoingfromporphyroclastictectonitestoultramylonitesandalsowithdecreasingZenerparameter.This indicates that,withongoingstrain localizationandwith increasingsecond-phasecontent,diffusioncreepbecomesmoreimportantasdeformationmechanism.ThecombinationoftheZenertrendwitholivinedeformationmechanismmapsandCPOisagoodmethodtoassesstheimportanceofsecondphasesonstrainlocalization.Inthiswaythedominantdeformationmechanismandstrainrateinthedifferentmicrostructurescanbederived.Theanalysisoftheperidotiteshearzonesshowsthatwhenthereisaswitchindominantdeformationmechanismbetweenpureolivineandpolymineraliclayersorwhenbotharedeformedbygrainsizesensitivedeformation,thestrainrateisuptoanorderofmagnitudelargerinthepolymineraliclayers.

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Numerical modeling of craton destruction

GangLu1,BorisKaus2,LiangZhao1

1 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China2 Geophysical Fluid Dynamics, Department of Earth Sciences, ETH,8092,Switzerland

Archeancratonsarecharacterizedbyacold,thick,stablelithospherekeel.TheNorthChinaCraton(NCC),however,isanan-omaly.TheeasternNCCexperiencedsignificantlithosphericthinningintheLateMesozoictoCenozoic.Inordertounder-standthemechanismsoflithosphericthinning,weperformedasetofgeodynamicexperimentsusingMILAMIN_VEP,whichisbasedonthefiniteelementmethod.Thesetupinvolvesaflathomogeneouslithospherewithathicknessof190km.Theinfluencesof(a)lithosphereextension,(b)uppermantleconvectionand(c)thermalanomalybeneathlithosphereareinvestigatedseparatelyorsimultaneously.Inthecasesof(a),apushvelocityisimposedtoextendthelithospherewhiletheendoflithosphereisreplacedbymaterialwithlowviscosity.Inthecasesof(b),thermalanomaliesatthebottomofthemodelareusedtostarttheconvection.Incasesof(c),hightemperatureanomaliesareimposedjustbeneaththelithosphere.Weconcludefromourinitialexperimentsthat:(A)simpleextensioncanthinthewholelithospherehomogeneouslyatthebeginningandbreakthelithospherebyanormalfaultfinally,(B)downwellingsdominateconvectionafterabout10Myrs,independentof the initialmagnitudeof the temperatureanomaly.Thebottomof lithospherecanbepartlydestroyedatcertainplaceswherestabledownwellingforms,andgetsthickenagainafterthedownwellingdisappears,(C)asimplehightemperatureanomalybeneathlithospherehaslittleinfluencetothelithospherethinning.Itisthussuggestedthatextensi-onisacandidatemechanismofdestroyingacraton.

2.32

New experimental approach to measure seismic wave attenuation of rocks at low frequency

ClaudioMadonna*,NicolaTisato*,SébastienBoutareaud*,BradArtman**andLuigiBurlini*

*Structural Geology and Tectonics, Sonneggstrasse 5, 8092 Zurich (claudio.madonna@erdw.ethz.ch)**Spectraseis AG , Giessereistrasse 5, 8005 Zurich

Wedescribeanewexperimentalapproachtoaccuratelycharacterizeattenuationinfluid-bearingporousrocksamples.Anewapparatushasbeendevelopedandbuiltinordertomeasureattenuation(1/Q)ofseismicP-wavespassingthrougharocksampleinthelowfrequencyregime(0.1Hz -50Hz),employingthestress-strainmethodinaninternallyheatedgasapparatus(Patersonrig).Stressismeasuredwithaloadcellof1000Nfullscalewitharesolutionof0.01N.Strainismeasuredwithhigh-sensitiveLVDTsof1mmfullscaleandaresolutionof10-9m.Thisnewapparatusdiffersfrompreviousonesinthatitcanmeasurethebulkattenuationofanon-isotropic,non-homogeneous50-to-100mmlengthsamplebyavoidingstraingauges.Thequality factorQ isobtained fromthetimeshiftbetweenthesinusoidal stress,which ismechanicallyappliedat thebottomofthesample,andthesinusoidalstrainresponsemeasuredonthetopofthesample.Wepresentasketchoftheapparatusandweincludeadiscussionofsomeoftheproblemsencounteredwhilebuildingtheapparatus;wefurtherdiscussrecentimprovements.Inaddition,wepresentpreliminaryresultsandthecorrespondingdigi-talsignalprocessingonaluminium(asstandard)andBerea-sandstonepartiallysaturatedwithoilandwaterandcharacteri-zedbymeansoftomographicimages.Thisnewtechniquecanbeusedtoaccuratelyestablishacatalogof1/Qvaluesasafunctionofin-siturockproperties. Inparticular,futurestudiesusingthisapparatuswillinvestigatetheeffectsofdifferentfluidpropertieson1/Q.Suchnew,ac-curatemeasurementswillbeimportantinpassiveandactiveseismicinvestigationsonfluid-bearingrocks.

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The Singularities of double subduction systems

Malatesta,Luca*;Mishin,Yury*;Gerya,TarasV.*

*Institute of Geophysics, ETH-Zurich, Sonneggstrasse 5, 8092 Zurich, Switzerland

Amongthetectonicprocessesoccurringat thesurfaceof theEarth, thedoublesubductionsystemsaresomeof the lessstudied.Bydoublesubductionsystem,weunderstandaconfigurationinwhichtheforceofaoneortwo-sidedaccretionistranslatedintwodistinctsubductionsnexttoeachotherdippinginthesamedirection.Theyarerelevantforbothmodern(Izu-Bonin-MarianasandRyukyuarcs,Hall(1997))andancienttectonics(westernHimalayas,Burg(2006)).Nexttotheirdocu-mentationinthefield,fewexperimentshavebeenperformedtounderstandtheirdynamics.Thefirstandonlynumericalmodelingoftheproblemuntilthepresentresearchhasbeensuccessful indeterminingthedynamicsofasimplemodel(Mishin,2008).Weperformedfurtherexperimentswiththesame2Dcoupledpetrological-thermomechanicalcode(GeryaandYuen,2003)butinamorecomplexsetup.Itencompassedanoceanicplatecontainingtwoweakzonesandboundwithtwocontinentalplates,oneofwhichmovingconstantlytowardstheother.Westudiedtheeffectsoffourkey-parameters:theageoftheoceanicplate,theactivationvolumeofthedislocationcreep,thecompositionoftheoceaniccrustandthelengthofthefirstsubductingslab(figure1).Theexperimentsledustotheconclusionthat(A)theageofanoceanicplateandtheactivationvolumeinfluencethesubductionssystemasfollow:theyare(i)linearlyandproportionallyrelatedtothebreak-offtimeand(ii)inverselyproportionaltotheroll-backpower.(B)Therelativethicknessofgabbrointhecrusthasdistincteffectsonthedippingslab:itis(i)inverselyproportionaltothebreak-offtimeand(ii)proportionaltothe660kmentryangle(C)Thesubductionregime(advancing,penetratingorretreatingmode)dependsontheslabentryangleinthe660kmdiscon-tinuityzone.Theentryanglesumsuptheotherparameters.Keyanglesdeterminingthedifferentregimesweredeterminedforagivenslablength.(D)thelengthofthefirstsubductedslabimpactsthegeometryoftheglobalsystembutdoesnotchangeitsdynamics.(E)Simultaneoussubductionscannotbeobtainedinaone-sidedaccretionwiththeinvestigatedmodel,furtherelements–absentfromthemodeling–shouldaccountforit.(F)Thesubductionregimeandorientation(i)canbepossiblyregainedthroughthestudyofsedimentationrecordbut(ii)isnotcoherentlylinkedtothestyleofthefinalorogeny.(G)Doublesubductionsystemsleadtoacomplexbasinevolutionoffore-andback-arcsandpro-andretro-forelands,andtoaspecificoverridepatternwhichcanmisleadtheinterpretationofthesubductionorientation.

Figure1.Evolutioninthreestepsofadoublesubductionnumericalmodel.Withthechemicalcompositioninthefirstrow,thevelocityin

thesecondandtheviscosityinthethird.

REFERENCESJ.-P.Burg.Twoorogenicsystemsandatransform-transferfaultintheHimalayas:evidenceandconsequence.EarthScience

Frontiers,13:27-46,2006.T.V.Gerya andD.A. Yuen.Characteristics-basedmarker-in-cellmethodwith conservative finite-difference schemes for

modellinggeological flowswith strongly variable transportproperties. Physicsof theEarthandPlanetary Interiors,140:295-320,2003.

R.Hall.CenozoicplatetectonicreconstructionsofSEAsia.GeologicalSocietyLondonSpecialPublication,126:11-23,1997.Y.Mishin,T.V.Gerya, J.-P.Burg,and J.A.Connoly.Dynamicsofdouble subductions:Numericalmodeling.Physicsof the

EarthandPlanetaryInteriors,171-280-195,2008.

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CitcomSX: Robust preconditioning in CitcomS via PETSc

DaveA.May*,MatthewG.Knepley**,MikeGurnis***

* Department of Earth Sciences, ETH Zurich, Zurich, Switzerland (dave.mayhem23@gmail.com)** Computation Institute, University of Chicago, Chicago, IL, USA (knepley@gmail.com)***Computational Infrastructure for Geodynamics, California Institute of Technology, Pasadena, CA, USA (gurnis@gps.caltech.edu).

Theuseofnumericalsimulationstostudyconvectioninthemantlehasalongandrichhistoryingeodynamics.TheCitcomfamilyofmantleconvectioncodesareinwidespreadusethroughoutthegeodynamicscommunity.SincetheinceptionoftheoriginalCartesianversionwrittenbyLouisMoresiintheearly1990's,manyvariantshavebeendeveloped.TwoimportantcontributionsweremadebyShijieZhongintheformoftheparallel3DCartesianversionandtheparallel,fullsphericalversion.

TheComputationalInfrastructureforGeodynamics(CIG)havebeenprovidingmaintenanceandsupportforCitcomSoverthe last5years.TheCIGeffort toprovideacommunitymantleconvectioncodehas resulted in severaldevelopments toCitcomS.Theseincludetheadditionofnewphysics(rheology,compressibility),couplingwithothersoftware,theinclusionofadditionalgeologicallyrelevantinput/outputsandimprovedportability.SuchimprovementshaveseenafurtherincreaseinthedevelopmentandusageofthisparticularversionofCitcom.Today,CitcomSisroutinelyusedtosolvemantleconvec-tionandsubductionmodelswithapproximatelyonehundredmillionunknownsonlargedistributedmemoryclusters.

Manyadvanceshavebeenmadeinbothnumericallinearalgebraandthesoftwareencapsulatingthesemathematicalcon-ceptssincethedevelopmentoftheoriginalCitcom.However,thesolverusedbyallCitcomsoftwarehasremainedlargelyunchangedfromtheoriginalversion.IncorporatingmoderntechniquesintoCitcomShasthepotentialtogreatlyimprovetheflexibilityandrobustnessoftheiterativemethodsusedtosolvetheunderlyingsaddlepointproblem.HerewedescribehowPETSc(http://www.mcs.anl.gov/petsc),aflexiblelinearalgebrapackage,hasbeenintegratedintoCitcomSinanon-inva-sivefashionwhichi)preservesallthepre-existingfunctionalityandii)enablesarichinfrastructureofpreconditionedKrylovmethodstobeusedtosolvethediscreteStokesflowproblem.The"extension"ofthesolvercapabilitiesinCitcomShaspromp-tedthisversiontobereferredtoasCitcomSX.

WedemonstratetheadvantagesofCitcomSXbycomparingtheconvergencerateandsolutiontimeofthenewStokessolverwiththeoriginalCitcomSapproach.WeutiliseascaledBFBtpreconditionerwhichisconstructedviatheassumptionoftheexistenceofanapproximatecommutatorasapreconditionerfortheSchurcomplement.TheBFBtpreconditioneriscompo-sedofsmallersub-problemsforwhichefficient,robustandscalablemultilevelmethodsexist.HerewedemonstratethatthescaledBFBtweutiliseisrobustandyieldsconvergencerateslargelyindependentoftheelementresolutionandtheviscositycontrast.Usingthispreconditioner,wecanaccommodatehigherviscositycontrasts thanwerepossiblewiththeoriginalCitcomSsolver.Thetestproblemsusedforthesecomparisonsincludesimulationsofvariableviscositymantleconvection(regional,fullspherical)andslabsubduction(regional).

2.35

Seismotectonic study in Northern Tunisia (exemple: Utique Structure)

LassaadMejri1,2,4,5,VincentRegard1,2,3,SébastienCarretier1,2,3,StéphaneBrusset1,2,3,MahmoudDlala5

1. Université de Toulouse ; UPS (OMP) ; LMTG ; 14 Av Edouard Belin, F-31400 Toulouse, France 2. CNRS ; LMTG ; F-31400 Toulouse, France3. IRD ; LMTG ; F-31400 Toulouse, France4. CNSTN, Pôle technologique 2020 Sidi Thabet, Ariana, Tunisie5. Université de Tunis El Manar ; Faculté des Sciences de Tunis, 1060 Tunis, Tunisie

Thepresent-dayseismicityatnortheasternTunisiareportedfrompermanentnetworks isof lowtomoderatemagnitude.However,earthquakesarementionedintheliterature,speciallyadestructiveoneintheantiquecityofUtique.Geologic,seismic,andneotectonicinvestigationsinthisareashowsthatUtiquefoldiscloselyrelatedtotherecenttectonicactivityinthisregion.DatashowthatUtiquefoldisbuiltonanE-Wfault,andwefoundevidenceofactivityofthisfaultinthepast20ky.Seismicsectionandbalancedcrosssectionshowsthatitwasaffectedbytwophasesofcompressionaldeformation.The

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icsfirstoneisoccurredduringMioceneandcausedfoldingoverapassiverampinTriassicsediment.Thetimingofthesecond

oneisunclearbecauseoflowdefinitionofseismicdatainitsuppermostpart:itclearlyoccurredafterSerravalian.Atotalshorteningof690mhasbeenmeasuredindicatinganaverageshorteningrateof0.14mm/yrsincethebeginningofPliocene.Asalreadymentioned,compressionmusthavebegunearlyinPleistocene(1.8My);thisleadstoamostlikelyvalueforshor-teningrateof0.38mm/yr,corresponding to~8%of thecurrent shortening inTunisia (~4.5mm/yr inadirectionN145°EbetweenstableAfricaandSardiniaafteracompilationofresultsfromD’AgostinoandSelvaggi[15]andHollensteinetal.).Fieldobservationsofsurfacefaulting,debrisoflessthan2000yearsoldpotteryreworkedandpossiblytiltedcalcareousno-dulesatthefaultzonesuggestthatthemaincompressionalphasecontinuesuptopresent.Utiquefaultoutcropsinagully~5mwideand~5mdeep.Thegullyseemstohaveexperiencedacomplicatedstorywithafirstincisionstagefollowedbyrecentfillingandrenewedincisionthatcontinuescurrently.Afaultplanewasfound,displa-yingimportantvariationsintrendanddip;theaveragevaluesbeingaN150°Etrendandan80°Ndip,withuncertaintiesevaluatedtobe~20°.ThefaultoffsetsclearlysomeconglomeratesmadeofPliocenemarineformationreworkingandgrayclaylevels,observedelsewherelyingontopofcalcrete.Itismantledbytherecentgullyinfillingmadeofangulardebris,whichcouldhavebeenaffectedbythefault.Inbetween,anoncontinuousformationmadeofclayandcalcrete-derivedsandscouldbeobserved;itisapparentlyfaultedandcontainsapieceofpottery,lessthan2000years-oldafteranarcheologistex-pertise(SlimKhosrof,NationalInstituteofPatrimony,Tunis,personalcommunication)OurdatashowdefinitivelythelatePleistocene–HoloceneactivityoftheUtiqueFault;andwecanpredicttheearthquakerecurrenceintervalwhichshouldbeof~103-104yr.ThismakestheUtiquefaultpropagationfoldanimportantstructurewhenregardingseismologicalhazardofthe1.5MpeopleTunisCity,located35kmtothesouth.Thishighseismicriskzonedeser-vestobetakenintoaccountduringtheestablishmentofimportantregionaldevelopmentprogramsandintheapplicationofseismicbuildingcode.

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s 2.36

Numerically modeling current vertical surface motion in the swiss alps from the bottom up - Does the geometry of the orogen dictate how it moves?

MettierRalph*

*Institut für Geologie, Baltzerstrasse 1-3, CH-3012 Bern (mettier@geo.unibe.ch)

Apart fromtheobvioustopographical features, theongoingsurfacemotion isoneof themosteasilyaccessibleandbestquantifiablecharacteristicsofatypicalalpine-styleorogen.However,itisoftenunclearastohowmanydifferentprocesses,suchasi.e.isostaticadjustmenteffects,contributetotheobservedmotion,andhowmuchissimplyaconsequenceoftheongoingshortening.Recentadvancesinseveralmethods,suchasenhancedGPSmeasurements,InterferometricSyntheticApertureRadar(InSAR)andfissiontrack(FT)dating,aswellaspreciselevelingcannowprovideuswithagooddescriptionoftheverticalmotionatpresentandinfairlyrecenthistoryoftheorogen.Thisin-turn,providesuswithfresh,andoftenmuchneeded,criteriaforcalibratingourconceptualandnumericalmodelsoforogenesisandtheinvolvedprocesses.Wepresentaseriesoffiniteelementmodels,thatattempttoreproducedtheobservedverticalsurfacemotiononaroughlynorth-southcrosssectionoftheSwissAlps.Whilefairlysimpleasfarasrheology,thermodynamicsandvariousotheraspectsareconcerned,thegeometryofthecrosssectionsisofhighcomplexity,representingindividualtectonicunitssuchastheAar-andGotthardmassifs,theHelveticandPenninicnappestructuresaswellastheunderlyingsubductionoftheeuropeancrust.Themodelssimulateashortspanofacceleratedtime,withafixedrateofshorteningprescribedbytheboundaryconditions.Theresultingmotionatthesurfaceofthemodel,aswellastheinternaldeformationoftheindividualtectonicunitsisthenexamined,interpretedandcomparedtotheirreal-worldcounterparts.Themodelseriesincorporatesvariationsinthecho-senphysicaldescriptionsofthematerials,deformingbothpurelyelasticandpartiallyelasto-plastic,aswellasinthedescrip-tionofthefrictionalbehaviourattheinterfacesbetweenunits.Furtherparametervariationswithinthesemodelsub-seriesprovideinsightintotherelativerelevanceoftheseparameters.Perhapsunexpected,consideringthesimplicityofthemodels,theresultsexhibitgoodcorrelationwiththedataobtainedfromreal-worldmeasurements.Thisleadsustospeculatethattheunderlyinggeometrymaywellbethedominantfactorindescribingthebehaviourofsuchanorogen.

2.37

Seismic properties of melt-generating metapelites

SantanuMisra*,BjarneSvenGustavAlmqvist**andLuigiBurlini*

*Geological Institute, **Institute of Geophysics; ETH Zurich, CH-8092, Switzerland

Weperformedultrasonicpulsetransmissionmeasurementsonsyntheticrocksofpeliticcompositiontoidentifytheirseis-micpropertiesanddeterminethecompleteelastictensorduringpartialmeltgeneration.Experimentswereconductedat750oCand300MPaconfiningpressureoncylindricalsamplesofquartz-muscoviteaggregates(1:1byvolume)havinganinter-nal,transverselyisotropicplanarfabricand~24%porosity.Thevelocitiesofcompressionalwaves(V

p)andextensionalwaves

(VE)weremeasuredcontinuouslyfor6hoursatdifferentfrequencies(0.1,1.0and3.0MHz)withwavespropagatingat0,45

and90owithrespecttotheaxisofsymmetryofthesamples.Shear-wave(Vs)velocitiesweredeterminedindirectly,basedon

theVEandV

P.Inthebeginningoftheexperimentsthereductionofporositywithconfiningpressureandtemperaturelead

toanincreaseoftheseismicvelocitiescomparedtoroompressureandtemperature.Vpdecreasedby200-400m/swiththe

onsetofmeltgeneration,whichstartedafter1.5hoursoftheexperiment.Acomplexbehaviouroftheseismicvelocitieswasobservedwithincreasingmeltgenerationandnucleationofnewcrystals.Theseismicanisotropyvariesforthedurationoftheexperiment,andisdependentonthesamplehistory(i.e.,porosityreduction,meltgeneration,crystalnucleation).Theseexperimentalresultscansuitablybeappliedtogeophysicalinvestigationofthelowercrustwherepartialmeltingisanim-portantgeologicalprocess.

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Rheology of metapelites during partial melting and crystallization

SantanuMisra,ElizavetaTumarkina,LuigiBurliniandJean-PierreBurg

Structural Geology and Tectonics Group, Geological Institute, ETH, Sonneggstrasse 5, Zurich 8092, Switzerland

This study investigates the rheological behaviour of metapelitic rocks at depth where they undergo synkinematic partial mel-ting and subsequent crystallization during progressive deformation. Torsion experiments were performed on synthetic pelitic rock samples at 300 MPa confining pressure and 750oC temperature with a constant strain rate ( =γ& 3x10-4) for a range of finite shear strains (γ = 0.5-15). Partial melting started a relatively low shear strains (γ = 2-4), which was coupled with strong strain softening (~ 60%) in the creep behaviour. With further shearing (γ = 4-10) the creep turned to be steady state flow with nucleation of tiny, new crystals. At higher shears (γ = 10-15), new mineral phases started growing at the expense of partial melts, which resulted in weak strain hardening and finally, brittle failure of the sample at the same pressure-temperature.

The stress exponent values (n) were continuously increasing from 3 to 28 with progressive deformation indicating a transition from power to exponential flow law (power Law Breaking). Depending on the melt and solid proportions in the system the speculated four stages of percolation thresholds during partial melting and crystallization of lithosphere were established by the experimental data.

2.39

Palaeotethyan, Neotethyan and Pindos series in the Lycian Nappes (SW Turkey): geodynamic implications

MoixPatrice&StampfliGérardM.

Institut de Géologie et de Paléontologie, Université de Lausanne, Bâtiment Anthropole, CH-1015 Lausanne (Patrice.Moix@unil.ch)

Foralongtime,theideaofacontinuumbetweentheHellenidesinGreeceandtheTauridesinTurkeyhasbeendiscussed(e.g.,Brunnetal.,1976).ThiswasprincipallybasedoncorrelationsbetweentheplatformseriesoftheexternalpartsoftheHellenides-Taurides system, as well as similarities between sedimentary sequences in southwestern Turkey and in theDodecaneseislands(e.g.,Bernoullietal.,1974).InsouthwesternTurkey,theLycianNappesoccupyalargeareabetweentheBeydağlarıplatformtothesoutheastandtheMenderesMassiftothenorthwest.IthasbeendemonstratedthattheLycianNappesarederivedfromtheIzmir-AnkarabeltandrepresentallochthonouspartsofthenorthernpassivemarginoftheAnatolianterrane(Moixetal.,2008).BecauseoftheirlocationbetweentheHellenicsystemtothewestandtheTauriconetotheeast,theLycianNappesandtheirpara-autochthonousseriesareakeyarea.TheTavasNappeformsthelowermostunitintheLycianpileandisclassicallysubdividedintotheKaradağ,TekeDere,KöyceğizandHaticeanaunits(deGraciansky,1972).DetailedfieldworksupportedbynumerousmicropalaeontologicalevaluationsmakeobviousthattheTavasNappeisinrealityhighlycomposite.

ThelowermostKaradağunitconsistsofaplatformsuccessionrangingfromtheLateDevoniantotheLateTriassic.AlargehiatusoutlinedbythedepositionofsandstoneandquartziteexistsbetweentheSakmarianandtheMiddleTriassic.TheCarnianismarkedbyageneraldeepeningoftheplatformprecedingshortlythedepositionofawildflysch-likeformation.ThediscoveryoftheCordevolian(earlyCarnian)PseudofurnishiusmurcianusmurcianusvandenBoogaardconodontfaunaontopoftheplatformandinthefirstlimestonebedsinterstratifiedatthebaseofthesiliciclasticformationisofcrucialim-portance.ThisfaunacharacterizestheSephardicprovinceandisatypicalindicatorfortheNeotethyandomainsensustricto.ThePalaeozoicsuccessionoftheKaradağunitisatypicalshallow-waterGondwanatypeshelfdevelopmentandcanbecom-paredtosimilarsectionsintheAlborzrangeinnortheasternIran.ThelargehiatusduringthePermiancouldbeseenasariftshoulderrelatedtotheNeotethyan(=East-Mediterranean)rifting.Consequently,theKaradağunitlikelybelongstotheCimmerianTaurusterraneandwaspartofthenorthernpassivemarginoftheNeotethys.

TheKaradağunitisalwaysfoundstructurallybelowtheTekeDereunit,thissuperpositionbeingapossibleresultoftheLateTriassicEo-Cimmerianorogenicevent.TheTekeDereunitincludesseveralslicescomposingthemostcompletePalaeotethyansuccessioninTurkey.ItcomprisesKasimovianOIB-typebasaltsandassociatedplatformandslopesedimentsrepresentingaPalaeotethyanseamount,CarboniferousMORB-typebasalts,anEarlyCarboniferoussiliciclasticseriesstratigraphicallyover-lainbyMiddlePermian limestones, andaMiddlePermianarc sequence.Both theplatform limestonesassociated to the

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s seamount and the dolostones above the Early Carboniferous siliciclastic series yielded shallow-marinemicrofauna andmicroflora sharing strong biogeographical affinities with the northern Palaeotethyan borders. Palaeotethyan remnantsfoundassubduction-accretionarycomplexesorreworkedduringtheEo-CimmerianorogeniceventprovideastrongmeantoidentifyandlocatethePalaeotethyansuturezone.

ThethickMesozoicsequence,formedbytheKöyceğizandHaticeanaseries(bothofthembelongingtothesamepalaeogeo-graphicrealm),occupiesahighstructuralpositionabovetheKaradağandTekeDereunits.ThebaseoftheseriescomprisesLateTriassiccontinentalredarkosicsandstonesandconglomerates.Thismolasse-likesedimentationisfollowedbyLiassicshallow-marinelimestoneandincludesalateLiassicAmmoniticoRosso.ThesedimentationcontinueswithlateLiassictoMaastrichtianpelagicmicrites,chertymicritesandcalciturbidites.ItisthenunconformablyoverlainbyalatePalaeocenetoLutetianflysch.Atplaces,LateTriassicvolcanicrocks(transitionalMORB-type)associatedtopelagiclimestones,turbiditicsandstones, and calcareous sandstones alternating with volcaniclastic sediments form the lowermost exposure of theKöyceğizseries.ThissedimentologicalevolutionisinmanypointssimilartoPindos-likeseriesfoundnowinsouthernTurkeyandintheDodecaneseislands.TheseseriesoriginatedintheHuğlu-PindosOcean,alongthenorthernpassivemarginoftheAnatolian(Turkey)andSitia-Pindos(Greece)terranes(Moixetal.,2007).

Inconclusion,theTavasNappeincludesmoreorlessdismemberedunitsbelongingtothePalaeotethyan,NeotethyanandHuğlu-Pindosrealms.TheKaradağunitbelongstotheNeotethys(=East-Mediterranean)domain,theTekeDeresuccessioniscomposedofseveralthrustsheetsofPalaeotethyanorigin,andtheKöyceğizandHaticeanaseriesarerelatedtotheHuğlu-Pindosoceanicdomain. The identificationof such remnants in the LycianNappes and their comparisonswithadjacentareasofferefficienttoolstomakeaccurategeologicalcorrelationsbetweenGreeceandTurkey.

REFERENCESBernoulli, D., de Graciansky, P.-C. andMonod, O., 1974. The extension of the LycianNappes (SW Turkey) into the

southeasternAegeanIslands.EclogaeGeologicaeHelvetiae,67(1):39-90.Brunn,J.H.,Argyriadis,I.,Ricou,L.-E.,Poisson,A.,Marcoux,J.,deGraciansky,P.-C.,1976.Elémentsmajeursdeliaisonentre

TauridesetHellénides.BulletindelaSociétéGéologiquedeFrance,18(2):481-497.Gracianskyde,P.-C.,1972.RecherchesgéologiquesdansleTaurusLycien.PhDThesis,ParisSud-Centred'Orsay,Paris,762

pp.Moix,P.,Kozur,H.W.,Stampfli,G.M.andMostler,H.,2007.Newpalaeontological,biostratigraphicalandpalaeogeographical

results from theTriassic of theMersinmélange, SE Turkey. In: S.G. Lucas and J.A. Spielmann (Editors), The globalTriassic.NewMexicoMuseumofNaturalHistoryandScienceBulletinv.41,Albuquerque,pp.282-311.

Moix,P.,Beccaletto,L.,Kozur,H.W.,Hochard,C.,Rosselet,F.andStampfli,G.M.,2008a.AnewclassificationoftheTurkishterranesandsuturesanditsimplicationforthepaleotectonichistoryoftheregion.Tectonophysics,451(1-4):7-39.

2.40

New constraints on foreland basin development in South-West Taiwan from sequence stratigraphy and flexure modelling

StefanNagel*,SébastienCastelltort*,FredericMouthereau**,AndrewT.Lin***,SeanD.Willett*&BorisKaus*

*Eidgenössische Technische Hochschule (ETH) Zürich, Sonneggstrasse 5, 8092 Zurich, Switzerland, stefan.nagel@erdw.ethz.ch** Université Pierre et Marie Curie - Paris VI, Laboratoire de Tectonique - CNRS UMR 7072, Barre 46-45 Niveau 2 - Case 129, 4, Place Jussieu F-75252 Paris Cedex 05 France*** National Central University, Basin Research Group, Earth Science Dep. No.300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan(R.O.C.)

TheislandofTaiwanissituatedontheboundarybetweenthePhilippineSeaPlateandtheEurasianplateandhaslongbeenput forward as a textbook example of an Arc-Continent collision. Oblique arc-continent collision began during the lateMioceneandhasresulted inprogressivemigrationofactivedeformationandforelandbasindevelopmentfromnorthtosouth.Thusthenorthernpartoftheforelandbasinisdominatedbyshallowmarineandnonmarinedeposits,whereasthesouthernpartof the forelandbasin isdominatedbydeepermarinedeposits (Covey, 1984). The forelandbasin systemofWesternTaiwanrecordedinfillfromboththeChineseMainlandaswellasfromtheemergingTaiwanIsland.Furthermore,thehighratesofconvergence,highrateofrockupliftandthewet,stormyclimateofthesub-tropicaltyphoonbeltcombinetoproduceerosionandsedimentyieldratesamongstthehighestintheworld.Today,theTaiwanStraitisabout150to200

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icskmwideandaround70mdeep.However,thetimingofthedevelopmentoftheforelandbasinandsubsequentchangeof

directionofpaleocurrentisnotyetwell-defined.Differentauthorsdescribedabasalunconformityonseismicprofilesoff-shoreTaiwan,whichwasdated±6.5Ma(lateMiocene),buthasnotyetbeensupportedbyonshoreobservations.WeanalysedtwoPlioceneFormationsintheCentral(MeishanCounty)andSouthpart(TsengwenReservoir)ofTaiwan:theKueichulinFormation(TawoSandstoneMember)andtheAiliaochiaoFormation.Weconductedseverallithofacies(e.g.heavyminerals,thinsections,etc.)andbiostratigraphicalanalysisinordertounderstandtheregionalsequencestratigraphyandtobeabletosetupapaleoenvironmentalinterpretationofthestudiedarea.TheTawoSandstoneMemberbasicallyconsistsofwavy,lenticularandflaserbedded,thinlaminatedSilt-andMudstonesinterbeddedwithsmall,finetomediumgrainedsandstones(thickness:10cmto5m).Thesiltstonefaciesshowsrhythmicvariationsinlaminaethicknesswithconspicuousbidirectionalcurrentripplesindicatingatidalinfluence.Thesandstonefaciesare(inplaces)dominatedbybioturbationandphysical sedimentary structures, suchas scoured surfaceswith lagdeposits, low-angle cross-lamination, flaserandwavybeddingontop.Thetrace-fossilassemblageincludesstructurestypicalofboththeSkolithosandCruzianaichnofacies,characterizingashallow-marine(shoreface)environmentinwhichhigh-energyandlow-energysettingscoexis-ted. Similar lithofacieshavebeendescribed from tidally influenced continental shelf environments in SouthKorea andChina.

TheAiliaochiaoFormationmoretotheSouthconsistsoffinelaminatedsiltstoneandinterbeddedmudstonelayers.Theyareunconformably incisedbynumerous finegrainedsandstone layers formingcut-and-fill structureswithdistinctclimbingripplesintwooppositedirectionswithinawiderchannel.Inthemiddleofthechannelaxisexistconspicuousconglomerateswithfinegrainedsandymatrixcontainingmudclastsandforams.Bioturbationiscommonlyveryrare.ThesuccessivesedimentationoftheChinshuiShale(andtheequivalentMaopuShalerespectively),commonlyinterpretedasdeepermarinesediments, indicatesa formativeTransgressionevent.Theassociatedsea levelrise is interpretedastheonsetofloadinducedsubsidencebythegrowingorogen.Weinterpretthetwosectionsastransitionfromashallowmarine,tidallyinfluencedenvironmentwith(protected)lagoonsandestuariespassingintoachannel-leveesysteminproximalpartsofagrowingprodelta.Thespatio-temporalhistoryoftheWesternforelandbasinisinterpretedasanevolutionfroman“under-filled”stagewithmarinedepositional environmentsdeepeningupwards and relatively low sedimentation rates (Kueichulin fmand lowerChinshui fm) towardan“over-filled”stagemarkedby the fillingof thebasinwithprogressively shallowerenvironmentsupwardsandeventuallybecomingcontinental.Theprojectwillfocusonthehigh-resolutionstratigraphicrecordofthecollisioninthewesternforelandbasinbycompilingpublishedandunpublisheddata,collectingnewfieldobservationsandusingsubsurfaceseismicimaginginthebasininordertoreconstructpaleogeography,depositionalenvironment,andtectonicandsediment-transportcontrolsondepositio-nalpatterns.Theseresultswillserveasinputtostratigraphicand3Ddeformationmodelstoconstrainthedevelopmentoftheorogenanditssouthwardpropagation.Theresultsofthisstudywillprovideimportantevidenceforthespaceandtimeevolutionoftheorogen-relatedloadingoftheforeland.

REFERENCESCovey,M.,1984:SedimentaryandtectonicevolutionofthewesternTaiwanForedeep,UnpublishedPh.D.thesisCovey,M., 1984: Lithofacies analysis and basin reconstruction, Plio-PleistoceneWestern Taiwan Foredeep, Petroleum

GeologyofTaiwan,Vol.20,pp.53-83Lin,A.T.,A.B.WattsandS.P.Hesselbo,2003:CenozoicstratigraphyandsubsidencehistoryoftheSouthChinaSeamargin

intheTaiwanregion.BasinResearch,15(4),453-478.Mouthereau, F., andO. Lacombe, 2006: Inversion of the Paleogene Chinese continentalmargin and thick-skinned

deformationintheWesternForelandofTaiwan,JournalofStructuralGeology,28,1977-1993.

Funding:ThisprojectisfundedbySwissNationalFundsgrant#2-77295-08.

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Thermal structure and metamorphic evolution of the Piedmont-Ligurian metasediments in the Western-Central Alps

NegroFrançois*,PelletClara-Marine*,**,BousquetRomain**,BeyssacOlivier***,GuerraIvan****,VilsFlurin*****

* Institut de Géologie et d’Hydrogéologie, Université de Neuchâtel, Rue E. Argand 11, CH-2009 Neuchâtel (francois.negro@unine.ch)** Institut für Geowissenschaften, Universität Potsdam, Germany*** Laboratoire de Géologie, Ecole Normale Supérieure, Paris, France**** Institut de Minéralogie et Géochimie, Université de Lausanne, L’Anthropole, CH-1015 Lausanne***** Department of Earth Sciences, University of Bristol, UK

TheWestern-CentralAlps,locatedbetweentheSimplonandtheAosta-Ranzollafaults,representa"transition”zonewheremanypaleogeographicdomainswerecontinuouslyaccretedwithinthealpineorogenicwedge.Withinthisorogenicwedge,thePiedmont-LigurianoceanicdomainrecordedblueschisttoeclogitemetamorphicconditionsduringtheAlpineorogeny.ThePiedmont-Ligurianzone,isclassicallydivided,accordingtotheirmetamorphicevolution,intoaLP(greenschisttoblue-schistfacies)unit(Combinzone),andaHPtoUHPunit(Zermatt-Saasnappe).Thecontactbetweenbothzoneissupposedisamajordetachmentfault(Combinfault).AlthoughP-TconditionsarequitewellknownintheZermatt-Saasnappe,quantita-tiveconstraintsarelackingintheCombinzone.WeinvestigatedthetemperaturerecordintheoceanicmetasedimentsofthePiedmont-Ligurianunits,usingRamanspec-troscopyofcarbonaceousmaterial.Thismethodallowsquantifyingthemaximumtemperature,andthereforethepeakofmetamorphism,withoutbeingaffectedbytheretrogradeevolution.Theaimofthisstudywasto(1)estimatethepeaktem-peraturereachedwithineachunit(2)comparethetemperaturerecordbetweenthedifferentunits.Weadditionallycharac-terizedthemetamorphicassemblagesinthemetasedimentsofbothunits.SampleswerecollectedinthemetasedimentsoftheCombinzonenorthandsouthoftheDentBlanchemassif,andintheZermatt-SaasnappeintheareaofZermattandLagodiCignanatoestimatethetemperaturegapacrosstheCombinfault.IntheCombinnappe,temperaturesrangebetween430-500°C,andareverycoherentinthenorthernandsouthernpartsoftheDentBlanche.IntheZermatt-Saasnappe,temperaturesaresimilartotheonesobtainedintheCombinnappe,alsointherange450-530°C,andthetemperaturegapissignificantlylowerthanitisproposedintheliterature.However,mineralassemblagesarenotwellpreservedintheCombinnappecomparedtotheZermatt-Saasnappe,whichcouldbeexplainedbyintenseretrogression.Wecomparethesetemperatureswiththemetamorphicassemblagesobservedinthedifferentunitsanddiscusstheseresultsintheframeofthetectono-metamorphicevolutionofthehigh-pressurelow-temperatureoceanicunitsfromtheWestern-CentralAlps.

2.42

Influence of faults on the development of Excavation Damaged Zone: the case of the Mont Terri Rock Laboratory

NussbaumChristophe*&BossartPaul*

*Federal Office of Topography swisstopo, Fabrique de Chaux, CH-2882 St-Ursanne (christophe.nussbaum@swisstopo.ch)

Oneconcernintheresearchonwastedisposalinargillaceousrocksistheunderstandingofprocessescontrollingthedevel-opmentoftheExcavationDamagedZone(EDZ).ThegeometryandkinematicsoftheEDZfracturenetworkprovideavaluableinputforthisproblematic.However,theMontTerrisiteischaracterisedbyacomplextectonicsettingmadeofnumerousfaultswithdifferentorientationsanddips.Thesepre-existingfaultsorinheritedstructures,relatedtotheJurathrust-andfoldbeltandtotheRhine-Bressetransversezone,stronglyinterfereonthecreationofEDZfractures.Numerousfieldobser-vationsindicatethattectonicfaultscontroltheinitiationandlocalisationofEDZfractures.Forthisreason,itiscrucialtohaveaperfectknowledgeofthetectonicpattern.Systematicsmall-scalemappingofthetunnelwalls,floorandadjacentnichesprovidesbasicinformationaboutthegeometryandkinematicsofthegeologicalfracturesintersectedintheunder-groundrocklaboratory.Theobservedtectonicfaultscanbedividedintothreedifferentfaultsystems(Nussbaum&Bossart,2008):i)SSEdippingfaults(mainlyformedbybedding-parallelslipduringthefoldingoftheMontTerrianticline);ii)low

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icsangleSWdippingfaultplanesandflat-lyingSSEtoSdippingfaultplanesandiii)NtoNNEtrendingsteeplyinclinedsinistral

strike-slipfaults.ThethreefaultsystemsidentifiedintheMontTerrirocklaboratorycanbeintegratedintothesurroundingmap-scalestructuresinacoherentway.

ThedevelopmentandgeometryofEDZfracturenetworkdependlargelyontheexcavationdirectioninrespectwiththepre-existingfaults.Tunnelorientationinrespectwiththebeddingseemstoplayanimportantroleduetotherockanisotropy.Whenthedriftexcavationisnormaltothebeddingandfaultsplanesdippingwith45°toSSE,thechancetoinitiateEDZfracturesisquitelimitedsincetherockanisotropystructureisperfectlyorientedintheCoulombcriteriafailuredirection.Theseweaknessplanesarereactivatedasshearfractures.SecondaryEDZfracturesmaydevelopbelowthesefaultplanes.Inturn,insectionswherefaultsarescarce,whatevertheexcavationdirection,well-developedEDZfracturenetworkisobserved.However,Dependingonthefacieswhichisexcavated,theoccurrenceofEDZfracturesmaysignificantlychange.Infact,theOpalinusClayintheMontTerrirocklaboratorymaybedividedintothreemainfacies:ashalyfaciesinthelowerpartoftheformation(argillaceousandmarlyshaleswithmicasandnodular,bioturbatedlayersofmarlsorwithmm-thicklayersofsandstones),asandyfaciesinthemiddleandupperpartoftheformation(marlyshaleswithlayersofsandstonesandbio-turbatedlimestones,orwithlensesofgrey,sandylimestonesandmm-thicklayersofwhitesandstoneswithpyrite;andathincarbonate-rich,sandyfaciesinthemiddleoftheformation(calcareoussandstonesintercalatedwithbioturbatedlime-stonebeds,thelattershowingahighdetritalquartzcontent).Thesefaciesarecharacterisedbydifferentuniaxialcompres-sivestrengths.Theshalyfaciespresentsthelowervaluesofstrengths,10.5MPaparalleltothebeddingand25.6MPanormaltothebedding.Thismaybeareasontoexplaintheoccurrenceofwell-developedEDZfracturenetworkingallerysectionexcavatedthroughtheshalyfacies.Inturn,EDZfracturesinthesandyfacies,characterisedbyanaveragevalueofuniaxialcompressivestrengthof35MPa,areveryscarce.

Inconclusion,thepre-existingnaturaldiscontinuitiessuchaswelldeveloped,inclinedbeddingplanesandfaults,seemtoactaslimitingstructures(Figure1).Mechanicalcharacteristicsofthefacieswhichareexcavatedalsoinfluencethegenera-tionofEDZfractures.

Figure1.Relationshipbetweenalowanglenaturalthrustfault(upper)whichlimitsasetofsubverticalextensionalEDZfracturescharac-

terisedbyplumosestructures(Photo:Comet,PhotoshoppingZürich)

REFERENCESNussbaum,Ch.andBossart,P.Geology.InMontTerriRockLaboratory.Project,Programme1996to2007andResults.(2008).

Ed:Bossart,P.&Thury,M.:–Rep.SwissGeol.Surv.3.

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s 2.43

Transition from frictional to viscous deformation in granitoid fault gouges

PečMatěj*,StünitzHolger**,HeilbronnerRenée*

*Geologisch-Paläontologisches Institut, Bernoullistrasse 32, CH-4056 Basel (matej.pec@unibas.ch)** Institutt for geologi, Universitetet i Tromsø, Dramsveien 201, 9037 Tromsø, Norway

Frictionalmovementonfaultsproducesextremelyfine-grainedfaultgougesandincreasesthepermeability,thusenablingfluidflow.Thefinegrainsize,togetherwiththepresenceoffluids,isapotentialprecursorforthetransitionfromfrictionaltoviscousdeformationinthefaultgouge.

Inordertoinvestigatethisswitchinthedominantdeformationmechanism,weperformedaseriesofsimplesheardeforma-tionexperimentsinaGriggsdeformationapparatus.CrushedVerzascaGneisspowder (grainsize<200µm)with0.2wt%wateraddedwasplacedbetweenforcingblockscutat45°andweld-sealedingoldandplatinumjackets.Alltheexperimentswererunat500MPaconfiningpressureand300°Cor500°C.

Thefinegrainsizeisproducedduringthefirstpartoftheexperimentsbyfastdeformation(strainrate=10-4and10-3s-1)toagamma-valueofupto2.5.Thematerialconsistsofafine-grainedgougewithaporosityofaround1%.Angular,extremelyfine-grainedparticles(<50nminsize)aredistributedthroughouttheshearzone.Theamountoffine-grainedmaterialin-creasestowardsshearbandsthatdevelopatlowanglestotheshearzoneboundary.

Inthesecondpartoftheexperimentswestoppedthedeformationatpeakdifferentialstressandallowedthestressestorelaxoveroneweek(caseA).Alternatively,weloweredthepeakdifferentialstresstoalevelclosetotheconfiningpressureandkeptitconstantforoneweek(caseB).

IncaseAexperiments,weobserveslow(creep)strainrates(aslowas10-8sec-1)andatemperaturedependenceofthecreeprate.Thestressdropofsamplesdeformedat500°Cislarger(~200MPa)andthedisplacementishigher(0.141mm)comparedtothesamplesdeformedat300°C(80MPaand0.110mm,respectively).IncaseB,theamountofdisplacementaccommoda-tedbythesamplesisfarsmaller(total0.01mmat500°C),itisatthelimitofmeasurementsthatcanberesolvedwithourcurrentapparatus.

ThemicrostructuresinbothcaseAandBexperiments(fig.1)arestrikinglydifferentfromthosedeformedbyfrictiononly(fig.2).Weobservethedisappearanceofthefinestgrainsizefraction,appearanceoflobateinterconnectedgrainboundariesandthecementationofmultiplegrainsintobiggerones.

Fromtheseobservations,togetherwiththeobservedtemperaturedependence,weinferthatthesamplesweredeformedbysolution–precipitation-creepprocesses.Theexactnatureofthecreepdeformationisdifficulttoassessatthisstage,becau-sethestresslevelsnecessarytoachievecreepintheexperiments,sofar,areabovetheGoetzecriterion.

Figure1:Faultgougedeformedbycreep

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Figure2:Faultgougedeformedbyfrictiononly

2.44

Structural observations from the Insubric fault between the Valle d’Ossola and Valle d’Orco (NW Italy)

PleugerJan*&MancktelowNeil*

*Geologisches Institut, ETH Zürich, Sonneggstraße 5, CH-8092 Zürich

ThePalaeogenetoMioceneInsubricfaultzone(IFZ)separatestheSouthAlpinedomainfromunitsthathavebeensubductedduringAlpineorogeny.FromValled’OssolatosomewhatNofSerrad’Ivrea,theSouthernAlpsaretypicallyrepresentedbythe Ivrea zone and the adjacentNWblock by the Sesia zone. Further SW, the IFZ splits into the Internal and ExternalCanavesefaults(ICFandECF).TheCanvesezones.str.occupiesthepositionbetweentheECFandICFandthusbetweentheSesiaandIvreazones.CarbonaticlensesoccuringsporadicallyfurtherNEarereferredtoasCanaveses.l..TheverticaldisplacementalongtheIFZvariesalongstrikeandislargestSoftheLepontinedome.Thehorizontaldisplace-mentisestimatedasca.30kmbyMülleretal.(2001)andca.100kmbySchmid&Kissling(2004).TheIFZrocksshowspatialandtemporalvariationsindisplacementsenseanddirectionandofmetamorphicconditionsduringmovement.OurobservationsfromValled’OssolalargelyagreewiththoseofSchmidetal.(1987).TheIFZisaseveralhundredmetresthick,moderatelytosteeplyNW-dippinggreenschist-faciesmylonitezone,mostlywithaNW-side-upshearsense.TheNW-side-upmylonitesareanaxial-planarfoliationS

1ofafirstInsubricfoldgenerationF

1.InthesouthernpartoftheIFZ,F

1and

S1areoverprintedbyasecondfoldgenerationF

2.ComingfromtheNW,F

2firstappearswithaxesthatareparalleltoagent-

lyNE-plungingintersectionlineationbetweenS1andtheF

2axial-planarfoliationS

2.AstheintensityofD

2increasestoward

theSE,thelineationclearlybecomesastretchinglineation,theorientationplungesmoresteeplyNE,andisassociatedwithaSE-side-upanddextralshearsense.FurtherSWinValleStronaandValleMastallone,thevolumeofSE-side-upmylonitesexceedsthatofNW-side-upmylonites.InValleStrona,theNW-side-upmylonitesaremoreinternal(SE)withrespecttotheSE-side-upmylonitescontrarytowhatisobservedinValled’OssolaandValleMastallonewherethelatteraremainlyconfinedtomylonitesderivedfromanIvreazoneprotolith.InValleMastallone,twogenerationsofSE-side-upmylonitesexist.Theoldergeneration,foundnearRimella,hasaNE-SW-trendingstretchinglineationandadextralplussouth-side-upshearsense.Thedominantyoungergenerationhasanapproximatelydown-dip(NW)orientationofthestretchinglineation.TheseSE-side-upmylonitesarelocallyoverprintedbysmall-scaleductiletobrittle,gentlyS-dipping,faultzoneswithaSE-directednormalsenseofmovement,andbyaNNE-SSW-trendingandsteeplydippingsinistralmylonitictocataclasticfaultzonenearFobello.StillfurtherSWinValleSessera,cataclasticInsubricdeformationbecomesdominantoverductileshearingintermsoftheaffected rock volumes. The SouthAlpine rocks are locally affectedby lower greenschist-faciesmylonite zones. These aremostlyonlyafewmetresthickandbothdextralandsinistraldisplacementsensesareobserved.Themostcharacteristicca-taclasiteconsistsofaseveraltensofmetresthickbrecciawithquartz-richmylonitefragments.Thismyloniteiseithercom-

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s pletelyreworkedinthebrecciaorstillpreservedbelowtheEarlyOligoceneandesitesthatareexposedbetweenthebrecciaandtheSesiazone.TheandesitesoccuralongtheIFZfromValleSesseratotheS,untilclosetotheSerrad’Ivrea.Itisnote-worthythatbasementxenolithswithintheandesitesareexclusivelyderivedfromtheSesiazone,whichimpliesupliftoftheSouthernAlpsrelativetotheSesiazoneafterandesitedeposition.ThebrecciaimmediatelySEoftheandesitesandthekaki-ritesbetweenthebrecciaandIvreazoneprobablydevelopedduringthisuplift.SoftheSerrad’Ivrea,deformationalongtheECFandICFwasmostlybrittle.AttheECF,onlyrocksthatcandeformductile-lyunderrelativelylowtemperatures,suchascalcschistandserpentinite,weremylonitised.SuchmylonitesgenerallyreflectW-side-up faultingwithnegligiblehorizontal components. Strike-slip faultingwasmostlyaccommodatedby laterbrittlefaultingalongtheECF.Whilethedisplacementsenseofstrike-slipmotionsalongtheECFisambiguous,thebrittletobrittle-ductilefaultrocksoftheICFconsistentlyshowcombinedE-side-upanddextraldisplacement.Thekinematicvariationsalong-strikeandacrosstheIFZmaybeintegratedintothefollowingsimplifiedpattern.VerticalmotionsprevailedearlierintheIFZhistorywhilestrike-slipdisplacementbecamelatermoreimportant.Thecombineddis-placementalongtheECFandICFresultedinaloweringoftheCanavesezones.str.withrespecttoboththeSesiaandIvreazones.NEofSerrad’Ivrea,thisloweringresultedinthedownwarddisappearenceoftheCanavesezone,exceptforthespo-radiccarbonaticlensesofCanaveses.l..AcrosstheIFZ,thedifferenceinmetamorphicgradeoffaultrocksderivedfromtheSesiaandIvreazonesappearsmoderate.Therefore,thenetverticaldisplacementbetweenthetwo,resultingfromthecom-binationofNW-side-upandSE-side-upfaulting,wasprobablyalsomoderate.Alargepartoftheexhumationofthehigh-temperaturemetamorphicrocksoftheLepontinedomemayinfactberelatedtoupdominginthecoreoftheVanzonean-tiform,ratherthanbackthrustingalongtheIFZ.Theamountofstrike-slipdisplacementincreasesfromSWtoNE.Whileitis unclear if sinistral or dextral shearing prevailed in the Canavese, in Valle d’Ossola only dextralmylonites are found(thoughwithvaryinghorizontalcomponents).ConsideringthatthedominantD

1N-side-upmylonitesexposedthereformed

entirelyundergreenschist-facies conditions,without any synkinematic transition fromhigheror to lowermetamorphicgrade,thehorizontaldisplacementoftheD

1andD

2mylonitesisunlikelytoexceedafewtensofkilometres.

REFERENCESMüller,W.,Prosser,G.,Mancktelow,N.S.,Villa,I.M.,Kelley,S.P.,Viola,G.&Oberli,F.2001:Geochronologicalconstraintson

theevolutionofthePeriadriaticFaultSystem(Alps).Int.J.EarthSci.,90,623-653.SchmidS.M.&Kissling,E. 2000:Thearcof thewesternAlps in the lightofgeophysicaldataondeepcrustal structure.

Tectonics,19,62-85.SchmidS.M.,Zingg,A.&Handy,M.1987:ThekinematicsofmovementsalongtheInsubricLineandtheemplacementof

theIvreaZone.Tectonophysics,135,47-66.

2.45

Apatite FT data from the Triassic Songpan-Garzê flysch, Tibetan Plateau, NW Sichuan, China

RahnMeinert*&WangHejing**

*ENSI, 5232 Villigen-ENSI, Switzerland (meinert.rahn@ensi.ch)**School of Earth and Space Sciences, Peking University, Beijing 100871, P. R. China

TriassicflyschesoftheSongpan-GarzêorogeninSichuan,CentralChina,coveranareaof5timesthesizeofSwitzerland.OutcropsarelocatedintheeasternmostTibetanPlateau,borderedtothewestbytheLongmenshanfault,siteofthe2008Wenchuanearthquake(Haoetal.2009)Accumulatedflyschsedimentsreachthicknessesof15kmandhaveundergoneup-perdiageneticto lowermostgreenschist faciesconditionssoonafterdeposition.Themetamorphicandlaterexhumationhistoryoftheflyscheswasinvestigatedbymeansofillitecrystallinity(IC)e.g.Wangetal.2008)andapatitefissiontrack(FT)dating,withonesampleprofileextendingacrosstheLongmenshanfaultsystemintotheSichuanbasin.

48apatiteFTsamplescoveranagerangebetween3and136Ma,suggestingthatallsamplesareatleastpartiallyannealed(theyoungestdatedsedimentsareJurassic).AmarkedcorrelationbetweenICandFTdatarevealthatthedifferencesinre-cordedmetamorphicgradeatthepresent-daysurfaceweresignificantlycausedbydifferentialexhumation,i.e.thestructu-ralevolutionoftheformerflyschbasin.OnesamplegroupofLateMioceneFTageswithintheflyschcoincideswitharegi-onalincreaseinmetamorphicgradeuptogreenschistfaciesconditions.

Verticalprofileswereinvestigatedtostudythetectono-thermalstructureoftheflyschesduringmetamorphismandexhu-

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icsmation.Oneverticalprofile(2400-4100m)showsalineartrendcorrespondingtoaFTagegradientof42myrperkmaltitude.

Regardingitstracklengthandillitecrystallinitydata,theprofilepatternisrecognizedasthelowerpartofanexhumedpartialannealingzone.Thelowerendofthepartialannealingzoneisestimatedatappr.15Ma,corroboratedbythepresen-ceofsimilaragesfurtherN.Fromtheverticalthicknessofthepartialannealingzone(>3km),thethermalgradientduringapatiteageresetmusthavebeen<20°/km.

TwosamplegroupswithresetLateMiocenetoPlioceneapatiteFTagesnexttofaultsoftheLongmenshanfaultsystemcon-firmverticaloffsetoftheeasternsideblocksbytectonicactivity.Areasofstrongdifferentialupliftcontrastwiththelocalityofthe2008Wenchuanearthquakealongthemainfaultline.Youngupliftisherefoundfurtherwestofthemainfault,wherealsoaseriesofformerearthquakesofslightlylowermagnitudewasrecordedinthepast.

REFERENCESHaoK.X.,Si,H.,Fujiwara,H.&OzawaT.2009:Coseismicsurface-rupturesandcrustaldeformationsofthe2008Wenchuan

earthquakeMw7.9,China,GeophysicalResearchLetters,doi:10.1029/2009GL037971.Wang,H.,Rahn,M.,Tao,X.,Zheng,N.,Xu,T.2008:DiagenesisandmetamorphismofTriassicFlyschalongprofileZoige-

Lushan,NorthwestSichuan,China.ActaGeologicaSinica82,917–926.

2.46

Dynamic Topography Determination of the Western Mediterranean Sea from Jason-1 Data

RamiAli*,KahloucheSalem*,KhelifMhamed**

(*) Centre of Space Techniques, PO Box 13, Arzew 31200 Oran Algeria (rami_alidz@yahoo.fr)(**) Abou Bakr Belkaid University, Faculty of Science Engineering 13000 Tlemcen Algeria

Theoceanhasamajor impactonearthly lifeanddomesticneeds; theemergenceof satellitealtimetryallowsusa largecontributionformostapplicationsandoceanographicactivities. Inparticular, theseadynamictopography,which is thedistanceseparatesthegeoidandtheseasurfaceheightandthatreflectsthedynamicsoftheocean,isaprimordialoceano-graphyunknown.

Theprocessingofjason-1satellitedatapermitustodeterminatetheMediterraneansurfaceheight,whileusingtheglobalmodelofgeoid “EGM2008”obtained fromacombineddata (GRACE,Terrestrial andaltimetricmeasurements,….)wecancalculatetheseadynamictopography.

ThecomparisonoftheobtainedresultswiththedatatransmittedinthemessageofJason-1satelliteallowedusthevalida-tionofthemethodologicalapproachdeveloped.

REFERENCESDarwin,G.H.(1883).ReportontheHarmonicAnalysisofTidalObservation,Brit.Ass.forAdv.Sci.Rep.Kahlouche,S.,A.Rami,S.A.BenAhmedDaho(2003).TopexAltimetricMeanSeaLevelandGravimetricGeoidintheNorthof

Algeria,InternationalAssociationofGeodesySymposia,SpringerVerlag126,PP….–ISSN0939-9585.Lefevre,F.(2000).Modélisationdesmaréesocéaniquesàl’échelleglobale:assimilationdedonnéesinsituetaltimétriques,

Thèsed’état.Newton,I.(1687).PhilosophiaeNaturalisPrincipiaMathematica,London.Rami, A., Khelif,M., Kahlouche, S., Dennoukri., T. (2006). Estimation of the Sea State Bias Effect on theAltimetric

MeasurementsUsingaParametricModel, In:ProcoftheSymposium15thYearsofProgress inRadarAtimetry,SP-614ESAPublicationDivision–ISBN92-9092-925-1–ISSN1609-042X.

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s 2.47

Mirror denudation pattern on both sides of the Central Atlantic – a trace of the Pangea break-up?

RuizGeoffrey*,SebtiSamira**,SaddiqiOmar**,NegroFrançois*,StuartFin***,FoekenJurgen****,StockliDani*****,FrizonDeLamotteDominique******

* IGH,E.Argand11,CH-2009Neuchatel(geoffrey.ruiz@unine.ch)** FacultédesSciences,AinChock,Casablanca-Morocco*** SUERC,Glasgow-UK**** FALW,VrijeUniversiteitAmsterdam-NL***** DptofGeology,Uni.Kansas-USA****** Uni.Cergy-Pontoise-France

ThetargetareaofthisprojectistheWSW-ENEorientedintra-continentalAtlaschaininMoroccolocatedbetweentheWestAfricaCratonandtheBetic-Rifsystem.Itisakeynaturallaboratorybecauseit1)isthesouthernmostexpressionofAlpinedeformation inAfrica,and2)encompassesPre-Cambriantorecentevolutionof theregion.ThepresenceofhighsurfaceelevationstodayintheHigh-Atlas(>4000m)andAnti-Atlas(>2500m)tothesouthissubjecttodiscussionsbecausethereislittlequantitativedataavailableatpresent.Phasesofupliftarethusillconstrainedasplaceswheretheassociatederosionproductswereaccumulated. TobetterconstrainthemostrecentorogenicgrowthoftheAtlaschain,weselectedasectionlocatedtotheSWofMorocco,andinvestigatedthetime-Temperaturepathsfromthedifferentmorpho-structuraldomainsusinglow-tempera-ture thermochronology analyses. These are Fission-Track analysis on Apatite (120-60°C), Zircon (270-210°C) and U-Th/Heanalysis stillonApatite (80-45°C)andZircon (200-170°C)minerals.Resultsaremuchcontrasted fromonedomain to theother:Pre-CambrianbedrocksfromtheAnti-AtlasdomainyieldoldthermochronologicalFission-Trackagesonzircon(380-300Ma)andapatite(180-120Ma)mineralsthatareassociatedwithslightlyyounger(U-Th)/Heagesonapatite(150-110Ma).U-Th/HeagesonapatitefromtheHigh-Atlasaremuchyounger(~35-5Ma)withaclearalpinesignature.ApatiteFission-TrackagesfromtheMesetaregionfurthernortharealsorelativelyoldrangingbetween200and140Ma. WehereconcentrateontheinterpretationofoldthermochronologicalagesfromtheMesetaandAnti-Atlasregionsleaving theAlpine signal foranothercontribution.Thereare twodirect,possibly inter fingering, interpretations for thepreservationofsucholdthermalrecordintheAnti-AtlasandMesetaregions.Firsttheyremained“stable”beingunaffectedby'Alpine'deformationthattookplaceintheHigh-Atlas.Second,theyarebeingaffected“now”butnolevelwithsuchrecordisyetexposed.Thermalmodellingwasperformedtodecipherbetweenthe2scenariosusingournewthermochronologicalandavailablegeologicalconstraints.ModelssuggestthatthefirstscenarioismostlikelywithaclearTriassictoLateJurassicphaseofheatinguntil~100-90°CthatwasfollowedbyaphaseofcoolinguntiltheMiddleCretaceous.TheseresultssuggestthattheMesetawasburiedbya2-3kilometresthicksedimentarypileuntil~180MaandasaresultthattheconceptofatopographichighlimitingtheTethysianfromtheAtlantichastobereconsidered.Further,denudationpatternsfromthemirrorimageoftheAtlassystemontheothersideoftheAtlanticoceanarealmostidentical(GristandZentilli,2003)sug-gestingthatthepatternsweconstrainedfortheTriassicuntilMiddleCretaceousinSWMoroccohavetoberelatedtothebreak-upofthePangeaandoceanizationintheCentralAtlanticfrom~180Ma.

REFERENCESGrist,A.M.,&Zentilli,M.(2003).Post-PaleoceneCoolingintheSouthernCanadianAtlanticRegion:EvidencefromApatite

FissionTrackModels.CanadianJournalofEarhSciences,40(9),1279-1297.

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The Eastern Pelagonian metamorphic core complex (northern Greece): Structure and models

SchenkerFilippoLuca*,BurgJean-Pierre,GeryaTaras.

ETHZ, Department of Earth sciences, Sonneggstrasse 5, CH-8092 Zürich*(filippo.schenker@erdw.ethz.ch)

GeologicalmappingrevealedamigmatiticdomeinthefootwallofalowangledetachmentintheeasternPelagonianregion,tothenorthandeastoftheAliakmonRiverartificiallake,inGreece.Thedomedimensionsareabout20x15kmwiththelongaxisstrikingNNW-SSE.AlllithologiesshowapenetrativefoliationstrikingmainlyNW-SEanddippingNEorSW,accord-ing to thedome flank.On the foliationplaneaNE-SWstretching lineation is associatedwith senseof shear indicators.Systematicmeasurementsaverageasfollows:i)Top-to-the-SWsenseofshear:Direction:254°±15;Plunge:12°±9,ii)Top-to-the-NEsenseofshear:Direction:47°±17;Plunge:15°±13.Whilethetop-to-the-SWsenseofshearisregional,top-to-the-NEshearreferstorelativelynarrow(20to100m)shearzones.Themostspectacularoftheseshearzonesjuxtaposeshighlymigmatiticorthogneissesagainstnonmigmatiticones.Inthemigmatiticcorebothbiotiteorthogneissesandamphibolites(formerbasalticdykesthathaveintrudedintothecrystallinebasement)haveundergonepartialmelting.Meltingofthemetagranitelocallyproducedgarnet+amphibole+melt,whichwouldindicatePressure-temperatureconditionsof10-20kband<800-900°Crespectivelyunderwater-saturatedconditions.ZirconU-Pbdatingfromamigmatiteonthenorthwesternflankofthedomesuggeststhatmeltingtookplaceat137±1Ma[Anders,2007].Theresultswerethebasisfornumericalmodellingofmigmatitedomesinextensionalsetting.WeemployedI2ELVIS,anu-merical 2D computer code designed for visco-elasto-plastic rheology and using conservative finite differences method[Gerya,2003a].Themodeldomainis300kmwideand160kmdeep.Itconsistsoffourrheologicallayersrepresentinguppercrust, lower crust, lithosphericmantle and asthenosphericmantle. Changing parameters as extension rate, lithospherethicknessandgeothermspointstotheimportanceofpartialmeltinginthelowercrustal:(1)itmaintainsaflatMohoand(2)positivebuoyancyofmolten rocksenhancesdoming.PTtpathsofmodelpointsareused todiscriminate thermo-me-chanicalscenariofmigmatiticcorecomplexes.

REFERENCESAnders,B.,Reischmann,T.&Kostopoulos,D. 2007:Zircongeochronologyofbasement rocks from thePelagonianZone,

Greece:constraintsonthepre-AlpineevolutionofthewesternmostInternalHellenides,IntJEarthSci(GeolRundsch),96,639-661.

Gerya,T.V.&Yuen,D.A.2003a:Characteristics-basedmarker-in-cellmethodwithconservativefinite-differencesschemesformodelinggeologicalflowswithstronglyvariabletransportproprieties.PhysicsoftheEarthandPlanetaryInteriors,140,295-320.

2.49

Formation of fold nappes in ductile multilayers: insights from numerical simulations

SchmalholzStefanMarkus

ETH Zurich, Geologisches Institut, Sonneggstrasse 5, CH-8032 Zurich (schmalholz@erdw.ethz.ch)

Foldnappesarelarge-scalerecumbantfoldsthathavemostlikelyformedbydominantlyductiledeformation.IntheWesternSwissAlps,theMiddleandLowerPenninicbasementnappesaswellastheHelveticonesdisplay,inmostcases,thetypicalgeometryandstratigraphyoffoldnappeswithanormalflank,afrontalpartandanoverturnedlimb(Escheretal.,1993).Incontrasttofoldnappes,thrustsheetslackanoverturnedlimbandarecharacterisedbyabasalthrustordetachmentsurface(e.g.EpardandEscher,1996).IntheSwissAlps,thecoreoffoldnappesoftenconsistsofmetamorphicbasementsurroundedbyasedimentarycover(e.g.Escheretal.,1993;EpardandEscher,1996).ExamplesaretheMorcle-Mont-BlancnappeortheAntigorionappe(e.g.Escheretal.,1993).AlthoughfoldnappesarefrequentintheSwissAlpsandareaprominentfeatureinmanymountainbelts,thereareonlyfewstudiesthatinvestigatedthemechanicaldeformationprocessesactingduring

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s theformationoffoldnappes.Therefore,therearestillmanyopenquestionsconcerningthecontrollingfar-fielddeformati-onfield(simpleorpureshear),therheology(e.g.Newtonianviscous,power-laworviscoplastic)andtheimpactofhetero-geneities(e.g.effectiveviscosityratiowithinsedimentarycover).Ipresentfirstresultsoffiniteelementmodelssimulatingtheformationoffoldnappesinductilemultilayers.Inthesemo-delsthesedimentarycoverismodelledwithductilemultilayersexhibitingapower-lawrheologyandthebasementismo-delledwithonethicklayerhavingalsoapower-lawrheology.Thefar-fielddeformationfieldisassumedtobesimple-shear.TheappliedfiniteelementmethodemploysaLagrangianformulationwithre-meshingwherethenumericalgridisdefor-medwiththecalculatedvelocityfield.Thismethodensuresthattheboundariesbetweenthedifferentlayers(i.e.sedimen-taryunitsandbasement)areaccuratelyresolvedduringtheentirelargestraindeformation.Figure1presentstheresultofoneparticularsimulation.Althoughthemodelisrelativelysimpletheresultsalreadyshowseveralinterestingfeatures:a)thesedimentarylayersaredetachedfromthebasementatseverallocations,b)foldsofdiffe-rentsizeandorderareformed,c)foldaxialplaneswithdifferentorientationsareformedduringonecontinuousdeforma-tionphaseandd)recumbentfoldswithoverturnedlimbsmoreorlessparalleltothefar-fieldsimplesheardirectionareformed.Furthermore, inthemiddleof themodel themultilayers formeda foldnappewhichhasanoverturned limb,afrontalpartandanormallimb.TheapplicabilityofthepresentednumericalmodelstonaturalfoldnappesintheSwissAlpsisdiscussed.Also,modellingapproachesforamorerealisticnumericalmodellingoffoldnappesintheSwissAlpsarepresented.

Figure1.Numericalresultformultilayerfoldingunderfar-fieldsimpleshear.A)Initialgeometry.B)Geometryforashearstrainof2.8.

REFERENCESEscher,A.,Masson,H.&Steck,A.1993:NappegeometryintheWesternSwissAlps,J.Struct.Geol.,15,501-509.Epard,J.-L.&Escher,A.1996:Transitionfrombasementtocover:ageometricmodel,J.Struct.Geol.,18,533-548.

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Two critical tapers in a single wedge

JeroenSmit*,Jean-PierreBurg*andJean-PierreBrun**

*ETH Zurich, Geological Institute, Sonneggstrasse 5, 8092 Zurich** Géosciences Rennes, Université de Rennes 1, Campus de Beaulieu, Bat 15, 35042 Rennes, France

Thrustinvolvingaductiledécollement(e.g.salt,over-pressuredshales)likeZagros,Jura,PakistanSaltRanges,CascadesandMakranhave incommonasmallcross-sectional taper,attributedto largethrustspacingandfast frontwardpropagationabovetheductiledécollement.Suchalowcross-sectionaltaperhasbeenanalyticallyexplainedbyapproximatingtheductilelayerasahorizonwithnegligibleshearstrength.Wetestedthedevelopmentofthrustwedgesinvolvingaductilebasaldécollementofuniformshearstrengthbymeansoflaboratoryexperiments.Themodelconsistsofasandlayerwithinitialwedgegeometryandabasalductiledécollementofconstantthicknessandshearstrengthmadeofsiliconeputty.30%ofbulkshorteningisappliedtothewedgeatconstantvelocity.Thrustingstartsinthemiddleofthewedge,followedbyin-sequencefrontwardpropagation.Thebackpartofthewedge,betweenbackstopandtheclosestthrust,remainsundeformed;itpassivelyadvancesoverthebasewithoutinternaldeformation.Itappearsthatbothdomainshavedifferentcriticaltapers.Theinnerdomainisinacriticalstatefromtheonsetofshorte-ning(i.e.theinitialwedgeisalreadycritical),whilethefrontaldomainsteadilyacquiresastateofcriticaltaperbythrusting.Thisresultisatvariancewiththeclassicalassumptionthatshorteningofawedgemadeofhomogeneouslayerscreatesasinglecriticaltaper.Theexperimentalthrustwedgesdoshowotherfeaturescharacteristicforweakdécollementwedgeslikenarrowcross-sectional taper, large thrust spacingandvariety in thrustgeometries.Applicationof the results tonaturalthrustwedgesliketheJuraMountainscouldshednewlightontheirdevelopmentandgeometryatdepth.

2.51

Modelling the thermo-chemical evolution of the interiors of Mercury, Venus, Earth, Mars and super-Earths

TackleyPaul,KellerTobias,ArmannMarina,vanHeckHein,NakagawaTakashi

Institut für Geophysik, ETH Zürich, Sonneggstrasse 5, 8092 Zürich (ptackley@ethz.ch)

Thelatestgenerationoftheglobal3-DsphericalconvectionmodelStagYY[Tackley,PEPI2008]allowsthedirectcomputationofaplanet's thermo-chemicalevolution, including self-consistent lithosphericbehavior (e.g., rigid lid,plate tectonics,orepisodicplatetectonics[vanHeckandTackley,GRL2008]),chemicaldifferentiationinducedbymelting,largeviscosityvari-ations,aparameterizedcoreheatbalance,andarealistictreatmentofphasediagramsandmaterialproperties.Thelatterhasrecentlybeenaddedusingfreeenergyminimizationtocomputestablephasesasafunctionoftemperature,pressure,andcompositionasexpressedbyratiosofthefivemainoxides,andthusavoidstheneedforincreasinglycomplicatedandadhocparameterizationsofphasetransitions.Globalmodelsallowthecomputationofplanetarysecularcoolingincludingpredictionofhowthecoreheatfluxvarieswithtimehencetheevolutionofthegeodynamo,andpossibletransitionsinplatetectonicmode.Modernsupercomputersandclustersallowincreasinglyhigherresolution,withupto1.2billionunknownspossibleononly32dual-processornodesofanopteroncluster.Inongoingresearch,thistoolisbeingappliedtounderstandtheevolutionofEarth,Mars,Venus,Mercury,andsuper-Earths.Studyingseveralbodiesusinganintegratedapproachfacili-tatesamoresystematicandholisticunderstandingofplanetarybehaviourbothinsideandoutsideoursolarsystem.

OurMarsmodels[T.KellerandP.J.Tackley,Icarus2009]showthatwithanappropriateviscosityprofile,convectionrapidlydevelopsa'oneridge'planformconsistingofasingleridge-likeupwellingandsmall-scaledownwellingsbelowastagnantlid,andthatthisproducesadichotomouscrustaldistributionthatbearsastrikingfirst-orderresemblancetothecrustaldistri-butiononMars.TheactualboundaryofthecrustaldichotomyonMarsisnothemisphericalbutratherliketheseamonatennisball,andthisisreproducedbyourmodels,withthehighlandregionbeinglocatedabovetheupwelling.Furthermore,theelevationdifferencebetweenthehighlandandlowlandregionsisverysimilartothatonMars,althoughtheaveragecrustal thickness ishigher than thought tobeappropriate forMars. In somecalculations, the locationof theupwellingsubsequentlymigratestotheedgeofthehighlandregion,providinganexplanationforTharsis.Meltingisfoundtohaveadramaticinfluenceonthermalevolutionparticularlyduringtheearlystages.

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s WithourVenusmodelswearestudingthemodesofheatloss,theoriginoftheinferredsurfaceageandunderstandingtheadmittance(gravity/topography)ratio.Ofparticularinterestiswhetherasmoothevolutioncansatisfythevariousobserva-tional constraints, orwhether episodic or catastrophic behaviour is needed, as has beenhypothesised by some authors.Simulationsinwhichthelithosphereremainsstagnantovertheentirehistoryindicatethatovertime,thecrustbecomesatleastasthickasthemechanicallithosphere,anddelaminationoccursfromitsbase.Thedominantheattransportmecha-nism ismagmatic.A thickcrust is aquite robust featureof these calculations.Highermantleviscosity results in largertopographic variations, thicker crust and lithosphereandhigher admittance ratios; tomatch thoseofVenus, theuppermantlereferenceviscosityisabout1020Pasandinternalconvectionisquitevigorous.Themostsuccessfulresultsinmatch-ingobservationsarethoseinwhichtheevolutionisepisodic,beinginstagnantlidmodeformostoftheevolutionbutwith2-3burstsofactivitycausedbylithosphericoverturn.Ifthelastburstofactivityoccurs~1Gabeforepresent,thenthepresentday tends todisplay lowmagmaticratesandmostlyconductiveheat transport,consistentwithobservations. Inongoingworkweareexaminingtheeffectofcrustalrheologyandamoreaccuratemeltingtreatment.

DuetotheabsenceofanatmosphereandproximitytotheSun,Mercury’ssurfacetemperaturevarieslaterallybyseveral100sK,evenwhenaveragedoverlongtimeperiods.Thedominantvariationintime-averagedsurfaceToccursfrompoletoequa-tor(~225K).Herewedemonstrate,usingmodelsofmantleconvectionina3-Dsphericalshell,thatthisstationarylateralvariationinsurfacetemperaturehasasmallbutsignificantinfluenceonmantleconvectionandonthelateralvariationofheatfluxacrossthecore-mantleboundary(CMB).Weevaluatethepossibleobservationalsignatureofthislaterally-varyingconvectionintermsofboundarytopography,stressdistribution,gravityandmomentofinertiatensor.InfutureweplantotestwhetherthelateralvariationinCMBfluxiscapableofdrivingathermalwinddynamo,i.e.,weakdynamoactionwithnointernally-drivencoreconvectivemotions.

Thediscoveryofextra-solarplanetswithterrestrialcompositionandsizesuptotwicethatofEarth,so-called"super-Earths",haspromptedinterestintheirpossiblemantledynamicsandevolution.Thepressureatthecore-mantleboundary(CMB)ofa2*Earth-sizedsuper-EarthisaboutfourtimesthepressureatEarth'sCMB,whichhasastrongeffectonphysicalpropertiessuchasthermalexpansivity,diffusivityandviscosity.Themantleofsuchasuper-Earthwouldbemademostlyofpost-per-ovskite(PPv),whichhasdifferentphysicalpropertiesthanperovskite,themajormineralofEarth'slowermantle.Hereweusethenewly-computedrheologicalparametersforPPv,computedusingdensityfunctiontheory[Ammann,BrodholtandDobson, 2008] in simulations of super-Earths ofup to twiceEarth size. Themodels assumea compressible anelastic ap-proximationthatincludesthedepth-dependenceofmaterialparameters.RheologicalparametersformineralsotherthanPPvarebasedonthoseforperovskite.Plasticyieldingatlowpressuresfacilitatesplate-likelithosphericbehaviour.Resultsdemonstratethatsuper-EarthsareequallylikelyormorelikelythananequivalentEarth-sizedplanettobeundergoingplatetectonics,andthatthe lowviscosityofPPvhasastrongandpreviouslyunseeneffectsonthemantledynamicsofsuper-Earths.

2.52

A numerical approach to test lithospheric cross-sections for geodynamic consistency

ThielmannMarcel*,KausBorisJ.P.*

*(2) Geophysical Fluid Dynamics, Department of Earth Sciences, Sonneggstrasse 5, ETH Zurich, Zurich,

Crosssectionsthoughactivemountainbeltsareusuallyconstrainedbyarangeofgeophysicalandgeologicaldata,buttheresultinginterpretationsarenotnecessarilygeodynamicallyconsistent.Tobetterunderstandthethermomechanicalbeha-viourofsuchcollisionzonesitisofmajorimportancetocombineknowledgeaboutthegeometrical,thedensityandtheinferredviscositystructureofthosezones.Constraintsonthegeometrycanbeobtainedbyreflectionseismics,refractionseismicsorseismictomography.Constraintsonthedensitycomefromgravimetricalmethods.Effectiverheologicalparame-tersofthelithosphere,however,aremuchlessknown.Laboratoryexperimentsoncreepofrocks,extrapolatedtonaturalconditions,yieldseveralordersofmagnitudevariationintheeffectiveviscosity.Betterconstrainingtheeffectiveviscosityofthe lithosphere ishowevercrucial, sincevariations in theseparametersmightresult indrasticallydifferent lithosphericdynamics.Forthisreason,weheredevelopandtestanapproachthatemploys2Dthermomechanicalviscoplasticgeodynamicscodes.Ratherthanstudyingthelong-termdeformationofthelithosphere,asistypicallydonewithsuchcodes,weherefocusonthepresent-daystructureofthelithosphere.Themainassumptionsare:1)thepresentdaygeometryofthelithosphere(inparticularsurfacetopographyandMohodepth)isreasonablywellknown.2)Far-fieldplatevelocitiesareknown(fromplatemodelsorGPSmeasurements). The lithosphere is thendivided into several layers.By varying the effective viscosity and

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icsdensityofeachofthelayers,wecanstudytheeffectsofchangingtheseparametersongravity,surfacevelocity,stress-distri-

bution,andmantleflow.Acomparisonofmodelleddatawithobservationswouldthus-inprinciple-givegeodynamicconstraintsontherheologyofthelithosphere.Beforeapplyingittorealdata,however,itisnecessarytostudythetheoreticalpowerofthemethodology.Forthisreasonwehereapplythemethodtosnapshotsobtainedfromsynthetic(million-yeartimescale)forwardruns.

2.53

Interaction of H2O rich fluid inclusions and natural quartz crystals in deformation experiments

ThustAnja*,HeilbronnerRenee*,StuenitzHolger**,TarantolaAlexandre***&HaraldBehrens****

*Geologisch-Paläontologisches Institut, Bernoullistrasse 32, CH-4056 Basel (anja.thust@unibas.ch)**Institutt for geologi, Universitetet i Tromsø, Dramsveien 201, N-9037 Tromsø*** Faculté des Sciences, Université Henri-Poincaré, 54506 Vandoeuvre-lès-Nancy, France****Institut für Mineralogie Universität Hannover, Callinstraße 3, D-30167 Hannover

TheeffectofH2Oonthestrengthofquartziswellknownandhasbeendiscussedmanytimesintheliteratur(e.g.Grigge&

Blacic1965,Kronenberg&Tullis1984,Kronenberg1994).HerewestudytheH2Ointeractionsbetweennaturaldryquartzand

H2Orich fluid inclusionsduringdeformation in thesolidmediumGriggsapparatus.Thedeformationexperiments took

placeunderarangeofconfiningpressures (700MPaupto1500MPa),mostlyat900°Candstrainratesof~10-6s-1.Wede-formedcylindersofsinglecrystalquartzthatwerecoredintwodifferentorientations(1)normaltooneoftheprismplanesand(2)45°to<a>and45°to<c>(O+orientation).Thestrengthsofthesamplesvaryfrom84MPaupto414MPa,withthemajoritybetween150MPaand220MPa.Lowstrengthcanbeexplainedbytheformationofnewlyrecrystallizedgrainsanddeformationbydislocationcreep,higherstrengthcorrelateswithalowerH

2Ocontentandlessdeformationofthesample.

TheH2Orichfluidinclusionscontaindifferentchlorideslikeantarticite(CaCl

2·6H

2O)andhydrohalite(NaCl·2H

2O),measured

withmicrothermometry;theyrangeinsizefrom50µmto700µm.Afterdeformationtheinclusionsaremorehomogene-ouslydistributedthroughoutthesampleanddramaticallyreducedinsize(<0.1µm).Regionswithalargechangeinsizeoffluid inclusionsare theregionswiththehighestconcentrationofdeformation (Fig.1).There isalsoadifference in fluidhomogenisationforthetwodifferentorientations.Incrystalswithorientationnormal{m},thefluiddistributionismorehomogeneousandtoafinerscalethanincrystalsofO+orientation.Afterdeformationthesalinityofthefluidinclusionsisincreased,from~10.6wt.%equivalentNaClupto~12wt.%equivalentNaCl.ThereleaseofH

2Ofromfluidinclusionsisanimportantprocessforcrystalplasticdeformation.Fluidinclusionrupture,

microcrackingandthefastcrackhealingatthesetemperaturespromotethedistributionofH2Othroughthequartzand

influencesthestrengthofthematerial.

Figure1:Deformedsampleinorientationnormalto{m}(seestereoplot),thelinesseparatethehighlydeformedpartinthemiddle,witha

highfluidinclusiondensityfromthe+/-undeformedpartattheends.

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The Lentas unit in Southern Crete: the base of the Pindos sedimentary series? – New paleontological results

VandelliAlessia*,VachardDaniel**,MartiniRossana***,KozurHeinzW.****,MoixPatrice*,StampfliGérardM.*

* Institut de Géologie et de Paléontologie, Université de Lausanne, Anthropole building, CH-1015 Lausanne (alessia.vandelli@unil.ch)** Université des Sciences et Technologies de Lille 1, F-59655 Villeneuve d’Ascq Cedex, France*** Département de Géologie et Paléontologie, Université de Genève, rue des Maraîchers 13, CH-1205 Genève**** Rézsü u. 83, H-1029 Budapest, Hungary

Creteisconstitutedbyacomplexnappestructure.Basedontheirtectonostratigraphicpositionandtheirtectonometamorphichistory,theseallochthonousunitsweresubdividedintotheupperandlowernappes,separatedbyadetachmentfault.InthestudiedareainsouthernCrete,onlytheuppernappesarerepresented. Inastructurallyascendingorder,theseare (1)theTripolitzaplatform,(2)thehemipelagictopelagicPindosdomain,(3)theArviunit,(4)theLentasseries,(5)theMiamoumé-lange,(6)themetamorphicAsteroussianappeand(7)theuppermostophioliticnappe(e.g.,Davi&Bonneau,1985).Thistecto-nicpilecouldactuallybepronetomodifications.OurpreliminaryresultsfocusontheLentasandthePindosunits(Fig.1).

IntheLentasseries,reworkedpebblesinaconglomerateaboveshallow-marinelimestonesyieldedthefirstoccurrenceoflateKungurian(latestEarlyPermian)foraminifersandcarbonatealgaeinGreece.Praelikanella cretaeVachard,Vandelli&Moixn.gen.,n.sp.andUragiellopsis bonneauiiVachard,Vandelli&Moixn.sp.arenewlyestablished.Theidentifiedassemblagebe-longstotheMisellina parvicostataZoneandhasaNorthPaleotethyansignature.Thepelagiclimestonesinterstratifiedwithsiltstones and turbiditic sandstones with plants yielded several conodonts species typical for the Lacian (early Norian) Epigondolella rigoiZoneandtheSevatian(lateNorian) Mockina bidentataZone.

InthepelagiclimestonesatthebaseofthePindosseries(Fig.1),weidentifiedLateTriassic(Carnian-Norian)foraminifersincluding Duostomina sp., Duotaxis sp., Endoteba ex gr. controversa Vachard & Razgallah, E. ex gr. obturata (Brönnimann &Zaninetti),Glomospirasp.,Ophthalmidiumspp.,Trochamminasp.,Glomospirasp.,MiliolidaeandNodosariidae.Inthesamesuc-cession,aconodontassemblagebelongingtotheMockina bidentataZonewassampled.

Our paleontological results in combinationwith field observations indicate a possible link between the Lentas and thePindossuccessions.BecauseofagesandfaciessimilaritieswithequivalentseriesinGreeceandTurkey,weproposethattheLentasseriesformsthebaseofthePindossequence.Furthermore,wesuggestthatthepelagiclimestonesofthePindosdo-mainareanequivalentoftheDrimosFm.,whilethepelagiclimestonesalternatingwithsandstonesandconglomeratesintheLentassequencecorrespondtothePriolithosFm.(cf.Degnan&Robertson,1998).TheseseriesbelongingtothepassivemarginofthePindosOceanarefoundallovertheeasternMediterraneanarea:thePindos-OlonosseriesinthePeloponneseandincontinentalGreece,theEthiaandMangassaseriesinCrete,theKöyceθizseriesintheLycianNappes,theHuθluseriesintheBeyθehir-HoyranNappesandtheMersinmélange(allinTurkey).Allofthesenappeslikelybelongtothesamepaleo-geographicdomain (Huθlu-PindosOcean,Moixetal.,2007). Inaddition,theshallowmarine lateKunguriansedimentsofPaleotethyanaffinityreworkedintheLentasunitiscompatiblewiththepresenceofreworkedpelagicFamennianconodontsatthebaseoftheMangassaseriesineasternCrete(Bonneau&Aubouin,1987).

Inconclusion,theLentasandPindosunitsbelongtothesamepaleogeographicrealmandrepresentthesynriftseriesandthedevelopmentofthepassivemarginoftheHuθlu-PindosOcean,aback-arcbasinofthePaleotethys.

REFERENCESBonneau,M.,Aubouin,J.,1987.DesfossilesdévoniensremaniésdansleTriassupérieurdelazoneduPindeenCrète(Grèce):

indicationssurlanaturedusubstratumanté-Permiendeszonehelléniquesexternes.C.R.Acad.Sc.Paris,t.304,SérieII,n°2Davi, E., Bonneau,M., 1985.Geologicalmap ofGreece, Andiskarion sheet 1:50000. Institute ofGeology andMineral

Exploration(IGME).Degnan,P.J.,RobertsonA.H.F.,1998.Mesozoic-EarlyTertiarypassivemarginevolutionofthePindosOcean(NWPeloponnese,

Greece).SedimentaryGeology117,33-70.Moix, P., Kozur,H.W., Stampfli,G.M.&Mostler,H., 2007.Newpalaeontological, biostratigraphic andpalaeogeographic

resultsfromtheTriassicoftheMersinMélange,SETurkey.In:Lucas,S.G.&Spielmann,J.A. (eds.).TheGlobalTriassic.NewMexicoMuseumofNaturalHistoryandScience,Bull.,41,282-311.

Vachard,D.,Vandelli,A.&Moix,P.,2009:DiscoveryofthelateKungurian(latestEarlyPermian)insouthernCrete(Greece);geologicalconsequences.Geobios(submitted).

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Triassic ?

Late Triassic

early to middle Eocene

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Carnian - Liassic

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Sevatian Mockina bidentata Zone

reworked Kungurian foraminifers and carbonate algae

Late Triassic foraminifers

NEW DATA

SIMPLIFIED STRATIGRAPHY

cherts sandstones and shalespelagic limestones platform limestonesHalobia-bearing limestones

polygenic conglomerates

Fig.1:SyntheticstratigraphiccolumnoftheLentasandPindosunits

2.55

Modelling of silicic intrusions in Alpine type orogens

VogtKatharina*,GeryaTaras*,**,CastroAntonio***

*Department of Earth Sciences, ETH Zürich, Sonneggstr. 5, 8092 Zürich, Switzerland(katharina.vogt@erdw.ethz.ch)**Department of Geology, Moscow State University, 119199 Moscow, Russia***Department of Geology, University of Huelva, 21071 Huelva, Spain

Theemplacementofhugeintrusivebodiessuchasbatholithsisafundamentalissueingeology.Toimproveourunderstan-dingofthedynamicsofbatholithemplacementsunderanactivecontinentalmargin,asetofnumericalexperimentshavebeenperformedusinga2Dgeochemical–petrological–thermomechanicalnumericalmodel.Basedonfinitedifferencesandmarkerincelltechniques,themodelsimulatessubductionofanoceanicplatebeneathanactivecontinentalmargin.Themodelincludesspontaneousslabretreatandbending,dehydrationofsubductedcrust,aqueousfluidtransport,partialmelting,meltextractionandmeltemplacement.Asystematicparameterstudyhasbeencarriedoutbyvaryingtherheologicalweakeningeffectimposedbyfluidsandmelts.Aqueousfluidspercolatingfromthesubductingslabintothemantlewedgemainlyaffecttheforearcregion,whereasex-tractedmeltspropagatingfromthemantlewedgetowardthesurfacehaveamajor impactonthe lithospherebelowthearc.Theresultsindicatethatseveraltectonicregimesexist,someofwhichshowthedevelopmentofsilicicplumes.Itwasfoundthattherheologicalweakeningeffectofmeltsandfluidsisofmajorimportancefortheformationandemplacementofsi-licicplumes.Asafunctionoffluidandmeltweakening,silicicplumesmay(1)ascendandintrudeintothecrust,(2)extendhorizontallyandremainbeneaththecontinentallithosphere(underplating)or(3)beemplacedatalaterstage.Strongfluidrelatedweakeningpromotesstackingofsedimentsandthereforeresultsinalargeaccretionwedge.Inthiscase,insufficientsedimentsarebeingsubductedandplumesdonotform.Smallamountsoffluidweakening,ontheotherhand,resultsinstrongcouplingofthesubductingandoverridingplatesinacollision-likesubductionsetting.Inthiscase,largequantitiesofsedimentsarebeingsubductedandsedimentaryplumesareformed.However,ifthecontinentallithosphereisinsuffici-entlyweakenedbyextractedmelts,thesesedimentaryplumescannotascend.Ourresultsthussuggestthatbatholithsmaybetheresultoftheemplacementofsilicicplumesintothecrustandtheiremplacementdynamicsisstronglyaffectedbytherheologicalweakeningeffectoffluidsandmelts.

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Influence of thermal-chemical buoyancy in 3-D mantle wedge

GuizhiZhu*,TarasV.Gerya*,**,SatoruHonda***,PaulTackley*,DavidA.Yuen****

*Department of Geoscience, Swiss Federal Institute of Technology (ETH Zurich), CH-8092 Zurich, Switzerland (guizhi.zhu@erdw.ethz.ch)**Adjunct Professor of Geology Department, Moscow State University, 119899 Moscow, Russia***Earthquake Research Institute, University of Tokyo, Tokyo 113-0032, Japan ****University of Minnesota, Minneapolis, MN 55455-0219,USA

Weuse 3-D petrological-thermomechanical numerical simulations to investigate hydrous, partiallymolten, cold plumesoriginatedfromthesubductingslab,whichisfavoredbythelowereddensityandweakenedrheologicalpropertiesoftheoverlyingmantlecausedbythefluidreleasefromthesubductingslab.

ThesimulationswerecarriedoutwiththeI3ELVIScode[Gerya,2009],whichisbasedonamulti-gridapproachcombinedwithmarker-in-cellmethodsandconservativefinite-differenceschemes.Thedynamicsofthepartiallymoltenplumesisinvesti-gatedinrheology-densityspaceoftheplumes,includingtheeffectiveviscosityofthepartiallymoltenrocksandthedensitycontrastduetocompositionaldifference.

Lowered viscosity of the partially molten rocks atop the subducting slab favors the development of the cold plumes.Indeed,theplumesof1019Pasviscosityaremorepowerfuloncetheplumesstartsincetheystartlaterandaccumulatemorebuoyancy than thoseof 1018Pa s viscosity.Moreover, thenotabledifference inplumebehaviors arisesdependingon thelimitationforthemelt-relateddensitycontrast(whichsimulatesvariabledegreeofmeltextraction).Particularly,sheet-likeplumestendnottodevelopdirectlyawayfromthesubductingslab,buttomoveupwardsalongtheslabifthedensitycon-trastislimitedto50-100kg/m3.Threepatternsofplumes(finger-likeplumesthatformsheet-likestructureparalleltothetrench;ridge-likestructuresperpendiculartothetrench; flattenedwave-like instabilitiespropagatingupwardsalongtheuppersurfaceoftheslabandformingzig-zagpatternsparalleltothetrench)showninpreviouswork[Zhu,etal.,inrevision]occurforthemodelswithdensitycontrast>200kg/m3and1019Pasviscosityofpartiallymoltenrocks.Finger-likeplumesdevelopinallofourmodelswithdensitycontrast>50kg/m3.Asapossibleapplicationofour3-Dnumericalstudytonaturalmagmaticphenomena,wealsocomparespace-timemeltproductivitypatterncomputedfromthemodelswiththedistributionandevolutionofvolcanicactivitiesintheintraoce-anicsetting.

REFERENCESGerya,T.V.2009:Introductiontonumericalgeodynamicmodelling,CambridgeUniversityPress(inpress),Chapter14and

15.Zhu,G.,Gerya,T.V.,Yuen,D.,Honda,S.,Yoshida,T.,Connolly,J.A.D.2009:3-Ddynamicsofhydrousthermal-chemicalplumes

inoceanicsubductionzones.Geochem.Geophys.Geosyst.(inrevision)

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y 3. Mineralogy-Petrology-GeochemistryBernard Grobéty, Eric Reusser

Swiss Society of Mineralogy and Petrology (SSMP)

3.1 AbidiR.,Slim-ShimiN.,HatiraN.,MejriZ.:Apportdesdonneesdesrayonx,decrystallographieetdesinclusionsflu-idesdansladeterminationdel’origineetlacompositionmineralogiquesdelaseriebarytine-celestitedugisementd’AinAllega,Tunisieseptentrionale

3.2 AlfanoF.,BonadonnaC.,VolentikA.,ConnorC.,WattS.,PyleD.,ConnorL.:TephraStratigraphyoftheMay,2008,ChaitenEruption,Chile

3.3 BaderT.,FranzL.,deCapitaniC.,RatschbacherL.,HackerB.,WeiseC.,WiesingerM.,PoppM.:MetamorphicevolutionoftheQinlingGroup,Qinlingbelt,eastcentralChina

3.4 BauerK.,VennemannT.,MulchA.:StableisotopesinprecipitationasproxiesfortheNeogenetopographicandclima-ticevolutionoftheAlps

3.5 BejaouiJ.,SellamiA.,SkaggsS.:Mineralogy,FluidinclusionsandsulphurisotopeinvestigationofthePb-Zn-Ba-(Sr)depositsatOuedJebs-KefLasfar,NorthTunisia

3.6 BoekhoutF.:GeologyandgeochronologyoftheIlobatholithofsoutherncoastalPeru

3.7 Bouvet de Maisonneuve C., Dungan M., Bachmann O., Burgisser A.: Melt inclusions from Volcán Llaima (38.7°S,AndeanSouthernVolcanicZone,Chile):Insightsintoshallowmagmastorageandcrystallization

3.8 BurgisserA.,BergantzG.:Unzippingofcrystalmushasarapidmechanismtoremobilizeandhomogenizemagmabodies

3.9 Cenki-Tok B., Oliot E., Thomsen T., Berger A., Spandler C., Rubatto D., Robyr M., Manzotti P., Regis D., Engi M.,GoncalvesP.:BehaviourofallaniteduringmylonitisationandimplicationsforU-Th-Pbdating:casestudyattheMtMucrone,Italy

3.10 ChiaradiaM.,MerinoD.,SpikingsR.:Rapidtransitiontolong-liveddeepcrustalmagmaticmaturationandtheforma-tionofgiantporphyry-relatedmineralization(Yanacocha,Peru)

3.11 CostantiniL.,PioliL.,LongchampC.,BonadonnaC.,ClaveroJ.:Complexevolutionofahighlyexplosivebasaltic-ande-siteeruptionofVillarricavolcano,Chile:theChaimilladeposit

3.12 DegruyterW.,DufekJ.,BachmannO.:Pumice,awindowintothevolcanicconduit

3.13 DessimozM.,MüntenerO.:Hornblendefractionationandperaluminoustonalite:anexampleoftheChelanComplex,WashingtonCascades,USA

3.14 Dijkstra,A.:PeridotitesonMacquarieIsland:evidenceforanciently-depleteddomainsintheEarth’smantlepointingtoglobalProterozoicmelting‘events’?

3.15 EfimenkoN.,SpangenbergJ.,SchneiderJ.,AdatteT.,MateraV.,FöllmiK.:SphaleritemineralisationinBajocianshal-low-watercarbonatesintheSwissJuraMountainsrelatedtoextensionalsynsedimentarytectonicsduringtheMiddle-LateJurassic.

3.16 HingerlF.,WagnerT.,KulikD.,KosakowskiG.,DriesnerT.,ThomsenK.,HeinrichC.:Modelingtheevolutionofgeo-thermalreservoirsindeepfracturedrocks:Couplingchemistrytoheatandfluidtransport

3.17 LeutholdJ.,MüntenerO.,BaumgartnerL.,PutlitzB.,OvtcharovaM.,SchalteggerU.,ChiaradiaM.:Themafic–graniticconnectionoftheTorresdelPainelaccolith,Patagonia

3.18 LouvelM.,Sanchez-ValleC.,MalfaitW.,PokrovskiG.,BorcaC.,GrolimundD.:Brominespeciationandpartitioninginhighpressureaqueousfluidsandsilicatemelts:implicationforthebehaviorofhalogensinsubductionzones

3.19 MalfaitW.,Sanchez-ValleC.,ArdiaP.,MédardE.:Compositionaldependentcompressibilityofdissolvedwaterinsili-categlassesrevealedbyBrillouinscatteringonhaplograniticandbasalticglasses

3.20 MantegazziD.,Sanchez-ValleC.,ReusserE.,DriesnerT.:PVTxpropertiesofhighpressureaqueousfluidsbyBrillouinscatteringspectroscopy

3.21 ManzottiP.,RegisD.,Cenki-TokB.,RobyrM.,ThomsenT.,RubattoD.,ZucaliM.,EngiM.:EvidenceofJurassicriftingintheDentBlanchenappe(nearCignana,Italy)

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3.22 Márquez-ZavalíaF.,HeinrichC.A.,MeierD.:Orefluidevolutioninavolcanic-hostedepithermaloredeposit:FarallónNegro,Argentina

3.23 MattssonH.,BosshardS.:Columnarjointingandtheformationof“chisel-marks”intheHrossadalurlavaflow,nort-hernIceland

3.24 MattssonH.,ReusserE.:BaggalútarfromHvalfjördur,SWIceland:Volcanicspherulitesornot?

3.25 MonnardH,ManzellaI.,PhillipsJ.,BonadonnaC.:ConvectiveInstabilitiesinVolcanicClouds

3.26 MonsefI.,RahgoshayM.,EmamiM.H.,ShafaiiM.:GeochemicalconstraintsonthedevelopmentofaMesozoicvolcano-tectonicarcandfore-arcbasinintheSanandaj-SirjanZone,southIran

3.27 MonsefR.,EmamiM.,RashidnejadOmranN.:TranstensionalbasinsysteminCentralIranianVolcanicBelt

3.28 MoulasE.,KostopoulosD.:Metamorphicevolutionofakyanite-eclogitefromThermes,RhodopeMassif,Greece

3.29 PistoneM.,CaricchiL.,BurliniL.,UlmerP.:Rheologicalpropertiesofcrystal-andbubble-bearingsilicicmagmas:pre-liminaryexperimentalresults

3.30 RegisD.,ManzottiP.,BostonK.,Cenki-TokB.,RobyrM.,RubattoD.,ThomsenT.,EngiM.:Complexities inthehighpressuremetamorphichistoryofthecentralSesiaZonenearCimadiBonze(NWItaly)

3.31 ReitsmaM.,SchalteggerU.,SpikingsR.,CarlottoV.:ThetemporalevolutionoftheMitugroup,south-eastPeru-firstU-Pbagedata.

3.32 RosaA.,Sanchez-ValleC.,WangJ.,SaikiaA.:Single-crystalelasticpropertiesofsuperhydrousphaseBdeterminedbyBrillouinscatteringspectroscopy

3.33 ScalisiR.,CostantiniL.,BonadonnaC.,DiMuroA.:Theinfluenceofvolatilesinbasalticexplosiveeruptions:theexa-mpleoftheChaimillaeruption(3.1Ka,VillarricaVolcano,Chile).

3.34 SemytkivskaN.,UlmerP.:AnexperimentalstudyinthesystemFe-Mg-Ti-Cr-Si-O±Al:ilmenitesolidsolutionasafunc-tionofpressureandtemperature

3.35 SergeevD.,DijkstraA.:PyroxeniteveinsintheJurassicPindosOphiolite(NWGreece):cm-scalemantleheterogeneitypreservedinMORB-sourceperidotites

3.36 ShafaiiH.,SternR.,RahgoshayM.:TheZagrosCollisionZone:PetrologicalandgeodynamicalconstraintsonInnerandOuterZagrosOphioliticBelt

3.37 SkopelitisAl.,BachmannO.:Thetransitionfromcold-wettohotter-drierrhyolitesinsubductionzones:thecaseoftheKos-Nisyros-Yalivolcaniccenter,Aegeanarc,Greece

3.38 Tercier-WaeberM.-L.,HezardT.,MassonM.:DynamicsofCd,PbandCucyclinginastreamundercontrastingphoto-benthicbiofilmactivityandhydrologicalconditions.

3.39 ThomsenT.,PettkeT.,AllazJ.,EngiM.:LAMBERN–softwareU-Pb,Th-PbandPb-PbagedatingbyLA-ICP-MSanalysis

3.40 TrittschackR.,GrobétyB.:Firstinsightsintothedehydrationoflizardite

3.41 TsunematsuK.,BonadonnaC.,FalconeJ.L.,ChopardB.:Analyticalandnumericaldescriptionoftephradeposition:theexampleoftwolargeexplosiveeruptionsofCotopaxiVolcano,Ecuador

3.42 Udry A., Müntener O.: Petrology of mafic-ultramafic complexes within the Archean Lewisian complex of NWScotland

3.43 VilsF.,DijkstraA.,PelletierL.,LudwigT.,KaltA.:Iridium-stripheaterglasspellets:EffectsoffusiontemperatureandtimeonLi,BeandBcontent

3.44 VoegelinA.,Samankassou,E.,NäglerT.:Molybdenumisotopesinmoderncorals:investigationintotheirpotentialasredoxproxyofbygoneoceans

3.45 WangJ.,Sanchez-ValleC.,StalderR.:Effectofminorelements (H+andAl3+)ontheelasticpropertiesoforthopyr-xenes

3.46 WiederkehrM.,BousquetR.,MasafumiS.,ZiemannM.,BergerA.,SchmidS.:DecipheringtheAlpineorogenicevolu-tionfromsubductiontocollisionalthermaloverprint:Ramanspectroscopyand40Ar/39ArageconstraintsfromtheValaisanOcean(CentralAlps)

3.47 ZurfluhF.,HofmannB.,GnosE.,EggenbergerU.,OpitzC.:ApproximateterrestrialagedatingofmeteoritesbyuseofhandheldXRF

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Apport des donnees des rayon x, de crystallographie et des inclusions flu-ides dans la determination de l’origine et la composition mineralogiques de la serie barytine -celestite du gisement d’Ain Allega. Tunisie septentrionale.

ABIDIRiadh*;SLIM-SHIMINajet**;HATIRANouri*;MEJRIZouhaier*

*: Faculté des sciences de Bizerte, département de géologie, Jarzouna-Bizerte.7021. Tunisie. **: Faculté des sciences mathématiques, physiques naturelles de Tunis. Campus Universitaire. 1060 Tunis. Tunisie. E.mail :abidi1riadh@yahoo.com ; najetshimi@yahoo.fr ; nouri_hatira@yahoo.fr ; mejrizouhair@yahoo.fr

Legisementd’AinAllegaetdetype«Cap-rocks»estsituésurlabordureorientaledudiapird’AinAllega.Laminéralisationestdiscordanteparapportàlarocheencaissante,elleseprésentesousformedecimentdesbrèches,sousformederemplis-sagedesfracturesetdescavitésdedissolutionetsousformederemplacementdelarocheencaissante(Dolomied’âgetria-sique).cegisementprésentunesimpleminéralisationcomposéparlagalène,lasaphalerite,lamarcasiteetlapyriteavecuneganguereprésentéparlabarytine,lacélestite,ladolomite,lacalciteetlequartz.L’étudepétrographiquedesminérauxdelasériebarytine–célestitemontrequ’ilspossèdentplusieursfacièsenparticuliermicrofibreux,saccharoïde,fibrolamel-laireetprismatique.

L’étuderadiocristallographiquedesminérauxdecettesériebarytinecélestite((BaX,Sr

1-X)SO

4)avecXЄ[0-1])prouvequ’ona

unevariétéd’espècesdeminérauxdontonabarytinepure(100%BaSO4)abondant,célestitepur(100%SrSO

4)abondant,ba-

rytinesrantianfère(85to96.5%BaSO4)minoritaireetcélestite-baryfère(95%SrSO

4)minoritaire.Cesminérauxvarieentre

euxselonledegrédesubstitutiondestrontium(Sr)parlebaryum(Ba)danslacelestite(SrSO4)etledegrédesubstitutionde

baryumparlestrontiumdanslabarytine(BaSO4).Cettesubstitutionesttrèsbienvisibledanslesdiffractogrammesaura-

yonsXdesminérauxdecettesériequiestmatérialiséparlavariationdelaposition,l’intensitéetlamorphologiedesraies200,011,113,312delabarytineetlabarytinestrantianitèreetlesrais410,401et122delacélestiteetlacélestitebaryféreetaussivariationdeladistanceréticulairedupicprincipaldelabarytinede3.44à3.42 pourlabarytinestrantianitère(fig.1).

L’étudedesinclusionsfluidescontenuesdanslacélestitepuramontréquelesinclusionsprimaireetsecondairemonopha-séesàliquidesontlesplusabondantes.Lesmesuresmicrothermométriquesprouvequelefluideminéralisateurestd’originehydrothermaleetquiestcaractériséparunetempératured’homogénéisationélevais(180°C)etunesalinitémoyenneàéle-vais(16%poidséqNaCl).Lerapportentrelatempératured'homogénéisationetlasalinité(fig.2)indiquequelasaumuredebasinavecunecertaineintroductiondefluidedemélangemagmatique-météoriqueétaitresponsabledelaminéralisationdemineraid’AinAllega.Lasalinitéélevéedecettesolutionaitrésultédelalixiviationetladissolutiondesunitésévapori-tiquesduTrias.

Figure.1.VariationdelapositiondupicprincipaldelabarytineenfonctiondudegrédesubstitutiondeBaryumparStrontiumdansla

barytine.

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Figure.2.Diagrammedecorrélationbinairetempérature–salinitédesinclusionfluidesdanslacélestitedugisementd’AinAllega

3.2

Tephra Stratigraphy of the May, 2008, Chaiten Eruption, Chile

F.Alfano1,C.Bonadonna1,A.C.M.Volentik2,C.B.Connor3,S.F.L.Watt4,D.M.Pyle4,L.J.Connor3

1. Department of Mineralogy, University of Geneva, rue des Maraichers 13, CH-1205 Geneva, Switzerland.2. Department of Geology and Geophysics, Volcanology, Geochemistry and Petrology University of Hawai'I, 1680 East-West Road, POST 614B, Honolulu, HI 968223. Department of Geology - SCA 528, University of South Florida, 4202 E. Fowler Ave., Tampa, FL, 33620, USA.4. Department of Earth Sciences, University of Oxford, Parks Road, OX1 3PR, UK

Abstract.OnMay22008MountChaiten,locatedinthesouthernChile,onthenorthernsectorofPatagonia,afteronly36hoursofprecursoryseismicactivity,interruptedalongperiodofquiescenceofmorethan9000years,producinghisfirsthistoricaleruptionandcausing thespontaneousevacuationofChaitenvillage, located fewkmfromthevent.The2008eruptionofChaitenisconsideredtobethelargestvolcaniceventsincetheeruptionofHudsonvolcano(Chile)in1991,andthefirstrhyoliticeventsincetheeruptionofNovarupta(Alaska)in1912.Theactivitywascharacterizedbyseveralexplosiveeventsassociatedwithplumesupto20kma.s.l.Theproductshavebeendispersedinawidearea(morethan200kmofdistance fromthecrater),withthefinestashreachingtheAtlanticcoastofArgentina.Satellite imagesclearlyshowthedevelopingofthecounterclockwiserotationofthedispersalaxisfromSSEtoNNErelatedtoashiftinwinddirection.Ourfieldobservationsinthemedialarea(5-20kmfromthevent)indicatethattheMay2008tephradepositconsistsofnumerouslayers,mostofwhichcanbecorrelatedwithindividualsmallexplosionsandsubsequentfalloutevents.Theselayersvaryfromextremelyfine-grainedtephratolayersoflapilliandlargeblocks,composedofbothjuvenileandlithicmaterial.Indistalarea(>200km),thefalloutdepositconsistsonlyofwhitetogreyfineandcoarseash,eventuallycontainingsomeac-cretionary lapilli.Although theMay2008eruptionwasofmoderate volume, tephra fallouthada substantial impact intermsofgenerationoflahars(inproximal-medialarea,upto20kmfarfromthevent),damagetovegetation(i.e.forestsandcrops)andremobilizationoffineashwitheffectstohumanandanimalshealth.Inthisworkweproposeareconstructionofthestratigraphyofthefirstevents,whichtookplacebetween2ndand8thMay2008andafirstphysicalcharacterizationoftheeruption.Themedialstratigraphyassociatedwiththefourmainexplosiveeventscouldberecognized:2nd-3rdMay,4th-5thMay,6th-7thMayand8thMay,withanestimatedcumulativevolumeof0.118±0.057km3(integrationofpower-lawfitting)Forthelastevent,representedbyalayercomposedmainlyoflithiclapilliandblocks(>2mm),anisoplethmapwascompiledandtheassociatedplumeheightwasdetermined.Theplumeisestimatedtobeabout19km,whencalculatedconsideringtheaverageofthegeometricmeanofthethreeaxesofthe5maximumclasts,andabout17km,whencalculatedconsider-ingthegeometricmeanofthethreeaxesofthe50thpercentileclast.Thesevaluesareclosetothesatelliteobservationsfortheeventofthe8thMay(i.e.about20kma.s.l.).

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Metamorphic evolution of the Qinling Group, Qinling belt, east central China

BaderThomas*,FranzLeander*,deCapitaniChristian*,RatschbacherLothar**,HackerBradleyR.***,WeiseCarsten**,WiesingerMaria**,PoppMichael**

*Mineralogisch-Petrographisches Institut, Universität Basel, CH-4056 Basel (thomas.bader@unibas.ch)**Institut für Geologie, Technische Universität Bergakademie Freiberg, D-09599 Freiberg***GeologicalSciences,UniversityofCalifornia,SantaBarbara,CA-93106

TheQinlingGroup,partoftheUpperProterozoic-TriassicQinlingbelt,mainlycomprisesfelsicgneisses,amphibolitesandmarbles. Itcanbesubdividedintotwoparts.ThenorthernmarginexperiencedaCambrianultrahigh-pressuremetamor-phismasevidentbytheoccurrenceofdiamondinclusionsinmetamorphiczircon(Yangetal.,2003).Thecentral-southernpartwasaffectedbymigmatisationwithinaDevonianmagmaticarccausedbyanorthwardtrendingsubductionzonefac-ingtheQinlingorogen(Ratschbacheretal.,2003,forareview).FewdataonthemetamorphicevolutionofthesouthernpartoftheQinlingGroupwerepublishedbyYouetal.(1993)whilesuchdataarelackingforthenorthernmargin.Inthecurrentstudy,wepresentnewpetrologicdataforbothpartsderivedbymeansofequilibriumphasecalculationsandconventionalgeothermobarometrycombinedwith40Ar/39ArandTh/Pbgeochronology.

EclogitesfromtheNorthernmarginoftheQinlingGrouparefinetomedium-grained,weaklyfoliatedrocksthatoccuraslenseswithdiametersupto2mmantledbyphengitegneisses.Texturally,oursamplesgiveindicationsfortheUHPeventbynumerousradialcracksaroundquartzinclusionsingarnetpointingtoformercoesite.Theassemblageofthepressurepeakcomprisesgarnet(core)–omphacite–coesite–phengite–rutile.However,modellingusingtheDOMINOprogramandtheapplicationofconventionalgeothermobarometersyieldedquartz-eclogitefaciesconditionsof~600°Cat1.8-2.2GParepre-sentinganearlyexhumationstage.Theexhumationhistoryof theeclogitic rocks is furtherconstrainedby the lateam-phibolitefaciesmineralassemblagegarnet(rim)–amphibole–plagioclase–quartz–ilmenitepointingto~650°Cat1.0-1.4GPa.Thiswasverifiedbyconventionalthermobarometryongarnetamphibolite75221Candgarnetgneiss75214Dfromthesameunitpointingto630-660°Cat1.0GPa(fig.1,left).

ThecentralandsouthernpartsoftheQinlingGrouprevealhigh-grademetamorphicPTconditionsasevidentbymigmatisa-tionoffelsicgneisses.Peakmetamorphicassemblagesinmetapeliticgneissescomprisegarnet–plagioclase–Kfeldspar–quartz–sillimanite–ilmeniteandgarnet–hornblende–plagioclase–quartz–ilmeniteinmetabasites.PTestimatesusingtheDOMINOprogramandconventionalgeothermobarometrypointto600-730°Cat0.3-0.7GPa(fig.1,right).ThelowerPTconditionsareinterpretedtoindicatearetrogradedevelopmentofthemetamorphism.Noindicationofeclogitefaciesmeta-morphismwasfoundinthegneissesandamphibolites.However,thefindingofasmallbodyofstronglyoverprintedspinelperidotite inthesouthernpartofthisprofile,whichhadre-equilibratedto630-670°C (i.e. identicaltemperaturestothesurroundinggneissesandamphibolites),pointstoaprobableearlyHPevent.

40Ar/39ArdatingofphengitesfromthenorthernmarginoftheQinlingGroupyields470±1Ma.Significantlyyoungerageswereobtainedbydatingmetamorphicmonazite(Th/Pb,340-395Ma),hornblende(40Ar/39Ar,373-395Ma)andbiotite(40Ar/39Ar,330-390Ma)fromthecentralandsouthernQinlingGroup.

ThesefindingsprovethattheexhumationoftheUHPmetamorphicstookplaceinEarly-toMid-Ordovician.Therocksofthecentral-southernQinlingGroupunderwentaDevonianultrametamorphisminthemiddlecrustwithinamagmaticarcset-tingwithhighheatflow.Furtherinvestigationswillshow,howbothsubunitshadbeenjuxtaposed.

REFERENCESRatschbacher, L.,Hacker,B.R.,Calvert,A.,Webb, L.E.,Grimmer, J.C.,McWilliams,M., Ireland,T.,Dong, S.&Hu, J. 2003:

Tectonics of the Qinling Belt (Central China): Tectonostratigraphy, geochronology, and deformation history.Tectonophysics366,1-53.

Yang,J.,Xu,Z.,Dobrzhinetskaya,L.F.,GreenII,H.W.,Pei,X.,Shi,R.,Wu,C.,Wooden,J.L.,Zhang,J.,Wan,Y.,Li,H.,2003:Discovery ofmetamorphicdiamonds in centralChina: an indicationof a > 4000-km-long zoneofdeep subductionresultingfrommultiplecontinentalcollisions.TerraNova,15,370-379.

You,Z.,Han,Y.,Suo,S.,Chen,N.&Zhong,Z.,1993:MetamorphichistoryandtectonicevolutionoftheQinlingComplex,easternQinlingMountains,China.JournalofmetamorphicGeology,11,549-560.

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Figure1:left:MetamorphicdevelopmentofthenorthernmarginoftheQinlingGroup.Right:PTestimatesofthecentral-southern

QinlingGroup.

3.4

Stable isotopes in precipitation as proxies for the Neogene topographic and climatic evolution of the Alps

BauerKerstin*,**,VennemannTorsten*,MulchAndreas**

*Institut de Minéralogie et Géochimie, Anthropole, Université de Lausanne, CH-1015 Lausanne, Switzerland (Kerstin.Bauer@unil.ch) ** Institut für Geologie, Leibniz Universität Hannover, Callinstr. 30, 30167 Hannover, Germany

Thepaleoelevationofamountainbeltisanimportantparametertounderstanditsevolutionandsetsconstraintsonupliftanderosionratesandalsoonthepaleoclimate.Aquantitativetooltodeterminethisisthealtitudeeffectonthestableiso-topecompositionofprecipitation,sincetheδ18OandδDvaluesinprecipitationdecreasewithelevation.

Precipitationofthepastcanbepreservedinsurface-formedhydroussilicatesandalso,afterinfiltrationviafaultsandshearzones,inmetamorphicmineralswhichinteractedwithmeteoricwaterand/ortrappedthiswaterasfluidinclusions.

ThisstudyaimstoreconstructthechangesinisotopiccompositionofprecipitationandthuspalaeoelevationoftheEuropeanAlpsduringtheMiocene.Therefore,isotopiccompositionsofmineralsderivedfromsurfacealterationand/orfaultgaugesofdifferentlocalitiesintheAlpswillbestudied.

Toobtainacorrectionfortheclimaticconditionswhichcanalsochangethe18O/16OandD/Hratios,lowelevationmaterialfromtheAlpineforelandcoveringthesametimeperiodwillalsobeanalyzed.ClaymineralsfromtheMolassebasinappeartobepromisingmaterialandpaleoclimateinformationderivedforsealevelconditionsfromseveraloftheselayersalreadyexistfromstudiesofmarinefossils.

Additionally,sampleswillbeanalyzedfrompresentsoilhorizonstofurtherexaminethelocaldependencesofisotopicvari-ationswithelevationandtheuptakeoftheisotopiccompositionfromrainwaterintothemineralsformed.

REFERENCESJanz,H.&Vennemann,T.W.,2005:Isotopiccomposition(O,C,SrandNd)andtraceelementratios(Sr/Ca,Mg/Ca)ofMiocene

marine and brackish ostracods fromNorth Alpine foreland deposits (Germany and Austria) as indicators forpaleoclimate.Palaeogeography,Palaeoclimatology,Palaeoecology225(2005),216-247.

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y Kocsis,L.,Vennemann,T.W.,Hegner,E.,Fontignie,D.,&Tütken,T.,2009:ConstraintsonMioceneoceanographyandclimateintheWesternandCentralParatethys:O-,Sr-,andNd-isotopecompositionsofmarinefishandmammalremains.

Palaeogeography,Palaeoclimatology,Palaeoecology271(2009),117-129.Mulch,A.,Teyssier,C.,Cosca,M.A.,Vanderhaeghe,O.,&Vennemann,T.W.,2004:Reconstructingpaleoelevationineroded

orogens.Geology32,6(2004),525-528.Mulch,A.&ChamberlainC.P.,2007:StableIsotopePaleoaltimetryinOrogenicBelts–TheSilicateRecordinSurfaceand

CrustalGeologicalArchives.ReviewsinMineralogy&Geochemistry66(2007),89-118.

3.5

Mineralogy, Fluid inclusions and sulphur isotope investigation of the Pb-Zn-Ba-(Sr) deposits at Oued Jebs-Kef Lasfar, North Tunisia

JaloulBEJAOUI*,AhmedSELLAMI**andS.A.SKAGGS***

* Centre National des Sciences et Technologies Nucléaires, Tunisie, bjaoui_geo@yahoo.fr ** Office National des Mines, Tunisie *** Department of Geology, University of Georgia, 210 Field St, Athens, GA 30602, USA

TheOuedJebs-KefLasfarPb-Ba-Zn-(Sr)depositislocatedinnorthernTunisia,60KmfromTunis(Fig.1).Sulfidesmineraliza-tion ismainlyassociatedwithCenomanian-Turonian inter-layered limestoneandmarlsof theCretaceous,whichreplacecarbonate,cementedbrecciasandcavities(Fig.2).ThegeologyoftheareaisdominatedbymassivelimestoneandmarlylimestoneunitsofCretaceousage,whichareexten-sivelyfolded.Theoredepositconsistsofasystemofmineralizedveinsandbreccias,extendingoveranareaof15km2.Theore-hostinglimestonelayersarecharacterizedbyastrongkaoliniteenrichment,inamountsdirectlyrelatedtotheproporti-onoftheoreminerals.Themineralization lies mainly within the organic-rich black shale succession of the Bahloul Formation (Cenomanian-Turonian)andtoalesserextentalongthetransitionzonebetweenTriassicandCretaceous),wherezebra-texturedcelestitelayersalsooccur (Fig.3).Thecelestite-calcite rhythmites,whosestructure iscausedbygrainsizevariation,occurmainlyaroundtherisingsaltdiapirs.Kaoliniteisassociatedwithhydrothermalmineralizationandoccursintheparagenesisofthesulfidesinbreccias(Fig.3).ThemineralogicalcharacteristicsofkaoliniteweredeterminedbyX-raypowderdiffractionandtheyare7,15A°(d001)and3,57A°(d002)andisattenuatedafterheating.Treatmentwithethyl-glycolhadnoeffect.Fluidinclusionswereinvestigatedinhydrothermalbariteassociatedwithsphaleriteandgalena.Alltheobservedfluidin-clusionsare two-phase liquidandvapor inclusions, but theaqueous fluid inclusions inbaritewhich couldbeanalysed,rangeinsizefrom20to100µm.Primaryinclusionsexhibithomogenizationtemperature(Th)meanvaluesrangingfrom110°Cto140°C,withsalinitiesof14to18wt.%NaClequiv.ThemicrothermometricdataareinagreementwiththosemeasuredintheJebelAjeredPb-Zn-Baoredeposit(Bejaouietal.,2008).MicrothermometricdataoffluidinclusionsrevealtheinvolvementofbasinalbrinesinmineralizationofOuedJebs.δ34SvaluesinsphaleriteandgalenaatOuedJebs-KefLasfarrangefrom0.7‰to5.3‰.Thesepositivevaluessuggestanoriginfromevaporitesulfates,followedbythermochemicalreduction(Claypooletal.,1980).The present fluid inclusions study demonstrates the involvement of basinal brines in mineralization of Oued Jebs-KefLasfar.

Key words:basinalbrines-OuedJebs-KefLasfar-Fluidinclusions-Pb-Zn-Ba-(Sr).

AcknowledgmentsWearegratefultoPr.MariaBONIforhelpfulcommentsandsuggestions.REFERENCESBejaouiJ.,BouhlelS.,CardellachE.,andPiquéÀ.(2008)-MineralogyandfluidinclusionstudyofcarbonatehostedPb-Zn-Ba-

(Cu)depositsinJebelAjered,CentralTunisia.6SwissGeoscienceMeeting(SGM)2008,173-175.ClaypoolG.E,HolseerW.H.,KaplanI.R.,SakaiH.,andZakI.(1980)-Theagecurveofsulphurandoxygenisotopesinmarine

sulphateandtheirmutualinterpretation.Chem.Geol.,28,163-187.

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Fig 1. Location of the Oued Jebs ore deposit within the diapirs zone in Tunisian structural map.

Fig 2. Cross section of Oued Jebs Pb-Zn-Ba-(Sr) ore deposits. : 1 Eocene: bioclastic limestone and marls, 2 Cenomanian-Turonian: marly li-

mestone, 3 Albian: marl and limestone, 4 Aptian: carbonate series within silty clay layers. 5 transition zone: marls and dolomite-rich “ze-

bra” celestite, 6 Trias: evaporites, 7: Pb-Zn-Ba-(Sr) orebodies, 8 faults.

Fig 3. A Cenomanian limestone affected by fault and fractures, B Mosaic breccias cemented by sulfides mineralization, C Marls rich in ka-

olinite mineralized with massive galena, D Mosaic breccias cemented with kaolinite and disseminated galena.

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Geology and geochronology of the Ilo batholith of southern coastal Peru

BoekhoutFlora*,ThierrySempere**,RichardSpikings*,UrsSchaltegger*

*Earth and Environmental Sciences, Rue de Maraîchers 13, CH-1205 Genève**IRD et LMTG, 14 Avenue Edouard Belin, 31400 Toulouse, France

InSoutherncoastalPerutheso-calledIlobatholithisemplacedinthe‘Chocolate‘formation,ofEarlytoMiddleJurassicage,thatcomprisesmorethan1000mofbasalticandandesiticflows,agglomeratesandbreccias.Previousworkershavecorrela-tedthedioritictogranodioriticrocksofthisintrusionwiththe‘CoastalBatholith‘ofCretaceoustoPaleogeneage.However,K-ArandAr-ArgeochronologyofplutonicrocksnearthecityofIlopointtoEarlyJurassicages(Clarketal.1999,Sánchez1983a).Thispartoftheplutonicassemblagewasthusemplacedpriortotheinitiationof‘Coastalbatholith‘emplacement.Maficandfelsicgranitoidmagmasareintimatelyassociated,asreflectedbytheemplacementofmixeddiorite-granodioriteunits.Also,maficandfelsicmagmaminglingnorthofIlohavebeenobserved,e.g.globularenclavesofdioriteingranodio-rite,elongated inclusions,bothbasalticandcomposite (basaltic/dacitic) synplutonicdikes: thusnosimplemafic to felsicintrusivesequenceprevailedduringbatholithconstruction.OuraimistodescribeandinterpretthehistoryoftheIlobatholithandtodiscusshowthemagmatichistoryofthisbatholithfitsintotheframeworkofmagmagenesisandmodesofemplacementalongtheactiveAndeanmargin.ThisfirstoccurenceoflargevolumesofplutonicrocksmaywellrepresentthefirststagesofAndeansubduction(Oliverosetal.2006).Acombinationoffieldobservations,zirconU-Pb(LA-ICP-MSandCA-ID-TIMS)data,andelementgeochemistryofthebatho-lithwillbeused todistinguishbetweendifferentmagmaticpulsesand theirduration.AdditionalSr,Nd,Pb,Hf isotopestudieswillbecarriedout,specifyingthemagmaticsourceofthedifferentpulsesofplutonicactivity.

Eastwardtiltingof20-30°hasexposedacompletecross-sectionofthebatholithinmapviewwithannorth-northeastwardpaleo-updirection,revealingthattheIlobatholithhasatabularshape:WearethereforeabletostudythecontactwiththeChocolateformationaboveandbelowthebatholith,includingasamplingcampaignalongseveralcrosssectionsthroughthebatholithfordatingandgeochemicalanalyses.Inadditiontosamplesfromthebatholithitself,clasticsedimentaryrocksaboveandbelowthebatholithhavebeensampledinordertodeterminetheirmaximumdepositionalagebydatingdetritalzirconsusingLA-ICP-MS.Inthiscasethesameorverysimilardetritalzirconpopulationsshouldbefoundinbothlocations(belowandabovethetabularplutonicbody),astheywereoriginallyjuxtaposed.

Preliminarydataof3samplesdatedbyU-PbTIMSshowapulseofmagmatismat~164MawithanepsilonHfrangingfrom+4to+6.9indicatingadepletedmantlesourcetypicalofcontinentalmarginsettings.Thegeochemicaldatasuggestacalc-alkalinemagmasource.McBrideetal(1983)postulatedtwointrusivepulsesonthebasisofsixconventionalK-ArdatesonfourgranitoidsamplesintheIloareaofLateJurassic(ca.151–159Ma)andmid-Cretaceous(96–111Ma).Sánchez(1983a)obtainedsimilarAlbianK-ArdatesforseveralgranodioriticsamplesnortheastofIlobutalsofoundEarlytoMiddleJurassicdates(196-182Ma)fortwodioriticrocksfromthecoastalzone.Ourpreliminarydatamightindicateanothermagmaticpulse,orshowalongerdurationofoneofthepreviouslydecribedpulses.

REFERENCESClarkAlanH,FarrarEdward,KontakDanielJ.,LangridgeRobertJ.1999:GeologicalanGeochronologicalConstraintsonthe

MetallogenicEvolutionoftheAndesofSoutheasternPeru,EconomicGeology,85,1520-1583.OliverosVeronica,FéraudGilbert,AguirreLuis,FronariMichel,MorataDiego2006:TheEarlyAndeanMagmaticProvince

(EAMP):40Ar/39ArdatingonMesozoicvolcanicandplutonicrocksfromtheCoastalCordillera,northernChile,JournalofVoclanologyandGeothermalResearch,157,311-330.

McBride,S.L.,Robertson,R.C.R.,Clark,A.H.,andFarrar,E.1983:Magmatismandmetallogeneticepisodesinthenortherntinbelt‘CordilleraReal’Bolivia,Geol.Rundschau,72,685–713.

Sánchez,A.W.,1983:EdadesK-ArenrocasintrusivasdelareadeIlo,Dpto.deMoquegua,Geol.Soc.PeruBol,71,183–192.

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Melt inclusions from Volcan Llaima (38.7°S, Andean Southern Volcanic Zone, Chile): Insights into shallow magma storage and crystallization

BouvetdeMaisonneuveCaroline*,DunganMichael*,BachmannOlivier**&BurgisserAlain***

* Départment de Minéralogie, Rue des Maraîchers 13, CH-1205 Genève (caroline.bouvet@unige.ch, Michael.Dungan@unige.ch)**University of Washington, Earth and Space Sciences, Seattle, WA 98195-1310 (bachmano@u.washington.edu)*** Institut des Sciences de la Terre d'Orléans - CNRS, Fr-45071 Orléans (burgisse@cnrs-orleans.fr)

Olivine-hostedmelt inclusions in scoria from four large historic eruptions of Llaima are used to elucidate processes ofmagmadifferentiation, recharge,mixing,anderuption triggering.ThesedepositswereproducedasviolentStrombolianeruptionsofcrystal-richmaficmagma(<6wt%MgO;25-45%plag+oliv±cpx)associatedwithvoluminouslavaflows.Majorelementmeltinclusioncompositionsarehighlydiverseinsinglesamples(50-58wt%SiO

2;6-3wt%MgO).Theseoverlapwith

thewhole-rockdatatrenddefinedbytheentirevolcanoupto53-55%SiO2,butmoreevolvedcompositionsformadivergent,

lineartrendupto>2wt%TiO2withAl

2O

3aslowas12.5wt%at57-58wt%SiO

2,comparedto1.2-1.4wt%TiO

2and16-17wt%

Al2O

3at58wt%SiO

2inmostLlaimaandesiticmagmas.Theevolvedextensionofthemeltinclusiontrendisinferredtobe

theproductofshallowevolutionofinterstitialmeltduringtheformationofcrystalmushasaconsequenceofdegassinganddecompressioncrystallizationfollowingmagmastagnation.ThesuppressionofFeTi-oxidestabilityandthedominanceofplagioclasecrystallizationareconsistentwithlow-Pdryconditions.TheseobservationsareinaccordwithrelativelylowH

2O

(dominantly1-3.5wt%)andCO2(dominantly0-300ppm)contentsinmeltinclusions(SIMS-ASU),whichyieldsaturationpres-

suresof~300-500bars(<2km).H2OandCO

2contentsdonotcorrelatewithmajorelementmeltcomposition,andmeltinclu-

sionfluid-saturationpressuresdonotcorrelatesystematicallywithfractionationindicessuchasK2OorMg#.Corollariesto

theseobservationsarethatdegassedmatrixglassesattachedtomanyoftheseolivinesarecommonlylessevolvedthancor-respondingmelt inclusions (generally inequilibriumwithhostolivines),olivinecorecompositions insinglesamplesarediverse (Fo

69-83),andmanyof theseolivinesarereverselyzonedtorimsofFo

77-79.Theabsenceofcorrelateddegassingand

magmaevolutiontrends inhistoricLlaimamagmassuggests that theyarestoredasmultiplebodiescreatedbyahigherfrequencyofmagmareplenishmentincomparisontothefrequencyoflargeeruptions.Thistemporal-spatialdisconnectionleadstoisolatedevolutionanddegassingofdiscretemagmabatches,followedbyassemblyjustpriortoeruption.Injectionofrelativelyhotandmaficgas-richmagmaisprobablythetriggeringmechanism,inaccordwithandhigherOlivine-Melttemperaturesrecordedbyrelativelyprimitivematrixglasses.

3.8

Unzipping of crystal mush as a rapid mechanism to remobilize and homogenize magma bodies

BurgisserAlain*,BergantzGeorge**

*ISTO, CNRS - University of Orléans, 1a rue de la Férollerie, 45071 Orléans cedex 2, France (burgisse@cnrs-orleans.fr)**Dept. of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 USA

ThelargestproductsofmagmaticactivityonEarth,thegreatbodiesofgraniteandtheircorrespondinglargeeruptions,haveadualnature:homogeneityatthelargescaleandspatialandtemporalheterogeneityatthesmallscale.Thisdualitycallsfor amechanism that 1) removes selectively the large-scaleheterogeneities associatedwith the incremental assembly ofthesemagmaticsystemsand2)occursrapidlydespitecrystal-rich,viscousconditionsseeminglyresistanttomixing.

Wepresenta simpledynamic template canunifyawide rangeof seemingly contradictoryobservations fromboth largeplutonicbodiesandvolcanicsystemsbyamechanismofrapidremobilization(“unzipping”)ofhighlyviscouscrystal-richmushes.Wedemonstrate that this remobilizationcan lead to rapidoverturnandproduce theobserved juxtapositionofmagmaticmaterialswithverydisparateagesandcomplexchemicalzoning.Whatisnovelaboutourmodelistherecogniti-onthattheprocesshastwostages.Initiallyastiffmushymagmaisreheatedfrombelowproducingareductionincrystalli-nitythatleadstothegrowthofasubjacentbuoyantmobilelayer.Asecondstageoccurswhenthethickeningmobilelayer

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TheagreementbetweencalculatedandobservedunzippingratesforhistoricaleruptionsatPinatuboandatMontserratde-monstratesboththegeneralapplicabilityofthemodelandtheabilityofunzippingtorapidlyproducelargeamountsofmobilemagmaavailableforeruption.Thismechanismfurthersourunderstandingofthebifurcationbetweencrustbuil-dingbyformationofperiodicallyhomogenizedplutonsandignimbriteformationbylargeeruptions.

3.9

Behaviour of allanite during mylonitisation and implications for U-Th-Pb dating: case study at the Mt Mucrone, Italy

Cenki-TokBénédicte*,OliotEmilien**,ThomsenTonnyB.*,BergerAlfons***,SpandlerCarl****,RubattoDaniela*****,RobyrMartin*,ManzottiPaola*,RegisDaniele*,EngiMartin*andGoncalvesPhilippe**

*Uni. Bern, IfG, Baltzerstr. 1+3, 3012 CH-Bern (cenkitok@geo.unibe.ch)**Uni Franche-Comté, UMR6249, 16 rte de Gray, F-25030 Besançon***Uni Copenhagen, Institute for Geography and Geology, Øster Voldgade 10, DK-1350 Copenhagen****James Cook University, 101 Angus Smith Dr, QLD 4811 Townsville, Australia*****Australian National University, 0200 Canberra, Australia

Allaniteoccursinmeta-granodioriteshowingdifferentamountsofstrain,fromundeformed(a)tomylonitic(f).ThisbodyintrudedthepolycyclicSesiabasementatPermiantimesandunderwentHPmetamorphismandductiledeformationduringtheAlpineconvergence.WestudytheeffectsofdeformationonallaniteU-Th-Pbapparentages.In the mylonitic rock allanite forms mm-size angular grains in a strongly recrystallised matrix and shows exclusivelyPermianages,eventhoughthegrainsareintimatelylinkedtoAlpinedeformationandmetamorphism.Thesegrainsoccurinmm-sizedlensesaroundwhichthemyloniticfoliationflows.Inadditiontoallanite,theselensesarecomposedofrandom-ly oriented phengite and Ca-rich garnet (up to 30wt%). During mylonitisation these allanite grains were mechanicallyshieldedbyarobustmineral(epidote)thatsubsequentlybrokedowntogarnetandphengite.Theundeformedrockgivesinsightintoallaniteformingreaction.RelicsofPermianmagmaticmonazitearefoundexclusi-velyintheundeformedsampleswherethemagmatictexturesandmineralsarelargelypreserved.Coronasofallanite,thoriteandapatitesurroundmonaziterelicsindicatingthereaction:monazite+plagioclase+fluid--->allanite+apatite+thorite.ThesetexturesarelocatedatthecontactwheremagmaticbiotiteandplagioclasebreakdowntoformtheHPassemblagephengiteandgarnet.Alpineallaniteisfoundintheundeformedrock.Itismuchsmaller(ca.200µm),presentfragmentedtextureswithsatelliteneocrystals,isrichinSr(upto2wt%)andhasapositiveEuanomaly.Inmediumstrainrockssmall(<20µm)Sr-richrimsaroundPermianallanitecanbefound.ThisindicatesthatAlpineallanitecrystalisationisclearlyassociatedtoplagioclasebreakdown(plagioclase+H2O--->jadeite+zoisite+quartz)andmusthavebeentriggeredbylocalfluidpresentconditions.The interpretation of these complex textures, microstructures and ages needs superposition of at least two events. AtPermiantimes,mm-sizedallaniterimedbyepidotemostprobably formed in latemagmatic fracturesassociatedto fluidcirculation.AtAlpinetimes,thesefracturesplaytheroleofprecursorheterogeneitieswhereductiledeformationis loca-lized.AllaniteinthemyloniteismechanicallyandchemicallyshieldedduringtheAlpineevent.Allaniteisarobustchronometer.Howeverincaseofsuperpositionofdeformationevents,itsPbisotopecompositionmaynotrecordalltheeventsseenbytherock.ReworkingofoldstructuresduringtheAlpineorogenyhastobetakenintoac-countwheninterpretingagesonallaniteindeformedrocks.Adeeperlookintotexturesandstructures–thatcanbemis-leadingatafirstglance–isnecessarytounderstandthesignificanceofU-Th-Pbinsituagesinpolycyclicrocks.

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Rapid transition to long-lived deep crustal magmatic maturation and the formation of giant porphyry-related mineralization (Yanacocha, Peru)

ChiaradiaMassimo*,MerinoDaniel*,SpikingsRichard*

*Département de Minéralogie, Rue des Maraîchers 13, 1205-Genève (Massimo.Chiaradia@unige.ch)

Anexpandingamountofliteratureoverthepreviousdecadereportstheoccurrenceofmagmaticrockswithgeochemicalfeaturesofadakites(oradakite-like;i.e.,highSr/Y,lowYb)inassociationwithmajorporphyryCu-Auandporphyry-relatedepithermaldeposits,andatwofoldscientificdebatehasdevelopedaboutthisquestion:ononehandthegenesisofadakite-likerockiscontroversial;ontheotherthemeaningitselfoftheassociationofporphyry-typedepositswithadakite-likerocksisdebated.

Rockswithadakite-likefeaturesareconsideredtobetheresult,amongothers,ofslabmeltingandslabmelt-mantlewedgeinteractions(e.g.,DefantandDrummond,1990),ofmaficlowercrustalmelting(e.g.,AthertonandPetford,1993),orofhigh-pressurefractionalcrystallizationaccompaniedornotbytheassimilationandmeltingoflowercrust(e.g.,Chiaradiaetal.,2009).Discriminationbetweentheseprocessesisnotstraightforward,whichhasledtocontroversyontheoriginofrockswithadakite-likesignaturesinmanyPhanerozoicarcsystems.Thedebatedoriginoftheserockshaspropagatedintocon-trastingmodelsexplainingthemechanismsoftheassociationbetweenadakite-likerocksandporphyry-typedepositsinva-riousPhanerozoicarcenvironmentsandpost-collisionalzones(e.g.,reviewofRichardsandKerrich,2007).Anyhypothesisaccountingfortherelationshipsbetweenadakite-likerocksandporphyry-typedepositsshouldbebasedonathoroughpe-trogeneticstudythatistightlycoupledwiththetemporalevolutionofmagmaticrocksandtheirrelationshipswithmine-ralization.

Herewereportgeochronologic,geochemicalandisotopicdatafromadakite-likeporphyriticrocksassociatedwiththegianthigh-sulfidationsystemofYanacocha,northernPeru,whichistheworld’slargestgolddepositofthistype.Mineralizationisassociatedwithporphyriticintrusionsdistributedalonga~8kmlongNE-trendingmagmaticstructuralcorridor.Eightofthese intrusions investigated in this study range in age from12.4 to 8.4Ma and show systematic chemical and isotopicchangesthroughtime.Inparticular,rocksbecomesystematicallymorefelsic(andesitetorhyodacite),adakite-likeandisoto-picallycrust-contaminatedthroughtime,witharapidtransitionfromnonadakitictostronglyadakite-likesignaturesoccur-ringatabout12Maandwithinatimeintervalof<0.5Ma.

Basedonpetrography,mineralandrockchemistryandisotopiccompositionstheYanacochaintrusivemagmasareinterpre-tedtobetheresultofrechargeassimilationfractionalcrystallization(RAFC)processesoccurringatdifferentcrustallevels,involvingamphibole-clinopyroxene-garnetfractionationatdeeperlevels,leadingtomoreorlessstrongadakite-likesigna-tures,andplagioclase-amphibole fractionationat shallower levels.Systematicgeochemicaland isotopicchanges throughtime,coupledwithplagioclasezoningandamphibolegeobarometrysuggestthattheevolutionofthemagmaticsystemoc-curred through interactionofandesiticmeltswithan increasing lengthof thecrustalcolumnandshiftedprogressivelythroughtimetowardsshallowercrustallevelsasindicatedbyadecreaseinadakiticindicesbetween11-8.4Ma(althoughtherocks remained strongly adakite-like throughout) and by overall decreasingminimal pressures of amphibole crystalliza-tion.

ThisevolutionwaspossiblytheresultofasteadilyincreasingcompressionassociatedwiththeQuechuaIIorogenicphase(12-10Ma) that, byprogressively slowingdownmagmaascent, forcedmagmas to evolve at a series of intermediate levelchambersbetweentheloweranduppercrust.IncreasedcompressionduringtheQuechuaIIorogenicphasemighthavebeenrelatedtotheonsetofsubductionofthebuoyantIncaoceanicplateau,estimatedtooccurat~12Ma(Gutscheretal.,1999),i.e.,thesametimeoftheonsetoftherapidtransitionfrom“normal”toadakite-likesignatures.

ThegiantYanacochaoresystemdevelopedincoincidencewiththeensuing~3.6My-longintrusionofadakite-likemagmasformedbytheaboveprocessesintoasmalluppercrustalvolume(correspondingtoasurfaceareaof~5km*5km).Thissug-geststhatlarge-scalegeodynamicprocessesleadingtoprolongedmagmaticevolutionatdeepcrustallevelsmightbeafirst-ordercontrolontheformationofgiantporphyry-typesystems,asisalsoindicatedbysimilarmagmaticevolutionsinotherporphyry-systemsworldwide.Howthisoccursindetail(e.g.,generationofvolatile-andmetal-richoxidizedmagmasthroughhigh-pressurefractionation,recyclingofsulfide-richcumulatesinthelowercrust,focussedandlong-livedmagmaticinputintoasmalluppercrustalvolume)requiresadditionalinvestigation.

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y REFERENCESAtherton,M.P.,&Petford,N.1993:Generationofsodium-richmagmasfromnewlyunderplatedbasalticcrust.Nature,362,

144-146.Chiaradia,M.,Müntener,O., Beate, B.,& Fontignie,D. 2009:Adakite-like volcanismof Ecuador: lower crustmagmatic

evolutionandrecycling.ContributionstoMineralogyandPetrology,inpress,DOI10.1007/s00410-009-0397-2.Defant,M.J.,&Drummond,M.S.1990:Derivationofsomemodernarcmagmasbymeltingofyoungsubductedlithosphere.

Nature,347,662-665.Gutscher,M.-A.,Olivet, J.-L.,Aslanian,D.,Maury,R.,&Eissen, J.-P. 1999:The "lost IncaPlateau":Causeof flat subduction

beneathPeru?.EarthandPlanetaryScienceLetters,171,335-341.Richards,J.P.,&Kerrich,R.2007:Adakite-likerocks:theirdiverseoriginsandquestionableroleinmetallogenesis.Economic

Geology,102,537-576.

3.11

Complex evolution of a highly explosive basaltic-andesite eruption of Villarrica volcano, Chile: the Chaimilla deposit

CostantiniLicia*,PioliLaura*,LongchampCeline**,BonadonnaCostanza*&ClaveroJorge***

*Départment de Minéralogie, Rue de Maraîchers 13, CH-1205 Genève (licia.costantini@unige.ch)**Institute of Geomatics and Risk Analysis, Amphipôle - CH-1015 Lausanne***Servicio Nacional de Geologia y Mineria (Sernageomin), Chile

Villarricaisa2847-m-highbasaltic-andesiticstratovolcanolocatedinthesouthernChileanAndes.ItisoneofthemostactivevolcanoesinSouthAmericaandithasbeenactivefor600kaproducingabout60eruptionsinthelast450years.Althoughitshistoricaleruptiveactivityhasbeenmainlyeffusiveandweaklyexplosive,withmorethan30knowneruptionsin the last century,Villarricavolcanoalsohad largepostglacialexplosivebehaviour,whichproducedpyroclasticdensitycurrentsandtephrafalloutfromboththecentralventandflankparasiticpyroclasticcones(ClaveroandMoreno2004).Thetwoknownlargest-volumeeruptionsare theLicánandPucón ignimbrites (13.8and3.6karespectively),whichproducedwidespreadpyroclasticdensitycurrentsandarelikelyassociatedtocalderaformation.Thebest-preservedandwidelydisper-sedpyroclasticfalloutistheChaimilladeposit,whichwaseruptedafterthecaldera-formingPucónignimbrite(~3.1ka).Afterthelastlargeeruption(1984-85),theVillarricaactivityhasbeencharacterizedbycontinuousdegassingandsporadicbubblebursts(Witteretal.,2004;Guriolietal.,2008).

We present the stratigraphy of Chaimilla deposit combinedwith the grain size, componentry, density, vesicularity andgroundmasstexturesofjuvenileproductsfromselectedfalloutbeds.Thesedataareusedtoestimatetheeruptedvolumeandtoconstraintheeruptiondynamicsandevolutionwithtimeofthisuncommon,buthighlydangerous,typeofactivityofVillarricavolcano.

Basedon lithologicaland textural features,wedivided theChaimilladeposit into4maineruptionphases:Basal, Lower,MiddleandUpperphases,whichconsistofseveralunits(unitsA-J).Bothfalloutandpyroclasticdensitycurrentunitsarepresent.Thedispersalmapsofdifferenteruptiveunitsarecharacterizedbyaweakvariationonthedispersalaxis(beingtheunitCdispersedmainlynorthwardandtheunitHnorth-westward),suggestingachangeinwinddirectionduringtheerup-tion.WeestimatedtheeruptedvolumeofthemainfalloutunitsandourresultsindicatethatChaimilladepositwasgeneratedbyalarge-magnitudeeruption(VEI4).GrainsizedistributionofbothLowerandUpperfalloutsamplesshowaunimodaldistribution,rangingfrom-5Єto9Є,withthefraction>4Є(<63µm)always≤1wt%.UnitF(Middlephase)hasaslightlybimodalgrainsizedistributionandsignificantamountoffineash.SamplesfromtheBasalphasehaveinsteadastronglybimodalgrainsizedistribution,withapredomi-nanceof ash fraction. Juvenile componentpredominates inall theChaimilladeposit, and lithic contentdecreases frombottomtotopofthedeposit,suggestingthatthebeginningoftheeruptionwascharacterizedbytheopeningofaclosedvent.

WhilethegrainsizedistributionofLowerandUpperphaseofChaimillaeruptionisalwaysunimodal,densitydistributionofjuvenilesamplesshowsastrongbimodalcharacter,whosebimodalityishigherintheLowerphasewithrespecttotheUpperphase.Weidentifiedtwodifferentclastpopulations:population1isthelightestone,havingmodebetween1.0and1.2gr/cm3.Population2representsthedensestclastswithamoderangingbetween1.4and1.8gr/cm3.Clastmicrotextures

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tryaredifferentinthetwopopulations:clastsfrompopulation1havespherical-toirregular-shapedbubblesandmoderately

crystallizedgroundmass(~40vol%),whilepopulation2hasclastscharacterizedbystronglyirregulartocollapsedbubblesandhighlycrystallizedgroundmass(~60vol%).

Oureruptionmodelimpliesthearrivalofnewmagma(representedbyclastpopulation1)intoastagnant,degassedmagmabodywhichwasaccumulatedatshallowlevel(clastpopulation2).Thenewmagmabodyexsolvedvolatilesthatcouldnoteasilyescapethroughtheconduitduetopresenceofstagnantbody.Thiscausedgaspressuretobuildup,triggeringtheexplosiveeruption.Theeruptionstartedwithmultipleash-richexplosionsleadingtoventopening(Basalphase).Thefollow-ingLowerphasemarkedtheonsetofthefirsthighlyexplosivephaseoftheeruption,withfinalventopeningandcraterwidening,asmarkedbydecreasinglithiccontentfrombottomtotopofthedeposit.TheLowerphasedepositwasgeneratedbyapulsating,plumecolumn,whichinstabilitywasprobablyduetothelargeamountofthedenseclastpopulation2.TheplumecolumncollapsedcompletelyduringtheMiddlephase,whichisinfactcharacterisedbyseriesofpyroclasticdensitycurrentdeposits.WiththeoncomingoftheUpperphase,theplumecolumnbuiltupagainandremainedsustainedprodu-cingathickfalloutbedpredominantlyconstituedoflow-densityclastpopulation1.Theeruptionendedwiththickseriespyroclasticdensitycurrentswhichmarkedthetotalcollapseoftheeruptivecolumn.

REFERENCESClavero,J.&Moreno,H.2004.EvolutionofVillaricaVolcano,inVillaricaVolcano(39.5˚S),southernAndes,Chile.In:LaraLE,

Clavero JE (eds)VillarricaVolcano (39.5S) southernAndes,Chile.GobiernodeChile, ServicioNacionaldeGeología yMinería,pp17-27

Gurioli L,HarrisAJL,HoughtonBF, PolacciM,RipepeM (2008) Textural andgeophysical characterizationof explosivebasalticactivityatVillarricavolcano.JournalofGeophysicalResearch113:doi:10.1029/2007JB005328

WitterJB,KressVC,DelmelleP,StixJ(2004)Volatiledegassing,petrology,andmagmadynamicsoftheVillarricalavalake,southernChile.JournalofVolcanologyandGeothermalResearch,134,303-337

3.12

Pumice, a window into the volcanic conduit

DegruyterWim*,DufekJosef**,BachmannOlivier***,*

*Section des Sciences de la Terre et de l’Environnement, 13 Rue des Maraîchers, CH-1205, Genève (wim.degruyter@unige.ch)**School of Earth and Atmospheric Sciences, 311 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332 (USA)*** Department of Earth and Space Sciences, Mailstop 351310, University of Washington, Seattle, WA 98195-1310 (USA)

Tobetterunderstandpumicemicrotexturesandstressdistributionwithinthevolcanicconduit,anumericalstudyisper-formedusingpassivetracerstomapthetypeandamountofshearindifferentpartsoftheconduit.Duringanexplosiveeruptionpumicesare formedby fragmenting therisingmagmatic foam (i.e.highlyvesicularmagma).Provided theyarequenchedfastenough,pumicesreflectthestateofthemagmajustpriortofragmentationandtheirmicrotexturescarryinformationonthestressesappliedduringmagmaascent.Numerousdepositscontainbothtubepumice,withhighlyelon-gated vesicles and frothy pumice, with nearly spherical vesicles showing evidence that they were exposed to differentstressesduringmagmaascent (e.g.KosPlateauTuffandCampanianIgnimbrite).Themainaimofthis investigationistodeterminethestrainhistoriesofmagmaticparcelsthateventuallybecomepumice

WehavemodifiedtheMultiphaseFlowwithInterphaseExchanges(MFIX)codetosimulateatwo-phase(bubblesandmagma),two-dimensional, isothermalflowwithdisequilibriumbubblegrowth.Weincludearheologymodeldependingonwatercontentwithoutletexpansionintotheatmosphere.Furthermore,differentfragmentationcriteria(i.e.criticalgasvolumefraction,strainrateandgasoverpressure)areexamined.Strainhistoriesareinvestigatedbyreleasingpassivetracerswithinsimulatedmagmarise,whichrecordthepureandsimpleshearstrainratesduringascent.Therangeofaccumulatedstress-esatfragmentationshownbythepassivetracerscanthenbelinkedtotherangeofdifferentmicrotexturesfoundwithinpumices.

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Hornblende fractionation and peraluminous tonalite: an example of the Chelan Complex, Washington Cascades, USA

DessimozMathias*,OthmarMüntener*

* Institut de minéralogie et géochimie, Université de Lausanne, 1015 Dorigny (mathias.dessimoz@unil.ch)

OverthelastyearsnumerousexperimentalstudiesontheroleofH2Owereperformedtounderstandhowcrustaldifferen-

tiationoccursathighpressureunderwater (under)saturatedconditionssimilartowhatisexpectedinislandarcs.Theseexperimentsemphasizetheroleofsilicapoorphasessuchasgarnetandamphiboleathighpressureonthedifferentiationofbasalticmelt.HerewepresentresultsfromastudyontheChelanComplex(WesternU.S)toevaluatetheroleofhorn-blendeintheformationoffelsicplutonicrocks.TheChelancomplexisadeepplutoniccomplexexposedintheNorthCascadesCoreatthesouthernendofthenorthwesttrendingChelanblock.Itrepresentsoneofthedeeperexposures(30km)oftheCascadianarcandcouldthereforehelptoimproveourunderstandingofwhichprocessesoccurinthedeeppartofacontinentalarcandthefractionationprocessesofwetmaficmagmasathighpressure.

TheChelanComplexiscomposedbytonalite,gabbros,ultramaficrocksand“migmatite”.Fieldobservations,inparticularcomblayers,pegmatiticgabbrosandigneousbrecciasindicatethatthemagmaticoriginiswellpreservedalongtheentirecomplex.Whilesubsolidusdeformationoccurslocally,mostoftherocksaredeformedinpresenceofasilicatemelt,asin-dicatedbyapervasivemagmaticfoliationwelldevelopedinthetonaliteaswellassomeshearzonesfilledwithsillicicmeltandfewmagmaticfolds.

Thepressureofemplacementofthecomplexisbracketedbetween0.6Gpaand1.5Gpabythewidespreadoccurrenceofprimaryepidoteintonaliteandgabbrosandbytheabsenceofgarnet.However,theformationofpyroxenespinelsymplec-titesafterolivineandplagioclaseandAl-Tisystematicsinhornblendeindicateemplacementpressuresofabout1.0Gpafol-lowedbyisobariccoolingto700°Cat1.0Gpa.

Idiomorphicamphiboleandinterstitialplagioclaseingabbros,lackofnegativeEuanomalyinamphiboleandincreaseofZr/Tisuggestearlyamphiboleratherthanplagioclasefractionation.

Wholerockchemistryperformedonhornblendite,hornblendegabbros,diorite,tonaliteandmaficdykesdisplaycontinuoustrendsforvariousoxidesandarecoherentwithanevolutionthroughmagmaticprocesses.Thedifferentbehaviourofmajorelementscouldbereproducedsuccessfullybyasimplecrystalfractionationmodel,inagreementwithproportionandcom-positionofcumulatesobservedinthefield(ultramafic,hornblenditeandgabbros)andmineralcompositionmeasured.

Texturalobservations,modellingandresultsofhighpressureexperimentsindicatethathornblendeisthemainphasecon-trollingthedifferentiationoftheChelancomplexathighpressureandhighwaterpressure.Wehypothesizethatperalumi-noustonalitewithhighSr/Ycouldbederivedfromabasalticmeltbyhornblendefractionationandassimilationofcrustalmaterialisthusnotrequired.

3.14

Peridotites on Macquarie Island: evidence for anciently-depleted domains in the Earth's mantle pointing to global Proterozoic melting 'events'?

Dijkstra,ArjanH.*

*Institut de Géologie, d'Hydrogéologie et de Géothermie, Université de Neuchâtel, CP 158, 2009, Neuchâtel

Macquarie Island intheSouthernOcean isa fragmentofMioceneoceancrustunderlainbymantleperidotites thatwasupliftedandexposedabovesea-level.Petrologicalandgeochemicalanalysishasshownthatthemantlerocksaretoorefrac-torytobethesourceresidueoftheoverlyingcrustalrocks.Forinstance,theperidotitescontainessentiallynoresidualcli-nopyroxene,suggestingveryhighdegreesofpartialmeltingandmeltextraction.Meltingmodelsinvolvingtraceelementssuggestthattheperidotiteshaveseeninexcessof20%near-fractionalmelting.

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tryOsmiumisotopeanalysisofwholerocksamplesofperidotitesfromMacquarieIslandyieldedveryunradiogenic187Os/188Os

ratiosof0.1194-0.1229.Thesevaluesaremuchlowerthantypicalvaluesobtainedonabyssalperidotites.Theyindicatealong-livedRe-depletion.Re-depletionmodelagesareProterozoic(0.7-1.2Ga).TheseresultsconfirmthatthereisnosimplegeneticlinkbetweentheMiocenecrustandthemantlerocksexposedonMacquarieIsland,butthatthemantlerocksareafragmentofmantlethathasrecordedanoldmeltingevent,withoutanysubsequentrefertilization.

Ultra-refractoryperidotitesarealsoknownfromthe15-20°FractureZone(Mid-AtlanticRidge)andtheIzu-Bonin-Marianafore-arc,andtheyarefoundasxenolithsfrombeneathKerguelenIslandandHawaii.Inallthesecases,theultra-refractoryperidotitesalsogaveoldRe-depletionages.TheMacquarieIslandperidotitesareprobablysamplesofananciently-depleted,ultra-refractorymantlereservoirthathasglobalsignificance,butthathasgenerallybeenoverlookedsofarbecauseofitssterility,i.e.,itsinabilitytofurtherproducebasalt.

Themosttentativeaspectofthe,admittedlyverylimited,data-setofOsisotoperatiosofultra-refractoryperidotitesfromthelocalitieslistedaboveisthattheyseemtopointtotwoglobalmeltingeventsintheProterozoic,around0.8and1.2Ga(basedonRe-depletionages).Thepossiblegeologicalsignificanceoftheseeventswillbeexploredinmycontribution.

REFERENCESDijkstra,A.H.,Sergeev,D.S.,Spandler,C.A.,Pettke,T.,Meisel,T.,andCawood,P.A.Ultra-refractoryperidotitesonMacquarie

Island and the case for anciently-depleteddomains in the Earth'smantle. Accepted for publication in Journal ofPetrology,2009.

3.15

Sphalerite mineralisation in Bajocian shallow-water carbonates in the Swiss Jura Mountains related to extensional synsedimentary tectonics during the Middle-Late Jurassic.

NataliaEfimenko*,JorgeE.Spangenberg**,JensSchneider***,MassimoChiaradia****,ThierryAdatte*,VirginieMatera*****andKarlB.Föllmi*

*Institut de Géologie et Paléontologie, Université de Lausanne, 1015 Lausanne, Switzerland (natalia.efimenko@unil.ch)**Institut de Minéralogie et Géochimie, Université de Lausanne, 1015 Lausanne, Switzerland***Départment of Earth and Environmental Sciences, Katholieke Universiteit Leuven, Celestijnenlaan 200E, 3001 Heverlee, Belgium****Département de Minéralogie, Université de Genève, 1205 Genève, Switzerland*****Institut de Géologie et d’Hydrogéologie, Université de Neuchâtel, 2007 Neuchâtel, Switzerland

DisseminatedsphaleritemineralisationoccursinTriassicandJurassiccarbonatesintheSwissJuraMountains(e.g.Holenweg,1969;Hofmann,1989).Wereportnewresultsfromanongoingstudyoncadmium-rich(upto1.8wt.%)sphalerite(ZnS)foundinoolithiccarbonatesofBajocianageatLausen,AuensteinandPratteln(CantonBaselLand).Theseoolithiccarbonatesofthe“Hauptrogenstein”formationcontainelevatedconcentrationsofCd(upto21.4ppm;Rambeau,2006)andZn(upto207ppm;Jacquatetal.,2009).Weaimtounderstandhowthesemetalswereincorporatedintotherockandtheconditionsofsphalerite formation by using thin-sectionmicroscopy, XRD, ICP-MS, LA-ICPMS, EMP, cathodoluminescence, sulphur iso-topes,andRb-Sr/Pb-Pbisotopicdatingandtracing.CdandZnenrichmentsaremostlyassociatedwithpermeableoolithiccarbonatelithologies.HighconcentrationsofCdandZninlesspermeablerocks(marls,micriticcarbonates)appeartobefault-controlled.Forexample,inmarlybasinaldepositsoftheKlingnauFormation(coevalinagetotheHauptrogensteinformation)atHolderbank,Cdconcentrationsarelowat0,03ppmbutattainupto0.5ppmnearfaults.Likewise,Znincreasesfrom20to300ppmtowardsthesefaults.ThisCdandZnzonationsuggeststhatthecirculatingfluidswererichinCdandZncomparedtotheprimaryhostrock,andmainlyfo-cussedbyfaultssystemsorbypermeablerockunits.ThedistributionofZnandCdconcentrationsintheoolithiccarbonaterocksishighlyheterogeneous.Thisappearstoberelatedtoporositydifferences,andprobablytodifferenceinthedistributionofZn-andCd-bearingphaseswithintherock.Zincwasshowntobeassociatedwithcalcite,goethiteandsphalerite(Jacquatetal.,2009).Cadmiumismostlikelyadsorbedonto the surfaceofoolithic carbonategrains (Rambeau,2006), goethite, clayminerals, pyrite, andwithin the sphaleritecrystals.ThepreferentialcorrelationofCdwithZn incarbonaterockmayberelatedto thehighconcentrationofCd insphalerite.Nevertheless,CdconcentrationdoesnotsystematicallycorrelatewithZn.Thismaybeexplainedbythedifferentbehaviourof these twometalsduringtheir retentionontomineralphases (goethite,clayminerals,pyrite,carbonate).At

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y Lausen,Cdconcentrationdecreasesfrom12to0.03ppmandZnfrom2000ppmto12ppmwithinfewcentimetresfromreducedgreyportionstomorealteredyellowishpartsoftherock.Spaleritemicrocrystalsandframboidalpyritewereob-servedingreyunalteredparts.Nosphaleritewasobservedinthealteredrockportions,wherepyritewasoxidized.ThissuggeststhatCdandZnwereremobilisedduringtheweatheringprocesses.XRDanalysesofsphaleritecrystalsrevealedthepresenceofbothsphaleriteandwurtzite.TheexistenceofwurtziteindicatesbacterialactivityinvolvedinZnScrystallisationatlowtemperatures(lessthan60-80°).Thenegativeδ34Svaluesofsphalerites(–22.3to–5.3‰)pointtobacterialsulfatereduction(BSR)asthemainsourceofreducedsulfur.Acontributionofsulfidefromsedimentarypyritecannotbeexcluded.DirectRb-SrdatingofselectedsphaleritesamplesfromAuensteinyieldsanupperMiddleJurassic(Bathonian)isochronageof162±4Mawhichis interpretedtorecordsphaleriteformationduringaperiodofwidespreadtectonothermalactivityrelatedtotheopeningoftheNorthAtlanticandTethyanoceans.Thesesyn-sedimentarytectonicsalsoinfluencedthepale-otopography and facies distribution, which were spatially related to reactivated Paleozoic faults (e.g. Allenbach, 2001).Therefore,we propose amodel of cadmiumand zinc enrichment in the carbonate rocks by deep-sourced fluids duringmultistagetectonicprocessesintheregionrelatedtoanextensionalregimeduringtheJurassic.ThePbisotopiccompositionof sphalerite isveryuniform, indicatingan isotopicallywell-homogenized fluidsystem.ComparativePb isotopepatternsmaypointtoleadsourceslocatedingraniticandmetamorphicbasementrocksexposedinthesouthernBlackForestfarthernorth.Leadmayhavescavenged,mixedandhomogenizedfromPb-isotopicallydistinctcrystallinebasementrocktypesbyfluids during the Bathonian to yield a Pb isotope signature compatiblewith carbonated-hosted sphalerite in the SwissJura.Sphaleriteprecipitationmayberelatedtotheactivebacterialsulphatereduction.ThezonationofCdandZnincarbonaterocksseemstobecontrolledbythedistributionoffaciesandtheexistenceoffaults.DuringtheTertiary,tectonicactivityinJuraMountainsareamayhavetriggeredoxidativealterationofsulfides,formationofironoxy-hydroxides,andremobilisa-tionofCdandZn.

REFERENCESAllenbachR.P. 2001: Synsedimentary tectonics inanepicontinental sea: anew interpretationof theOxfordianbasinof

northernSwitzerland.EclogaeGeologicaeHelvetiae,94,265-287.Hofmann B. 1989: Erzmineralien in paläozoischen,mesozoischen und tertären Sedimenten derNordschweiz und

Südwestdeutschlands.Schweiz.MineralogischeundPetrographischeMitteilungen,69,345-357.HolenwegH.1969:MineralparagenesenimSchweizerJura.SchweizerStrahler,3,303-308.JacquatO., VoegelinA., Juillot F.&KretzschmarR. 2009:Chages inZn speciationduring soil formation fromZn-rich

limestones.GeochimicaetCosmochimicaActa,73,5554-5571.RambeauC.2006:Cadmiumanomaliesinjurassiccarbonates(Bajocian,Oxfordian)inwesternandsouthernEurope.PhD

thesis,UniversityofNeuchâtel,179p.(unpubl.).

3.16

Modeling the evolution of geothermal reservoirs in deep fractured rocks: Coupling chemistry to heat and fluid transport

HingerlFerdinandF.*,**,WagnerThomas**,KulikDmitriiA.*,KosakowskiGeorg*,DriesnerThomas**,ThomsenKaj***&HeinrichChristophA.**

*Paul Scherrer Institut, 5232 Villigen PSI, Switzerland, (ferdinand.hingerl@psi.ch)**Institute of Isotope Geochemistry and Mineral Resources, ETH Zurich, Switzerland***Technical University of Denmark, 2800 Kgs. Lyngby, Denmark

AconsortiumofresearchgroupsfromETHZurich,thePaulScherrerInstitut,EPFLausanne,andtheUniversityofBonn,cooperateintheCCESprogramGEOTHERM(www.geotherm.ethz.ch)aimedatperformingbasicresearchonkeyaspectsofEnhancedGeothermalSystems (EGSs).Our taskwithin theprogramconsistsofmodeling the fluid–rock interactionandscaleformationduringgeothermalheatextraction.Inparticular,wearedevelopingadvancedsoftwarethatshouldrealisti-callysimulatethelongterm(yearstodecades)evolutionofthepermeabilityandheatexchangeefficiencyinanEGSreser-voir.

Oursimulationsareanchoredontheoreticalinvestigationsoftheinterplayofchemicalprocesses(mineraldissolutionandprecipitationinrockfracturesandtechnicalinstallations)withtheflowofthereactivefluidthroughageometricallycom-plexandchangingfracturenetwork.Modelingofthisintegrativescenarioisperformedbycouplingachemicalequilibrium

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trysolverwithalgorithmsthatsimulatethemassandheattransportandgeometricalphenomena.Thechemicalsolversare

commonlybasedonaLaw-of-Mass-Action(LMA)method,whereasinourwork,thecomplementaryGibbs-Energy-Minimization(GEM)codepackageGEM-Selektor (http://gems.web.psi.ch) isused.GEMchemicalsolverscancomputephasespeciationinmorechemicallyplausiblesystemsthanitcanbedoneusingLMAsolvers,especiallywhenmanyhighlynon-idealsolutionsareinvolved.TheEGSreservoirischaracterizedbyvariable(uptohigh)salinityandelevatedtemperatureandpressure,whichisachal-lengeonthecalculationofaqueousspeciation.Forthisreason,inadditiontoseveralvariantsofDebye-Huckelequation,wehaveimplementedthePitzer(Harvieetal.1984)andtheEUNIQUAC(Thomsen&Rasmussen1999)aqueousactivitymodel,both applicable to mixed electrolyte systems at high ionic strength. Compared with the conventional Pitzer model,EUNIQUACrequiresfewerempiricalfitparameters(onlybinaryinteractionparametersneeded)andusessimplerandmorestabletemperatureandpressureextrapolations.Thisresultsinanincreaseincomputationspeed,whichisofcrucialimpor-tancewhenperformingcoupledlongtermsimulationsofgeothermalreservoirs.

Inordertosuccessfullyapplytheimplementedelectrolytesolutionmodels,wearecurrentlycompilingathermodynamicdatabaseandextenditwithrelevantPitzerandEUNIQUACparametersforcalculatingmineralsolubilityinawiderangeoftemperatures,pressuresandionicstrengthasapplicabletogeothermalfluids.WehavealsoimplementedtheSoave-Redlich-Kwong(Soave1972)andPeng-Robinson(PengandRobinson1976)equationsofstatefornon-idealgasmixtures,whichwillenablesimultaneouscalculationsofgassolubilityandboilingprocesses.

ThestandaloneGEMnumericalkerneloftheGEM-Selektorcode(abbreviatedGEMIPM2K)wasalreadysuccessfullycoupledto theThermo-Hydro-Mechanical (THM)codeGeoSys/Rockflow (Shaoetal.2009).FurthercouplingwiththeadvancedTHcodeCSMP++ (Coumou2008;http://csmp.ese.imperial.ac.uk/wiki/Home) is foreseenwithin theproject. Thenovel coupledcodesutilizingGEMIPM2Kwillbeusedwithinabenchmarkingstudy,testingtheefficiency,thenumericalstability,andthesensitivityoftheresultstodifferentnumericalproceduresandgeochemicalapproaches,lastbutnotnotleasttotheimpactofthechoiceofathermodynamicdataset.Astheconcludingstep,weintendtoconstructaconceptualmodelforthegeo-chemicalwater-rockinteractionprocessesincludingtheformationofmineralscalesandthecorrosionofpipesinwellsattheBaselEGSssite.

REFERENCESBruno J., BosbachD.,KulikD.,NavrotskyA. 2007:Chemical thermodynamicsof solid solutionsof interest in radioactive

wastemanagement:Astate-of-theartreport,ChemicalThermodynamicsSeries,10,Paris,OECD,266p.Coumou,D. , Matthäi, S., Geiger , S., and Driesner, T. 2008.Computers&Geoscience,Volume34,Issue12,pp1697-1707Harvie,E.H.,Moller,N.,Weare,J.H.1984.Thepredictionofmineralsolubilitiesinnaturalwaters:TheNa-K-Mg-Ca-H-Cl-SO

4-

OH-HCO3-CO

3-CO

2-H2Osystemtohighionicstrengthsat25°C.Geochim.Cosmochim.ActaVol.48,pp.723-751.

Karpov,I.K.,Chudnenko,K.V.,Kulik,D.A.1997.Modelingchemicalmasstransferingeochemicalprocesses:thermodynamicrelations,conditionsofequilibria,andnumericalalgorithms.AmericanJournalofScience297:767-806.

Karpov I.K.,Chudnenko,K.V.,Kulik,D.A.,Avchenko,O.V., andBychinski,V.A. 2001.MinimizationofGibbs freeenergy ingeochemicalsystemsbyconvexprogramming.GeochemistryInternational39,no.11:1108-1119.

Kulik,D., Berner,U., andCurti, E. 2004.Modelling chemical equilibriumpartitioningwith theGEMS-PSI code. In: PSIScientificReport2003 /Volume IV,NuclearEnergyandSafety (Eds.B.SmithandB.Gschwend), PaulScherrer Institut,Villigen,p.109-122.

KulikD.A. 2006a.Classic adsorption isotherms incorporated inmodern surface complexationmodels: Implications forsorptionofactinides.RadiochimicaActa94,no.9-11:765-778.

Peng,D.Y.,Robinson,D.N.(1976)Anewtwo-constantequationofstate.INd.Eng.Chem.Fundam.,15,59-64.Soave,G.(1972)EquilibriumconstantsfromamodifiedRedlich-Kwongequationofstate.Chem.Eng.Sci.27,1197-1203.Shao,H.,Dmytrieva,S.V.,Kolditz,O.,Kulik,D.A.,Pfingsten,W.,Kosakowski,G.2009.Modelingreactivetransportinnon-

idealaqueous-solidsolutionsystem.AppliedGeochemistry24,1287-1300.Thomsen,K.,Rasmussen,P. 1999.ModelingofVapor-Liquid-SolidEquilibria inGas–AqueousElectrolyte Systems.Chem.

Eng.Sci.,54,1787-1802.

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The mafic – granitic connection of the Torres del Paine laccolith, Patagonia

J.Leuthold1,O.Müntener1,L.Baumgartner1,B.Putlitz1,M.Ovtcharova2,UrsSchaltegger2,MassimoChiaradia2

1 IMG-UNIL, CH-1015 Lausanne, Switzerland (julien.leuthold@unil.ch)2 Mineralogy – UNIGE, CH-1205 Geneva, Switzerland

Wehaveconductedafield,petrologicalandgeochronologicalstudyofabimodalintrusivecomplexfromtheTorresdelPainelaccolith,Patagonia,Chile.Thegoalofthisstudyistounderstandhowvarioustypesofmaficrocksevolveatshallowpres-sureandhowtheyarerelatedinspaceandtimetothevariousgraniticsheets.Fromfieldrelationsitisevidentthatthegraniteintrudedasaseriesofsheets,withtheoldestpulseontopandtheyoungestatthebaseofthelaccolith.Highpreci-sionU-Pbdatingonsinglezircons(Micheletal.Geology2008)isinagreementwithfieldrelationsandyielded12.59±0.02fortheoldestand12.51±0.03fortheyoungestgranitedated.Thegranitesareunderlainbyaseriesofmaficsillscomposedofhornblende-gabbrosanddiorites.Wedistinguishtwotypesofhornblendegabbrosthatarechemicallysimilarbutclearlydifferentwithrespecttotheirmineralcrystallizationsequen-ce.However,thecontactsbetweenthedifferentmaficrocksareductileasillustratedbymaficenclavesindioriteorascentofsmalldioritediapirs intooverlayinghornblendegabbros, indicating (near-) simultaneousemplacementofmostof themaficrocks.Bulkrockchemistrysuggeststhatthemaficandgraniticrocksfollowahigh–Kcalcalkalinetoshoshoniticdifferentiationtrend.LiquidcompositionscalculatedfromLaserAblationICP-MStraceelementanalysisofcumulatemineralsindicatethatthemaficrockscrystallizedfromaK-richbasaltictoshoshoniticmagma.Intercumulusmineralsshowequilibriumwithagranodioritictograniticmelt,thatissimilartoPainegranites.Preliminaryisotopedilution–thermalionizationmassspec-trometryonzirconsfromonegabbroandonedioriteyielded12.40±0.04and12.447±0.013Ma,whichisabout60'000yearsyoungerthantheyoungestgranitedatedsofar.Thiswouldsuggestthatalargevolumeofthelaccolithgrowsdownwards,withyoungerandmoremaficsheetsatthebottomofthecomplex.Theyoungestgranitesthatcuttheentirecomplex,ho-wever,awaitprecisedating.

REFERENCESMicheletal.(2008),Geology36/6,459-462

3.18

Bromine speciation and partitioning in high pressure aqueous fluids and silicate melts: implication for the behavior of halogens in subduction zones

M.Louvel*,C.Sanchez-Valle*,W.J.Malfait*,G.S.Pokrovski**,C.N.Borca***,D.Grolimund***

*Institute for Mineralogy and Petrology, ETH Zurich, CH-8092 Zurich, Switzerland. (marion.louvel@erdw.ethz.ch)**CNRS, Laboratoire des Mecanismes et Transferts en Geologie, F-31400 Toulouse, France.***Swiss Light Source, CH-5232 Villigen PSI, Switzerland.

AlthoughhalogensareminorvolatilesintheEarth’scrust,theyareimportanttracersofmagmaticanddegassingprocessesand provide insights about subsurface magmamovement and eruption likelihood in subduction-related volcanism [1].Additionally,theirabilitytocomplexwithotherelementshasalsoconsiderableimplicationsontheformationanddistribu-tionoforedeposits[2].Prerequisiteforanefficientuseofhalogensasgeologicaltracersisanadequateknowledgeoftheirsolubilityanddistributionbetweenaqueousfluidsandsilicatemelts,aswellastheirspeciationinsubductionzonefluids.Experimentaldataonthesolubilityandfluid-meltpartitioningbehaviorofhalogensishoweverlimitedtopressuresbelow0.3GPa[3,4]andvirtuallynodataisavailableontheirspeciationinhigh-pressurefluids.Inordertoinvestigatethebehaviorofhalogensinsub-arcenvironments,X-rayabsorption(XAFS)andX-rayfluorescence(XRF)spectroscopymeasurementswereconductedinahydrothermaldiamond-anvilcell(HDAC-[5])upto850°Cand1.5(1)GPainBromine-richfluidsequilibratedwithsilicatemelts.BrominewasusedasananalogforchlorinesuitableforX-rayfluore-

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tryscencemeasurementsthroughthediamondwindowsoftheHDAC.ExperimentswereconductedattheX05-LAMicroXAS

beamlineoftheSwissLightSource(Switzerland).PressureinthesamplechamberwasmonitoredfromthePVTequationofstateofachipofgoldaddedtotheexperimentalvolume.Brfluid-meltpartitioncoefficientsinthehaplogranite-H

2Osystem

weredeterminedbyXRFspectroscopy.BrspeciationwasinvestigatedusingXAFSoverawiderangeofP-Tandbulkcomposi-tions, ranging frompureNaBraqueous solutions (3wt%Br) toalkali-SiO

2-rich solutions,water-saturatedNa

2Si

2O

5andha-

plogranititicmeltsandsupercriticalfluids(25wt%Na2Si

2O

5and10wt%haplogranite).

Thecombinedresultsoftheseexperimentsprovidevaluableinformationonthepartitioningbehaviorandstructuralenvi-ronmentofBrinhigh-pressurefluids.Brstronglypartitionsintotheaqueousfluidphase,inagreementwiththeresultsofBureauetal.[6]inquenchexperiments.PartitioncoefficientsDfluid/meltarecloseto25at650°C–1.0(1)GPabutdecreasewithincreasingP-T,asthesystemapproachesmiscibility.TheXAFSdatarevealchangesinthelocalstructurearoundBraschemi-calcomplexityincreasesinthesystemfromNaBrsolutionstoalkali-richSiO

2fluids,suggestingthecomplexationofBrwith

Na,SiandAl.TheimplicationsoftheseresultsforthebehaviorofBrandhalogensinsubductionzonefluidswillbedis-cussed.

REFERENCES[1]Aiuppaetal(2008),Chem.Geol.263,1-18.[2]Hedenquist&Lowenstern(1994),Nature370,519-527.[3]Webster(1992),Geoch.

Cosmo.Act.56,679-687.[4]Bureau&Metrich(2003),Geoch.Cosmo.Act.67,1689-1697.[5]Bassettetal(1993),Rev.Sci.Inst.64,2340-2345.[6]Bureauetal(2000),Earth.Planet.Sci.Lett.183,51-60.

3.19

Compositional dependent compressibility of dissolved water in silicate glasses revealed by Brillouin scattering on haplogranitic and basaltic glasses

WimJ.Malfait*,CarmenSanchez-Valle*,PaolaArdia*,**&EtienneMédard***

*Institute for Mineralogy and Petrology, ETH Zurich, CH-8092 Zurich (wim.malfait@erdw.ethz.ch)**Dept. of Geology and Geophysics, University of Minnesota, MN 55455 Minneapolis, USA ***Laboratoire Magmas et Volcans, Université Blaise-Pascal-CNRS, OPGC, F-63038 Clermont-Ferrand

Thedensityofhydrousmagmasisakeycontrolonthetimescalesandoutcomeofmanyigneousprocesses,e.g.thecrystalsettlingvelocitiesinamagmachamberandtheemplacementdepthofintrusions.Unfortunately,directdensitymeasure-mentsonhydrousliquidsatmagmatictemperaturesandpressuresareexperimentallychallengingandasaresult,veryfewexperimentaldataareavailable.Atatmosphericpressureandroomtemperature,thepartialmolarvolumeofwaterinsili-categlassesandmeltsseemstobeindependentofthebulkcompositionoftheglass(RichetandPolian,1998).Encouragedbythisconstantpartialmolarvolumeatroomconditionsandbecauseofthelackofsufficientexperimentalconstraints,currentdensitymodelsforhydrousmagmaticliquids(e.g.OchsandLange,1999)assumethatthepartialmolarvolumeofthedissolvedwaterathightemperatureandpressureisalsoindependentofmeltcomposition.Thisassumption,however,hasneverbeenexperimentallyconfirmed.

Inordertoverifyifthepartialmolarvolumeofwaterremainsindependentofmagmacompositionatelevatedpressures,wehavedeterminedthesoundwavevelocitiesandbulkmodulus(K

S)ofaseriesofhydroushaplograniticandbasalticglasses,

quenchedatdifferentpressures,usingBrillouinspectroscopy.Thecompressionalwave(VP)andshearwavevelocities(V

S)sy-

stematicallydecreasewiththeadditionofwater.ThepartialmolarKSofwater,andhencethecompressibility,isdifferent

fordifferentmagmacompositions.This implies that thepartialmolarvolumeofwaterwillnotbe independentofmeltcompositionatelevatedpressure.TheseresultssuggestthatthedensitymodelofOchsandLange(1999)mayhavelimitedapplicabilityatelevatedpressure.Thedevelopmentofmorerobustdensitymodels forhydrousmagmatic liquidscannotproceeduntiladditionalinsitu,highpressureandtemperaturemeasurementsofmeltdensity,thermalexpansionand/orcompressibilityareavailable.

REFERENCESOchs,F.A.,andLange,R.A.(1999)Thedensityofhydrousmagmaticliquids.Science,283,1314.Richet,P.,andPolian,A.(1998)Waterasadenseicelikecomponentinsilicateglasses.Science,281,396-398.

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PVTx properties of high pressure aqueous fluids by Brillouin scattering spectroscopy

MantegazziDavide*,Sanchez-ValleCarmen*,ReusserEric*,DriesnerThomas**

*Inst. for Mineralogy and Petrology, ETH Zurich, CH-8092 Zurich, (davide.mantegazzi@erdw.ethz.ch)** Inst. of Isotope Geochemistry and Mineral Resources, ETH Zurich, CH-8092 Zurich

AqueousfluidsplayaveryimportantroleinmanygeologicalprocessesintheEarth’scrustandmantle.Typicalexamplesoffluidmediatedgeologicaleventsare:themagmaproductioninthemantlewedgebeneathactivevolcanoesatsubductionzones,metamorphicreactionsinvolvingfluidphases,thehydrothermalalterationoftheseafloor,thetransportofchemicalcomponentsandtherelatedoredepositsformation.

StudiesonFluidInclusions(FI)havepointedoutthatfluidsintheternarysystemH2O–NaCl–CO

2canbeconsideredasgood

approximationfornaturalgeologicalfluids.

Inordertoquantitativelymodelfluid-rockinteractions,thermodynamicdataonmineralsandfluidsatgeologicallyrelevantP-Tconditionsarenecessary.Whilethesedataareavailableforthemostrock-formingminerals,thisisnotthecaseforaque-ousfluidsdifferentthanpureH

2O.Forexample,theequationsofstate(EoS)ofH

2O–NaClfluidsarerestrictedto0.5GPa.

Therefore,theinterpretationoffluidrelateddeepgeologicalprocessesrequirestheextrapolationofthermodynamicproper-tiesoveranorderinmagnitudeinpressure.Inaddition,theknowledgeofthethermodynamicpropertiesoffluidsintheternarysystemH

2O–NaCl–CO

2isessentialforunderstandingandmodelingtheFIdata.

InthiscontributionwepresentthePVTxpropertiesofdifferentaqueousfluidsuptohighP-Tconditions,calculatedfromsound velocitymeasurements using Brillouin scattering spectroscopy. All experimentswere conducted in an externallyheatedmembrane-typediamondanvilcell(mDAC).

Brillouinscatteringspectroscopyallowsthedirectmeasurementofthevelocityofacousticwavespropagatinginamaterial(fluidorsolid).ThecollectedsoundvelocitiesV

PareusedtodeterminetheEoSЄ(P,T,x)oftheanalyzedfluids.

TheresultsarecombinedwithpreviousexperimentalandtheoreticalEoStoobtainacontinuousmodelfromlowtohighP-Tconditions,providingadatabaseforthethermodynamicpropertiesofthemostrelevantaqueoussystemsinvolvedinfluid-mediatedgeologicalprocesses.Figure1showsthecomparisonbetweentheEoSЄ(P,T,x)ofdifferentH

2O–NaClmixtures.At2GPathesolutionwith5.5wt%

NaClis5.2%denserthanpurewater,whileat3GPathesolutionwith14.9wt%NaClis9.6%denserthanwater.Withincreas-ingpressurethedifferenceindensitybetweenwaterandchloride-richsolutionsisincreasing.

REFERENCESAbramson,E.,&Brown,M.J.2004:Equationofstateofwaterbasedonspeedsofsoundmeasuredinthediamond-anvilcell.

Geochim.Cosmochim.Acta68,1827-1835.Driesner,T.2007:ThesystemH2O-NaCl.PartII:Correlationsformolarvolume,enthalpy,andisobaricheatcapacityfrom0

to1000degreesC,1to5000bar,and0to1X-NaCl.Geochim.Cosmochim.Acta71,4902-4919.Sanchez-Valle,C.,&Bass,J.D.2007:Equationofstateoffluidsfromsoundvelocitymeasurementsinthediamondanvilcell

usingBrillouinscatteringspectroscopy.Geochim.Cosmochim.Acta71,A873-A873.Wagner,W.,&Pruss,A.2002:TheIAPWSformulation1995forthethermodynamicpropertiesofordinarywatersubstance

forgeneralandscientificuse.J.Phys.Chem.Ref.Data31,387–535.

Figure1.EoSЄ(P,T,X)forH2O–NaClmixtureswithdifferentsaltconcentrationsasafunctionofpressurealongthe200°Cisotherm.All

theseEoShavebeendeterminedwiththesameexperimentaltechnique.Dataforthe14.9and5.5wt%NaClsolutionsarefromthiswork;

densitiesforthe0wt%NaClmixturearetakenfromSanchez-ValleandBass(2007).

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3.21

Evidence of Jurassic rifting in the Dent Blanche nappe (near Cignana, Italy)

PaolaManzotti*,DanieleRegis*,BenedicteCenki-Tok*,MartinRobyr*,TonnyB.Thomsen*,DanielaRubatto**,MicheleZucali***&MartinEngi*

*University of Bern, Baltzerstrasse 1+3, 3012 CH-Bern (manzotti@geo.unibe.ch)**The Australian National University, Mills road, Canberra, ACT, 0200 Australia***Dipartimento di Scienze della Terra «Ardito Desio», Università degli Studi di Milano, via Mangiagalli 34, 20133 I-Milano

TheRoisanZoneisconsideredtobetheMesozoicmetasedimentarycoveroftheDentBlanchenappe(Austroalpinedomain,WesternItalianAlps;Diehletal.,1952).Itisdismemberedintometrictohectometricbandsandpodsofmarbles,dolomiticbrecciaswithaphylliticmatrix,calcschist,micaschist,chloriteschist,impureandmanganoanquartzites.

IntheRoisanZonewefoundtheAlpinerecordtobeheterogeneous;themetamorphicimprintindicateslowtemperatureandintermediatepressure,locallythisisassociatedwithsuperimposedmyloniticfoliations.Fourevolutionarystageshavebeenreconstructedbymeso-andmicrostructuralanalysis.Pre-stage1isapre-Alpineeventrecognisedonlyatthemicroscale.Duringstage1awelldifferentiatedmillimetricfoliationdevelops,whereasD2structuresconsistofisoclinicalfolds,trans-posingtheS1foliationintoanew,pervasiveS2.D3structuresmainlyconsistofisoclinalfolds:thisstageisnotalwaysas-sociatedwiththedevelopmentofanewfoliation.

WithintheRoisanZone,particularlynearCignana,weinvestigatedcross-cuttingrelationshipsbetweenmetamorphicanddeformationalsignatures.InMn-quartziteandmarblearelativetemporalsequencewasdeduced.Titaniteandallaniteweresingledout forU-Th-Pbdating.Allanite fromMn-quartzitesoccursas subhedralcrystalsanddisplays irregularzoning inLREE,Ca,Fe,andMg.SHRIMPandLA-ICP-MSanalysesdidnotyieldthemetamorphicAlpineageexpectedonthebasisofpetrographicandstructuralobservations.TheanalyzedgenerationofallanitegrainsshowsPermianages(between350and290Ma).

Titaniteinmarbleoccursasabundantsubhedraltoanhedralcrystals(mostlyfracturedand/ordeformed),locallysub-paralleltothefoliation.BSEimages,qualitativeX-rayelementalmaps,andEMPspotanalysisshowweakregulartoirregularzoninginAl,TiandCa.SHRIMPU-PbanalysisoftitanitedomainswithvariousAlcontentsyieldapparentspot206Pb/238Uagesscat-teringbetween284and160Ma.

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y TheyoungeragesoftitanitearetentativelyinterpretedasreflectinganextensionalregimethatprecededtheAlpinecolli-sion.FurtherworkisunderwaynowtoclarifywhetherzoningofLREE,Ca,FeandMginallaniteandvariationsofAl,TiandCaintitanitegrainsmaypartlyreflectchangesinfluidcompositionsinametasomatic-hydrothermalsystemassociatedwithextension,possiblyinanoceanicenvironment.

REFERENCESDiehl,E.A.,Masson,R.,Stutz,A.H.1952:Contributoallaconoscenzadel ricoprimentodellaDentBlanche.Memoriedegli

IstitutidiGeologiaeMineralogiadell’universitàdiPadova17,1-52.

3.22

Ore fluid evolution in a volcanic-hosted epithermal ore deposit: Farallón Negro, Argentina.

Márquez-Zavalía,M.Florencia*,Heinrich,ChristophA.**,Meier,Dimitri**

*IANIGLA, CCT Mendoza, CONICET, CC 330, (5500) Mendoza, Argentina (mzavalia@mendoza-conicet.gov.ar)**Isotope Geochemistry and Mineral Resources, Federal Institute of Technology, ETH Zentrum NO, CH-8092, Zurich, Switzerland

TheFarallónNegromineraldepositislocatedinCatamarcaprovince,Argentina,at27º19´Sand66º40´W.Thislowsulfida-tionepithermalgolddepositbelongstotheFarallónNegrominingdistrict,alongwithotherepithermal (e.g.,Capillitas,CerroAtajo)andporphyrydepositssuchasBajodelaAlumbreraandAguaRica.ThisclusterofCu-AumineraldepositsaregeneticallylinkedtoaMiocenevolcaniccomplexwithasuiteofrocksofhigh-Kcalk-alcalinetoshoshoniticaffinitiesknownasFarallónNegroVolcanicComplex(FNVC).Manyauthorsinterpretedthewholecomplexastheremnantofalargeandesiticvolcano(e.g.,Halteretal.,2004;Proffett,2003;Ulrichetal.,2002;andreferencestherein),thoughHarrisetal.(2006)presentsomecontradictingevidences.

AltodelaBlendaarea,wherethisstudywasfocused,isoneofthetwomainsuitsofveinsoftheFarallónNegromineraldeposit.ThemainveinsofAltodelaBlendaare:Laboreo,EsperanzaandEsperanzaSE.TheWpartofLaboreoveinishostedinandesiteandtherestofthatveinandtheothertwoarehostedinmonzonite.Theyaremorethan1000mlong,1to6mwide,withgradesupto7g/tAuand200g/tAg(Montenegro&Morales,2004).

Therewererecognizedfourstagesofthemineralizationwith7generationofquartz.Stage Iisrepresentedbytheearliestquartzrecognized(Q1)inthedeposit,presentasfragmentsinabreccia,itisbluishgreyincolourandoccursalongwithfragmentsofwhitishcarbonate(Cb1)andscarcedisseminatedpyrite.Stage IIcorrespondstothebreccia,whichiscementedbyasecondgenerationofquartz(Q2),greyincolour,interlayeredwithbandsofcreamycarbonate(Cb2)andassociatedwithfreeAu,sulphides(pyrite,galena,chalcopyrite,sphalerite)andCu,Ag,AuandPbsulphosalts.Attheendofthisstage,quartz(Q3)incolourlesscrystalsupto1cmlongfillstheremainingopenspacesandvugs.Stage IIIisrepresentedbyayoungergenerationofgreyquartz(Q4),associatedwithpinkandyellowishcarbonate(Cb3)andchalcopyriteandAgminerals.Itoc-cursparallel to thebreccia and frequently crosscutting it.At the endof this stage, small cavities are filledwithquartzcrystals(Q5)thatfrequentlydevelopalayeredbaseonwhichgrowtransparent,colourlesscrystalsupto2cmlong,develo-pingcombtextures.Insomeareas,Stage IVispresent,wherethelasttwogenerationsofquartzcanberecognized.Thefirstone(Q6)isscarceandoccurswithwhite(andpink?)layeredcarbonate(Cb4),mostlyoxidized(cryptomelaneandpyrolusite>>manganite,manjiroiteand“wad”)andgalena,chalcopyriteandsphaleritegenerallyscarce.SometimestheassociationQ6+Cb4isparalleltothewholesequenceandothertimescrosscutsit.Theyoungestquartz(Q7)fillstheopenspacesanddevelopscolourlesscrystalsupto1cmlong.Inseveralareasofthedeposit,localizedbrecciationaffectsdifferentpartsofthesequence.Preliminaryfluidinclusionresultsgiverangesofhomogenizationtemperaturesfrom200to270ºC,andsalinitiesfrom3.40to4.70NaClequiv.forEsperanzaveinandsimilarhomogenizationtemperaturesbutlowersalinitiesforLaboreovein.ThefirstresultsofmicroanalysesbyLA-ICPMS,performedinprimaryaqueousfluidinclusionstrappedinquartz,showconcen-trationsofppm-levelsofAuandhundredsofppmofCu.ThehighestvaluesofAuconcentrationswerefoundinQ2andQ3,belongingtothesecondstageofthemineralization,whilethehighestCuvaluescamefromsampleswithQ6andQ7,corre-spondingtothelaststageofthemineralization(StageIV).Otheroreformingelementswerealsoanalyzedandallresultswillbeinformedindetailwhenthestudyiscompleted.Therewereaswellinvestigatedtheaqueousfluidsofthelateveins,withAu-Ag-bearingquartz+Mn-carbonate+base-metalminerals,foundintheBajodelaAlumbreraopenpit(Meier,2008;Meieretal.2008)Thoughtheresultsarestillpreliminary,theresearchinprogressshowsthefirstsalineepithermalfluidsinalow-to

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tryintermediatesulfidationepithermalsystemcontainingsignificantlyhighermetalconcentrationsthanfluidsinanyactive

geothermalsystem(e.g.,SimmonsandBronwn,2006).Theseveryhighmetalconcentrations(ppm-levelsofAuandhundredsofppmofCu)inthefluidindicatethatevenlow-tointermediate-sulfidationeconomicveindepositsdonotformfromcon-vectinggroundwateralone,butfrominjectionofvapor-derivedmagmaticfluid.

REFERENCESHalter,W.E.,Bain,N.,Becker,K.,Heinrich,C.A.,Landtwing,M.,VonQuadt,A.,Clark,A.H.,Sasso,A.M.,Bissig,T.&Tosdal,R.M.

2004:FromandesiticvolcanismtotheformationofaporphyryCu-Aumineralizingmagmachamber:theFarallonNegroVolcanicComplex,northwesternArgentina:JournalofVolcanologyandGeothermalResearch,136,1-30.

Harris,A.C.,Bryan,S.E.&Holcombe,R.J.2006:VolcanicsettingoftheBajodelaAlumbreraporphyryCu-Audeposit,FarallonNegroVolcanics,NorthwestArgentina:EconomicGeology,101,71-94.

Meier,D.2008:LowsalinityfluidsattheBajodelaAlumbreraporphyryCu-Audeposit,Argentina.MScthesis.Inst.IsotopeGeochemistryandMineralResources,Dept.EarthSc.,ETH-Zürich,SwissFederalInstituteTechnology.

Meier,D.,Heinrich,C.A.,Guilong,M.&Márquez-Zavalia,M.F.2008:LowsalinityfluidsattheBajodelaAlumbreraporphyryCu-Audeposit,Argentina.SwissGeoscienceMeeting.

Montenegro,N.&Morales,F.2004:DistritomineralizadoFarallónNegro.YMAD,Belén,Catamarca,Argentina.In:Márquez-Zavalía,M.F.(Ed.)CursoLatinoamericanodeMetalogeniaUNESCO-SEG2004.GuíadeCampo:83-99.

Proffett, J.M.2003:Geologyof theBajode laAlumbreraporphyrycopper-golddeposit,Argentina:EconomicGeology,98,1535-1574.

Ulrich,T.,Günther,D.&Heinrich,C.A.2002:TheEvolutionofaporphyryCu-Audeposit,basedonLA-ICP-MSanalysisoffluidinclusions:BajodelaAlumbrera,Argentina:EconomicGeology,97,1889-1920.

Simmons, S.F.&Bronwn,K.L. 2006:Gold inmagmatichydrothermal solutions and the rapid formationof a giant oredeposit.Science,314,5797,288-291.

3.23

Baggalútar from Hvalfjörður, SW Iceland: Volcanic spherulites or not?

MattssonHannesB.*,ReusserEric*

*Institute for Mineralogy and Petrology, Department of Earth Sciences, ETH Zürich, Clausiusstrasse 25, CH-8092 Zürich (hannes.mattsson@erdw.ethz.ch)

Baggalútarformwell-roundedspherules,rangingbetween0.5-3cmindiameter,andoccureitherassinglespherulesorag-gregatescontainingupto10individualspherulesjoinedtogether.TheyarerelativelycommononbeachesalongtheAtlanticcoast in HvalfjörЄur (SW Iceland).In literature, Baggalútar have commonly been explained as being volcanic spherulites(SaemundssonandGunnlaugsson,1999).However,Baggalútarlacktheinternalstructurecharacteristicforvolcanicspheru-liteswhichcommonlyinvolvesradialgrowthoffeldsparandquartzneedlesassilicicglassdevitrifies.Theyarenotaccretion-arylapilliasthesecommonlyformbyaccretionoffineasharoundanucleiiinanonion-liketexture.Neitheraretheycon-sistentwithbeingmarineconcretions,whicharecharacterizedbyconcentricinternaltextures.

Inthinsection,onlyrandominternaltexturecanbeobservedandtheBaggalútariscomposedofafine-grainedgroundmasswithabundantroundedvoidswhichhavebeeninfilledwithsecondaryminerals(mainlythomsonite,heulanditeandnatro-lite).XRDandSEManalysesshowthatthegroundmassiscomposedoflath-shapedplagioclase(An-rich),augiticclinopyrox-eneandtitanomagnetiteinvariousproportions(Fig.1).TheoverallmineralogyoftheBaggalútaristhereforeconsistentwithbeingbasaltic.Furthermore,theinternaltexturesuggeststhatitcouldbebasalticash,inwhichthevesicleshavebeenin-filledbyzeolitemineralsatalaterstage.

However,afewthingsabouttheoccurrenceofBaggalútarremainenigmatic:

1.Absenceofphenocrysts.Infiveinvestigatedthinsectionsonlytwosmallclinopyroxenephenocrystscouldbefound,andallspheruleshaveafine-grainedhomogeneoustexturestronglyreminiscentofquenching.

2.Whatcausesthewell-roundedshape?Thisisincontrasttotherandomlyorientedinternalstructureofthespherules.IfonlysingleBaggalútarareconsidered,theirwell-roundedshapescouldpotentiallybeattributedtomarineabrasion.However,thisdoesnotexplaintheoccurrenceofmulti-spheruleaggregatesinwhicheachspheruleiswell-rounded.

3.Wheredotheycomefrom?SofarnooutcrophasbeenfoundinHvalfjörЄurinwhichtheBaggalútaroccursinsitu,andfindingsuchanoutcropmayhelptoshedlightontheirformation.

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y REFERENCESSaemundsson,K.&Gunnlaugsson,E.1999:Islenskasteinabokin,MalogMenning,Reykjavik,pp.233.

Fig.1.CharacteristicsofBaggalútaratdifferentmagnifications.(a)Acollectionofhandspecimens.(b)SEMimageshowinghomogeneous

internaltexturewithvesiclesinfilledbyzeolites.(c)Close-upSEMimageofthegroundmasscomprisingplagioclase(lath-shaped,dark),

clinopyroxene(grey)andtitanomagnetite(white).

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Columnar jointing and the formation of “chisel-marks” in the Hrossadalur lava flow, northern Iceland

MattssonHannesB.*,BosshardSonja*

*Institute for Mineralogy and Petrology, Department of Earth Sciences, ETH Zürich, Clausiusstrasse 25, CH-8092 Zürich(hannes.mattsson@erdw.ethz.ch)

Columnarjointingand“chisel-marks”arecommonfeaturesinthick,slowlycooled,basalticlavas.Thefracturingtoformcolumnarjointingiscommonlyattributedtothermoelasticstraincreatingalocaltensilestress,whichresultsintheforma-tion of joints organized into columnswith a polygonal cross-section and large aspect ratio (length/diameter).The chiselmarks,ontheotherhand,arestriaeorientedperpendiculartothemainaxisofthecolumnandreflectsastepwisecrackpropagationasthelavascool.

Fig.1.Schematicsketchofcolumnarjointingandchisel-marksintheHrossadalurlavaflow.Hammerforscale.

AtHrossadalurinnorthernIcelanda200mlongcross-sectionofaponded,columnar-jointed,basalticlavaflowisexposedinanormalfaultbelongingtothemuchlargerKraflafissureswarm.ThetotalthicknessoftheHrossadalurlavaflowexceeds10m,anddisplayaninternalmorphologycharacteristicforp-typepahoehoewithavesicularuppercrustandadenseinte-rior.Closetothetopofthelavaflowsmall-scalecolumnarjointingisabundant(althoughpoorlydeveloped).Inthispartoftheflowchiselmarksareabsent.Startingroughly0.8-1.5mfromthetopoftheflow(i.e. thecoolingsurface),columnarjointsarefewerandlargerinsizeandchisel-marksstarttoform(Fig.1).Theinitialspacingbetweenindividualchiselmarksissmall(afewcm).However,thespacingofthechisel-marksshowsasystematicincreasewithdepthintotheinterioroftheflow(incasesexceeding25cmnearthecentralpartoftheflow).Thebaseoftheexposedsectioniscomposedofamassivepart,wherecolumnarjointingandchiselmarksareabsent.Insteadconcentricarrangementofvesiclesandflowfoliationindicatethatthisportionofthelavaflowwasoccupiedbylavatubes.

Measurementsofthespacingofchisel-marksatHrossadalur,incombinationwithobservationsofcrackpropagationinac-tiveHawaiianlavaflows(Honetal.,1994),suggeststhatthespacingrepresentstheeffectivethicknessoftheviscoelasticpartofthecrustasalavaflowprogressivelycoolsandsolidifies.Thefracturepropagationisincremental,goingfromthebrittlecrust(<800°C),throughtheviscoelasticlayer(800-1070°C),tothemolteninterior(>1070°C).Afteronestepoffracturepropa-gation,theflowneedstocooltobuildupsufficientthermoelasticstraintopromoteanothercycleofcrack-propagation.

Tentativemodelingofconductivecooling(CarslawandJaeger,1959)involvingachangeofstate(moltentosolid),showsgoodagreement between the time-dependant thickness of viscoelastic crust and the measured spacing of chisel-marks atHrossadalur.Thus,thespacingofthechiselmarkspresentincolumnarjointedbasaltscaneffectivelybeusedtoconstrainthecoolinghistoryofslowlysolidifyinglavalakesandintrusionsaswellaslavaflows.

REFERENCESCarslaw,H.S.&Jaeger,J.C.1959:Conductionofheatinsolids,2ndEd.,OxfordUniv.Press,NewYork,pp.510Hon,K.,Kauahikaua,J.,Denlinger,R.&MackayK.1994:Emplacementandinflationofpahoehoesheetflows:Observations

andmeasurementsofactivelavaflowsonKilaueavolcano,Hawaii,GeologicalSocietyofAmericaBulletin,106,351-370.

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Convective instabilities in Volcanic Clouds

MonnardHélène*,ManzellaIrene*,JeremyPhillips**,CostanzaBonadonna*

*Department of Mineralogy, University of Geneva, Rue des Maraîchers 13, CH-1205 Genève (hmonnard@gmail.com)**Department of Earth Sciences, Centre for Environmental and Geophysical Flows, University of Bristol, UK

Convectiveinstabilitiesdrivenbyparticlesedimentationmayplayanimportantroleintheparticledispersalfromvolcanicplumes (e.g.Figure1).Such instabilitiesoccur indensitystratified fluidsandtheyarecharacterisedbythe formationoffingers.Whenaparticle ladenfluidissituatedaboveadenserfluid,thetwolayersareinitiallystable.Withtheparticlesettling,athickeninginterfacelayerbecomesgravitationallyunstableandfingerscouldstartdevelop.Manyexperimentshavebeencarriedouttocharacterizethisprocess (e.g.Chen1997;Hoyaletal.1999;Völtzetal2000).However,notmanyexperimentswerecarriedouttoinvestigateconvectiveinstabilitiesinavolcanicsetting(e.g.Carey1997).Inaddition,numericalmodelsusedtodescribetephradispersaldonotaccountforconvectiveinstabilities.Wehaveperformedlaboratoryexperimentstoinvestigatethedynamicsofthisphenomenonanditseffectsontherateofparticlesedimentationfromthebottomofthevolcanicplumeanddepositionatthebed.

TheexperimentswerecarriedoutinaPlexiglastankofasizeof30cmwidthx7.5cmdepthx50cmheight(seeFigure2a),wherearemovableandflexiblePETsheetisplacedat25cmheighttoseparatetwodifferentlayersoffluidandensureaninitiallysharpinterface.Theupperpartisfilledupto13.5cmwithalightersuspensionofwaterandparticles,thelowerpartisfilledwithadensersugarandwatersolution.Theupperlayerisstronglymixedbeforeeachexperimenttoensureaninitiallyuniformconcentration.Experimentsconsist inremovingtheseparationandanalyzingtheformationof fingers.EachexperimentisfilmedbyaHDcamera.Aprocessofcalibrationhasbeencarriedouttocorrelatethedifferentgreylevelsofafilmimagetodifferentlevelofconcentration.

Aftertheremovaloftheseparation, ifweconsidertheupperlayertobehaveasasimplequiescentsuspension,wecouldexpectitsmeanconcentrationtodecreaselinearlywithtimeasfollows:

)( 00 h

twCCtC s−=

Preliminaryobservationsshowedusthatthis isnotthecaseforourexperiments (seeFigure2b).Asamatteroffact,theconcentrationvaluesstartdecreasingafteracertaintimefollowingtheopeningoftheseparation.Thiscouldbeduetothefactthatthelinearmodeldoesnottakeintoaccounttheaccumulationofparticlesattheinterfacebetweenthetwolayersatdifferentdensities,whichactuallycausesgravitationalinstabilities.Thesefirstconsiderationsconfirmthefactthatcon-vectiveinstabilitiesinfluencetherateofsedimentationandconsequentlyunderlinetheneedtodevelopnewandcompleteanalyticalexpressionstoimprovemodellingofsedimentationfrombuoyantplumes.

Figure1:Examplesoffingeringgeneratedatthebaseofhorizontally-spreadingvolcanicclouds(EruptionofMontserrat,1997.Photoby

CostanzaBonadonna).

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Figure2:(a)Theexperimentalset-up,aPlexiglastankof30x7.5x50cmafterthebannerisremoved.(b)Meanconcentrationfortheupper

layerasafunctionoftimeforaninitialconcentrationof4.9g/Lcomparedwiththelinearmodel.

REFERENCESCarey,S.N.1997:Influenceofconvectivesedimentationontheformationofwidespreadtephrafalllayersinthedeepsea.

Geology,25(9),839-842.Chen,C.F.1997:Particlefluxthroughsedimentfingers,DeepSeaResearchPartI.OceanographicResearchPapers,44(9-10),

1645-1654.Hoyal,D.C.J.D.,etal.1999:Settling-drivenconvection:Amechanismofsedimentationfromstratifiedfluids.J.Geophys.

Res.,104.Voltz,C.,etal.2000:Finger-likepatternsinsedimentingwater-sandsuspensions.PhysicsReports,337,117-138.

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Geochemical constraints on the development of a Mesozoic volcano- tectonic arc and fore-arc basin in the Sanandaj-Sirjan Zone, south Iran

MonsefIman*,RahgoshayMohammad*,EmamiMohammad-Hashem**&ShafaiiMoghadamHadi***

*Shahid Beheshti University, Faculty of Earth Sciences, Tehran, Iran (iman_monsef@yahoo.com)**Research Institue for Earth Sciences, Geological Survey of Iran, Teharn, Iran***Damghan University of Basic Sciences, School of Earth Sciences, Damghan, Iran

ThetectonichistoryoftheNeo-TethyanregioninIranwasbegunbythecreationoftheoceaniclithospherewithriftingbe-tweentheCentralIranianBlockandGondwana(Arabia)duringLatePermian-EarlyTriassictime.ThesubductionoftheNeo-TethysstartstothesouthoftheCentralIranianBlockatLateTriassic–LateJurassictime.Thissubductionphaseledtopres-ence of volcanic activities and emplacement of intrusive bodies within the Sanandaj-Sirjan Zone (Fig. 1). Therefore theSanandaj-SirjanZonebehavedasanactivecontinentalmargin,witnessbythepresenceofcalc-alkalinearc-relatedmagma-tism.TheSanandaj-SirjanMagmaticArciscomposedmainlyofaMesozoicmagmatismincludinglava(basalt,andesiteanddacitictuff)andplutonicrocks (granite,granodioriteandquartzmonzonite),alternatingwithlimestonesandOrbitolinalimestone.

AboutasametimeduringsubductionoftheNeo-Tethys,riftingalongtheSanandaj-SirjanZonetookplace,resultinginopen-ingofaLateTriassictoEarlyJurassictranstensionalfore–arcbasincalledtheHajiabad–EsfandaghehColorMelangeZone(Fig.1).Thiszonecontainsabundantultramaficswithchromitedeposits,partlypreservedvolcano–sedimentarysequenceswithpillow lavas,Globotruncana–bearing redmarls and radiolarites, and exoticmarbles, amphibolites andminor blueschists.Volcanicrockshaveamixtureofdominantlyarc-like(calc-alkaline)andsubordinateMORB-likecompositionalfeatures.

TheemplacementofColorMelangeZonetookplaceduringtheEarlytoLateCretaceousasaresultofcollisionalandconti-nental subduction of theGondwana (Arabia) beneath theCentral IranianBlock along theMain Zagros Thrust Belt. TheZagrosorogenisayoungTertiarycollisionbeltgenerallyconsideredarecentanalogueoftheHimalayanorogenicbelt.

Figure1.SimplifiedstructuralsketchmapofsouthIran.ThelocationsofmajorstructuralzonesconsistingofSanandaj-SirjanZone,

CentralIranianBlock,MainZagrosThrustandZagrosFoldedBeltareindicated.

REFERENCESAgard,P.,Monie,P.,Gerber,W.,Omrani,J.,Molinaro,M.,Meyer,B.,Labrousse,L.,Vrielynck,B.,Jolivet,L.&Yamato,P.,2006:

Transient, synobduction exhumation of Zagros blueschists inferred fromP-T, deformation, time, and kinematicconstraints:ImplicationsforNeotethyanwedgedynamics.JournalofGeophysicalResearch,111,B11401,1-28.

Ewart,A.,Collerson,K.D.,Regelous,M.,Wendt,J.I.&Niu,Y.,1998:GeochemicalevolutionwithintheTonga-Kermadec-Lauarc-backarcsystems:theroleofvaryingmantlewedgecompositioninspaceandtime.JournalofPetrology,39,331-368.

McCulloch,M.T.&Gamble, J.A.,1991:Geochemicalandgeodynamicalconstraintsonsubductionzonemagmatism.EarthandPlanetaryScienceLetters,102,358-375.

Pearce, J.A., 1980: Geochemical evidence for the genesis and eruptive setting of lavas from Tethyan ophiolites. In:Panayiotou, A., (Eds.), Ophiolites. Procceding International Ophiolite Symposium, Nicosia, Geological SurveyDepartment,261-272.

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Transtensional basin system in Central Iranian Volcanic Belt

R.Monsef*,M.H.Emami**,N.RashidnejadOmran***

*ISLAMICAZADUNIVERSITY,ESTAHBANBRANCH,IRAN(zaos13000@yahoo.com)**RESEARCH INSTITUE FOR EARTH SCIENCES, GEOLOGICAL SURVEY OF IRAN.*** GEOLOGY DEPARTMANT BASIC SCIENCE FACULTY, TARBIAT MODARES UNIVERSITY,PO. 14115-111,TEHRAN

Urumieh-Dokhtarmagmaticzone(UDMZ)hasbeenconsideredasaplaceforthemainmagmaticactivitiesintheCentralIraniancontinentintheCenozoic(mainlyineocene).MagmatismisspatiallyandtemporallyassociatedwithAlpine-Himalayacollisionaltectonics.ExplosiveactivitiesinPaleogeneandearlyNeogenewerecommonlyfromfissureeruptionsandfeederdikeshadadomonantroleforcreationofthicksequencesofmagmaticandpyroclasticrocks.TheSlafchegantoDelijanre-gioncoversanareaabout500sq.Itischaracterizedbyanumberofsubparallelmountainsanddepressions,runningNW-SEbelongstoNeogene.centeralventeruptionscausedforcreationofstrata-volcanoesinthestudyareaandvarientofvolcanicdomes incontinentalenvironment.TheNeogenevolcanicactivitiesaredividedintotwophases:Atthefirststage (Ngv

1),

volcanicrockscontainbasalttoandesite-basaltaslavaorpyroclasticmaterials.Theexplosiveeventwasfollowedbythevolca-nictosubvolcanicassociationsofNgv

2withproductsofmainlyandesitictorhyioliticcomposition.Thevolcanicdomesof

Ngv2 and their diverse modes of emplacement are especially characteristic of this phase as Kuh-e-Aleh (fig.1).

Petrography,GeochemistryandmineralchemistrydataconfirmthepresenceoftranstensionalregionsalongtheUrumieh-Dokhtarmagmaticzone(UDMZ),openedduringPaleogeneandearlyNeogeneduetothecollisionoftheArabiaplatformandCentralIraniancontinent.AtTertiarytime,thetimespanbetweentheLaramidianandMio-Pliocenephaseisrelatedtotheopeningupofthebasins(intercontinentalrift),theextensionalphenomenonmovingslowlyattheendoftheEoceneandthebeginningoftheOligocene.LocalNogenevolcanismduetotranstensionalregionshappensinOligo-Miocene.Theclo-singofthebasins,orcompressionalperiod,beganwiththeMio-Pliocenemovementwhichcausedthefoldinganduplif-ting.

Figure1.GeologicalourviewmapofNeogenevolcanicactivities.1:25000

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y REFERENCESEmami.M.H., 1981,Geologie de la region deQom-Aran (Iran) contribution a l etude dynamique et geochimique du

volcanismetertiairedelIranCentral,TheseDoctoratEtatGrenoble,489Ricou, L.E., 1994. Tethys reconstructedplates, continental fragments and their boundaries since 260Ma fromCentral

AmericatoSouth–easternAsia.GeodynamicaActa(Paris)7.Verdel,Charles,2009,CenozoicGeologyofIran:Anintegretadstudyofextensionaltectonicsandrelatedvolcanism,Thesis

doctorofphilosophy,CaliforniaInstituteforTechnology.

3.28

Metamorphic evolution of a kyanite-eclogite from Thermes, Rhodope Massif, Greece.

MoulasEvangelos*,KostopoulosDimitrios**

*GeologischesInstitut,ETHZürich,Sonnegstrasse5,8092Zurich,Switzerland(moulase@student.ethz.ch)**Department of Mineralogy and Petrology, Faculty of Geology and Geoenvironment, School of Sciences, National and Kapodistrian University of Athens, 157 84 Athens, Greece

TheRhodopeMassifinnorthernGreeceisarecentlyidentifiedultrahigh-pressuremetamorphic(UHPM)provincecompri-sing garnetiferous metapelites and eclogites with microdiamond inclusions. These rocks preserve evidence of melting(T>1100°C;P>7GPa) ina Jurassic subductionzoneanda complex reheatinghistoryat thebaseof the crust in theearlyTertiary.

Akyanite-eclogitefromtheThermesarearevealsthepressure-temperature-timepathfollowedbytheRhodopeUHPMrocks.Texturesinvolvingphengiticmicaindicatemeltingathighconfiningpressures.Quartzinclusionsinkyaniteshowmulti-polygonaldomainsandradialcrackssuggestingformercoesite,hencePconditions>2.7GPa(atabout700°C).

ClinopyroxeneformedunderUHPconditionswasreplacedbydiopside+plagioclasesymplectiteswhereaskyanitewasre-placedbycorundum+plagioclasesymplectitesduringdecompression.Thelatterreactionoccurredinlocallysilicaundersa-turated domains of the rock (Godard&Mabit 1998). Large porphyroblastic amphiboleswith taramitic coresmantled bypargasiticcompositionsattestamphiboleformationviahydrationreactionsintheeclogite-faciesandlaterdecompressiontotheamphibolitesfacies.

Subsequentgranulitisationproceededviareactionsbetweeni)garnetporphyroblastsandmatrixdiopsidetoformcoronasofplagioclase+ilmenite+magnetite+sodicgedritearoundgarnet,ii)corundumanddiopsidetoformspinel+plagioclasesymplectitesafterkyaniteandiii)kyanite,spinelandcorundumtoformsapphirine(Liati&Seidel1996).Theseimplythatconditionsofapproximately1.5GPaatT>800°Cwereattained,possiblyassociatedwithasecond-stagepartialmeltingepiso-de.ZircongeochronologyusingSHRIMPrevealedamiddleEoceneage(~42Ma)forgranuliteformation.Thisage,inconjunc-tionwiththecoevalageofapophysesoftheSkalotigraniteinthearea,isconsistentwiththegeneralhistoryoftheRhodopeMassifundergoinggeneralexhumationandcrustalcollapseinEocenetimes.

REFERENCESGodard,G.&Mabit,J.-L.1998:Peraluminussapphirineformedduringretrogressionofakyanite-bearingeclogitefromPays

deLéon,ArmoricanMassif,France,Lithos43,15-29.Liati,A.& Seidel, E. 1996:Metamorphic evolutionandgeochemistryofkyanite eclogites in centralRhodope,northern

Greece,Contrib.Mineral.Petrol.123,293-307.

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Rheological properties of crystal- and bubble-bearing silicic magmas: pre-liminary experimental results

PistoneMattia*,CaricchiLuca**,BurliniLuigi***,UlmerPeter*

* ETH-Institute for Mineralogy and Petrology, Clausiusstrasse 25, CH-8092 Zurich, Switzerland (mattia.pistone@erdw.ethz.ch; peter.ulmer@erdw.ethz.ch)** University of Bristol, Wills Memorial Building - Queen's Road, BS8 1RJ Bristol (ca.luca@live.com)*** ETH-Geological Institute, Sonneggstrasse 5, CH-8092 Zurich, Switzerland (luigi.burlini@erdw.ethz.ch)

Naturalmagmasaremixturesofsilicatemelts,crystalsandgasbubbles.Theviscosityofsuchmulti-phasemixturesisthesinglemostimportantpropertycontrollingtheeruptivebehaviorofvolcanoes.Therheologicalbehaviorandthephysicalpropertiesofmagmasdependprimarilyon theviscosityof thesilicatemeltandontherelativecontentsofcrystalsandbubbles(Caricchietal.2007;Llewellin&Manga2005)aswellasontheinteractionsbetweenthesethreephases.Theshapeandsizedistributionofcrystalshasbeendemonstratedtoinfluencesignificantlythevariationofviscositywithrespecttothecrystalfraction.Inaddition,thenon-Newtonianbehaviorofmagmas(viscositydecreaseswithincreasingde-formationrate)hasbeenassociatedtothegeometricalorderingofsuspendedparticlesinthemagma(Caricchietal.2007;Costaetal.2009).

Bubblesexertcontrastingeffectsontherheologicalbehaviorofmagmasdependingonappliedstressconditions.Deformingbubblescausetheviscositytodecreasewhilesphericalgasvesiclesbehaveascrystals,thusincreasingthemagmaviscosity.Wepresentnovelexperimentalresultsontherheologicalbehaviorofmagmascomposedofliquidandboth,gas-pressurizedbubblesandcrystals,deformedatmagmaticpressuresandtemperatures.Thisstudyaimstoconstrainthedependenceofrheologicalandphysicalpropertiesofmagmasontheviscosityofthesilicatemelt,ontherelativecontentsofcrystalsandbubblesandontheinteractionsbetweenthesethreephases.ThestartingmaterialconstitutesofahaplograniticmeltcontainingvariableamountsofH

2O(2.68wt%and5.25wt%)and

CO2(2.06wt%and4.97wt%)anddifferentproportionsofquartzcrystals(between24and65vol%;63-125µmindiameter)

andbubbles(between7and22vol%;5-150µmindiameter).TheexperimentswereperformedinsimpleshearusingaHT-HPinternally-heatedPaterson-typerockdeformationapparatus(Paterson&Olgaard,2000)atstrainratesrangingbetween5·10-5s-1and1·10-3s-1,atapressureof200MPaandtemperaturesbetween773and923K.

AtthesetemperatureandstrainrateconditionsthesilicatemeltbehavesasaNewtonianliquid(Webb&Dingwell,1990).Consequently,non-Newtonianeffectscanentirelyberelatedtothepresenceofbubblesandcrystals.Inallexperimentalrunsamarkedweakeningbehavior(decreaseofstresswithincreasingstrain)wasobserved.Back-scatteredelectronimageswereacquiredonexternalportionsofthesamples,wherethesimpleshearconfigurationisbestappreciated.These imagesclearlyhighlight thepresenceofmelt-enrichedportionsof thesampleswerebubblesarestronglydeformed.Incontrast,inregionssurroundingthesemelt-enrichedbands,bubblesarealmostsphericaltestifyingthattheseportionsofthematerialsufferedasignificantlyloweramountofdeformation.Locally,deformedbubblesbetweencrystalsresultingfromlocalstressconcentrationgeneratedbythesolidparticlescanbeobserved.Themeasuredweakeningismostprobably related to thegenerationofmelt-enriched shearbands.The localizationofdeformation in these lowerviscosityregionsresultsinadecreaseofviscositywithincreasingstrain(shearthinningeffects).

Thesepreliminaryexperimentalresultsservetoguideourongoingexperimentaleffortstofinallyobtainrheologicallawsfor crystal and bubble bearingmagmas to simulate andpredict volcanic eruptions from shallowmagma reservoirs andvolcanicconduits.

REFERENCESCaricchi,L.,Burlini,L.,Ulmer,P.,Gerya,T.,Vassalli,M.&Papale,P.2007:Non-Newtonianrheologyofcrystal-bearingmagmas

andimplicationsformagmaascentdynamics.EarthPlanet.Sci.Lett.264,402-419.Costa,A.,Caricchi, L.&Bagdassarov,N.S. 2009:Amodel for the rheologyofparticle-bearing suspensions andpartially

moltenrocks.Geochem.Geophys.Geosyst.10,1-13.Llewellin,E.W.&Manga,A.2005:Bubblesuspensionrheologyandimplicationsforconduitflow.J.Volcanol.Geotherm.Res.

143,205–217.Paterson,M.S.&Olgaard,D.L.2000:Rockdeformationteststolargeshearstrainsintorsion.J.Struct.Geol.22,1341-1358.Webb,S.L.&DingwellD.B.1990:Non-Newtonianrheologyofigneousmeltsathighstressesandstrainrates:experimental

resultsforrhyolite,andesite,basaltandnephelinite.J.Geophys.Res.95(B10),15695-15701.

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Complexities in the high pressure metamorphic history of the central Sesia Zone near Cima di Bonze (NW Italy)

DanieleRegis*,PaolaManzotti*,KatherineBoston**,BenedicteCenki-Tok*,MartinRobyr*,DanielaRubatto**,TonnyThomsen*,MartinEngi*

*University of Bern, Baltzerstrasse 3, CH-3012 Bern, Switzerland (regis@geo.unibe.ch)**The Australian National University, Mills road, Canberra, ACT, 0200 Australia

ThecentralSesia-LanzoZoneincludesanarrow,continuouslysurfacingunit,whichwastermedMonometamorphicCoverComplex(MCC)byVenturini(1995).TheMCCcomprises:(a)theBonze Unit,composedofbasicrocks(metagabbrosandglau-cophane-eclogites), found in tectonic contact with (b)metasediments (calcschists, metamarls, impure quartzites) of theScalaro Unit.ThecontactsbetweenthisbodyandthetwolargebasementblocksoftheSesiaZoneareclearlytectonicandmostlypredatetheeclogiticmetamorphism.

Rubattoetal.(1999)showedthatgabbrosoftheBonzeUnithadintrudedthecrystallinebasementintheearlyCarboniferous.Blasto-myloniticmetagabbroscontainlocalrelicsofbrownhornblende;thesemayreflectpre-Alpinemetamorphism(amphi-bolitefacies?).However,norelicsofapre-AlpinestagehavebeenfoundinthemetasedimentsoftheScalaroUnit.ThisunitisthusagoodtargetforstructurallycontrolledpetrochronologyoftheAlpineevolutioninthecentralSesiaZone.

Wereportresultsofdetailedstructural,petrographic,chemicalandgeochronologicalworkcarriedoutintheCimaBonzeregion,withafocusonimpurequartzitesofthepoly-deformedScalaroUnit.ApervasiveHPplanarstructure(S2foliation)dominatesintheareastudiedandinthesamplesanalysed.SeveralgenerationsofmetamorphicallaniteandLREE-richepi-doteoccur,providingarobust(Th-Pb,U-Pb)chronometerthatcanbeintimatelylinkedtothepetrologicalandmicro-struc-turalevolution.ThreegrowthzoneswithvariableREEandU-Thcontentswererecognizedintheseallanites,andretrogres-sivetinyrimsofclinozoisite/epidotewereoftenobserved.PhaserelationsbetweenallaniteandotherREE-richphaseswerecarefullystudiedandyieldaveryclearandinterestingsequence.Epidoteoftenincludesrelicsofmonazite,thorite,apatiteandxenotime.Thephaserelations indicate thereaction:monazite+ fluidàallanite+ thorite+apatite.LargecrystalsofxenotimeformingcoronasonzirconareassociatedwithsmallcrystalsofthoriteandREE-poorallanite.

SHRIMPU-Th-Pbin situdatingofthethreegrowthzonesconsistentlyyieldthreedifferentAlpineages(from83Mato65Ma).PreliminaryLA-ICP-MSdataonthesamesamplesconfirmtheionproberesults.Furtherelectronmicroprobedatingisun-derwayonmonaziteandthoritetounderstandtheirrelationstoallaniteandtounravelwhethertheearlymonaziteisaprogradeoradetritalphase.

TheseresultshaveimportantimplicationsontheAlpineHP-evolutionoftheSesiaZoneasawhole.AdetailedPTDt-pathispresentlybeingbeworkedout,butthepreliminarydatainanycaseindicateacomplex,protractedreactionsequencepro-ducingallaniteoverat least10m.y.Thismayserve toexplainat least someof thecomplexAr-Aragepatterns foundbyVenturini(1995).

REFERENCESRubattoD.,GebauerD.,CompagnoniR. 1999:Datingof eclogite-facies zircons: theageofAlpinemetamorphism in the

Sesia-LanzoZone(WesternAlps).EarthPlanet.Sci.Letters167,141-158.VenturiniG. 1995:Geology, geochemistry and geochronology of the inner central Sesia Zone (WesternAlps – Italy).

MémoiresdeGéologie,Lausanne,25,148pp.

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try3.31

The temporal evolution of the Mitu group, south-east Peru – first U-Pb age data.

ReitsmaMariël*,SchalteggerUrs*,SpikingsRichard*,CarlottoVictor**

*Earth and Environmental Sciences, Rue des Maraîchers 13, CH-1205 Genève**INGEMMET, Av. Canada 1470 San Borja, Lima, Peru

TheEasternCordilleraofsouthernPeruformedalongacrustalzonethathasbeenactiveaspartofthewesternGondwanamarginsincethemiddlePaleozoic.ThepresentstudyinvestigatestheMituGroupofsouth-eastPeruintheareaofAbancay-Cusco-Sicuani-Titicaca. This unit comprises continental clastic sediments deposited in syn-sedimentary basins during anextensionalperiodinPermo-Triassictimesandhasnotbenefittedfromathoroughgeochemical-geochronologicalinvestiga-tionsofar.Oneofthemainreasonsforthislackofdataisacomplexstructureofthegrabensystem,tectonicallycomplicatedbycompressionalinversionoftheextensionalbasinsduringAndeanorogeny.Duetodominatingcoarse-grainedclastics,theMituGroupisdevoidoffossilsanditsageisonlypoorlybracketedtobePermo-TriassicbasedonitsstratigraphicrelationtotheunderlyingCopacabanaandoverlyingPucaragroups.TheupperlevelsoftheCopacabanahavebeenconstrainedbypa-lynologytotheArtinskian(DoubingerandMarocco,1981).However,ahiatusmaybeobservedbetweentheCopacabanaandtheMitugroupsinmostplaces,renderingtheageestimateofthebasalMituimprecise.ThePucaraGroup,regardedbyRosasetal.(2007)asthermalsagafterMituextension,isattributedtothelateTriassic-earlyJurassiconthebasisofammonitefossilsandU-Pbzirconagesfromashbeds(Schalteggeretal.,2008).TheaimofthisstudyistoprovidemoreaccurateandpreciseageconstraintsfortheageanddurationoftheMituGroupbyusingU-Pbgeochronologyofvolcaniczirconinrhyo-liticlavas,andofdetritalzirconinclasticsediments.Forandesiticvolcaniclithologies,ageapproximationswillbeobtainedbyAr-Artechniquesappliedtoamphiboleandgroundmasssamples.

FielddatawereobtainedfromalongandapparentlycompletesectionthroughtheMitu,situated120kmSEofCusconearthecityofSicuani.ThissectionconsistsoftypicalMitudeposits;continentalredbeds,brecciasandandesiticlavas.However,azircon-bearingrhyoliticlavaatthebottomgivesustheopportunitytodatethestartofMitusedimentationbyU-PbID-TIMS;thisanalysiswillprovideapreciseageforthebaseoftheMitugroupforthefirsttime.IntheSicuaniareatheMituuncon-formablyoverlies theAmbogroup, suggesting that theentireCopacabana ismissing. Laser-ablation ICP-MSU-PbdataofdetrialzirconsfromasandstonejustbelowtheunconformityindicateamaximumageoflatestCarboniferous(303Ma)fortheunderlyingAmbogroup.ThismaximumageoverlapswiththepalynologicalageofthelowerCopacabana(Azcuyetal.,2002),raisingthequestionwhethertheAmboandCopacabanaaretrulydiachronousorjustcoevalunitsofdifferentsedi-mentaryfaciesassociations.Inanothersection,100kmWofCusco,nearthecityofAbancay,wefoundMitusedimentsoverlyingtheCopacabanaGroup.HeretheCopacabanacontainswellpreservedplantfossilsofthelycopsidsfamilyalsofoundelsewhereinPeruandBolivia.LackofacidicvolcanismduringMituextensioninthisregionprevents fromdatingof lavasusingtheU-Pbmethod.Thedetritalzirconpopulationinasandstone inthe lowermostpartof theMituwasanalysedforU-Pbages,usingLA-ICP-MStechniques.Theyoungestzirconsinthepopulationarearound235MahenceprovidingamaximumagefortheonsetofMitugroupsedimentation.TheArtinskianagefortheupperCopacabanafromDoubingerandMarocco(1981)hasalsobeenob-tainedfromtheAbancayregion,establishingahiatusofsome50Myrsbetweenthetwounits.TheMituGroupisintrudedbya220Magranitebody(LipaandSaraiva,2008)indicatingsignificantburialofthesedimentsatthistime.500kmSEofCusco,ontheBolivianshoresoflakeTiticaca,theAmboGroupfeaturesplantfossilsoftheLycopsidsfamilylikethosefoundintheCopacabananearAbancay.OurdetritalzirconLA-ICPMSstudyonaquartzarenitejustbelowthefossilsindicatesamaximumU-Pbageof343Ma.Howeverazircon-bearingashbedwillallowformoreprecisecalibrationofthefossilagebyID-TIMStechniques.ThezirconU-PbdatawillprovideatestwhethertheCopacabanaandtheAmbogroupareindeeddiachronousorjustlateralvariationsofasedimentarysystem.

REFERENCESAzcuy,C.L.,DiPasquo,M.&ValdiviaAmpuero,H.2002:LateCarboniferousmiosporesfromtheTarmaFormation,Pongode

Mainique,Peru.Reviewofpalaeobotanyandpalynology118,1-28.Doubinger, J., andMarocco,R. 1981:ContenuPalynologiqueduGroupeCopacabana (Permien Inférieur etMoyen) sur la

bordureSuddelaCordillèredeVilcabamba,régiondeCuzco(Pérou).InternationalJournalofEarthSciences70,1086-1099.LipaSalas,V.&SaraivaDosSantos,T. 2008:Geocronologiayevolucion tectonicadelplutonAbancay-Apurimac-Peru.XIII

Latin-Americangeologicalcongress:Lima,Peru.Rosas,S.,Fontboté,L.&Tankard,A.2007:TectonicevolutionandpaleogeographyoftheMesozoicPucaraBasin,centralPeru.

JournalofSouthAmericanEarthSciences24,1-24.Schaltegger,U.,Guex,J.,Bartolini,A.,Schoene,B.&Ovtcharova,M.2008:PreciseU-Pbageconstraintsforend-Triassicmass

extinction,itscorrelationtovolcanismandHettangianpost-extensionrecovery.EarthandPlanetaryscienceletters267,266-275.

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Single-crystal elastic properties of superhydrous phase B determined by Brillouin scattering spectroscopy

RosaAngelikaD.*,Sanchez-ValleCarmen*,WangJingyun*&SaikiaAshima*

*Institute for Mineralogy and Petrology, ETH Zurich, Zurich 8092, Switzerland (angelika.rosa@erdw.ethz.ch)

SuperhydrousphaseB,Mg10Si

3O

18H

4,(herereferredtoasShyB)belongstothegroupofDHMSphases(densehydrousmagne-

siumsilicates),thatarelikelythemostimportantwaterreservoirsindeepsubductedslabs.Inordertoformulateaccuratemineralogicalandcompositionalmodelsofsubductedslabsandtointerpretseismicobserva-tioninthisarea,preciselymeasuredelasticitydataatrelevantP-Tconditionsareneededbutarenotoftenavailable.

InthiscontributionwepresentresultsofBrillouinscatteringmeasurementsofthesoundvelocitiesandsingle-crystalelasticpropertiesofShyBatambientconditions.Brillouinscatteringisoneofthemostpowerfulandprecisemethodtoinvestigatetheelasticpropertiesof single-crystalsandpolycrystallinesamplesof small size.TheShyBsingle-crystalsusedhereweresynthesisedinaWalkermodulemultianvilpressof1000tonatIMP,Zurichat20GPaand12000C.TheVoigt-Reuss-Hillaver-agefortheadiabaticbulkandshearmoduliareKs=150(3)GPaandµ=98(2)GPa,respectively.ThepresentresultsareingoodagreementwithapreviousBrillouinscatteringstudybyPacalo&Weidner(1996)[1].Thebulkmodulusobtainedinthisstudyisalsoingoodagreementwiththeresultsofaprevioussingle-crystalPVstudy[2]butresolvediscrepanciesbetweenpreviouscompressionalstudiesusingpowderedsamples[3,4].Theresultsshowthattheaggregatecompressionalandshearwaveve-locitiesofShyB(V

P=9.17(9)and V

S=5.43(4) km/s)arethelowestamongcoexistingphasesinsubductedperidoties,including

Mg-Perovskite,hydrousRingwooditeorFerropericlase.Thevelocitydistributioncalculatedfromthebest-fitelasticmodelofShyBrevealsanearlyisotropicseismicbehaviourofShyBatroomconditions.Thecompressionalanisotropy(A

P)isonly6.6%

whileslightlyhighershearanisotropy(AS)of11.6%isobserved.IfthemoderatedanisotropyofShyBismaintainedathigh

P-T,thestrongseismicanisotropyobservedinsubductedslabsbelowthetransitionzone,maynotberelatedtothepresenceofShyB.

REFERENCES[1]Pacalo,R.E.G.andWeidner,D.J.1996:ElasticityofsuperhydrousB.PhysicsandChemistryofMinerals,23,520-525.[2]Kudoh,Y.,Nagase, T.,Ohta, S., Sasaki, S., Kanzaki,M., andTanaka,M. 1994:Crystal structureand compressibilityof

superhydrousphaseB,Mg20Si6H8O36.InS.C.Schmidt,J.W.Shaner,G.A.Samara,andM.Ross,Eds.High-PressureScienceandTechnology,Am.Inst.Phys.Conf.Proc.,309,p.469-472.

[3]Inoue,T.,Higo,Y.,Yamada,A.,Irifune,T.&Funakoshi,K.2006:High-pressureandhigh-temperaturestabilityandequationofstateofsuperhydrousphaseBbyinsituX-raydiffraction.InS.D.Jacobsen,andS.VanderLee,Eds.EarthDeepWaterCycle,p.147-157.AGU,WashingtonDC.

[4] Litasov, K.D.,Ohtani, E.,Ghosh, S.,Nishihara, Y., Suzuki, A. and Funakoshi, K. 2007: Thermal equation of state ofsuperhydrousphaseBto27GPaand1373K.PhysicsoftheEarthandPlanetaryInteriors,164,142-160.

3.33

The influence of volatiles in basaltic explosive eruptions: the example of the Chaimilla eruption (3.1 Ka, Villarrica Volcano, Chile).

ScalisiRosalinda1,CostantiniLicia1,BonadonnaCostanza1,DiMuroAndrea2

1Section des sciences de la Terre et de l’environnement 13, Rue des Maraichers, Ch-1025 Genève(s.linda84@tiscali.it) 2Laboratoire de physique et chimie des systèmes volcaniques, IPGP-Paris VI, Paris, France

Villarricaisabasaltic-andesitestratovolcanolocatedintheSouthernChileanAndes.ItisoneofthemostactivevolcanoesinSouthAmericaassociatedwitheast-dippingsubductionoftheNazcaplatebeneaththeSouthAmericanplate.Althoughitshistoricaleruptiveactivityhasbeenmainlyeffusive,initshistoryVillarricavolcanohadalsoexplosivebehaviorproducingbothlargepyroclasticdensitycurrentsandtephrafallout.Thelargest-volumeeruptionsaretheLìcanIgnimbrite(~10Km3,~14,000BP)andPùconIgnimbrite(~5Km3,~3500BP)(Witteretal.,2004), bothofbasaltic-andesitecomposition.Themostre-

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trycentpyroclasticdensitycurrentoccurred~1620BP(Morenoetal.,1994). Afterthelasteruption(1984-1985),Villarricavolca-

nohashadacontinuouspassivedegassingactivityfromthesummitlavalake(Witteretal.,2004). InthisprojectwehaveinvestigatedtheinitialconditionofVillarricamagmastoragereservoirandtheroleofdifferentvola-tilespeciesincontrollingtheeruptiondynamicsofChaimilladeposit(~3,100BP),whichisthebestpreservedandmostwi-delydispersedtephrafalloutofVillarricavolcano.Thisisdonebyadetailedpetrographicalandgeochemicalstudyofolivine-hostedmeltinclusionsandofallthephasespresentinthesystem(i.e.mineralsandglassmatrix).

ThepetrographicalandgeochemicalstudyhasbeencarriedoutattheUniversityofGenevaandLausanne(forEMPanalysis)withtheexceptionofH

2OandCO

2analysesofmeltinclusionswhichwasdoneattheLaboratoryPierreSùe(Paris,France)

usingbothFTIRandRAMANtechniques.

Ourpreliminaryresultsshowthatthemagmachemistrydidnotchangeduringtheevolutionoftheeruption(SiO2content

ofwholerockis~53wt%andSiO2contentofmeltinclusionvariesbetween52and56wt%)withexceptionoftheuppermost

falloutlayers,whichshowaslightlymoreprimitivecomposition(SiO2contentofwholerockis~52wt%andSiO

2contentof

meltinclusionis~51wt%).Pre-eruptiveH2Ocontentisrelativelyhigh(~2-3wt%)forabasalticmagma,butthishighcontent

has been frequently found in other high-explosive basaltic eruptions (e.g. Metrich et al.,2004; Spilliaert et al., 2006;Roggensacketal.,1997).InadditionChaimillameltinclusionsdonotcontainCO

2suggestingarelativelyshallowmagma

reservoir.

A B

FigA:meltinclusionpresentinolivine(SamplesfromChaimillascorias,Villarricavolcano,Chile).FigB:differentolivinecrystalsofChaimilladeposit.

REFERENCESMétrichN,AllardA,SpilliaertA,AndronicoD,BurtonM(2004).2001flankeruptionofthealkali--andvolatile-richprimitive

basaltresponsibleforMountEtna.EarthandPlanetaryScienceLetters,228,1-17.MorenoH,ClaveroJ,LaraL.(1994).Actividadexplosivapost-glacialdelvolcanoVillarrica,AndesdelSur.Septimocongreso

geologicochileno.Universidaddeconcepcion.Conception,Chile,329-333.RoggensackK,Hervig RL,McKnight SB,Williams SN (1997). Explosive basaltic volcanism fromCerroNegro volcano:

Influenceofvolatilesoneruptivestyle.Science,277,1639-1642.SpilliaertN,Allard P,MetrichN, SobolevAV (2006).Melt inclusion record of the conditions of ascent, degassing and

extrusion of volatile-rich alkali basalt during the powerful 2002 flank eruption ofMount Etna (Italy). Journal ofGeophysicalResearch111:doi:10.1029/2005JB003934.

WitterJ.B,KressV.C,DelmelleP,StixJ(2004).Volatiledegassing,petrology,andmagmadynamicsoftheVillarricaLavaLake,SouthernChile.JournalofVolcanologyandGeothermalResearch,134,303-337.

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An experimental study in the system Fe-Mg-Ti-Cr-Si-O±Al: ilmenite solid solution as a function of pressure and temperature

SemytkivskaNina*,UlmerPeter*

*Department of Earth Science. ETH Zurich, Clausiusstr.25, 8092 Zurich

WiththeaimofimprovingtheexperimentalbasisofthecalibrationinthesystemMg-Fe-Ti-Cr-Al-Si-O,wedoneexperimentalstudywithparticularattentiontopicro-ilmenite.Experimentswereperformedattemperatureof1000-1400

o

Candpressureof2.5,3.5,and5GPausingdifferentbulkcomposi-tionswithvariableMg/Fe,Cr/Alratios,andsilicaactivityunderrelativelyreducingconditionsbyemployinggraphitecon-tainerssealedintoPt-capsule.Experimentswereruninsolid-mediapistoncylindersandmulti-anvilapparatusfordurationsof30-120hours.Differentphaseparagenesiswasobservedatourexperimentalproducts.Bulkcompositionhasamarkedeffectonthephaseparagenesis,inparticular,stabilityofthephasesisinfluencedbytheMg#ofthesystem.Ilmeniteisstabletogetherwitholivine+orthopyroxene+spinelatbulkXMgof0.73(tab.1,2).rutile+olivine+opx+spinelarecoexistingphasesatabulkX

Mgof0.85.CompositionwithlowerSiO2contentsandlowXMgvaluesarecharacterizedbythepresenceofthreeoxides:

ilmenite+rutile+spinelcoexistingwitholivineandopx.CompositionswithhighXMg(0.85)andlowerSiO

2contentsresult

inthedisappearanceofopxandrutile;presentphasesareolivine+spinel+ilmenite.

TheexperimentaldatasetwasusedtodetermineequilibriumfractionationofFeandMgbetweencoexistingolandilm,andappliedtoformulatemodelforilmenitesolidsolutionandintendedtoprovideanewversionofilmenite-olivineanexchangegeothermometerthatcouldbeapplicabletotheCr-richassemblage.

3.35

Pyroxenite veins in the Jurassic Pindos Ophiolite (NW Greece): cm-scale mantle heterogeneity preserved in MORB-source peridotites

DmitryS.Sergeev*,**,ArjanH.Dijkstra*

*Université de Neuchâtel, Institut de Géologie et d’Hydrogéologie, Switzerland (dmitry.sergeev@unine.ch)**Université de Lausanne, Institut de Minéralogie et Géochimie, Switzerland

Geochemicaland isotopicdifferencesbetweendifferent typesofMORBarecommonlyattributed toheterogeneity in themantlesource.Oneofthemajorfactorsthatcancausesuchheterogeneityisthepresenceofrecycledoceancrust.Webelie-ve that traces of suchheterogeneities can be preserved in pyroxenite veins in ophiolitic peridotite bodies. TheDramalaComplexinthePindosophiolite(NWGreece)isaperidotitebodywithamid-oceanridgecharacter,wherewefoundakm-sizedstructuraldomainwithcoarse-grainedmantletectonitesand1-10cmthickpyroxeniteveins.Pyroxenitesareconcor-danttothehightemperaturedeformationstructuresinthehostperidotitesandshowmetamorphic,replacivetexturesinthinsections.

WemeasuredHighlySiderophileElements(HSE,i.e.,Os,Ir,Ru,Pt,Pd,Re)andOsisotoperatiosinwholerockpyroxenitesandwall-rockperidotites.Pyroxeniteswerecarefullycut fromtheenclosingperidotites.HSEpatterns inbothcaseshaveidenticalcharacter; somesmalldifferences in incompatibleHSEconcentrations (Pt,Pd,Re)occurdue to thepresenceofsulphidesinpyroxenites.Peridotiteshavechondritictosubchondritic187Os/188Osratios(0.1196-0.1291),whereasthepyroxe-nitesareallsignificantlymoreradiogenic(187Os/188Os=0.1418-0.1980).Thesedifferencecannotsimplybeexplainedbydiffe-rencesinRe/Osratiosbetweenperidotitesandpyroxenites.Geochemicalandpetrographicdatashowthatconcordantpyro-xenitesrepresentsrelicsofreplacivepyroxenitesformedmelt-rockreactionbetweenpyroxene-saturatedmeltsandperido-tite.

Thefactthatpyroxenitelayersareparalleltothefoliationinhigh-temperaturedeformedperidotitetellsusabouttheirear-ly-stageorigin.BasedontexturesandHSEconcentrations,weproposethatpyroxenitesexposednowarereplaciveproducts

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tryofSiO

2-richmelts,derivedfromthemeltingofoldmaficlayerswithintheperidotites,withveryradiogenic187Os/188Osisoto-

peratios,sincenoothersourceofhigh187Os/188Osisotoperatioislikelytoexistintheserocks.Moreoverwesuggestthatthemeltdidnotgenerallymigrateoverlargedistancesperpendiculartothepyroxenites,i.e.,thatthepyroxenitesareessential-lythewall-rockoftheoldmaficlayers.Ifourinterpretationiscorrect,thenthesearethefirsttracesofisotopicmantlehe-terogeneityinresidualMORB-sourcemantleobservedsofar.ThepresenceofpyroxeniteswithsuperchondriticOsisotoperatiosinthemantlecanexplainwhyestimatesfor187Os/188Osisotoperatiosofdepletedmantlerocksaregenerallysubchon-dritic.

3.36

The Zagros Collision Zone: Petrological and geodynamical constraints on Inner and Outer Zagros Ophiolitic Belt

HadiShafaiiMoghadam*,RobertJ.Stern**,MohamadRahgoshay***

*School of Earth Sciences, Damghan University of Basic Sciences, Damghan, Iran, E-mail: hshafaii@dubs.ac.ir** Geosciences Department, University of Texas at Dallas, Richardson, TX 75083-0688, USA***Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran

DespitebroadaffinitiestootherophiolitesintheTethyanMediterranean-Omanophiolitebelt,theupperCretaceousophio-litesofSWIranremainrelativelyunknownintermsofgeochemistry,petrogenesisandtectono-magmaticevolution.Zagrosophiolitescomprisetwoparallelbelts, includingInnerZagrosOphioliticBelt (IB),alongtheSWperipheryoftheCentralIranianblockandOuterZagrosOphioliticBelt(OB),southofMainZagrosThrustFault.IBandOBophiolitesformedatthesametime:IBhornblendegabbrosyieldaK/Arageof93MawhereasOBdiabasesandhornblendegabbrosyieldAr/Aragesof86-93Ma,similartoagesofotherophiolitesoftheMediterranean-Omanbelt(Oman~95Ma,Cyprus~90-94Ma).PelagiclimestonesrestingconformablyonIBandOBophiolitesareTuronian-Maastrichtian(93.5-65.5Ma).SeverallinesofevidencesuchashighCrcontentofharzburgitespinelandflatREEpatternsofthelavaswithnegativeNb-TaanomaliesfrombothinnerandouterbeltZagrosophiolites indicate formationaboveasubductionzone,alsosimilar tootherTethyanOman-Mediterraneanophiolites.These similarities inophioliteagesand tectonic setting suggest that theOman-Mediterraneanophiolitebeltrepresentsaremarkablycoherentlithosphericblock.TheparallelalignmentofZagrosophiolitesbetweentheUrumieh-DokhtararcandtheZagrosfold-and-thrustbelt (accretionaryprism),furthersuggeststhatIBandOBophiolitesmaybeexposedlimbsofadeformedanticlinoria,andrepresentfore-arcbasement.Inthisinterpretation,IBandOBrepre-sentinnerandouterportionsoftheLateCretaceousIranianfore-arc,developedoveranincipientN-dippingsubductionzoneonthesouthernEurasianmargin.TheZagrosfold-and-thrustbestisanaccretionaryprismthatformedbyoff-scrapingofArabianPlatesediments,andtheUrumieh-DokhtararcisanAndean-typearcthatiswaningastheregiontransitionsfromsubductiontocollision.

3.37

The transition from cold-wet to hotter-drier rhyolites in subduction zones: the case of the Kos-Nisyros-Yali volcanic center, Aegean arc, Greece

SkopelitisAlexandra*,BachmannOlivier**

*Earth and environmental science, Rue des Maraîchers 13, CH-1205 Genève, (Alexandra.Nowak@unige.ch)**University of Washington, Earth and Space Sciences Seattle, WA 98195-1310 (bachmano.@u.washington.edu)

Thecomplexityofmagmaticchambermechanismsareextensivelystudiedbutnotcompletelyunderstood.Severalparame-ters,suchastemperature,pressure,meltcompositionandcristallinity,canmodifyrheology,geochemistry,andgeometryofthechamberandthereforehaveanimportantinfluenceonthetypeandstyleoferuption.Magmaviscosityisstronglylinkedwithwatercontent,crystalcontentandtemperature.

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Twokindsofrhyoliteshavebeendefinedintheliterature(Christiansen2005):thefirstkindiscold(<750°C)andoxidized(NNO+1)whereasthesecondkindishotter(≥850°C)andmorereduced(~NNOorlower).Althoughbothareatornearvolatilesaturationinshallowcrustalmagmachambers,thecold-oxidizedtypeisobviouslymorewater-rich,asitcontainsbiotiteandlackspyroxene.Thewettypeisusuallyfoundinsubductionzonesettings,whereasthedriertypeismorecharacteristicofhotspotandextensionalenvironmentswheremantlemeltingoccursbyadiabaticdecompression.

ThepresentstudyshowsthatbothtypesofrhyolitescanbefoundinthesamelocalityintheAegeanArcinGreece(Fig.1).Wecomparedrhyoliticpumicesof theKosPlateauTuff (KPTeruptionage:160ky, (Smithetal.1996)) fromKos IslandtoNisyrosandYali,twosouthernmostislands.Therockschemistryshowsevolvedcompositionswithanaveragearound70%wtSiO

2forNisyrosand75-76%wtSiO

2forKPTandYali.

Thecaldera-formingKPTeruptedfromashallow(1.5-2.5kb)near-solidus(~670-700°C)andoxidized(NNO+1)magmacham-berthatwassaturatedwithawater-richgasphase.ThefollowingeruptionsfromNisyrosandYaliwereincontrast,100-150°C hotter, less oxidized (~NNO) andmainly contained plagioclase and clinopyroxene (although Yali does containminorquartzandsanidineaswell).Thereasonforthisshiftfromwettodrierrhyolitescanbeduetoeither(1)achangeinparentalbasaltcomposition(drierbasaltsleadingtodrierrhyolites)or(2)anefficientdegassingeventinducedbythecaldera-formingevent.Morestudies, includingexperimentworktoreconstructthetemperature-pressureconditionsbeforeeruptions,areneededtobetterunderstandwhichscenariocontributedtotheobservedshiftintheserhyolites.

Figure1.SimplifiedmapofKos,NisyrosandYali.(ModifiedafterAllen,2001)

REFERENCESAllen,S.R.2001:Reconstructionofamajorcaldera-formingeruptionfrompyroclasticdepositcharacteristics:KosPlateau

Tuff,easternAegeanSea.JournalofVolcanologyandGeothermalResearch105,141-162.Christiansen,E.-H.2005:Contrastingprocesses insilicicmagmachambers;evidence fromvery largevolumeignimbrites.

GeologicalMagazine142(6),669-981.Seymour,K.S.&Lalonde,A.1991:Monitoringoxygenfugacityconditionsinpre,syn-andpostcalderamagmachamberof

Nisyrosvolcano,Aegeanislandarc,Greece.JournalofVolcanologyandGeothermalResearch46,231-240.Smith,P.E.,York,D.,Chen,Y.&Evensen,N.M.1996:Singlecrystal40Ar/39ArdatingofaLateQuaternaryparoxysmonKos,

Greece:Concordanceofterrestrialandmarineages.GeophysicalResearchLetters23,3047-3050.Volentik,A.,Vanderkluysen, L., Principe,C.&Hunziker, J.C. 2005: StratigraphyofNisyros volcano (Greece). Thegeology,

geochemistryandevolutionofNisyrosVolcano (Greece). Implications for thevolcanichazards.MémoiresdeGéologie(Lausanne),26-66.

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try3.38

Dynamics of Cd, Pb and Cu cycling in a stream under contrasting photo-benthic biofilm activity and hydrological conditions

Tercier-WaeberMary-Lou*,**,HezardTeddy*&MassonMatthieu**

*CABE – Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, Sciences II, 30 Quai E.-Ansermet, CH-1211 Geneva 4 (Marie-Louise.Tercier@unige.ch)**Institut F.-A. Forel, University of Geneva, 10 Route de Suisse, CH-1290 Versoix

Thepastdecadestudiesperformedinriversandstreamsdemonstratedthatmanytracemetalandmetalloidexperiencedi-urnalcycles,withtotaldissolvedmetalconcentrationsoftenchangingone-tofive-foldduringa24hperiod.However,mostofthesestudieswereperformedinsummerunderlow-flowconditions.Moreover,sampleswerecollectedhourlybyhandforlaterlaboratoryanalysis.Thislaborioussamplecollectionandprocessingapproachlimitshourlysamplingto1–3daysatmaximum.Morefrequentanalysisisrequiredtounderstandtheseasonaloccurrenceandamplitudeofdielmetalcycles,andtheprocessescontrollingthesecycles.

Withthisgoalinmind,weappliedanautomatedvoltammetricanalyzertostudy,attimescaleofhourandundercontrast-ingbio-chemicalandhydrologicalconditions, thediurnalevolutionofCd,CuandPb intheRiou-Mortriver (France) im-pactedbypolymetallicpollutionresultingfromformeropen-castcoalminingandoretreatment.Thisanalyzerisbasedonabioanalogicmicrosensorwhichallowsinsitureal-timemonitoringofthedynamicfraction,i.e.thepotentiallybioavailablefraction,ofthetargetanalytes.Inparallel,T,pH,dissolvedoxygenandconductivityweremonitoredinsituandwatersam-pleswerecollectedforcomplementaryanalysesofthewatercomposition.

Severaloriginalresultswereobtained.Thedatarevealedthat,inthestudiedriver,thediurnalcyclesoftheCd,CuandPbdynamicspecieswerecontrolledbyredoxandsorptioneffectsinducedbyeither:pHdiurnalcyclelinkedtometabolicactiv-ity of benthicbiofilms; photoreductionof colloidalMnoxides; and/orbiofilmexudationof extracellularpolymeric sub-stances.Wealsoobservedthat:thedynamicfractionofagivencationicmetalcanshowdiurnalcyclewithoppositetrendsdependingonthebio-chemicalconditions; thetrendsof thediurnaldynamicmetalspeciescyclesmaybedifferentthatthosereportedforthedissolvedmetalspecies.Theimportanceofthesefindingswillbediscussedinthecontextofinterpret-ingexistingdatabanks,assessingmetalecotoxicityimpact,anddesigningmoreappropriatemonitoringcontrolstrategies.

REFERENCESTercier-Waeber,M.-L.&Taillefert,M. 2008:Remote in situ voltammetric techniques to characterize thebiogeochemical

cyclingoftracemetalsinaquaticsystems.J.Environ.Monit.,10,30-54.Tercier-Waeber,M.-L.,Hezard,T.,Masson,M.,&SchäferJ.2009:Insitumonioringofthediurnalcyclingofdynamicmetal

species ina streamunder contrasting photobenthicbiofilmactivity andhydrological conditions,Env. Sci. Technol.,DOI:10.1021/es900247y.

3.39

LAMBERN – software for U-Pb, Th-Pb and Pb-Pb age dating by LA-ICP-MS analysis

ThomsenTonnyB.*,PettkeThomas*,AllazJulien*’**&EngiMartin*

* University of Bern, Institute of Geological Sciences, Baltzerstrasse 1+3, CH-3012. (thomsen@geo.unibe.ch)** University of Massachusetts Amherst, Department of Geosciences, 611 North Pleasant Street, USA

ForU-Pb,Th-PbandPb-Pbagedating,theLA-ICP-MSoffersacostreducingandtimeefficienttechniquecomparedtoe.g.TIMSandSIMS,bywhichabulkofdatawithamoderateprecision(typically<2%)canbeobtainedinaveryshorttime(e.g.50-100agesin1-2days).Tocomparetheobtaineddata,standardizedprotocolsacceptedbytheLA-ICP-MSagedatingcommunityandassociatedsoftwareabletohandleandcalculateagesfromthevarioussolidphasesarerequired.Atpresent,littlesoft-

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y wareisavailable(e.g.LAMTRACE,GLITTER,Lamdate,PEPITA,ComPbCorr,PbI;summarizedinKoЄler&Sylvester,2003andKošleretal.,2008).SomeoftheseassumenoinitialPbpresent(LAMTRACE,GLITTER),however,somegeologicallyrelevantminerals such as allanite, titanite, rutile andperovskitemay contain a significantproportionof commonPb.Other ap-proachesrelyonanebulization-inducedspikebracketingtechnique(Lamdate),anapproachthatisnotemployedinalllabo-ratories.Thus,wepresenthereatransparent,step-by-stepExcel-baseddatareductionprocedureforin-situsolidstateU-Th-Pb-basedagedeterminationsbyLA-ICP-MS.Thesoftware(calledLAMBERN)isabletohandleallsolidphaseswithsufficientU,ThandPbcontentforagedatingbyLA-ICP-MS,includingphaseswithasignificantcommonPbproportion.Thesoftwareoffersfullcontrolinallstepsoftheconsecutiveandflexibledatareductionapproach(includesseveraloptionsfordatacorrectionandagecalculationprocedure).Alldatatreatment,agecalculationanderrorpropagationarecarriedoutinasingleExcelfile.Variousdiagrams,includingtime-intensity,time-ratio,sensitivity,ablationyield,Concordia,Tera-Wasserburgaregenerated.TheoutputcanbereaddirectlybyIsoPlotEx(Ludwig,2003)foradditionalplottingandcalculations.LAMBERNemploysastandard-sample-standardbracketingapproachwithamaximumof20individualanalysesimportedthroughanintegratedVBAmacroofxl,txtorcsvfiles(fromElan,ThermoFinniganElement2orThermoX).Timeintervalsforbackgroundandsignalareselectedbytheuser.Screeningofthesignalsforextremevalues(technicallyinduced“outli-ers”)andforsignalsofpoorquality(e.g.fromtime-dependantfractionation)iscarriedoutthroughtime-intensityandtime-ratiodiagramsandincludesanoptionfortherejectionofdatafromatoleratedrelativestandarddeviation(Є)specifiedbytheuser.Therejectionofdataincludesentiresweeps.Optionsforthedatacorrectionisspecifiedinthesetupparameterssectionandincludebackgroundcorrection,mercuryinterferencecorrection(of204Hgon204Pb),correctionforinstrumentalmassbias(Linear,PowerandExponentialLaws,RussellandBaxterformulations),detectordriftand3differentcommonPbcorrectionroutines(measured204andthe“207Pb”and“208Pb”corrections).Matrixeffectscalibrationcanbeappliedifrequired.Selectionisdonebetween(i)non-matchedmatrixbasedone.g.NISTSRM-610glassor(ii)matrixmatchingemployingoneormore(in-house)referencematerialsofknownage(e.g.Harvard91500zirconforanalysisofzirconsofunknownage).Atpresent,therobustnessofthescreeningandcalculationproceduresinLAMBERNarebeingtestedthroughanalysesofstandard zircons (91500zircon, Temora-1, Plesovice), allanites (AVC, CAP, Tara, Daibosatsu, Bona, Sissonne), titanite andmonazite(in-housestandards).Ingeneral,theaccuracyofnon-matrixmatchedcalibrationroutinesforzircon,allaniteandinparttitanitereportupto30%deviationfrom“true”ages(e.g.TIMS,SIMS).Thus,matrix-matchedcalibrationisemployed.Atthetimeofreporting,LAMBERNhasbeeninusebyonlyahandfuloftest-users,thusisa“beta”version.

REFERENCESKošlerJ.,ForstL.&SlámaJ.(2008)LamDateandLamTool:spreadsheet-baseddatareduc-tionforlaserablationICP–MS315.

InSylvesterP.(ad)LaserAblation–ICP–MSintheEarthSciences,CurrentPracticesandoutstandingissues,AppendixA4:SoftwareforReductionofLA–ICP–MSData.MACShortCourseSeries40,305-306.

Košler, J.&Sylvester,P.2003.Presenttrendsandthefutureofzirconingeochronology: la-serablationICPMS.ReviewsinMineralogy&Geochemistry,53,243-275.

Ludwig,K.R.(2003)IsoplotExv.3.0.BerkeleyGeochronologicalCenter.

3.40

First insights into the dehydration of lizardite

TrittschackRoy&GrobétyBernard

University of Fribourg, Department of Geosciences, Chemin du Musée 6, CH-1700 Fribourg (roy.trittschack@unifr.ch)

LizarditeMg3Si

2O

5(OH)

4 isa trioctahedral1:1phyllosilicate,whichbelongs togetherwithchrysotileandantigorite to the

serpentinemineralgroup.Thestructureoflizardite,basedonsimpleflatlyingT-O,ismuchsimplercomparedtothecor-rugatedandcylindricalstructuresofantigoriteandchrysotilerespectively.Lizarditeis,therefore,thelogicstartingpointinanattempttounderstandthedehydrationprocessesandratesofthismineralgroup.Theaimofthisstudyistounderstandtheratedeterminingstepsandthekineticsofthedehydrationoflizardite.Thedehy-drationimpliesthedeprotonationofpartofthehydroxylgroupsandrecombinationofthehydrogenionwithneighbouringhydroxylgroupstoformawatermolecule.Thesecondstepisthetransportofthewatermoleculeouttothesurface.High-temperature experiments like in-situ HT-XRD and in-situ IR spectroscopy are ideally suited to investigate the structuralchangesduringthereaction.ExploratoryIRexperimentsandXRDstudiesonlizarditeunderroomconditionsgavestartingtemperaturesforthedehydrationbetween500°Cand550°CwhichliesintherangeofformerinvestigationsbyBrindley&Zussman(1957)andFranketal.(2005).Theinitialproductofdehydrationisamorphous,whichcrystallizesafteracertaintime

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trytoforsteritefollowedbyenstatite.Assumingproportionalitybetweentheintegralintensityofhkl-peaksandtheamountof

lizarditepresent, thereactionratecanbeextracted fromtherateof intensitydecrease.Thedatawillbe treatedwiththeconventionalAvramimethodaswellasthesocalled“timetoagivenfraction”(TGF)method.OnemajoradvantageoftheTGFmethod is thepossibility todiscover changes in theactivationenergyE

aduring the courseofdehydration (Putnis, 1992).

Knownvaluesfortheactivationenergyoflizarditederivedfromdifferentialthermalanalyses(DTA)andlyingaround350kJmol-1(Weber&Greer,1965),whichisratherlargecomparedwithotherphyllosilicateswithvaluesaround200kJmol-1.

REFERENCESBrindley,G.W.&Zussman, J.1957:Astructural studyof the thermal transformationof serpentineminerals to forsterite.

AmericanMineralogist,Vol.42(7-8),461-474.Frank,M.R.,Earnest,D.J.,Candela,P.A.,Wylie,A.G.,Wilmot,M.S.&Maglio,S.J.2005(abstract):Experimentalstudyofthe

thermaldecompositionoflizarditeupto973K,SaltLakeCityAnnualMeeting2005Putnis,A.1992:IntroductiontoMineralSciences,CampridgeUniversityPress,457p.Weber,J.N.&Greer,R.T.1965:Dehydrationofserpentine-HeatofreactionandreactionkineticsatPH2O=1Atm.American

Mineralogist,Vol.50(3-4),450-464.

3.41

Analytical and numerical description of tephra deposition: the example of two large explosive eruptions of Cotopaxi Volcano, Ecuador

TsunematsuKae*,BonadonnaCostanza*,FalconeJean-Luc**&ChopardBastien**

*Départment de Minéralogie, Université de Genève, Rue de Maraîchaire 13, CH-1205 Genève** Départment d’Informatique, Université de Genève, Battelle, Building A, Carouge; 7 route de Drize, CH-1227 Carouge

ThedownwindandcrosswindtephradepositionwasstudiedindetailfortwolargeexplosiveeruptionsofCotopaxivolcano,Ecuador(apumiceousunit,Layer3,andascoriaceousunit,Layer5;Barberietal.1995).Thetwoeruptionswerecharacterizedbyasimilarplumeheight,i.e.28±2kmforLayer3and28±0kmforLayer5,butLayer3wascharacterizedbyalargervolu-me,i.e.1.5km3forLayer3and0.3km3forLayer5(BiassandBonadonna,submitted).Thetwolayersarecharacterizedbysi-milartotalgrainsizedistribution(MdΦ:~-2),butLayer3tephrawasadvectedbyastrongerwind(28m/sforLayer3and21m/sforLayer5).Asaresult,crosswindvariationofgrainsizeisconsistentforthetwolayers,butatanygivendistancefromventdownwinddepositioniscoarserforLayer3(Figure1).TheincreaserateofMdΦisabout0.2forbothlayers(Figure1a).

WehaveimplementedboththemodelofBonadonnaandPhillips(2003)fortephradispersalfromstrongvolcanicplumesandtheCellularAutomatamodelofTsunematsuetal.(2008)todescribecrosswindtephradepositionbasedonaGaussiandistribution.Inaddition,wehavealsoimplementedthemodelofTsunematsuetal.(2008)toaccountforsedimentationfromthebottomoftheumbrellacloudassupposedtoapoint-sourceparticleconsideringthefollowingequation(BonadonnaandPhillips2003):

−= ∫x

xdx

Qvw

MM0

exp0

(1)

whereM (kg)isthetotalmassofparticlesofagivensizefractionatthebottomofthespreadingcurrent,M0(kg)istheiniti-

almassinjectedintothespreadingcurrent,Qisthevolumetricflowrate,vistheterminalvelocityoftheparticleofgivengrainsize,w isthemaximumcrosswindwidthandx isthedistancefromtheplume.BoththemodelofBonadonnaandPhillips(2003)andTsunematsuetal.(2008)hadshowngoodagreementwithtephradepositionobservedalongthedispersalaxisforanumberoferuptions.However,thecrosswinddepositionhadnotbeeninvestigatedindetail.

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(a) (b)

Figure1.Medianofgrainsizedistributionalongdownwindaxes(a)andcrosswindaxes(b).PinktrianglesaredataforLayer3andblue

squaresaredataforLayer5.Forthedownwinddata,linearregressionsarecalculatedforeachlayer.PinklineisforLayer3andblueline

isforLayer5.

REFERENCESBarberi,F.,Coltelli,M.,Frullani,A.,RosiM.,&Almeida,E.1995:Chronologyanddispersalcharacteristicsofrecently (last

5000years)eruptedtephraofCotopaxi(Ecuador):implicationsforlong-termeruptiveforecasting.JVGR,69,217-239.BiassS.&BonadonnaC.,(inpreparation)Aquantitativeuncertaintyassessmentoferuptiveparametersderivedfromtephra

deposits.Bonadonna C. & Phillips J. C. 2003: Sedimentation from strong volcanic plumes. JGR. 108. B7, 2340, doi:10.1029/

2002JB002034.TsunematsuK, Falcone JL, BonadonnaC&Chopard B. 2008: Applying aCellularAutomataMethod for the Study of

TransportandDepositionofVolcanicParticlesH.LectureNotesinComputerScience(LNCS).vol.5191,393-400.

3.42

Petrology of mafic-ultramafic complexes within the Archean Lewisian complex of NW Scotland

UdryArya*,MüntenerOthmar*,

* Institute of Mineralogy and Geochemistry, University of Lausanne, Anthropole, CH-1015 Lausanne (arya.udry@unil.ch)

TheLewisiancomplexisafragmentoftheancientLaurentiancontinentalmass,thesouthernextension,whichisnowbur-iedbeneaththemetasedimentsoftheScottishhighlands.TheArcheangneissesoftheLewisiancomplexrepresentalong,andcomplexpartofEarthhistory.TheareaofinterestisinNorthwesternScotland,betweenLochLaxfordandLochInver.Theterrainconsistsmostlyofbandedgneisseswithavarietyofbasictoultrabasicbodies.Thegneissesarebandedwithalternatingacidandmaficlayers.Granulitefaciesparagenesesarecommon.Largebodiesofultrabasicrockscontainvariableproportionsofolivine,pyroxene,spinel,plagioclaseandhornblende,whereasbasicbodiesareessentiallymadeofpyroxene,hornblende,plagioclaseandgarnetbear-ingassemblages.ThisstudyfocusesontwoofthesecomplexesnearDrumbegandnearScourie.Thesebodiesaredescribedaslayered‘meta’intrusivesandareembeddedwithintonalitictogranodioriticgneisses.Isotopicstudiesindicatethatthegneissesderivedfrommagmasthatseparatedfromthemantleabout2.9Ga(Moorbathandal.1969;Hamiltonandal.1979)andthehighgrademetamorphismwascompletedbyabout2.7Ga(ChapmanandMoorbath1977).Laterdikes(Scouriedikes)aredatedat2.4Ga(Chapman1979),followedbyretrogradeamphibolitefaciesmetamor-phismandinjectionofgranitesandpegmatitesatabout1.8Ga.(JohnstoneandMykura1989).Severalhypotheseshavebeenputforwardabouttheformationofthoseultramaficandmaficbodies,butithasbeendemons-tratedthatvoluminousgranodioriteandtonalitesurroundingrocksareofcalc-alkalineaffinity,whichisgenerallyinferredto be important in subduction zone environments. After Park and Tarney (1987), gneisses represents continental crustformedduringsubductionandthemafic-ultramaficassociationrepresentsmaterial intercalatedtectonicallyduringpro-cessesofcrustalgeneration,probablyfromsubductingoceanfloor.Thisinterpretationmightbedebated.Weevaluatethehypothesiswhether such rockassociations couldbe related to crystallization fromH

2O-richmagmaswithinanArchean

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trysubductionzoneenvironment,oralternatively,whethertheycouldberelatedtometamorphoseddryplutonicrockswithin

theArcheancrust,byapplyingnewmappingandsystematicallyinvestigatingmineralchemicalmajorandtraceelementdata.Itisentirelyunknown,whetherprimaryigneousphasesarestillpresent(e.g.Sillsetal.1982)andapparentgranulitefacies“metamorphic”texturesmasktheigneouscrystallisationhistoryofthishighpressurerocks.However,withtheapplicationofnewin-situmethodssuchasLaserAblationICP-MS,newresultsonthemainmineralsandwholerockswereobtained.Inaddition,wewilldeterminein-situthemajorandtraceelementdistributionofthemajormineralphasesthatshouldprovi-deadditionalconstraintsontheequilibrationhistoryoftheserocks.Wefocusonelementsdistributionsandgarnetszona-tionsandtrytoevaluateamagmaticvsmetamorphicorigin.Wepresentpreliminary resultson the thermalevolutionofmafic-ultramafic systemswithingranulite facieshost rocks.TestingthehypothesisofanarcoriginisnotonlyanimportantquestionforabetterunderstandingoftheArcheanLewisiancomplex,butmuchmoresofortheimportancehowsubductionprocessesworkedintheArchean.

REFERENCESChapman,H.J.(1979):2390M.yrRb-SrwholerockisochronfortheScouriedykesofNWScotland.Nature,277,642ChapmanH.J.,MoorbathS.(1977):LeadisotopemeasurementsfromtheoldestrecognizedLewisiangneissesofnorth-west

Scotland.Nature,268,41-42HamiltonP.J., EvensenN.M.,O’NionsR.K., Tarney J. (1979): Sm-Nd systematicsof Lewisiangneisses : implications for the

originofgranulites.Nature,277,25-28Johnstone,G.S. andMykura,W. (1989):British regionalgeology: thenorthernHighlandsof Scotland (4th edition). British

GeologicalSurvey,pp219Moorbath S.,WelkeH.,GaleN.H. (1969): The significance of lead isotope studies in ancient, highgrademetamorphic

basementcomplexes,asexemplifiedbytheLewisianrocksofNorthwestScotland.EarthPlanetSciLett,6,245-256Park,R.G.andTarney,J.(1987):TheLewisiancomplex:atypicalPrecambrianhigh-gradeterrain?EvolutionoftheLewisian

andcomparablePrecambrianhighgradeterrains,GeologicalSocietyPublication,27,13-25Sills,J.D.,Savage,D.,Watson,J.V.,andWindley,B.F.(1982):Layeredultramafic-gabbrobodiesintheLewisianofnorthwest

Scotland:geochemistryandpetrogenesis.EarthandPlanetaryScienceLetters,58,345-360

3.43

Iridium-strip heater glass pellets: Effects of fusion temperature and time on Li, Be and B content

VilsFlurin*,DijkstraArjan*,LaurePelletier*,ThomasLudwig**&AngelikaKalt*

*Institut de Géologie et d’Hyrogéologie, Rue Emile-Argand 11, Cp158, 2009-Neuchâtel (f lurin.vils@unine.ch)**Institut für Geowissenschaften, Im Neuenheimer Feld 236, D-69120 Heidelberg

Tosolveabroadrangeofgeochemicalproblems,preciseandaccuratewholerockandtraceelementanalysesarerequired.EspeciallyinthecaseoflowabundantelementslikeLi,BeandB,whicharewidelyusedastracersofalteration,subductionandrecyclingprocessesintheEarth,thisisacriticalissue.Forin-situmineralmeasurementsoftheseelements,secondaryionmassspectrometry(SIMS)isprobablythemostsensitiveandmostaccurate.AmethodthatallowstoanalysewholerocklightelementconcentrationsusingSIMSwouldbeextremelypowerfulandwoulddramaticallyincreasesamplethroughput.However,amethodtomeasurewholerockcontentsofallthreelightelementstogetherismissingsofar.AnIridium-stripheaterprovidesafluxfreemethodtofusedirectlyhomogeneousglasspelletsfrompowderedrocks.Thesepelletscanbe investigatedformajorandlightelementsusingmicrobeam(electron, ionor laser)methods.Wehavecon-ductedexperimentsunderdifferentfusiontemperatures(1500-1800°C)andtime(30-240s)onselectedsamplesrepresentingawidevarietyofLi(0.91to56.5µg/g),Be(0.24to3.5µg/g)andBcontent(2.18to12µg/g).Westudiedthebehaviourofthethreeelementswithrespecttothedifferentcompositions,fusiontimeandtemperature.Homogeneitywithinthefusedglassesisgenerallyreachedunderthestudiedconditionsformostelements.Electronmicro-probemeasuresandelementdistributionmapsconfirmthishomogeneity.Lightelementmeasurementsshowedhomogene-ous behaviour for Li and Be (RSD of 3%, 6% respectively), but B is significantly less homogeneous (average RSD of 31%).HeatingtimedependentlossofLi,BeandBoccursthroughoutallstudiedsamples,butBeandLilossisalwayswithinana-lytical errorsof theusedmethods (generally <10%). SignificantB lossduring fusion is found inalmost every sample. Ingeneral,Bisshowinghighlyvolatilebehaviour,andat1800°CmostBhasevaporated.Clearly,flux-lesspreparationofwholerockglassesisnotaviablemethodforBanalysisbecauseofitsvolatility,butthemethodiswell-suitedforLiandBe.

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Molybdenum isotopes in modern corals: investigation into their potential as redox proxy of bygone oceans

Voegelin,AndreaR.*,Samankassou,Elias*&Nägler,ThomasF.**

* Départment de Géologie et Paléontologie, Université de Genève, Rue des Maraîchaire 13, CH-1205 Genève (andrea.voegelin@unige.ch)**InstitutfürGeologie,UniversitätBern,Baltzerstrasse1+3,CH-3012Bern

PeriodsofmarineO2deficiencyareimportantfeaturesofEarthhistory,inparticularforclimateandtheevolutionoflife.

Theoxygenationstateofpaleo-environmentsiscloselyconnectedtothecyclingofredoxsensitiveelements.Hence,thein-terpretationofpastchangesinoceanicredoxchemistrydependsontheidentificationofgeochemicalproxieswhichprovideareliablefingerprintofpastseawatercompositions.

Inrecentyearsthemolybdenumisotopesystemhasattractedsignificantattentionandhasproventobeusefulintheinve-stigationoftheextentofsea-flooranoxiainthegeologicalpast(e.g.Arnoldetal.,2004,Willeetal.,2008,Pearceetal.,2008).CarbonaterockshavejustrecentlybeenintroducedaspromisingnewMoisotopearchive(Voegelinetal.,2009).ItwasshownthatMouptakeintonon-skeletalcarbonateprecipitatesisaccompaniedbyminorisotopefractionation.Consequently,theywereproposedasamonitoroftheambientfluidcomposition,which,underfavorableconditions,maycloselyreflecttheoceanwaterδ98/95Moofbygoneoceans.Theapplicationofskeletalcarbonateiscomplicatedbybiologicallycontrolledisotopefractionation,whichmaycompletelyobliteratetheoriginaloceanwatersignature(Voegelin,2009).Sofar,onlywellpreser-vedmodernaragoniticcoralshaverevealedtoexhibitaconsistentlysmalloffsetfromseawater.TheymaythusprovidethemeanstoobtainawelldatedandnearlycontinuousreconstructionoftheMoisotopiccompositionofpastoceansfromtheHoloceneasfarbackasOrdoviciantimes.Theirapplicationaspaleo-oceanographictool,however,dependsonthepreserva-tionofanoceanwatersignatureduringdiageneticprocesses,especiallythereplacementofmeta-stableskeletalaragonitewithcalcite.

Thisstudyinvestigatesunalteredcoralmatricesanddiageneticallymodifiedmaterialinordertoassesspossiblepost-depo-sitionalMoisotopeandtraceelementexchangeprocessesandtheirimplicationsforthefutureuseofcoralsasMoarchive.

REFERENCESArnold,G. L.,Anbar,A.D.,Barling, J.& Lyons,T.W,2004:Molybdenum isotopeevidence forwidespreadanoxia inmid-

Proterozoicoceans.Science,304,87-90.Pearce,C.R.,Cohen,A.S.,Coe,A.L.&Burton,K.W.,2008:Molybdenumisotopeevidenceforglobaloceananoxiacoupled

withperturbationstothecarboncycleduringtheearlyJurassic.Geology,26(3),231-234.Voegelin,A. R.,Nägler, T. F., Samankassou, E.& Villa, I.M., 2009:Molybdenum isotopic composition ofmodern and

Carboniferouscarbonates.ChemicalGeology,265,488-498.Wille,M.,Nägler,T.F.,Lehmann,B.,Schröder,S.&Kramers,J.D.,2008:Hydrogensuphidereleasetosurfacewaterstthe

Precambrian/Cambrianboundary.Nature,453,767-7.

3.45

Effect of minor elements (H+ and Al3+) on the elastic properties of ortho-pyroxenes

JingyunWang*,CarmenSanchez-Valle*&RolandStalder**

* ETH, Inst Mineral & Petrol, CH-8092 Zurich (jingyun.wang@erdw.ethz.ch)** Innsbruck Univ, Inst Mineral & Petrog, A-6020 Innsbruck, Austria

Orthopyroxenes (Opx), along with olivine, garnets and clinopyroxenes, are major components of the upper mantle.KnowledgeofthechangesinseismicvelocitiesandelasticpropertiesofOpxasafunctionofcompositionisthereforeessen-tialtobuildupmineralogicalmodelsoftheuppermantleandtointerpretheterogeneitiesinthemantlerevealedbyhigh-

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tionoverthepastyears,theinfluenceofminorelementsubstitutionsontheelasticpropertiesoforthopyroxeneshasbeenlessinvestigated.

HerewepresentBrillouinscatteringmeasurementsofthesingle-crystalelasticpropertiesofsynthetichydrousaluminum-freeandhydrousaluminum-bearingorthopyroxenes(hereafterreferredtoasHyOpxandAlOpx,respectively)underambientconditions. The samples were synthesized at 2.5 GPa and 1150 °C in piston-cylinder apparatus. HyOpx contains minoramountsofH+(280ppmH

2O)whileAlOpxhasasimilarAl

2O

3content(6.3wt%)tothatofnaturalOpx,andminoramounts

ofH+(1500ppmH2O),andFe(0.26wt%FeO).Theaggregatebulk(K

S)andshear(µ)elasticmoduliofHyOpx,K

S=108.5(9)GPa

andµ=77.0(4)GPa,areindistinguishablefromthoseofanhydrousorthoenstatite.TheresultssuggestthatincorporationofH

2Oupto280ppmhasnosignificantinfluenceonelasticpropertiesofMgSiO

3-orthoenstatite.Theaggregateelasticmoduli

ofAlOpx,KS=126.2(1.2)GPaandµ=81.3(8)GPa,arerespectively14.7and6%higherthanthoseofpureMgSiO

3-orthoenstatite.

TheseresultsconfirmthatthestiffeningofthebulkmodulusreportedinnaturalOpxrelativetoMg-end-membersismain-lyduetothesubstitutionofAlforsmallerSiintetrahedralsites.ThisconclusionissupportedbythestrongincreaseintheC

33 elastic constant upon Al substitution that reflects the stiffening of the tetrahedral chains running along c-axis.

Consequently,theaggregatevelocitiesofAlOpx,VP=8.50(9)km/sandV

S=5.01(6)km/s,are7%and4%higherthanthoseof

themagnesianend-member.TheresultsindicatethatAlhasthestrongesteffectontheseismicvelocitiesofOpxofallminorelementsandmaybetakenintoaccounttorefinecompositionalandmineralogicalmodelsoftheuppermantle.

3.46

Deciphering the Alpine orogenic and thermal evolution from subduction to collision: Raman spectroscopy and 40Ar/39Ar age constraints from the Valaisan Ocean (Central Alps)

WiederkehrMichael*,BousquetRomain**,SudoMasafumi**,ZiemannMartinA.**,BergerAlfons***&SchmidStefanM.****

*Bundesamt für Landestopografie swisstopo, Landesgeologie, Seftigenstrasse 264, CH-3084 Wabern, Switzerland(michael.wiederkehr@swisstopo.ch)**InstitutfürGeowissenschaften,UniversitätPotsdam,Karl-Liebknecht-Strasse24/25,D-14476Potsdam/Golm,Germany***InstitutforGeografiogGeologi,KøbenhavnsUniversitet,ØsterVoldgade10,DK-1350KøbenhavnK,Denmark****InstitutfürGeologischeWissenschaften,FreieUniversität,Malteserstrasse74-100,D-12249Berlin,Germany

ThemetasedimentsoftheValaisanOceanandtheadjacentdistalEuropeanmargin,exposedbetweenthePizzoMolare/Passodi Lucomagnoareaand thePrättigauhalf-windowshowa remarkablemetamorphicgradient:Carpholitebearingassem-blagesintheeastindicatepressuredominatedblueschistfaciesmetamorphism.Furtherwestthesameunitsarecharacteri-zedbyatemperaturedominatedBarrovianamphibolitefaciesmetamorphism(“Lepontine”metamorphism).Therelation-ships between deformation and metamorphism indicate two distinct metamorphic events: a late-stage Barrowian(“Lepontine”) event clearly overprints an earlier HP/LT event. This is independently confirmed by a bimodal P-T path(Wiederkehretal.,2008).Tounravelthispoly-metamorphicevolutionweperformeddetailedinvestigationsofcarbonaceousmatterbyRamanspectroscopyinordertomonitorthespatialdistributionofpeak-metamorphictemperatures.Additionally,weperformed40Ar/39Ardatingofmicabyusingin-situandstep-wise-heatingtechniquesinordertodecipherthetemporalrelationshipsbetweenthesetwometamorphicevents.Thenewdatayieldimportantinsightregardingthetransitionfromsubductiontocollision,bothonthescaleofthetectonicunitsderivedfromtheValaisanpaleogeographicaldomainandonthescaleoftheentireorogenicbelt.

TheresultsofRamanspectroscopy,performedonatotalof214samples,allowforhighresolutionmappingofthemaximummetamorphictemperaturesreachedinthesesamplesinthreedimensions.Suchthree-dimensionalmappingoftheisotem-peraturecontours inmapandprofileviewfaithfullyreflects thepresent-daydistributionofpeak-metamorphic tempera-tures.Thetemperaturegradientsresultedfromasuperpositionofatleastthreedistinctmetamorphicevents(Wiederkehretal.,submitted).(1)WithinthenortheasternrimoftheLepontinedome-bothalongandacrossstrike-theisotemperaturecontoursinthe450-570°Ctemperatureintervalareassociatedwiththecollision-relatedlate-stageBarrow-typeevent.Theyclearlycutacrossnappecontactsandmega-foldsdeformingsucholdertectoniccontacts.(2)FurthertotheNEthe350-425°Cisotemperaturecontoursreflecttemperaturesreachedduringanearlierblueschistfacieseventand/orsubsequentnear-isothermal decompression. They are folded by large-scale post-nappe stackingmega-folds. (3) A substantial “temperaturejump”acrossthetectoniccontactbetweenthefrontalAdulanappecomplex(500-520°C)andthesurroundingValaisan-de-

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y rivedmetasediments(410-430°C)indicatesthat,incontrasttothepostulatesraisedbyearlierstudies,equilibrationoftem-peraturesduringthelate-stageLepontineeventisincompleteinthisarea.

The dating of high-pressuremetamorphism, subsequent retrogression and final Barrow-type overprint was obtained by40Ar/39Ardatingofbiotiteanddifferentwhitemicagenerationsthatareallwellcharacterizedintermsofmineralchemistry,textureandassociatedmineralassemblages(Wiederkehretal.,inpress).Fourdistinctagepopulationsofwhitemicarecordpeak-pressureconditionsat42-40Ma,followedbyseveralstagesofaretrogrademetamorphicevolution,predominantlyde-compression,between36and25Ma.Biotiteisotopicanalysesyieldconsistentapparentagesthatclusteraround18-16MafortheBarrow-type thermal overprint thatwas associatedwith the temperature increase that followeddecompression. Theisotopicdatarevealasignificanttimegapintheorderofsome20Mabetweenthesubduction-relatedHP/LTevent(42-40Ma)andthelatercollision-relatedMP/MTBarrovianoverprint(19-18Ma).Thissubstantialtimegap,togetherwiththeagecons-traintsonwhitemicareflectingtheretrogrademetamorphicevolutionoftheHP/LTstage,supportthenotionofapoly-me-tamorphicevolutionassociatedwithabimodalP-Tpath.AmphibolitefaciesBarrow-typeoverprintoftheNELepontinedomeclearlyrepresentsaseparateheatingpulsethatpost-datesisothermaldecompressionafterthehigh-pressurestage.Thisin-dicatesthatitistheaccretionofvastamountsofEuropeancontinentalcrustformingthepresent-dayLepontinedomethatprovideshigh radiogenicheatproduction responsible for amphibolite faciesmetamorphism (Bousquet et al., 2008]. Thisheatingisanentirelyconductiveandthereforeratherslowprocess.

REFERENCESBousquet,R.,Oberhänsli,R.,Goffé,B.,Wiederkehr,M.,Koller,F.,Schmid,S.M.,Schuster,R.,Engi,M.,Berger,A.&Martinotti,

G.2008:Metamorphismofmetasedimentsatthescaleofanorogen:AkeytotheTertiarygeodynamicevolutionoftheAlps.In:S.Siegesmundetal.(eds.)TectonicAspectsoftheAlpine-Dinaride-Carpathiansystem,Geol.Soc.SpecialPubl.,298,393-411.

Wiederkehr,M.,Bousquet,R., Schmid, S.M.&Berger,A. 2008: Fromsubduction to collision:ThermaloverprintofHP/LTmeta-sedimentsinthenorth-easternLepontineDome(SwissAlps)andconsequencesregardingthetectono-metamorphicevolutionoftheAlpineorogenicwedge.In:N.Froitzheim&S.M.Schmid(eds.)OrogenicprocessesintheAlpinecollisionzone,SwissJ.Geosci.,101(Suppl),S127-S155.

Wiederkehr,M.,Sudo,M.,Bousquet,R.,Berger,A.&Schmid,S.M.inpress:Alpineorogenicevolutionfromsubductiontocollisionalthermaloverprint:40Ar/39ArageconstraintsfromtheValaisanOcean(CentralAlps),Tectonics.

Wiederkehr,M.,Bousquet,R., ZiemannM.A.,Berger,A.&Schmid, S.M. submitted: 3-Dassessmentofpeak-metamorphicconditionsbyRamanspectroscopyofcarbonaceousmaterial:anexamplefromthemarginoftheLepontinedome(SwissCentralAlps),submittedtoContrib.Mineral.Petrol.

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Approximate terrestrial age dating of meteorites by use of handheld XRF

ZurfluhFlorian*,HofmannBeda**,GnosEdwin***,EggenbergerUrs*&OpitzChristoph**

*Institut für Geologie, Baltzerstrasse 1+3, CH-3012 Bern (f lorian.zurfluh@geo.unibe.ch)**Naturhistorisches Museum Bern, Bernastrasse 15, CH-3005 Bern***Muséum d’Histoire naturelle, route de Malagnou 1, CP 6434, CH-1211 Genève

DuringalargeprojectforsystematicmeteoritesearchinthehotdesertoftheSultanateofOmanwehavesofarcollected5237samplesthatrepresent~550fallevents.Thisis,besidestheAntarcticcollection,thelargestwell-characterisedmeteoritepopulation.Ourmaingoalsaretoevaluatestatisticallyourfindsandstudytheweatheringandcontaminationeffectsofthesamplesduringtheirterrestrialresidence.Forthesepurposesweneedtoknowhowlongthemeteoritesareonearth.Usuallytheterrestrialageisdeterminedby14Cmeasurements(e.g.Jull2006).Buttheseanalysesaretimeconsumingandthereisnochancetomeasureallcollectedsamples.FormerstudieshaveshownacontinuousuptakeofSrandBaduringtheterrestrialsojournofmeteorites(e.g.Al-Kathirietal.2005).WetrytocalibrateanagescaleforfastdatingofOmanimeteoritesbyuseofSrcontentsmeasuredwithhandheldXRF.

WeuseaNitonXL3t-600handheldXRFanalyserforfastandnon-destructivemeasurementsofnearlyallelementsbetweenKandU,withaspecialfocusonFe,Mn,Ni,CaandtheweatheringproxySr.Thisinstrumenthasapredefinedmeasurementmodefortraceelementsinmediumconcentrations.TestswithinternationalandownmeteoritestandardsmeasuredwithICP-MSandhandheldXRFconfirmedanaccuracyofSrmeasurementswiththis“soilmode”withinaderivationof±13%atcountingtimesof120seconds.InitialSrcontentsinordinarychondrites,themostabundantgroupofmeteorites,arebe-tween10and11.1ppm(Wasson&Kallemeyn1988)whereastheycanreachvaluesofseveralthousandppmduringweather-ingandcontamination.Anothereffectmightbeusefulforrelativedating:inhotdesertsoccursanaccumulationofMn-richmaterialduringexpo-suretimeonsomerocks.ItisalsopossibletoquantifythisdesertvarnishwithhandheldXRF.

Measurementswereperformedoncut-(C),exposed-(E)andburied-surfaces(V)ofmeteoritesfromfivelargestrewnfieldsandsomeindividualsamplescollectedontwomajormeteoriterecoverysurfacesintheSultanateofOman,theDhofar(Dho)/ShisrregionandJiddatalHarasis (JaH)/SayhalUhaymir(SaU).TheinfluenceofthesoilisevidentbutalotofanalysisofOmanidesertsoilsamplesdeliveredlowvariationsforSrconcentrationssomewherebetween250to350ppm(Al-Kathirietal.2005).Fromeachstrewnfieldsevento25sampleswereanalysedonthethreementionedsurfaces(C,EandV).Eachsurfacewasmeasuredforatleastthreetimestominimiseeffectsoflocalinhomogeneities.

Theresultsofthissurveywerecomparedwith14CagesfromAl-Kathirietal.(2005).Thesamplesfromtheyoungeststrewnfield,SaU001,haveingeneralthelowestSrcontents.Asonewouldexpectthehighestvaluesaremeasuredontheoutersurfaces(V)ofthesamplesthatwereburiedinthesoil,approvethecontaminationofthemeteoriteswithSrfromthesoil.Theyoungandmediumagesamples(SaU001,JaH073&JaH091)havehighdifferencesbetweentheouter(E,V)andtheinte-rior(C)Srconcentrationswhereastheoldersamples(Shisr015&Dho005)haveamorebalancedratiobetweenthesurfaces.AcontinuousdiffusionofSrfromtheexteriortotheinteriorisaplausibleexplanationforthiseffect.Thecutsurfacesdeliverthebestvaluesforanapproximateagedating.ThereisaninconsistencybetweentheSrcontentsatthecutsurfaceandthe14CageofthetwoJaHstrewnfields.Sincetheseareextremelylargestrewnfields,shieldingeffectscouldhavefalsifiedtheradiocarbonage(Gnosetal.2006,2009).Theyounger“Srage”oftheJaH091issupportedbyagen-erallowerdegreeofweatheringobservedinthinsection.AdditionallytheJaH073sampleshaveamoreelevatedMnenrich-mentontheexposedsurfacesthatindicatesathickerdesertvarnishandthereforelongerresidencetimeinthedesert.

Withacombinedstudyoftheweatheringgradeobservedinthinsection,fastmeasurementbyhandheldXRFofSroncutsurfacesandthedegreeofMnenrichmentonexposedsurfacesitshouldbepossibletoestimateapproximatetheterrestrialagesofOmanimeteorites.

REFERENCESAl-Kathiri,A.,HofmannB.A.,JullA.J.T.,andGnosE.2005:WeatheringofmeteoritesfromOman:Correlationofchemical/

mineralogicalweatheringproxieswith14Cterrestrialagesandtheinfluenceofsoilchemistry,Meteoritics&PlanetaryScience,40,1215-1239.

Gnos,E.,EggimannM.R.,Al-KathiriA.andHofmannB.A.2006:TheJaH091strewnfield,Meteoritics&PlanetaryScience41Suppl.,A64

Gnos,E.,LorenzettiS.R.,EugsterO.,JullA.J.T.,HofmannB.A.,Al-KathiriAandEggimannM.R.2009:TheJiddatalHarasis073strewnfield,SultanateofOman,Meteoritics&PlanetaryScience44,Nr3,375-387

Jull, T. 2006: Terrestrial Ages ofMeteorites. InMeteorites and the Early Solar System II (eds.D. S. Lauretta andH. Y.McSween),pp.889-905.UniversityofArizonaPress,Tucson.

Wasson,J.T.&KallemeynG.W.1988:Compositionsofchondrites,Phil.Trans.R.Soc.Lond.A325,535-544

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ion 4. Open Cryosphere session

M. Hoelzle, A. Bauder, B. Krummenacher, C. Lambiel, M. Lüthi, M. Phillips, J. Schweizer,

M. Schwikowski

Swiss Snow, Ice and Permafrost Society

4.1 DalbanCanassyP.,FunkM.:FlowdynamicsofthesteeppartofTriftgletscher(Switzerland)

4.2 DelaloyeR.,HauckC.,HilbichC.,LambielC.,MorardS.,ScapozzaC.:ElectricalResistivityTomographyMonitoringofpermafrostwithinthePERMOSnetwork

4.3 FaillettazJ.,FunkM.,SornetteD.:Icequakesasprecursorsoficeavalanches

4.4 FarinottiD.,HussM.,BauderA.,FunkM.:HowmuchiceisstoredbytheSwissglaciers?

4.5 Groot Zwaaftink C., Cagnati A., Crepaz A., Fierz C., Lehning M., Valt M.: Surface snow modeling at Dome C,Antarctica

4.6 HauckC.,HoelzleM.,HussM.,SalzmannN.,ScherlerM.,SchneiderS.:Integrativecryosphericresearch-anexampleintheSwissAlps

4.7 HussM.,BauderA.,FunkM.:Largescatterandmultidecadalfluctuationsinthe20thcenturymasslossof30Swissglaciers

4.8 HussM.:MassbalancemonitoringonPizolgletscher

4.9 LeBrisR.,BerthierE.,MabileauL.,TestutL.,RémyF.:IcewastageontheKerguelenIslands(49°S,69°E)between1963and2006.

4.10 MittererC.,MottR.,SchirmerM.,SchweizerJ.:Observationandanalysisoftwowet-snowavalanchecycles

4.11 ReiwgerI.,ErnstR.,SchweizerJ.,DualJ.:Shearexperimentswithsnowsamples

4.12 RiesenP.,HutterK.,FunkM.:Aviscoelasticconstitutiverelationdescribingprimaryandsecondarycreepandsolidelasticbehaviourofice

4.13 RingsJ.,HauckC.,HilbichC.:CouplingofERTandthermalmodellingtomonitorpermafrostwithoutboreholes

4.14 RyserC.,LüthiM.,BlindowN.,SuckroS.:ThepolythermalstructureofGrenzgletscher(SwissAlps)

4.15 SchaefliB.,HussM.:Simulationofhighmountainousdischarge:howmuchinformationdoweneed?

4.16 SchneiderS.,ScherlerM.:Impactofsnowmeltonzerocurtainandthawlayerdepthfordifferentsubsurfacetextures.Fieldandmodeling-basedstudiesattheMurtél-Chasteletsarea.

4.17 SchneiderT.,Katona-SerneelsI.:UsingXPDfordeterminingphysicalrockparametersofpermafrostmaterials

4.18 SteinkoglerW.,FierzC.,LehningM.,ObleitnerF.:AsystematicapproachtoquantifytheperformanceofSNOWPACK

4.19 StummD.,FitzsimonsS.J.,CullenN.J.,HoelzleM.,MachguthH.,AndersonB.MackintoshA.:MassbalanceofBrewsterGlacier,NewZealand,modelledoverthreedecades

4.20 ThevenonF.,AnselmettiF.S.,BernasconiS.M.,SchwikowskiM.:NaturalandanthropogenicprimaryaerosolsrecordfromanAlpineicecore(ColleGnifetti,SwissAlps).

4.21 UsselmannS.,HussM.,BauderA:Impactsofclimatechangeon22south-easternSwissglaciersfrom1900until2100

4.22 VieliA., FaezehM.N.:Understanding rapiddynamic changesofmarineGreenlandoutletglaciers fromnumericalmodeling

4.23 WerderM.,BauderA.,KeusenH.-R.,FunkM.:HazardassessmentinvestigationsinconnectionwiththeformationofalakeonthetongueoftheUntererGrindelwaldgletscher,BerneseAlps,Switzerland

4.24 WirzV.,SchirmerM.,LehningM.:Analysisoftemporalandspatialsnowdepthchangesinasteeprock

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Flow dynamics of the steep part of Triftgletscher (Switzerland)

DalbanCanassyPierre1,FunkMartin1

1 Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, CH-8092 Zurich, Switzerland (dalban@vaw.baug.ethz.ch)

Severalstudiesonhangingglaciershavebeentriedtohighlihtpossibleprecursorsbeforebreakoffs.Ifsatisfactoryresultshavebeenobtainedoncoldglaciers,itseemsthatbreakoffmechanismsaredifferentforthosewhicharetemperate,suchastheTriftgletscher,Switzerland(Gadmertal,BerneseAlps).

Duetothedisapearanceofahugeamountoficeinitslowerpartduringthelastdecades,thesteeppartofTriftgletscherwasdestabilized,andapro-glaciallakeappeared.Studiesshowedthatareleaseofanicemasswithmorethanonemillionm3couldcreateawavetriggeringafloodinthedownglaciervalley(Gadmertal).

To improve our understanding about ice break offs of temperate hanging glaciers, we have monitored the ice fall ofTriftgletscherusingdifferentways:Twoautomaticcameraswithatriggertimeeverythreehours,permittoperformthecomputationofthesurfacemotions,andthreeseismicsensors,whichpermittodetectandlocateseismiceventsassociatedwithiceqakes.

Theaimistocombineseismicandphotogrammetricresultsandcorrelatetheseismicactivitywithchangesintheobservedicesurfacemotions,inordertoforeseepossiblebreakoffs.

Firstresultsshowedthattimeperiodscharacterizedbythehighestsurfacevelocitiesalsohavethebiggestamountofseis-micevents.Thusthereseemstobearelationshipbetweendisplacementsinthesteeppartandseismicactivity,andthatseismicitycanbeusedasaforecasttool.Wealsonoticedthatthereweremoreeventsduringnightthanduringdaytime.Thisindicatesthatbasaldrainageactivityplaysanimportantroleintheicemotions.Welocatedeventsindifferentpartsoftheseracfall:cracksduetocrevassesopeningnearthesurface,andyetunknowneventsinthelowerpartbecauseoffallingoficeblocks.Thenextstepistodetectandlocateeventsfromstickandslipmotion,whichcouldcharacterizeprecursormotionstobreakoffs,andtodoavalidationbyusingtheterrestrialphotogrammetry.

Newsresultsaboutstickandslipmotioncharacterizationandphotogrammetricresultswillbepresented.

4.2

Electrical Resistivity Tomography Monitoring of permafrost within the PERMOS network

DelaloyeReynald1,HauckChristian1,HilbichChristin2,LambielChristophe3,MorardSebastien1,ScapozzaCristian3

1Department of Geosciences, Geography Unit, University of Fribourg, Chemin du Musée 4, 1700 Fribourg 2Glaciology, Geomorphodynamics & Geochronology, Physical Geography Division, Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, and Department of Geography, University of Jena, Germany (chilbich@geo.uzh.ch)3Faculté des géosciences et de l'environnement, Institut de Géographie, IGUL Quartier UNIL-Dorigny, Bâtiment Anthropole, 1015 Lausanne

ThePERMOSnetwork(PermafrostMonitoringSwitzerland)startedin2000andaimsatalong-termobservationofmountainpermafrost.Itcurrentlycomprisesmorethan20siteswherethethermalevolutionofthegroundand/orthegroundsurfaceismonitored.Besidesthesurfaceandsubsurfacetemperaturestheicecontentofthefrozengroundisnotonlyakeyparam-etercontrollingslopestabilityinperiglacialenvironmentsbutalsoanimportantinputparameterforpermafrostmodels.

Addressingthenecessityforamethodtomonitorthelong-termevolutionofthegroundicecontentinmountainpermafrostin the context of globalwarming, an Electrical Resistivity TomographyMonitoring (ERTM)networkwas initiated in theframeworkofPERMOSin2005.Incontrasttosinglegeophysicalsurveystheso-calledtime-lapseapproachofrepeatedmeas-urementsservestoovercomethecommonproblemoftheoftenambiguousinterpretationofabsoluteresistivityvalues.TheERTMapproachisbasedontheassumption,thattemporalchangesinthemeasuredelectricalresistivityprovideinformationonchangesinthesubsurfaceiceandwatercontent.

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FollowingapilotstudyontheSchilthorncrest,runningsince1999,anetworkoffourpermanentgeoelectricprofileswasestablishedin2005/2006atthreefurthersites(Murtèlrockglacier,Stockhornrockplateau,Lapirestalusslope)toevaluatethepotentialofpermafrostmonitoringbyrepeatedgeoelectricalmeasurements.BasedonthegoodresultsERTMisnowanoperationalelementofthePERMOSprogrammeandanumberofnewpermanentprofileswasinstalledduringthelastyears.Thenetworknowcomprises14permanentERTMprofilesat10 sites inSwitzerland, includingbedrock sites (Schilthorn,Stockhorn), rock glaciers (Murtèl, Gianda Grischa, Rechy), talus slopes (Lapires, Les Attelas, Dreveneuse, Creux du Van,Arolla),andanice-coredmoraine(Gentianes).

FirstresultsofthisuniquenetworkindicateahugepotentialoftheERTMapproachtodetectandcharacteriseclimatein-ducedgroundicedegradation.Theobserved2-dimensionalresistivitychangesrevealspatiallymoredetailedinformationthan1Dboreholetemperaturesandcontributetoanincreasedunderstandingoftheresponseofdifferentpermafrostland-formstoclimatechange.

4.3

Icequakes as precursors of ice avalanches

JéromeFaillettaz1,MartinFunk1&DidierSornette2,3

1 VAW, ETH Zürich, Laboratory of Hydraulics, Hydrology and Glaciology, Switzerland (faillettaz@vaw.baug.ethz.ch)2Department of Management, Technology and Economics, ETH Zürich3Department of Earth Sciences, ETH Zürich

AhangingglacierattheeastfaceofWeisshornbrokeoffin2005.Wewereabletomonitorandmeasuresurfacemotionandicequakeactivityfor21daysuptothreedayspriortothebreak-off.

Resultsarepresentedfromtheanalysisofseismicwavesgeneratedbytheglacierduringtherupturematurationprocess.Threetypesofprecursorysignalsoftheimminentcatastrophicrupturewereidentified:

anincreasingseismicactivitywithintheglacierachangeinthesize-frequencydistributionoficequakeenergy,andalog-periodicoscillatingbehavioursuperimposedonpowerlawaccelerationoftheinverseofwaitingtimebetweentwoicequakes.

Theanalysisoftheseismicactivitygaveindicationsoftheruptureprocessandledtotheidentificationoftworegimes:astableonewhereeventsareisolatedandnoncorrelatedwhichischaracteristicofdiffusedamage,andanunstableanddan-gerousoneinwhicheventsbecomesynchronizedandlargeicequakesaretriggered.

4.4

How much ice is stored by the Swiss glaciers?

DanielFarinotti1,MatthiasHuss1,2,AndreasBauder1&MartinFunk1

1Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH-Zurich, CH-8092 Zurich (farinotti@vaw.baug.ethz.ch)2 Department of Geosciences, University of Fribourg, CH-1700 Fribourg

Glaciersarecharacteristicfeaturesofmountainenvironmentsandplayanimportantroleinvariousaspects.Theyareakeyelementofthewatercycle,beingthusimportantforhydropowerproductionoragriculturalexploitation,andepitomizethe”untouchedenvironment”,beingpreciousfortourismindustry.Withtheongoingclimatewarming,theretreatofmountainglaciersisofmajorconcernandstudiesassessingfutureglacierchangesandrelatedimpactsrecentlyreceivedincreasinginterest.Suchpredictionsnecessarilyneedthepresenticevolumeasinitialconditionandfortransientmodelling,theicethicknessdistributionhastobeknown.

i)ii)iii)

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nRecently,Farinottietal.(2009a)developedamethodbasedonmassconservationandprinciplesoftheiceflowdynamicsforinferringtheicethicknessdistributionofaglacierfromtheinversionofthesurfacetopography.Weappliedthemethodto62glaciersintheSwissAlps,includingallicemasseslargerthan3km2insurfacearea,usingdirecticethicknessmeasure-mentstoconstrainthemodelparameters.Theresultingsetoficevolumeswerereferencedtotheyear1999bymeansofatimeseriesofglaciermassbalance(Farinottietal.,2009b,Hussetal.,2008)andusedtocalibrateavolume-areascalingrela-tion(Bahretal.,1997).TheobtainedrelationwasthenappliedtotheglacierscontainedintheSwissGlacierInventory2000(Paul,2007)inordertoestimatethetotalglaciericevolumeintheSwissAlps.

In1999,theglacierizedareaintheSwissAlpswas1063±10km2,with67%coveredbyglacierslargerthan3km2.FortheSwissAlps,weinferatotalglaciericevolumeof74±9km3(Farinottietal.,2009b).Nearlyonequarterofthisvolumeisstoredinthe hydrological basin of the Massa river, which comprises the three large glaciers Grosser Aletschgletscher,MittelaletschgletscherandOberaletschgletscher(Fig.1).Accordingtothetimeseriesofglaciermassbalance,theicevolumeintheSwissAlpsdecreasedby12%between1999and2008.Theextraordinarilywarmsummerof2003causedaicevolumelossofabout3.5%.

Figure1.InferredicethicknessdistributioninthehydrologicalbasinoftheMassariver.Availableradio-echosoundingprofilesareshown.

Hatchedareasareanalysedusingascalingrelation(FiguretakenfromFarinottietal.,2009b).

REFERENCESBahr,D.B.,Meier,M.F.andPeckham,S.D.,1997.Thephysicalbasisofglaciervolume–areascaling. JournalofGeophysical

Research102(B9),20355-20362.Farinotti,D.,Huss,M.,Bauder,A.,Funk,M.andTruffer,M.,2009a,Amethodtoestimatetheicevolumeandice-thickness

distributionofalpineglaciers.JournalofGlaciology,55(191),422-430.Farinotti,D.,Huss,M.,Bauder,A.andFunk,M.,2009b.AnestimateoftheglaciericevolumeintheSwissAlps.Globaland

PlanetaryChange,68,225-231.Huss,M.,Bauder,A.,Funk,M.andHock,R.,2008.DeterminationoftheseasonalmassbalanceoffourAlpineglacierssince

1865.JournalofGeophysicalResearch,113,F01015.Paul, F., 2007.ThenewSwissGlacier Inventory2000 -ApplicationofRemoteSensingandGIS. SchriftenreihePhysische

Geographie,Vol.52,UniversityofZurich.210pp.

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Surface snow modeling at Dome C, Antarctica

GrootZwaaftinkChristine1,CagnatiAnselmo2,CrepazAndrea2,FierzCharles1,LehningMichael1,ValtMauro2

1WSLInstituteforSnowandAvalancheResearchSLF,Davos,Switzerland2ARPAV CVA, Arabba di Livinallongo, Italy

ModelingeffectivelysurfacesnowcompactioninAntarcticaisofgreatinterestforabetterunderstandingofexchangeproc-essesbetweenthesnowsurfaceandtheatmosphereaswellastheirrelevancetosurfacemassbalance.AtDomeC,wemeas-uredwaterequivalentofsolidprecipitationcollectedabout0.8mabovethesnowsurface.Thedensityofthiscollectedsnowvariesroughlyfrom50to300kgm-3withameanaround80kgm-3.Ontheotherhand,themeasureddensityoverthetop10cmofthesnowcoverbeingabout300kgm-3,thislayerroughlyrepresentsthemeanyearlyaccumulationatDomeC,forwhichdetailedsnowprofiles,continuousrecordsofsnowtemperatures,andatwoyearmeteorologicaldatasetareavailable.Therearesomeobservationsofdriftingsnoweffectsandweexpectwindtoplayamajorroleinthisdensificationprocess.

Extensive qualitative descriptions of the snow deposition process exist in literature but no detailed quantitative study.AdjustingitssettingstotheextremeAntarcticclimate,weuseSNOWPACK,aflexible,modularsnowcovermodeltosimulatesnowcoverevolution.Theinfluenceofthewindonrapiddensificationisparameterizedbymeansofaneventdrivensnowdeposition.Thisresultsinamorerealisticsnowcoverwithapronouncedstratigraphy,evidentinsnowdensityandgrainsizes.

Othermechanismswhichwetrytoincludearetheinfluenceofwatervapordepositionandsublimationatthesurface,forexample.

Wewilldiscussimplicationsfromourresultsforfuturestudieswithrespecttobothmodelingandinsitumeasurementsrelatingtothisveryimportantprocess.

4.6

Integrative cryospheric research - an example in the Swiss Alps

HauckChristian,HoelzleMartin,HussMatthias,SalzmannNadine,ScherlerMartin,SchneiderSina

Alpine Cryosphere and Geomorphology (ACAG), Department of Geosciences, University of Fribourg, Chemin du Musée 4, CH-1700 Fribourg

Asclimateischangingandthediscussiononimpactsandadaptationareemergingrapidlyinthescientificandpoliticaldialogue,itbecomesevenmorecriticaltoobserve,analyseandunderstandimportantcomponentsoftheclimatesysteminanintegratedmanner.Observationsaretheindispensablepreconditiontoimproveprocessunderstanding.Moreover,onlywithareliableandconsistentdatabaseline,modelscanbeverifiedandtheuncertaintyinprojectionsoffuturechangescanbeassessed.

Thehigh-mountaincryosphereisparticularlysensitivetochangesintheatmosphericconditionswithseveralfeedbackme-chanismsonvariousspatialandtemporalscales.Atthesametime,alsothecryosphericcomponents,snow,iceandperma-frost,interrelatewhichleadstonon-linearresponsestoclimatechange.Atypicalexampleisthedifferingeffectofthesnowcoverforglaciermassbalancevariabilityandgroundisolationoverpermafrostoccurrences.Itisthereforecriticaltoadvan-ceintegratedmeasurementandanalysisconceptsforallcryosphericcomponentsofhigh-mountainenvironments.

Therecentlyformednewresearchgroup ‘AlpineCryosphereandGeomorphology (ACAG)’attheUniversityofFribourgisaimingatactivelyadvancingintegratedinvestigationinhigh-mountainenvironments.Thearea‘Stockhorn-Findelgletscher’nearZermatt,Valais,hasbeenchosentobecomea‘posterchild’ofintegratedcryosphericresearchwherevariousmeasure-mentandmodellingapproachesareapplied.Measurementsincludeallcomponentsoftheenergybalance,spatialdistribu-tionofsnowaccumulation,glaciermassbalance,permafrostgroundtemperaturesdownto100m,geophysicalmonitoringoficeandwatercontentandgroundsurfacetemperatures(e.g.Gruberetal.2004,Machguthetal.2006,Hilbichetal.2008).Inaddition,newmodelapproachestodeterminetheresponseofglaciermassbalance(Findelgletscher),activelayerdepth(permafrostStockhorn)andevolutionofgroundicecontentareusedtoanalysetheimpactofclimatechangeonglaciersandpermafrostandtheirrespectivedifferences(e.g.Haucketal.2008).

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Figure1.FindelgletscherandStockhornpermafrostmonitoringsite.Firstresultsofthedistributedsnowaccumulationmeasurementsin

April2009areshown.Crossesindicatesnowprobings,theinferreddistributionofthesnowwaterequivalentisshowningreyscales.

REFERENCESGruber, S., L.King,T.Kohl, T.Herz,W.Haeberli,&M.Hoelzle. 2004. Interpretationofgeothermalprofilesperturbedby

topography:TheAlpinepermafrostboreholes at StockhornPlateau, Switzerland. PermafrostPeriglacial Processes, 15,349-357.

Hauck,C.,Bach,M.&Hilbich,C.2008.A4-phasemodeltoquantifysubsurfaceiceandwatercontentinpermafrostregionsbasedongeophysicaldatasets.Proceedingsofthe9thInternationalConferenceonPermafrost,Fairbanks,Alaska,1,675-680.

Hilbich,C.,Hauck,C.,Delaloye, R.&Hoelzle,M. 2008.A geoelectricmonitoringnetwork and resistivity-temperaturerelationshipsofdifferentmountainpermafrostsitesintheSwissAlps.ProceedingsNinthInternationalConferenceonPermafrost,Fairbanks,Vol.1,KaneD.L.andHinkelK.M. (eds), InstituteofNorthernEngineering,UniversityofAlaskaFairbanks,699-704.

Machguth,H., Eisen,O., Paul, F.&Hoelzle,M., 2006. Strong spatial variability of snow accumulation observedwithhelicopter-borne GPR on two adjacent Alpine glaciers. Geophysical Research Letters, 33 (L13503): doi:10.1029/2006GL026576

4.7

Large scatter and multidecadal fluctuations in the 20th century mass loss of 30 Swiss glaciers

HussMatthias1,2,BauderAndreas2&FunkMartin2

1 Department of Geosciences, University of Fribourg, 1700 Fribourg, Switzerland (matthias.huss@unifr.ch)2 Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, 8092 Zürich, Switzerland

Theongoingretreatofmountainglaciersstronglyimpactsonthehydrologicalcycle,mightcauseeconomiclossesinalpineregionsandisexpectedtodominateeustaticsealevelriseoverthenextcentury.Long-termtimeseriesofglaciermassba-lancerepresentakey toprojecting futureglacierchangesandunderstandingtheglacier-climate linkage.However,massbalanceismeasuredononlyafewglaciers,andtherecordstypicallyareonlysomedecadeslong.

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ion Here,wepresentthirtynewtimeseriesofglaciersurfacemassbalance,accumulationandmeltoverthepast100yearsin

theSwissAlps.Thedatasetincludesdifferentglaciersizes,exposuresandregions,andthusconstitutesthefirstlong-termmassbalancetimeseriesbeingrepresentativeonamountainrangescale.Ourresultsarebasedonacomprehensivesetoffielddataandmodelling.Foreachglacier,upto10high-accuracydigitalelevationmodels(DEMs)wereestablishedprovidingicevolumechangesinsubdecadaltosemicentennialperiods.Inaddition,morethan8000directobservationsofannualmassbalanceandwinteraccumulationareavailable.Thisdatabasewasusedtoconstrainadistributedtemperature-indexmodel(Hock,1999;Hussetal.,2008)drivenbydailyairtemperatureandprecipitationfortheperiod1908-2008.

Allglaciersshowconsiderablemassloss,butratesdifferstronglybetweenindividualglaciers(Fig.1).100-yearcumulativemassbalancevariesbetween–11mwaterequivalent(Allalingletscher)and–65mw.e.(Griesgletscher).Thesestrongdiffe-rencesintheresponseofglaciermassbalancetochangesinclimateforcingareattributedtoaninteractionofseveralcom-plexprocesses.Largeandflatglacierstendtohavemorenegativemassbalanceduetotheirlongreactiontime.Positiveandnegativealbedofeed-backmechanisms,aswellaschangingwinterprecipitation,variableonsmallerspatialscalesthanairtemperatures,mightalsoexplainsomeofthedifferences.

Masslossisparticularlyrapidinthe1940sandlate1980stopresent,whileshortperiodsofmassgainoccurredinthe1910sandlate1970s(Fig.1).Thisindicatesthatglaciermasslossoverthe20thcenturywasnotlinear,butexhibitsimportantlong-termvariations.WefindoscillationsintherateofglaciermasslossintheSwissAlpswithaperiodof65years.GlaciermassbalanceissignificantlyanticorrelatedtotheAtlanticMultidecadalOscillation(AMO)indexwhichreferstoanomaliesintheseasurfacetemperatureintheNorthAtlantic.WethusproposealinkbetweenAtlanticOceancirculationandAlpineglaciermassloss.

Figure1.Timeseriesofcumulativemeanspecificannualmassbalanceof30Swissglaciersinthe20thcentury.Blackdotsindicatethe

datesofDEMs.Thesolidlinerepresentsthearithmetic30-glacieraverage.Glaciernamesandnumbersarearrangedaccordingtodescen-

dingglaciersize.Thedash-dottedlineshowsthecumulativetotalvolumechangeofthe30glaciers(right-handsideaxis).Twoshortperi-

odswithmassgainandtwoperiodswithfastmasslossaremarked.

REFERENCESHock,R.,1999.Adistributedtemperature-indexice-andsnowmeltmodelincludingpotentialdirectsolarradiation.Journal

ofGlaciology,45,101–111.Huss,M.,Bauder,A.,Funk,M.&Hock,R.,2008.DeterminationoftheseasonalmassbalanceoffourAlpineglacierssince

1865.JournalofGeophysicalResearch,113,F01015.

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Mass balance monitoring on Pizolgletscher

HussMatthias1,2

1 Department of Geosciences, University of Fribourg, 1700 Fribourg, Switzerland (matthias.huss@unifr.ch)2 Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, 8092 Zürich, Switzerland

Verysmallglaciersarerarelysubjectofglaciologicalstudies.AlthoughtheseglaciersonlycoveralimitedfractionoftheglacierizedareaintheAlps,theirnumberisconsiderable.Accordingtoglacierinventorydata,82%oftheSwissglaciersaresmaller than 0.5 km2. So far, the mass balance of glaciers in this important size class was never investigated inSwitzerland.

In2006anewmassbalancemonitoringprogramontheverysmallPizolgletscher,north-easternSwissAlps,wasstarted.Pizolgletscherhasanareaofcurrently0.08km2andisarelativelysteep,north-exposedcirqueglacier(Fig.1).Themonitoringprogramconsistsoftwofieldsurveys,oneinAprilandoneinSeptember,andwillbecontinuedoverthenextyears.Duringthewintersurveythespatialdistributionofsnowaccumulationisdeterminedbyupto100snowprobingsonadensenet-workandsnowdensitymeasurementsinasnowpit.Threestakesdrilledintotheiceprovideinformationabouttheannualmassbalance(Fig1a).Inaddition,thechangesinglacierareaandicevolumeareknowninsubdecadalintervalsfromsevenphotogrammetricsurveyssince1968providinghigh-accuracydigitalelevationmodels.

Basedontheseasonalin-situmeasurementsglacier-widemassbalanceisdeterminedusinganovelmethod.Adistributedmassbalancemodelwithdailytimestepsistunedtomatchboththemeasuredsnowwaterequivalentinspringandtheannualmassbalanceatthestakes(Huss,2009).Theobservedaccumulationdistributionisusedtoconstrainthemodelinspace.Thismethodallowsanoptimalexploitationofthefielddata,thedeterminationofmassbalanceoverfixedtimepe-riodsand,thus,thecomparisonofdifferentyears.

InthetwofirstyearsofthesurveyPizolgletscherwassubjectedtostrongmassloss.Theannualmassbalancein2006/2007was–1.60mwaterequivalent(w.e.)andin2007/2008–0.83mw.e.Thewinteraccumulationwaslowin2007withanearlyonsetofthemeltingseason.InApril2008and2009,however,averagesnowdepthsofalmost5metresweremeasured,coun-teractingthehighairtemperaturesofthefollowingsummer.ThespatialpatternofsnowdepositiononPizolgletscherishighlyvariableandimportantlydeterminedbywind(Fig.1b).Consequently,glacieradvanceisduetoanappositionoffirninfrontoftheglaciertongue,andisnotrelatedtoadynamicreactionoficeflow.Pizolgletschercan,thus,changeitsareaandlengthrapidly,whichisillustratedbythelengthchangemeasurementscarriedoutsincethelate19thcentury.

Figure1.(a)FrontviewandmapofPizolgletscher.Thepositionofthemassbalancestakesisshown.(b)OrthophotographofPizolgletschertakeninSeptember1973.Linesindicateglacierextentin1968,1973,1997and2006.Theinhomogeneousdis-tributionofsnowiswellvisible.Theinsetshowsthechangeinglacierarea(dA)andvolume(dV)relativetotheyear1968.

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ion Between1968and2006Pizolgletscherhaslostmorethan60%ofitsareaandvolume,mostofthedecreasetakingplaceover

thelasttwodecades(insetinFig.1b).Extrapolatingthislossintothefutureis,however,unreliable,astheglacierwillretre-atbydegreesintoamoreprotectedcirquewithhighaccumulationrates,seekingforanewequilibrium.Basedontheobser-vedicevolumechanges,theseasonalmassbalanceoverthelast40yearswasreconstructedaccordingtoHussetal.(2008).The cumulativemass balance is –17mw.e.,which is consistentwith othermass balance records in the SwissAlps (e.g.Silvrettagletscher).Ashortperiodofmoderatemassgains inthe late1970s is followedbystrongmass loss, inparticularsince2003.

ThefirstresultsofthenewmassbalancemonitoringprogramonPizolgletscherarepromisingandhaverevealedinterestinginsightsintotheresponseofsmallglacierstoclimatewarming,inparticulartheirhighsensitivitytoaccumulationchangesandtheimportanceofthespatialdistributionofsnowdeposition.

REFERENCESHuss,M.,Bauder,A.,Funk,M.&Hock,R.,2008.DeterminationoftheseasonalmassbalanceoffourAlpineglacierssince

1865.JournalofGeophysicalResearch,113,F01015.Huss,M,2009.PastandFutureChangesinGlacierMassBalance,Chap.A.1.DissertationNo.18230,ETHZürich,218pp.

4.9

Ice wastage on the Kerguelen Islands (49°S, 69°E) between 1963 and 2006

RaymondLeBris2,EtienneBerthier1,LaureMabileau1,LaurentTestut3,andFrédériqueRémy1

1LEGOS, CNRS, Toulouse, France.2Department of Geography, University of Zurich, Zurich, Switzerland. (rlebris@geo.uzh.ch)3LEGOS, Université de Toulouse, Toulouse, France.

TheglaciersandicecapslocatedaroundtheAntarcticandGreenlandicesheetscontainasignificantfractionofthelandiceonEarth(Dyurgerov&Meier.2005).Difficulttoaccess,theirresponsetoclimaticfluctuationsandtheirrecentevolutionarepoorlyknown(Gordonetal.2008).Becausethebehavioroftheseicemassesalsoconstitutesagenuineclimaticindicator,theobjectiveofthisstudyistoassessthechangesoftheextentandvolumeofglaciersandicecapsonKerguelenIslanddur-ingthelastfortyyears(Berthieretal.2009).ThisstudyisalsoacontributiontotheGLIMSinitiative(Raupetal.2007)

Basedonarchiveddata (e.g. IGNmappublishedin1967,glaciologicalcampaignscarriedout inthe1970s)andonrecentsatellitedata(Landsat,SPOT,SRTM,ICESat),wedefinesuccessiveoutlinesoftheprincipaloutletglacierstomeasurethepaceoftheretreatoftheCookIceCap.InordertounderstandtheresponseoftheIceCaptoclimaticforcing,wealsoanalyzedtheclimaticdatarecordedbytheMétéoFrancestationinPortauxFrançais.

Theresultsrevealthatallglaciershaveretreatedsince1965althoughastrongvariabilityexistsfromoneoutletglaciertoanother.OnestrikingresultistheEast/Westasymmetryoftheglacierretreat:west-flowingglaciershavelost11.4%oftheirareawhileeast-flowingglacierlost28.2%.ThedramaticretreatontheeasternsideisillustratedbytheretreatofExplorer’sGlacierfrontby3150m+/-162msince1965oranaverageof75m/yr.Furthermore,theAmpèreGlacierthinnedonaverageby125m+/-16minthefrontalarea,about-4.8m/yr.(cf.alsoVallon1977).Locally,themeanthinningrateduringthelast40yearsreachedasmuchas10m/yr.

Intotal,theicecaplost20%ofitssurfaceareaoveraperiodofthirty-eightyears(1965-2003).TheCookIceCapisinrecessionsincenearlyonecenturyandthistrendacceleratedsincetheyears1960-70(Frenotetal.1993).Theanalysisofmostrecentsatelliteimages(fromtheyears2003to2007)showsthattheretreatcontinuestodaywiththesamespeedorevenslightlyfaster.

Theicecapisthusfarfromitsstateofbalance. If thecurrentclimaticconditionsprevail (hightemperaturesandarela-tivelylowlevelofprecipitation)oriftheyareevenamplifiedinthefuture,itmightbepossiblethattheicecapwilltotallydisappear.

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Figure1.TopographyoftheKerguelenIslands.Thefourmainglacierizedregionsandthebasestation(Portaux-Français)arealsoindicated.

ThesmallglobeidentifiesthelocationoftheislandintheSouthIndianOcean.

Figure2.East-westasymmetryoftheCookIceCapshrinkage.

Thedarkgrayrepresentsice-coveredareasthatdisappearedbetween1963and2001.

REFERENCESBerthier, E., Y. Arnaud,C. Vincent, and F. Remy (2006), Biases of SRTM inhigh-mountain areas: Implications for the

monitoringofglaciervolumechanges,Geophys.Res.Lett.,33,L08502,doi:10.1029/2006GL025862.Dyurgerov,M.B.,andM.F.Meier(2005),GlaciersandtheChangingEarthSystem:A2004Snapshot,117pp.,Inst.ofArctic

andAlp.Res.,Univ.ofColo.,Boulder.Frenot, Y., J.-C.Gloaguen,G. Picot, J. Bougère, andD. Benjamin (1993),Azorella selagoHook.used to estimate glacier

fluctuationsandclimatichistoryintheKerguelenIslandsoverthelasttwocenturies,Oecologia,95,140–144.Gordon, J. E.,V.M.Haynes, andA.Hubbard (2008),Recentglacier changesandclimate trendsonSouthGeorgia,Global

Planet.Change,60(1–2),72–84,doi:10.1016/j.gloplacha.2006.07.037.Raup,B.,etal.(2007),RemotesensingandGIStechnologyintheGlobalLandIceMeasurementsfromSpace(GLIMS)project,

Comput.Geosci.,33(1),104–125,doi:10.1016/j.cageo.2006.05.015.Vallon,M. (1977a), Bilandemasse et fluctuations récentes du glacierAmpère (Iles Kerguelen, TAAF), Z.Gletscherkd.

Glazialgeol.,13,55–85.

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Observation and analysis of two wet-snow avalanche cycles

ChristophMitterer,RebeccaMott,MichaelSchirmer,JürgSchweizer

WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, CH-7260 Davos Dorf (mitterer@slf.ch)

Theformationofwet-snowavalanchesaswellasthesnowpackprocessesleadingtowet-snowinstabilitiesarepoorlyunder-stood.Forecastingwet-snowavalanchesisagreatchallengeandposesgreatdifficultiesforlocalauthorities.Betterknowl-edgeabouttheprocessesleadingtowet-snowinstabilitiesisthereforeveryimportant.Duringthewintersof2007-2008and2008-2009twodistinctwet-snowavalanchecyclesoccurredinthesurroundingsofDavos,Switzerland.Weanalyzedmete-orologicaldata,in-situsnowpackinformationandmappedavalancheextent.Inaddition,thesnowcovermodelSNOWPACKwasusedtofillthegapwheresnowpackdata,suchasvolumetricwaterorsnowtemperature,werenotavailable.Snowpackinformationfordifferentelevationbandsweremodelledbyusingaconstantlapse-rateforairtemperatureandincominglongwaveradiation.Theanalysisfocusedonthecausesofinstability:loadingand/orweakeningduetowaterinfiltration.The full energy balance was calculated usingmeteorological data and extrapolated to the investigation area using themodelALPINE3D.Bothavalanchecyclesoccurredinashortperiodoftime.The2007-2008avalanchecyclewascharacterizedbyshortperiodsofwarmingandadditionalloadingbysnowfallandinputofmeltwaterduetorain.Forthe2008-2009wet-snowavalanchecycle,ontheotherhand,distinctwarmingandsolarradiationwereprobablyresponsibleforahigherpro-ductionofmeltwater.Terrainparameterssuchasaspectandslopeanglecombinedwithliquidwaterinfiltrationpatternswerecrucialduringthesecondwet-snowavalanchecycle.Snowpackdatasuggestthatinthefirstyearsnowstratigraphyfavouredtheformationofweaklayers,whereasforthesecondyearsnowstratigraphymayhavefavouredagradualripeningofsnowpackleadingtoaweakeningofthebasallayers.

4.11

Shear experiments with snow samples

IngridReiweger1,RobertErnst1,JürgSchweizer1,JürgDual2

1 WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland (reiweger@slf.ch)2 Institute of Mechanical Systems, ETH Zürich, Switzerland

Naturaldry-snowslabavalanchesstartwithafailurewithinaweaksnowlayer.Inordertounderstandthemechanicalbe-haviourandthefailuremechanism,weperformedloadingexperimentswithhomogeneousandlayeredsnowsamplesundercontrolledconditionsinacoldlaboratory.Forsimulatingloadingconditionssimilartothenaturalsnowpack,wedesignedandbuiltanapparatuswhereasnowsamplecanbetiltedbya‘slopeangle’andisloadedviathegravitationalforce.Thedeformationwithin the snow samplewasmeasuredopticallywith a pattern recognition algorithm (PIV). Shortly beforemacroscopicfailure(breakingofthewholesample)weobservedaconcentrationofdeformation(softening)withintheweaklayer.Additionally,wemeasureacousticemissionsduringtheshearexperimentstoquantifythemicroscopicfailure(brea-kingofbonds) inthesnowsamplebeforethecompletefailure.Ourresultssupporttheassumptionthatthedominatingmechanismsforsnowdeformationarethecompetingprocessesofbreakingandsinteringofbondsbetweengrains.ResultsfromPIVclearlyshowedthatwhenalayeredsnowsamplewassubjectedtoaconstantslowloadingrate,thedeformationwasconcentratedwithintheweaklayer.Thishasoftenbeenassumedbuthasnotbeendocumentedsofar.Preliminaryre-sultsoftheacousticemissionmeasurementsofthehomogeneoussamplesindicatedthattheAEmayhintonthemicrome-chanicsduringdeformation.

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A viscoelastic constitutive relation describing primary and secondary creep and solid elastic behaviour of ice

RiesenPatrick1,HutterKolumban1,FunkMartin1

1Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie (VAW), ETH Zürich, CH-8092 Zürich

Theflowofglaciericeiswidelytreatedbyastress-strainrelationcommonlyreferredtoasGlen'sflowlaw.TheGlenflowlawisapureviscousrelation,henceacertainamountofstressimmediatelycorrespondstodeformation(i.e.strainrate),inde-pendentoftimeandpossiblerelaxation.Thisbehaviourisappropriateforstationary(secondary)creepofice.However,re-centdetailediceflowmeasurementsonGornergletscher,Switzerland,performedduringthedrainageofaglacierdammedlake,haveidentifiedparticularunexplainedflowchangeswheresignificantvariationsoccurwithinafewhourstoseveraldays.Itwassuggestedthatelasticeffectsmayplayaroleinsucharapidresponseofglacierice.Fromanengineeringpointofview,theloadsrequiredtoproducedisplacementsoftheicesimilartothoseobserved,isontheorderofseveral105Pa.Inthisrange,linearviscoelasticbehaviouroficemaybeinappropriateandonemustconsidernon-linearviscoelasticresponseoftheice.However,manyexperimentsandcreeptestsconductedinthepasthaveshownnon-stationary(primary)creeptobeeffectiveforapproximatedurationsofafewhourstoafewdays.Wethereforeconjecturethatprimarycreepplaysaroleinshort-timeglacierflowvariations.Totestourhypothesisandelucidatetheinfluenceofpossibleviscoelasticeffects,weconstructedaconstitutiverelationwhichisabletoreproduceprimaryandsecondarycreepaswellaselasticeffects.Amo-difiedRivlin-Eriksenfluidmodel,wherethestressisrelatedtobothstrainrateandstrainaccelerationsisusedtodescribeprimaryandsecondarycreepoftheice.Wecoupletheviscousfluidmodelwithanon-linearelasticKelvin-typestress-strainrelationtoenablethematerialtoexhibitelasticbehaviourofasolid.Theconstitutiverelationobeysthermodynamicrequire-ments.Thetransientresponseiniceflowisthusassignedtotheeffectsofviscoelasticrelaxationandprimarycreep.Thedecoupledformulationallowstostudythoseeffectsseparatelyorincombination.Somefirstnumericalresultsusingthefiniteelementmethodhavebeenobtainedfortwoglaciologicalbenchmarkproblemsof(i)flowinachanneland(ii)flowoveraninclinedslab.

4.13

Coupling of ERT and thermal modelling to monitor permafrost without boreholes

RingsJörg1,HauckChristian2,HilbichChristin3

1 ICG 4 Agrosphere, Forschungszentrum Jülich, Germany2 Alpine Cryosphere and Geomorphology (ACAG), Department of Geosciences, University of Fribourg, Chemin du Musée 4, CH-1700 Fribourg3 Glaciology, Geomorphodynamics & Geochronology, Department of Geography, University of Zurich, Winterthurerstr. 190, CH-8057 Zurich

Geophysicalmethods,andespeciallytheElectricalResistivityTomography(ERT)method,arebeingrecognisedasstandardtoolsforthedetectionandmonitoringofpermafrost,sincerecentadvancesindataacquisitionandprocessinghavemadetheirapplicationworthwhileeventhoughsomeefforthastobemadetoensuregooddataqualityandreliableinversionresults(Hilbichetal.2009).Inmanyscientificstudiesboreholetemperaturedataserveasgroundtruthforthegeophysicalresults,enablingathoroughandrigorousassessmentofthequalityoftheapproach.Furthermore,ERTyields2-and3-di-mensionaldataofthesubsurfaceandissensitivetotheunfrozenwaterandicecontent,whichiscomplementarytothe1-dimensionaltemperaturemeasurementsinboreholes.

Ontheotherhand,thenon-invasivenessofthegeophysicalsurveysandthecorrespondinglowcostsandminimaldistur-banceofthesystemtobemonitoredisusuallyseenasthemajoradvantageofgeophysicsasopposedtoboreholes.Forfutu-reautonomousandwidespreadmonitoringsystemsforpermafrost(similartothesnowandmeteostationnetworks),apu-relygeophysicalapproachisenvisaged.However,ERTmeasurestheelectricalresistivityofthesubsurface,whichhastoberelatedtoicecontentortemperature.Commonapproachesusepetrophysicalrelationships(suchasthewell-knownArchie'sLaw)torelatethemeasuredresistivitychangestosaturationandicecontentchangesortemperature(Haucketal.2008).Butwithoutgroundtruthdatafromboreholesorextensivelaboratorycalibrationusingsubsurfacematerial,theexactnatureofthesite-specificpetrophysicalrelationshipcannotbedetermined.

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ion Inthiscontribution,weintroduceafilteringapproachcombinedwithcoupledmodellingofthermalconductionandERT

topredictsubsurfacetemperaturesbasedonERTmonitoringdatawithouttheneedforboreholeorlaboratorydata.WeusesequentialBayesianfilteringorparticlefiltering(seee.g.Arulampalametal.2002),whichhastheadvantageofcontinuous-lyprovidingprobabilitydistributionsofstate(temperature)andparameters(e.g.thermalconductivity)whenevermeasure-mentsbecomeavailable.Aparticlefilterapproximatesthesedistributionsbyasetofdiscrete,weightedparticles.Initialstateandparameteraredrawnfrompriordistributionsandthermalconductionismodelledindependentlyforeachparticle.Themodelledchangeintemperatureistransferredtochangeinresistivitybyalinearrelation,andanERTforwardmodelisusedtosimulatethesystemresponse.Then,theparticlesareweightedaccordingtotheagreementbetweenmeasuredandmo-delledERTresponse.Are-samplingroutineisusedtoensurethat,overtime,theparticlesgravitatetowardstheposteriordistributionsofstateandparameter.

Totesttheapproach,modelledandobservedgroundtemperatureswerecomparedatthehigh-altitudepermafroststationonSchilthorn,BernerOberland/SwissAlps.FirstresultsusingautomatedERTmonitoringdatafromthePERMOS(PermafrostMonitoring Switzerland) network show a good performance during a 3-month period in spring and summer 2009.Improvementscanbeachievedbyusingmoresophisticatedthermalmodelsandbyiterativeprocedurestodeterminethe(verticallyvariable)materialpropertiesofthesubsurface,suchasporosityandthermalconductivity.

REFERENCESArulampalam,M.S.,Maskell,S.,Gordon,N.&Clappt,T.2002.Atutorialonparticlefiltersforonlinenonlinear/non-Gaussian

Bayesiantracking,IEEETransactionsonSignalProcessing,50,174-188.Hilbich,C.,Marescot,L.,Hauck,C.,Loke,M.H.&Mäusbacher,R.2009.ApplicabilityofERTmonitoringtocoarseblockyand

ice-richpermafrostlandforms.PermafrostandPeriglacialProcesses20(3),269-284.Hauck,C.,Bach,M.&Hilbich,C.2008.A4-phasemodeltoquantifysubsurfaceiceandwatercontentinpermafrostregionsbased

ongeophysicaldatasets.Proceedingsofthe9thInternationalConferenceonPermafrost,Fairbanks,Alaska,1,675-680.

4.14

The polythermal structure of Grenzgletscher (Swiss Alps)

ClaudiaRyser1,MartinLüthi1,NorbertBlindow2,SonjaSuckro2

1 Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie (VAW), ETH-Zürich, 8092 Zürich, Switzerland (ryser@vaw.baug.ethz.ch)2 Institut für Geophysik der Westfälischen Wilhelms- Universität Münster, 48149 Münster, Germany

Withacombinationofboreholemeasurementsandhelicopter-borneiceradar,thetemperaturedistributioninthelowerpartofthepolythermalGrenzgletscher(SwissAlps)wasinvestigated.Verticaltemperatureprofilesweremeasuredin12deepboreholes.ColdicewasfoundinacentralflowbandintheGrenzgletscherbranch,wherethecoldestice(-2.6°C)wasfoundin60-75mdepth.Thecoldiceoccupies80-90%oftheicethicknessof200-320m,andislaterallyconnedtoabandof+/-200mfromthecentralflowline.Theiceistemperateclosetothebedandtowardsthemargins.ComparisonoficeradarsoundingsacquiredwiththeUMAIRgeoradarwithboreholetemperaturesshowsthatlow-backscatterzonescoincidewithiceattem-peraturesmore than0.5Kbelow thepressuremelting temperature. The low-backscatter zonesare thusused tomap thedistributionofcoldiceonthewholelowerglacier.Thecoldiceadvectedfromtheaccumulationcausesazoneofpersistentsuperficialmeltwaterstreamsandlakes.

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Simulation of high mountainous discharge: how much information do we need?

Schaefli,Bettina1andHuss,Matthias2

1 Water Resources Section, Faculty of Civil Engineering and Geosciences, Delft University of Technology, 2600GA Delft, The Netherlands (b.schaefli@tudelft.nl)2 Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, 8092 Zurich. Now at: Alpine Cryosphere and Geomorphology, Department of Geosciences, University of Fribourg, 1700 Fribourg, Switzerland

Forthemanagementofwaterresources,thehydrologiccycleofhighmountainouscatchmentsisfrequentlysimulatedwithverysimpleprecipitation-dischargemodelsrepresentingthesnowaccumulationandablationbehaviorofaverycomplexenvironmentwith a set of lumped equations accounting only for altitudinal temperature andprecipitationdifferences.Thesemodelsaregenerallycalibratedsothatthemodelreproducesascloselyaspossibleaseriesofobserveddischargemea-surements.Thequestioninevitablyariseswhetherlongtermpredictionsofsuchacalibratedmodelareactuallyreliable,sinceknowingthatamodelperformswellforhistoricsituationsdoesbynomeansimplythatitwillperformwellforfuture,considerablymodifiedcatchmentconditions.Afirst,althoughnotsufficientsteptoanswerthisquestion,isinvestigatingwhetherwithsuchamodel,weare“gettingtherightanswersfortherightreasons”.Inglacierizedcatchments,thiswouldforexampleimplythataprecipitation-runoffmodelshouldnotjustmimicobserveddischargebutalsoreproducetheglaciermassbalance.

Inthisstudy,weshowhowmuchobservedinformationweneedtoreliablycalibrateahydrologicalmodelforahighmoun-tainous catchment. Based on glacio-hydrological data from theRhone glacier catchment,we analyzehowwell a simpleconceptualprecipitation-runoffmodel(GSM-SOCONT,Schaeflietal.,2005)canreproduceseasonalglaciermassbalancedataandinasecondstep,howmuchinformationisrequiredtoachieveareliablemodelcalibration.Here,wefocusontheques-tionwhetherobserveddischargeissufficientorwhetherweneedannualorevenseasonalglaciermassbalancedata.

Forthisparticularcatchment,adetailedreproductionofobservedseasonalbalancesrequiresamodificationoftheaccumu-lation and ablationmodule of GSM-SOCONT. Themodel only accounts for altitudinal differences of themeteorologicalconditionsande.g.notforwinddriftorexposition.Asourresultsshow,introducingseasonalaccumulationandablationparametersissufficienttoenablethissimplemodeltoreproduceobservedseasonalbalances (Fig.1)andannualnetbal-ances(Fig.2).Furthermore,ourresultssuggestthatcalibratingthehydrologicalmodelexclusivelyondischargecanleadtowrongrepresentationsof the intra-annualaccumulationandablationprocessesand, thus, toabias in longtermglaciermass balance simulations (Fig. 2). Adding only a few annual net balance observations considerably reduces this bias.Calibrating exclusively on annual net balance data can, in turn, lead towrong seasonalmass balance simulations (notshown).

Eveniftheseresultsarecasestudyspecific,ourconclusionsgivevaluablenewinsightsintothebenefitofdifferenttypesofobservationsforcalibratinghydrologicalmodelsinhighalpinecatchments.

Figure1:Wintermassbalancefor5elevationbands(winter1979/1980);greybars:10%and90%percentilesofallobservedpointmassba-

lances(Funk,1985),redbars:simulatedmeanmassbalance(modifiedGSM-SOCONTwithseasonalaccumulationandablationparame-

ters).

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Figure2.Comparisonofannualnetbalancesimulationsobtainedwiththedetailedglaciologicalmodelpresentedin(Hussetal.,2008)

andwiththesimplehydrologicalmodelGSM-SOCONT(withseasonalaccumulationandablationparameters),calibratedonseasonaldata,

onnetbalancedata(Funk,1985)orondischarge.

REFERENCESFunk,M.: RäumlicheVerteilungderMassenbilanz auf demRhonegletscherund ihre Beziehung zuKlimaelementen,

EidgenössischeTechnischeHochschuleZürich,Zürich,183pp.,1985.Huss,M.,Bauder,A.,Funk,M.,andHock,R.:DeterminationoftheseasonalmassbalanceoffourAlpineglacierssince1865,

JournalofGeophysicalResearch,113,F01015,10.1029/2007JF000803,2008.Schaefli,B.,Hingray,B.,Niggli,M.,andMusy,A.:Aconceptualglacio-hydrologicalmodelforhighmountainouscatchments,

HydrologyandEarthSystemSciences,9,95-109,2005.

4.16

Impact of snowmelt on zero curtain and thaw layer depth for different subsurface textures. Field and modeling- based studies at the Murtél- Chastelets area.

SchneiderSina,ScherlerMartin

Alpine Cryosphere and Geomorphology (ACAG), Department of Geosciences, University of Fribourg, Chemin du Musée 4, CH-1700 Fribourg

Thesummerzerocurtainphase,atimeperiodcharacterizedbyconsumptionoflatentheatinanisothermalsoilregionattemperaturesnearthemeltingpoint,isofhighimportanceforthethermalregimeofpermafrost.Itisassumedthatthemaincausefortheinitialisationofthesummerzerocurtainisthethawingofthesnowpackandthustheinfiltrationofmeltwaterintothefrozenactivelayer.Furthermoreweassumethattheevolutionofthezerocurtaindependsonthetextureofsubsurface.

BoreholetemperaturemeasurementsfromourfieldsiteMurtél-Chasteletsshowthatonfinegrainedmaterialtheisother-malregionismuchthickerthanincoarseblockymaterial.Inadditionweuseanumericalheatandmasstransfermodeltofurtherinvestigatetheinfiltrationprocessesonthesedifferentsubstrates.

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REFERENCES:Outcalt, S., F. E.Nelson, andK.M.Hinkel (1990). TheZero-CurtainEffect:Heat andMassTransferAcross an Isothermal

RegioninFreezingSoil.WaterResourcesResearch26(7),1509-1516.Kane,D.L.andJ.Stein(1983).WaterMovementIntoSeasonallyFrozenSoils.WaterResourcesResearch19(6),1547-1557.

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Using XPD for determining physical rock parameters of permafrost materials

TiloSchneider1,IldikoKatona-Serneels2

1 Institut für Geowissenschaften, Burgweg 11, 07749 Jena, Germany2 Department of Geoscience, Chemin du Musée 6, CH - 1700 Fribourg, Switzerland

Permafrostoccursindifferentsubstrates.Variabilityinrocktype,porosity,blocksizedistributionandweatheringattitudedeterminesmorphology,dynamicandicecontentofrockglaciersandtalusslopes.Toanalyzetheseconditionsgeophysicaltechniquessuchasgeoelectricsandseismicsareadequatemethodstodeterminepropertiesoftheshallowsurfaceinpermafrostregions.Eventhoughvaluesforthephysicalcharacteristicsoftheprevailingrockscanusuallybefoundinliterature,theymayvaryoverawiderange.Inordertocalculatemoredetailedmodelsofthesubsurface the physical rock parameters like electrical resistivity and acoustic impedance have to be known very well.Determiningthephysicalcharacteristicsofsinglemineralsmaythereforelimittheuncertaintiesofthewholegeophysicalrockanalysis.

Attypicalpermafrostmonitoringsites,suchastheMurtèl/ChasteletsareaintheEasternSwissAlps,severaldrillcoresandrocksampleswerecollectedandanalyzedusingX-RayPowderDiffractometry.Bythis,itispossibletodeterminethemineralcompositionoftherocksintheinvestigationarea.Inaddition,aReed-Fieldanalysiswasusedtocalculatethequantityoftherespectivemineralcontent.Thisenablestodeterminemeanphysicalrockpropertiesinthesubsurfacewhichthencanbeusedtoimprovegeophysicalmodeling.TheXPDanalysisisafastandexactmethodtodeterminethemineralcontentinrocksamplesqualitativelyandquantitatively.InthisstudyrocksamplesfromthreedifferentpermafrostareasintheSwissAlpshavebeenanalyzed.Allthreesites(Murtèl/Chastelets(GR),Schilthorn(BE),Stockhorn(VS))areincludedintheSwisspermafrostmonitoringnetworkPERMOS,whereboreholetemperatures,meteorologicaldataandgeophysicaldataarebeingcollectedextensively.Inourcontributionwewillpresentresultsfromthemineralanalysisandcomparethemtogeophysicalparametersobservedatthethreesites.

4.18

A systematic approach to quantify the performance of SNOWPACK

SteinkoglerWalter1,2,FierzCharles1,LehningMichael1,ObleitnerFriedrich2

1WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, CH-7260 Davos Dorf (Steinkogler@slf.ch)2Institute of Meteorology and Geophysics, Innsbruck University, Innrain 52, A-6020 Innsbruck

Newsnowsettlementintheveryfirsthoursanddaysafterasnowfallhasnotyetbeenfullyunderstood.Modellingerrorsatthisinitialstagepropagatethroughawholewinterseason,thusaffectingacorrectmodellingofcrucialsnowcoverproper-tiessuchasdensity,temperaturedistributionandsnowdepth.

Uptonow,parametertuningforsettlinginSNOWPACK(Lehning&Fierz,2008)hasmainlybeendonebyvisualcomparisonofmodelledwithmeasuredsettlingcurves.Thiscanbeaccomplishedbytrackingmodellayersthatcorrespondtopositionsofcombinedsettlementandtemperaturesensors(snowharps).Asaresult,verificationofmodelperformancewithinsitumeasurementsispossible.Herecomprehensivedatasetsobtainedduringanumberofsnowfallperiodsareused.Basedontheseobservationswepresentasystematicapproachtoassesstheperformanceofthemodel.Sensitivitystudiesallowtolocatethemostimportantmodelparameterswhichinfluencethesettlementofdepositedsnow.Ourapproachoffersthepossibilitytovisualiseandquantifytheperformanceofdifferentmodelruns.Inparticular,wewillpresentsuchananalysisbothduringandafewdaysaftersnowfalls.

REFERENCESLehning,M.,&FierzC.,2008:Assessmentofsnowtransportinavalancheterrain.ColdReg.Sci.Technol.,51(2-3),240–252.

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Mass balance of Brewster Glacier, New Zealand, modelled over three decades

DorotheaStumm1,FitzsimonsSeanJ1,CullenNicolasJ1,HoelzleMartin2,MachguthHorst3,AndersonBrian4&MackintoshAndrew5

1Department of Geography University of Otago, PO Box 56, Dunedin, New Zealand (dorothea.stumm@geography.otago.ac.nz)2Department of Geosciences, University of Fribourg, Chemin de musée 4, 1700 Fribourg3Department of Geography, University of Zurich, Winterthurerstr. 190, 8057 Zurich4 Antarctic Research Centre, Victoria University of Wellington, PO Box 600 Wellington, New Zealand 5 School of Geography, Environment and Earth Science, Victoria University of Wellington, PO Box 600 Wellington, New Zealand

TheaimofthisstudywastomodelthemassbalanceandsnowlinesonBrewsterGlacierforthepastthreedecades,byusingadistributedmassbalancemodel(Oerlemans,2001;Machguthetal.,2006).

Themassbalancemodelisbasedontheenergybalance,andrunswithmeteorologicalinputdata.Inputdataareaninter-polatedclimatedatasetfromtheNationalInstituteofWaterandAtmosphericResearch(NIWA),andtheERA-40re-analysisdataset from the European Centre for Medium-RangeWeather Forecasts (ECMWF). Directmass balancemeasurements,whichwereinitiatedin2004,provideddatatocalibratethemodel.Thesemeasurementswerecollectedwiththeglaciologi-calmethodthatincludesstakeandsnowpitmeasurements.Formodelvalidation,weusedtheannualend-of-summersnow-line(EOSS)recordsfromtheGlacierSnowlineSurvey(Chinn,1995;Willsmanetal.,2008),whichdocumenttheevolutionoftheBrewsterGlacierexcellentlysince1978.Aftercalibratingthemassbalancemodel,themassbalanceandsnowlinesweresimulatedforthepastthreedecades.ThemodellingresultswerethencomparedtotheyearlyEOSSrecords.

ThemassbalancemodelperformedwellwiththeinterpolatedNIWAdatasetforthecalibrationperiod.Butfortheprevious30years,themodelcalculationsdidnotcorrespondwelltotheEOSSrecords.Therefore,themodelinputdatasetwasex-changedwiththeERA-40re-analysisdata.TheresultscomparedmuchbettertotheEOSSrecords,andfitbetterwithmassbalanceestimatesfromaparameterisationscheme(Haeberli&Hoelzle1995)andaGPSmassbalancesurvey(Willisetal.,2008).Furthermore,massbalancetrendsweremodelledwell.However,spatialresolutionoftheERA-40datasetisverycoar-se,andwesuggesttestinginfuturestudieswhethertheperformanceofmassbalancemodellingcanbeimprovedbyapply-ingfinerresolutionRegionalClimateModeldatadrivenfromre-analysis.

REFERENCESChinn,T. J.1995:GlacierFluctuationsintheSouthernAlpsofNewZealanddeterminedfromSnowlineElevations.Arctic

andAlpineResearch,27(2),187-198.Haeberli,W.&Hoelzle,M.1995:Applicationofinventorydataforestimatingcharacteristicsofandregionalclimatechange

effectsonmountainglaciers-apilotstudywiththeEuropeanAlps.AnnalsofGlaciology,21,206-212.Machguth,H., Paul, F.,Hoelzle,M.&Haeberli,W. 2006:Distributed glaciermass balancemodelling as an important

componentofmodernmulti-levelglaciermonitoring.AnnalsofGlaciology,335-343.Oerlemans,J.2001:GlaciersandClimateChange.A.A.BalkemaPublishers,Lisse/Abingdon/Exton(PA)/Tokyo.Willis, I., Lawson,W.,Owens, I., Jacobel,B.&Autridge, J. 2008: Subglacialdrainage systemstructureandmorphologyof

BrewsterGlacier,NewZealand.HydrologicalProcesses,DOI:10.1002/hyp.7146.Willsman,A.,Salinger,M.J.&Chinn,T.J.2008:GlacierSnowlineSurvey2008.Technicalreport,NationalInstituteofWater

andAtmosphericResearchLtd.

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Natural and anthropogenic primary aerosols record from an Alpine ice core (Colle Gnifetti, Swiss Alps).

FlorianThevenon1,FlavioS.Anselmetti2,StefanoM.Bernasconi3&MargitSchwikowski4

1Institut F.-A. Forel, Université de Genève, CH-1290 Versoix (Florian.Thevenon@unige.ch)2 Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf3 Geological Institute, ETH Zurich, CH-8092 Zurich4 Paul Scherrer Institut, CH-5232 Villigen

TheColleGnifettiglacier,locatedintheMonteRosamassif (Swiss-Italianborder,4455ma.s.l.),satisfactoryconservestheaccumulationhistoryofsummerprecipitationchemistryandclimaticconditionsoverrelativelylongtime-period(i.e.afewhundredyears).Infact,theColleGnifettiglacierischaracterizedbyahighice-thickness(about60to130m)andalownetsnowaccumulationofabout30cmwaterequivalentperyear (weq.), resultingfromthepreferentialwinderosionofdrywintersnow.

Consideringthat1)theanthropogenicaerosolsaremostlydepositedinsummer,whenpollutedairistransporteduptohighaltitudesbyconvection,andthat2)duetoitsorographicalpositionintheSouthernAlpinechain,theColleGnifettiglacierisstronglyinfluencedbyairmassesadvectedfromsoutherlydirections,theColleGnifettisummerarchivesthereforeofferauniquepossibility for reconstructing i) regional (pre-)industrial carbonaceousaerosolemissions,and ii) changes in thedynamicofthesouthwesterlydust-ladenwindsfromtheSahara.

TheColleGnifettiicecoreanalysisdemonstratesthattheelementalblackcarbon(BC)aerosolrecordisindependentofthelarge-scaleclimaticcontrolaffectingthetransportofmineraldusttotheSouthernAlps,butprimarilyreflectsregional-scaleanthropogenicactivity(Thevenonetal.,2009).Moreprecisely,theδ13CcompositionofBCsuggeststhatwoodcombustionwasthemainsourceofpreindustrialatmosphericBCemissions.Moreover,biomassburningactivityandespeciallyC

4grassland

burningabruptlydroppedbetween1560and1750 (Figure1), suggestingthatagriculturalpracticesstronglydecreased inEuropeduringthiscoldperiodofthe‘LittleIceAge’.UnliketheBCdeposition,themineraldusttransporttothesummitsoftheSouthernAlpsisprimarilycontrolledbylarge-scaleclimaticpatterns(i.e.drierwinterinNorthAfricaandstrongerNorthAtlanticsouthwesterlies),leadingtotransportofmassivedustplumesfromtheSaharaaround1560-1685,1775-1785,andafter1860.Incontrast,theperiodsoflowSaharandustdepositionaround1515-1560,1690-1770and1790-1850mayindi-cateweakermeridionalatmosphericcirculationatthattimes,leadingtocolderanddrierspring/summerconditionsoverWesternandCentralEurope.

REFERENCEThevenon, F., F. S.Anselmetti, S.M. Bernasconi, andM. Schwikowski (2009).Mineral dust and elemental black carbon

records from anAlpine ice core (ColleGnifetti glacier) over the lastmillennium. J. Geophys. Res., 114,D17102,doi:10.1029/2008JD011490.

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Figure1.Thelastmillenniumrecordofblackcarbon(BC)concentrationandtheassociated δ13CBCcomposition,asafunctionofage(year

A.D.;leftaxis)anddepth(meterwaterequivalent,mweq;rightaxis).Thedigitalimagesofthefilters,thetotalandmineralaerosolre-

cords,andthemeandiameterofthemineralfraction.Thethreelastmajorsolaranomalousperiods,theSpörer,the(Late)Maunder,and

theDaltonMinima,arereportedforcomparison(Thevenonetal.,2009).(NextPage)

4.21

Impacts of climate change on 22 south-eastern Swiss glaciers from 1900 until 2100

UsselmannStephanie1,HussMatthias1,2&BauderAndreas1

1 Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zürich, CH-8092 Zürich (usselmas@vaw.baug.ethz.ch)2 Department of Geosciences, University of Fribourg, CH-1700 Fribourg

Sincethe1850s,theendoftheLittleIceAge,Alpineglaciershavesufferedmajorlossesoficevolume.Theimpactofclimatechangeonglaciersisreflectedmostclearlyintheirsurfacemassbalance.Therefore,areconstructionofmassbalancetimeseriesofdifferentglaciersduringthelastcenturyisimportantforabetterunderstandingoftheresponseofAlpineglacierstocurrentglobalwarming.

Inthisstudy,thetemporalandspatialchangesof22glaciersinthesouth-easternSwissAlpsareanalyzedbetween1900and2008usingdifferenttypesoffielddataanddistributedmodelling.Theinvestigatedglacierscoverawiderangeofglacierareaandicevolume,aswellasexposureandslope.Thisallowsinvestigationofdifferencesintheresponseofindividualglacierstoclimatechangeinarelativelysmallregion.

Seasonalmassbalancetimeseriesofglaciershavebeencalculatedfortheperiod1900–2008usingadistributedaccumula-tionandtemperature-indexmeltmodel(Hussetal.,2008).Themodeliscalibratedusingobservedicevolumechangesinmultidecadalperiods.Inordertocalculatethevolumechange,twosuccessivedigitalelevationmodels(DEMs)arecompared

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ion toeachother.ThebasisfortheseDEMsare(i)terrestrialtopographicsurveys,(ii)photogrammetricanalysisofaerialphoto-

graphs,and (iii)alreadyexistingdatasets,asDHM25(swisstopo)andSRTM(NASA). In-situpointmeasurementsofannualmassbalanceandwinteraccumulation,available for someglaciers, aswell as long-termdischarge records for the threemajorcatchmentsinthestudyregionareusedformodelvalidation.

Since1900thechangesinglacierareaandvolumeareconsistentlynegative.Betweenthe1930sandtheendofthelastcen-turytheareaofthe22investigatedglaciersdecreasedbyabout24%.Overthelastcentury(1900–1999)theregionalicevo-lumehasdecreasedby30%,withstrongdifferencesbetweenindividualglaciers(20–60%).Therateof100-yearmasslossstronglydiffersbetweenadjacentglaciers.Whereaslargevalleyglaciers(e.g.VadrecdelForno)showcumulativemassbalan-cesofupto-70mw.e.,smallerandsteeperglaciers(e.g.VadretdaPalü)exhibitlessnegativemassbalancesofaround-15mw.e.(Fig.1).Usingregionalclimatescenarios(Frei,2007),futureglacierretreatissimulatedtransientlyforallglaciersoverthe21stcen-tury.Weprojectglacierareachangesbetween-80%and-100%andvolumechangesbetween-70%and-100%withstrongim-pactsonthewatercycle(Fig.2).

Figure1.Cumulativeseriesofmeanspecificmassbalanceofthe22investigatedglaciersfrom1900to2008.Timeseriesfortheindividual

glaciersaredisplayedingrey;trianglesindicatethedatesofDEMs.Thesolidvioletlinerepresentsthearithmeticaveragefortheinvesti-

gatedglaciers.Glaciernamesaregivenattheright-handsideandcoloursindicateglaciersize(Usselmann,2009).

Figure2.SimulatedfutureevolutionofVadretdaMorteratschuntil2100.Glacierextentisshownfortheyears2020,2060and2100forthe

mostlikelyclimatescenario.Glacierextentintheyear2008isshown(Usselmann,2009).

REFERENCESFrei,C.,2008.DieKlimazukunftderSchweiz.In:KlimaänderungunddieSchweiz2050–ErwarteteAuswirkungenaufUmwelt,

GesellschaftundWirtschaft.BeratendesOrganfürFragenderKlimaänderung(OcCC):12–16,http://www.occc.ch.Huss,M.,Bauder,A.,Funk,M.&Hock,R.,2008.DeterminationoftheseasonalmassbalanceoffourAlpineglacierssince

1865.JournalofGeophysicalResearch,113,F01015.Usselmann, S., 2009. SchweizerGletscher imWandel vonKlimaundZeit.Diplomarbeit, Friedrich-Alexander-Universität

Erlangen-Nürnberg,pp.179.

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Understanding rapid dynamic changes of marine Greenland outlet gla-ciers from numerical modeling

AndreasVieli12,FaezehM.Nick3

1 VAW, Glaziologie, ETH Zuerich, Gloriastr 37/39, CH-8092 Zuerich 2 Department of Geography, Durham University, South Road, Durham DH1 3LE, UK (andreas.vieli@Durham.ac.uk.ch)3GEUS, Ostervolgade 10, DK-1350, Copenhagen, DK

RecentrapiddynamicchangesofGreenland'soutletglaciersraisedconcernsoverthecontributiontofuturesealevelrise.ThesedynamicchangesseemtobelinkedtothewarmingtrendinGreenland,butthemechanismsthatlinkclimateandicedynamicsarepoorlyunderstood,andcurrentnumericalmodelsoficesheetsarenotabletosimulatethesechangesrealis-tically.ThesedynamicchangesthereforeprovidemajoruncertaintiesinthepredictionsofmasslossfromtheGreenlandicesheet. Wedevelopedanumerical ice-flowmodelthatreproducestheobservedrapidchanges inHelheimGlacier,oneofGreenland'slargestoutletglaciers.Oursimulationsshowthattheiceacceleration,thinningandretreatbeginattheoceanterminatingcalvingfrontandthenpropagaterapidlyupstreamthroughdynamiccouplingalongtheglacier.Wefindthatthesechangesareunlikelytobecausedbybasallubricationthroughenhancedsurfacemeltfromtherecentatmosphericwarmingandthatmasslossisamplifiedbyadeepbasaloverdeepeningatthebed.Importantly,themodellingfurthershowsthatsuchtidewateroutletglaciersareextremelysensitivetochangingboundaryconditionsatthecalvingterminusanddynamicallyadjustextremelyrapidly.ThisimpliesthattherecentrapidmasslossofGreenland'soutletglaciersmayreflectshort-termvariationsinclimateoroceanconditionsandshouldnotbeextrapolatedintothefuture.

4.23

Hazard assessment investigations in connection with the formation of a lake on the tongue of the Unterer Grindelwaldgletscher, Bernese Alps, Switzerland

MauroA.Werder1,AndreasBauder1,Hans-RudolfKeusen2,MartinFunk1

1VAW, ETH Zurich, CH-8092 Zurich, Switzerland (werder@vaw.baug.ethz.ch)2GEOTEST AG, Birkenstrasse 15, CH-3052 Zollikofen, Switzerland

ThesurfaceleveloftheUntererGrindelwaldgletscherglaciertonguehassubsidedbymorethan200\,moverthelast150years.Thesurfaceloweringisnotuniformovertheglaciertonguebutdependsonthethicknessoftheunevendebriscover,whichledtotheformationofadepressiononthetongue.Alakehasformedinthisbasin,forthefirsttimein2005,whichcandrainrapidlyleadingtoaso-calledglacierlakeoutburstflood.Thelakebasinhasbeenincreasinginsizeatanalarmingrateand,in2008itreachedavolumewhichposesasignificantfloodingthreattothecommunitiesdownstream,aswasexemplifiedbyanoutburstofthelakeinMay2008.Weextrapolatedthefutureevolutionofthelakebasinbasedonsurfaceloweringratesin2004--2008.Wetunedamodelwiththemeasuredhydrographfrom2008andranitwiththeextrapolatedlakevolumestosimulatesuchalakeoutburstandestimatedpossiblefuturefloodhydrographs.Wediscusstherapidlyin-creasingriskforGrindelwaldandothercommunities,thereasonswhyin2009norapidlakedrainageoccurred,aswellastheinstallationofanearlywarningsystemandtheconstructionofa2.1kmlongdrainagetunnel.

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Analysis of temporal and spatial snow depth changes in a steep rock face

VanessaWirz,MichaelSchirmer,MichaelLehning

WSL-Institut für Schnee- und Lawinenforschung SLF, Flüelastrasse 11, CH-7260 Davos Dorf (wirz@slf.ch)

Thepresenceofsnowinsteepalpineterrainaffectsmanyphenomena,e.g.watermanagement,snowavalanchesorperma-frostdistribution.Hencegoodknowledgeonspatialandtemporaldistributionof snowinsteepalpine terrain isofhighimportance.Inaccessibilityandalpinedangersinverysteepterrainarethemainreasonsforlackofstudiesonsnowdepthinthoseareas.Themaingoalofthisstudyistogetmoredetailedinformationabouttheamountanddistributionofsnowinverysteepterrainandtobetterunderstandtherelevantprocessesandfactors,whichaffectsnowaccumulation,redistri-bution,erosionandablationinsteeprockfaces.Forthispurpose,ahighresolutionterrestrialLaserScanner(TLS)wasusedproducingprecisesnowheightdigitalsurfacemodels.Wecollectedsurfacedatawithoutsnow,beforeandaftersignificantsnowfallorwinddrifteventsandduringtheablationperiod.Wethengenerateddigitalsurfacemodels(DSM)foreachob-servationperiod.Thesummerscanunderthetotalabsenceofsnowallowedustoprovideadigitalelevationmodel(DEM)andtocalculateabsolutesnowdepth.Relativesnowdepthchangescanbeextractedbythecomparisonofdifferentwinterscans.Inadditiontothelaserscans,orthophotosweretakenwithadigitalcamera.

InafirststepwecouldshowthatwithTLSreliableinformationonsurfacedataofasteeprockysurfacecanbeachieved.Incomparisontoaflatfieldpointmeasurementthemeansnowdepthintherockfacewassmallerduringtheentirewinter,buttrendsofsnowdepthchangesweresimilar.Weobservedrepeatingaccumulationandablationpatternsintherockface,whilemaximumsnowdepthlossoccurredalwaysatthoseplaceswithmaximumsnowdepthgain.Furthermore,increasingsnowdepthresultedinadecreaseofhighslopeangles.Furtheranalysesshouldinvolvethestatisticalrelationofspatialandtemporaldistributionofsnowdepthto(i)terrainfeaturese.g.slopeangle,aspectorcurvatureand(ii)resultingsurfacepro-cessesderivedfromspatialdistributedmodeloutputse.g.radiation,windfieldsorblowinganddriftingsnow.

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y 5. Meteorology and climatologyRolf Philipona, Markus Furger

Swiss Meteorological Society

5.1 CeppiP.,ScherrerS.C.,AppenzellerC.:MagnitudeandaltitudedependenceofSwisstemperaturetrends: localandlarge-scaleinfluences

5.2 ChiacchioM.,EwenT.,WildM.,ChinM.,DiehlT.:DecadalvariabilityofaerosolopticaldepthinEuropeanditsrela-tionshiptotheglobaldimmingandbrighteningandtheshiftintheNAO

5.3 EwenT.,BrönnimannS.:PacificNorthAmericanclimatevariabilityandlinkstotheNorthAtlantic

5.4 FallotJ.-M.,HertigJ.-A.:AssessmentofextremeprecipitationinSwitzerlandwithstatisticalanalyses

5.5 HauckC.,KraussL.,BarthlottC.:Soilmoisturemonitoringandsoilmoistureimpactonconvectiveprecipitationinorographicterrain

5.6 MeierM.F.,GrobétyB.,CollaudCoenM.:AerosolpropertiesofSaharandustcollectedattheJungfraujoch:determinedbysingleparticleanalysis

5.7 PiquetE.,DeljuA.,KaenzigR.:Selectingandproducingclimaticdatatoassesstheclimatechange/humanmigrationnexus

5.8 RossiL.,MargotJ.,HariE.R.:Watertemperaturechangesinreceivingwatersduetotheincreaseofimperviousness:amultidisciplinaryassessmentapproach

5.9 Schaller N., Mahlstein I., Knutti R.: Should climate models be evaluated with statistic-based or process-basedmetrics?

5.10 Stocker-Mittaz C., Häberli C., Frei C., Germann U.: The MeteoSwiss strategy for the renewal of the precipitationmeasurementnetwork

5.1

Magnitude and altitude dependence of Swiss temperature trends: local and large-scale influences

CeppiPaulo,ScherrerSimonC.,AppenzellerChristof

Climate Services, Federal Office of Meteorology and Climatology (MeteoSwiss), Zürich, Switzerland (Paulo.Ceppi@meteoswiss.ch)

EventhoughtheincreaseinCentralEuropeantemperaturesoverthelastdecadesisundisputed,thealtitudedependenceofwarmingtrendsisstillsubjecttomanyuncertainties.Whilemostreanalysesandmodelprojectionsindicateanincreaseofwarmingeffectswithaltitudeinthemid-latitudelowertomiddletroposphere(seeIPCC2007),studiesbasedonobservationsyield lessclearresults, sometimes incontradictionwithmodel-basedanalyses (e.g.Bradleyetal.2004,Appenzelleretal.2008).Furthermore,thenatureandeffectsofthephysicalprocessesresponsibleforthealtitudedependenceofthetrendsareonlypartlyknownandrequirefurtherinvestigation.

ThispaperaimsatestimatingcurrenttemperaturetrendsinSwitzerlandandatassessingtheiraltitudedependence.WeappliedtrendanalysismethodstoanewgriddedSwisstemperaturedataset,generatedatMeteoSwiss fromstation-basedhomogenisedtemperaturerecordsforthetimeperiod1959-2008(Begertetal.2005).Usingdifferenttemporalresolutions

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gy (yearly,seasonalandmonthly),we investigatedthemagnitudeofrecentwarminganditsaltitudedependence.Fromthe

resultsofthetrendanalysis,weattemptedtoidentifypossiblephysicalmechanisms(e.g.largescaledynamicsorlocalfactorssuchassnowpackorfog)explainingtheverticaldependenceofthetemperaturetrends.

Ourresultsindicatethatyearlytrendsarepositiveandstatisticallysignificantatthe95%levelforallofSwitzerland,withvaluesbetween0.23and0.44°Cperdecade.However,seasonalvariationsareconsiderable.Thetrendsarestrongestinsum-mer(0.34to0.62°C/decade)andweakestinautumn(-0.02to0.38°C/decade).Usingmultipleregressionmodels,weshowthatglobaltemperaturevariationsandchangesinlargescaledynamicscannotexplainthefullamplitudeoftheobservedtem-peraturetrendsinSwitzerland.Thisindicatesthatsmallerscaleandlocaleffectsmightplayanimportantrole.

Thetemperaturetrendsshowsomealtitudedependence,buttheimportanceofthiseffectisstronglydependentonseason.Whileyearlytrendsshowaslighttendencytowardsdecreasingmagnitudeswithaltitude,thereisamuchclearersignalinearlyspringandautumn,withtrendsbeingmuchstrongerinlowlandregionsthaninthemountains(seeFig.1).

Furthermore,ourobservationsshowthatduringspring,thestrongestwarmingsignalpropagatestowardshigheraltitudeswithtime,followingthe0°Cisothermandtheincreasingaltitudeofthesnowline.Thisisconsistentwithfindingsinothermountainousregions(Pepin&Lundquist2008).Theobservedheightdependencesinspringhavebeeninterpretedasresult-ingfromreducedsnowcover,implyingchangesinsurfacealbedoandsurfaceenergybudget.Thestrongertrendsatlowal-titudesinautumnarestillunderinvestigation.Potentialmechanismsleadingtothisdifferenceareadecreaseinfogdayfrequencyinthelowlandsoverthelastdecadesand/orchangesinfoehnfrequency,atleastinthemainfoehnregions.

Figure1.Temperaturetrends(°C/decade)inOctoberfrom1959to2008.Shadingdenotesnon-significanttrendsatthe95%level.Notethat

thetrendsexhibitaclearaltitudedependencewithhighervaluesatlowerstations.

REFERENCESAppenzeller,C.,Begert,M.,Zenklusen,E.&Scherrer,S.C.2008.MonitoringclimateatJungfraujochinthehighSwissAlpine

region.ScienceoftheTotalEnvironment,391(2-3):262-268.Begert,M.,Schlegel,T.&Kirchhofer,W.2005.HomogeneoustemperatureandprecipitationseriesofSwitzerlandfrom1864

to2000.Int.J.Climatology,25(1):65-80.Bradley,R.S.,Keimig,F.T.&Diaz,H.F.2004.ProjectedtemperaturechangesalongtheAmericancordilleraandtheplanned

GCOSnetwork.GeophysicalResearchLett.,31(16).Pepin,N.C.&Lundquist,J.D.2008.Temperaturetrendsathighelevations:Patternsacrosstheglobe.GeophysicalResearch

Lett.,35(14).IPCC2007.ClimateChange2007:ThePhysicalScienceBasis.ContributionofWorkingGroup I to theFourthAssessment

ReportoftheIntergovernmentalPanelonClimateChange.CambridgeUniversityPress.

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Decadal variability of aerosol optical depth in Europe and its relationship to the global dimming and brightening and the shift in the NAO

MarcChiacchio1,TracyEwen1,3,MartinWild1,MianChin2,ThomasDiehl2

1 Institute for Atmospheric and Climate Science ETH, Zurich, Switzerland2 NASA Goddard Space Flight Center, Greenbelt, Maryland, USA3 Department of Geography, University of Zurich, Zurich, Switzerland

TrendsofaerosolopticaldepthfromtheGoddardChemistryAerosolRadiationandTransport(GOCART)Modelaredetectedaccordingtotheirannualandseasonaltemporalresolutionfortheperiod1979-2007.DuringthistimeaerosolemissionsinEuropehavedeclinedduetoenvironmentalregulationsimposedtocontrolairpollution.BydoingsoitisbelievedthatthishasaffectedtheamountofsolarradiationthatreachesthesurfaceoftheEarth,whichhasupsetthesurfaceradiativebal-ance,hence,globaldimmingandbrightening.Thoughcloudshavealsoplayedaroletothedecadalchangesinsurfacesolarradiation,theinter-relationshipbetweenthesevariablesarestillnotwellknownandtheirroleamongoneanotherhasnotyetbeenquantified.ThroughvariousstatisticaltechniquesweshowtherolethataerosolsplayontheglobaldimmingandbrighteningaccordingtoaseasonalanalysisaswellastheirroleontherelatedatmosphericcirculationthatisdominantinEurope,suchastheNorthAtlanticOscillation(NAO).ItiswellestablishedthattheNAOmainlyaffectstheclimateinEuropeinwinter.Inrecentdecades,largechangesintheNAOhaveoccurredwithalargepositivetrendintheindexafterabout1980,andithasaccountedformuchofthewarminginEurope.ThislargepositivetrendintheNAOalsooccursatthesametimethataerosolemissionsinEuropeweregreatest,whichmightimplythattheycouldbecontributingtothechangesintheNAOandcontrollingthesolarradiationonadecadalscale.

5.3

Pacific North American climate variability and links to the North Atlantic

TracyEwen1,2&StefanBrönnimann2

2Institute for Atmospheric and Climate Science, ETH Zurich, Universitätstr. 16, 8092 Zurich. 1Department of Geography, University of Zurich, Winterthurerstr. 190, 8057 Zurich, (tracy.ewen@geo.uzh.ch)

ClimatevariabilityinthePacific-NorthAmericanregionisoftenanalysedintermsofafewdominantmodesofvariability,suchasthePNAandPDO.WhilethePNApredominantlycharacterisesvariabilityonseasonaltointerannualtimescales,thePDO isoftenused tocharacterisedecadal scalevariability. Similarly, variability in theNorthAtlanticEuropeansector isanalysedintermsoftheNAO(seasonal-to-decadal)andAMO(decadal-to-centennial).

Untilrecently,thePNAindexhasonlybeenavailablebackto1948,asitisdefinedbasedon500hPageopotentialheightdata.Usinghistoricalupper-airdata,wehavereconstructedamonthlyindexbackto1920(Ewenetal.,2008),whichnowallowsdecadal-scalevariabilitytobeassessed.WeanalysethisindextogetherwithENSO(NINO3.4),PDO,NAO,andAMOindicesinthetime-frequencydomainandfurtherassessthestationarityandphaserelationshipoftheindices.WefindstablerelationsbetweenthePNAandallotherindices,butatdifferenttimescales.ENSOandPNAshowcoherentbehaviourinthe4-8yearperiod.Wealsofindcoherentlow-frequencyvariability(forperiodslongerthan10yrs)betweenthePNAandPDO.Thecor-relationbetweenPNAandNAOisweak(butsignificant)inlatewinter,andtimeintervalswithsignificantcoherencyarefoundontheinterannualscalebutalsoontheinterdecadalscale.Finally,weanalyseperiodsofcoherencybetweenthein-dicesintermsoftheirclimaticsignificance,inparticulartotheArcticwarmingduringthe1930sandtheNorthAmericanDustBowldroughtinthe1920s(Brönnimannetal,2009).

REFERENCESBrönnimann,S.,T.Griesser,A.Stickler,T.Ewen,A.N.Grant,A.M.Fischer,M.Schraner,T.Peter,E.Rozanov,T.Ross,2009:

Exceptional atmospheric circulationduring theDustBowl, to appear inGeophys.Res. Lett., 36, L08802,doi:10.1029/2009GL037612.

Ewen,T.,S.BrönnimannandJ.Annis,2008:AnextendedPacificNorthAmericanindexfromupperairhistoricaldatabackto1922.J.Climate,21(6),1295-1308.

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Assessment of extreme precipitation in Switzerland with statistical analyses

FallotJean-Michel1,HertigJacques-André2

1Institut de Géographie, Université de Lausanne, Dorigny-Anthropole, CH-1015 Lausanne (Jean-Michel.Fallot@unil.ch)2Hertig&Lador SA, Grand Rue 38, CH-1176 St Livres

ExtremeprecipitationandfloodeventsproducethegreatestdamagesduetonaturalhazardsinSwitzerland.Extremepre-cipitationamountsforareturnperiodof500yearsaregenerallyusedforcalculatingtheidealdimensionsofprotectionstructureagainstfloodings.TheSwissFederalInstituteforForest,SnowandLandscapeResearch(WSL)calculatedtheseex-tremeprecipitationvaluesfromstatisticalanalysescarriedoutonrainfalltimeseriesatabout300locationsinSwitzerlandovertheperiod1901-1970(Zelleretal.,1980).SeveralstudiesshowthatfrequencyofstrongprecipitationhasincreasedinSwitzerlandandintheworldwiththeglobalclimatewarming(Fallot,2000;Freietal.,2000;IPCC,2007):Forthisreason,daily(24-hour)extremeprecipitationvaluesforareturnperiodof500yearswererecalculatedfromGumbelanalysescarriedoutonrainfalltimeseriesmeasuredat429locationsinSwitzerlandovertheperiod1961-2008.Previous studies show that Gumbel analyses give the best results for estimating daily extreme precipitation values inSwitzerlandforareturnperiodof100or500years(Zelleretal.,1980).Ourstudyshowsthattheseextremevaluescanbewellestimatedatmostlocations(75%)inSwitzerlandfromsuchanalyses.Ontheotherhand,dailyextremeprecipitationvaluesaremoreorlessunderestimatedforasmallnumberofstations(7%).Resultsofthesenewanalysesalsorevealthatdailyextremeprecipitationvaluesestimatedforareturnperiodof500yearsovertheperiod1961-2008areinaverage14%higherthansimilarvaluescalculatedfortheperiod1901-1970.For31%ofsta-tions,dailyextremeprecipitationvaluesforareturnperiodof500yearsestimatedfromrainfalltimeseriesovertheperiod1901-1970onlycorrespondtoextremevaluesforareturnperiodof100yearsfortimeseriesovertheperiod1961-2008.Thisconfirmsthatextremeprecipitationvalueshaveincreasedandtheycouldcastadoubtovertheidealdimensionsofprotec-tionstructureagainstfloodinginsomeareainSwitzerland.Figure1showsthatdailyextremeprecipitationvaluesforareturnperiodof500yearsaremuchhighersouthoftheAlps(upto560mmin24hours)duetoitshighexposuretowetandwarmairmasscomingfromMediterraneanSea.

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outonrainfalltimeseriesat429locationsovertheperiod1961-2008.

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y However,extremeprecipitationvaluescanonlybeknownatpreciselocationsfromGumbelanalyses.Butthesevaluesstron-glyvarywithinacatchmentareainacomplextopographywhatcanaffectfloodscalculations.Thus,athree-dimensionalmeteorologicalmodelwasdevelopedforcalculatingextremewindsandprecipitationevery2kmat thehorizontalscale(Audouardetal.,2006).Resultsofthismodelwerecomparedwithdailyextremeprecipitationvaluesforareturnperiodof500yearsestimatedfromrainfalltimeseriesoverperiod1961-2008.Thiscomparisonshowsaquitegoodagreementbetweenthemodelandextremevaluesestimatedfromfieldmeasurements,buttheyarealsoseveraldifferencesduetosomeappro-ximationsinthemodel.

REFERENCESAudouardA.,HertigJ.-A.,FallotJ.-M.,2006:ModélisationdesprécipitationsextrêmesenSuisse.Actesdu19èmecolloquede

l’AssociationInternationaledeClimatologie,Epernay,6-9-9.2006,p.83-88.Fallot J.-M., 2000: Evolutiondunombrede jours avecdesprécipitations abondantes en Suissedurant le 20ème siècle.

Publicationsdel’AssociationInternationaledeClimatologie,13,100-108.FreiC.,DaviesH.C.,Gurtz J., SchärC., 2000:Climatedynamics andextremeprecipitationand floods events inCentral

Europe.IntegratedAssessment,1,281-299.IPCC, 2007: Climate Change 2007. The physical science basis.WorkingGroup 1 to the fourthAssessment Report of

IntergovernmentalPanelonClimateChange(IPCC),CambridgeUniversityPress,Cambridge,UK,996p.Zeller J., Geiger H., Roethlisberg G., 1980: Starkniederschläge des schweizerischen Alpen- und Alpenrand-Gebiet.

EidgenössischeForschungsanstaltfürWald,SchneeundLandschaft(WSL),Birmensdorf.

5.5

Soil moisture monitoring and soil moisture impact on convective precipi-tation in orographic terrain

HauckChristian1,KraussLiane2,BarthlottChristian2

1Department of Geosciences, University of Fribourg, Chemin du Musée 4, 1700 Fribourg 2Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology, Germany

Soilmoistureisanimportantparameterinthesoil-atmospheresystem,whichinfluencesthehydrologyaswellastheavaila-bilityofmoistureintheplanetaryboundarylayer(PBL).ThelatterismainlycontrolledbytheenergybalanceattheEarth’ssurface,large-scaleadvection,andadvectiononthemesoscaleexhibitingadailycycle.Atleastinsituationswithlowsynop-ticforcing,thePBLcharacteristicsandtheirimpactsonthetriggeringand/ordynamicsofconvectivestormsarestronglyinfluencedbythepartitioningofavailableradiationenergyintosensibleandlatentheatwhichitselfisdeterminedbysoilmoisture.

Whereaspreviousobservationalandmodellingstudiesdemonstratedthatsoilmoisturecanindeedstronglycontributetothevariabilityofsurfacetemperatureandprecipitationoverflatterrain,theinfluenceofsoilmoistureonconvectioniniti-ationandprecipitationincomplexterrainhasnotbeeninvestigatedindetail.Inthiscontributionwewillshowresultsofadatasetfromasoilmoisturenetworkwithintheorographicallycomplexter-rainoftheBlackForest/RhineValleyinSouthwesternGermany,whichwasinstalledintheframeworkoftheinternationalCOPScampaign(ConvectiveandOrographically-inducedPrecipitationStudy).Inadditiontosoilmoisture,soiltemperature,anddata fromenergybalance, radiosonde stationandprecipitationnetworksareavailable toanalyse the impactof soilmoistureonconvectiveprecipitation(Wulfmeyeretal.2008,Kottmeieretal.2008).Modelstudiesusinganonhydrostaticlimited-areaatmosphericpredictionmodel(COSMO-DE)areusedtocomparemodelledandobservedsoilmoistureandpre-cipitationfields.

Thesoilmoisturemonitoringnetworkconsistsofmorethan50stationsand160singlesensorsmeasuringverticalprofilesofsoilmoisture(5,20and50cmdepth).Basedonregionaldifferencesbetween4distinctregionswithintheinvestigationarea soilmoisture is analysed regarding their variabilitywith respect to soil textureproperties, altitude and exposition(luv/lee).Eachsensor (newlydevelopedlow-costsensorSISOMOP)wascalibratedaccordingtothepropertiesofthesoil.AthoroughanalysisofthesoilatthevarioussoilmoisturestationsshowsthattheactualsoiltexturesoftendifferfromtheonesusedfortherespectivegridpointintheoperationalsoilmodelCOSMO/TERRA.Consequently,firstresultsfromacom-parisonbetweensimulatedandmeasuredsoilmoisturevaluesshowstrongdifferenceswithameanbiasaround20-30%formostofthestationsandmeasurementdepths.

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near-surfacevariablesandPBLcharacteristicsislargerunderweaksynopticforcingthanforstrongsynopticforcing,modelsimulationsandobservationalevidencerevealedthattheimpactofsoilmoistureisnotsystematicallyhigherforboundary-layerforcingmechanisms.Inthemodelsensitivityexperiments,theBowenratioexhibitsacleardependencetosoilmoistureconditions,butthesoilmoistureimpactonprecipitationismuchmorecomplexanddependsalsoonitsinfluenceoncon-vectiveindices,i.e.convectiveavailablepotentialenergy(CAPE)andconvectiveinhibition(CIN).Aconsiderable,butnotsy-stematicfeedbackofconvectiveprecipitationwithsoilmoistureexistsinthecomplexorographyanalysed.Theresultsde-monstratethehighimportanceofaccurateinitialsoilmoisturefieldsinnumericalweatherpredictionmodels.

REFERENCESKottmeier,Ch.,N.Kalthoff,U.Corsmeier,Ch.Barthlott, J.VanBaelen,A., Behrendt,R.Behrendt,A.Blyth,R.Coulter, S.

Crewell,M.Dorninger,C.,Flamant,Th.Foken,M.Hagen,C.Hauck,H.Höller,H.Konow,M.Kunz,H.,Mahlke,S.Mobbs,E.Richard,R.Steinacker,T.Weckwerth,A.Wieser,&V.WulfmeyerV.2008.MechanismusinitiatingdeepconvectionovercomplexterrainduringCOPS.Meteorol.Z.,17(6),931-948.

Wulfmeyer, V., Behrendt, A., Kottmeier, Ch., Corsmeier,U., et. al. 2008. TheConvective andOrographically-inducedPrecipitation Study:AResearch andDevelopment Project of theWorldWeatherResearch Program for ImprovingQuantitativePrecipitationForecastinginLow-mountainRegions.Bull.Amer.Meteor.Soc.,89(10),1477-1486.

5.6

Aerosol properties of Saharan dust collected at the Jungfraujoch: deter-mined by single particle analysis

MeierMarioFederico1,GrobétyBernard1,2&CollaudCoenMartine3

1Dept. of Geosciences, University of Fribourg, Chemin du Musée 6, CH-1700 Fribourg (mario.meier@unifr.ch)2Fribourg Center for Nanomaterials (FriMat), Univ. of Fribourg, CH-1700 Fribourg3MeteoSwiss, Aerological Station, CH-1530 Payerne

Mineraldustcanhaveapronouncedeffectontheopticalparametersoftheaerosol.DuringSaharanDustEvents(SDE)aninversionofthewavelengthdependenceoftheSingleScatteringAlbedo(SSA)isobserved(CollaudCoenetal.,2004).TheaimofthisstudyistoanalyseaerosolparticlesfromaSDEtodeterminetheirsizedistributionbetween0.4and10micrometers,theirmorphologyandtheirmineralcompositioninrelationwiththeobservedopticalmodifications.

ForthispurposePM10wasactivelysampledontoNuclepore®filtersatthehighaltituderesearchstationJungfraujoch(3580m.a.s.l.),beforeandduringaverystrongSDEwhichoccurredbetween26.and29.5.2008.CalculatedbacktrajectoriesshowthattheairmassesbeforetheSDEcamefromtheWest(France,SouthernSpain)andduringtheSDEfromtheSouth.ThesourceregionofthemineraldustcollectedduringtheSDEwasEastLibyaandTunisia.Theaerosolwas,therefore,transpor-tedstraightacrosstoMediterraneanSeatowardstheAlps.

StereologicalandchemicalsingleparticleanalyseswereperformedbyComputerControlledScanningElectronMicroscopy(CCSEM)coupledwithEnergyDispersiveSpectroscopy(EDS).Withthisautomatedtechniqueitwaspossibletoobtainchemi-calandmorphologicalparametersofabout2000particlesforeachsample.Aerosolparticleshavealsobeendirectlycollectedwith an electrostatic sampling device on carbon coated copper grids for analysis by Transmission Electron Microscopy(TEM).

Themineralogy,determinedbyCCSEM,wasnotclearlydifferentforaerosolcollectedbeforeandduringtheSDE.Allsamplesare dominated by clayminerals, followed by feldspars, gypsum, quartz and carbonates. Individual, well separated ironoxides,partiallysuspectedascausesforinversionofthewavelengthdependenceoftheSSA,wererare.However,detailedanalyseswithTEMofparticlesfromtheSDEshowedthatinclusionsofironandtitaniumoxideswithintheclayparticlesarecommon.Thesizeoftheseinclusionsisbetween10and200nm.DuringtheSDEanincreaseofthetotalaerosolmasscon-centrationwasobserved.Thevaluesraisedfrom100-200ngm-3priortotheSDEtovalues>10.000ngm-3.TheparticlesizedistributionshowsaclearcorrelationwiththeinversionoftheSSAwavelengthdependence.ForalldayswithnegativevaluesoftheSSAexponent,theconcentrationofparticleswithdiameterssmallerthan1.5µmisproportionallytotheconcentra-

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y tionofbiggerparticlesenhanced.Themineraltypecontributingmosttothissizefractionareclayparticles.Forparticles>1µmthescatteringbecomesdominatedbygeometricaloptics.Thisleadstoawavelengthindependenceofthescatteringco-efficient.

TheresultscorroboratethepreviousexplanationoftheSSAwavelengthdependenceinversioncausedbyarelativechangeinthesizedistributionoftheaerosolparticlesandbythepresenceofironoxides.Theironoxidesoccurasinclusionswithsizesbetween10and200nminclayparticleswithsizesbetween0.5and5µm.

REFERENCESCollaudCoen,M.,Weingartner,E.,Schaub,D.,Hueglin,C.,Corrigan,C.,Henning,S.,Schwikowski,M.&Baltensperger,U.

2004:SaharandusteventsattheJungfraujoch:detectionbywavelengthdependenceofthesinglescatteringalbedoandfirstclimatologyanalysis,AtmosphericChemistryandPhysics,4,2465-2480.

5.7

Selecting and producing climatic data to assess the climate change / human migration nexus

EtiennePiguet1,AmirDelju2,RaoulKaenzig3

1Institut de géographie, Université de Neuchâtel, Espace Louis-Agassiz 1, CH-2000 Neuchâtel (Etienne.Piguet@unine.ch)2World Meteorological Organization, 7bis av. de la Paix, CH 1211 Genève-2 (adelju@wmo.int)3Institut de géographie, Université de Neuchâtel, Espace Louis-Agassiz 1, CH-2000 Neuchâtel (Raoul.Kaenzig@unine.ch)

SincetheIPCC(2007)reportmentionedpopulationdisplacementsasaforeseeableconsequenceofclimatechange,numer-oussynthesispapersandcasestudieshavebeenpublishedaboutthepast,presentandfuturemigratoryconsequencesofenvironmentaldegradations(Knivetonetal.,2008;Piguet,2008).Anumberofinternationalconferencesandexpertwork-shopstookplaceandanimpressivecoordinatedresearchprojectin23regionsoftheworldwasachieved(http://www.each-for.eu/).Thevarietyofempiricalmethodsusedintheseresearchesis impressive,rangingfromqualitativeinterviewsandhistoricalanalogiestorepresentativequestionnairesurveys,andhighlysophisticatedquantitativemethods.

Severaloftheexistingresearchesalreadyuseclimaticdatasuchasrainfall(Barriosetal.,2006),droughtfrequencies(Henryetal.,2003)orhurricanesfrequencies(AfifiandWarner,2008)butsuchdataareinourviewclearlyunderuseduptonow.Thisisdueinparttoalackofdialoguebetweenmigrationsscholarsandclimatologists/meteorologists.Inordertobridgethisgap,thepaperwillpresentacriticalassessmentofthedifferentmethodsusedtoconnectenvironmentalchangeandmigrationandoftheuseofmeteorologicalandclimaticdatainthatcontext.Onthatbasis,wewillpresentanoverviewofthedatawhichcouldbeusedorshouldbeproducedinordertoimprovethestudyoftheenvironment/climatechangemigra-tionnexus

REFERENCESAfifi, T. andWarner,K. 2008: The Impact of EnvironmentalDegradationonMigrations Flows acrossCountries.United

NationsUniversity-EHS-WorkingPaper.Barrios,S.,Bertinelli,L.andStrobl,E.2006:Climaticchangeandrural–urbanmigration:Thecaseof sub-SaharanAfrica.

JournalofUrbanEconomics60,357-371.Henry, S., Boyle, P. and Lambin, E.F. 2003:Modelling inter-provincialmigration in Burkina Faso: the role of socio-

demographicandenvironmentalfactors.AppliedGeography23,115-136.Kniveton,D.,Schmidt-Verkerk,K.,Smith,C.andBlack,R.2008:ClimateChangeandMigration:ImprovingMethodologiesto

EstimateFlows.Geneva:InternationalOrganizationforMigration-MigrationResearchSeries33.Piguet,E.2008:Climatechangeandforcedmigration.NewIssuesinRefugeeResearch-UnitedNationsHighCommissioner

forRefugeesResearchPaper.

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Water temperature changes in receiving waters due to the increase of imperviousness: a multidisciplinary assessment approach

RossiLuca1,MargotJonas1,HariE.Renata2

1Ecole polytechnique fédérale de Lausanne (EPFL), Ecological Engineering Laboratory (ECOL), ENAC - IEE, Station 2, CH-1015 Lausanne (luca.rossi@epfl.ch)2 Swiss Federal Institute for Aquatic Science and Technology (EAWAG), Department of Systems Analysis, Integrated Assessment, and Modeling (SIAM), Überlandstrasse 133, CH-8600 Dübendorf

Watertemperatureisoneofthekeyparametersinfluencingthechemicalequilibriumanddevelopmentoffloraandfaunainaquaticsystems.Anincreaseintemperaturereducesoxygensolubility,acceleratesmetabolism,suchasphotosynthesisorthedevelopmentoffisheggs,andraisesthesensitivityoforganismstotoxicsubstances,parasitesanddiseases.Inurbanareas,anincreaseinwatertemperaturealsomayresultinanincreaseintoxicityfromammoniadischargingfromcombinedseweroverflows[(VSA2007).

Therearenumerouscausesoftemperaturechangesinreceivingwaters.Naturalcausescanincludeclimate(daily,seasonalandlong-termchanges)(Harietal.2006),thepresenceorabsenceofnear-streamshading,themorphologicalconditionsofthereceivingwatersorgroundwaterdischargeintotheaquaticsystem.Anthropogeniccausescanincludedischargefromhydro-electricpowerstationswithstoragelakes(suddenreservoirdrainagecausesasuddentemperaturedropintherecei-vingwater),dischargeofindustrialcoolingwater(whichusuallyheatsthereceivingwater),andurbanstormwaterdischargeduringarainevent(Rossi&Hari2007;Margot2008).Thisdischargeofurbanstormwaterduringraineventscanconstituteatemperatureproblemforreceivingwaters.Inurbanareas,thisthermalboostisrelatedtotheflowregime,thethermalandphysicalpropertiesofurbansurfacesandtheremovalofriparianvegetationalongurbanwatercourses.Thesefactorsincreasetheamountofthermalenergyinurbanreceivingwatersandmaylead,particularly insummer,toashort-termspikeinthereceivingwatertemperatureatthebeginningofarainevent.Infact,sealedasphaltsurfacesorroofscanreachextremelyhightemperatures(>60°C)duringextendedperiodsofgoodweather.Asimultaneouslylowwaterdischargerateinthereceivingwatersincreasesthepotentiallydangerousthermaleffectofthestormwaterdischargetoindigenousaquaticbiota.

Inthe1990s,analarmingdeclineinthecatchofbrowntrout(Salmo trutta fario L.)inriversandstreamsoccurredinWesternEurope,includingSwitzerland(Burkhardt-Holmetal.2002).Theclimatictemperatureincreaseisconsideredtobeoneofthemaindrivingforcesofthisdecline(Harietal.2006).Inadditiontoclimaticchange,theprogressiveincreaseintheareaofimpervioussurfaces(e.g.pavement)causedbyurbandevelopmentleadstostormwaterreachingaquaticsystemsmorerapid-ly,resultinginhigherin-streamtemperaturesthaninthepast.Swissanglerssuspectthaturbanstormwaterdischargeintoriversandstreamsduringraineventsmayharmthedevelopmentofcertainfishspecies.

Sincelegaltemperaturelimitsarecalculatedonlyoveralong-termdischargeperiod(≥year),theycannotbeappliedtoshort-termalterationssuchasthoseexpectedfollowingrainevents,thuscreatingalegalloophole.

Thisquestionwillbeaddressedwithinthispaper.Thresholdsareproposedforsensitivehabitatsduringaraineventasas-sessmentcriteriatoprotectthefishinthereceivingwatersfromthermalharm.Thethresholdsarebasedonthetemperaturerequirementsofbrowntrout,oneofthemostimportantfishnativetoSwissriversandstreams.Amultidisciplinaryassess-ment approach, including hydrological, physical, biological and ecotoxicological processeswill be presented and subse-quentlyvalidatedthroughthepresentationofdifferentcasestudiesofdifferentlysealedsurfacesinSwitzerland.

REFERENCESBurkhardt-Holm,P. Peter,A. Segner,H. 2002:Declineof fish catch in Switzerland - Project Fishnet:Abalancebetween

analysisandsynthesis.AquatSci64:36-54.Hari, RE. Livingstone,DM. Siber,R. Burkhardt-Holm, P.Güttinger,H. 2006:Consequences of climatic change forwater

temperatureandbrowntroutpopulationsinAlpineriversandstreams.GlobalChangeBiology12:10-26.Margot,J.2008:Impactsdesdéversoirsd’oragesurlescoursd’eau.ApplicationdelaméthodologieSTORMetvalidationpar

lebiaisd’analysesécotoxicologiquesetchimiques.MasterThesisEPFL,274pp+annexes.Rossi,L.Hari,RE.2007:Screeningproceduretoassesstheimpactofurbanstormwatertemperaturetopopulationsofbrown

troutinreceivingwater.IntegratedEnvironmentalAssessmentandManagementJournal3:383-392.VSA. 2007:Urbanwet-weather discharges in receivingwaters: guidelines for the conceptual planning of protection

measures(STORMguidelines,availableinFrench,GermanandItalian).SwissWaterPollutionControlAssociation,www.vsa.ch,Zürich,Switzerland.

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2008).InSwitzerland,onecriticaleventin5yearsistolerated(VSA2007).

5.9

Should climate models be evaluated with statistic-based or process-based metrics?

Schaller,Nathalie1,Mahlstein,Irina1&Knutti,Reto1

1 Institute for Atmospheric and Climate Science, ETH Zurich

Inthediscussiononthegreenhouse-inducedclimatechange,modificationsinthehydrologicalcycleareofparticularin-terestsincetheyareexpectedtohavesevereconsequencesforsocietiesandecosystems(IPCC,2007).Unfortunately,themo-delspreadforprecipitationislargeandprecisestatementsaboutfuturechangesintheprecipitationpatternsaredifficulttoprovide.Theevaluationofclimatemodelsisarelativelynewresearchfieldandthus,sofarnostandardizedmetricfordefiningaclimatemodel'sskillhasbeendefined.Recently,someattemptshavebeenmadetorankorweightthemodel'sprojections(Phillips&Gleckler,2006,Gleckleretal.,2008,Pincusetal.,2008).Thereby,thefavouredwaytoproceedwastoevaluatethemodelsimulationsagainstobservationsusingstatisticalmeasures.However,wesuspectthatdependingonthepurposeandthevariableconsidered,process-basedmetricsdefinedonaregionalscalearemoresuitabletoidentifythegoodmodelsthanstatisticalmeasuresdefinedonaglobalscale.Here,wecomparethreedifferentwaysofrankingtheclimatemodels,namelyastatistic-basedrankingconsideringabroadrangeofclimatevariablesperformedbyReichler&Kim(2008),astatistic-basedrankingconsideringonlytheprecipitationfieldandaprocess-basedrankingconsistingofsixmetricsrepresentingregionalfeaturesofthemodelledprecipitationresponsetoclimatechange.Surprisingly,themultimodelmeanperformsonlyaveragefortheprocess-basedranking,whileitoutperformsallsinglemodelsinthestatistics-basedrankings.Themodelsperformingbestcanbedifferentforeachregionorzoneconsideredandidentifyingthemeachtimenewlydependingontheapplicationmayallowformorereliableprojections.Further,consideringonlythefivebestmodelsforeachmetricallowsforareductionofthemodelspreadandthus,formorepreciseinformationaboutthefutureclimatestate.

REFERENCESGleckler,P.J.,K.E.Taylor,&C.Doutriaux,2008:Performancemetricsforclimatemodels.JournalOfGeophysicalResearch-

Atmospheres,113(D6),D06,104.IPCC(2007),Climatechange,2007:Thephysicalsciencebasis.ContributionofworkinggroupItothefourthassessmentreport

oftheIntergovernmentalPanelonClimateChange[Solomon,S.,D.Qin,M.Manning,Z.Chen,M.Marquis,K.B.Averyt,M.Tignor&H.L.Miller(eds)],CambridgeUniversityPress,Cambridge,UnitedKingdomandNewYork,NY,USA,p.996.

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ofmultimodelstatistics.WaterResourcesResearch,42(3).Pincus,R.,C.P.Batstone,R.J.P.Hofmann,K.E.Taylor,&P.J.Glecker,2008:Evaluatingthepresent-daysimulationofclouds,

precipitation,andradiationinclimatemodels.JournalOfGeophysicalResearch-Atmospheres,113(D14),D14,209.Reichler,T.&J.Kim,2008:Howwelldocoupledmodelssimulatetoday'sclimate?BulletinOfTheAmericanMeteorological

Society,80(3),303-311.

5.10

The MeteoSwiss strategy for the renewal of the precipitation measure-ment network

CatherineStocker-Mittaz,ChristianHäberli,ChristophFrei,UrsGermann1

1Federal Office of Meteorology and Climatology MeteoSwiss, Krähbühlstrasse 58, CH-8044 Zürich (catherine.stocker@meteoswiss.ch)

Therequirementsforprecipitationdatahaveriseninrecentyears:inparticular,meteorologists(eg,forthewarningofex-tremeevents)andhydrologists(eg,calculationofthearealprecipitationforfloodwarnings)aredependingonprecipitationinformationwithbothahighspatialandtemporalresolution.Asaresultoftheincreasinguseofprecipitationdatainfore-castmodels(runoffforecasting,snowpackdevelopment,agriculture,etc.)theneedforquantitativeprecipitationfieldshasincreased.Fortheseapplicationsahighabsoluteaccuracyandhighspatial/temporalresolutionisrequiredandthedataneedtobeavailableasfastaspossible.

TheconventionalprecipitationmonitoringnetworkofMeteoSwiss started inDecember1863.Precipitationamountsandsnowheightsaremeasuredmanuallyonceperday.Neitherthemethodofobservationnortheprocessingofthedatahavebeensubstantiallyadaptedtonewtechnologies.

Duetotheincreaseddemands,bothsomecantonsandprivateinstitutionsdesignedtheirownmeasurementnetworksandoperateapproximately300automaticprecipitationstationsinSwitzerland.Inaddition,thecantonsareincreasinglyinteres-tedinco-operationregardingdesignandoperationofmeasurementstationsandhandlingofdatawithMeteoSwiss.

InthecontextoftherollingrequirementsreviewthedifferentobservingsystemsandnetworksfromMeteoSwisswereinte-grallyconsideredandtheMeteoSwissstrategyfortherenewaloftheprecipitationmeasurementnetworkwasdeveloped.

Acomparisonofthevariousobservingsystems,precipitationanalysisandproductsshowsthestrengthsandweaknessesofthepossiblecombinationsofthedifferentmeasurementplatforms(automaticsurfacestations,conventionalprecipitationmeasurementnetwork,radar).Forapplicationswiththedemandsofahighspatialandtemporalresolutionandhighabso-luteaccuracynoneoftheproductsturnsoutasappropriate.

Requirementsforprecipitationinformationfromclimatology,meteorology,hydrologyandradartechnology,togetherwiththeresultingstrengthsandweaknessesofcurrentproducts,resultinastrategywithwhichthedeficienciesofthecurrentmonitoringnetworkshallbecountered:

• MeteoSwissprovidesspatiallycomprehensivedatasetswithhightemporalresolution(atleasthourly)thatallowstate-mentsabouttheprecipitationpatternsintheindividualregionsforwarningsinSwitzerland(138).

• MeteoSwissprovidesatleastinday-resolutiondatasetsthatallowstatementsabouttheprecipitationpatternsinareassmallerthantheregionsforwarnings.Theserecordshaveahigherabsoluteaccuracythantheoneswithhightemporalresolution.

• MeteoSwissprovideslongprecipitationdataseries(alsofortotalandfreshsnowheight)forstatisticalevaluationsandtakesthenecessarymeasurestosecurethesites,whichareimportantforthecomprehensivemonitoringofclimatologi-calprecipitationconditions(includingsnowheights)inSwitzerland.

• MeteoSwissoffersastandardizedproductportfolioinwhichtheserecordscanbeprovidedcustomer-oriented.

Approximately50additional,fullyequipped(notonlyprecipitation)surfacestations,100automaticandabout200conven-tionalprecipitationstationsresult(mostlyatsitesoftheexistingprecipitationmeasurementnetwork).ThenewstationswillbebuiltandoperatedbyMeteoSwiss.Forspecificneeds,thisnetworkshallbecompletedwithstationsofthefederalgovernmentand the cantons.Theseadditional stations shallbe certifiedand thus receivea status similar to stationsofMeteoSwiss(includingdatastorageintheMeteoSwissdatawarehouse).

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Lionel Cavin

Schweizerische Paläontologische Gesellschaft (SPG/SPS), Kommission der Schweizerischen Paläontologischen Abhandlungen (KSPA), Swiss Commission of Palaeontology Award

6.1 BeckerD.,BergerJ.-P.,HiardF.,Menkveld-GfellerU.,MennecartB.&ScherlerL.:LateAquitanianmammalsfromtheEngehaldelocality(Bern,Switzerland)

6.2 BrühwilerT.,BucherH.,GoudemandN.,WareD.,HermannE.:Smithianammonoids(EarlyTriassic):explosiveevolu-tionaryradiationfollowingthePermian/Triassicmassextinction

6.3 Buffetaut,E.:Darwiniandinosaurs:missinglinksorevolutionaryfailures?

6.4 GiraultF.E.&ThiersteinH.R.:DiatomassemblageturnoverintheNW-Pacificatthe2.73Maclimatetransition

6.5 GiraultF.E.,WellerA.F.&ThiersteinH.R.:Neogeneglobalcooling:diatomsizevariabilityinachangingocean

6.6 GoudemandN.,OrchardM.,TafforeauP.,UrdyS.,BrühwilerT.,BucherH.,BrayardA.,GalfettiT.,MonnetC.,LebrunR.&ZollikoferC.:PaleobiologyofEarlyTriassicconodonts:implicationsofnewlydiscoveredfusedclustersimagedbyX-raysynchrotronmicrotomography

6.7 Klug C., Kröger B., Kiessling W., Mullins G.L., Servais T., Frýda J., Korn D. & Turner S.: The Devonian NektonRevolution

6.8 KlugC.,SchulzH.&DeBaetsK.:RedtrilobiteswithgreeneyesfromtheDevonianofMorocco

6.9 KlugC.,SchweigertG.,FuchsD.&DietlG.:Firstrecordofabelemnitepreservedwithbeaks,armsandinksacfromtheNusplingenLithographicLimestone(Kimmeridgian,SWGermany)

6.10 LavoyerT.,BertrandY.&BergerJ.-P.:Theborehole01983X2854(Preuschdorf,UpperRhineGraben,Alsace,France)asabasisofaformaldefinitionoftheUpperPechelbronnBeds(Rupelian)

6.11 MenncartB.,BeckerD.&BergerJ.-P.:DeterminationofthepaleodietandthephylogenyofextinctruminantsusingRelativeWrapAnalysisonmandibles:caseofIberomeryxminor(Mammalia,Artiodactyla)

6.12 Monnet C., Hugo B., Guex J. & Wasmer M.: Macroevolutionary trends of Acrochordiceratidae Arthaber, 1911(Ammonoidea,MiddleTriassic)

6.13 RomanoC.&BrinkmannW.:Reinvestigationofthebasalray-finnedfishBirgeriastensioeifromtheMiddleTriassicofMonteSanGiorgio(Switzerland)andBesano(Italy)

6.14 Scherler,L.TütkenT.,BeckerD.&BergerJ.-P.:TerrestrialpalaeoclimaticalandpalaeoenvironmentalreconstructionsinNorthwesternSwitzerland:carbonandoxygenisotopecompositionsofEarlyOligoceneandLatePleistoceneverte-brateremains.

6.15 UrdyS.,GoudemandN.,BucherH.&MonnetC.:Howdorecurrentpatternsofcovariationinmolluscanshellsconnecttogrowthdynamics?

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Late Aquitanian mammals from the Engehalde locality (Bern, Switzerland)

DamienBecker1,Jean-PierreBerger2,FlorentHiard2,UrsulaMenkveld-Gfeller3,BastienMennecart2,&LaurelineScherler2,1

1Section d’archéologie et paléontologie, République et Canton du Jura, Office de la culture, Hôtel des Halles, Case postale 64, 2900 Porrentruy 2, Switzerland (damien.becker@palaeojura.ch)2Département de Géosciences, Géologie et Paléontologie, Université de Fribourg, Chemin du Musée 6, 1700 Fribourg, Switzerland3Natural History Museum Bern, Bernastrasse 15, 3005 Bern, Switzerland

DuetotheconstructionoftheSwissnationalroadfromBerntoWorblaufenin1850,thesandyandmarlydepositsoftheLower FreshwaterMolasse (USM)were excavated in Engehalde. Some specimens of vertebrate fossils (turtles, ruminants,suids,andrhinocerotids)andshellsofgastropodsandbivalveswerebroughttolightbyStuder(1850).ThenStehlin(1914)reportedthepresenceofPalaeochoerus typus,butthereferredmaterialwasnotfoundinthehistoricalcollectionanymore.Thesameauthornotifiedalsotworuminants,Amphitragulus cf. elegansandAmphitragulus lemanense.However,asthesetwotaxaareconsideredsynonyms,onlyAmphitragulus elegensisvalid.Moreover,manyspecimenswronglyascribedto Amphitragulus elegansorAmphitragulus lemanense intheliterature havetobereportedtothecloserspeciesDremotherium feignouxi.There-mainsofrhinocerotidswerereviewedbyBecker(2003)andascribedtoDiaceratherium lemanense:someofthemdisplayderivedmorphologicalcharactersinterpretedasprobableintraspecificvariations.ThesehistoricdiscoveriesallowafirstdatingtotheAquitaniantime.

DuringtheconstructionoftheNeufeldtunnel(2006–2008),theancientfossillocalityofEngehaldewasmadeaccessibleforarestrictedtime.TheNaturalHistoryMuseumBernorganizedanewpalaeontologicalexcavationcampaign.Thediscoveredma-terialdidnotcontainnewrhinocerotidremains,butyieldedessentiallyspecimensofrumiants,composedbyteethandpost-cranialbonesassigned to the“Dremotherium–like”group (probablyDremotherium feignouxi).The lower left jawofamustelid,probablyfromthegenusPalaeogale,Plesictis,orPlesiogale,wasthehighlightofthenewdiscoveries(Fig.1). Thewashingandpi-ckingof sedimentsamplesallowedthesortingofcharophytes fromthegroupStephanochara praeberdotensisaswellas smallmammalremainswithProlagus sp.,Eucricetodoninfralactorensis,Peridyromyssp.andCainotheriumsp.(Menkveld-Gfeller&Becker2008).

Figure1.Lowerleftjawofamustelid-likepredator(fossillength6cm)

Thesenewdata,inparticulartheoccurenceofProlagus sp.andEucricetodoninfralactorensis,allowanimproveddatingofthislocalitytothelateAquitanian(EuropeanMammalReferenceLevelMN2;BurkartEngesser,pers.com.).Thisbiostratigraphicalinterpretation coincides with other well-dated localities reporting similar faunal composition, like the derived form ofDiaceratherium lemanense (Becker et al. 2009) and the representatives of the Amphitragulus elegans – Dremotherium feignouxigroup(Gentryetal.1999).Regardingthepalaeosynecology,thereferredmammalassociationdoesnotpermitanaccuratecharacterization of the environment of the Bern area during the late Aquitanian. However, the representatives of theAmphitragulus elegans – Dremotherium feignouxigroupcouldpointtotheexistenceofawoodedenvironment.TheirassociationwithDiaceratherium lemanense underlinesprobablyabushlandinatransitionalzonebetweenforestandgrassland.Moreover,the lithofaciesof thetrappingsediments (fluvialsandsandfloodplainmarls) indicateanenvironmentprobablyclosetobodiesofwaterorswamps.

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Becker, D. 2003: Paléoécologie et paléoclimats de laMolasse du Jura (Oligo-Miocène): apport des Rhinocerotoidea(Mammalia)etdesminérauxargileux.PhDThesis,UniversityofFribourg,GeoFocus9,327pp.

Menkveld-Gfeller,U.&Becker,D.2008:BaustelleZubringerNeufeld:eineneuealteFossilfundstelle.BulletinfürangewandteGeologie13,107-112.

Becker,D.,Bürgin,T.,Oberli,U.&Scherler,L.2009:AjuvenileskullofDiaceratheriumlemanense(Rhinocerotidae)fromtheAquitanianofEschenbach(easternSwitzerland).NeuesJahrbuchfürGeologieundPaläontologieAbhandlungen254,5–39.

Gentry,A.W.,Rössner,G.E.&Heizmann,E.P.J.1999:SuborderRuminantia.In RössneR, G.e. & HeIssIG, K. (eds.): THe MIocene Land MaMMaLs of euRope. VeRLaG dR. fRIedRIcH pfeIL, MüncHen, 225–258.

Studer,B.1850:ÜberdieSüsswassermolassebeiBern.MitteilungenderNaturforschendenGesellschaftinBern178,89–92.

6.2

Smithian ammonoids (Early Triassic): explosive evolutionary radiation following the Permian/Triassic mass extinction1

BrühwilerThomas1,BucherHugo1,2,GoudemandNicolas1,WareDavid1,HermannElke1

1Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Strasse 4, 8006 Zürich (bruehwiler@pim.uzh.ch) 2Department of Earth Sciences, ETH, Universitätsstrasse 16, 8092 Zürich

In the aftermath of the end-Permianmass extinction, ammonoidswere among the fastest clades to recover: the recentanalysisofaglobaldiversitydatasetofammonoidgenerafromtheLateCarboniferoustotheLateTriassicshowsthatTriassicammonoidsactuallyreachedlevelsofdiversityhigherthaninthePermianlessthan2millionyearsafterthePTB(Brayardetal.,2009).TheevolutionofEarlyTriassicammonoidswasnotasmooth,norgradualprocess. It ischaracterizedbythefollowingmainfeatures:(i)averylowdiversityintheGriesbachian(earlyInduan),(ii)amoderatediversityincreaseintheDienerian(lateInduan),(iii)anexplosiveradiationintheearlySmithian(earlyOlenekian),(iv)alateSmithianextinctioneventfollowedbyasecondexplosiveradiationintheearlySpathian(lateOlenekian)(Brayardetal.,2006,2009).

InordertobetterunderstandtheSmithianammonoidradiationweconductedextensivefieldstudiesintwoclassicalregionsfortheEarlyTriassic,namelytheSaltRange(Pakistan)andSpiti (IndianHimalayas).Smithianammonoidsfromthesere-gionshavebeenknownformorethanacentury,andtheseplacesarethetypelocalitiesofmanytaxa(e.g.Waagen,1895;Krafft&Diener,1909).Additionally,westudiedasectionatTulong(SouthTibet)aswellasextremelyammonoid-richexoticblocksofHallstattLimestoneintheOmanMountains.

Ourabundant,bed-rock-controlledandwell-preservedmaterialenablesustorevisemanyclassicalammonoidtaxathatwerepreviouslyknownonlyinadequately.Moreover,alargenumberofnewtaxawasfound,whichenablesustodefineonenewfamily,18newgeneraandabout29newspecies.Atotalofeightsuccessiveammonoidassociationscanbecorrelatedbetweenoursections(Brühwileretal.,2007).Thishigh-resolutionbiochronologicalschemefortheSmithianoftheNorthernIndianMargincanbecorrelatedwithammonoidsuccessionsfromotherregionssuchasSouthChina(Brayard&Bucher,2008).

DuetotheveryhighevolutionaryratesofEarlyTriassicammonoids(Brayardetal.,2009)thereconstructionofphylogeneticrelationshipsamongSmithianammonoidsisdifficult.However,ourwell-constrainedtaxonomicandbiochronologicdataprovidenewinsightsontheevolutionofseverallineages.Furthermore,theongoingcomprehensivestudyofDienerianam-monoidfaunasfromtheSaltRangeandfromSpiti(Wareetal.)willhelpustodecifertheoriginofsomeSmithianammo-noids.

1ThisresearchissupportedbytheSwissNSFproject200020-113554.

REFERENCESBrayard,A.&Bucher,H. 2008: Smithian (Early Triassic) ammonoid faunas fromnorthwesternGuangxi (SouthChina):

taxonomyandbiochronology.FossilsandStrata,55,1-179.Brayard,A.,Bucher,H.,Escarguel,G., Fluteau,F.,Bourquin,S.&Galfetti,T.2006:TheEarlyTriassicammonoidrecovery:

Paleoclimaticsignificanceofdiversitygradients.Palaeogeography,Palaeoclimatology,Palaeoecology,239,374–395.Brayard,A.,Escarguel,G.,Bucher,H.,Monnet,C.,Brühwiler,T.,Goudemand,N.,Galfetti,T.&Guex,J.,2009:GoodGenesand

GoodLuck:AmmonoidDiversityandtheEnd-PermianMassExtinction.Science,325,1118-1121.Brühwiler,T.,Bucher,H.,Goudemand,N.&Brayard,A.2007:Smithian(EarlyTriassic)ammonoidfaunasoftheTethys:new

preliminaryresultsfromTibet,India,PakistanandOman.TheglobalTriassic:NewMexicoMuseumofNaturalHistoryandScienceBulletin,41.

Krafft,A.v.&Diener,C.,1909:LowerTriassiccephalopodafromSpiti,MallaJohar,andByans.PalaeontologiaIndica,ser.15,6,1-186.

Waagen,W.,1895:Salt-Rangefossils.Vol2:FossilsfromtheCeratiteFormation.PalaeontologiaIndica13,1-323.

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Darwinian dinosaurs : missing links or evolutionary failures ?

EricBuffetaut

CNRS, UMR 8538, Laboratoire de Géologie de l’Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris Cedex 05, France (eric.buffetaut@sfr.fr)

CharlesDarwindidnotoftenmentiondinosaursinhisworks.InthethirdeditionofOn the origin of species (1861,p.346),healludedtotheminachapteraboutextinction:“Solittleisthissubjectunderstood,thatIhaveheardsurpriserepeatedlyexpressedatsuchgreatmonstersastheMastodonandthemoreancientDinosaurianshavingbecomeextinct;asifmerebodilystrengthgavevictoryinthebattleoflife.Meresize,onthecontrary,wouldinsomecasesdeterminequickerextermi-nationfromthegreateramountofrequisitefood”.Tenyearslater,inThe descent of man, and selection in relation to sex(1871,p.204),heemphasizedtheirevolutionarysignificance:“Prof.Huxleyhasmadetheremarkablediscovery,confirmedbyMr.Copeandothers,thattheoldDinosauriansareintermediateinmanyimportantrespectsbetweencertainreptilesandcer-tainbirds—thelatterconsistingoftheostrich-tribe(itselfevidentlyawidely-diffusedremnantofalargergroup)andoftheArcheopteryx,thatstrangeSecondarybirdhavingalongtaillikethatofthelizard”.

ThusDarwinillustratedtwoviewsofdinosaursthatweretobecomebothprevalentandcompetinguntiltoday:iconsofex-tinction,ormissinglinks.The“missinglink”interpretationpredominatedduringthelastpartofthe19thcenturyandthebeginningofthe20th,whendinosaurswerewidelyconsideredasancestraltobirds,onthebasisofosteologicalresemblanceandthediscoveryofbothArchaeopteryxandthe“toothedbirds”,HesperornisandIchthyornis,fromtheLateCretaceousoftheUnitedStates.Accordingtothisview,dinosaurs,asbirdancestors,hadplayedanimportantpartintheevolutionofoneofthemost successful groupsof living vertebrates. This interpretation fell outof favourduring themid-twentieth century,largelybecauseoftheinfluentialbookbyGerhardHeilmann,The origin of birds (1926), inwhichthepurportedabsenceofclaviclesindinosaurswasusedtodemonstratethattheycouldnotpossiblyhavebeenancestraltobirds(whichpossessclavi-cles)–since“Dollo’slaw”stipulatesthatonceanorganhasbeenlostinthecourseofevolution,itcannotreappearagain.

Asdinosaurscouldnolongerbeseenasancestraltoanything,theyhadtobeconsideredassomekindofevolutionarydeadend,andthisinterpretationprevaileduntilthe1970s.Theimageofthedinosaursastoolarge,tooslowandtoostupidtohavebeenabletosurvivebecameprevalentforalargepartofthe20thcentury.Thiscouldbeseenintermsofnaturalselec-tion,withlargefoodrequirementsasapossibledisadvantage,asalreadymentionedbyDarwinin1861,orintermsofnon-Darwinian,orthogeneticevolutionresultinginnon-adaptivetransformationsdetrimentaltotheorganismsinvolved.Theideathatdinosaursweresomehow“doomed”toextinctionbyratherobscureevolutionarymechanismsbecamepopularforalongtime.

Thingschangedagaininthe1970swhendinosaurbiologywasthoroughlyreinterpretedandtheimageofsluggish,cold-blooded giantswas challenged and a new view of dinosaurs asmore active, possiblywarm-blooded, animals graduallyemerged.Thiswenttogetherwithareappraisalofdinosaur-birdrelationships,basedonnewdiscoveriesofsmallcarnivo-rousdinosaursanddescriptionsofnewspecimensofArchaeopteryx,whichresultedinarebirthofthehypothesisofthedi-nosaurian ancestry of birds. This was strengthened by the discovery of clavicles in many dinosaurs (thus eliminatingHeilmann’sobjection)andbythatofthefamous“feathereddinosaurs”fromtheEarlyCretaceousofChina,whichprovideextremelystrongevidenceinfavourofaclosephylogeneticrelationshipbetweensmalltheropoddinosaursandbirds.

Inthe1980s, thequestionofdinosaurextinctionalsounderwentarevival,withinthe larger frameworkofcatastrophiceventsattheCretaceous-Tertiaryboundary.Thediscoveryofthemajorasteroidimpactthathappened65millionyearsagoledtoathoroughreconsiderationofthepossiblecausesofterminalCretaceousextinctions, includingthatofnon-aviandinosaurs.Seenaspartofmajorextinctioneventaffectingmanygroupsoforganismsinvariousenvironments,inalllike-lihoodcausedbytheimpactofanextra-terrestrialobject,thedisappearanceofthedinosaurscouldnolongerbeseenastheresultofsomemysteriousinabilitytoadapttogradualenvironmentalchange.AlthoughthedetailsofdinosaurextinctionattheendoftheCretaceousremaintobeworkedout,thereasonfortheirdisappearanceisnowmuchclearerthanitwasbeforethediscoveryoftheend-Cretaceousimpact–andDarwin’soriginalremarkabouttheimportanceoffoodresources(orthelackthereof)takesonanewsignificanceinviewofcurrenthypothesesaboutthecollapseoffoodwebsfollowingtheasteroidimpact.

Althoughtheevolutionarysignificanceofdinosaurs,bothintermsofextinctionandofintermediateforms,wasapparenttoDarwin,andtoquiteafewofhisfollowers,includingHuxley,inthe19thcentury,itwasunderratedduringmuchofthe20thcentury.Itisonlysincethe1990sthatpalaeontologistshaverecognisedagainthatdinosaurswerenotsimplyanextinctgroupofreptiles,butwereinfactthesourceofoneofthemajorgroupsoflivingvertebrates,viz.thebirds,andthatthedemiseofnon-aviandinosaurswastheresultofanexceptionalglobalevent,ratherthantheconsequenceofsomekindofnon-adaptiveevolution.Theexampleofdinosaursillustrateswellhowtheoutdatedconceptof“evolutionaryfailures”hasbeensupersededbyamoretrulyDarwinianinterpretationofthefossilrecord.

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gy REFERENCES

Darwin,C.1861:On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life.3rdedition.JohnMurray,London.

Darwin,C.1871:The descent of man, and selection in relation to sex.JohnMurray,London.Heilmann,G.1926:The origin of birds.Witherby,London.

6.4

Diatom assemblage turnover in the NW-Pacific at the 2.73 Ma climate transition

GiraultFranceE.&ThiersteinHansR.

Geological Institute, ETH, Sonneggstrasse 5, CH-8092, Zurich (france.girault@erdw.ethz.ch)

TheNorthPacificcontainsacriticaldiatomsedimentaryrecordoftheCenozoicglobalcoolinghistory.ThemoststrikingpartofthatrecordcoverstheultimateclosureofthePanamaSeaway2.73MaagowhichwassynchronouswiththeonsetofNorthernHemisphereglaciations(NHG).Thesephysicalchangeswereconcomitantwithanabruptchangeinthebiologicalpumpefficiencyrelatedtotheonsetofoceansurfacewaterstratification.TheODPsite882record(Leg145)-withitswellconstrainedNeogenepaleoceanographichistoryaroundthe2.73Matransi-tion-providesanexcellentbasistotestpatternsandpotentialcontrolsofdiatomsizevariabilityandspeciesdominance.Frustulesizesofcentricdiatomshavebeenquantifiedtobetterunderstandtheenvironmentalresponseoftheseorganismstoadrasticandpermanentpaleoceanographicandclimaticchange.Sizeandmorphologicalcharacteristicsofthecentricdiatomfrustules (diameter>20µm)werecollectedforastatisticallyrepresentativenumberofspecimens(i.e.250-700)persampleusingrecentlydevelopedautomatedlightmicroscopyandim-ageanalysistechniques.

6.5

Neogene global cooling: diatom size variability in a changing ocean

GiraultFranceE.1,WellerAndrewF.1,2&ThiersteinHansR.

1 Geological Institute, ETH, Sonneggstrasse 5, CH-8092, Zurich (france.girault@erdw.ethz.ch)2 Present address: Geosoft Australia Pty Ltd, 14/100 Railway Road, Subiaco WA 6008, Australia

Overthepast40Ma,thedevelopmentandstepwiseexpansionoftheAntarcticice-sheet,togetherwithtectonicmovements(e.g.closureofthePanamaisthmus)havedeeplymodifiedthepatternsofglobalcirculationandchemicalsignatureofthevariouswatermasses(e.g.redistributionofdissolvedsilica).Thesechangeshavealsoinducedthedevelopmentofoceanicboundaries(e.g.Polarfront),directlyaffectingtheevolutionofplankticmicro-organisms.Usingthewidespreadrecordof siliceousmicrofossils (SouthernOcean,EquatorialPacificandNorthPacific),wehaveas-sessedtheimpactsoftheseoceanographicreorganizationsondiatoms,focusingonsizeandtaxonomicchangesandturno-versamongcentricdiatomsoverthepast15Ma.TheabilityofdiatomstoadaptandsurviveinachangingoceanhasprobablybeenakeyfortheirsurvivalespeciallyovertheNeogene,whenclimaticandoceanographicchangeshavebeenthestrongest.Similarly,sizevariabilityamongthisgrouptightlyreflectstheirresponsetoenvironmentalperturbationsaswellastheirtaxonomicturnoversthathavebeendrivingdiatomevolutionarypatternstowardhighlydiverseandendemiccommunitiesprevailingintoday’soceans.

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Paleobiology of Early Triassic conodonts: implications of newly discove-red fused clusters imaged by X-ray synchrotron microtomography

GoudemandNicolas1,OrchardMichael2,TafforeauPaul3,UrdySéverine1,BrühwilerThomas1,BucherHugo1,BrayardArnaud§,GalfettiThomas1,MonnetClaude1,LebrunRenaud§§&ZollikoferChristoph§§

1Paläontologisches Institut und Museum, Universität Zurich, Karl Schmid-Str. 4, 8006 Zürich (goudemand@pim.uzh.ch). 2Geological Survey of Canada, 101-605 Robson St., Vancouver,BC, V6B 5J3 Canada.3European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38043 Grenoble cedex, France. §UMR-CNRS 5561 Biogéosciences, Université de Bourgogne, 6 Bd Gabriel, 21000 Dijon, France.§§Anthropologisches Institut und Museum, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich

SeveralfusedclustersofconodontelementsoftheEarlyTriassicgenusNovispathodus werediscoveredinlimestonebedsattheSmithian-Spathianboundary(LuolouFormation.,Galfettiet al.,2008)fromseverallocalitieswithintheGuangxiprovinceof South China. Conodont clusters are groups ofmorphologically different elements belonging to the same individual,whichweresomehowcementedtogetherpost-mortem.SuchspecimensofexceptionalpreservationareextremelyrareintheTriassicandthesearethefirstreportedfortheEarlyTriassic.Ourfusedclusterspartiallypreservetherelativethree-dimensionalpositionandorientationofsomeramiform,graspingelements.Theyarethereforeextremelyimportantforourunderstandingofthefeedingapparatusesofconodonts.Becauseoftheintricategeometryofthesuperposedelements,oftheirfragilityandoftheirextremerarity,itisusuallytrickytostudysuchspecimens.Weovercometheseproblemsbyperformingapropagationphasecontrastsynchrotronmicrotom-ography(Tafforeauet al.,2006).Apinkbeamsetupat17.6keV,whichwasveryrecentlydevelopedattheEuropeanSynchrotronRadiationFacilityonbeamlineID19,hasbeensuccessfullytestedonourconodonts.Thisnewtechniqueenablesasubmicronresolution(0.23µm)withaspeedandanoverallqualityneverreachedbefore.Somefusedclustersaswellasco-occurringisolatedelementsfromthesamesampleandpertainingtothesamemulti-elementspecieswerescannedusingthistech-nique.BesidestaxonomicrevisionoftheGondolelloideasuperfamily(themostsignificantgroupofconodontsduringPermianandTriassictimes),thisdiscoveryledustoproposeanewfunctionalmodel.Inourview,thebestsolutionimpliesthepresenceofapresumablycartilaginous‘copula’,uponwhichtheconodontele-mentsaremovingindependently,moreorlessasdodentalplatesinextantlampreys,butnotstrictlyasproposedbyPurnellandDonoghue (1997).Wesuggest thatduringretractiontowards thecaudally locatedplatform (cuttingorgrinding)ele-ments,theS0elementfirsthasaclosing,rotatingmovement,mostprobablysynchronizedwiththeclosureoftheMele-ments,withwhichitwouldhaveperformedapinching,seizingfunction.Thismovementisthenfollowedbyasub-straight,dorso-caudallydirectedtranslation,bywhichitwouldhavetornofftheprey’s‘flesh’andbroughtittowardstheplatformelements.ThelattermovementisaccompaniedbytheclosureoftheotherSelements,channellingthefoodintheappropri-atedirection.Consideringthatthepresenceofsuch‘copula’associatedwithtongueprotractorandretractormuscleshasbeenassertedonlyforextantcyclostomes(hagfishesandlampreys;Yalden,1985;Donoghueet al.,2000),ournewmodelmayprovideim-portantinsightsfordecipheringtheaffinityofconodontsandforourgeneralunderstandingoftheoriginofvertebrates.

AcknowledgementsThisresearchissupportedbytheSwissNSFproject200020-113554.WeacknowledgetheEuropeanSynchrotronRadiationforprovisionofsynchrotronradiationfacilitiesandforgrantingaccesstobeamlineID19.

Figure1.Animated3dreconstructionofthefeedingapparatusofNovispathodus.

REFERENCESGalfetti,T.,Bucher,H.,Martini,R.,Hochuli,P.A.,Weissert,H.,Crasquin-Soleau,S.,Brayard,A.,Goudemand,N.,Brühwiler,

T.&Guodun,Kuang2008. Evolutionof Early Triassic outerplatformpaleoenvironments in theNanpangjiangBasin

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gy (SouthChina)andtheirsignificanceforthebioticrecovery.Sed.Geol.204:36-60.

Tafforeau, P., et al. 2006. Applications of X-ray synchrotronmicrotomography for non-destructive 3d studies ofpaleontologicalspecimens.Appl.Phys.A83:195-202.

Purnell,M.A.&Donoghue,P.C.J.1997.ArchitectureandfunctionalmorphologyoftheskeletalapparatusofOzarkodinidconodonts.Phil.Trans.R.Soc.Lond.B352:1545-64.

Yalden,D.W.1985.Feedingmechanismsasevidenceofcyclostomemonophyly.Zool.J.Linn.Soc.84:291-300.Donoghue,P.C.J.,Forey,P.L.&Aldridge,R.J.2000.Conodontaffinityandchordatephylogeny.Biol.Rev.75:191-251.

6.7

The Devonian Nekton Revolution

Christian Klug1, Björn Kröger2, Wolfgang Kiessling2, Gary L. Mullins3, Thomas Servais4, Jiří Frýda5, Dieter Korn2 & Sue Turner6

1Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid-Strasse 4, CH-8006 Zürich, Switzerland, (chklug@pim.uzh.ch) 2Museum für Naturkunde, Humboldt-Universität zu Berlin, Invalidenstraße 43, D-10115 Berlin, Germany3Department of Geology, The University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom4Laboratoire de Paléontologie et Paléogéographie du Paléozoïque, UMR 8014 du CNRS, Université des Sciences et Technologies de Lille, SN5 Cité Scientifique, F-59655 Villeneuve d’Ascq, France5Faculty of Environmental Science, Czech University of Life Sciences, Kamýcká 129, 165 21 Praha 6 Suchdol, Czech Republic6Queensland Museum, 122 Gerler Rd., Hendra, Queensland 4011, Australia

ImpressivediscoveriesofNeoproterozoicandEarlyPalaeozoicFossillagerstaettendrewtheattentiononevolutionaryandecologicalprocessesofthesetimespans.Italmostseemedthat,exceptforsomeofthe“BigFive”,nothingessentialhappenedaftertheOrdovician.Suchascenarioiscertainlynottrue.

Contrariwise,somemajorecologicalfluctuationshavebeenrecordedfromtheDevonian,severalofwhichhavelesspromi-nentSilurianprecursors.Famousexamplesaretheradiationoflandplantsandjawedfish(bothknownalreadyfromthepre-Devonian).DuringtheDevonian,severalanimalgroupsconqueredtheland(variousarthropodsandpossiblytetrapods).Marineinvertebratesshowsignificantecologicalandmorphologicalchanges:Importantcephalopodgroupssuchasbactri-toidsaswellasammonoidsevolvedandreefgrowthincreaseduntiltheLateDevoniancrises.Boththeglobalriseandfallofdacryoconaridsoccurred,graptolitesbecameextinct,andvariousmollusccladesmodifiedearlyontogeneticstrategiesdur-ingtheDevonian,documentingaplanktonicturnover.Inaddition,thereisamacroecologicalchangeinmarinefaunasfromademersal(swimmingclosetothesea-floor)andplanktonichabittowardsamoreactivenektonichabit.

VariousinterpretationsareathandtoexplainthisDevonianNektonRevolution: (1)Demersalandnektonicmodesoflifewereprobablyinitiallydrivenbycompetitioninthediversity-saturatedbenthichabitatsaswellas(2)theavailabilityofrichplanktonicfoodresources(asreflectedinevolutionaryalterationsinearlyontogeneticstagesofmanymollusks).Escalatoryfeedbacksprobablypromotedtherapidevolutionofnekton(jawedfishandsomederivedcephalopodgroupsinparticular)intheDevonian,assuggestedbythesequenceandtempoofwater-columnoccupation.Potentially,boththeseradiationsandtheGivetiantoFamennianmass-extinctionswerelinkedtoapronouncedincreaseinnutrientinputtoseasurfacewatersduringeutrophicationepisodes.

6.8

Red trilobites with green eyes from the Devonian of Morocco

ChristianKlug1,HartmutSchulz2andKennethDeBaets1

1Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Str. 4, CH-8006 Zürich (chklug@pim.uzh.ch)2Institut für Geowissenschaften, Eberhard-Karls-Universität Tübingen, Sigwartstr. 10, D-72076 Tübingen, Germany

Latest Emsian (Early Devonian) sediments at the famous mud-mound- and trilobite-locality Hamar Laghdad (Tafilalt,Morocco)yieldedsomewellpreserved,largelyred-colouredremainsofphacopidtrilobites.Closerexaminationrevealedthatonlythelensesoftheeyesofthesephacopidsareusuallygreenishincolour.EDX-analysesshowedthatthelensesretainedtheiroriginalcalciticcompositionwhilemostoftheexoskeletonwassilicified.Thesilicifiedpartscontainelevatedconcen-trationsofironwhichcausestheredcolour.

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yPresumably,theprimaryporosityofmostofthephacopidexoskeletonexceptthechitinouslegsandthelenseswas,becauseoftheporecanals,higherthanthatofthelenses,facilitatingthereplacementofcalcitebyotherminerals.Furthermore,thepresenceoforganiccomponentsinthelensesincombinationwithahomogeneousdistributionofthecalcitecrystalsmighthaveslightlyincreasedtheresistanceofthelensestowardsmineralreplacement.Thehomogeneityofthecalcitecrystalsofthelenseswasneededfortheiroptimalopticalfunctionality.Thesefactorsprobablyaccountforthefactthattheeyesreta-ined the calcitewhich is oftengreenish inbrachiopod shells suchas the thick-shelledMiddleDevonianDevonogypa andIvdeliniafromtheMaïderBasinwhiletherestofthetrilobiteexoskeletonisred.Thisdifferentialreplacementalsoexplainswhythelensesareslightlycorrodedwhiletherestoftheexoskeletonissuperficiallywellpreserved.Sofar,thisdifferentialreplacementofcalciteisonlyknownfromtheeyesofphacopids.Othertrilobitetaxafromthesamestrataandlocalityhaveholochroaleyesandthusmuchsmallerlenseswhichwereprobablymorerapidlyreplacedbysilica.Thegreenishcolourofthe lensesmightoriginatefromimpuritiesof ironandmagnesium;theconcentrationsofthecorrespondingionsmighthavebeentoolowtobedetectedwiththeEDXwithcertainty.

HamarLaghdadalsoyieldedphacopidexoskeletonswith lesscompletelysilicifiedexoskeletonswhichenabledadetailedreconstructionofthesilicificationprocess.Initially,onlytheoutersurfaceoftheexoskeletonandthevicinityofporecanalsweresilicified.Inasecondstep,thebendinthegrowthlinesoftheinterlensarscleraweresilicifiedtogetherwiththere-mainingexoskeletonexceptforthelenses,thenthecompleteinterlensarscleraandintheendalsothelenses.

6.9

First record of a belemnite preserved with beaks, arms and ink sac from the Nusplingen Lithographic Limestone (Kimmeridgian, SW Germany)

ChristianKlug1,GünterSchweigert2,DirkFuchs3andGerdDietl2

1Paläontologisches Institut und Museum, Karl Schmid-Str. 4, CH-8006 Zürich (chklug@pim.uzh.pim)2Staatliches Museum für Naturkunde, Rosenstein 1, D-70191 Stuttgart, Germany3Institut für Geowissenschaften, Freie Universität Berlin, Malteserstr. 74-100, D-12249 Berlin, Germany

A recent discovery of anunusually preserved belemnite fromNusplingen comprises the extraordinarily rare remains ofbeaksandnearly in situ arm-hooksaswellas the ink sacand the incompletephragmocone.So far,Hibolithes semisulcatus(Münster, 1830) is the only larger belemnite known from the Nusplingen Lithographic Limestone (Upper Jurassic, LateKimmeridgian,BeckeriZone,UlmenseSubzone;SWGermany)whichhasthesamephragmoconeshapeandsize,thusweassignthenewspecimentothistaxon.Therostrumwasprobablylostduetoalethalpredationattemptinwhichthepreywaskilledbutnotentirelyeaten.Forthefirsttime,aspecimenrevealsdetailsofthebelemnitebeakmorphology,whichwecomparetothebeaksofotherJurassiccephalopods.Thisspecimenpresentlyrepresentstheonlyknownrostrum-bearingbelemniteofpost-Toarcianagewhichhasbeenpreservedwithnon-mineralisedbodyparts.AsHibolithes semisulcatus isknowntopossessonepairofmega-onychites,theabsenceofthoseinthepresentspecimenprovidesevidenceofsexualdimorphisminHibolithes semisulcatus. Thisphenomenonwaspreviouslypresumedforallbelemnites,butitisknownonlyfromPassaloteuthiswithcertaintysince therostrumofthelatterisunambiguouslyassociatedwithanarmcrownthatoccasionallyincludesonepairofmega-onychites.TheimperfectpreservationofthebelemnitebeakshampersadetailedcomparisonwithotherRecentandfossilcoleoidbeaks.Somemorphologicalcharacters(lowwidthoftheouterlamella,doublelaterallobesofthedarkpartsofrostrumandhood,possiblyshortinternallamella)ofthelowerbeakofHibolithes morecloselyresembleRecentde-capodsthanRecentoctopods.TheupperbeakofHibolithes differsinthelong,narrowandcurvedrostrumfromthosecoleoidbeakspreviouslyknownfromNusplingen.Thedarkpartofthelowerbeakalsoshowsauniqueoutlinewithashortandpointedrostrum,anelongateposteroventralextensionandtwosmall roundedsinuseswhichpointedtowards thewings(sometimes similarlydeveloped inRecentSepioteuthis). It appears likely that this beak form is quite characteristic and itmightreflectaspecialdietofthebelemnites.Takingtheirprobablyhighswimmingvelocity(fins,stream-linedbody,andhorizontal orientationof the longest body axis)with the armhooks and the sharpbeaks into account, it appearsquitelikely that belemniteswere fast-swimming, effective,medium-sized predators.With the newdiscovery,NusplingennowrepresentstheonlylocalitywhichhasyieldedcompletebeakapparatusesfromallmajorJurassiccephalopodgroups.

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The borehole 01983X2854 (Preuschdorf, Upper Rhine Graben, Alsace, France) as a basis of a formal definition of the Upper Pechelbronn Beds (Rupelian)

LavoyerThibault,YerlyBertrand&BergerJean-Pierre

Département de Géosciences, Géologie et Paléontologie, Université de Fribourg, chemin du Musée 6, 1700 Fribourg, Switzerland

FromthemiddleEocenetoLateOligocene,anintenselacustrine,brackishandmarinesedimentation,documentedbysaltdepos-itsandoilaccumulation,tookplaceintheUpperRhineGraben(URG),especiallyinthePechelbronnBeds(Lower-,Middle-andUpper).

Althoughtheselayerswerestudied,inthepast,fortheoilindustry(Schnaebele1948)andarealithostratigraphicunitusedinmapsandpapersconcerningthePaleogeneoftheURG,theyhaveneverbeenformallydesignatedbecausetheyalmostnevercropoutat thesurfaceanddriftinganddrillingmaterialswereoftendiscarded.Nevertheless, the InternationalStratigraphicGuide(seeMurphyandSalvador1999),demandsatypesectionforeachformallynamedFormation.

SeveralpalaeogeographicalreconstitutionsandstratigraphicchartsfortheURGhavebeenpublished(Bergeretal.2005a&b).However,theRupeliandepositswerenotwelldefined.

ThisworkpresentsthefirststepforadefinitionofatypesectionofatypesectionoftheUpperPechelbronnBeds,withthepresentationofseverallithofaciesandpaleontologicaldata.

Thestudiedborehole,01983X2854(Preuschdorf,Alsace,France)isacompletecoreddrilling,about220mindepth.Itwasoriginallymadetoevaluateadecontaminationissue,buthasalsoyieldedmicropaleontologicalandsedimentologicaldata.ItcorrespondstotheUpperPechelbronnBedswithasmallpartoftheMiddlePechelbronnBedsatthebase.

Thehighabundanceofostracodsandgastropodsingreymarls,correspondingtothe10lowermeters,indicatethetopoftheMiddlePechelbronnBedswiththeHydrobiaZone.Theselayersarecoveredbyasuccessionofmarlsandsandstone,suggest-ingadifferentenvironment.ThelowerpartoftheboreholeisconsistentwiththelithostratigraphiczonationdefinedbySchnaebele(1948)forhis“normalfacies”whereastheupperpartcorrespondstohis“freshwaterfacies”.

The lower part of the borehole has yielded new paleontological data. Diatoms (Triceratium sp), charophytes (Chara spp.,Rhabdocharasp.), foraminifers (Ammodiscussp.,Quinqueloculinasp.,Flintinasp.,Lenticulinaspp.,Dentalinasp.,Subreophax elon-gates, Vaginulopsis spp.), bivalves, gastropods, bryozoans, ostracods (Grinioneis tribeli, Hazelina indigena, Hemicyprideis spp.,Ilyocyprissp.),insects,echinoderms,fishesandmammalsteethareusedasmainindicatorsofbiostratigraphyandpalaeoecol-ogy.Thefossilrecordemphasizesacomplexalternationoffreshwater,brackishandmarinefaunaalongthewholestudiedsection.

This study is financedby theSNFProject200020-118025 “PaleontologyandStratigraphyof theRhinegrabenduring thePaleogene”,andincludespartsoftheMasters-thesisofB.Yerly“ThetransitionbetweentheMiddleandUpperPechelbronnBedsinthedrilling1983X2854,Preuschdorf(Rupelian,UpperRhineGraben,Alsace,France)”(inprep.2009)andthePhD-thesisofT.Lavoyer“PaleontologyandStratigraphyoftheMiddleUpperRhineGrabenduringthePaleogene:akey-studyfortherelationshipsbetweenRiftsystem,AlpineOrogenyandPaleoclimate”(inprogress).

We thank S. Spezzaferri (Uni. Fr., foraminifers), C. Pirkenseer (Uni. Leuven, ostracods) for fossils determination, P. Elsass(BRGM)andM.Kimmel(Geoderis)forprovidingaccesstothecoredrilling.

REFERENCESBerger,J.-P.etal.,2005a.PaleogeographyoftheUpperRhineGraben(URG)andtheSwissMolasseBasin(SMB)fromEoceneto

Pliocene.InternationalJournalofEarthSciences,94(4):697-710.BergerJ.-P.etal.,2005b.Eocene-PliocenetimescaleandstratigraphyoftheUpperRhineGraben(URG)andtheSwissMolasse

Basin(SMB).InternationalJournalofEarthSciences,94(4):711-731.MurphyM.A.&SalvadorA.1999.InternationalStratigraphicGuideAnabridgedversion.Episodes,Vol.22,no.4SchnaebeleR., 1948.Monographiegéologiquedu champpétrolifèredePechelbronn. –MémoiresduServicede laCarte

géologiqued’AlsaceetdeLorraine,7:254SStrasbourg

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Determination of the paleodiet and the phylogeny of extinct ruminants using Relative Wrap Analysis on mandibles: case of Iberomeryx minor (Mammalia, Artiodactyla)

BastienMennecart1,DamienBecker2&Jean-PierreBerger1

1Department of Geosciences – Earth Sciences, ch. du Musée 6, Pérolles, 1700 Fribourg, Switzerland (bastien.mennecart@unifr.ch)2Section d’archéologie et paléontologie, République et Canton du Jura, Office de la culture, Hôtel des Halles, Case postale 64, 2900 Porrentruy 2, Switzerland

TheprimitiveruminantIberomeryxisessentiallyknownbyfewdentalremainsandisstillpoorlydocumented.Itsphylogenyandpalaeobiologystaysratherenigmatic.Onlytwospecieshavebeendescribed:thetypespeciesI. parvusfromtheBenaralocalityinGeorgia(Gabounia1966),andtheWestEuropeanspeciesI. minorfromItardies,Mounayne,RaynalandRoqueprune2inQuercy (Sudre1987),MontalbaninSpain(Golpe-Posse1974),andLovagny,Soulceand BeuchilleintheSwissMolasseBasin(Beckeretal.2004).I. savageifromIndiahadrecentlybeenplacedinthenewgenusNalameryx (Métaisetal.2009).AlltheselocalitiesaredatedtotheRupelianandcorrespondmainlytoMP23(Europeanmammalbiozone).Basedontheshorttooth-crownheightandthebunoselenodontpatternofthemolars,Sudre(1984)andBeckeretal.(2004)proposedafolivore/frugivoredietforIberomeryx.

Basedonrelativewarpanalysis(24landmarks)of84extantandfossilruminantmandiblesfrom24generaand32species,thisstudyproposesapreliminarydiscussiononthephylogenyandthedietofthegenusIberomeryx.TheresultspermittodifferentiatePecoraandTragulinaonthefirstaxisthankstothelengthofthediastema,thelengthofthepremolarsandthemandibleankle.AssuggestedbySudre(1984),IberomeryxisclosetotheextantTragulinabytheshapeofitsmandible.But,thislatterisclearlydifferentofthoseoftheTragulidae,theonlyextantfamilyinTragulina.Thisdifferenceisessentiallyduetoastockiermandible (condylarprocess,mandibleramusandcorpus mandibulae),andadeepermandibularincisure.Additionally,weobservenodiastemaandwellbunodontteeth.IberomeryxmaybeconsideredasaprimitiveTragulidae,theonlyknownfromtheOligocene,basedonthegeneralshapeofitsmandibleanditsjawteeth.Moreover,itsdietcouldnotbestrictlyfrugivore,butitcouldpossiblyalsoexceptionallyeatsomemeatmattersuchassmallHypertragulidae.

ThisstudyissupportedbytheSectiond'archéologieetpaléontologie(Porrentruy),theUniversityofFribourg,andtheSwissNationalFoundationproject(115995)onthelargemammalevolutionintheSwissMolasseBasinduringtheOligoceneandEarlyMiocene.

REFERENCESBecker,D.,Lapaire,F.,Picot,L.,Engesser,B.&Berger,J.-P.2004:Biostratigraphieetpaléoécologiedugisementàvertébrésde

LaBeuchille(Oligocène,Jura,Suisse).RevuedePaléobiologie,Vol.spéc.9,179-191.Gabounia,L.1966:SurlesMammifèresoligocènesduCaucase.BulletindelaSociétéGéologiquedeFrance7,857-869.Golpe-Posse,J.1974:FaunasdeYacimientosconSuiformesenelTerciarioespanol.PublicacionesdesInstitutoProvincialde

PaleontologiadeSabadell,PaleontologiayEvolucion8,1-87.Métais,G.,Welcomme, J.-L-&Ducrocq, S. 2009:New lophiomericyd ruminants from theOligocene of theBugtiHills

(Balochistan,Pakistan).JournalofVertebratePaleontology29(1),231-241.Sudre, J. 1984:CryptomeryxSchlosser, 1886, tragulidéde l'Oligocèned'Europe; relationsdugenre et considérations sur

l'originederuminants.Palaeovertebrata14,1-31.

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Macroevolutionary trends of Acrochordiceratidae Arthaber, 1911 (Ammonoidea, Middle Triassic)

MonnetClaude1,BucherHugo1,GuexJean2&WasmerMartin1

1Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid Strasse 4, CH-8006 Zürich (claude.monnet@pim.uzh.ch, hugo.fr.bucher@pim.uzh.ch, martin.wasmer@gmail.com)2Institut de Géologie et Paléontologie, Université de Lausanne, BFSH-2, CH-1015 Lausanne (jean.guex@unil.ch)

Directedevolutionoflifethroughmillionsofyears,suchasincreasingcomplexityandincreasingadultbodysize,isoneofthemostintriguingpatternsdisplayedbyfossillineages.ThegeneraltendencyforbodysizetoincreaseduringtheevolutionofagroupofanimalsisknownasCope’srule.Processesandcausesofsuchmacroevolutionarytrendsremainhowevertobeclearlyunderstood (Jablonski2000).Amongfossils,ammonoidshells (marinecephalopods)arewellknowntoexperiencerepetitivemacroevolutionarytrendsoftheiradultsize,geometryandornamentation(Schindewolf1940;Haas1942;Bayer&McGhee1984;Dommergues1990;Guex1992).

ThisstudyanalyzestheevolutionarytrendsofthefamilyAcrochordiceratidaeArthaber,1911,whichspannedtheupperEarlytolowerMiddleTriassic.ExceptionallylargecollectionsofthisammonoidfamilyfromNorthAmericaenablequantitativeand statistical analyses of its macroevolutionary trends. This study highlights that (1) the monophyletic clade ofAcrochordiceratidaefollowstheclassicalevolutetoinvoluteevolutionarytrend(i.e.increasingcoilingoftheshell);(2)thelineagealsoshowsaseeminglystepwiseincreaseofitsshelladultsize(shelldiameter);(3)thecladealsorecordsincreasingcomplexityofitssutureline;and(4)thelineageisalsocharacterizedbyaprominentincreaseoftheintraspecificvariationofitsshellmorphology,whichfollowstheBuckman’sLawofCovariation.

Thesemacroevolutionarytrendsarestatisticallyrobustandseemmoreorlessgradual.Furthermore,theycanbeconsideredasnon-randomwiththesustainedshiftofthemean,theminimumandthemaximumofstudiedshellcharacters.Suchre-sultisusuallyinterpretedasbeingtheeffectofaselectionpressureontheentirelineage,whichleadstoinferthepresenceofoneecologicalnichecommontoallspeciesofthismostlyanageneticlineagewithmoderateevolutionaryrates.

Increasinginvolutionofammonitesisusuallyinterpretedbyincreasingadaptationmostlyintermsofimprovinghydrody-namics.However,thistrendinammonoidgeometrycanbeexplainedasacaseofCope’srule(increasingadultbodysize)insteadofad hocfunctionalexplanationsofcoiling,becausebothshelldiameterandshellinvolutionaretwopossiblepathsforammonoidstoaccommodateincreasingbodysize.

REFERENCESBayer,U.&McGhee,G.R.1984:IterativeevolutionofMiddleJurassicammonitefaunas.Lethaia,17,1-16.Dommergues,J.L.1990.Ammonoids.In:McNamara,K.J.(ed.),Evolutionarytrends,BelhavenPress,London,162-187.Guex,J.1992:Originedessautsévolutifschezlesammonites.BulletindelaSociétéVaudoisedeSciencesNaturelles,82,117-

144.Haas,O.1942:RecurrenceofmorphologictypesandevolutionarycyclesinMesozoicammonites. JournalofPaleontology,

16,643-650.Jablonski,D.2000.Micro-andmacroevolution:scaleandhierarchyinevolutionarybiologyandpaleobiology.Paleobiology,

26(suppl.4),15-52.Schindewolf,O.H.1940.KonvergenzbeiKorallenundAmmoniten.FortschrittederGeologieundPalaeontologie,12,387-491.

Figure.EvolutionarytrendsrepresentedbylateimmatureshellgeometryandsuturelineforAcrochordiceratidaeduringtheAnisian

(MiddleTriassic).GlobalevolutionarytrendsaffectingsuccessivespectraofvariantsforAcrochordiceratidaeareincreasingadultshellsize,

increasinginvolution,increasingsuturecomplexity,andincreasingintraspecificvariability.(NextPage)

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6.13

Reinvestigation of the basal ray-finned fish Birgeria stensioei from the Middle Triassic of Monte San Giorgio (Switzerland) and Besano (Italy)

RomanoCarlo1&BrinkmannWinand1

1Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, CH-8006 Zürich (carlo.romano@pim.uzh.ch; wbrink@pim.uzh.ch)

ThetwoearlierdescriptionsandapreviousreconstructionoftheMiddleTriassicactinopterygianBirgeria stensioeiaLdInGeR,1931fromtheBesanoFormationofMonteSanGiorgio(CantonTicino,Switzerland)andBesano(Lombardy,Italy)reliedeit-heronafewfragmentaryremainsoronasingleindividualonly.HerewepresentthefirststudyofB. stensioeithatisbasedonmultiplespecimensofthisbasalray-finnedfish.Sixty-sevenspecimenshavebeenexamined.

ThereinvestigationofB. stensioeiyieldednewinformationatgenusandspecieslevel.B. stensioeipredominantlydiffersfromtheotherspeciesofthegenusBirgeriasTensIö,1919inthearrangementofthebonesofthedorsalfinbase.Whileintheotherspeciesusuallytwoseriesofpterygiophoresarepresentthroughoutthedorsalfinbase,onlyoneseriesofpterygiophoresisdevelopedintheanteriorpartofthedorsalfinrootofB. stensioei.ThecaudalpeduncleandthecaudalfinlobesaremoreslenderandlongerthanillustratedinthepreviousreconstructionofB. stensioei(seescHwaRz1970).ThemorphologyofthecaudalpeduncleandfinaswellastheaforementionedspecialiseddorsalfinrootindicatethatpropulsionmighthavebeenmoreadvancedinB. stensioeicomparedtotheotherspeciesofthegenusBirgeria.B. stensioei isfurthermoredistinguishedfrommostoftheotherspeciesofBirgeriabythedegreeofossificationofthebraincaseandthepalatoquadrate.Asinmanyotherbasalactinopterygians,adermohyalisdevelopedinB. stensioeiandthisboneisprobablypresentintheotherspeciesofBirgeriaaswell.

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Terrestrial palaeoclimatical and palaeoenvironmental reconstructions in Northwestern Switzerland: carbon and oxygen isotope compositions of Early Oligocene and Late Pleistocene vertebrate remains.

ScherlerLaureline1,2,TütkenThomas3,BeckerDamien2&BergerJean-Pierre1

1Department of Geosciences, Institute of Geology, ch. du Musée 6, CH-1700 Fribourg (laureline.scherler@unifr.ch)2Section d'archéologie et paléontologie, Hôtel des Halles, CP64, CH-2900 Porrentruy3Steinmann Institute, University of Bonn, Poppelsdorfer Schloss, D-53113 Bonn

VertebrateremainsfromtwoEarlyOligocenelocalitiesoftheDelémontbasin (BeuchilleandPoillat)andfromeightLatePleistocenedolinefillingsoftheAjoieRegion(Courtedoux-VâTcheTchâandBoncourt-Grand'Combe)havebeenexcavatedalongtheTransjuranehighway(CantonJura,NorthwesternSwitzerland).Teethoflargemammalsandbonesofaquaticrep-tileshavebeenanalysedfortheirisotopecompositions(δ18O

CO3,δ18O

PO4,δ13C)inordertoreconstructthepalaeoclimaticaland

palaeoenvironmentalconditions.

ThetwoEarlyOligocenelocalitiesofBeuchilleandPoillatarelocatedintheJuraMolasse("Molassealsacienne"Formation)of the Delémont basin (Northern Switzerland). The presence of the smallmammal Blainvillimys avus and the ruminantIberomeryx minorallowsadatationtothemammalzonesMP23-24,around31.5to29.0Ma(Beckeretal.2004).Eightsamplesofreptilebones(crocodilesandturtles)aswellasfoursamplesofsympatricprimitiverhinocerotidteeth(Ronzotheriumsp.)havebeenanalysed.Thereptileboneshave lowδ18O

PO4values (from13.6‰to17.8‰) indicatingfreshwaterenvironments

(δ18OH2O

calculatedvaluesaveraging-6.15±1.03‰)whicharesupportedbythepalaeontologicalidentificationsoftheturtleremains(TrionyxandTestudinidae:freshwaterandterrestrialturtles,respectively).Asimilarδ18O

H2Ovalueof -6.18±1.5‰is

calculatedfromenamelδ18OPO4

values(18.3±1.3‰)oftherhinocerotidteeth,whichpresumablyreflectsthecompositionofmeteoricwater.Usingamodern-daymeanairtemperature(MAT)-δ18O

H2OrelationforSwitzerlandaMATof18.0±2.5°Cforthe

EarlyOligocenecouldbecalculatedandwasabout8-9°CwarmerthantodayintheCantonJura(RecentMATof8.7°C).Thisresultisinagreementwiththepalaeotemperatureof~17°CreconstructedfromfossilplantremainsintheEarlyOligoceneofCentralEuropebyMosbruggeretal.(2005).

TheeightLatePleistocenedolinefillingsofBoncourt-Grand'Combe(GC)andCourtedoux-VâTcheTchâ(VTA)arelocatedintheAjoieRegion(NorthwesternSwitzerland)andcorrespondmainlytoloessicandgraveldepositsassociatedwithfossilre-mains.Forty-sixteethoflargemammals(Equus germanicus, Mammuthus primigenius, Coelodonta antiquitatis, Bison priscus)havebeenanalysed:eightsamplesfromtheGCdolinefillingandthirty-eightfromthesevenVTAdolinefillings.Thesedimenta-ry series bearing the mammal remains trapped within the GC doline have been dated by OSL (Optically StimulatedLuminescence)toanageof~80kaBP.ThemammalremainspreservedwithinthesevenVTAdolineshaveallbeendiscoveredinthesamesedimentaryunitdatedtothetimeinterval45-40to35kaBP(latestMiddlePleniglacial)byOSLandradiocarbon(Beckeretal.2009).

Accordingtotheenamelδ13Cvalues,whicharesimilarinbothtimeperiods,thelargemammalslivedinaC3plant-domina-

tedenvironmentasindicatedbyvaluesrangingfrom-14.5‰to-9.2‰(O'Leary,1981).TheMATcalculatedfromtheδ18OPO4

valuesofthelargemammalassemblagefromtheGCdolineaverages6.0±4.6°C.TheMATcalculatedforthelargemammalassemblageoftheyoungerVTAdolinesaverages5.6±4.1°C,showingaquitesimilarclimate.Thislatterresultisconcordingwiththequantifiedecologystudyofthesmallmammalassemblagesofthesedolines,whichindicatespalaeotemperaturesaveraging 5°C (Oppliger, 2009). These palaeoclimatical values are about 3 to 4°C cooler than today in theCanton Jura.However,somevariationsintheδ18O

PO4valuesofthedifferentstudiedspeciesareobserved,andparticularlyintheVTAdo-

lines:forexampletheequidsshowslightlylowerδ18OPO4

values(13.09±0.8‰)thanthebovids(14.6±1.1‰).ThecalculatedMATafterspecificcalibrationscanthusbeverydifferent,rangingfrom2.2±2.8°CfortheEquusremainsto8.8±3.5°CfortheBisonremains,withavalueof5.8±3.3°CfortheCoelodontaand8.7±2.2°CfortheMammuthus.

Inordertounderstandthisbiasaprecisedsamplingofteethformedbeforeandaftertheweaningofthefoalshasbeendone.Itshowsthattheoxygenisotopiccompositionsarenotaffectedbythenursingperiodwhereasthecarbonisotopesshowslightlylowervalues.ThedifferencesinoxygenstableisotopecompositionswithintheseLatePleistocenemammalscouldthenbeenexplainedbythesamplingmethod,themammalphysiologyand/orecology,ortimeaveraging.ThedeterminationofapalaeotemperatureshouldbemorereliableduringtheOligocenewhentheclimatewasmuchmorestablethaninthePleistocenewhenbrutalclimaticalchangesoccurredveryfrequently.

WethanktheSectiond'archéologieetpaléontologieduJura,theUniversityofFribourgandtheSwissNationalFoundation(project115995)forfinancialsupport.

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LaBeuchille(Oligocène,Jura,Suisse).RevuedePaléobiologie,9,179-191.Becker,D.,Aubry,D.&Detrey,J.2009:LesdolinesduPléistocènesupérieurdelacombede"VâTcheTchâ"(Ajoie,Suisse):un

piègeàrestesdemammifèresetartéfactslithiques.Quaternaire,20,2,135-148.Mosbrugger,V.,Utescher,T.andDilcher,D.L.2005:CenozoiccontinentalclimaticevolutionofCentralEurope.PNAS,102,

14964-14969.O'Leary,M.H.1981:Carbonisotopesinphotosynthesis.BioScience,38,328-336.Oppliger, J. 2009: LamicrofaunedesdolinesduPléistocène supérieurde la combedeVâTcheTchâ etde la régionde

Boncourt(Ajoie,Jura,Suisse).Unpublishedreport,29pp.

6.15

How do recurrent patterns of covariation in molluscan shells connect to growth dynamics?

UrdySéverine1,GoudemandNicolas1,BucherHugo1andMonnetClaude1

1Paläontologisches Institut und Museum, Universität Zurich, Karl Schmid-Str. 4, 8006 Zürich (urdy@pim.uzh.ch).

Thecomparisonofshellshapeamongandwithindifferentcladesofmolluscscanbeinformativewithregardstothebasicrulesofaccretionarygrowth. Indeed,patternsofvariationofshell shapeand itsassociatedgrowthfeatures (likegrowthhalts)inammonoidsandgastropodssuggestthatcommonrulesofaccretionarygrowthunderliethemorphogenesisoftheshellanditsevolutioninbothclades(e.g.Bucher,1997;Checa&Jimenez-Jimenez,1997;Checaetal.2002).Moreover,insomephylogeneticallydistantammonoidsspecies,covariationsamongtheintensityofornamentation,thela-teralcompressionoftheapertureandthedegreeofwhorloverlaphavebeendescribed(Buckman’slaws).Ithasbeensugge-sted that simple growth rules could underlie these evolutionary recurrent patterns of covariation (Hammer & Bucher,2005a).Similarly,shellcharacterscovarywiththespacingbetweengrowthhaltsduringtheontogenyofsomeofthesehigh-lyvariableammonoidsspecies.Onegoalofthisstudyistoexplorewhetheracomparablepatternofcovariationistobefoundingastropodsaswell.Wealsowanttofindoutwhetherdocumentationofmodesofgrowthingastropodscouldsupporttheviewaccordingtowhichsomerecurrentpatternsofcovariationcouldreflectbasicconstraintstiedtoaccretionarygrowth.Anotherinterestistherelati-onshipamongshape,growthratesandage,apointthatisdifficult,ifnotimpossibletostudyonammonoids.Inthisstudy,weinvestigatetheontogeneticpatternsofcovariationamongapertureshape,intensityofornamentationandspacingbetweengrowthhaltsinapopulationofgastropods(Hexaplex trunculus,Muricidae)rearedundercontrolledlabora-toryconditions.Allindividualsoriginatedfromasingleeggmass.Wedescribethegrowthdynamicsoftheseindividualsfromtheageofapproximately100daysto550daysafterhatching.Thisstudyhighlightsacovariationamonggrowthrhythm,growthhaltsspacing,apertureallometryandintensityoforna-mentation:-Variationinshellshapeisanalysedbygeometricmorphometricsoflandmarkslocatedontheaperture.Wedocumentanontogeneticallometryofaperture,whichbecomesrelativelywiderwithsize.ThisisconsistentwithresultsobtainedusingellipticFourieranalysisofaperturecontourandtraditionalbiometrics.-Variationinthe‘strengthofornamentation’isrelatedtothemeanspacingbetweengrowthhalts:smoothersnailstendtoexhibitmorecloselyspacedgrowthhalts.Thiscovariation,asputinevidencehereinH. trunculus,seemsanalogoustothatobservedinsomehighlyvariableammonoidsspecies(e.g.Gymnotoceras rotelliformis,Amaltheus margaritatus).-Themeannumberofgrowthhaltspermonthisrelatedtotheglobalshapeofthegrowthcurveandtothemeanspacingbetweengrowthhalts:themorefrequentthegrowth‘pulses’,theshorterthetimespentonagrowthhalt(downtonearlycontinuousgrowth), themore linear thegrowthcurveandthesmaller thegrowthsegmentsbetweensuccessivegrowthhalts.Additionally,wedevelopagrowthvectormodel(Urdyetal.,2009)inordertosimulatetheformationofgrowthhaltspheno-menologically(Fig.1).Thismodelisabletoaccountforsomepatternsofcovariationamongspecimens.Inparticular,varia-tioningrowthrhythmisregardedascriticalingeneratingtheobservedcovariationbetweengrowthhaltsspacingandor-namentation.Basedonthesesimulations,wesuggestthatthiscovariationmainlyresultsfromsimplescalingamongtheaperturedimensionsandthelengthsofshellsegmentsbetweensuccessivegrowthhalts.Then,theimportantstructurationof phenotypic variation in some ammonoids species could be a generic outcome of underlying variation in growthrhythm.

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Figure1:Exampleofasimulationofgrowthhalts.

REFERENCESBucher,H.1997:Caractèrespériodiquesetmodedecroissancedesammonites:comparaisonaveclesgastéropodes.Geobios

MémoireSpécial,20,85-99.Checa,A.G.&Jimenez-Jimenez,A.P.1997:Regulationofspiralgrowthinplanorbidgastropods.Lethaia30(4),257-269.Checa,A.G.,Okamoto, T.&Keupp,H. 2002:Abnormalities asnatural experiments: amorphogeneticmodel for coiling

regulationinplanispiralammonites.Paleobiology28(1),127-138.Hammer,O.&Bucher,H.2005a:Buckman'sfirstlawofcovariation:acaseofproportionality.Lethaia38,67-72.Urdy, S.,Goudemand,N., Bucher,H.&Chirat, R. 2009:Allometries and themorphogenesis of themolluscan shell: a

quantitativeandtheoreticalmodel.JournalofExperimentalZoology,PartB(accepted).

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g 7. Future horizons in marine and continental research drillingFlavio Anselmetti, Othmar Müntener, Daniel Ariztegui

Commission of Oceanography and Limnology (COL)

7.1 Anselmetti F.S., Ariztegui D., Hodell D., Brenner M., Gilli A., Mueller A. & the PISDP scientific team members:Exploring200’000yearsofclimateandenvironmentalhistorywithICDPdrillcoresfromLagoPeténItzá,NorthernGuatemala

7.2 EfimenkoN.,BuchsD.,BuretC.,KawabataK.,SchleicherA.,UnderwoodM.,ArakiE.,ByrneT.,McNeillL.,SafferD.,TakahashiK.,EguchiN.,ToczkoS.&theExpedition319Scientists:Potentialandlimitsofdrillcuttingsforlithostra-tigraphical interpretations in siliciclastic environments: preliminary results from the IODPNanTroSEIZE Stage 2Expedition319SiteC0009(NankaiTrough,KumanoForearcBasin,Japan).

7.3 Früh-GreenG.,DelacourA.,BoschiC. :Lithosphericheterogeneities,hydrothermalactivityandserpentinizationatslowspreadingridges:Insightsthroughoceandrilling

7.4 Ildefonse,B.:Scientificdrillingintheoceanlithosphere:what’snext?

7.5 Preusser,F.:TheageofsedimentaryfillingsofoverdeependvalleysintheAlps

7.6 RecasensC.,ArizteguiD.,MaidanaN.I.,AnselmettiF.S.,VuilleminA.,FarahR.&thePASADOScientificTeam:NewsightsonLatePleistoceneclimatevariabilityinSouthernmostPatagonia:AnICDPapproach

7.7 Stockhecke M., Anselmetti F.S., Meydan A.F., Hammer P., Kipfer R., Odermatt D., Sturm M., Tomonaga Y. & thePALEOVANscientificteam:PALEOVAN-TheInternationalContinentalScientificDrillingProgram(ICDP)inLakeVan,EasternAnatolia(Turkey)

7.8 StrasserM.,MooreG.F.,AshiJ.,CamerlenghiA.,DuganB.,HuhnK.,KanamatsuT.,KawamuraK.,McAdooB.G.,PanieriG.,PiniG.-A.,UrgelesR.:AddressingGeohazardsfromSubmarineSlidesthroughOceanDrilling:The“NankaiTroughSubmarineLandslideHistory”drillingProposal

7.9 StraubM.,HaugG.,DanielS.,HaojiaR.:EvidenceforamiddlePliocenechangeintheoceannitrateinventorybasedonforaminifera-boundx15NintheCaribbeanSea

7.10 VuilleminA.,ArizteguiD.,PawlowskiJ.,TemplerS.&thePASADOScientificTeam:NewprospectsinICDPresearch:investigatingthesubsurfacebiosphereinLakePotrok-Aikesediments

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Exploring 200'000 years of climate and environmental history with ICDP drill cores from Lago Petén Itzá, Northern Guatemala

AnselmettiFlavioS.1,ArizteguiDaniel2,HodellDavid3,BrennerMark4,GilliAdrian5,MuellerAndreas5&PISDPscientificteammembers

1Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland (f lavio.anselmetti@eawag.ch)2Section of Earth & Environmental Sciences, University of Geneva, Switzerland3Department of Earth Science, University of Cambridge, UK4LUECI, University of Florida, Gainesville, Florida, USA5ETH, Swiss Federal Institute of Science and Technology, Zurich, Switzerland

AspartofarecentICDPinitiative,morethan1.3kmoflakesedimentwererecoveredatsevensitesofvaryingwaterdepthsinLagoPeténItzá,northernGuatemala.Multipleholeswithamaximumdepthof133mweredrilledateachcoresiteusingtheGLAD800drill-rigmountedontheRV/KerryKeltssuperbarge.Thisensuredcompleterecoveryof lacustrinesedimentsequencesthatcontainalong,continuousrecordofcontinentalclimatechangefromthelowlandNeotropics.Radiocarbonandtephrochronologicdatingindicatesthattherecordspansthelast~200kyr,permittingtostudythelong-termtropicalhydrologicandtemperaturechangesaswellasthecorrelationtootherregionalandglobalpaleoclimaterecords.

LakePeténItzáisthedeepestlakeinthelowlandsofCentralAmerica,withamaximumdepth>160m.Itishydrologically“closed,”makingithighlysensitivetopastchangesintheratioofevaporationtoprecipitation.Pre-drillingseismicsurveysandthenewdrillcoresconfirmthatthelakesedimentsaresensitiverecordersofpasthydrologicchangesasreflectedbyvariationsinlithologyandphysicalproperties.

SitePI-6(waterdepth=71m)wasdrilledtoamaximumsedimentdepthof75.9m.Radiocarbondatesonterrestrialorganicmatterarewellorderedandindicateameansedimentationrateof~1mm/yrto~44kyrBPatadepthof~49m.Theageofthebasal section isconstrainedbyan identifiedash layerat70.4m,1.5metersabove limestonebedrock.TheelementalgeochemicalfingerprintofthisrhyolitictephralayerisconsistentwiththeLosChocoyoseruptionoftheAtitlánCalderaaround84kyrBP.Thisageofthetephralayerresultsinasedimentationrateof0.6mm/yrforthelowersectionandchrono-logicallyconfinesatransgressionalsequence,whichrepresentstheonsetoflacustrinesedimentationinthebasinatthissite.AtSitePI-6,thetop10.8mweredepositedduringtheHoloceneandconsistprimarilyofgraycarbonateclaywithabun-dantcharcoal.ThePleistocene/HoloceneboundaryismarkedbyatransitiontoHoloceneclayfromunderlying,interbedded,densegypsumsandandclaydepositedduringtheLateGlacial(~17to9.3kyr).Thistransitionrepresentsaswitchfromrela-tivelyaridconditionsduringtheLateGlacialtomoisterclimateduringtheearlyHolocene.IncontrasttotheLateGlacialperiod,theLastGlacialMaximum(LGM),from23to17kyr,consistsofgraycarbonateclaythatissimilartoHolocenedepos-its,suggestinghighdetritalinputandhighlakelevel,i.e.moistconditions.ThisfindingcontradictspreviousresultsthatsuggestedtheLGMwasdryintheGuatemalanlowlands.InLakePeténItzá,claydepositionduringtheLGMwasprecededbyinterbeddedgypsumandgraycarbonateclaydepositedbefore~23kyrduringMarineIsotopeStage3.Thispatternofclay–gypsum(wet–dry)oscillationscloselyresemblesthetemperaturerecordsfromGreenlandicecoresandNorthAtlanticma-rinesedimentcoresandprecipitationproxiesfromtheCariacoBasin.ThemostaridperiodscoincidedwithHeinrichEventswhencoldseasurfacetemperaturesprevailedintheNorthAtlantic,meridionaloverturningcirculationwasreduced,andthe IntertropicalConvergenceZone (ITCZ)wasdisplacedsouthward.SedimentsdepositedduringMIS4and5aconsistoffine-grainedclay-richlithologieswithvariablecontentofcarbonateandorganicmatterreflectingrathermoistconditions.

Thebasal~85kyrhorizonwaspenetratedintwodrillsites,whereadeeperandolderstratigraphicsuccessionwasrecovered.Tephrastratigraphicanalysisdocumentthatthisolderlacustrinesuccessiondatesbackto~200kyrs,providingthusanun-precedentedlongpaleoclimatic/paleoenvironmentalrecordoftheCentralAmericantropics

REFERENCESHodell,D.A.,Anselmetti, F.S.,Ariztegui,D., Brenner,M.,Curtis, J.H., Escobar, J.Gilli,A.,Grzesik,D.A.,Guilderson, T.J.,

Kutterolf,S.andMüller.A.D.,2008,An85-karecordofclimatechangeinlowlandCentralAmerica:QuaternaryScienceReviews27,1152-1165.

Mueller, A.D., Anselmetti, F.S., Ariztegui,D.A., Brenner,M.,Hodell,D.A., Curtis, J.H., Escobar, J.,Gilli. A.,Grzesik,D.,Guilderson,T.P.,Kutterolf,S.,Plotze,M.L.,subm.,LateQuaternarypaleoenvironmentofNorthernGuatemala:evidencefromdeepdrillcoresandseismicstratigraphyofLakePeténItzá:subm.toSedimentology.

Mueller,A.D.,Islebe,G.A.,Hillesheim,M.B.,Grzesik,D.A.,Anselmetti,F.S.,Ariztegui,D.,Brenner,M.,Curtis,J.,Hodell,D.,Venz,K.A.,2009,ClimatedryingandassociatedforestdeclineinthelowlandsofnorthernGuatemaladuringthelateHolocene:QuaternaryResearch71,133-141.

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g 7.2

Potential and limits of drill cuttings for lithostratigraphical interpreta-tions in siliciclastic environments: preliminary results from the IODP NanTroSEIZE Stage 2 Expedition 319 Site C0009 (Nankai Trough, Kumano Forearc Basin, Japan).

N.Efimenko1,D.Buchs2,C.Buret3,K.Kawabata4,A.Schleicher5,M.Underwood6,E.Araki7,T.Byrne8,L.McNeill9,D.Saffer10,K.Takahashi11,N.Eguchi11,S.Toczko11andExpedition319Scientists12

1Institut de Géologie et Paléontologie, Université de Lausanne, Switzerland e-mail: natalia.efimenko@unil.ch2Research School of Earth Sciences, Australian National University3Université de Picardie Jules Verne, 80025 Amiens, France4National Central University, Taiwan5Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan, USA.6Department of Geological Sciences, University of Missouri, Columbia, Missouri 652117Earthquake and Tsunami Research Project for Disaster Prevention, JAMSTEC, Japan8University of Connecticut, Storrs, CT 06269, USA9University of Southampton, Southampton, UK10Dept. of Geosciences, Pennsylvania State University, USA11Centre for Deep Earth Exploration, JAMSTEC, Japan12D.Boutt, University of Massachusetts-Amherst, Amherst, USA; M.Conin, CEREGE, Collège de France, France; D.Cukur, Pukyong National University, Korea; M.-L.Doan, Université Joseph Fourier, France; P.Flemings, University of Texas, Austin, USA; K.Horiguchi, Osaka University, Japan; N.Hayman, University of Texas, Austin, USA; G.Huftile, Queensland University, Australia; T.Ito, Tohoku University, Japan; S.Jiang, Florida State University, USA; K.Kameo, Chiba University, Japan; Y.Kano, Kyoto University, Japan; G.Kimura, University of Tokyo, Japan; M.Kinoshita, JAMSTEC, Japan; K.Kitada, JAMSTEC, Japan; A.J.Kopf, University of Bremen, Germany; W.Lin, JAMSTEC, Japan; M.Kyaw Thu, JAMSTEC, Japan; C.Moore, University of California, Santa Crus, USA; G.Moore, University of Hawaii, USA; Y.Sanada, JAMSTEC, Japan; H.Tobin, University of Wisconsin-Madison, USA; K.Toshiya, JAMSTEC, Japan; G.Wheat, Monterey Bay Aquarium Research Institute, USA; T.Wiersberg, GFZ German Research Center for Geosciences, Germany

DuringtheIODPNanTroSeizeExpedition319riser-drillingsystemwasemployedforthefirsttimetocollectcuttingsandcoreforscientificpurposesatSiteC0009A(NankaiTrough,Kumanoforearcbasin).Cuttingsarethemixtureofrockfrag-mentsandsedimentsproducedas thedrillbit cuts throughthe formation.Duringriserdrilling, thecuttingsare trans-portedviathecirculationofdrillmudwithsuspendedcuttingsmaterialwithinriserpipebetweenthedrillshipandthebottomofthehole.Wepresentfirstgeologicresultsfromriserdrilling,coring,andcuttingscollectionattheSiteC0009AintheKumanoforearcbasin.OneofthescientificobjectivesforthissitewastocharacterisethelithologyanddeformationoftheKumanoforearcbasinsedimentsandunderlyingunits throughanalysisand integrationof (i) cuttings, (ii) core, (iii)measurementswhiledrilling,and(iv)wirelineloggingdata.Cuttingswereretrievedfromeach5mintervalsfrom703.9to1604mbelowseafloorandcoreswererecoveredfrom1509.7to1593.9mbelowseafloor.Ascoreavailabilitywasstronglylimitedbyoperationalcostsandtimerestrictions,thestudyofcuttingswasimportantfortheunderstandingoftheirpotentialandlimitsforlithos-tratigraphicalinterpretationscomparedtothecore.First,cuttingsweredescribedbasedonvisualmacroscopicdescriptionof thebulkmaterial.Weestimated (i) therelativeamountofcoarser(sand/silt)andfiner(clay)material,(ii)theappearance,relativeamountandsizeofhardrockchips,and(iii)theabundanceofwoodfragments.Then,weseparatedthegrainsofthesizemorethan45μmbysievinginordertodescribethemunderthebinocularmicroscopeandpreparesmearslides.Wedistinguishedspecificminerals,volcanicglassandlithicfragments,madequalitativeestimationsoftheirrelativeabundance,roundness,sorting,andrelativevariationingrainsize.Thechipsofhardrockof1-4mmsizewereseparatedandusedforthepreparationofthin-sections,X-raydiffrac-tionandX-rayfluorescenceanalyses.Wealsocomparedcuttingsandcoresinthecoredintervaltodeterminepossiblearti-factsanduncertaintiesrelatedtotheuseofcuttingsforlithostratigraphicalinterpretations.Cuttingsallowedustorecognisemajor lithologicalvariationsandtrends inmineralogicalandchemicaldata.Wedistin-guishedfourlithologicalunitscomposedofmudandmudstonewithcoarsersiltyandsandyinterbeds,andvolcanicash/tuff.Basedontheintegrationofcuttingsdescription,measurementswhiledrilling,wirelineloggingdata,seismicdataandbios-tratigraphy,firstthreelithologicalunitsareinterpretedasfine-grainedturbidite-richdepositsoftheKumanoBasinaccumu-latedduringPleistocenetoPresent.ThelowerpartofUnitIII(SubunitIIIB)hadanincreasedamountofwoodfragmentsandofroundedglauconite.Thisfactpointstotheincreasedterrigeneousinputintransgressionalsettings.TheSubunitIIIBisrepresentedbythefirstsedimentsdepositedabovetheangularuniconformitywithslightlyolderdepositsofUnitIVofLateMioceneage.Thedepthoftheunconformityis1285mbsf.TheUnitIViscomposedofthin-beddedturbiditeswhicharemorefine-grainedthanoverlyingdeposits.Compositionalmaturityofsedimentsisincreasedcomparedtothefirstthreeunits.ThisUnitcouldbeinterpretedeitherasaccretedtrenchsediments,orastrenchslopedepositsorassedimentsdepositedin

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ingthedistalreachesoftheearlyKumanoBasin.

Consistencybetweenunitboundariesdeterminedfromcuttingsandthosedeterminedfromlogdataisgoodintermsofdepth,withtypicalmismatchesoflessthan10m.Thelithologicalfuturesandvariationsatthescalesmallerthan5mcouldnotberecognised.Problemsaffectingthepreservationofcuttingsare(i)degreeoflithification,(ii)mixingofcuttings/cav-ings,and(iii)possiblecontaminationwithdrill-mud.Smallsizeofcuttings(<2cm)anddesegregationofpoorlylithifiedsedimentsduringthetransportinthedrillingmudmakesdifficulttoobtaintheinformationaboutlithofaciesandsedi-mentarystructures.Mineralogicalandchemicalanalysesincuttingsarebiasedbythepreferentialconsolidationoffine-grainedsedimentswithrespecttocoarse-grainedsediments.XRDandXRFanalysesfromcuttingsaremorehomogeneousthanthosefromcoresamples,andthecompositionofcuttingsissimilartothesamplesofsiltyclaystonesfromthecores.Inthefuture,moreaccuratequantitativecharacterisationofcuttingsthroughtheuseofdigitalimagingcanimprovethedescriptionoflithofacies.Althoughthequalityofcuttingsisaffectedbycavinganddrillingmudcontamination,ourresultsclearlyindicatethatcuttingsanalysisincombinationwithseismicandloggingdatatocoringindeepoceandrillingisaviableanaloguetocoreforgenerallithostratigraphicalinterpretationswhennoscientificrequirementsforprecisesedimen-tologicalanalysisarerequired.Tomakepreciselithostratigraphicaldescriptionandinterpretationincriticalintervals,thestudyofcoreisneeded.

7.3

Lithospheric heterogeneities, hydrothermal activity and serpentinization at slow spreading ridges: Insights through ocean drilling

Früh-GreenGretchen1,DelacourAdéilie1,2&BoschiChiara1,3

1ETH Zurich, Institute for Mineralogy & Petrology, Clausiusstr. 25, CH-8092 Zurich (frueh-green@erdw.ethz.ch)2IPGP, Equipe de Géoschiences Marines, F-75252 Paris Cedex 053 Istituto di Geoscienze e Georisorse-CNR, Via Moruzzi 1, I-56124 Pisa

The formation and alteration of the oceanic lithosphere are fundamental processes that determine the chemical andphysicalevolutionofourplanet.Inthenearly40-yearhistoryofthescientificoceandrillingprograms,alimitednumberofsiteshavebeendrilledintooceanicbasement;however,onlytwoholes,ODPHole735BandIODPHole1309D,havebeendrilledtodepths>1000minlowercrustalsequences.Thesehaveledtoabetterunderstandingofmid-oceanridgeprocessesand,inturn,haveledtotherecognitionoffundamentaldifferencesincrustalaccretionandalterationprocessesrelatedtospreadingrates.Incontrasttotheapparentlymorelayeredandspatiallyhomogeneousoceaniclithosphereatfast-spreadingridges(e.g.,ODPHole504BandHole1256D),slow-andultra-slowspreadingcentresaremarkedlyheterogeneouswithre-spect to lithology,deformationanddegreeofalteration.Theseheterogeneitiesreflectprofoundvariations inmagmatic,tectonicandhydrothermalactivityalong-andacross-isochrons.

AtmanysitesontheMid-AtlanticRidge(MAR),themagmaticlayerisdiscontinuousandmantlelithologiesareexposedatorneartheseafloorwithinoceaniccorecomplexes(OCCs):thefootwallsoflong-livedlow-angledetachmentfaults.IODPExpeditions304and305targetedthe1.5to2Myrolddome-likeAtlantisMassif,locatedjustwestoftheMARat30°N.TheAtlantisMassifformstheinsidecorneroftheintersectionbetweentheMARandtheAtlantisTransformFaultandisnowoneofthebeststudiedOCCcomprisedoflowercrustalanduppermantlerocks.Threedomainsaredistinguishedonthebasisoflithologyandmorphology:acentraldome,aperidotite-dominatedsouthernwallandabasalticeasternbloc,inter-pretedasahangingwallseparatedfromtheOCCbyadetachmentfault.HerewereviewrecentresultsofdrillingatSite1309onthecentraldomeoftheAtlantisMassif,andcomparethesewithresultsfromdetailedsubmersiblestudiesofthesouthernwall,5kmtothesouth.

Themainhole1309Dwasdrilledonthecrestofthecentraldomeofthemassiveatawaterdepthof1656mbsfandpene-trated1415.5mbsfwithanaveragecorerecovery75%.Quiteunexpectedly,thepredominantlithologyrecoveredwasgabb-roicrocks(91.4%)withminorintercalatedultramaficrocks(5.7%)anddiabase(~3%).Thegabbroicrocksarecompositionallydiverseandarethemostprimitiveevercoredinslow-spreadingoceanlithosphere(withhighMg#(74–90),lowTiO

2(<0.49

wt%)andNa2O(0.1–3.7wt%).Mantleperidotitesareveryrare(<0.3%)andareconcentratedintheupperpartofthehole.The

gabbroicrocksarerelativelyundeformedandshowlimitedseawater-rockinteractiondownhole,asindicatedbyrelativelyhomogeneousandmantle-likeSr-,Nd-,andS-isotopecompositions.

Thedominanceofprimitivegabbroicrocks,theabsenceofsignificantamountsofserpentinizedmantleperidotites,andthelowdegreeoffluid-rockinteractionatSite1309contrastsgreatlywithresultsofsubmersiblestudiesofthesouthernwallofthemassif.ThesouthernwalloftheAMisdominatedbyserpentinizedharzburgites,intrudedbyminorgabbroicbodies,andhoststherecentlydiscoveredLostCityHydrothermalField(LCHF),aperidotite-hostedhydrothermalsystemcomposed

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g ofspectacular,upto60mhigh,carbonateandbrucitechimneysthatventlow-temperatureandhigh-pHfluidsresultingfromserpentinizationreactionsatdepth.TheLostCityfluidsareenrichedinhydrogen,methaneandotherhydrocarbons,producedabioticallythroughFischer-Tropschtypereactions.Productionofreducedvolatilesandvariablemixingwithsea-waterinthesubsurfaceandinnear-ventenvironmentsareimportantprocessesincreatingstrongchemicalgradientsthatprovidemicro-niches fordistinct communitiesofhydrogen-, sulphur- andmethane-utilizingarchaea, bacteria aswell aseubacteria.GeochemicalinvestigationsoftheserpentiniteshostingLostCityindicatelong-livedseawater-peridotiteinterac-tionat150-250°Candhighfluid-rockratios(>100andupto106),whichproducedenrichmentsinB,UandlightREE,andsystematicchangesinSr-andNd-isotoperatiostowardsseawatervalues.OurmultidisciplinaryinvestigationsofLostCityhighlightthecomplexinterplaybetweendeformation,fluidflow,masstransferandmicrobialactivitywithinthislong-livedsystemandarechangingourviewsnotonlyabouttheconditionsunderwhichlifecanthriveonourplanetbut,perhaps,onothersaswell.

ThefactthatIODPHoleU1309DontheAtlantisMassif(AM)ontheMARunexpectedlyyielded1400mofgabbroadjacenttowhereperidotitehadpreviouslybeenrecovered,andclosetotheperidotite-hostedLostCityventfield,istestamenttohowlaterally variable magmatic accretion processes and hydrothermal activity are at slow spreading ridge environments.ThroughstudiesoftheAtlantisMassifanddrillingatODPSite209(alongtheMARfrom14°to16°NonbothsidesoftheFifteen-TwentyFractureZone),anewmodelforthestructureandformationofslow-spreadridgeshasemerged.Slowspread-ingridgesareprobablylessmagmastarvedthanpreviouslybelieved,butmeltisretainedintheupwellingmantleasitas-cends,andbecomesincorporatedintoarelativethicklithosphere.Thelatterdeformsandextendsalonglocalizedzonesofdeformation,someofwhichbecomemajordetachmentfaultsoperatingviaarollinghingemodel.Suchdetachmentfaultsmaythereforeatleastlocallyconstitutethedefactoplateboundary.Drillinghasalsocontributedtomodifyingournotionsofophiolitesasanaloguesforoceancrustformationandhasshownthatslow-spreadcrustcannotbeconsideredcomparabletodismemberedophioliticcrust.

7.4

Scientific drilling in the ocean lithosphere : what's next?

BenoîtIldefonse

Géosciences Montpellier, CNRS-Université Montpellier 2, CC60, 34095 Montpellier cedex 05, France (benoit.ildefonse@um2.fr)

Themid-oceanridgesandthenewoceaniclithospherethattheycreatearetheprincipalpathwayforthermalexchangeandphysical/chemical interactionsbetween theearth’s interior, thehydrosphere,and thebiosphere.Hence theocean lithos-phererecordstheinventoryofglobalthermal,chemicalandassociatedbiologicalfluxes.

AkeyoutcomeoftheInterRidge-IODP"Melting,Magma,FluidsandLife"workshop(Southampton,27-29July,2009;www.interridge.org/WG/DeepEarthSampling/workshop2009)was the formulation of integrative scientific questions and imple-mentationapproachesthatwillelucidatetheroleofoceanlithosphereprocesseswithinthebroaderEarthSystem.Therearethree,equallyimportantmainthemes,eachcomprisinggeological,hydrological,chemical,andbiologicalprocessesthatarecloselyinterdependent.

• Understandingtheaccretionofoceancrust.Thisgoalrequiresfullsectioncharacterizationofminimally-disruptedoceancrustandasufficientportionofunderlyinguppermostmantle,anddetailedunderstandingofactiveprocesseswithintheaxialzone;

• Understandinglithosphericheterogeneityinslow-andultraslowspreadcrust,inparticulartheimpactofserpentiniza-tiononglobalbiogeochemicalcyclesandplaterheology.

• Followingthematurationprocessof lithospherefromtheaxistotheridgeflanksandinvestigatingthehydrological-geochemical-microbiologicalfeedbacksduringtheagingoftheoceanicbasement.

Focussinginonthefirst theme,samplingacompletesectionoftheoceancrust, fromtheoceanfloortotheuppermostmantlethroughtheseismicMohorovičičdiscontinuity(the'Moho'),wastheoriginalinspirationforscientificoceandrilling,andremainsthemaingoalofthe21stCenturyMoholeInitiativeintheIODPSciencePlan.Fundamentalquestionsaboutthecomposition,structure,andgeophysicalcharacteristicsoftheoceanlithosphere,andaboutthemagnitudeofchemicalex-changesbetweenthemantle,crustandoceansremainunansweredduetotheabsenceofin-situsamplesandmeasurements.ThegeologicalnatureoftheMohoitselfremainspoorlyconstrained.The“MissionMoho”proposalsubmittedtoIODPinApril2007,setstheambitiousgoaltodrillcompletelythroughintactoceaniccrust,acrosstheMohoandintotheuppermostmantle,inlithosphereformedatafastspreadingrate.Although,no

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inglong-termmissionhasbeenadoptedbyIODP,thescientificobjectivesrelatedtodeepdrillingintheoceancrustremaines-

sential to our understanding of the Earth.Our current knowledge if in-situ ocean crust remains limited;muchwill belearnedonthewaytothemantle.Thejourneyandthedestinationareequallyimportant.

Fundamentalscientificgoalsinclude:• Determinethebulkcompositionoftheoceaniccrusttoestablishthechemicallinksbetweeneruptedlavasandprimary

mantlemelts,understandtheextentandintensityofseawaterhydrothermalexchangewiththelithosphere,andesti-matethechemicalfluxesreturnedtothemantlebysubduction,

• Testcompetinghypothesesoftheoceancrustaccretionatfastspreadingmid-oceanridges,andquantifythelinkagesandfeedbacksbetweenmagmaintrusion,hydrothermalcirculationandtectonicactivity,

• DeterminethegeologicalmeaningoftheMohoindifferentoceanicsettings,

• Determinetheinsitucomposition,structureandphysicalpropertiesoftheuppermostmantle(anditsvariability),andunderstandmantlemeltmigration,

• Calibrateregionalseismicmeasurementsagainstrecoveredcoresandboreholemeasurements,andunderstandtheori-ginofmarinemagneticanomalies,

• Establishthedepthlimitofdeepbiosphereandhydrological/geobiologicalprocessesinthelithosphere.

The“MoHole”wasplannedasthefinalstageofMissionMoho.AttherecentInterRIDGE-IODPWorkshop"Melting,Magma,Fluids,Life",scientistsre-iteratedtheirenthusiasmandsupportforanultra-deepholeinintactoceaniccrustandintotheuppermostmantle.Thisprojectwouldprovidemajorinspirationforthenextgenerationofscientistsandengineers.Thechallengeisformidable,andrequiresassoonasfeasiblecarefulsiteselection,geophysicalsitesurvey,andthedevelopmentofcuttingedgetechnologyincludingdrillingcapabilitytoachieve+6000mofpenetrationin+4000mwaterdepth.Thenextdrillingprogramneedsamechanismtoenablethecommunitytomoveforwardwithplanning,designandimplementationinordertocompleteoneofthemajorgoalsofscientificoceandrilling.

7.5

The age of sedimentary fillings of overdeepend valleys in the Alps

FrankPreusser

Institut für Geologie, Universität Bern, Baltzerstrasse 1+3, 3012 Bern, Switzerland (preusser@geo.unibe.ch)

OverdeepenedbasinsandvalleysareknownfromseveralareaswithintheAlps,inparticularfromSwitzerlandandnorthernItaly(e.g.Schlüchter,1979).Itisfurthermoreremarkablethatglacialerosionpartlyleftremainsofolderdepositsinlateralvalley positions such as Gnadenwaldterrasse of the Inn Valley (Fliri et al., 1973), Austria, or Thalgut in the Aare Valley(Schlüchter,1989),Switzerland,thatrepresentformervalleybottoms.SeveralofthedeepbasinsandrelicscontaincomplexsedimentarysequencesthatindicatedepositionbeforethelastglaciationoftheAlps(Würmian).Recentresultsfrompaly-nologyandluminescencedatingindicateacomplexdepositionhistoryforsuchsediments,forexampleforthecomplexse-quenceofMeikirch,AareValley(Preusseretal.,2005).Theavailabledataimpliesthatdeeperosionandshapingofthepre-sentsubsurfaceoccurredthroughoutseveralphasesduringtheQuaternary.However,theexacttimingoftheseprocessesisstillpoorlyconstrainedasthenumberofsitesavailableisratherlimited.Sincemostofthevalleyfillingsaredeeplycoveredbysedimentsoflaterglaciations,furtherdetailedinformationaboutthisissuecanonlybeachievedbyrecoveringcoresfromsuchstructuresbydeepdrillings(downtosomehundredmetres).FirstresultsfromacasestudyintheWehntal(ZüricherUnterland)willbepresented.

REFERENCESFliri,F.,1973.BeiträgezurGeschichtederalpinenWürmvereisungen:ForschungenamBändertonvonBaumkirchen(Inntal,

Nordtirol).ZeitschriftfürGeomorphologieSupplement16,1-14.Preusser,F.,Drescher-Schneider,R.,Fiebig,M.,Schlüchter,Ch.,2005.Re-interpretationoftheMeikirchpollenrecord,Swiss

AlpineForeland,andimplicationsforMiddlePleistocenechronostratigraphy.JournalofQuaternaryScience20,607-620.Schlüchter,Ch.,1979.ÜbertiefteTalabschnitte imBernerMittellandzwischenAlpenund Jura (Schweiz).Eiszeitalterund

Gegenwart29,101-113.Schlüchter, Ch., 1989. The most complete Quaternary record of the Swiss Alpine Foreland. Palaeogeography,

Palaeoclimatology,Palaeoecology72,141-146.

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New sights on Late Pleistocene climate variability in Southernmost Patagonia: An ICDP approach

C.Recasens1,D.Ariztegui1,N.I.Maidana2,F.S.Anselmetti3,A.Vuillemin1,R.Farah1andthePasadoScientificTeam

1Section of Earth and Environmental Science, Rue des Maraîchers 13, 1205 Geneva (cristina.recasens@unige.ch)2 Dpto de Biodiversidad y Biología Experimental, FCEyN-UBA, Buenos Aires, Argentina3 EAWAG, Überlandstrasse 133, 8600 Dübendorf

Laguna Potrok Aike, at 52°S, 70°W in Southern Patagonia, contains a unique paleoclimatic record of southern SouthAmerica.This~770kaoldmaarlocatedintheprovinceofSantaCruz,Argentina,isoneofthefewpermanentlakesinthisstepperegion,providingacontinuoussedimentaryrecordoveranextendedtimespaninthisareaoftheworld.WithintheframeworkoftheICDP-sponsoredPotrokAikeMaarLakeSedimentArchiveDrillingProject(PASADO),threesiteswerecoredduringOctober andNovember 2008 by an international group of scientists using theGLAD800 drilling rig operated byDOSSEC(Figure1).

Figure1.BathymetricmapofLagunaPotrokAikewithdrillsitesPTA1andPTA2andholeslabeledalphabetically.PTA-1Eto-1HandPTA-

2Dto-2Faregravitycorescoveringthesedimentwaterinterface.InsertsshowlocationofthelakeinsouthernSouthAmerica.Thevolca-

noesReclús(R),Hudson(H)andMt.Burney(B)aremarkedwithcapitalletters.

ThelakeislocatedinthePliocenetolateQuaternaryPaliAikeVolcanicField,anorthwest-southeastorientedtectono-volca-nicbeltthatis~50kmwideandmorethan150kmlong.TheavailablegeomorphologicaldataindicatethatLagunaPotrokAikehasneitherbeenreachedbythelastglaciationnorbyanyotherPleistoceneiceadvanceduringthelast1Ma.Thus,itispotentiallytheonlysitethathasarchivedacontinuousandhigh-resolutionsedimentrecordcoveringseveralglacial/in-terglacialcyclesforthesouthernhemisphericmid-latitudes.Severaldrillingsiteswerechosenaftertheinterpretationoftheseismicprofilesobtainedinpriorfieldcampaigns,withintheframeworkoftheproject“SALSA”,SouthArgentineanLakeSedimentArchivesandModeling(Anselmettietal.2008,Willeetal.,2007).Morethan500mofsedimentarycoreswerere-coveredandthelongestcorereachedover100m.

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On-sitelaboratoryanalyseswerecarriedoutsimultaneouslytothedrillingoperations.AllcoresectionswerescannedforpetrophysicalpropertiespriortoopeningwithaGeoTek®MultisensorTrackCoreLogger(MSCL).Aninsitugeochemicalla-boratorywasalsohabilitatedinordertoachievethefirstanalysisontherecoveredmaterial.Corecatchers(approximatelyoneeverythreemeters)werephotographedanddescribed,andthensubsampledforwatercontent,CaandClcontentsaswellaspHwhichweremeasuredimmediatelyinthecamp.Sampleswerefurthermoretakenforstableisotopes,pollenanddiatomsforsubsequentanalysisinthehomebasedlaboratories.Smearslidesweremountedforpetrographicmicroscopicexamination.

Aninternationalscientificteamwillworkonthedifferentsedimentarycoresrecoveredatthethreesitesusingamultidisci-plinaryapproach.SeveralanalysesarecurrentlyunderwayincludingmoreaccurateMSCLscansofthecoresandcorecatcheranalysisfordiatoms,pollenandstableisotopes.AsamplingpartyatthecorerepositoryinBremen,Germany,isactuallyonthego.Coreshavebeensplitandarebeingsampledathighresolutionforalltheplannedanalyses.TheSwissscientificcontributiontotheprojectinvolvestwomainaspects:1.thediatomrecordoftheretrievedcoresforpaleoenvironmental reconstructions and collaboration in the development of a modern training set for diatoms inPatagonia;2.thecharacterizationofthedeepbiosphereinvestigatinglivingmicrobialcommunitieswithinthesediments,whichisembeddedinanintegratedstudyincludingmicrobiology,geochemistry(interstitialwaters),andmineralauthige-nesis/diagenesis.

REFERENCESAnselmetti,F.S.etal.,2008:EnvironmentalhistoryofsouthernPatagoniaunravelledbytheseismicstratigraphyofLaguna

PotrokAike.Sedimentology,53,873-892.Wille,M.,etal.,2007:VegetationandclimatedynamicsinsouthernSouthAmerica:ThemicrofossilrecordofLagunaPotrok

Aike,SantaCruz,Argentina.ReviewofPalaeobotanyandPalynology,146,234–246.

7.7

PALEOVAN - The International Continental Scientific Drilling Program (ICDP) in Lake Van, Eastern Anatolia (Turkey)

MonaStockhecke1,FlavioS.Anselmetti1,AysegülF.Meydan2,PaulHammer3,RolfKipfer1,DanielOdermatt4,MikeSturm1,YamaTomonaga1andPALEOVANscientificteam

1Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland (mona.stockhecke@eawag.ch)2 Yuzuncu Yil Universitesi, Muhendislik-Mimarlik Fakultesi, Jeoloji Muhendisligi Bolumu 65080, Van, Turkey3 Dept. of Earth Science, Haldenbachstrasse 44, 8092 Zurich, Switzerland4 Remote Sensing Laboratories, Dept. of Geography, University Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland

LakeVanisthefourthlargestterminallakeintheworld(volume607km3,area3,570km2,maximumdepth460m),extend-ingover130kmWSW-ENEontheEasternAnatolianhigh-plateau,Turkey.Theannually-laminatedsedimentaryrecordofLakeVanpromisestobeanexcellentpalaeoclimatearchivebecauseitpotentiallyyieldsalongandcontinuouscontinentalsequencethatcoversseveralglacial-interglacialcycles(~500kyr).Therefore,LakeVanisakeysitewithintheInternationalContinentalScientificDrillingProgram(ICDP)fortheinvestigationoftheQuaternaryclimateandpaleoenvironmentalevo-lutionintheNearEast.TheICDPdrillingoperations'Paleovan'willbeperformedwithactiveinvolvementofvariousSwissresearchgroups.Drillingisplannedfor2010andthetechnicalpreparationsarecurrentlyunderway.

Aspreparationforthedrillingcampaign,severalsitesurveyswerecarriedoutduringthepastyearsconsistingof~850kmseismicprofiles,multidisciplinaryanalysisofupto9mlongcoresextendingbacktotheLastGlacialMaximumandwatercolumnanalysis.Furthermore,recentinvestigationsfocusedonmodernparticledynamicsandvarveformationusingse-quentialsedimenttraps,multispectralsatelliteimagesandshortsedimentcores(Stockhecke,2008).

Thesedimenttrapsamplesandsatelliteimagesof2006revealedthatthreeannualphasesofauthigenicparticleproductionoccur,oneinspringcharacterizedbynon-skeletalalgae,oneinsummerwithdominanceofauthigeniccarbonateproduc-tion,andoneinautumn,whichischaracterizedbydiatomsandthusbiogenicsilicaproduction.Thesedimenttrapsamplesfrom2007to2008showthesameorganicspring-peakastheyearbefore,butthebiogenicsilicaconcentrationincreasedsi-

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g gnificantly. Themaxima of authigenic carbonate production in late autumnof 2008 is related to significant higher airtemperaturesand increasedwatermixingprocessesat thecorrespondingdepth.Further investigationsareplannedthatdocumenttheannualcycleswithseasonalresolutionandtheirpreservationpotentialinthelakesediments,calibratingthesensitiveclimate-lake-sedimentsystem.

AlltheseinvestigationsshowthelargepotentialofPALEOVANforobtainingacontinuousundisturbedandlongcontinentalpalaeoclimaterecord.Thiswillshednewlightsonpaleoenvironmentalconditions,thedynamicsoflakelevelfluctuations,noblegasconcentrationinporewaters,historyofvolcanismandandearthquakeactivities(Litt,2008).

Figure1.PartofseismicprofileGEO04-007crossingtheTatvanBasinandAhlatRidgeinaS-NdirectionwiththeproposedICDPdrillsite.

REFERENCESLitt,T.,Krastel,S.,Sturm,M.,Kipfer,R.,Örcen,S.,Heumann,G.,Franz,S.O.,Ülgen,U.B.,Niessen,F.,2008,submitted:Lake

VanDrillingProject“PALEOVAN”,InternationalContinentalScientificDrillingProgram(ICDP):Resultsofarecentpre-sitesurveyandperspectives.QuaternaryScienceRewies.

Stockhecke,M. (2008). TheAnnual ParticleCycle of LakeVan: Insights fromSpace, Sediments and theWaterColumn.UniversityofZurich.

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Addressing Geohazards from Submarine Slides through Ocean Drilling: The “Nankai Trough Submarine Landslide History” drilling Proposal

StrasserMichael1,MooreGregoryF.2,AshiJuichiro3,CamerlenghiAngelo4,DuganBrandon5,HuhnKatrin1,KanamatsuToshiya6,KawamuraKiichiro7,McAdooBrianG.8,PanieriGiuliana9,PiniGian-Andrea9,UrgelesRoger4

1 MARUM, Centre for Marine and Environmental Sciences, Univ. Bremen, Leobener Strasse, D-28359 Bremen (mstrasser@marum.de)2 Dept. of Geology and Geophysics, Univ. Hawaii, USA3 Ocean Research Institute, Univ.Tokyo, JPN4 ICREA – Univ. Barcelona, ESP5 Dept. of Earth Science, Rice Univ. USA6 Japan Agency for marine-earth science and technology JAMSTEC, JPN7 Fukada Geol. Inst. Tokyo, JPN8 Dept. of Earth Sciences & Geography Vassar College, NY, USA9 Dept. of Eartn and Geo-Environmental Sciences, Unv. Bologna, ITA

Withincreasingawarenessofoceanicgeohazards(e.g.Morganetal.,2009),alsosubmarinelandslidesarewidegainingat-tentionnotonlybecauseoftheircatastrophicimpacts(e.g.landslide-inducedtsunamis,submarineinfrastructure),butalsobecausetheycanbedirectlyrelatedtoprimarytriggermechanismsincludingearthquakes,rapidsedimentation,gasrelease,orclathratedissociation,manyofwhichrepresentgeohazardsthemselves(e.g.Camerlenghietal.,2007).Scientificoceandrillingcanbeakeyelementinunderstandingsuchgeohazards,giventhatthesubmarinegeologicalrecordpreservesstruc-turesandpastoccurrences.Toimproveourknowledge,quantitativeconstraintsonfrequencyandmagnitudeonrelevanttimescalesneedtoberelatedtotriggerandfailuremechanisms.

Towardsthisgoal,theIODP-AncillaryProjectLetter-Proposal“NankaiTroughSubmarineLandSLIDEHistory–NanTroSLIDE”aimstoaddonesitetotheNanTroSEIZE(NankaiTroughSeismogenicZoneExperiment;TobinandKinoshita,2007)studyareatoconstraintiming,causesandconsequencesofsubmarinelandslidesinthiswell-studiedaccretionarycomplex.Onthebasisofnew3DseismicdatainterpretationintheNanTroSEIZEstudyarea,wehaveidentifiedanideallysuitedslopebasinsedimentarysuccessionthatiscomposedofstackedPleistocene-to-recentmasstransportdeposits(MTDs)thatincludesoneexceptionallylargeMTDupto150minthickness.A350mthicksuccession,comprisingthedistalpartofthemegadeposit,isproposed tobecompletelydrilledand loggedwithin3daysbefore,duringorafteranyof theupcomingNanTroSEIZEoperationsontheJapanesedrillingvesselChickyu.

WeexpecttocatalogadetailedsubmarinelandslideeventhistoryalongwithcluesonthedepositionaldynamicsofeachMTDastheyrelatetotsunamigenicpotential.Inconjunctionwith3Dseismicinterpretationwewillbeabletoconstrainscalesand landslidemagnitude.Theresultsobtainedwillbe interpreted intermsof short-termtriggermechanismsandlong-termpre-conditioningfactorsbycorrelatingthemagnitudesandfrequenciesofMTDstotheseismicityandtectonicevolutionof themargin.Additionally,data fromnearbyNanTroSEIZEdrill sitesareexpectedtorevealquantitativecons-traintsonslopestabilityconditionsandsubmarinelandslidesinitiation.Incombination,theavailabledatasetwillallowustoestablishabetterphysicalunderstandingoftectonicprocessesandslopefailures,togainageneralunderstandingoffai-lure-relatedsedimentationpatternsandthesignificanceoflargeepisodicmass-transportevents.Ultimately,thiscouldhelpustoassesthetsunamigenicpotentialofsubmarinelandslides.Wethusexpectthisproposedprojecttobecomeanimpor-tant case study providing the base to improve our conceptual understanding of causes and consequences of submarinelandslides.

Theprimarygoalsofdrillingtheproposedsite(NTS-1A)are:(i) Toestablishawell-datedPleistocene-to-recentmass-movementeventstratigraphy(ii) TosamplethedistalpartofanexceptionallythickMTDforanalyzingitsrheologicalbehaviortoconstrainsliding

dynamicsandtsunamigenicpotential

Thisaimsatprovidinganswerstofollowingquestions:1) Whatisthefrequencyofsubmarinelandslides2) HowareMTDsandearthquakesrelatedandcanweusetheMTD-inventorytointerpretpaleoseismology3) Whatcontrolstype,sizeandmagnitudeofturbitidesandMTDsandhowdotheychangethroughtime?4) Whatarethedynamicsoflargesubmarinelandslidesandcanweinferthertsunamigenicpotential?

Byaddressingthesefocusedkeyquestions,weaimtoisolatetectonicprocessesinfluencingmagnitudeandoccurrenceofsubmarinelandslidesalongactivesubductionzonemarginsandtounderstandtheirpotentialfortriggeringcatastrophicconsequencesbothintermsofhazard(tsunamigeniclandslides)andofsedimentmass-transferandmarginevolution.

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REFERENCESCamerlenghi,A.,Urgeles,R.,Ercilla,G.,andBruckmann,W.,2007.Scientificoceandrillingbehindtheassessmentofgeo-

hazardsfromsubmarineslides,ScientificDrilling,4,45-47Morgan,J.K.,Silver,E.,Camerlenghi,A.,DuganB.,Kirby,S.,Shipp,C.,Suyehiro,K.,2009.AddressingGeohazardsThrough

OceanDrilling.ScientificDrilling,7,15-30Tobin,H.,andKinoshita,M.,2007.TheIODPNankaiTroughSeismogenicZoneExperiment.ScientificDrilling,1,39-41

7.9

Evidence for a middle Pliocene change in the ocean nitrate inventory based on foraminifera-bound δ15N in the Caribbean Sea

StraubMarietta1,HaugGerald1,DanielSigman2,HaojiaRen2

1 Geological Institute, Department of Earth Sciences, ETH Zurich, 8092 Zurich, Switzerland2 Department of Geosciences, Guyot Hall, Princeton University, Princeton, NJ 08544, USA

Thenitratebudgetinthelow-latitudesurfaceoceanismainlycontrolledbythetypicallyopposingeffectsofdenitrificationandnitratefixation.Thestateoftheglobaloceannitrateinventoryaffectsprimaryproduction,whichallowssequesteringCO2intothedeepocean.ThismayinfluenceclimatevariabilityandcontrolwarmandcoldperiodsinEarthhistory.Studieshaveshownthatnitrogenisotopesreflectthenutrientstatusoftheupperwatercolumnandthereforeareaproxyforthestateoftheocean’s‘biologicalpump’.

Sofar,theNinventoryhasmostlybeenreconstructedbasedonbulksedimentaryN-isotopemeasurements,whichcanbeaffectedbysyn-andpost-sedimentaryprocesses.Promisingapproachestocircumventthesepotentialbiasesarebasedonmeasurementsofforaminifera-boundδ15N.Inthesubtropicalandtropicalocean,planktonicforaminiferaareamaincom-ponentofthesinkingparticleflux.Theorganiccompoundsencapsulatedwithintheforaminiferaltestsareprotectedfromsedimentarydiageneticprocesses.Asaresulttheyrecordapristinesignalofthenitratecompositioninthewatercolumn.ThenovelmethodusedhereemploysdenitrifyingbacteriaPseudomonaschlororaphisandPseudomonasaureofaciens toproducenitrousoxide(N

2O),recoveredfromthenitrateextractedfromtheorganicmattershelteredwithintheforaminifera

shell,whichisanalyzedforδ15NwithaGasbenchII–IRMSandproducesresultswithreproducibleisotopicmeasurementsofsamplesdownto1μMnitrate.

Previousdatafromtheinvestigatedsite(ODPLeg165,site999A,CaribbeanSea),studyingthelast30’000yrsusingthesamemethod,indicateasystematicdifferencebetweenglacialandinterglacialvalues.Theglacialstateischaracterizedbyhighδ15Nvaluesaround~5‰(suggestinglessN-fixation)andtheinterglacialstatebylowδ15Nvaluesaround~3‰(N-fixationincrease).Oncontrary,ourdatafromforaminifera-boundδ15NofG.ruberandG.sacculiferrevealsevidenceforachangeinthemeanoceannitratecomparedtothelast30’000yrs.Thebasicfindingsfromthemeasuredintervalbetween3.2Mato2.4Mashowglacialδ15Nvaluesof~4.5-7‰forG.sacculiferand~3-5.5‰forG.ruber,interglacialvaluesrangebetween~4-6‰forG.sacculiferandbetween~3-5.5‰forG.ruber.Basedontheobtainedδ15Nvalueswecouldnotdifferentiatebetweenglacialandinterglacialperiods.Thisleadustotheconclusionthatthereprobablywasageneralchangeoftheoceannitrateinven-tory and the dominating processes of N-fixation and denitrification performed in a different way than today. Furthermeasurementswillbenecessarytounderstandthepreliminarydataandtointerpretthepossiblechangesintheoceandu-ringlatePliocene.

REFERENCESM.A.Altabet,R. Francois (1994): Sedimentarynitrogen isotopic ratio as a recorder for surfaceoceannitrateutilization.

Globalbiochemicalcycles,Vol.8,No.1,Pages103-116.G.H.Haug,R.Tiedemann,R.Zahn,A.C.Ravelo(2001):RoleofPanamaupliftonoceanicfreshwaterbalance.Geology,Vol.29,

Pages207-210.H.Ren,D.M.Sigman,A.N.Meckler,B.Plessen,R.S.Robinson,Y.Rosenthal,G.H.Haug(2009):ForaminiferalIsotopeEvidence

ofReducedNitrogenFixationintheIceAgeAtlanticOcean.Science,Vol.323,Pages244-248.D.M. Sigman,K.L.Casciotti,M.Andreani,C.Barford,M.Galanter, J.K.Bhlke (2009):ABacterialMethod for theNitrogen

IsotopicAnalysisofNitrateinSeawaterandFreshwater.Analyticalchemistry,Vol.73,No.17.Pages4145-4153.D.M.Sigman,S.L.Jaccard,G.H.Haug(2004):Polaroceanstratificationinacoldclimate.Nature,Vol.428.Pages59-63.

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New prospects in ICDP research: investigating the subsurface biosphere in Lake Potrok-Aike sediments

A.Vuillemin1,D.Ariztegui1,J.Pawlowski2,S.Templer3andthePASADOScientificTeam

1 Section of Earth & Environmental Sciences, University of Geneva, 13 rue des Maraîchers, 1205 Geneva, Switzerland (aurele.vuillemin@unige.ch)

2Section of Biology, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva, Switzerland3Massachusetts Institute of Technology, Massachusetts Institute of Technology, 77 Massachusetts avenue, 02139 Cambridge, USA

Microbialactivityonrecentsediments is fullyrecognizedasamajorplayerinlithificationprocesses.Theseomnipresentorganismshavethecapacityofcatalyzingandenhancingdiageneticreactionseveninextremeenvironmentsfromtheverysurfaceofthesedimentstoasdeepas4.5kmbelowthewatercolumn.Livingbacterialcommunitieshavebeentrackeddownintodeepsedimentsandevenintothedeeperbasalticsub-seafloors.Althoughthedistributionanddiversityofmicrobesinmarinesedimentsthroughdepthhavebeenstudiedforsomeyearsalready,thereisalackoftheseinvestigationsinthela-custrinerealm.

Furthermore,geomicrobiologystudiesinmodernlakesallowtakingacloserlookintoearlydiageneticprocesseslinkedtomicrobialactivity insubrecentsediments.Thefociofmostofthesestudies,however,havebeeneitherveryshallowsedi-mentsand/orthewatercolumn.

Morethan500metersofsedimentarycoreswereretrievedfromLakePortokAike,acraterlakelocatedinSouthernPatagoniawithintheframeworkoftheICDP-sponsoredPASADOproject(PotrokAikeMaarLakeSedimentArchiveDrillingProject).A100meterslongcorewasdedicatedtogeomicrobiologysampling,allowingtheinspectionofundisturbeddeeplacustrinesediments.Specialwindowswerecutinthelinersfordirectsamplingunderthemoststerileconditionspossibleimmedia-telyaftercorerecovery.InsituATPmeasurementsareusedasindicationoflivingorganismswithinthesediments.Varioussampleswerechemicallyfixedand/orfrozenformethanedetermination,bacterialcellcounting,DGGE(molecularfinger-printingtechnique)andcellcultivation.

InsituATPdatarevealaconstantlowmicrobialactivitybelow40msedimentdepthwhereasthreemainpeaksappearat34,10and5metersrespectively.Studyingthemicrobialcommunitybasedon16SrDNA,weidentifiedabroad,butconserveddiversitypatternintheoldersediments.Incontrast,thediversityseemstodecreaseandchangedramaticallyintheuppersection.ApreliminaryinterpretationoftheseresultssuggeststhateachATPpeakcorrelateswithmicrobialcommunityin-terphases.Thelattertogetherwiththenegativecorrelationbetweenactivityanddiversitymayindicatethatnutrientsaresystematicallydepletedthroughbacterialactivitycyclessinceeachindividualcommunitymaybeatleastpartiallyfedbythemetabolicproductsoftheoverlyingcommunity.Adaptionbecomesnecessaryforcommunitiesevolvinginenvironmentswithdecreasingtrophicstate.

Theintegrationofthesedatasetwithongoingmultiproxystudiesinthesamerecordwillbringnewlightintomicrobialactivityinlacustrinesystemsandtheirroleonvariousdiageneticprocesses.

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acquisition to modelling and visualisationNils Oesterling, Adrian Wiget, Massimiliano Cannata, Erich Zechner

Swiss Geological Survey; Swiss Geodetic Commission; Swiss Geotechnical Commission; Swiss Geophysical Commission; Swiss Hydrogeological Society

8.1 AntonovicM.:GeoShield:aserversideuserpermissionsmanagementtoOGCservices

8.2 BaillieuxP.,SchillE.:Preliminary3DfaultmodeloftheEuropeangeothermalsite(Soultz-sous-Forêts,France)

8.3 Baland P. & Möri A. : Converting geological maps to vector datasets – Completing the National GeologicalInformation

8.4 BaruffiniM.:Risk,measuredriskaversionandindividualcharacteristics

8.5 BaruffiniM.,ThüringM.:SystematicanalysisofnaturalhazardsalonginfrastructurenetworksusingaGIS-toolforriskassessment

8.6 BaumbergerR.,OesterlingN.:Challengesforgeologicalsurveysingeological3Dmodelbuildingandvalidation

8.7 BeresM.,KühniA.:OverviewofavailablegeosciencedatainSwitzerland

8.8 BiassS.,ParmigianiA.,Dell’OroL.,SenegasO.&BonadonnaC.:Exposure-basedriskassessmentfortephraaccumula-tion:theexampleofCotopaxivolcano(Ecuador)

8.9 BilgotS.,ParriauxA.:GIS-basedmethodforgroundwatermanagementandprotection:geotypesserving3Dapplica-tions

8.10 BorghiA.,RenardP.&JenniS.:Apseudo-geneticapproachforthestochasticgenerationofkarsticnetworks

8.11 BruijnR.,ZapponeA.,BurliniL.,TripoliB.,HolligerK.,BurgJ-P.&KisslingE. :SAPHYR,theSwissatlasofphysicalpropertiesofrocks

8.12 CannataM.,AntonovicM.:IstSOS:SensorObservationServiceinPytho

8.13 ComunianA.,StraubhaarJ.,RenardP.,FroidevauxR.:Modelingheterogeneousgeologicalreservoirsusingmultiple-pointstatisticssimulations

8.14 DresmannH.,ZechnerE.,HuggenbergerP.&EptingJ.:Differentresolutionsfordifferenttopics-thegeological3D-modeloftheBaselregion

8.15 FraefelM.,KockS.:UseofdigitalterrainmodelsandGISforneotectonicstudies:AnalysingfluvialterracemorphologyinnorthernSwitzerland

8.16 HilbeM.,Anselmetti F.S.,EilertsenR.,HansenL. : Insights fromtwohigh-resolutionbathymetric surveys inSwisslakes

8.17 Kuchler F.,CherixaG., SauvainaR., Storelli S., LindemannD.,AndreyE. : SyGEMe, IntegratedMunicipal FacilitiesManagementofWaterRessources:Toolpresentation,choiceoftechnology,man-machineinterface,businessoppor-tunitiesandprospects

8.18 KühniA.,OesterlingN.:Key-Note:TowardsaSwissGeologicalInformationsystem

8.19 LimpachP.,GrimmD.:Rockglaciermonitoringwithlow-costGPSreceivers

8.20 MarzocchiR.,CannataM.:AGISembeddedmodelfordambreak

8.21 MarzocchiR.,FedericiB.,SguersoD. :AGIS tool tocreate fluvial floodingmaps. Interactionof1DhydrodynamicmodelandGIS

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8.22 MeierA.,WiliC.:NaturereignisseentlangderBahnlinien:einesystematischeAufnahme

8.23 MolinariM.,CannataM.,TroungXuanL.:ShallowLandslideVulnerabilityAssessment

8.24 RenardP.,MariethozG.&StraubhaarJ.:3Dmodelingofgeologicalheterogeneity:thedirectsamplingmultiple-pointssimulationmethod

8.25 SaraswatP.:ParticleSwarmandDifferentialEvolutionoptimization-GlobaloptimizationforGeophysicalInversion

8.26 SteblerY.,SchaerP.,SkaloudJ.:FastColorization,AnalysesandVisualizationofAirborneLaserData

8.27 StrählS.,KuhnN.J.:Topographyandsurfaceprocessesinborderlineecotones

8.28 StraskyS.,BalandP.,OesterlingN.andKühniA.:TowardsaSwissgeologicaldatamodel

8.29 TripoliB.,ZapponeA,BurliniL.,BurgJ-P.,Hollinger,K.&Kissling,E.:TheSwissAtlasofPhysicalPropertiesofRocks(SAPHYR)

8.30 VilligerA.,HellerO.,GeigerA.,KahleH-G&BrockmannE.:EstimationoflocaltectonicmovementsusingcontinuousGNSSnetwork

8.1

GeoShield: a server side user permissions management to OGC services

MilanAntonovic

Institute of Earth Sciences – SUPSI

GeoShieldisaprojectborntoofferacentralizedwaytodefinesecurityaccess-controltogeo-services.Itactslikeaproxy,interceptingallthecommunicationsbetweenclientsandOGCcompliantservices(WMS,WFS,WPS,SOS).

GeoShield isabletomanageusersandgroups, ithandlesauthenticationandprivilegessettingsamonggroupsandregi-steredservices.Itiscapabletoanalyserequestsapplyingthefilterssettedtotheuserandmanipulatingtheresponse.

ForexamplehandlingWMSsecurity,withGeoShieldwecan:• defineaccessprivilegeforeachlayerprovidedbytheservice,• specifyifalayercanbeviewedornot,• definegeometricalextentofviewpermission.

Allprivilegesonsingle layersarebasedonCommonQueryLanguage (CQL) filters, thatallowinterestingcombinationofpermissionsdefinitionthatoperateinahiddenwaytoend-user.

Technicalinfo• ThecoreofGeoShieldiswritteninJavaandrelyonGeoTools.• ThedatabaseusedforstoringdataisPostgreSQL.• Authenticationmethodisthe“HTTPAuthentication:BasicAccessAuthentication”,thatguaranteecompatibilitieswith

mostoftheclients(likeuDig,ArcGis,Google-Earth,etc.)•WebinterfacebuildwithExtJSandOpenLayers

REFERENCESGeoShield-http://istgeo.ist.supsi.ch/site/projects/geoshieldOGC(OpenGeospatialConsortium)-www.opengeospatial.orgGeotools-http://geotools.codehaus.org/ExtJs-extjs.comOpenLayers-openlayers.org

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Preliminary 3D fault model of the European geothermal site (Soultz-sous-Forêts, France)

BaillieuxPaul1,SchillEva1

1Laboratoire de Géothermie, Université de Neuchâte, Rue Emile Argand 11, CH-2009, Neuchâtel, Suisse (paul.baillieux@unine.ch)

ThegeothermalresourcesattheEuropeantestsiteatSoultz-sous-ForêtsarestronglyrelatedtoapproximatelyN-Sstrikingnormalfaultsystems(e.g.Bächler,2003).Fluidcirculationingeneralandinparticularalongfaultsystemsisaveryeffectiveheattransportmechanismcomparedtoconductiveheattransport.IntheareasofLandau(Germany)andSoultz(France),fluidconvectionhasbeenusedtoexplainthetemperaturedistributionatdepth.InthecaseofLandau,fluidconvectionhasbeensimulatedinaverticalfaultinordertoexplainthedistributionofrelativelywarmandcoldzonesalongtheOmega-fault(Bächleretal.2003).

Intheproject“GeothermalresourcesofRhineland-Palatine”(Schilletal.,2007,Schilletal.,2009),geological3DmodelswereperformedfortheareasBadBergzabern,Landau,andSpeyer.IthasbeenshownthatthemajorthermalanomaliesintheRhinevalleyarerelatedtohorststructures.TheinversionofthegravitydataintheSoultzarearevealsalowdensityanom-aly,whichcoincideswiththeSoultzhorststructure.Suchlowdensitycanberelatedtohighporosity.2DMagnetotelluricmeasurementsacrosstheSoultzhorstrevealahighelectricconductivityinthewesternpartofthehorstbetweentheSoultzandKutzenhausenfaultsatthetopgranite.Highelectricconductivitycanberelatedthegeothermalbrinewithmeanresis-tivityofabout0.1Ohmm.

Inordertoinvestigatetheformationofthesetypesofgeothermalreservoirs,a3Dgeologicalmodelissetupusingseismicreflectionprofilestodescribethestructuresindetail(Figure1).Implicit3Dgeologicalmodelingprovidesapowerfultoolextrapolatecomplexfaultgeometriesderivedfrom2Dcrosssectionssuchasseismicprofilesandboreholedatatounknownpartsofthemodel,(e.g.RenardandCourrioux,1994).

Figure1:Preliminary3DModeloftheFaultNetworkatSoultz

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sThegeneralaimofthisstudyistoinvestigatethedistributionandformationofpermeabilityinthesehorststructures.Thiswillbeaccomplishedbymeshingthegeological regional3Dmodel fornumerical simulation.Ageodynamicmodelwillestablishedusingdifferentobservablesinthehorststructure,suchasthetemperatureanomaly,distributionoffaults,frac-turesandporosity,andthespecificmorphologicalsettingofahorstintheRhinevalley.Inasecondpartoftheproject,theinfluenceoftheorientationsmall-scalestructuressuchastheinternalmorphologyoffaultsonthefluiddynamicswillbeinvestigated.

REFERENCESBächler,D.,Kohl,Th.,Rybach,L.2003: Impactofgraben-parallel faultsonhydrothermalconvection -RhineGrabencase

study,PhysicsandChemistryoftheEarth,28,431-441.Renard, P.&Courrioux,G. 1994: "3-Dimensional geometricmodelingof a faulteddomain – the soultz-horst example

(Alsace,France)."Computers&Geosciences20(9):1379-1390.Schill, E.,Kohl, Th.,Wellmann, J. F. 2007: First resultsof theGeothermalResourceAnalysis inRhineland-Palatine, First

EuropeanGeothermalReview,GeothermalEnergyforElectricPowerProduction,October29-31,2007,Mainz,RhinelandPalatinate,Germany,AbstractsandPapers.

Schill,E.,Kohl,Th.,Baujard,C.,Kümmritz,J.,Wellmann,J.F.,2009:GeothermischerRessourcenatlasRheinland-Pfalz–Süd-undVorderpfalz.Report for theMinisterium fürUmwelt, ForstenundVerbraucherschutzRheinland-Pfalz, February,2009

8.3

Converting geological maps to vector datasets – Completing the National Geological Information

BalandPauline1&MöriAndreas1

1Federal Office of Topograpy swisstopo, Swiss Geological Survey, Seftigenstrasse 264, CH-3084 Wabern (Pauline.Baland-Renaud@swisstopo.ch)

TheSwissGeologicalSurvey(SGS)hasbeenproducinggeologicalmapsformorethan80years.TheirmainproductistheGeologicalAtlasofSwitzerland1:25'000(GA25).About50%ofthe220mapsheetsarefinishedandavailableinprintedandraster formats.Because thedemand forgeologicalvectordatahas increased strongly in recentyears, theSGS started toconverttheexistinggeologicalmapsintovectordatasets.

Dependingontheavailablesourceformat,oneoftwotechniquesisappliedtoconvertmapdataintoaGIS-format:

1) "MethodSion":Mapsavailable"only"inrasterformataredirectlyvectorisedinaGISenvironment.ThismethodwasdevelopedincooperationwiththeCentrederechercheenenvironnementalpin(CREALP)andtheactualtransfor-mationisperformedattheInstituteofGeomaticsandRiskAnalysisoftheUniversityofLausanne(IGAR)

2) "MethodVallorbe":Forrecentlyprintedmaps,AdobeIllustratorvectordataareavailable.Usingthesedataasaninput,"cartographic"dataareconvertedbytheaidofAvenza-MapublishertoattributedGIS-data.ThismethodisbeingdevelopedincollaborationwiththeSwissGeotechnicalCommission.

Bothmethodsareequivalentandarebasedonthegeologicaldatamodel,which isdeveloped inaseparatedproject (cf.Straskyetal.,thisvolume).Presentlyabout40%oftheexistingmapsoftheGA25(about50maps)werealreadyconverted.The"MethodSion"isnowimplementedbytheSGSalsoonotherpublishedmapswithdifferentscales.

SincetheSGSisnotabletosolelyfinancetheentirevectorisation,collaborationwithcantonsandinsurancecompanieshasbeeninitiated.Thismodeloffinancingworksquitewell,but,theSGSissubjecttotheprioritiesandresourcesofthespe-cificinstitutions.

Theoverallobjectiveof theSGS is tobuildaGeographic InformationSystem,whichprovides seamlessvectordatasetsofSwitzerland.Toreachthisaim,oneofthemaintaskswillbetogeometricallyandsemanticallyharmonisetheexistingvectordatasets.Thedifficultyofthistaskisincreasedbythevarious"quality"ofeachmap.Duringthe80-yearperiodofmappro-duction,thescientificknowledgehaschangedmanytimesandthereforethegeologicalinterpretationinthemapsaswell.Thetwomethodsarecurrentlyinfulluseandwellintegrated.Furthermore,constantupdatingoftheappliedmethodsen-sureshighdataquality.ThesedataarethebasisforthefuturegrowthoftheGeologicalInformationSystemofSwitzerland.

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Risk, measured risk aversion and individual characteristics

BaruffiniMoreno1

1Istituto Scienze della Terra IST-SUPSI, C.P. 72, CH-6952 Canobbio (ist@supsi.ch)

Riskanduncertaintyplayakeyroleineverydaylife:duringthepastseveralyearstheworldhaswitnessedsomeunprece-denteddisastersthatheavilycrushedsocietiesandlivingsystems.Individuals,institutions,andcommunitieshavetheabilitytodeflect,withstand,andreboundfromseriousshocksintermsofthecourseoftheirordinaryactivitiesorthroughingenuityandperseveranceinthefaceofacrisis.Isthereforeveryimportanttorecordandestimateriskaversion.

Whatistheimpactofcontextsonwillingnesstotakerisks?Howdoriskperceptionchangeshazardperceptionandtherebyrisk?

Unfortunatelythistaskisstillextremelydifficult:theindividualbehavioursdependsonalotofcharacteristicswithelicita-tionbias,preferencereversalandsoon.Usingaquestionthatasksaboutwillingnesstotakerisks(onaelevenpointsscale)weperformedsometestsonacohortcomposedbyyoungstudents.Usingquestionsabouttheirriskperceptioninspecificdomains,ascardrivingortraining,weanalyzedtheriskaversionandtheimpactofcontext.Wefinallyvalidatedresultsthoughalotteryquestionforanhypotheticinvestment.

Aimingtoimproveourunderstandingofriskperceptionandhowtorepresentitwefoundsomeevidences:distributiontotakerisksisquiteheterogenicacrossindividuals,femalesandoldagedpeoplearemoreriskaversethanmalesandyoungpeople,ageneralriskquestioncanactuallybeusedtomodelageneralriskbehaviour.

Theinitialresults,althoughstillrough,canbeveryusefultorepresentactualriskaversionacrossasocietyoragroupandcanbeusedtovalidateriskmanagementstudiesinthefieldofnaturalortechnologicalhazards.

REFERENCESCaliendo,M.,Fossen,F.andKritikos,A.2007:Riskattitudesofnascententrepreneurs:newevidencefromanexperimentally-

validatedsurvey.DiscussionpapersDIWBerlin.DarmstadtUniversityofTechnology,InstituteWAR;UniversityofBern,DepartmentofGeography,AppliedGeomorphology

andNatural Risks, Spatial planning and supporting instruments for preventive floodmanagement, TechnischeUniversitätDarmstadt,Darmstadt/Bern

Dohmen,T.etal.2005:Individualriskattitudes:newevidencefromalarge,representative,experimentally-validatedsurvey.DiscussionpapersDIWn.511,Berlin.

Hartog,J.,Ferrer-i-Carbonell,A.andJonker,N.2002:Linkingmeasuredriskaversiontoindividualcharacteristics.KYKLOSVol.5-2002-Fasc.1,3-26.

8.5

Systematic analysis of natural hazards along infrastructure networks using a GIS-tool for risk assessment

BaruffiniMirko1&ThüringManfred1

1Istituto Scienze della Terra IST-SUPSI, C.P. 72, CH-6952 Canobbio (ist@supsi.ch)

Infrastructurevulnerability isaraisingtopicof interest inthescientific literatureforboththegeneral increaseofunex-pectedeventsandtheextremelyimportancethatcertainlinksplayinsolvingeverydayneeds.Infact,duetothetopographicalconditionsinSwitzerland,thehighwaysandtherailwaylinesarefrequentlyexposedtonaturalhazardsasrockfalls,debrisflows,landslides,avalanchesandothers.

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sTomitigatetheseassociatedlosses,bothtraditionalprotectivemeasuresandland-useplanningpoliciesaretobedevelopedandimplementedtooptimizefutureinvestments.Thisasksforahighlevelofsurveillanceandpreservationalongthetransalpinelines.Efficientprotectionalternativescanbeobtainedconsequentlyconsideringtheconceptofintegralriskmanagement.

Riskanalysis,asthecentralpartofriskmanagement,hasbecomegraduallyagenerallyacceptedapproachfortheassess-mentofcurrentandfuturescenarios(Loat&Zimmermann2004).Theprocedureaimsatriskreductionwhichcanberea-chedbyconventionalmitigationononehandandtheimplementationofland-useplanningontheotherhand:acombina-tionofactiveandpassivemitigationmeasuresisappliedtopreventdamagetobuildings,peopleandinfrastructures.

WithaGeographicalInformationSystemadaptedtorunwithatooldevelopedtomanageRiskanalysisitispossibletosurveythedataintimeandspace,obtaininganimportantsystemformanagingnaturalrisks.

Asaframework,weadopttheSwisssystemforriskanalysisofgravitationalnaturalhazards(BUWAL1999).Itoffersacom-pleteframeworkfortheanalysisandassessmentofrisksduetonaturalhazards,rangingfromhazardassessmentforgravi-tationalnaturalhazards,suchaslandslides,collapses,rockfalls,floodings,debrisflowsandavalanches,tovulnerabilityas-sessmentandriskanalysis,andtheintegrationintolanduseplanningatthecantonalandmunicipalitylevel.Theschemeislimitedtothedirectconsequencesofnaturalhazards.

Thus,wedevelopasystemwhichintegratestheproceduresforacompleteriskanalysisinaGeographicInformationSystem(GIS)toolbox,inordertobeappliedtoourtestbed,theAlps-crossingcorridorofSt.Gotthard.ThesimulationenvironmentisdevelopedwithinArcObjects,thedevelopmentplatformforArcGIS.ThetopicofArcObjectsusuallyemergeswhenusersrealizethatprogrammingArcObjectscanactuallyreducetheamountofripetitivework,stream-linetheworkflow,andevenproducefunctionalitiesthatarenoteasilyavailableinArcGIS.WehaveadoptedVisualBasicforApplications(VBA)forprogrammingArcObjects.BecauseVBAisalreadyembeddedwithinArcMapandArcCatalog,itiscon-venientforArcGISuserstoprogramArcObjectsinVBA.

Ourtoolvisualisestheobtaineddatabyananalysisofhistoricaldata(aerialphotoimagery,fieldsurveys,documentationofpastevents)oranenvironmentalmodeling(estimationsoftheareaaffectedbyagivenevent),andeventsuchasroutenumb-erandroutepositionandthematicmaps.

AsaresultofthissteptherecordappearsinWebGIS.Theusercanselectaspecificareatooverviewprevioushazardsintheregion.Afterperformingtheanalysis,adoubleclickonthevisualisedinfrastructuresopensthecorrespondingresults.Theconstantlyupdatedriskmapsshowallsitesthatrequiremoreprotectionagainstnaturalhazards.

Thefinalgoalofourworkistoofferaversatiletoolforriskanalysiswhichcanbeappliedtoothersituations.TodayourGISapplicationmainlycentralisesthedocumentationofnaturalhazards.Additionallythesystemoffersinformationaboutna-turalhazardattheGotthardline.TheinitialresultsoftheexperimentalcasestudyshowshowusefulaGIS-basedsystemcanbeforeffectiveandefficientdi-sasterresponsemanagement.InthecomingyearsourGISapplicationwillbeadatabasecontainingallinformationneededfortheevaluationofrisksitesalongtheGotthardline.OurGISapplicationcanhelpthetechnicalmanagementtodecideaboutprotectionmeasuresbecauseof,inadditiontothevisualisation,toolsforspatialdataanalysiswillbeavailable.

Wepresenttheconceptandcurrentstateofdevelopmentandanapplicationtothetestbed,theAlps-crossingcorridorofSt.Gotthard.

REFERENCESBründlM.(Ed.),2009:RisikokonzeptfürNaturgefahren-Leitfaden.NationalePlattformfürNaturgefahrenPLANAT,Bern.

416S.BUWAL 1999: Risikoanalyse bei gravitativenNaturgefahren -Methode, Fallbeispiele undDaten (Risk analyses for

gravitationalnaturalhazards).Bundesamt fürUmwelt,WaldundLandschaft (BUWAL).Umwelt-MaterialenNr. 107,1-244.

Loat,R.&Zimmermann,M.2004:LagestiondesrisquesenSuisse(RiskManagementinSwitzerland).In:Veyret,Y.,Garry,G.,MeschinetdeRichemont,N.&ArmandColin (eds) 2002:ColloqueArchede laDéfense22–24octobre2002,dansRisquesnaturelsetaménagementenEurope,108-120.

MaggiR.etal,2009:Evaluationoftheoptimalresilienceforvulnerableinfrastructurenetworks.Aninterdisciplinarypilotstudyonthetransalpinetransportationcorridors,NRP54“SustainableDevelopmentoftheBuiltEnvironment”,ProjektNr.405440,FinalScientificReport,Lugano

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Challenges for geological surveys in geological 3D model building and validation

BaumbergerRoland&OesterlingNils

Swiss Geological Survey, Federal Office of Topography swisstopo, Seftigenstrasse 264, CH-3084 Wabern, SwitzerlandContact: roland.baumberger@swisstopo.ch

Geological3Dmodelsarealwayswrongtosomeextent.Therefore,whilebuildingupgeological3Dmodels,specialemphasishastobemadeoneffortsconcerningdataqualitymanagement,dataassessmentandmodelvalidation.Inthiscontext,theSwissGeologicalSurvey(SGS)assumesaspecialposition,sinceitsmissionregardinggeological3Dmodellingislegallybased.Accordingtothefederallawongeoinformation(GeoIG)andthefederalactfortheSGS(LGeolV),theSGShastoprovidegeo-logicaldataandinformationtothefederaladministrationandtothirdpartiesinanalogueordigitalformats.Additionally,theSGSisinchargeofofferingextensivegeologicaldataandthereforewantstobuildupnational,regionalandlocalgeolo-gical3Dmodelsatdifferentresolutionsandscales.

WhileproducingtheGeologicalAtlasofSwitzerland,theSGSisgenerallycommittedtoahighlevelofqualityinordertomeetthescientificandcartographicstandardsthatareeithersetbytheSGSitselfordemandedbythepartnersandcusto-mers.Regardingthegeological3Dmodelling,itistheresponsibilityoftheSGStobuildupvalid,geologicallycorrectandconsistent3Dmodels.Furthermore, this levelofqualitymustcomplywiththequalityrequirementsof themapproduc-tion.Drivenbythisguidelines,theSGSfacesseveraltechnicalandorganisationalchallenges:(1)therequiredinputdatafor3Dmodellingiswidelydistributedanditsexistenceissometimesuncertain,(2)thequalityoftheexistinginputdatadependsontheproducerandhashighlyvariableresolution,accuracy,conceptualgeologicalbackgroundandreliability,(3)thepur-poseandscaleofthedatasamplingvaries,(4)differentconceptsfordatamanagement(acquisition,storage,usage)havetobeintegratedand(5)thetechnicalandconceptualbackgroundsofalreadyexisting3Dmodelsarediverging.

Facingthesechallenges,onehastobeawarethatthequality,informationdepthanddensityaswellastheconsistencypro-videdbyageological3Dmodelshowadirectcorrelationtothequalityofthedatasources.Theinformationprovidedcanonlybeasgoodasthequalityoftheinputdata.Asaconsequence,theSGShastoperformextraeffortsinthefieldsofdatastandardisationandharmonisationaswellasqualitymanagement.Thesebasicstepswillbecoveredbythedatamodelforgeologicaldata,whichiscurrentlybeingbuiltbytheSGS.Fromthescientificpointofview,itisnecessarytousethelatestprovengeologicalconceptsandtofollowresearchtrendsinordertosuccessfullyprovidethemostaccurategeologicalmodelsinthreedimensions.Regardingthetechnicalaspects,theSGSmustuseupdatedapproachesregardingmodellingconcepts,methodsandwork-flows,datastorage,dataexchangeability,modelvalidationanddistributionofthe3Dmodels.Thechallengeslistedabovehaveleadtotheconceptionofthegeneralarchitectureofgeological3DmodellingattheSGS(ELFERSetal.,2004,adaptedbySGS).Followingthisapproach,thelargenumberofinputdataisfirstofallstoredinappro-priate storage facilities. Secondly, thesedata are checked, adapted, interpreted, (re-)formatted, assessedandharmonised.Thirdly,thepreparedandstandardiseddataarefedintothegeological3Dmodellingsoftware,anda3Dfaultmodelanda3Dsurfacemodelaredevelopediteratively.Fourthly,thesetwomodelsarestoredasthebasicgeological3Dmodel,fromwhichalargenumberofspecializedandspecific3Dmodelsmaybederived(Figure1).

Toperformtheaforementionedprocess,theSGSappliestheMovesoftwaresuitefromMidlandValleyExploration.ModelvalidationisalsoperformedwithMove.Byprovidingvarioustoolsformodelbuildingandvalidation,theMovesoftwareallowstheSGS(1)tobuildupvalid3Dmodels,(2)toachievegeologicalconsistencyinthreedimensionsandthroughtimeaswellas(3)toaccountfortheuncertaintyregardingthedataquality.UsingMove2009.2,theSGSisabletomanagethescientific,organisationalandtechnicalchallengesitisfacinginthefieldofgeological3Dmodelling.

REFERENCESELFERS,H.etal.(2004):Wegezur3D-Geologie,Krefeld,2004MOVE2009,MidlandValleyExploration,Glasgow(UK),http://www.mve.com

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DATA ACQUISITION DATA PREPARATION GEOLOGICAL3D MODELLING

GEOLOGICAL3D BASIS MODEL

drill holes cross section

surfaces maps

geotechnical geophysical

3D modelsart. bodiesother

data check

reformatting

interpretation / adaptation

�rst /re-assessment

data storage in temporarysources harmonisation

& standardisation

source data

generation

import

integrationplatform

3D geology

existingdata&3Dmodels

3D fault model+

3D surface model

Figure1:Thearchitectureoftheprocessofgeological3DmodellingattheSGS(basedonELFERSetal.(2004),adaptedbySGS)

8.7

Overview of available geoscience data in Switzerland

BeresMilan&KühniAndreas

Swiss Geological Survey, Federal Office of Topography swisstopo, Seftigenstrasse 264, CH-3084 Wabern (milan.beres@swisstopo.ch)

Geoscienceinformationismadeavailableforthepurposesofrecognizingandreactingtoenvironmentalproblems,evalua-tingconstructionprojectsandnaturalresources,planningexcursionsandsimplyenjoyingnature.Manyusersofthisinfor-mation are also producers and include various federal and state agencies, the energy industry, universities and privateconsultingoffices.InSwitzerlandtheproductionofgeosciencedataandinformationishighlydecentralised,signifyingawidevarietyofformats,qualities,accessibilitiesandvisualisations.Furthermore,theuserscommonlydonotknowwhichdatasetsareavailable,wheretheycanbeobtainedandwhatpurposestheyallserve.

Tomeetthechallengesmentionedabove,theSwissGeologicalSurveyanditscollaboratorsareplanningtopublishanover-viewofallavailabledatasetsinSwitzerlandthatarerelevanttoearthscience(Beresetal.2008,2009).Thisoverviewisaimedatadiverseaudience(e.g.politicians,interdisciplinaryprofessionals,researchers,teachers,students,hobbygeologists,tou-rists)andhasthefollowinggoals:

• Togiveanoverview:eye-catchingfiguresandshorttexts,whichdescribethedatasettheory,purpose,sourceandproduc-tionmethods,areenvisagedforthepublication.

• Tosensitisethepublic:asmanypeopleaspossibleshouldbemadeawareofhowtheearthsciencestouchoureverydaylife.

• Toboostpublicrelations:withsuchapublication,producersofgeosciencedataandinformationcanadvertisetodecisi-onmakersandthegeneralpublic.

• Tobuildanetwork:theresultsoughttopromotecontactsandcollaborationamongproducersandusersofgeosciencedataandinformation.

• Tointegratedatasets:anoverviewservesasthebasis for integratingdatasets inthegeological informationsystemofSwitzerland(Oesterlingetal.2009).

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Recentpublications(Jackson2004;Hofmann&Schönlaub2007)showthatsimilargoalsarebestachievedbycreatingaprin-ted,easilyunderstandabledocument.

Productionoftheoverviewcomprisesclearlydefinedtasks.Contactingthedataproducersandestablishingcollaborationarepartoftheinitialphase.Thisphasealsoincludesdeterminingexactlywhohaswhatandchoosingtheoptimalrepresen-tationforaparticulartheme.Presently,theoverviewcontains54themes,whicharecategorisedintothefollowingfourbasicgroups:

• Earthfundamentals,e.g.tectonics,stratigraphy,bathymetry,soiltypes,magneticfield,gravityanomalies,topography.• Constructionandresources,e.g.hydrogeology,landuse,geothermalenergy,varioustypesofrockquarries.• Hazardsandenvironment,e.g.earthquakes,massmovements,radonrisk,groundwaterquality.• Geotourismandgeologicalheritage,e.g.showcaves,thematichikingtrails,geotopes.

Thelayoutstipulatestwopages(A4portrait)foreachtheme.Ontheleftpage,thedataset,insomecasesgeneralised,isover-lainonamapoftheSwissnationalboundaryandmajorlakes.Inthecaseofpointdata,asimplifiedtectonicmapservesasanadditionalbackground.Logosandanextractofamoredetaileddatasetoranexplanatoryfigurearelocatedonthelowerhalfofthispage.Ontherightpage,thetitle,thetheme’scategory,explanatorytext,datasources/ownershipandacarefullychosendiagramorphotographareincluded.SinceSwitzerlandisamultilingualcountry,acolumnoftextinGermanandasecondcolumnofthesametextinFrencharenecessary.ProvidingasummaryofthetextinEnglishwouldbeparticularlyhelpfulforinternationalreaders.

Insummary,therearemanyreasonstoproduceanattractiveandinformativeoverviewoftheavailablegeosciencedatasetsinSwitzerland.Suchanoverviewnotonlywillillustratethehighlightsofthecountry’suniquenaturalfeatures,butitwillalsosensitiseabroadaudienceandstrengthennetworkingamongmembersoftheSwissgeo-scene.ThesereasonsmakeitanimportantcontributiontotheplannedgeologicalinformationsystemofSwitzerland.

REFERENCESBeres,M.,Kühni,A.&Schindler,U. 2008:Bringinggeothematicmaps to thepublic.Abstract of the33rd International

GeologicalCongress,August6-14,Oslo,SessionIEI-14.Beres,M.,Kühni,A.&Schindler,U.2009:ThegeothematicatlasofSwitzerland:Anoverviewofgeologicallyrelevantmaps

foreveryone.ExtendedAbstractofthe6thEuropeanCongressonRegionalGeoscientificCartographyandInformationSystems,Vol.II,June9-12,Munich,233-235.

Hofmann,T.&Schönlaub,H.P.(Eds.)2007:Geo-AtlasÖsterreich,DieVielfaltdesgeologischenUntergrundes.GBA,Böhlau,Vienna,112pp.

Jackson,I.(Ed.)2004:Britainbeneathourfeet.BGSOccasionalPublication4,Keyworth,Nottingham,120pp.Oesterling,N., Baumberger,R., Beres,M.,Kühni,A.&Kündig,R. 2009: Thegeological information systemSwitzerland.

ExtendedAbstractofthe6thEuropeanCongressonRegionalGeoscientificCartographyandInformationSystems,Vol.I,June9-12,Munich,254-256.

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Exposure-based risk assessment for tephra accumulation: the example of Cotopaxi volcano (Ecuador)

BiassSébastien1,ParmigianiAndrea1,Dell’OroLuca2,SenegasOlivier2&BonadonnaCostanza1

1Départment de Minéralogie, Rue de Maraîchers 13, CH-1205 Genève, Switzerland (biasse3@etu.unige.ch)2UNOSAT, International Environment House, Chemin des Anémones 11-13, CH-1219 Châtelaine, Switzerland

Tephra isamajorproductofexplosiveeruptionsand itsdispersalandaccumulationcancausesignificantdisruptionofhumanactivities.Duetoitscapacitytoreachwidespreadareas,variouseffectsonthesurroundingcommunitiesneedtobeconsidered.Thesecanbeclassifiedasphysicalaspects(e.g.collapseofbuildings,breakdownofelectricalsystems),economi-calaspects(e.g.damagetocrops,deathofcattle,effectsontourism),functionalaspects(e.g.blockageofroads,airportsandairtraffic)andhealthaspects(e.g.breathingoffineparticles,eyeandskinirritation)(e.g.Blong1984).

Duetotheconstantincreaseofpopulationdensityaroundvolcanoes(SibertandSimkins1994),governmentsandplannersrequireknowledgeofboththeexpectedhazardandtheelementsatriskinordertoproduceefficientland-useandemergen-cyplanningprioracrisis.Inthisframework,wepresentanewmethodologydesignedtohelpdecision-makerstodealwithtephrafallout.First,hazardmapsarecompiledbasedontheTEPHRA2analyticalmodel (Bonadonnaetal.2005).Second,exposure-basedriskmapsareproducedbycombininghazardmapsandurbanelementsthroughGIS-basedfuzzymodelling.Giventhatpreciseandup-to-dategeographicaldataaretypicallydifficulttoaccess,webasedourexposureassessmentonfreeandglobaldatasets,whichincludeinformationonbuildings,vegetation,agriculture,airports,roadnetworkandcriticalinfrastructures.

Wehave testedourmethodologyonCotopaxivolcano (Ecuador),which is located60kmsouthofQuitoand threatensahighlypopulatedvalley.Wehaveproducedexposure-basedriskmapsaccountingfordifferenteruptionmagnitudestypicalofthelast2000yearsofvolcanicactivityofCotopaxivolcano.

Figure1.Situationmapwithmainpopulatedareasandprincipalvolcanoes.

REFERENCESBonadonna,C.,Connor,C.B.,Houghton,B.F.,Connor,L.,Byrne,M.,Laing,A.,Hincks,T.K.2005:Probabilisticmodellingof

tephradispersal:HazardassessmentofamultiphaserhyoliticeruptionatTarawera,NewZealand,JournalofGeophysicalResearch,110,B03203,doi:10.1029/2003JB002896.

Blong,R.J.1984:Volcanichazards:asourcebookontheeffectsoferuptions.AcademicPress,Sydney.Simkin,T.,Siebert,L.1994:Volcanoesoftheworld,GeosciencepressInc.inassociationwithSmithsonianInstitution,1-349.

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GIS-based method for groundwater management and protection: geo-types serving 3D applications

BilgotSéverine1,ParriauxAurèle1

1 EPFL ENAC IIC GEOLEP, Station 18, CH-1015 Lausanne (severine.bilgot@epfl.ch)

Sustainablemanagementofundergroundnaturalresourcesismoreandmoreaworthwhiletopic.Inparticular,worryingaboutgroundwaterprotectionbecomes imperative. Taking intoaccount the increaseof incompatibilitiesbetweenwaterconservationandtheuseofotherundergroundresources,theGeoleplaboratorybroughtoneofitsresearchaxesaroundtonewmethodsforgroundwaterresourcesassessmentandmanagement.Asthesemethodshavetobeastransparentaspossible,weimplementedaGIStousestandardizedprotocolstorealizenewmapsofgroundwaterprotectionareasandresourcesindexand,inasecondstep,todeterminewhereitshouldbepossibletoinstallgeothermalheatpumpswithoutendangeringdrinkablewaterresources(OFEV,2009).Thesemethodologies arebothbasedon theuseof thegeotypes,which is anewclassification for geological formations(ParriauxandTurberg,2007);itinvolvestheuseofgeneticstandardsforloosematerial(e.g.lodgementtill)andlithologicstandards for hard rock (e.g. sandstone). Forty-one geotypes and their properties in relation to groundwaterswere thusintegratedinaGISandcompletedwithgeophysicalandboreholesdata.TheachievementofthenewgroundwaterprotectionareasmapsiscurrentlyinthepipelineforthewholecantonofVaud,whiletheimplementationofthenewmethodologyforgeothermalheatpumpadmissibilitymapping(riquiringthebuildingofa3Dgeologicalmodel)isstillbeingtested.

REFERENCESOFEV:Exploitationdelachaleurtiréedusoletdusous-sol.Aideàl’exécutiondestinéeauxautoritésetauxspécialistesde

géothermie.L’environnementpratiquen°0910.Officefédéraldel’environnement,Berne,51p,2009.A.ParriauxandP.Turberg,Lesgéotypes,pourunereprésentationgéologiqueduterritoire,Tracés,Nr.15/16,pp.11-17,2007.

8.10

A pseudo-genetic approach for the stochastic generation of karstic networks

AndreaBorghi1,PhilippeRenard1andSandraJenni1

1 University of Neuchâtel, Stochastic Hydrogeology Group, 11 Rue Emile Argand CP 158 2000 Neuchâtel, Switzerland. andrea.borghi@unine.ch, philippe.renard@unine.ch1 Schlumberger Water Services, Immeuble Madeleine D, 92057 Paris la Défense Cédex France, sjenni@la-defense.oilfield.slb.com

Modellingkarstsystemsisachallengebecauseoftheirextremespatialheterogeneitywhichstronglyinfluencesthehydrau-licandsolutetransportbehaviour.Forthisreasonitisnecessarytotakeintoaccountboththeconduitsystemandthema-trix.Itbecomesthennecessarytodevelopmethodstogeneraterealistickarsticconduitsystemseveniftheirpositionisnotknownaccurately.Themethodpresentedinthispostersimulateskarstconduitsystemstakingintoaccountononehandfieldobservations(thatmaybeindirect)andontheotherhandtheconceptualgeologicalknowledgecontrollingtheconduitstructuresthatmightbedisplayedinagivengeologicalenvironment.

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sThesuggestedmethodologyisbasedonthefollowingsteps:

1. 3Dregionalgeologymodelling:thepositionofthecarbonateformationsin3Dwithrespecttotheothernonkarstifia-bleformationscontrolsthelocationswherethekarsticnetworkcandevelop;

2. simulationoftheinternalpropertiesofthekarstifiableformation(e.g.fracturation,stratificationjoints):theinternalpropertiesoftheformationstronglyinfluencethelocalshapeoftheconduits;

3. identificationoftherecentorpaleohydrodynamiccontrolsataregionalscale:thisisachievedbyidentifyingrechargeanddischargemechanisms,locationofthepunctualordiffuseoutletsandinlets(springs,dolines,shallow-holesetc),asitisknownthatthetypeofrechargeordischargecontrolsthetypeofnetworkthatcandevelop;

4. foreachpossiblephaseofkarstification:a.extrapolationofthecorrespondingpaleobaselevelandsimulationofthekarsticconduitsfromthetopographic

surfacetowardthebaselevelusingafastfronttrackingmethod(levelset)andrandomwalkermethod;b.usingthesamefronttrackingmethod,connectthepathsthathavebeencreatedintheunsaturatedzonetothe

outletthroughthesaturatedzone;inbothstepsaandb,thepathsfollowthegeologicalstructureandarecontrol-ledononehandbythelocalheterogeneitiesgeneratedinstep2andontheotherhandbytheflowconditions;

Thefinalresultisa3Dkarsticnetworkthatiscontrolledbytheregionalgeology,thelocalheterogeneitiesandtheregionalflowconditions.Thenetworkcanthenbeusedtomodelflowandtransport.Severallevelsofrandomnesscanbeconsidered(uncertaintyonlargescalegeologicalstructures,localheterogeneity,positionofpossibleinletsandoutlets,phasesofkarsti-fication)allowingtoinvestigatetheuncertaintyonthestructureofthenetworkanditsconsequences.

Comparedtoothertechniques,thismethodpresentstheadvantagetobefast,toaccountforthemainfactorscontrollingthe3Dgeometryofthenetwork,andtoallowconditioningfromfieldobservationswhenavailable.

Figure1.a)3Dgeologicalmodel(volumeview)b)3Dkarsticnetworkinaregularmeshc)2Dkarsticnetworkin2Dregularmeshd)3D

geologicalmodel(crosssections)

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SAPHYR, the Swiss atlas of physical properties of rocks

BruijnRolf1,ZapponeAlba1,BurliniLuigi1,TripoliBarbara1,HolligerKlaus2,BurgJean-Pierre1&KisslingEduard1

1ETH, Department of Earth Sciences, Sonneggstrasse 5, CH-8092 Zürich (rolf.bruijn@erdw.ethz.ch)2UNIL, Institute of Geophysics, Amphipole – UNIL SORGE, CH-1015 Lausanne

Since2006,amulti-yearprojectrunsundertheumbrellaoftheSwissGeophysicalCommission(SGPK),withtheaimtodigi-tizeallexistingdataonphysicalpropertiesofrocksandtolinkthemusingageographicalframe(GIS).

Theaimistomakethosedataaccessibletoawidepublicsuchasinindustrialcontext:constructionandengineeringcom-panies,geothermalinvestigationandextraction,etc.,forlanduseplanners:waterresource,wastedisposalnaturalhazardetc.;andfinallyforacademicstudies(integratedgeophysical,geologicalandpetrologicalresearch,researchinpetrophysicsetc).

Thephysicalpropertiesofinterestaredensityandporosity,seismic,magnetic,thermalproperties,permeability,electricalproperties.Forthetimebeingdatafromliteraturehasbeencollectedextensivelyforseismicpropertiesandonlypartiallyfortheotherphysicalproperties.Herewepresentthefirstoutput:amapofSwitzerlandwithsamplelocationscombinedwithcontouredvaluesofVp,seefigure1,extrapolatedtoroomconditionsfromthehighpressurelaboratorymeasurements(matrix or crack free properties). The values are reported as contours and colour-coded. A sample locationmap for Vsmeasurementsisalsopresented.Vsanalysisanddataprocessingisongoingworkinprogress.Weexpecttopublishthere-sultsontheAtlasofSwitzerland(swisstopo),hopefullybytheendof2009.

Figure1.MapofSwitzerlandwithcompressionwavevelocityvariations,originatingfromlithologicalheterogeneities.Vpcolourgroups

werederivedfromindividualVpmeasurementsontypicalrocktypesfoundintheAlps.Locationsofrocksamplesaremarkedbyablack

star.Literaturevaluesforwaterandiceareusedtorepresentlakesandglaciers.Mappolygonsweretakenfrom‘DigitaleGeotechnische

KartederSchweiz1:500000’,producedbySGTK.

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IstSOS: Sensor Observation Service in Python

MassimilianoCannata,MilanAntonovic

Istituto Scienze della Terra, IST-SUPSI CH-6952 Canobbio, Tel. +41 (0)58 666 62 09

Approvingthenewfederallowaboutgoinformation(RS510.62),theSwitzerlandgaveagreatimpulsetotheestablishmentofanationalspatialdatainfrastructure,whichinagreementwiththeEuropeanCommissiondirectiveINSPIRE(2007/2/CE),willbebasedongeo-services.

Thisapproachhastheadvantagetogive,localadministrationanddatamaintainer,thefreedomtochoosethedesiredfor-mats,softwareanddatamodelbutimposetheprovisionoftherequireddatathroughoutastandardWebservice.Thissim-plifytheprocessofdatagathering(theusergetthedataondemandandnotanymorethemaintainerprovidethemonre-quest)providingthebasisforarealandpracticalaccomplishmentofthesomuchdesireddatainteroperability.Geoscientistsareparticularlyinterestedinthistypeofinteroperability: infactaconsiderablyexpensivecommonphaseofmostofthegeo-projectsinvolvestheacquisitionandintegrationofdatainordertobefurtheronprocessedandanalyzed.

WhilesomeoftheGeographicalWebServices,likeWMSandWFS,aretodaywidelydiffusedandapplied,otherslikeSOS(SensorObservationService)arestillaworkinprogressandneedsomerevisionfortheircorrectapplication.

InordertoinvestigateandprovidesuchakindofSDIforscientists,theIST(IstitutoScienzedellaTerra)isdevelopinganew,fullyOGCcompliant,SOSinPythonlanguagethatisabletodistributeobservationdataandtoprovideaprocessingenviron-mentfordevelopingresearches.

Duringthedevelopmentphaseaseriesofconsiderationsandpracticalsolutionshasbeenstudied.Asaconclusion,atthisstageofdevelopment,theauthorscanunderlinethefollowingopenissues:

• ThexmlschemesusedintheSOSarenumerous,nestedandofteninterchangeable.ThisleadstoanSOSresponsesvari-able,dependingonthesoftwareandtheinterpretationthatthedeveloperapplied,andthereforeadifficultautomaticparsing.

• TheSOSdoesnotprovidepreciseinformationononthologiesleadingtomisunderstandingdefinitions.• Thestandardsdonottakeintoaccountthetypeofobservationaccordingtothesensorlocation(in-situorremote),the

observationtype(point-wiseordistributed),andtheobservationdynamic(staticormobile).

Tooverridethislacks,wearedevelopingasystemthatinternallyconsidertheseissuesstillconservingthecompliancewiththecurrentstandard.Moreinformationareavailableat:http://istgeo.ist.supsi.ch/site/projects/istsos

REFERENCES510.62,Loifédéralesurlagéoinformation,http://www.admin.ch/ch/f/rs/510_62/index.htmlOpenGIS®SensorObservationService(SOS),http://www.opengeospatial.org/standards/sos

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Modeling heterogeneous geological reservoirs using multiple-point statistics simulations

ComunianAlessandro1,StraubhaarJulien1,RenardPhilippe1,RolandFroidevaux2

1Centre for Hydrogeology (CHYN), University of Neuchâtel, Emile-Argand 11, CH - 2009 Neuchâtel (alessandro.comunian@unine.ch, julien.straubhaar@unine.ch, philippe.renard@unine.ch)2Ephesia Consult, 9, rue Boissonnas CH - 1227 Geneva, Switzerland (roland.froidevaux@ephesia-consult.com)

3Dmodelsofheterogeneousgeologicalreservoirsareimportanttoolstounderstandandmanageaquifers.Whenaconceptu-algeologicalmodel(analoguesite,trainingimage)ofthestructuresisknown,multiple-pointstatistics(MPS)(Strebelle,2002,Mariethozetal.,2009)canbeusedtosimulatethereservoirgeometryconstrainedtofieldobservations.ThebasicprinciplesofMPSsimulationsconsistsofasequentialprocessvisitingallnodesofthesimulationgrid.Foreachnode,aconditionalprobabilitydensityfunction(cpdf)iscomputedusingallpixelconfigurationswithinthetrainingimage(TI)andtheconfigurationcentredonthevisitednodeinthesimulationgrid.Thiscpdfisthensampledinordertodrawrandomlyafaciesintothevisitednode.

Inthiswork,weillustrateontwocasestudiestheapplicationofanewlydevelopedMPStechnique(Straubhaaretal,2009).Thecorrespondingsoftware(Impala)isparallelandcanaccountforthenonstationarityofthegeologicalformations.

Figure1.Left)TIofsize1501x501:deltaoftheLenaRiver(Russia)(ref.:Landsat7image,USGS/EROSprojectandNASALandsatproject);

right)Simulateddeltastructure(size1500x900)basedontheTIontheleft.

First,a2Dexamplewith3facies(channels,lakes,land)isconsidered.AsatelliteimageofapartoftheLenaRiverdeltaistakenasanaturalanalogue(TI,Figure1).TheMPStechniqueallowstosimulatesimilarstructureswithdifferentorienta-tions(Figure1)inaplacewherenodataareavailable.Thedistancetothecoast,rotations,andconditioningdata(insea)areusedtocontrolthenonstationarity.

MPSsimulationcanalsobeappliedtoreconstructthethree-dimensionalstructureofhighlyheterogeneoussedimentarydeposits.ThisisillustratedusingtheHertendataset(Bayer,2009).Thedatasetcontainssixparalleloutcropsof16by7metersrecordedduringtheexcavationofaquarryintheRhinebasinclosetoBasel;thefaciesdescribedinthesectionsareusedasconditioningdata.

Figure2.OnesimulationoftheHertenaquiferanalogueobtainedusingMPSandahierarchicalapproach.

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sAhierarchicalapproachisused:themainsedimentarystructuresaresimulatedwithordinaryKriging;insidetheselargescalestructures,smallscaleheterogeneitiesaresimulatedwiththeMPStechnique.Figure2displaysonerealizationofthe3Dheterogeneities.

ThetwocasestudiesdescribedaboveillustratehowtheMPStechniquecanbeusedtomodelrealisticnonstationaryandhighlyheterogeneousstructureswithsuccess.Thosemethodscanthenbeappliedtoevaluatetheimpactofthesehetero-geneitiesonphysicalprocessessuchasflowandtransportandthenhelptoimprovemanagementdecisionsinacontextofuncertainty.

REFERENCESBayer,P.2009:3-Dhigh-resolutioncharacterizationofasedimentarygravelbodyforuseinhydrogeologicalandreservoir

modeling,HydrogeologyJournal,submitted.Mariethoz,G., Renard, P.& Straubhaar J. 2009: Thedirect samplingmethod to performmultiple-points geostatistical

simulations,WaterResourcesResearch,submitted.Straubhaar,J.,G.Mariethoz,andP.Renard2009:Multi-pointreservoirmodeling,InternationalPatentnr.2009WO-EP053614.Strebelle,S.2002:Conditionalsimulationofcomplexgeologicalstructuresusingmultiple-pointsstatistics,Mathematical

Geology,34,1-21,2002.

8.14

Different resolutions for different topics - the geological 3D-model of the Basel region

DresmannHorst,ZechnerEric,HuggenbergerPeter&EptingJannis

Applied and Environmental Geology, Institute of Geology and Paleontology, Bernoullistrasse 32, CH-4056 Basel (Horst.Dresmann@unibas.ch)

DifferentproblemsrelatedtothesubsurfaceofanurbanareasuchastheBaselregionrequiredetailedanduptodateknowl-edge.Someofthemostimportantaddresstheuseofgroundwaterresourcesfordrinkingwaterandindustrialprocesses,theuseofgeothermalenergy(deepandshallow),theexplorationofnaturalresources(e.g.salt),constructionofinfrastructure(roads,railwaysorbuildingsinthesubsurface)andearthquakehazardevaluation.Eachofthemhasspecificneedsregardinga3D-modelofsubsurface.Inparticulartheyneeddifferentscalesofresolutiontoadequatelyrepresentrelevantsurfacesandvolumesofthedifferentthematicfields(e.g.geology,hydrology,geophysics).Thepresented3D-modeloftheBaselregionwascontinuallydevelopedinordertoaddressthespecificproblems.

Thegrowingcomplexityof3Ddatarequiresaclearanduptodatedatastorageconcept.Ideally,themodelshouldbeeasilyadjustablewithnewdataandaspatialextension,oralocalrefinementofthemodelshouldbepossibleatalltime.Therefore,theaimistodevelopaflexibletool,whichoffersthebasisforthetreatmentofthemostdiversequestionsin3Dspaces.

WithinthescopeofanINTERREGIVandaBFE(BundesamtfürEnergieSwitzerland)project,westartedtocompletelyrevisetheinitial3D-modelofBasel(Zechner2001).Themaingoaloftheseprojectsistoevaluatethepossibilitiesandrisksofthedeeperunderground(Geopotentiale),withafocusonissuesrelatedtotheuseofdeepgeothermalenergy,earthquakerisksandthesequestrationofcarbondioxide.Therefore,themodelwasextendedtoasurfaceof20kmby30kmandtoadepthof6000m.Dataofabout9000boreholes,15reflectionseismiclines,aswellashigh-resolutionDEM´swereimported.Inafirststepageological3D-surfaces-modelisconstructed,whichcontainsabout20geologicalhorizonsandallimportantfaultstructures.Thissurfaces-modeloffersthebasisforavolume-model,whichoffersthepossibilitytoassignvariousspecificparameters(e.g.geophysical,hydraulical,geochemical)toadistinctbody.Suchageometricallyconsistentandparameterisedvolumemodelservesasanidealbasisfornumericalmodellingapproachessuchasgroundwaterflowsimulation.

Toaddressthegrowingimportanceofurbaninfluencestosubsurfaceprocesses,modelscontaininghighresolution(1-5mgrids)surfacesareneeded.Therefore,basedonthepresentedgeological3DmodeloftheBaselregionweplanamodel,whichfocusesonnearsurfaceobjectstypicalforhighlyurbanizedareassuchastunnels,watersupplychannels,subways,sewagesystem,cellars,parkinggarages,sitesusingshallowthermalenergyandwastedisposalsites.

REFERENCESZechnerE., Kind F., FähD.&Huggenberger P. 2001:A 3DGeologicModel of the SoutheasternRhinegraben compiledon

existinggeologicdataandgeophysicalreferencemodelling,2ndEUCOR-URGENTAnnualWorkshop2001,Abstractvolume.

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Use of digital terrain models and GIS for neotectonic studies: Analysing fluvial terrace morphology in northern Switzerland

FraefelMarielle1,KockStéphane2,SchnellmannMichael3

1 ETH Zürich, Institute of Terrestrial Ecosystems, Universitätsstrasse 16, CH-8092 Zürich (marielle.fraefel@env.ethz.ch)2 SC+H AG Chur, Ringstrasse 203, CH-7000 Chur3 Nagra, Hardstrasse 73, 5430 Wettingen

The tectonicevolutionofNorthernSwitzerland is intensively studiedbyNagra (NationalCooperative for theDisposalofRadioactiveWaste)inthesearchforapotentialdisposalsitefornuclearwaste.Tectonicstabilityisakeycriterionforthelocationofanuclear-wasterepositorytoachievesafeandlong-termcontainment.RecenttectonicdeformationratesandassociatedseismicactivityinnorthernSwitzerlandareverylow,asshownbygeodeticmeasurements(Nagra,2008)andtheseismotectonicrecord (Deichmannetal.,2000). Inordertobetterdescribetherecentdeformationfield,westudyyoungfluvialsediments (Niederterrasse) inthe lowerAareandRhinevalleysthatweredepositedbetweenca.32and11kaago(Bitterlietal.,2000;Kocketal.,2009).Thesealluvialgravelterracesrecordthepositionoftheriverbedbeforeoneofseveralincisionepisodes.Duetotheirrelativelysmoothdepositionalsurfaces,theterracesrepresentmarkerhorizonsfordetectingtectonicmovementsduringthelast10-30ka.Withouttectonicdisturbance,theirsurfacesareexpectedtoshowasmoothshapeandgentledownstreamdip.Irregularitiestothistrendcanbeasignforneotectonicactivity.

ThemorphologyoftheNiederterrassegravelsurfacesisanalysedinaGIS,usingthehigh-resolutiondigitalterrainmodelDTM-AV(Swisstopo,2007).Theindividualterracesaremappedusingelevationdifferences,slope,differenthillshadeillumi-nationsandtopographicrelief.Theprojectedtracesoftheterracesurfacesarethenplottedinalongitudinalvalleyprofile,allowingforthedetectionofalong-streamsteepnessvariations.The3Dorientationoftheterracesisapproximatedusinganautomatedplanartrendfunction.

Theresultsofthisstudyhelpvisualisingthepresent-daypositionandorientationofthepreservedterracesurfacesandcanbeanalysedforeffectsoftectonicdeformation.

TheterracedistributionindicatesaregionalnorthwardtiltinthelowerAarevalleyaftertheformationoftheNiederterrassegravelterraces,whichisinagreementwithgeodeticmeasurementsandthusseemstobeongoingtoday.NorthoftheJuramountains,intheRhinevalleybetweenKoblenzandBasel,theterraceoccurrenceanddipdirectionsgivenoindicationofaconsistentdeformationpattern.Thisisprobablyduetothecombinationofarelativelycomplexaccumulationanderosionhistoryandlowdeformationrates.Sofar,noclearevidenceoflocaliseddeformationaroundmajorfaultscouldbefound.

Thedigitalterrainmodelanalysisprovesahelpfultooltosystematicallyandreproduciblydescribeandinterpretthemor-phologyoffluvialterracesystemsoverlargeareas.Itallowsforthesimultaneousinvestigationofthe3Dshapeofalargenumberofriverterraces,thefastandreliableidentificationofmorphologicalpatterns,andabetterdifferentiationofsi-gnalscausedbygeologicalprocessesfromanthropogenicterrainmodifications.Whilekeepinginmindotherpossibleinflu-encesonriverterraceshapelikesedimentaryprocessesordataprocessingartifacts,thepresentedapproachfacilitatesafastandextensiveinvestigationforthegeomorphologicalexpressionsofneotectonicactivity.

REFERENCESBitterli,T.,Graf,H.R.,Matousek,F.,&Wanner,M.2000:GeologischerAtlasderSchweiz:Zurzach(Blatt1050),Erläuterungen.

Bundesamtf.Wasseru.Geologie,Bern,Switzerland.Deichmann,N.,Dolfin,D.B.,&Kastrup,U.2000:SeismizitätderNord-undZentralschweiz.NagraTechnischerBericht,00-

05.Kock,S.,Kramers,J.D.,Preusser,F.,&Wetzel,A.2009:DatingofLatePleistoceneterracedepositsoftheRiverRhineusing

uraniumseriesandluminescencemethods:potentialandlimitations.QuaternaryGeochronology,4:363-373.Nagra, 2008:Vorschlaggeologischer Standortgebiete für ein SMA-und einHAA-Lager:GeologischeGrundlagen.Nagra

TechnischerBerichtNTB08-04.Swisstopo2007:DTM-AV. geodata-news, 14,http://www.swisstopo.admin.ch/internet/swisstopo/de/home/products/height/

dom_dtm-av.parsysrelated1.19059.downloadList.63245.DownloadFile.tmp/gn142007defr.pdf(accessed07April2008).

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Insights from two high-resolution bathymetric surveys in Swiss lakes

MichaelHilbe1,FlavioS.Anselmetti1,RaymondEilertsen2&LouiseHansen3

1Eawag, Swiss Federal Institute of Aquatic Science & Technology, Überlandstrasse 133, CH-8600 Dübendorf (michael.hilbe@eawag.ch)2Geological Survey of Norway (NGU), N-9296 Tromsø3Geological Survey of Norway (NGU), N-7491 Trondheim

High-resolutiondigitalterrainmodels(DTMs),generatedbyairbornelaserscanningorothertechniques,havebeenwelles-tablishedinSwitzerlandforafewyears.Providingatypicalhorizontalresolutionofafewmetersorless,theyareusedforavarietyoftaskssuchasgeomorphologicalmappingorthemonitoringofearthsurfaceprocessesrelatedtonaturalhazards.Bathymetricdata(DTMs)fortheSwisslakes,however,sofardonotprovideacomparablelevelofdetailduetolimitationsofthe«traditional»surveytechniques, i.e.singlesoundingsorsingle-beamechosounders.Furthermorethesetechniquesarelabor-intensiveandthusnotsuitableformonitoringprogramsinvolvingfrequentlyrepeatedsurveys.State-of-the-artacou-stichydrographicsurveysystems(multibeamechosounders,swathbathymetrysystems)allowasignificantimprovementofthehorizontalresolutionofsubaquaticDTMstovaluescomparablewithhigh-resolutionterrestrialdata.SuchequipmentwasutilizedforthefirsttimeinSwitzerlandintheframeworkofapilotprojectstartedin2007.

NewdatacollectedduringtwofieldcampaignsonLakeLucerneandonLagoMaggioreusingaGeoAcousticsswathbathyme-trysystemandaccurateRTK-GPSpositioningrevealawealthofpreviouslyunknownfeaturesonthelakefloor.Additionally,backscatteranalysisallowsforaclassificationoftheacousticpropertiesofthelakefloor,e.g.adifferentiationbetweensoftsedimentsandhardrocksurfaces.

ThesubmergedvalleysystemofLakeLucerneischaracterizedbyacomplexglacialmorphologywithanumberofmoraineridges.Someofthemareprominentandhavebeenknownforalongtime,othersaremostlycoveredwithyoungersedimentsandareonlyexpressedbyalowreliefvisibleonthenewlycollecteddata.TheHolocenesedimentsonthelateralslopesareaffectedbymassmovements,thesignaturesofwhichcanbeaccuratelymappedandquantified.ThenortheasternpartofLagoMaggioreisdominatedbytwomajordeltasoftheMaggia,TicinoandVerzascarivers.Theslopesofthesedeltasarecoveredbyubiquitoussmall-scaleundulatingbedformsandincisedchannels,presumablyreflectingthedynamicsofriver-borneturbiditycurrents.

Astheseexamplesindicate,theuseofhigh-resolutionbathymetricdataisanappropriateandnecessaryapproachtomapotherwiseinvisibleunderwatermorphologies.Thedataarethebasisforsubsequentinvestigationsofthelakesedimentsandforotherapplicationsincoastalengineeringandconstruction,naturalhazardanalysisandnaturalresourcesprospecting.Periodicrepetitionsofthesurveyswillallowmonitoringandquantifyingalterationsofthelakefloorsrelatedtonaturalprocessesaswellastohumanimpact.

8.17

SyGEMe, Integrated Municipal Facilities Management of Water Ressources:

Tool presentation, choice of technology, man-machine interface, business opportunities and prospects

F.Kuchler1,G.Cherix1,R.Sauvain1,S.Storelli1,D.Lindemann2,E.Andrey3

1 Centre de Recherches Energétiques et Municipales (CREM), Av. du Grand-St-Bernard 4, CP 256, CH-1920 Martigny2 Depth SA, Chemin d’Arche 40 B, CH-1870 Monthey,3 Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire de Systèmes d’Information Géographique (LASIG), EPFL ENAC LASIG, Bâtiment GC, Station 18, CH-1015 Lausanne

Nowadays,watermanagement raisesquestions related to theglobal climate changes, the risingdemandof resources inemergingeconomiesandthedecisionsonenergypolicyabouttheexploitationofhydropowerandwaterprotection[1].InSwitzerland,thegeographicaldifferencescauseamarkeddifferenceinavailabilityofdrinkingwater,bothquantitativelyandqualitatively.So,publicmunicipalities,whichareafewmilesapart,canthereforebefacedtoanexcess,respectively,alackofwaterresource.

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es Meanwhile,thepublicauthoritieshavetheresponsibilitytomanagethevariousenergyflowsthatservethecities(water/

sewage,naturalgas,electricity,districtheating,TVnetwork)andthusensurethesafetyandqualityoftheservicestocusto-mers.Specificmanagementtoolsalreadyexistforeachspecificareabutthereisstillnointegratedtoolwhichallowsaglobalandcomprehensivevisionofthenetworksteeringandmanagement.Since2007,expertsfromtheResearchCenterinEnergyandMunicipalities(CREM)andtheEcolePolytechniqueFédéraledeLausanne (EPFL) incollaborationwiththecompaniesDepthSA,ESRISwitzerlandSA,SDIngénierieandSIGGenèvehaveworkedonthedevelopmentofamanagementtoolforintegratedmunicipalurbantechnicalnetworks,appliedinitiallytothewatercycle(SyGEMe).Themainobjectiveofthisprojectwastodevelopanewserviceforcommunitiesandnetworkoperators,whichincludesamonitoringsystem(withreal-timeflowsmeasurements)andanexpertsystemofknowledgemanagement,bothonageogra-phicinformationsystem(inputinterfaceofthetool).

Foroperators,thistoolavailablethroughawebplatformmustallow:

• thereal-timeanalysisoftheirnetworkoperation• thereceptionofalarmswhichcandetectnon-standardsituations• thesustainabilityoftheirpracticalknowledgeinnetworkmanagementwithanaccesstoastructuredinformationsy-

stemwhichfacilitatesregistrationandaccesstodataandoperationalexperiences.

TheSyGEMetoolhasentereditsfinalphase.Thesystemoffersmanyfeaturesthatwillbedevelopedinthisarticle.Butitispossibletomentionespeciallythedocumentationandgeoreferencingofobjectsandeventsonthenetwork,iemeasuringdevices,tasksandreportscreatedbyorfornetworkoperators,anaccesstoreal-timetelemetryetc.ThisarticleaimstopresentindetailstheSyGEMetool,todocumentthechoiceoftechnology,toidentifybusinessopportu-nitiesandtoimaginetheprospectsoftheSyGEMeproject.

Figure1-SyGEMe,onlineviewofthetool.

REFERENCES:OFEN,Officefédéraldel’énergie,Suisse:«Pland’actionpourlesénergiesrenouvelables»,Fiched’information6,2008Bruno Schädler, DivisionHydrologie, OFEV,Office fédéral de l’environnement, Suisse : « Dossier au fil de l’eau »,

Environnement–Avril2006Conventionalpine,Italie:«L’eaudanslesAlpes»,Communiquédepresse:SécheresseouCrue?2èmeRapportsurl’étatdes

Alpes,2009Conventionalpine,Italie:«L‘eauetlagestiondesressourceseneau:Rapportsurl’étatdesAlpes»,Signauxalpins–Édition

spéciale2–2009

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Towards a Swiss Geological Information System

AndreasKühni,NilsOesterling

Bundesamt für Landestopografie swisstopo, Landesgeologie, Seftigenstrasse 264, CH-3084 Wabern, andreas.kuehni@swisstopo.ch, nils.oesterling@swisstopo.ch

ThemaintasksoftheSwissGeologicalSurvey(SGS,FederalOfficeofTopographyswisstopo)aretoproducegeological,geo-physicalandgeotechnicaldataandinformationandtofacilitatetheaccesstorelevantdataforourmaincustomers.AsthegeologicalsurveyingactivitiesinSwitzerland–incontrasttomostEuropeancountries–isorganizedinafederalisticandhighlydecentralizedmanner,particularlythesecondgoalcanonlybeaccomplishedbyahighamountofcoordination.

InresponsetothefastgrowingdemandfordigitalgeologicaldataandinformationtheSGSstartedsomeyearsagotoputamajoreffortintheproductionofharmonizeddigitaldatasetssuchasgeological,geophysicalandgeotechnicalmapsaswellasdrillholedataandgeologicalreports.Ametadatabaseandaninteractiveviewerforallthegeologicaldataavailableatswisstopowerecreatedandmadeavailableontheswisstopohomepageinordertofacilitatetheaccessibilitytogeologicaldatatoourcustomers.Withtheavailabilityofthefirstgeologicalvectordatasetscoveringlargeareasatplanningscale1:25’000(e.g.cantonsVD,NE,JU),thedemandforthiskindofdataincreasedastheusebecameevidenttoalargerangeofprofessionalswhoneedgeologicalinformationininterdisciplinarydecisionmakingprocesses,suchasenvironmentalandurbanplanning,civilengineering,riskassessmentetc.However,onlyasmallfractionofthedataneededbyourmaincustomerscanbedownloadedfromtheSGShomepage.Theotherrequiredgeologicalandgeo-thematicdatahastobesearchedforandprocuredatdifferentcantonal,federal,scientificorprivateorganizations.

In order to further facilitate the access to all of the relevant data and information the SGS plans to build up a SwissGeologicalInformationSysteminclosecollaborationwiththemainplayersintheSwissgeologicalcommunitysuchasothercantonalandnationalgovernmentalbodies,thescnat(includingitsearth-sciencecommissions)andtheSwissAssociationofGeologists(representingtheprivateeconomysector).

Figure1:SchematicoverviewofthestructureoftheSwissGeologicalInformationSystem.Theavailablegeologicaldataandinformation

areatthecoreofthesystem.Accesstothedataisprovidedviaaweb-portalordirectlyviaweb-services.Theentiresystemisdividedinto

threesectorscoveringissuesrelatedtogeo-data,geo-knowledgeandthegeo-community.Eachsectorcontainsdifferentcomponents,e.g.a

dataviewerforvisualizinggeologicaldataoradiscussion-forumforthecommunicationbetweenprofessionalsandlaymen.Thetarget

groupsareprofessionalgeologists,semi-professionalsingeology(e.g.teachers)aswellaslaymenfromabroadpublic.

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thenationalinternetportal:

1. GEO-DATA:Improveaccessibilitytoalldataandinformationrelatedtogeology2. GEO-COMMUNITY:Giveanoverviewofthetasks,responsibilities,productsandservicesoftheinstitutionsinthe

fieldofearthsciencesinSwitzerland3. GEO-KNOWLEDGE:Increaseawarenessoftheimportanceofgeologicaldataatpoliticalandpubliclevels.

InordertoreachthesegoalstheSGSinworkinginthree main pillars:technicalinfrastructure,dataproduction/acquisition,coordination/legalaspects.

Technical Infrastructure:ThetechnicalimplementationisbasedontheguidelinesoftheNationalSpatialDataInfrastructureofCOGIS(Coordination,Geo-InformationandServices,swisstopo),aplatformaimingtolinkallspatialdatarelevanttotheSwiss(public)economyatanationallevel.Thusthetechnicalinfrastructureistoalargeextentalreadyprovided.Inordertoallowthehomogeneousintegrationandtheinteroperabilityofgeologicaldatafromdifferentsourcesageneralgeologicaldatamodelisbeingdeveloped(Oesterling2006;Strasky2009)

Data Production and Acquisition:Duringthelastdecadetheproductionofdigitalgeologicaldatahasbeenincreasinglypushed.All of the geologicalmaps are available in pixel format andmost in vector format. Thenewly initiated projectGeoCover (Baland2009)aims tomakea seamlessgeologicalvectormap (scale1:25’000–1:50’000)availablewithin threeyears.TheinternalproductionoftheGeologicalAtlas1:25’000iscurrentlyofbeingtransferredtoaGISproductioncyclebasedonthesoftware ‘ToolMap’ (Schreiber2009),whichwasdevelopedincollaborationwithcrealp (Researchcenteronalpineenvironment).ThecollaborationwiththeSwissGeotechnicalandtheSwissGeophysicalCommissionshavebeenin-tensifiedandtherespectiveproductsareintegratedintotheGeologicalDataViewerofswisstopo.

Coordination and Legal Aspects:AlthoughtheSGShasastronglegalbase(SchweizerischeEidgenossenschaft2008a,b)foritsdutiesandespeciallyforitscoordinationandturntablefunctionsince2008,mostoftheexternalproducersofgeologicaldataandinformationarenotforcedbylawtointegratetheirdatainapubliclyaccessibleplatformandtomakegeologicaldataavailabletothepublic.ThereforeandbecauseofverylimitedrecoursesthebuildingupofaGeologicalInformationSystembytheSGSdependstoalargedegreeonthecapacityofitspotentialpartnerstounderstandthatsuchaninformationsystemwillfacilitatelifeforallthemembersoftheSwissgeologicalcommunityandstrengthenthepositionofgeologyintheSwisssocietyingeneral.

REFERENCESBaland,P.2009:Convertinggeologicalmapstovectordatasets–CompletingtheNationalGeologicalInformation;SGM09,

poster,thisabstractvolumeOesterling,N.,Jemelin,L.,Kühni,A.2006:TheGeologicalInformationSystemofSwitzerland–DataModelandDataViewer,

33rdInternationalGeologicalCongress,Oslo,Proceedings,Volume1,235-237.Oesterling,N.,Kühni,A.andKündig,R.2008:TheGeologicalInformationSystemSwitzerland,6thEUREGEOProceedings,

Volume1,235-237.Schreiber,L.,Ornstein,P.,Sartori,M.,Kühni,A.2009:TOOLMAP–‘Sion’method:developmentofanewGISframeworkfor

digitalgeologicalmapping,6thEUREGEOProceedings,Volume1,89-90.SchweizerischeEidgenossenschaft (2008a),BundesgesetzüberGeoinformation (Geoinformationsgesetz,GeolG), Stand: 1.

Juli2008,BernSchweizerischeEidgenossenschaft(2008b),VerordnungüberdieLandesgeologie(Landesgeologieverordnung,LGeolV),Stand:

1.Juli2008,BernStrasky,S.2009:TowardsaSwissgeologicaldatamodel;SGM09,oralpresentation,thisabstractvolume

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Rock glacier monitoring with low-cost GPS receivers

LimpachPhilippe&DavidGrimm

Institute of Geodesy and Photogrammetry, ETH Zurich, Schafmattstrasse 34, CH-8093 Zurich (limpach@geod.baug.ethz.ch, grimm@geod.baug.ethz.ch)

Toinvestigatethepotentialoflow-costGPSreceiversfortheprecisemonitoringofslopeinstabilitiesinmountainareas,asmallGPStest-networkwasinstalledontheDirrurockglaciernearRanda,Mattertal,SwissAlps.ThesitewasselectedbytheAlpineCryosphereandGeomorphologyresearchgroupoftheUniversityofFribourgandtheSwissFederalOfficefortheEnvironment,basedonvelocitiesdetectedbySARinterferometryandperiodicGPSsurveys(Delaloyeetal.2007).

Thetest-networkwasinstalledinJune2009andconsistsofthreepermanentGPSstations(Figure1),equippedwithlow-costmono-frequencyGPSreceiversfromtheSwissmanufacturerμblox.Powerissuppliedbysolarpanels.TovalidatetheresultsfromtheGPSnetwork,parallelobservationswithanautomatedtachymetersystemwerecarriedout.Aminiprismwasin-stallednexttoeachGPSantennaonthesameboulder(Figure2).Theprismsweremeasuredbythetachymeterevery30min-utesduringtwoweeks.

TheGPSdataprocessingisbaseddifferentialcarrierphasetechniquesusingtheBerneseGPSsoftware.Dailystationcoordi-nates,aswellaskinematiccoordinateswithasamplingintervalof5sarecomputed.Thelow-costGPSsystemallowedtoreliablyobservevelocitiesintheorderof2cm/day.Stationcoordinateswereobtainedwithaccuracies(standarddeviations)of0.5cmforthedailysolutionsand1.5cmforthekinematicsolutions.Averygoodvelocityagreementofbetterthan0.1cm/daywasobtainedwithrespecttothetachymetersolutions.

Byprovidingcontinuousobservationsofsurfacemotion,independentofweatherconditions,permanentmonitoringbasedonlow-costGPSreceiverscanhelptostrengthentheunderstandingofprocesseslinkedtopermafrost-relatedslopeinsta-bilities.Inaddition,itisapowerfultooltoenhanceexistingmonitoringandearly-warningsystems,inordertoimprovethepreventionandmitigationofimpactsofnaturalhazardsoninfrastructureandhumanlife,andtosupportlocaldecision-makingprocesses.

Figure1.GPSstationinstalledontherockglacier,including(fromrighttoleft)GPSantenna,solarpanelandinstrumentboxcontaining

GPSreceiverandbattery.

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Figure2.GPSantennaandminiprisminstalledonthesameboulder(leftpicture)andminiprismindetail(rightpicture).

REFERENCESDelaloye,R., Strozzi,T., Lambiel,C.,Perruchoud,E.,Raetzo,H.2007: Landslide-likedevelopmentof rockglaciersdetected

withERS-1/2SARinterferometry.ProceedingsofFRINGE2007Workshop,Frascati,Italy,26-30November2007.

8.20

A GIS tool to create fluvial flooding maps. Interaction of 1D hydrodynamic model and GIS

MarzocchiRoberto1,FedericiBianca2,SguersoDomenico2

1 IST – SUPSI Istituto scienze della Terra, CP 72, CH-6952 Canobbio (roberto.marzocchi@supsi.ch)2DICAT, Università degli Studi di Genova, Via Montallegro 1, 16145, Genova (Italy)(bianca.federici@unige.it)

Eachyearfloodinghappensworldwideposingatriskthelifeandthepropertyofmillionpeople.Anincrementoftheexpo-suretoriskiscausedbyclimatechangesandpopulationgrowththatleadstothedevelopmentofinfrastructures,buildingsandbusinessintheareassurroundingrivers.However,floodingisanaturalphenomenonandisnecessaryforthesurvivalandhealthoftheecosystem.

Theidentificationoffloodproneareasisofconsiderableimportanceeitherforemergencymanagementandforplanningactivity,suchasschedulingofworksforthereductionofhydraulicriskortownplanningfinalizedtotheoptimallanduse.For this reason in recent years several flooding hazardmodels and risk assessment procedures were developed. Also aGeographicInformationSystem(GIS)maybeatoolthatcanassistfloodplainmanagersasdecisionsupportsystem.ThepresentworkproposesanautomaticprocedureimplementedinGISenvironmenttocreateperifluvialfloodingmaps.Thepotentiallyfluvialinundatedareasareobtainedknowing(i)theconformationofthefloodplainsurroundingtheriverbyanhighresolutionDigitalTerrainModel(DTM)and(ii)awatersurfaceprofilealongtheriveraxiscalculatedforgivendischargethroughagenericone-dimensionalhydraulicmodel(HEC-RAS,Basement,MIKE11,etc).Theinterestfortheinter-actionbetweenaGISandcommonhydrodynamicmodelsisshownbymanyworksinliteratureandbytheimplementationofseveralsoftwaretothispurpose(HEC-GeoRAS®,Mike11GISandSurfacewaterModelingSystem).Theimplementedprocedurehasinnovatingcharacteristics:infact,evenifitremainssubstantiallyone-dimensional,ittakesinto account the two-dimensionality of floodplain and inundationphenomena, adducinghypotheses that let to correctmanyerrorstypicalofone-dimensionalusuallyemployedprocedures.Hence,withrespecttotheuseofanone-dimensionalmodelwithouttheGISsupport,thisprocedureallowstoobtainmorerealisticperifluvialfloodingmap(fig.1).Moreover,withrespecttoatwo-dimensionalmodel,itneedsalowercomputationaleffort,thatallowstoapplyittoriverreachesverylong(oftheorderof100km).

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sTheproceduremaybesummarizedinfourphasesthatareautomaticallyimplemented(moredetailinMarzocchietal.2009).Inthefirstphase,thevalueofwaterlevelinthenearestpointoffluvialaxisisassignedtoeachcellofDTM,throughthecreationofThiessenpolygons;hence,afirstfloodingmapisobtainedmakingacomparisonbetweenelevationandwaterlevelineachcell.Inthesecondphase,theprocedureremovesalltheareaspreviouslydefinedathazard,butnotconnectedwiththeriveraxis.Inthethirdphase,theproceduretakesintoaccountleveesorotherobstructionstothewaterflow,underthehypothesisthatwaterdiffusesfromrivertothesurroundingareasonlyindirectionperpendiculartotheriveraxis.Inthefourthphasetheprevioushypothesis isremovedand,onlyfortheareasdriedinthethirdphase,severaltwo-dimen-sionalwaterpathsareanalysed,obtainingthefinalfloodingmap.

Afirstvalidationoftheprocedurewasperformed(Federicietal.,2007)onareachoftheTanaroRiver(about120Km,Italy):thehistoricalinundatedareaandthepotentiallyinundatedareacausedbythealluvialeventin1994thatinterestedtheriverthroughAlessandriacitywerecomparedwithsatisfactoryresults.Recently,thetoolhasbeenappliedalsotoalittlestream(RoggiaScairolo)intheTicinoCanton,forthefloodinghazardvaluation(Pozzonietal.,2009)obtainingreliablere-sults.

TheprocedurewasimplementedintheopensourceGeographicResourcesAnalysisSupportSystemSoftware(GRASS,2008)combiningtheuseoftheshellscriptandfortranlanguages.Anewmodule(r.inund.fluv)withauserfriendlygraphicalin-terfacewascreatedandnowitisdistributedunderthetermsoftheGNUGeneralPublicLicense,freedownloadingfromthewebsitehttp://grass.osgeo.org/wiki/GRASS_AddOns.

Figure1.WorkingprincipleoftheimplementedGIStool.

REFERENCESFedericiB.,SguersoD.,2007.Proceduraautomaticaperlacreazionedimappedipotenzialeinondazionefluviale.Bollettino

SIFET,ISSN:1721-971X,n.4,pp.25-42.Marzocchi,R.,Federici,B.&SguersoD.2009Proceduraautomaticaper lacreazionedimappedipotenziale inondazione

fluvialeinGRASS:ilmodulor.inund.fluv,AttidelIXMeetingdegliUtentiItalianidiGRASS-GFOSS,21-22febbraio2008,pp.161-178

GRASSDevelopmentTeam2008.GeographicResourcesAnalysisSupportSystem(GRASS)Software.OpenSourceGeospatialFoundationProject.http://grass.osgeo.org

Pozzoni,M.,Marzocchi,R.&Graf,A. 2009.RoggiaScairolo - Zonazionedellapericolositàperalluvionamento,TechnicalreportIST

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A GIS embedded model for dam break

MarzocchiRoberto&CannataMassimiliano

1IST – SUPSI Istituto scienze della Terra, CP 72, CH-6952 Canobbio (roberto.marzocchi@supsi.ch)

IntheXXIcenturyaround200notabledamandreservoirfailureshappenedworldwidecausingmassivefatalitiesandeco-nomiccosts.Increasingenergydemandandotherbenefitshavecausedtheconstructionofmanydaminmountainousregi-ons;atthesametimetheintensivewatershedurbanizationhasleadtoasocietyexposedtoriskslikeneverbefore.Forthisreason,nowadaysgovernmentsarelookingintodisastermitigationstrategieswithhigherattention.Withintheprocessofstrategies,designthespatialinformationplaysaninvaluablerole.Infactisimpossibletotakeeffectiveandcomprehensivedecisionswithoutunderstandingtheextentofpotentialhazardsandwithoutlocalizingexistingconditionsofvulnerabilitythatcouldposeapotentialthreattoharmpeople,properties,essentialservicesandeconomyofregions.Therefore,inordertoprotectthesocietyfromagiventypeofhazardisofprimaryimportancebeingabletoassessthespatialdistributionofthethreateningphenomenaandtheirintensities.

Inordertoperformriskanalysis(fig.1),GISrepresentaneedfulinstrument.Usuallyhazardareasareevaluatedbyusingstandalonehydrodynamicmodels,whileGISareusedtomanageinputsandtoperformtheriskanalysisusingoutputs.Thisapproachistimeexpensive,errorprone,duetoexport/importrequirements,andnotuserfriendly,butnecessarybecauseofthelackofembeddedGIShazardmodels.

Tothispurpose,theInstituteofEarthScienceisdevelopingaseriesofGISembeddedhazardmodelswithintheRiskBoxproject(Cannata&Molinari,2008).Theaimofthisprojectistoprovideauniquesystemofferingallthecapabilitiesrequiredbyriskassessmentanalyses.ThechosenGISsystemistheGeographicResourcesAnalysisSupportSystemSoftware(GRASS,2008).Itsselectionwasbasedontheconsiderationthatthissoftwareprovideshighquality,flexibilityandinteroperability,and,leastbutnotlast,thatitisOpenSource.

Withthiswork,anewnumericalmodelforthesolutionofthetwo-dimensionaldambreakproblemhasbeenimplementedintheGRASSGISasaembeddedmodule.Themodelsolvestheconservativeformofthe2DShallowWaterEquations(SWE)usingaFiniteVolumeMethod(FVM);theinter-cellfluxiscomputedbyone-sideupwindconservativescheme(Yingetal.,2004)extendedtoatwo-dimensionalproblemonasquaredgrid.

Thecommandcangeneraterastertimeseriesofwaterdepthandflowvelocitywithtimeresolutiondefinedbytheuser,andavarietyofoutputrastermapsusefultoobtainthemaximumphenomenonintensity(BUWAL1998).TheproblemformulationandthenewGRASSmodulearedetailedpresentedinreferences(Marzocchi&Cannata,2009).Themodelhasbeentestedwithtwostandardsyntheticproblemsreferencedinliteratureandverifiedinarealdamcasewhereofficialfloodingmapswereavailable(fig.2).Acomparisonwithotherexistingdambreakmodelswillbeconduct.

Figure1.Riskassessmentstrategyincaseofdambreak

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Figure2.Testcasesusedformodelvalidation

REFERENCESBUWAL1998MethodenzurAnalyseundBewertungvonNaturgefahren.Umwelt-MaterialienNr.85,Bern,p.229CannataM.&Molinari,M.2008,NaturalHazardsandRiskAssessment:theFOSS4Gcapabilities.ProceedingsoftheFreeand

OpenSourceSoftwareforGeospatial(FOSS4G2008)conference.CapeTown,SouthAfrica.GRASSDevelopmentTeam2008.GeographicResourcesAnalysisSupportSystem(GRASS)Software.OpenSourceGeospatial

FoundationProject.http://grass.osgeo.orgMarzocchi,R.&Cannata,M.2009.Two-dimensionaldambreakfloodingsimulation:aGISembeddedapproach.InpressYing,X.,Khan,A.&Wang,S.S.Y.2004.UpwindconservativeschemefortheSaintVenantEquations

8.22

Naturereignisse entlang der Bahnlinien: eine systematische Aufnahme

MeierAndreas&WilliChristina

SBB Infrastruktur, Umwelt, Naturrisiken, Mittelstrasse 43, 3000 Bern 65

Die Bahnlinien sind aufgrund der topografischen Gegebenheiten in der Schweiz häufig klimatischen und gravitativenNaturprozessenausgesetzt.Sturzprozesse,Hochwasser,Hangrutsche,Murgänge,Lawinen,SturmwindeundStarkniederschlägesindNaturgefahren,welchetypischerweisedieSBB-Liniengefährden.

DiesystematischeErfassungderNaturereignisseistausfachlicherundbetrieblicherSichtvongrosserBedeutung.DieSBBstrebtmitderErstellungundPflegeeinesnetzweitenEreigniskatastersNaturgefahrenan,eindifferenziertesBildüberdieAuswirkungenvonNaturereignissenaufInfrastrukturundBahnbetriebzugewinnen.

EreigniserfassungMit dem «Geographischen Informationssystem GIS NR» der SBB werden gravitative Naturgefahren sowie Einflüsse derWitterung auf die Infrastruktur in einem zweistufigen Prozess erfasst, dokumentiert und visualisiert. Die wichtigstenInformationenzueinemEreignisumfassen:

• Ereignisdatumund–ort• Ereignisart,-beschreibungund-bewertung• Prozesskenngrössen,Prozessart,Wirkungspunkt,Auslöser,Ursachen,Auswirkungen• Personen-(Verletzte,Tote),Sach-(CHF)undBetriebsschäden(Verspätungsminuten,Zugsausfälle,Störungen)• SicherheitsbezogenerEreignistyp• AngabenzuSofort-undFolgemassnahmen

Die Daten werden laufend aktualisiert und ergänzt. Sie bilden die Grundlage für die Ereignisanalyse und denJahresrückblick.

Datenauswertung und Erstellung von KenngrössenGISNRermöglichtdieErstellungvondefiniertenAbfragenausdemEreigniskatasterunddieraumbezogeneBetrachtungvonEreignisabfolgen.AufderBasisweitererSBB-internerDatendientdieAnalysederNaturereignissederErstellungvon

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BahnbetriebverfolgtwerdenundentsprechendeMassnahmengetroffenwerden.

FolgendeFaktenwerdenabgeleitetundjährlichverfolgt:

• RäumlicheVerteilungderEreignisse(Fig.1)• EntwicklungderEreignisse• AnzahlUnfälleundVerspätungsminuten• SummederversichertenSchäden• TypisierungvonSchadensbildern• EinschätzungderRisikolage• ÜberblickderStellenmitMassnahmenbedarf

Die Resultate der Ereignisanalysen werden im jährlichen internen Standbericht Naturrisiken und auf thematischenKartendarstellungenpräsentiert.

LangfristigwerdenaufBasisderüberdie JahregesammeltenDatenTrendanalysenzurEntwicklungderNaturereignissemöglichsein.

Figur1.NaturereignisseaufdemSBB-Netzseit01.01.2008

AusblickDiePflegeundAnalysevonEreignisdatenwirdweiter systematisiertundausgebaut.DamitwirdderEreigniskataster zueinemintegralenBestandteildesNaturrisikomanagementsderSBB.

Um die Schadensentwicklung und die Wirkung von Schutzausbauten zukünftig besser beurteilen zu können, werdenVergleichezunationalenundkantonalenEreignis-undSchadenskatasternimmerwichtiger.DieSBBunterstütztdieverschiedenenBestrebungeninderSchweizzurVerbesserungderDatenlagezuNaturereignissen.EineAusweitungdesNutzerkreisesdes «Geographischen InformationssystemsNaturrisiken»der SBB aufweitereBahnenkönnteausSichtderGefahrenpräventionundderBahnbetreibernotwendigeSynergienschaffen.

REFERENZENMeier,A.2008:Naturgefahren:HerausforderungfürdieSBB.GeomatikSchweiz2008/5,242-243.Meier,A.&Willi,C.2008:SystematicrecordingandanalysisofnaturalhazardsalongrailwaylinesusingGIS.SGM2008.

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Shallow Landslide Vulnerability Assessment

MolinariMoniaElisa1,CannataMassimiliano1,TroungXuanLuan2

1 Institute of Earth Sciences – SUPSI, Trevano, C.P 72, CH-6952 Canobbio2 Hanoi University of Mining and Geology – Dong Ngac, Tu Liem, Hanoi, Vietnam

ThePhilippines,Vietnam,Cambodia,Thailand,Laos,SumatraandIndonesiaareamongthecountriesidentifiedasclimatechange“hotspots”-countriesparticularlyvulnerabletosomeoftheworstmanifestationsofclimatechangeincludinglanslides.Inparticular,shallowlandslideshasahugedestructionpower.Becauseoftheirshighdensityandspeed,damagesareverysevereandsometimestragic:destroyinghouses,bridgesandinfrastructureandclaimingpeople'slives.Thethreatduetonaturalhazardscanbereduced,byintegratingthemintolandusemanagement,urbanplanning,andpopulationprotectionplans.Computersimulationisoneofafewpossibilitiestoobjectivelyassessthehazardduetoapro-cess,bysimulatingitslocalizationandexpansion.Twomodelsalreadyhasbeensuccessfullyappliedinmanycases:

• TRIGRS(Baumetal.2008)formodelingthetiminganddistributionofshallow,rainfall-inducedlandslides,and• DFWALK(Cannata&Molinari2008)formodelingtheexpansionareaandtheintensityofthephenomena.

Unfortunatelythistwosoftwarearenotlinkedtogetherthusdonotpermittheirusageforpredictingwhen,whereandwithwhatintensityaphenomenonisgoingtooccur.Thisresearchaimstocouplethetwoabovementionedmodels(TRIGRSandDFWALK)toderiveacompleteframeworkforshallowlandslidesmodeling.Thisachievementisveryimportantforplanningefficientcountermeasuresandintimedisasterresponses.Moreover,thisresearchaimsalsotoembedthistwomodelswithinaGISabletobeinterfacedwiththeInternetthroughaWebProcessingServiceimplementationinordertocreateaweb-basedapplicationforspatialdecisionsupportsystemsonshallowlandslide.Thissolutionenabletheusageofgeospatialdataformodelingandturnsitintoknowledgeableinformtion(maps)whicharemucheasiertounderstandandlessexpensiveforbetterdecisionmaking.

REFERENCESBaumR.L.,Godt J.W., SavageW.Z., 2008: TRIGRS –A fortranprogram for transient rainfall infiltration andgrid-based

regionalslope-stabilityanalysis,Version2.0.U.S.GeologicalSurveyOpen-FileReport08-1159.CannataM.,MolinariM.E,2008:NaturalHazardandRiskAssessment:theFOSS4G,Proceedingofthe2008FreeandOpen

SourceSoftwareforGeospatialConference,CapeTown,SouthAfrica.

8.24

3D modeling of geological heterogeneity: the direct sampling multiple-points simulation method

PhilippeRenard,GrégoireMariethoz,andJulienStraubhaar

Centre for Hydrogeology and Geothermics (CHYN), University of Neuchâtel, Emile-Argand 11, CH - 2009 Neuchâtel (philippe.renard@unine.ch, gregoire.mariethoz@unine.ch, julien.straubhaar@unine.ch)

Geologicalheterogeneityisakeyfactorcontrollinggroundwaterflowandtransportprocesses.Butbecauseofthelackofexhaustivegeologicaldata,itisoftennecessarytomodelitanditsimpactinordertoprovidenotonlyreliableforecastsbutalsoreliableerrorboundswiththegroundwaterflowmodelforecasts.Duringthelast50years,massiveprogresseshavebeenmadeinthisfieldbutmostlyinthecontextofrelativelysimpleheterogeneitymodels(binaryormulti-Gaussianmodels).However that therearea significantnumberofapplications inwhich theunderlyingassumptionsmadewhenapplying

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aspossiblegeological,hydrological,andgeophysicalobservations.Onetechniquethathasthesecharacteristicsisthemultiple-pointstatistics.Ithasbecomeaprevalentsubjectingeostatisticsoverthelast5-10years.Despitetheexistenceofcertainshortcomings,itisbynowthemostflexiblemethodtointegrateaconceptualmodelofheterogeneityinastochasticframework.Theconceptbehindthemethodistouseatrainingimagetorepresentthedesiredspatialstructureofthefield.Thetrainingimageisscannedandallpixelsconfigurationsofacertainsizearestoredinacatalogueofdataevents.Thisstructureisthenusedtocomputetheconditionalprobabilitiesateachsimulatednode.Becauseoflimitedmemoryusage,thestandardapproachcanonlydealwithcategoricalvariables,inaddi-tionthememoryloadcanbeprohibitiveforlarge3Dgrids.

Inthiswork,weshowthatthereisnoneedtostoreandcounttheconfigurationsfoundinthetrainingimage.Instead,itismoreconvenienttosamplerandomlythetrainingimageforagivendataevent.Thistechniqueisstatisticallyequivalenttopreviousimplementationsbut,becauseitrelaxestheneedtocomputeexplicitlytheconditionalprobabilities,itallowstoextend the application of the standard theory from categorical to continuous andmultivariate variables. Thismethod(Mariethozetal2009)canbeusedforthesimulationofgeologicalheterogeneity,accountingornotforindirectobservationssuchasgeophysics,butitcanalsobeusedtosimulateanyvariablethathasnonmulti-Gaussianfeatureswhichmayhaveanimportantimpactonhydrologicalprocesses.Computationally,itisfast,easytoparallelize,andparsimoniousinmemoryneeds.Acomparisonofitsapplicationforsolutetransportsimulationwiththeapplicationofstandardmulti-Gaussiantech-niques(Figure1)showsthatthisnewmethodisabletomodelcorrectlyhighlyconnectedpatternsthatareimpossibletomodelwiththeSequentialGaussianSimulationtechnique(Fig.1).

Figure1:Influenceontheconnectivitypatternsontransportbehavior.a)OnesimulationobtainedwithDirectsampling.b)Onesimula-

tiongeneratedusingSGS.c)Comparisonofhistogramsofsimulatedvalues.d)Comparisonofexperimentalomnidirectionalvariograms.

e)Comparisonofcontaminantbreakthroughcurvesontheoutflowboundary.f)andg)comparisonofthecontaminantdistributionat

t=250hours.

Moregenerally,themultivariateframeworkofferedbythismethodopensawiderangeofperspectivesfortheintegrationofdifferentdatatypes.Possibleapplicationsareverydiversesincecategoricalvariables(e.g.geology,soiltype,landcovercat-egory,vulnerabilityclass)andcontinuousvariables(e.g.porosity,concentration,rechargerate,rainfall)areoftenrelatedandwidelyusedinmanyfieldsofgeosciencesbutareveryseldommeasuredexhaustively.ThereforethesevariablesoftenrequiretobeinterpolatedorsimulatedandtheDSmethodcouldthenbeusedtosimulatefieldshavingaproperspatialstructure.

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simulations,WaterResourcesResearch,submitted.

8.25

Particle Swarm and Differential Evolution –Global Optimization for Geophysical Inversion

SaraswatPuneet

Indian School Of Mines University ,Dhanbad, Room 161 ,Topaz Hostel, Jharkhand-826004 (puneet.agpnasa@gmail.com)

Thesocialbehaviorobservedinaflock(swarm)ofbirdsandininsectssearchingfoodhasbeensimulatedtodevelopaglobaloptimizationstrategypopularlyknownastheParticleSwarmOptimization(PSO).ParticleSwarmOptimization(PSO)emu-latesthesocialbehaviorsinaflockofbirds(swarm)insolvinganoptimizationproblem.Itutilizesbothlocalandglobalpropertiesoftheswarmtoformulateanovelsearchstrategythatguidestheswarmtowardsthebestsolutionwithconstantupdatingofthecognitiveandsocialknowledgeoftheparticlesintheswarm.

DifferentialEvolution(DE)isanovelparalleldirectsearchmethodwhichutilizesNPparametervectorsxi,G,i=0,1,2,...,NP-1.(11)

asapopulationforeachgenerationG.NPdoesn'tchangeduringtheminimizationprocess.ItisaEvolutionaryalgorithmsuggestedbyStornandPrice(1996).Itisbasedonswarmoptimizationalongwithgeneticmutation,recombinationandse-lectioncriteriatooptimizeagivenproblem.Italsoutilizeslocalandglobalpropertiesofswarmalongwiththeirgeneticdevelopment.

WeusedPSOandDEforInvertingtheSeismicLogdata(bothrealandsynthetic)andcomparingthecomputedandobservedseismogram(generatedusingConvolutionforwardmodel),InvertedforAcousticImpedanceandresultsshowedanappro-priatematchwiththeobservedvalueoneandwasobtainedwithin1000iterationsandswarmof100inPSOand10timestheunknownparametersinDEForexample-oneoftheproblemwetookforsingletraceverticalseismiclogandinvertedforacousticimpedancevalueforeachlayerandagaincomputedseismogramusingcalculatedimpedancevaluesandplottedtheobservedseismogramwithcomputedonetheresultsareshowninfollowingfigures:

Figure1:SingleTracedatafitusingPSOwithVirticalseismiclogforAcousticImpedance

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Figure2:DatafitusingDifferentialEvolution,InvertedforAcousticImpedancefor135layeredearth,showsanexactfitofobservedand

computedvalueofseismogram.

Similarlyweworkedoverlargenumberofseismicdatabothrealfield(OilandNaturalGasCorporationOfIndiaseismicdata)andsyntheticdata(singletraceandmultipletraces)andInvertedforAcousticImpedanceandfoundgoodresultswithverylowerror.HencethetwonewtechniquesservedasexcellenttoolsforGeophysicalInversionInthisstudywereportedtheutilityofswarmintelligenceinsolvingmulti-parameteroptimizationproblemsingeophysics.Seismicdatahasbeeninvertedusingaclassicalparticleswarmoptimizerwith30-100individualsinaswarm.Forsyntheticaswellasfielddatasets,thesolutionsobtainedexplaintheobserveddatasatisfactorilybesidesexhibitingacceptablereso-lutionforthemodelparameters.

REFERENCESRaniaHassan2004:ParticleSwarmOptimization-methodsandapplication,MITesd16.888,ESO.77RainerStorn&KennethPrice1995:DiffrentialEvolution-a simpleandefficientadaptive scheme forglobaloptimization

overcontinuousspaces,TR-95-012

8.26

Fast Colorization, Analyses and Visualization of Airborne Laser Data

YannickStebler,PhilippSchaer,JanSkaloud

Swiss Federal Institute of Technology, Lausanne (Switzerland)

Airbornelaserscanning(ALS)hasbecomeverypopularformodelingtopographicobjectsbecauseofthehighresolutionandaccuracyaswellastheshortacquisitiontimerequiredforlargestudyarea.Thedigitalelevationmodel(DEM)ofthesurveyedareaisoftenrepresentedbymeanofpointcloudtriangulationconsideringahorizontalplane.Thisimpliesthatonlyonesinglealtitudevaluecanbesetforeachpoint(2.5-dimensional)issuedfromtheALSdata.Suchamodelingisnotsuitableforverysteepterrainandcliffs,whichmaybeofhighimportanceforunderstandinggeologicalfeaturesornaturalhazardcauses.Helicopter-basedALSsystemasthatdevelopedbyEPFL(Skaloudetal.,2006)canbemountedobliquelytoallowsteepandverticalcliffstobecapturedforanoptimalscanangle.Atthesametime,orientedimagesaretakentoproduceortho-rec-tifiedimagery.Inordertogetarealisticmodelofsuchterrain,rigorous3Dmodelsneedtobeproducedbasedontriangula-tionandimagedrapingontheresultingmesh.Thisprocedureispossiblebutratherinvolvedcomputationallyandintheabsence of standardized data structures the results are often not portable across software applications (Buckley et al.,2008).

Wepresentalightweight,fastandrobustalternativetothe3Dmodelingthatdirectlyexploresthehighdensitylaserdataandthehigh-resolutionimagery(collectedtogetherorseparately).TheproposedmethodassociatesaRGBvalueforeachlaserpulse.Itpresumesgoodqualityexterior-orientation(EO)forthecameradataanditsgoodcalibration.Thecamera’sEOiscalculatedbytheCAMEOsoftware(SkaloudandLegat,2006)foreachimageinthesamereferenceframeasthatoflaserdata.

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sAsonelaserpointcanbevisiblewithinseveralimages,avectorisreconstructedbetweenthelaserpointcoordinatesandthecamerapositiontochoosethemostoptimalimagefortheRGBextraction.Thischoiceismadeaccordingtotheanglebet-weenthisvectorandtheestimatedsurfacenormal.Thepixelcoordinatesandthustheassociatedradiometricvaluescorre-spondingtothelaserpointarecomputedbyapplyingtheclassicalcolinearityequationsandarefinallycorrectedforradiallensdistortions.Forinteroperabilitypurposes,theobtainedRGBvaluescanbestoredtogetherwiththelaserdatainstan-dardformatssuchasLAS1.2.

ThevisualizationengineisbasedonC++/OpenGLapproachandisoptimizedforsimultaneoushandlingoftensofmillionsofpointsoversteepterrainandcliffs.Asmearingfeaturecanbeappliedateachzoomlevel,sotheuserhaveanimpressionofseeingfull3Dmodelinsteadofdiscretevalues(Fig.1).

Finally,thedescribedsoftwareplatformallowsalsoanalysesoftheterrain.First,thelaserpointsareindexedintoakd-treedatastructureandthenaterrainnormalisestimated.Theestimationoftheterrainnormalisachievedbylocalcovarianceanalysis.Thisprocedureincludesanautomatedclassificationalgorithm(BaeandLichti,2004)forremovingthevegetation.Oncethecovarianceanalyzesiscompletedthelaserdatacanbecoloredforslope(Fig.2)andorientation(Fig.3).

Figure1:PointcloudcolorizationaccordingtoRGBvalues.

Figure2:Pointcloudcolorizationaccordingtoterrainslope.

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Figure3:Softwareinterfaceshowingtheterrainorientationdisplayingmode.

AcknowledgmentThisprojectwaspartiallyfinancedbyAlp-Sproject1.14AB.Thissupportisgreatlyappreciated.

REFERENCESBae,K.-H.,andLichti,D.,2004,EdgeandTreeDetectionfromThree-dimensionalUnorganisedPointCloudsfromTerrestrial

LaserScanners,12thAustralianRemoteSensingandPhotogrammetryConference:Fremantle,Australia.Buckley,S.J.,Wheeler,W,Braathen,A,Vallet,J,2008.ObliqueHelicopter-BasedLaserScanningforDigitalTerrainModelling

andVisualisationofGeologicalOutcrops. The InternationalArchives of the Photogrammetry,Remote Sensing andSpatialInformationSciences,Beijing,Vol.XXXVII,PartB5,Commission5.

Skaloud,J.,andLegat,K.,2006.CAMEO-CameraExteriorOrientationbyDirectGeoreferencing.:SwissFederalInstituteofTechnologyLausanne(EPFL).

SkaloudJ.,Vallet, J.,Keller,K.Veyssiere,G.,Koelbl,O.,2006.AnEyeforLandscape -RapidAerialMappingwithHandheldSensors.GPSWord,May2006.

8.27

Topography and surface processes in borderline ecotones

StrählS.C.1,KuhnN.J.2

1Geographisches Institut, Klingelbergstrasse 27, CH-4056 Basel (sarah.straehl@unibas.ch)2Geographisches Institut, Klingelbergstrasse 27, CH-4056 Basel

Climate,soilandhumanactivitystronglyaffectthevegetationpatternsinborderlineecotones.Vegetationborderlinesarecharacterizedbycertainabioticandbioticfactorsanddifferbetweentheecosystems.Borderlineecotonesrepresentareasoftransitionbetweenabioticandbioticfactorscontrollingtheborderlineecosystem.Borderlineecotonesthereforecontainagreatnumberofecologicnichesandwidespeciesdiversity.Successionprocessesleadtotheexistencevaryingvegetationpatterns.Thesesubsidingsuccessionprocessesareimportantforthevegetationdynamicandlastgenerallyoverseveral100years.Climateandenvironmentalchangeshaveanimportantinfluenceonvegetationdensityanddiversity.

Borderlineecotonesintwodifferentclimaticregions,coldandaridstudyarea,arecompared.ThealpinestudysiteisintheregionofGrindelwald(BerneseOberland),wherevegetationpatternsareinfluencedbytemperaturegradient:forest–dwarfshrubs–alpinegrassland.ThearidstudyareaissituatedinasidevalleynearSedeBoqer(Negevdesert,Israel),wherevege-tationpatternsareinfluencedbywatersupply.TheBraunBlanquetvegetationmappingmethodwasusedtodetermineve-getationtypeanddirectionofsuccession.Resultsshow,thatnotonlytemperatureandprecipitationinfluencesurfacepro-cesses inborderlineecotones. Inbothareasgeomorphdynamicprocessesplayan importantrole inthedevelopmentofvariousvegetationpatterns.Animportantquestionisthereactionofthesesystemsinthecoming100yearswiththeinflu-enceofGlobalclimateandenvironmentalchange.

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sREFERENCESBurga,C.A., Perret,R. (2001):Monitoringof easternand southernSwiss alpine timberlineecotenes. Tasks for vegetation

science35.InBurga,C.A.,Kratochwil,A..Biomonitoring:Generalandappliedaspectsonregionalandglobalscales.Holtmeier, F. DieHöhengrenze derGebirgswälder. Arbeiten aus dem Institut für Landschaftsökologie.Westfälische

Wilhelms-Universität. Band8,Münster.VerlagNaturundWissenschaftHarroHieronismusundDr. JürgenSchmidt.Postfach170209Solingen.2000.

Olsvig-Whittaker, Shachak,M.&Yair,A. (1983):Vegetationpatterns related to environmental factors in aNegevDesertwatershed.Accepted30May1983.

Yair,A.&Raz-Yassif,N.(2003):Hydrologicalprocessesinasmallaridcatchment:scaleeffectsofrainfallandslopelength.Received1July2003.Receivedinrevisedform1December2003.Accepted3December2003.

8.28

Towards a Swiss geological data model

StraskyStefan1,BalandPauline1,OesterlingNils1&KühniAndreas1

1Federal Office of Topography swisstopo, Swiss Geological Survey, Seftigenstrasse 264, CH-3084 Wabern (stefan.strasky@swisstopo.ch)

After~80yearsoftraditionalgeologicalmapproductionfortheGeologicalAtlasofSwitzerland1:25000(GA25),agrowingneedforvectordatasetsofthismapserieshasevolvedduringthelastdecade.ConsiderableeffortisthereforebeingspentbytheSwissGeologicalSurveytoconverttheexistingprintedGA25intohigh-qualityGeographicalInformationSystem(GIS)datasets.Tospeeduptheconversionfromrastertovectorgraphicsandtomeettherequirementsofthegeo-community,theSwissGeological Survey recently initiated theGeoCover project,which aims to provide geologicalGIS-data at a scale of1:25000throughoutSwitzerlandwithinthenextthreeyears.

However,awell-establisheddatamodeltodescribethestructureofthegeologicaldata,withspecificobjectandattributedefinitionsandtheirrelationships,isstillmissing.Anearlyattemptofaconceptualdatamodel,basedontheGA25mapofZurzach,waspresentedbyJemelin&Beer(1999).Baland-Renaud&Oesterling(2007)extendedthedatamodeltoallexistingGA25mapsbyusingthecatalogueoflinesandsymbolsfortheGA25,whichwaspublishedbytheFederalOfficeforWaterandGeology(2002).Nevertheless,themodeldevelopedbyBaland-Renaud&Oesterlingisabetaversion,andthusneedstobefurtherrefinedinordertocarefullystructuretheoriginalheterogeneityofthecurrentmapdata.TheaimofourprojectistoestablishastructuraldesignforthegeologicaldataoftheSwissGeologicalSurveyandtodescribeallrelevantobjects,attributesand relationships. Furthermore, thedatamodel should serveasa fundamentalbasis for the compilationofaseamless,nationwidevectordatasetofSwitzerland.Incollaborationwithanexternalgroupofexpertsweapproachthere-finementofthemodel.Herewepresentsomeexamplesofthenewestresultsaswellascurrentchallenges.

REFERENCESBaland-Renaud,P.&Oesterling,N.2007:Modèlededonnéesgéologiques.Partie:stockagedesdonnées,Version1.0,117pp.FederalOffice forWaterandGeology2002: LineandSymbolCatalogue for theGeologicalAtlasof Switzerland1:25000.

Version1.1,35pp.Jemelin,L.&Beer,C.1999:GeologischerAtlasderSchweiz1:25’000Erfassungskonzept,GIS-ApplikationundStrukturder

Datenbank,Bull.angew.Geol.,4/2,103–115.

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The Swiss Atlas of Physical Properties of Rocks (SAPHYR)

TripoliBarbara1,ZapponeAlba1,BurliniLuigi1,BurgJean-Pierre1,HollingerKlaus2&KisslingEduard1

1Departement of Earth Sciences, ETH Zürich, Sonnegstrasse 5, CH-8092 Zurich, Switzerland2Institute of Geophysics, University of Lausanne Amphipole - UNIL SORGE , CH-1015 Lausanne

Physicalpropertiesofrocksarekeyparametersforseveraldisciplinesspanningfromoilindustrytoengineeringtogeophy-sics,petrology,structuralgeologyandwaterresources.Theyarethereforeusefultoseveralscientificdisciplinesaswellastoindustryandsociety.

Since2006,amultiyearprojectrunsundertheumbrellaoftheSwissGeophysicalCommission(SGPK),withtheaimtodigi-tizeallexistingdataonphysicalpropertiesofrocksandtolinkthemusingageographicalframe(GIS),sothattheycanbereadyaccessibletoawidepublic.Moreover,wheredataarelackingorspare,campaignsofmeasurementsonrocksamplesarepromotedwithinthisorotherprojects.Theproject is focusedondatafromtheSwissAlpsbut, isnot limitedtothebordersofSwitzerland.

TheresultantmapswillbeintegratedintheAtlasofSwitzerland.Thefutureevolutionofthisprogramcouldbeanextensionto3-D,usingthestructureoftheexposedgeology,thedatafromboreholesandfromgeophysicalinvestigation.

8.30

Estimation of local tectonic movements using continuous GNSS network

VilligerArturo1,HellerOliver1,GeigerAlain1,KahleHans-Gert1&BrockmannElmar2

1Geodesy and Geodynamics Lab, Institute of Geodesy and Photogrammetry, ETH Zürich (arturo.villiger@geod.baug.ethz.ch)2Swisstopo

ThecantonValaisisaseismicactiveareawithinSwitzerland.However,comparedtootherregionslikeGreecetheexpectedtectonicmovementsareatleastonemagnitudesmaller.Thepredictedvelocitiesarefewmillimetresperyear.DuringtheprojectTECVAL,initializedbyHAZNETfunds,fivepermanentGPSstationshavebeenbuiltcoveringtheWildstrubelarea.Thestationshavebeenmountedonvariousbuildingssuchassewageplantswhicharewellconnectedtothegroundtored-ucelocaleffectssuchasslowlandslipsorothernon-tectonicprocesses.CombiningstationsfromTECVAL,IGS,RGN,andAGNESyieldstoabetterlocalvelocityfielddirectlyprocessedintotheITRF2005referenceframe.Forthispurposethesoftwarebernese5.0hasbeenusedtoprocessdailysolutionsofthemeasuredpoints.Asthemainresearchtaskisthelocaltectonic,alocallyadjustedrotationalvelocityfieldhasbeenestimatedandreduced.Foreverytimeseries,undertheassumptionofatimeconstantvelocity,thevelocityhasbeenestimatedusingalinearregressionmodel.Astheycontainhighamountsofoutliersarobustestimatorwaschosenwithahighbreakingpoint(upto50percent).Theevaluationhasshownthatthetimeseriescontainupto23percentofblunderswhichwoulddecreasethereliabilityofvelocityestimation.

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s 9. Waterandlandresourcesindevelopingcountries:towardsinnovativemanagementandgovernanceHans Hurni, Urs Wiesmann, Thomas Breu

NCCR North-South; Centre for Development and Environment; Swisspeace Foundation; Swiss National Science Foundation; Swiss Agency for Development and Cooperation; Commission for Research Partnerships with Developping Countries (KFPE)

9.1 EhrenspergerA.:BioenergyinAfrica:OpportunitiesandthreatsofJatrophaandrelatedcrops

9.2 Exarchou J., SalimN. :WaterGovernance as a tool to ensure sustainable and securehumandevelopment, in theMiddleEast

9.3 GoetschelL.,PéclardD.:Conflictsandnaturalresources.Researchresultsandoutlook

9.4 LinigerHP.,SchwilchG.,MekdaschiStuderR. :Localandregionalsustainablelandmanagementoptionsbasedonassessedexperiences

9.5 MaselliD.,Ur-RahimI.:Fromatechnocratictoacustodianshipapproach:PuttingherdersatthecentreofpasturemanagementinKyrgyzstan

9.6 MejriZ.,BenHamzaC.,HatiraN.,AbidiR.:Repartitionethydrochimiedesaquiferesdel’extremitenordoccidentalesflyschnumidien,(Tunisieseptentrionale)

9.7 NotterB.,HurniH.,AbbaspourK.:UsingtheSWAThydrologicalmodeltoquantifywater-relatedecosystemservicesinalargeEastAfricanwatershed

9.8 ThüringM.,TrotmanA.,MooreA.:CaribbeanWaterMonitor:Smallislandstates,waterresourcesandclimatechange

9.9 WolfgrammB., Bühlmann E., LinigerHP.,HurniH. : GIS-based decision support for soil conservation planning inTajikistan

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BioenergyinAfrica:OpportunitiesandthreatsofJatrophaandrelatedcrops

EhrenspergerAlbrecht1

1 Centre for Development and Environment, Universität Bern (albrecht.ehrensperger@cde.unibe.ch)

Thedevelopmentofthebioenergysectorispushedworldwideinfaceofclimatechangeandtheexpectedshortageoffossilfuels.Biofuelshavethepotentialtoraiseexportrevenues,tocreatenewjobsandtodevelopindustriesindevelopingcoun-tries,butalsotoreducedependencyonoilimports(KOJIMAandJOHNSON2005,SIMS,HASTINGSetal.2006).Morebiofuelalsomeanslessuseoffossilfuels.Modelsshowthatthiswouldhelpreducethepriceofoil,tothebenefitofotherdevelopingcountriesthatcannotgrowbiofuelfeedstock.Asaconsequenceoftheseenvironmentalandeconomicopportunities,pro-ductionofbio-ethanolfromcornandsugarcaneandproductionofbiodieselfromrapeandsoyoilrapidlygrewoverthelastyears.However, current researchunveiled significant impactsofbioenergyon theenvironment (ZAH,HISCHIER,GAUCH,LEHMANN,BÖNIandWÄGER2007;SCHARLEMANNandLAURANCE2008),onlandusecompetitionbetweenenergyandfoodcrops(REINHARDandZAH2008;SEARCHINGER,HEIMLICHetal.2008),aswellasastrongdependenceofthebiofuelsmarketonsubsidies(STEENBLIK2007).

ThisBioenergyinAfrica(BIA)projectaddressesimportantissuesofsustainabledevelopmentinconnectiontotheproductionofbiofuels,likefoodsecurity,povertyalleviation,ruraldevelopmentandnaturalresources.Byusingasystemicapproach,the project will provide pathways towards realistic and sustainable production of bioenergy in Eastern Africa. The ap-proachesbywhichtheopportunitiesofbiofuelproductioncanbemaximisedanditsthreatsminimisedareatthecoreofthis approach.They include landuse, livelihood strategies,natural resourcesmanagementandpolicies. Specifically, theprojectlooksatfouraspectsofbiofuelproduction(seefigurenextpage):

1. Cropgrowthandprocessing:AssessingsustainablebioenergyproductionpotentialsandprocessingofJatrophabio-massindifferentproductionsystemsandunderdifferentenvironmentalandculturalsettings.

2. Impactsofbiofuelproduction:Assessingthesocio-economicandenvironmentalimpactsofbiofuelproductioninlocalcontextswithafocusonlocallivelihoodsandnaturalresourcesdynamics.

3. Globalpolicy,tradeandcertification:Assessingtheinfluenceofexternalsocio-politicalandeconomicdecision-makingprocessesontheregionalandlocalbiofuelproductionprocessesinEasternAfrica.

4. PotentialsofbiofuelinEasternAfrica:Upscalingfindingsinviewofprovidingrelevantdecision-makingandplan-ningtoolsatthenationalandregionallevelsinEasternAfrica.

Theintegrationofprojectresultsataregionalscalewillprovidehighlyrelevantbaselineinformationforabroadrangeofpotentialusers.Concreteimpactsareexpectedasfollows:

• Atthelocalscale:Enhancedcapacityoffarmersincropproductionandbiofuelprocessing.• Atthesub-nationalscale:Enhancedcapacityofconcernedgovernmentalofficesatdistrictandprovinciallevels,to

beachievedagainviasupporttotheextensionservices.• Atthenationalandregionalscales:Betterandmoresustainableplanningandpolicymakinginrelationtobioenergy

production.StrengtheningoftheEasternAfricanRegionthroughadvocacyofitsneeds,prioritiesandpotentials.• Atthegloballevel:Impactontheglobaldiscourseonbiofuel

REFERENCESKojima,M.andT.Johnson(2005).PotentialforBiofuelsforTransportinDevelopingCountries.Washington,WorldBank:150Reinhard, J. andR. Zah (2008). "Consequential Life Cycle Assessment of the Environmental Impacts of an Increased

Rapemethylester(RME)ProductioninSwitzerland."Biomass&Bioenergy.Scharlemann,J.P.W.andW.F.Laurance(2008)."Howgreenarebiofuels?"Science319:43-44.Searchinger,T.,R.Heimlich,R.A.Houghton,F.Dong,A.Elobeid,J.Fabiosa,S.Tokgoz,D.HayesandT.-H.Yu(2008)."UseofU.

S.Croplands forBiofuels IncreasesGreenhouseGasesThroughEmissions fromLandUseChange." Science319 (5867):1238-1240.

Steenblik,R. (2007).Government support for ethanol andbiodiesel in selectedOECDcountries -A synthesis of reportsaddressing subsidies forbiofuels inAustralia,Canada, theEuropeanUnion, Switzerlandand theUnitedStates,GSI -GlobalSubsidiesInitiative:82.

Sims,R.,A.Hastings,B.Schlamadinger,G.TaylorandP.Smith (2006).Energycrops:current statusand futureprospects.GlobalChangeBiology.

Zah, R., R.Hischier,M.Gauch,M. Lehmann,H. Böni and P.Wäger (2007). Life CycleAssessment of Energy Products:Environmental ImpactAssessmentofBiofuels.Bern,Bundesamt fürEnergie,Bundesamt fürUmwelt,Bundesamt fürLandwirtschaft:20.

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WaterGovernanceasatooltoensuresustainableandsecurehumandevelopment,intheMiddleEast

ExarchouJoanna1,SalimNidal2

1 Global Institute for Water Environment and Health (GIWEH), Geneva- Switzerland.www.giweh.ch2 Global Institute for Water Environment and Health (GIWEH), Geneva- Switzerland.www.giweh.ch

AlargeproportionofthewaterresourcesintheMiddleEastistrans-boundaryandfinalarrangementsonwaterallocationbetweendifferent countries in the region arenot yet inplace for “fair and equitable apportionment”. TheMiddle Eastregion’snaturalwaterisnotonlythreatened,itisalsothreatening!

Waterqualityandquantityarethemainchallengesoftheregion.Beyondthechallengesrelatedtothemanagementofre-sourcescarcitytherearehydro-politicalandtrans-boundaryconsiderations.Themajorityofthewaterresourcesintheregi-on is riversandaquifers thatcutacrossborders.Other thanthe fact that thisoftenhinders theefficientandequitablemanagementofthiswater,theprospectofwitnessingseriouswaterconflictsindifferentpartsoftheregionisveryreal.

Whenwaterresourcesinonecommunitybecomescarceorthreatened,theeconomic,socialandenvironmentalrisksincre-aseforeveryone.Thus,aproactiveintegratedmanagementapproachisneededtobalancethecompetingneedsforthisli-mitedresource.“WaterSustainability”isacollaborativecommunity-driveninitiative,whichrequirestheactiveparticipati-onofallmembersinthecommunity.Itseekstoestablishnewcreativeandcoordinatedwatermanagementstrategiesbasedonvalueadditionandsecurityforallstakeholdersinthecommunity.

Thekeyaspectstobeconsideredforthefutureprospectivearetheroleofgovernance,whilegovernanceisconsideredasaprocess,soitisimportanttoknow'how'itisdone.Rulesarebroughtinanddecisionsaremade.Fromtheotherside,gover-nanceisaproduct(e.g.goodgovernance,gooddecisionmaking,badgovernance).

Oneoftheaimsoftheregionistoimprovesustainabilitythroughbetterwateruseefficiencyandconservation.Watereffi-ciencycanbeimprovedbyadoptingstructuralmeasureslikeimprovingtechnologiesandnon-structuralmeasuressuchaswaterpricing,awarenessraising,etc.Thesecondlevelofefficiencyisrelatedtotheallocationandre-allocationofwaterresourcestospecific,higher-valueusesandmoreequitableusebyallstakeholders.Thehighestlevelofefficiencyisrelatedtotheinter-basintradeofwater.Aswaterisquiteabulkyitemtotransport,tradingwaterinitsrealformiscostly,whichisthereasonwhytheconceptofvirtualwatermightcomesintopicture.

Governanceinitsseveralcontextssuchas(corporategovernance,internationalgovernance,nationalgovernanceandlocalgovernance)isneededinthearea.

Cooperationinthemanagementofscarcityandqualitydoesnotonlyoccuratthegovernmentlevelbutalsothatofcorpo-rations.TheCEOWaterMandatewithintheGlobalCompactisanopportunityatthehighestlevelsofmanagementtocom-mittotheimprovementofwateruseefficiency.

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ConflictsandNaturalResources.ResearchResultsandOutlook

LaurentGoetschel1,DidierPéclard1

1 Swisspeace Foundation, Sonnenbergstrasse 17, CH-3000 Bern 7 (laurent.goetschel@unibas.ch)

Therelationsbetweennaturalresourcesandconflictshavealonghistory.Forcenturies,societieshaveusedcertainnaturalresourcestopursuetheirinterestsandpoliticalgoals.Untiltheendofthe18thcentury,forexample,woodwasofcrucialimportancetotheseapowers.Today,oilisintheheadlinesofthemediaworldwideasanindispensablecomponentofsu-perpowerpolitics,butalsoasacauseofconflict.Thissituationisreferredtoasgeopoliticsofconflictsconnectedwithna-turalresources(so-calledresourceconflicts;seeLeBillon2005).However,statesdonothavethemonopolyoverappropriationofnaturalresourcesforpoliticalormilitarypurposes.Controlovernaturalresourcesortheiruseisalsoasignificantfactorwithregardtotensionsandevenconflictsbetweensocietalgroups–independentlyofwhethertheresourcesatstakearenon-renewable(suchasdiamonds)orrenewable(suchaswaterorsoil).Despitetheirlongexistence,therelationsbetweennaturalresourcesandconflictsremainproblematicandmustbecriticallyscrutinised.Basedonvariouscasestudieswede-monstratethatthenotionofadirectcausallinkbetweentheenvironmentandconflicts,althoughwidespreadinthescien-tificliterature,hasnorealempiricalbasis.Likewise,it isnecessarytoquestiontheheuristicsignificanceofthisclassicalperspective:concentratingonecologicalcausalrelationsbearstheriskofnotpayingdueattentiontotherealhistorical,politicalandeconomicdimensionsoftheseconflicts.

REFERENCESBaechlerG,BögeV,Klötzli S, Libiszewski S, SpillmannKR.1996.Kriegsursache Umweltzerstörung. Ökologische Konflikte in der

Dritten Welt und Wege ihrer friedlichen Bearbeitung.ENCOPVol.1.ZurichandChur:Rüegger.BichselC.2006.Dangerous Divides: Irrigation Disputes and Conflict Transformation in the Ferghana Valley[PhDdissertation].Bern:

InstituteofGeography,UniversityofBern.BrockL.1998.UmweltundKonfliktiminternationalenForschungskontext.In: CariusA,LietzmannKM,editors.Umwelt und

Sicherheit. Herausforderungen für die internationale Politik.Berlin:Springer,pp37–56.CariusA,BaechlerG,PfahlS,MarchA,BiermannF.1999.Umwelt und Sicherheit: Forschungserfordernisse und Forschungsprioritäten.

Berlin:Ecologic.EnvironmentalChangeandSecurityProject (ECSP). TheWoodrowWilson InternationalCenter for Scholars.http://www.

wilsoncenter.org/ecsp;accessedon9September2009.HagmannT.2005.Confrontingtheconceptofenvironmentallyinducedconflict.Peace, Conflict and Development6:1–22.LeBillonP.2005.Thegeopoliticaleconomyof‘resourcewars’.In: LeBillonP,editor.Geopolitics of Resource Wars.Londonand

NewYork:FrankCass,pp1–28.MasonSA.2004.From Conflict to Cooperation in the Nile Basin: Interaction between Water Availability, Water Management in Egypt and Sudan, and International Relations in the Eastern Nile Basin. Zurich: Center for Security Studies, Swiss Federal Institute ofTechnologyZurich

9.4

Localandregionalsustainablelandmanagementoptionsbasedonassessedexperiences

LinigerHanspeter1,SchwilchGudrun1,RimaMekdaschiStuder1

1 Centre for Development and Environment, University of Bern, Hallerstrasse 10, 3012 Bern, Switzerland (hanspeter.liniger@cde.unibe.ch; gudrun.schwilch@cde.unibe.ch; rima.mekdaschi_studer@cde.unibe.ch)

SustainableLandManagement(SLM)usesalltypesoflandresources(soils,water,animalsandplants)fortheproductionofgoodstomeetchanginghumanneeds,whilesimultaneouslyensuringthelong-termproductivepotentialoftheseresourcesandensuringtheirenvironmentalfunctions.Watermanagementcannotbeseparatedfromlanduse,thusallSLMtechnolo-giesarerelatedtowater,bycontrollingsurfacerunoffandincreasinginfiltration,andasaresult,storemorewaterinthesoil.Withoutconservationmeasuresthecombinedwaterlossthroughrunoffandevaporationoftenleaveslessthanhalfoftherainfall–orirrigatedwater–availableforcropsorothervegetation.

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iesDependingontheclimate,twomajorcategoriescanbedifferentiated:Inhumidenvironmentssoilerosionandsoilfertility

declinearecommoncausesoflanddegradation.Theimplicationisthatconservationmeasureshavetosolvetheproblemofexcesswaterand its safedrainageeither throughthesoilprofileoronthesurface.Here, themainaimis toreducetherapidrunoffthatcausessheet,rillandgullyerosionon-siteandflooding,sedimentationandpollutionofriversandwaterreservoirsoff-site (downstream).PotentialSLMtechnologies includevegetativemeasuressuchasgrassstrips,greencover,agroforestrysystemsorstructuralmeasuressuchasterraces,gullyrehabilitation,etc.Insub-humid,semi-aridandaridre-gions,thesameproblemsmayoccurthrougherraticrainfall,butthemainfocusisonwaterconservationandimprovedwateruseefficiency,e.g.throughinsituaccumulationofsoilmoistureandreductionofthewaterlossesbyrunoffanddirectevaporationfromthesoil,orthroughwaterharvesting.Exampleshereincludeconservationagriculture, improvedcover,stonelines,plantingpitsandbasins,areaenclosureandassistednaturalregeneration,etc.SuccessfulSLMtechnologiesofteninvolvecombinedmeasures,forexamplestructurestocollectwateraswellasagronomicmeasurestoreducerunoffandevaporationlosses.

Worldwide, therearenumerouspositiveexperiencesof sustainable landmanagement.Thesecounter theprevailingandpessimisticviewthatlandandenvironmentaldegradationisinevitableandcontinuous.WOCAThasdevelopedaninterna-tionallyrecognized,standardisedmethodologyinvolvingasetofthreequestionnairestodocumentrelevantaspectsofSLMtechnologiesandapproaches,includingareacoverage.Acomputer-baseddatabasesystemfacilitatesdataentry,retrievalandevaluation.ApartfromthecasesdocumentedthroughWOCAT(www.wocat.org)andelsewhere,thevastbodyofknowledgeandwealthofexperienceinSLMmadeeitherbyprojectsorthroughinnovationsandinitiativesbythelandusersthemselvesremainsscatteredandlocalised.ThereisstillarichuntappedSLMdiversitythatisnotreadilyavailabletolandusers,thosewhoadvisethem,orplannersanddecisionmakers.Thusthebasisforsounddecisionmaking(forup-scaling)islackingandmistakesarebeingrepeated.TheWOCATtoolsprovideauniquemethodforthecomprehensivedocumentation,monitoring,evaluation and dissemination of SLM knowledge from land users, SLM specialists and researchers from different disci-plines.

AnewmethodologyhasbeendevelopedfortheselectionofSLMstrategies,combiningacollectivelearninganddecisionapproachwithevaluatedpracticesdocumentedbyWOCAT.Aconciseprocessofthreepartsinvolvingallstakeholdersstartswithidentifyinglanddegradationandlocallyappliedsolutionsinastakeholderworkshop.InthesecondpartlocalsolutionsareassessedwiththestandardisedWOCATevaluationtool,andinthethirdpartpromisingstrategiesforimplementationarejointlyselectedwiththehelpofadecisionsupporttool.Facilitatedbyamoderator,participantsconductmulti-criteriaevaluationtorankexistingandpotentialSLMstrategiesforfieldtrials.Thisinvolvesstakeholdersidentifyingandweighingrelevantcriteria(e.g.technicalrequirements,costsandbenefits,socialacceptability,etc.).Anoptioncanonlybeconsideredsustainableifitsevaluationis(moreorless)positivewithrespecttoallthreedimensionsofsustainability:economic,eco-logical,andsocio-cultural.Thus,thenegotiatedSLMoptionhastopayoffforlandusersimplementingit,hastohavepositiveimpactsonlandresources(includingsoil,water,vegetation,fauna),andhastobeacceptabletolocalactorsbyfittingintotheirsocio-culturalcontextandpractices.

However,SLMisoftenbeyondthemeans,responsibilityanddecision-makingpowerofindividuallandusers.Properplan-ningincludesbothlocalparticipation(bythestakeholders)andregionaloverallplanningwhereon-siteandoff-siteimpactsandtheirinteractionsareconsideredandregulated.Thisismostimportantwithregardtowatersheds,whereitcaninvolvedistantcommunitiesandaffecttheirlocallanduseplanning.Toolittleconsiderationhasbeengiventoproperassessmentofon-siteandoff-sitelanduseinteractionsthatleadtoregionalandglobaldamageorbenefits.AreaswithlanddegradationandgoodSLMpracticesneedtobeidentifiedandtheimpactsassessed,forwhichtheWOCATmappingtoolwasdeveloped.Itprovideskeyinformationfordecisionmakingatlocal,regionalandnationallevel,aboutwhereinvestmentscanbestbemade,andaboutwhichSLMpracticeshavethebestpotentialtospread.

REFERENCESWOCAT(WorldOverviewofConservationApproachesandTechnologies).2007:WheretheLandisGreener.Casestudiesand

analysisof soil andwater conservation initiativesworldwide.Editors: Liniger,H. andCritchley,W.CTA,Wageningen(Netherlands).

Schwilch,G.,Bachmann,F.,Liniger,HP.2009:AppraisingandSelectingConservationMeasurestoMitigateDesertificationandLandDegradationBasedonStakeholderParticipationandGlobalBestPractices.LandDegradation&Development,20,308–326.

Liniger,HP.&Critchley,W., 2008: SafeguardingWaterResourcesbyMaking the LandGreener:KnowledgeManagementthroughWOCAT.In:Bossio,D.&Geheb,K.(eds):ConservingLand,ProtectingWater.CABIWallingford.

Liniger,HP.&Schwilch,G.,2002.EnhancedDecision-MakingBasedonLocalKnowledge-WOCATMethodofSustainableSoilandWaterManagement.MountainResearchandDevelopment,22(1):14-18.

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FromaTechnocratictoaCustodianshipApproach:PuttingHerdersattheCentreofPastureManagementinKyrgyzstan

DanielMaselli1,Inam-ur-Rahim2

1 Centre for Development and Environment, Universität Bern, Hallerstrasse 10, CH-3012 Bern and University of Central Asia, Bishkek Kyrgyzstan, and Swiss Agency for Development and Cooperation, Bern (daniel.maselli@deza.admin.ch)2 Centre for Development and Environment, Universität Bern, Hallerstrasse 10, CH-3012 Bern, University of Central Asia, Bishkek Kyrgyzstan (irahim33@yahoo.com)

InthecontextofresearchledbytheNCCRNorth-SouthandtheTPP‘PastoralProductionSystems’inCentralAsia,anewparticipatoryapproachandmethodologyhasbeentestedwherelocalherdersareactivelyinvolvedinassessing,monitoringandmanagingpastures.SofartheassessmentofpastureconditionsinCentralAsiahasbeencarriedoutbyspecialistsem-ployedbystateentities.Basedonperiodicfieldvisits,mapsindicatingthepotentialfodderproductionandcarryingcapac-ityhavebeenestablishedandweremeanttobekeptup-to-date.However,thesemapsappeartobehardlyeverusedbyherd-ersandvillageadministrationsandup-datingisbeinghamperedbylackoffinancialandhumanresourcessinceindepen-dence.

BasedonexperiencesfromnorthernPakistan,anewapproachhasbeentestedinthreedifferentvillagesinKyrgyzstan.Thefundamentalchangeislinkedtotherecognitionoflocalherdersastherealmanagersandfuturecustodiansofthepastures.Theinnovativemethodologyintegratesbiophysical,socio-economicandinstitutionalelementsintoaparticipatorypasturemanagementplanningsystem.Astheseelementsinteractinahighlydynamicandinterdependentmanner,changeinanyoneisboundtomodifytheresultingland-usestrategy.Thisfactleadstoaneedformoreappropriatecontextspecificap-proachesforpasturemanagementtosecuretheappropriateuseofpastoralresources.

Afteranexploratoryintegratedsurveymeanttoidentifytheappropriateplanningunits,thelocalherdersareguidedinse-lectingappropriate indicator species forpasturemonitoring. Inparallel thecurrent seasonaloccupationandutilizationpatternisassessed.Herdersaretrainedtoevaluategrazinglandconditions.Duringthisprocess,thetrainedherdersassesstherelativeavailabilityofkeyindicatorspecies,thecalculatedstockingcapacityofdifferentmanagementunits,andthecurrentstocking.Basedonthisunderstandingajointrehabilitationorsustainablemanagementstrategycanbedevisedus-ingamulti-stakeholderprocessinwhichlocalauthoritiesareintegrated.

Themaininnovationresidesinsimplifyingandmodifyingtheclassicalconservationmonitoringtoolstoaherder-monitor-ingtoolinatransitioncontextbasedonparticipationandtakingintoconsiderationlocal/traditionalknowledge.

REFERENCESAnnaCarr andRogerWilkinson (2005) BeyondParticipation:BoundaryOrganizationsas aNewSpace for Farmers and

ScientiststoInteract.JournalofSociety&NaturalResources,Volume18,Issue3February2005,pages255–265vanNoordwijk,M., T. P. Tomich, and B. Verbist (2001)Negotiation supportmodels for integratednatural resource

management in tropical forestmargins.ConservationEcology5(2):21. [online]URL:http://www.consecol.org/vol5/iss2/art21/

DaleDore(2001)TransformingTraditionalInstitutionsforSustainableNaturalResourceManagement:History,NarrativesandEvidence fromZimbabwe'sCommunalAreas.AfricanStudiesQuarterly 5,no.3: [Theonline Journal forAfricanStudies]URL:http://web.africa.ufl.edu/asq/v5/v5i3a1.htm

RihoyE (1995) TheCommonsWithout theTragedy: Strategies forCommunityBasedNaturalResourcesManagement inSouthernAfrica.ProceedingsoftheRegionalNaturalResourcesManagementProgrammeAnnualConference.Lilongwe,Malawi:SADCWildlifeTechnicalCoordinationUnit,.

DerekArmitage1(2005)AdaptiveCapacityandCommunity-BasedNaturalResourceManagement.JournalofEnvironmentalManagementVolume35,Number6/June,2005pp703-715

TerryHillman, LinCrase1,BrianFurze1, JayanathAnanda1andDarylMaybery1 (2005)MultidisciplinaryApproaches toNaturalResourceManagement.JournalofHydrobiologia.pp99-108

Inam-ur-Rahim andDanielMissili (2004) Improving sustainable grazingmanagement inmountain rangelands ofHindukushHimalayas:AninnovativeparticipatoryassessmentmethodinNorthernPakistan.MountainResearchandDevelopment,Vol24No:2(124-133)

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RepartitionEtHydrochimieDesAquiferesDeL’extremiteNordOccidentalesFlyschNumidien,(TunisieSeptentrionale)

MEJRIZouhaier1,BENHAMZAChedhly,HATIRANouri2etABIDIRiadh;

Unité de Recherche – Géologie des Ressources Naturelles, Département des sciences de la terre, Faculté des sciences de Bizerte, Jarzouna-Bizerte.7021. Tunisie. 1mejrizouhair@yahoo.fr; 2nouri_hatira@yahoo.fr

LaregiondeKromerie,situéeenrivegauchedel’OuedMejerda,secarcteriseparunréseauhydrographiquedenseetramifié,unetopographietrèsaccidentéeetunepluviométrieannuelle1500mmLasérieNumidiennedelarégiondeKroumerie(Tunisieseptentrionale)estsubdiviséeentroistermeslithologiquesdistincts(Rouvier,1977).Cettesériereprésenteunpotentielréservoirhydrogéologiqueimportantessentiellementdanslemembremédiangréseux(Kroumerie).

LazonenaturelledelaKroumerieestdécoupéeparunréseaud’accidentsmajeursdisposéesendécrochements-chevauche-mentsdedirectionNE-SWàNNE-SSWsenestreetsubE-Wdextre(BenAyed,1994).Cettestructurationestàl’origine,d’unepart,delacompartimentationdesgrèsetdel’isolementdifférentieldesréservoirsgréseuxetd’autrepart,delacréationd’unefracturationmultidirectionnelletardiveentraînantuneaugmentationpréférentielledelaporositéetdelaperméa-bilitédesgrésconsolidésdesflyschsnumidiensduMaghreb(Johanssonetal.,1998)(Fig.1).Lesréservoirsgréseuxsontcaractérisésparunedynamiquesédimentairereprésentéepardescorpslenticulaires,deschen-aux,slumps.Avecdesbioturbations,desfilons;ontétéperturbéparlereplissementd’âgequaternaireancienetd’extrusiondeTriassalifère(Rouvier,1977).L’alimentationderéservoirssefaitparlesfilonsgréseuxquiassurentlajonctiondesdifférentessillsparcourantlesgrésdeKroumerie.

LeseauxsouterrainesissusderéservoirgréseuxdesMogodsmontrentdesfacièshydrochimiquesdetypechloruréetsulfatécalci-magnésienetdetypechloruréetsulfatésodiqueetpotassique.desconcentrationélevaisensulfatesetensodium,avecundégagementd’odeurfétides,aétémanquéesauniveaudecertainscaptagesimplantéssuivantunedirectionpréférenti-elleorientéeNNE-SSW.Toutefois,lacompositionchimiquedeseausouterraines,mémoiredeséchangeseau-roches.Constituéunsupportfiabledelessivageetdedissolutiondeslithosfacièsréservoirs.Larichesseenchlorureetensodiumestdifficileàexpliquersansad-mettrequesetaquifèregréseuxestconnectéàdesfacièsévaporitiqueduTrias.,notammentdusqueunaccidentprofondestinjectéparunendroitpardespointementsvolcaniques.

REFERENCESBenAyed,N.1994.Lesdécrochements-chevauchementsEWetNSconvergentsdelaTunisieseptentrionale:Géométrieet

essai de reconstitution des condition de deformations. Proceedings of the 4Th Tunisian petroleumExplorationconference.E.T.A.P,Tunisie,25-35.

Johansson,M.,Braakenburg,N.E., StowA.V.D. andFaugères J.Cl. 1998.Deep-watermassive sands: facies,processes andchannelgeometryintheNumidianFlysch,Sicily.Sedimentarygeology.115,233-265.

Rouvier,H.1977.Géologiedel’extrêmetunisien:tectoniquesetpaléogéographiessuperposesàl’extrémitéorientaledelachaînemaghrébine,theseDoctoratèsSc.,Univ.PetM.Curie,Paris,France.

Fig.1.CoupegéologiquesimplifiéelastructuredesréservoirshydrogéologiquesdelarégiondesKroumerie(Rouvier,1977)

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UsingtheSWAThydrologicalmodeltoquantifywater-relatedecosystemservicesinalargeEastAfricanwatershed

NotterBenedikt1,HurniHans1,AbbaspourKarim2

1 Centre for Development and Environment, Universität Bern, Hallerstrasse 10, CH-3012 Bern (benedikt.notter@cde.unibe.ch)2 Eawag, Überlandstrasse 133, Postfach 611, CH-8600 Dübendorf

TheEastAfricanPanganiBasin,awatershedofabout43,000km2locatedinTanzaniaandstraddlingthebordertoKenya,ischaracterizedbyanincreasingdemandforwater-relatedecosystemservices.Theseincludedomesticuse,agriculture,andhydropowerproduction.Thefinalaimofthestudyistoassesswateravailabilitytosustainecosystemservicesforthecurrentsituationaswellaspossiblefuturescenariosinthebasin.Westartfromtheassumptionthatanecosystemserviceisrealizediftheavailabilityofaresource(likewater)matchesanexistingdemandofanystakeholderintermsofquantity,quality,ti-mingandlocation(Notteretal.[submitted]).

TheSWATmodel(Arnoldetal.1998)canbeusedtoestimatewateravailabilityforunmeasuredlocationsandforhypotheti-calsituations,butunderthegivenassumptionneedstoproduceoutputsforspatialandtemporalunitswithinwhichtheecosystemservicesofinterestaretransferrable.InthecaseofPanganiBasin,amonthlytemporalresolutionandspatialunitscorrespondingtotheintersectionofclimaticzones,subbasinboundaries,andadministrativeunitsattheWardlevelisne-cessary.Anadditionalchallengeinourstudywasthelackofhighqualitydataonclimate,discharge,andwateruse,whichmakesuncertaintyassessmentanimperative.Thementionedchallengesweremetwithacombinationoffivestrategies:

a) Reducingdatalimitationsbycombiningdatasetsfromdifferentsources,e.g.byusingGIStoolstodetermineandimple-mentthebestpossibletechniqueforpre-processingclimaticdatatakingintoaccountelevationeffects;

b) ImplementingminormodificationstotheSWAT2005modelcode(correctionsintheirrigationanddormancyroutines,writingadditionaloutputvariables,introductionofparametersthatallowvaryingmeasuredtime-seriesinputs);

c) Developingasubbasinconfigurationprocedurethattakesintoaccountadministrativeunitsandelevationzoneswhileminimizingthenumberofsubbasinscreated;

d) ApplyingtheSUFI-2algorithm(Abbaspouretal.2007)formodelcalibrationanduncertaintyassessment,andadditional-lyincludinguncertaintyinmeasuredtime-seriesinputslikerainfall,temperature,pointsources,andmaximumalloweddiversionsintheuncertaintyanalysis;

e) Derivingproxiesforwater-relatedecosystemservicesfromSWAToutputs,e.g.wateravailabilityatthe95%reliabilitylevelasaproxyfordomesticwater,numberofmonthsperyearwithoutwaterstressasaproxyforagriculturallysuitableland,ordischargeat75%and95%reliabilitylevelsattopographicallysuitablelocationsasaproxyforhydropowerproduction.

Calibrationandvalidationofmonthlydischargeyieldssatisfactoryresults,withNash-Sutcliffecoefficientsof>=0.5reachedat8of12stations,onaverageabout70%ofmeasureddatabracketedinthe95%predictionuncertainty,andanaveragewidthofthisuncertaintyrangeofabout1.13standarddeviationsofmeasureddata.Waterqualityparameterscouldnotbecalibra-tedforalackofmeasureddata,butuncertaintybandscanbecalculatedbasedonthephysicallyplausiblerangesofparame-terssensitivetowaterquality.

Thecalibratedmodelproducesoutputsforanyrequiredadministrativeunit,climaticzone,orsubbasin,oranycombinationof theseunits. Preliminary results fromecosystem servicequantification for the "current situation" (weather conditionsfrom1981-2005,landuseandsocio-economicdatafrom1997-2002)indicatethatdomestic,andtoalesserextentalsoindus-trialandlivestockwaterdemandsarenearsatisfiedatthe95%reliabilitylevelinthoseDistrictsthatarebetteraccessiblebyroads,probablybecausewaterinfrastructurecanbebuiltandwaterrightscanbeobtainedmoreeasilyintheseareas.Onagriculturallandinthelowlands,wherethereispotentialforexpansion,periodswithoutwaterstressaregreatlyprolongedwhereirrigationisapplied,andproductivitythusenhanced;however,irrigationdirectlyimpactsonhydropowerpotentialbysignificantlyreducingdryseasondischarge.Evaluationofpossiblefuturescenariosandalternativemanagementoptionshasnotbeencarriedoutyetbutisplannedforthecomingmonths.

REFERENCESAbbaspour,K.C.etal.,2007.Modellinghydrologyandwaterquality in thepre-alpine/alpineThurwatershedusingSWAT.

JournalofHydrology,333:413-430.Arnold,J.G.,Srinivasan,R.,Muttiah,R.S.andWilliams,J.R.,1998.LargeAreaHydrologicModelingandAssessmentPartI:

ModelDevelopment.JournaloftheAmericanWaterResourcesAssociation,34(1):73-89.Notter,B.,Hett,C.,Hurni,H.andWiesmann,U.[submitted].Water-andLandCover-RelatedEcosystemServices:Approaches

toQuantificationinEastAfricaandLaos.EcologicalComplexity:ManuscriptNumberECOCOM-S-08-00227.

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CaribbeanWaterMonitor:Smallislandstates,waterresourcesandclimatechange

ThüringManfred1,TrotmanAdrian2&MooreAnthony2

1 Institute of Earth Sciences, University of Applied Sciences of Southern Switzerland, PO Box 72, CH-6952 Canobbio (manfred.thuering@supsi.ch)2 Caribbean Institute of Meteorology and Hydrology, Husbands, BB-23006 Barbados (atrotman@cimh.edu.bb, amoore@cimh.edu.bb)

Thesufficientavailabilityofwaterresourcesisakeyfactorofsuccessforanycommunity.ThisprojectaddressesthechangesintheavailabilityofwaterresourcesintheCaribbeantoday,andtheimpactofclimatechange.Aninternet-basedmonitoringtool–theCaribbeanWaterMonitor-isbeingdeveloped,whichindicatesthecurrentsituationregardingtheavailabilityofwaterontwoislandstatesoftheCaribbean(BarbadosandTrinidad&Tobago).Basedontheinputofclimatedata–mainlyprecipitationandtemperature–thetoolassessesautomaticallythecurrentsituationanddisplays it inacomprehensiveform,suchasmapsortrendgraphs,asdevelopedinaformerprojectfortheCaribbeanislandSaintLucia(Figure1).

Figure1.Theusageofdroughtindices,suchasStandardPrecipitationIndexorDeviationfromNormalareusedassupportinformationin

waterresourcesmanagement(www.droughtinfo.org).

TheCaribbeanWaterMonitorisanessentialtoolforwaterresourcesmanagement,andoffersahelpfordecisionsupportforplanningandmanagingwaterresources.Climatechangewillrequireadaptationstrategies.Thesestrategieswillhavetobeguidedbyassessmentandmonitoringtools,suchastheproposedCaribbeanWaterMonitor.

Thisone-yearprojectisdevelopedincooperationbyaSwissandCaribbeanresearchpartnerwithcomplementarycompe-tences,andfinancedbyKFH-DEZA.

InourposterweshowthecurrentstatusoftheprojectonthedevelopmentofmapbaseddroughtandwaterindicesandtheidentificationofclimatechangesignaturesinrainfallrecordsofBarbados.

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GIS-basedDecisionSupportforSoilConservationPlanninginTajikistan

WolfgrammBettina1,BühlmannErik1,LinigerHanspeter1&HurniHans1

1 Centre for Development and Environment (CDE), University of Bern, Hallerstrasse 10, CH-3012 Bern (bettina.wolfgramm@cde.unibe.ch)

Soilerosiononslopingagriculturallandposesaseriousproblemfortheenvironmentaswellasforproduction.Inareaswithhighlyerodiblesoils,suchasthoseinloesszones,applicationofsoilandwaterconservationmeasuresiscrucialtosustain-ingagriculturalyieldsandpreventing/reducinglanddegradation.Thepresentstudy,carriedoutinFaizabad,Tajikistan,wasdesignedtoevaluatethepotentialoflocalconservationmeasuresoncroplandtoprovidedecisionsupportforplanningsustainablelanduseinaspatiallyexplicitmanner.Asamplingdesigntosupportrelativecomparativeanalysisbetweenwell-conservedunitsandotherfieldunitswasestablishedinordertoesti-matefactorsthatdeterminewatererosion,accordingtotheRevisedUniversalSoilLossEquation(RUSLE).Suchfactor-basedapproachesallowreadyapplicationinageographicinformationsystem(GIS)environment.Furthermore,thefactor-basedRUSLEmodelfacilitatesstraightforwardscenariomodelling.High-resolutionQuickbirdsatelliteimagerywasusedtoassesscanopy cover – a major erosion control factor in the model. Standardised questionnaires designed by WOCAT (WorldOverviewofConservationApproachesandTechnologies)wereusedtodocumentlocalconservationmeasures.Thestudyshowedfirstthatassessmentoferosionandconservationinanareawithinhomogeneousvegetationcoverneces-sitatestheintegrationofplot-basedcoverderivedfromhigh-resolutionsatelliteimageryinordertoenableplot-wiseconser-vationplanning.Furthermore,thoroughfieldassessmentsshowedthat25.7%ofcurrenttotalcroplandiscoveredbyconservationmeasures(terracing,agroforestryandperennialherbaceousfodder).Assessmentoftheeffectivenessoftheselocalmeasures,combinedwiththeRUSLEcalculations,revealedthatcurrentaveragesoillosscouldbereducedbylow-costmeasuressuchascontour-ing(by11%),fodderplants(by16%),anddrainageditches(by55%).Moreexpensivemeasuressuchasterracingandagrofor-estrycanreduceerosionbyasmuchas63%(forterracing)and93%(foragroforestrycombinedwithterracing).Indeed,scenariorunsfordifferentlevelsoftolerableerosionratesshowedthatmorecost-intensiveandtechnologicallyad-vancedmeasureswouldleadtogreaterreductionofsoilloss.However,giventheeconomicconditionsinTajikistan,itseemsmoreadvisabletosupportthespreadoflow-costandlabour-extensivemeasures.

REFERENCESBühlmann,E.2006:AssessingSoilErosionandConservationintheLoessAreaofFaizabad,WesternTajikistan.MSc,Centre

ofDevelopmentandEnvironment,UniversityofBern.Liniger,H.P.,andW.Critchley.2007:WheretheLandisGreener.Casestudiesandanalysisofsoilandwaterconservation

initiativesworldwide.Wageningen:TechnicalCentreforAgriculturalandRuralCooperation.Renard,K.G.,G.R. Foster,G.A.Weesies,D.K.McCool, andD.C. Yoder. 1997: Predicting soil erosionbywater:A guide to

conservationplanningwiththeRevisedUniversalSoilLossEquation(RUSLE).AgricultureHandbook703.Washington,DC:USDA.

Shi,Z.H.,C.F.Cai,S.W.Ding,T.W.Wang,andT.L.Cho.2004:SoilconservationplanningatthesmallwatershedlevelusingRUSLEwithGIS:AcasestudyintheThreeGorgeAreaofChina.Catena55(1):33-48.

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boundaries crossed and encountered in the Quaternary research +

12. Biological, physical and chemical processes in soilsJudit Becze-Deak + Samuel Abiven, Pascal Boivin, Elena Havlicek, Claire Le Bayon

Swiss Society for Quaternary Research (CH-QUAT) Société Suisse de Pédologie / Bodenkundliche Gesellschaft der Schweiz / Società Svizzera di Pedologia

10.1 AbivenS.,AndreoliR.:Decomposabilityofpyrogeniccarbonmixedtodifferentorganicsubstrates

10.2 Batlle-AguilarJ.,BrovelliA.,PorporatoA.,BarryD.A.:Modellingofmechanismsaffectingnitrogenandcarboncyclesinsoilssubjecttolandusechange

10.3 BreiderF.,AlbersC.,HunkelerD.,JacobsenO.S.:Carbonisotopesignatureofbiogeogenictrichloromethane:atooltodiscriminateanthropogenicandnaturalsourcesinsoils

10.4 BroennimannC.,AskarinejadA.,KienzlerP., SpringmanS., Tacher L. : Porewaterpressuremodelling in a rainfalltriggeredshallowlandslide:thesprinklingexperimentinRüdlingen,CantonSchaffhausen

10.5 CastelltortS.,GredigG.:Controlsontheformofbarsinbraidedrivers

10.6 ChappatteD.,VerrecchiaE.:Discretesimulationofbiogeochemicalexchangesinamicrobialmat

10.7 CommentN.,PinardG.,AbivenS.,AdatteT.,GobatJ.-M.,VerrecchiaE.:Reconstructionofpastvegetationsuccessionondeveloppingpodzolsusingorganicandmineralspecificmarkers

10.8 EhrhardtF.,MateraV.,AdatteT.,VerrecchiaE.:Etudedeladynamiquedesélémentstracesmétalliquesenforêtpéri-urbaine(Isle-Adam,Vald’Oise,France):approcheécosystémique

10.9 Füllemann F., Milleret R., Capowiez Y., Le Bayon R.-C., Gobat J.-M., Boivin P. : Soil porosities as engineered byearthwormsmicrocosmexperimentwithtomographyandshrinkageanalysisassessment

10.10 GlurL.,WirthS.B.,AnselmettiF.S.,GilliA.,HaugG.H.:FloodAlp!FrequencyandintensityofextremefloodsintheAlpsthroughtheHolocene

10.11 GrafPannatier,E.,SchmittM.,ThimonierA.,WaldnerP.:EffectsofatmosphericdepositionofacidcompoundsandnitrogenonsoilsolutioninSwissforests

10.12 HeerA.,Hajdas I.,SteffenD.,PreusserF.,VeitH. :OSL-basedchronologyof thepostglacialbeachplainNEofLakeNeuchâtelonSwissPlateau:Problemsandpossiblesolutions.

10.13 HeimA.,HofmannA.,MiltnerA.,ChristensenB.T.,SchmidtM.W.I.:Isthemineralphaseresponsibleforstabilizinglignininsoils?

10.14 HengartnerP.,AbivenS:Pyrogeniccarbonsolubilityinthesoils:quantitativeandqualitativeapproaches

10.15 HippeK.,KoberF.,ZeilingerG.,Ivy-OchsS.,KubikP.W.,SchlüchterC.,WielerR.:Quantifyingratesofsurfacedenuda-tionattheeasternAltiplanomargin,LaPazregion,Bolivia

10.16 KoberF.,AbbühlL.,DürstM.,Ivy-OchsS.,SchluneggerF.,KubikP.W.:Theshapeversustheprocessesofalandform–theHörnliregion,NE-Switzerland

10.17 Kohler-MilleretR.,LeBayonC.,BoivinP.,GobatJ.-M.:Earthworm,mycorrhizaandrootinteractions:effectsonsoilphosphorusnutrientstatusandsoilstructure

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10.18 MatileL.,AchermannM.,KrebsR.:EntwicklungundAnwendungeinerGrobscreening-MethodezurUntersuchungdesAbbauzustandesvonMoorbödenamBeispieldesLobsigensees

10.19 Mavris Ch., Egli M., Plötze M., Blum J., HaeberliW. : Initial Stages Of Soil And Clay Minerals Formation In TheMorteratschProglacialArea(UpperEngadine,Switzerland)

10.20 MeyerC.,LüscherP.,SchulinR.:RegenerationofmechanicallyloadedsoilsunderskidlanesbyplantationofAlnusglutinosa

10.21 PichlerB.,SchmidtH.-P.,BoivinP.,AbivenS.:Characterizationofbiocharandtheirimpactonsoilfertility

10.22 PrudatB.,AdatteT.,HassounaM.,GobatJ.-M.,VerrecchiaE.:Rock-EvalPyrolysistodeterminestableorganicMatterinirrigatedsandySoilsfromPalmOrchards

10.23 SastreV.,LoizeauJ.-L.,GreinertJ.,NaudtsL.,ArpagausP.,AnselmettiF.,WildiW.:MorphologyandrecenthistoryoftheRhoneRiverDeltainLakeGeneva(SwitzerlandandFrance)

10.24 SchwanghartW.,FrechenM.,KlingerR.,SchüttB.:GeomorphologicaldriversofHoloceneenvironmentalchangeinMongolia

10.25 SinghN.,AbivenS.,BoivinP.,SchmidtM.W.I.:Moistureandtemperatureeffectsofcharinaforestsoil

10.26 StuderM.,SchneiderM.,MorenoJ.M.,RescoV.,AbivenS.:Atooltoestimatefireintensityandchemicalstructureofblackcarboninputsintosoil

10.27 WangG.,OrD.:Hydrationeffectsonmicrobialmotilityandcoexistenceonunsaturatedroughsurfaces

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Decomposability of pyrogenic carbon mixed to different organic substrates

AbivenSamuel1,AndreoliRomano1

1SoilScienceandBiogeography,DepartmentofGeography,UniversityofZurich,Winterthurerstrasse190,CH-8057Zürich(Samuel.abiven@geo.uzh.ch)

Inarecentstudy,Wardleandal.(2008)observedthatthepresenceofpyrogeniccarbonenhancedthedecompositionoflitterorganicmatterinaborealecosystem.Thepyrogeniccarbon(PyC)correspondstothebiomassresiduesaftertheirincomple-tecombustion.Itpresentsparticularfeaturesregardingitbiological,chemicalandphysicalstabilityandmightplayamajorroleintheorganicmatterprocessesofsoils.

Thedecompositionoforganicsubstratesmixturescouldbequitedifferentfromthedecompositionofthesamesubstratesconsidered individually. Inmostof thecases, the interactionswithin themixtureendsupwithahigherdecomposition(synergiceffects).Thecaseswhenthedecompositionislowerduetothemixture(antagonisticeffects)orwherenointerac-tioneffects(additiveeffects)werelessreported(GartnerandCardon,2004).These interactionscanbeexplainedby thepresenceof certaincompounds thatmight influence thedecomposition.Forexample,thedegradationofrich-NorganicsubstrateswillmakeavailablemineralNthatcanbeusedbythemicro-organismstodegrademoreN-limitedsubstratesandsowillleadtoasynergiceffect(Handayantoetal.,1997).Onthecontrary,there-leaseofbiocidemoleculeslikepolyphenolsmightaffectthedecompositionofthemixtureandcauseanantagonisticeffect(PalmandRowland,1997).

Inthisstudy,wefollowedtheeffectsoftheinteractionsbetweenPyCandfourdifferentsubstratescontainingdifferentcon-tentinNandpolyphenols.

Theexperimentaldesigncorrespondstoanincubationundercontrolledconditions.Wefollowedindividuallyandinmix-turethedecompositionofPiceaabieswood,charfromthisPiceaabieswoodand4typesoffreshlitter,Picealeaves,ashesleaves,oakbarkandalderleaves,during100daysatconstanttemperature(23°C)andmoisture(fieldcapacity).The4typesoffreshlitterhaddifferentcontentsinN(alder>ash>picea>oak)andinpolyphenols(oak>alder>picea>ash).

Thedecompositionwasestimatedby themineralisedC-CO2measuredby the conductivitymethod (WollumandGomez,

1970).ThesoilusedinthisincubationisaCambisol(4%C,30%clay,pH6.0)sampledunderforest(Laegern,Aargau).

ThedecompositionofthemixtureswithN-richcontentlitter(alderandash)wasmoreimportantthanthemixturecontai-ningoakbarkandpicealeaves(mineralizationbelow10%).

Inallthecases (exampleofthemixtureswithAshleaves, figure1),weobservedamoreimportantdecompositionofthemixturewithwood(synergiceffect)andalowerdecompositionofthemixturewiththechar(antagonisteffect).Thediffe-rencesbetweenthedifferentlitterswererelativetothegeneraldecompositionleveloftheinitialsubstrates,ratherthananyinteractionwithparticularcompounds.

TheseresultsarechallengingthestudyofWardleetal.(2008)andshowtheneedtotakeintoaccounttheinitialqualityofthedecomposingsubstrates.

REFERENCESGartner,T.B.&Cardon,Z.G.2004:Decompositiondynamicsinmixed-speciesleaflitter.Oikos104,230-246.Handayanto,E.,Giller,K.E.&Cadisch,G.,1997:RegulatingNrelease from legume treeprunningsbymixing residuesof

differentquality.SoilBiology&Biochemistry.29,1417-1426.Palm,C.A.&Rowland,A.P.,1997:Aminimumdatasetforcharacterizationofplantqualityfordecomposition.PlantLitter

QualityandDecomposition,DrivenbyNature,edsG.CadishandG.E.Giller,Ch.28,379-392Wardle,D.A.,Nilsson,M.C.&Zackrisson,O.2008:Fire-DerivedCharcoalCausesLossofForestHumus.Science.320,629.Wollum,A.G.&GomezJ.E.1970:AconductivityMethodforMeasuringMicrobiallyEvolvedCarbonDioxide.Ecology.51,155-

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Ash and WoodAsh and CharAsh and Char thAsh and Wood th

Figure1.Cmineralization(expressedas%C-CO2/TotalC)ofthemixtureash–wood(square)andash–char(circle).Theblacksymbolsre-

presentthemeasuredvaluesandthewhitesymbolsthearithmeticaverageofthemineralizationoftheorganicsubstratesdecomposing

separetly(th:theoreticalvalue).

10.2

Modelling of mechanisms affecting nitrogen and carbon cycles in soils subject to land use change

Batlle-AguilarJordi1,BrovelliAlessandro1,PorporatoAmilcare2,BarryD.Andrew1

1Ecological Engineering Laboratory, Institute for Environmental Engineering, École Polytechnique Fédérale de Lausanne, Station 2, CH-1015, Switzerland (jordi.batlle@epfl.ch, alessandro.brovelli@epfl.ch, andrew.barry@epfl.ch) 2 Civil and Environmental Engineering Department, Duke University, Durham, NC-27708, USA (amilcare@pratt.duke.edu)

Inordertomeetdemandsforcrops,pastureandfirewood,therateoflandusechangefromforestedtoagriculturalusessteadily increasedover several decades, resulting in an increased release ofnutrients towards groundwater and surfacewaterbodies.Inparallel,thecontinuousdegradationofnaturalecosystemssuchasriparianzones,contributetodiminishtheircapacitytoprovideecologicalservices, i.e. reducethe impactsofdeleterioushumanactivitiesonbothsurfaceandgroundwater.Landusechangesandrestorationpracticesareknowntoaffectbothsoilnutrientdynamicsandtheirtrans-porttoneighbouringareas.

Biogeochemicaltransformationsinsoilsareheavilyinfluencedbymicrobialdecompositionofsoilorganicmatter.Carbonandnutrientcyclesareinturnstronglysensitivetoenvironmentalconditions,primarilytosoilmoisture.Thisphysicalva-riableaffectsthereactionrateofalmostallsoilbiogeochemicaltransformations,includingmicrobialandfungalactivity,nutrientuptakeandreleasefromplants,etc.Soilwatersaturationisnotconstantneitherintimenorinspace,thusfurthercomplicatingthepicture.Inordertointerpretfieldexperimentsandelucidatethedifferentmechanismstakingplace,nu-mericaltoolsarebeneficial.

Theimpactofhydroclimaticvariability(soilmoistureinparticular)onsoilcarbonandnitrogencycleswashighlightedalongwiththeconsequencesoflandusechangesfromforesttopastureand/oragriculture.Tothisend,amechanisticmodelbasedonthecompartmentmodelofPorporatoet al.(2003)wasdeveloped.Thepredictivecapabilitiesofthemodeltoforecastthe

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ces effectsoflandusechangesovercarbonandnitrogendynamicswereshown,modellingfourdifferentscenarios,intertwining

twodifferentclimateconditions(withandwithoutseasonality)withtwocontrastingsoilshavingphysicalpropertiesthatarerepresentativeofforestandagriculturalsoils.Synthetictimeseriesofprecipitation,andthereforesoilmoistureevoluti-onintime,weregeneratedusingastochasticapproach.Themodelwassubjecttoisothermalconditionsandotherconside-rationssuchasaveragevaluesofcarbonandnitrogenconcentrationsovertherootingdepth.Aswellanaveragemicrobialorganicdecompositionratewasconsidered.Simulationresultsdemonstratedhigherconcentrationsofcarbonandnitrogeninforestssoilsasaresultofhigherlitterdecompositionthaninagriculturalsoils(Figure1).Highfrequencychangesinwa-tersaturationunderseasonalclimatescenarioswereshowntobecommensuratewithcarbonandnitrogenconcentrationsinagricultural soils.Forest soilshavedifferentproperties toagricultural soils, leadingtoanattenuationof theseasonalclimate-induced frequency changes inwater saturation,with accompanying changes in carbon and nitrogen concentra-tions.

Themodelwasshowntobecapableofsimulatingthelongtermeffectsofmodifiedphysicalpropertiesofagriculturalsoilsasaconsequenceoftillage,ploughingandharvesting.Itis,thus,apromisingtooltopredictcarbonandnitrogenturnoverchangesduetochangesinlanduse.Theseresultsencouragefurthermodelimprovementsaimedataccountingforthecom-plexityofthesoilsystemanditsprocessesforbetterunderstandingsoilnutrientsturnover.

Figure1.Simulatedorganiccarbonconcentrationsinthelitterpoolforagriculturalandforestsoilsunderseasonal(leftside)andno

seasonal(rightside)climateconditions.

REFERENCESPorporato,A.,D’Odorico,F.,Laio,F.&Rodriguez-Iturbe,I.2003:Hydrologiccontrolsonsoilcarbonandnitrogencycles.Adv.

WaterResour.,26,45-58.

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Carbon isotope signature of biogeogenic trichloromethane: a tool to dis-criminate anthropogenic and natural sources in soils

FlorianBreider1,ChristianAlbers2,DanielHunkeler1&OleStigJacobsen2

1Center of Hydrogeology, University of Neuchâtel, Rue Emile Argand 11, CH-2009 Neuchâtel (f lorian.breider@unine.ch)2Geological Survey of Denmark and Greenland, Oster Voldgade 10, DK-1350 Copenhagen

Trichloromethane(TCM,CHCl3)hasbeenforlongtimeconsideredasananthropogeniccontaminantknownforitscancero-

geniceffects.TCMissometimesdetectedfarfromanyanthropogenicsourceswithoutanyothercontaminants.Todatemorethan3800naturalhalogenatedorganiccompoundshavebeenidentified(Gribble,2003).ThepresenceofTCMinconiferousforestsoilsandgroundwaterhasbeenwidelydemonstrated.DifferentstudiessuggestthatTCMandotherorganohalogenssuchaschloromethanemaybenaturallyproducedinsoilsbyenzymaticchlorinationofthesoilorganicmatter(Hoekstraetal., 1998).Chloroperoxidase excretedby some fungimayplayamajor role in thebiosynthesisof organohalogens in soil(Hoekstraetal.,1998).

Isotoperatiomassspectrometryisapowerfultooltodeterminetheoriginandthefateoforganiccompoundsintheenviron-ment(Harperetal.,2001).TheaimofthisstudyistodiscriminateanthropogenicandbiogeogenicTCMsourcesusingcom-poundspecificisotopeanalysis.TheisotopicsignaturesofTCMproducedindustriallyandbychlorinationofdifferenthu-micsubstancesandsoilorganicmatterweremeasuredbyGC-C-IRMS.Moreover δ13CvaluesofTCMpresentinforestsoilswerealsomeasuredatdifferentdepthinthreesitesinDenmark.

Allnaturalprecursorsusedgivecomparable δ13CvaluesofTCMwhichareconsistentwithtypicalisotopesignatureofcom-poundsderivedfromplantmaterial(Fig.1).IndustrialTCMisparticularlydepletedin13C( δ13C~49‰vs.V-PDB)comparedtoTCMsynthesizedfromnaturalprecursors( δ13C~33‰vs.V-PDB)(Fig.1).Thereforetheisotopicratioconstitutesagoodindica-toroftheoriginofTCM.

The δ13CvaluesofTCMmeasuredinforestsoilsareinthesamerangeasTCMproducedinlaboratoryfromnaturalprecur-sors.ThisconfirmsthatTCMpresentsinsoilairisbiogeogenic(Fig.2).Thevariationsofthe δ13CvalueswithsoildepthareinverselycorrelatedwiththeTCMconcentrationsprofiles.Indeed,whenconcentrationsofTCMinthesoilairarehigh,TCMisdepletedin13CcomparedtosoillayerspresentinglowTCMconcentrations.Thesevariationsarelikelyduetothecombina-tionofproduction,degradationandtransportprocessesinsoils.Furtherinvestigationsarecurrentlycarriedouttoknowhowclimaticparameterssuchasprecipitation,soilmoistureandtemperaturecaninfluencetheseprocessesandthereforetheisotopicratiosofTCM.

Figure1. δ13C(‰)ofindustrialTCMandTCMsynthesizedfromdifferentnaturalprecursors.HA:humicacid,NOM:naturalorganicmatter

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Figure2. δ13C(a)andconcentrationprofiles(b)ofTCMinsoilairofthreedifferentsites.

REFERENCESGribble,G.W.2003:Thediversityofnaturallyproducedorganohalogens.Chemosphere,52,289-297.Harper,D.B.,Kalin,R.M.,Hamilton, J.T.G.&Lamb,C.2001.Carbon isotope ratios for chloromethaneofbiologicalorigin:

Potentialtoolindeterminingbiologicalemissions,EnvironmentalScienceandTechnology,35,3616-3619Hoekstra,E.J.,DeLeer,E.W.B.&Brinkman,U.A.T.1998:Naturalformationofchloroformandbrominatedtrihalomethanes

insoil.EnvironmentalScienceandTechnology,32,3724-3729.

10.4

Porewater pressure modelling in a rainfall triggered shallow landslide: the sprinkling experiment in Rüdlingen, Canton Schaffhausen

BroennimannCornelia1,AskarinejadAmin2,SpringmanSarah2,TacherLaurent1

1GEOLEP, EPFL, Station 18, 1015 Lausanne (cornelia.broennimann@epfl.ch)2Institut für Geotechnik, ETHZ, Wolfgang-Paulistr. 15, 8093 Zürich

Heavyandlong-termrainfalliswellknownasamajortriggeroflandslidesatdifferentscales.Nevertheless,oftenalackofdatasetscomplicatesadetailedunderstandingofslope’shydrologicalregime.Itisassumedthatforshallowlandslidesthehydrogeologicalroleofthebedrockisdeterminantfortheslopesbehaviour.Inthepresentedstudy,twolandslidetriggeringexperimentswerecarriedoutonadenselyequippedtestsite.Basedona largedataset,a finiteelement flowmodelwaselaboratedtoreconstructtheevolutionofporewaterpressuresintheslopeduringandaftersprinklingtests.

ThesprinklingexperimentwaslocatednearthevillagesRüdlingenandBuchberginthecantonSchaffhausenattheborderoftheriverRhine.Withaslopeinclinationoflocallyupto40°theareaisrathersteepandcharacterizedbycontinuousre-gressiveerosionprocesses(Figure1).Theexperimenttookplaceinaslopeaffectedbyformerslidingprocesseswhichcouldbeverifiedbyseveralmassmovementdepositsof~1mthickness.Duringrainfallevents,forexampleinMay2002,severalshallowlandslidesoccurredintheareaandaffectedafforestedsoilsaswellaswoodlessareas.

Thelithologyintheareaoftheexperimentischaracterizedbyhorizontallylayeredmarlsandsandstonesfromthelowerfreshwater(Aquitanien)andupperseawatermolasse(Burdigalien)overlaidby1-3mofsiltycolluviumandsoil.Formoredetailedlithologicalandhydrogeologicalreconnaissance,a23mdeepboreholewasdrilledabovethetestsite.Thesandstoneispoorlycementedandstronglyaltered.Thisexplainsthelocallyhighhydraulicconductivity(10-2m/s–10-5m/s)measuredin various infiltration testswhichwere carriedout in~3mdeephandaugerboreholes. Furthermore, vertical joints indecametrescaleorientedparalleltotheRhineaffectlocallythehydrogeologicalregimebydrainingeffectivelytheslope.Seasonallycontrolledspringsareobservedalongoutcroppingbedrockabovethetestsite.Thisimpliesthatatalocalscalethebedrockwaterflowsarehighlyheterogeneous.

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The10x30mlargetestsitewithameaninclinationof35°wasequippedamongotherswithpluviometers,tensiometers,decagons, piezometers, deformation probes, electric resistivity tomography instrumentation, acoustic sensors and videocameras.Thesitewasirrigatedartificiallywithanintensityofmaximal30mm/h.Duringafirstsprinklingperiodof5daysinOctober2008,thesloperemainedstable.However,inMarch2009itfailedafteranirrigationperiodof15hours.

ThefirstexperimentinOctober2008showedthatheavyrainfallisnotalwayssufficienttotriggeramassmovement.Theinitialsaturationofthesoilplaysanimportantroleconcerningtheslopesstability.Alsothehydrogeologicalcharacterofthebedrockshouldbetakenintoaccount.Thesandstoneinthesprinklingareaactedmostlikelyasadrainduetoitslargejoints.Theinitialconditionsforthesecondexperimentinfall2009weredifferentbecausesoilandbedrockweremoresatu-ratedafterrainyperiodsandsnowmelt.Thisismostlikelythereasonfortherapidtriggeringofa~180m2largelandslide.

Basedonfieldandlaboratoryparameters,a2Dfiniteelementflowmodeliscreated.Itshowstherelationshipbetweensur-facewaterinfiltrationandthespatiallyandtemporallyevolutionofporewaterpressuresbeforeandduringtheslopefailure.Thisgivesnewfindingsofthehydraulicconditionsinthesubsurfaceduringthetriggeringofashallowlandslide.Infuturework,themodelledporewaterpressuredistributioncanbecombinedwithmechanicalslopestabilitycalculations.

This studywas carriedout in the frameof theTRAMMProject (TriggeringofRapidMassMovements) financedbyCCES(CompetenceCenterEnvironmentandSustainabilityoftheETHDomain).

Figure1:LocationoftheRüdlingensprinklingexperiment.Noticetheregressiveerosionprocessesinthegulliesandatthesteepborders

oftheRiverRhine(http://www.sh.ch).

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Controls on the form of bars in braided rivers

CastelltortSébastien1&GredigGaudenz1

1ETH-Zürich, Earth Surface Dynamics, Sonneggstrasse 5, 8092 Zürich (sebastien.castelltort@erdw.ethz.ch)

Despitetheconsiderableamountofworkcompletedonthemorphologyofbraidedrivers,thecontrolsontheformofbraidbarswithinchannelsandtheprocessesthatcontributetotheirformationarestillunclear.Moststudieshavefocusedonthecomplexity of braiding and have tried tomeasure and characterize this complexity (see e.g. Egozi and Ashmore, 2008).Throughdifferentapproachesitisshownclearlyinthesestudiesthatthedegreeorintensityofbraidingiscontrolledbytheslope,dischargeandquantityandqualityofthesedimentintransport.Manyattemptshavealsobeenmadeatusingtheseparametersinordertofindthreshold-separatedfieldsofexistenceofthebraidedormeanderingchannelpatterns.Thesandorgravelbarsthatseparatechannelswithinabraidedriverreachhavebeengivenadifferentkindofattention:moststudiesinterestedinbraidbarshaveexploredanddescribedthesedimentaryprocessesactingupontheirformation,theirresultingsedimentaryarchitectureandtheirsedimentology.Thereasonforthisfocusisthatbraidbarsultimatelyfillchannelsandthusrepresentthebulkofthecoarsefillofcontinentalenvironmentsrelatedtobraidedsystemss.l.,potentialreservoirsofcrucialimportancetoresourcegeology.

However,arebraidbarsdifferentinriverswithdifferentslopes,grainsizeordischarge?Nodatahaseverbeencollectedbe-forethatcanallowustoanswerthisquestion.Inthepresentworkwepresentnewdatathatfillinthisgapinknowledge.

TakingadvantageofmethodsdevelopedtostudytheshapeofrivernetworksinmountainrangesatETH-Zürich(Castelltortetal.,2009)andimageanalysismethodsdevelopedformicroscopepetrography(JMicroVision©,UniversityofGeneva),westudythecharacteristicanglebetweenchannelsatmultipleflowconvergencesin10braidedriversworldwide.Weshowthatbarsbecomemoreelongateandnarrowasslopeincreases(Figure1).Thisintuitivelyconsistentresulthasimportantimpli-cations:1)itconfirmsthatthemainprocessesthatshapebraidbarsareerosiveinnature(MurrayandPaola,1994).Abraidedrivercanbeconsideredclosetoasuccessionofrivernetworksincisinganewsurfaceaftereachflood.2)iftheformofbraidbarscanbeinferredfromfossildeposits,thepaleoslopeoftherivercanbededuced.

Slopehoweverisnotanindependentparameterofriverevolution.Itisindeedcontrolledbythecompetitionbetweenwaterdischargeandsedimentfluxandgrainsizewhicharetheonlyindependentvariablesattheupstreamboundaryofariversystem.Ongivenfluvialsuccessions,giventhesedimentgrainsizedistribution,thereconstructionofbraidbarsmorpholo-gyandpaleoslopecanprovideuniqueinformationsonriverpaleo-hydrologyandclimate.

Figure1.Braidbarmeanelongation(equivalentconfluenceangleindegrees)versusriverslope.Thebraidbarsarebroader(largeconflu-

enceangle)onsmallerslopesandmoreelongate(smallconfluenceangle)onhighslopes.

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sREFERENCESCastelltortS.,SimpsonG.&DarrioulatA.(2009)–Slope-controlontheformofriverbasins,TerraNova,inpress.EgoziR.&AshmoreP.(2008)–Definingandmeasuringbraidingintensity.EarthSurfaceProcessesandLandforms,33,2121-

2138.Murray,A.B.&Paola,C.(1994)–Acellularmodelofbraidedstreams,Nature,v.371,54-57.Roduit,N. – JMicroVision: Imageanalysis toolbox formeasuringandquantifyingcomponentsofhigh-definition images.

Version1.2.2.http://www.jmicrovision.com(accessedMay2009).

10.6

Discrete simulation of biogeochemical exchanges in a microbial mat

ChappatteDamien1,VerrecchiaEric2

1Institut de Géologie et Paléontologie, Université de Lausanne, Anthropole, CH-1015 Lausanne, damien.chappatte@unil.ch2Institut de Géologie et Paléontologie, Université de Lausanne, Anthropole, CH-1015 Lausanne, eric.verrecchia@unil.ch

Microbialmatsarecomplexecosystems,whichplayedandstillplayamajorroleintheEarthsystem.Theirbiogeochemicalfunctioningisstillnotcompletelyunderstood.Microbialmatsaredrivenbyseveralguildsofbacteria(withtheirownmeta-bolisms),chemicalsubstances,light,andmanyotherexternalandinternalparameters.Conventionalapproachestocompu-tersimulatesuchageo-ecosystemusenumericalmodels,usuallybasedondifferentialequationsandtheirsolutions.Weproposetoexploreadifferentwaybyusinganothercomputersciencetool,discretesimulation.

Indiscretesimulation,timeandspacearediscretizedintimestepsandcells.Eachcellcontainsthestateofasmallpartofthemat.Timestepsareiteratedoverthecourseofthesimulation,andeachcellstateisupdated.

Inoursimulations,cellscontaininformationaboutchemicalsubstances,chemicalreactions,light,andbacteriacharacteri-zedbytheirmetabolisms.Simulationsgeneratedatasimilartothoseobtainedinanaturalenvironment,suchaschemicalsubstanceconcentrationsorlightintensities.Suchdatacanbeobtainedinanycellatanytimestep,thesamewayanaturalscientistwouldgetmeasurementsinthefieldatdifferentpointsinamatandatdifferenttimesoftheday.Consequently,graphsandprofilescanbeplottedandsimulationresultscomparedtorealmicrobialmatmeasurements.

Preliminaryresultsshowthatthistoolcanmimicthedielcyclesofmainchemicalsubstancesfoundinmicrobialmats(suchasO,S,orC).Thegoalistoextendthemodelcapacityinordertoprecipitatecalciumcarbonate,leadingtothesimulationofstromatolitegrowth.Inthisway,wewillhaveaccesstoavirtuallaboratoryinwhicheasyexperimentscouldberuntocheckhypothesesregardingbiogeochemicalbehaviourofmicrobialmatsduringtheEarth’shistory.

10.7

Reconstruction of past vegetation succession on developping podzols using organic and mineral specific markers

CommentNicolas1,PinardGladys1,AbivenSamuel2,AdatteThierry3,GobatJean-Michel1&VerrecchiaEric3

1Laboratoire Sol & Végétation, Université de Neuchâtel, Emile-Argand 11, CH-2009 Neuchâtel (nicolas.comment@unine.ch)2Soil Science and Biogeography Unit, University of Zurich – Irchel, Winterthurerstr. 190, CH-8057 Zurich3Laboratoire des Biogéosciences, Université de Lausanne, Anthropole, CH-1015 Lausanne

Podzolisationisapedogeneticprocesscaracterisedbydifferentmodificationsoftheorganicmatterandmineralmaterialovertime.Thisprocessoccursunderspecificbioticandabioticconditions.Themajoroneisthepresenceofanacidifyinglitter,whichcouldbefoundundermoorlandorunderconiferouslitter.However,podzolsarealsofoundundermeadows,whichindicatethatthevegetationchangedduringthepodzolisationprocess.

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ces ThestudysiteislocatedinSaint-Luc(VS)between2100and2900metera.s.l.Soilprofilsweredugunderdifferentvegetation

types,coniferforest,moorlandandgrassland.Thisstudyproposestoreconstructpastvegetationandassociatedpodzolisati-onprocessesusingspecificbio-andmineralmarkers.

Weusedligninasbiomarkersofthevegetation,sincethismoleculeisonlyoriginatedfromplants.Also,theligninmoleculesareoftenconsideredasrecalcitrantinthesoilandsothechancetofindtracesofformervegetationislarger.Theligninwasextractedusingthecupricoxideoxidationprocedure.Briefly, thesoil sampleswereextractedusinganalkalinesolutionunderN

2atmosphere.Thesolutionswerecleanedandtheconcentrationof8specificphenolicmonomersforligninwere

measuredbyGC–FID.Thecalculationofratiosallowedustocomparetheactualcompositionofthesoillignintotheligninofdifferentvegetationtypes.

Thepodzolisationprocesswascaracterisedby(1)themobilizationofironand(2)thedestructionandneogenesisofclays.(1)Duringpodzolisation,ironbindsorganicmattertogetherintheformofchelates.Thiscomplexationenablesirontoper-colate throughthesoil.Theeluvialhorizonbecomesdepleted in iron.Toestimate the lossesof iron, twoextractionsoneluvialhorizonsweredone (i) tetraborateof sodiumand (ii) citrate-bicarbonate-dithionite (CBD).Tetraborateextracts theformofironthatischaracteristicforpodzolisationandCBDallformsofironwhicharepresentinsoil(excludingcrystalizedforms).Then,theratio(Fetetraborate/FeCBD)iscalculated.(2)Litterdecomposition,rootsandmicroorganismsreleaseorga-nicacidswhichattackphyllosilicates(micaandchlorite).Thisweatheringleadstotheneogenesisofnewclaymineralfol-lowingthisorder:mica-vermiculitemixedlayers–vermiculite–mica-smectitemixedlayers–kaolinite.BulkrockandclaymineralassemblageswereanalyzedbyX-raydiffraction(ARLX’TRADiffractometer).

Thefirstresultsofironformsshowthepresenceoftwoclassesofeluvialhorizon(Figure1).Theirdistinction’slimitisnear2550ma.s.l.It’sinterestingtounderlinethatthisheightcorrespondsglobalytothehigherlimitthattheforesthadneverreachedinanearbyvalley(Tinneretal.,2003).

Themineralogyofclaysandmobilizedironfromeluvialshorizonsestimatethedegreeofpodzolisationofthedifferentsoils.Theseresultswillbecorrelectedtothelignindatainordertotracethedifferentkindofvegetationthatmighthavebeengrowing there. These results emphasize the role of combined organic andmineralmatters in thepodzolisation processthroughtime.

Figure1:Dendrogramofeluvialhorizonsdistributionaccordingtoeuclidiandistance(Wardagglomeration).Thevariables“altitude”and

“ratio(Fetetraborate/FeCBD)”havebeenusedtoperformcalculations.Thenumberdownbelowisthealtitudeofthestudiedsoil.

REFERENCETinner,W.&Theurillat,J.-P.2003:UppermostLimit,Extent,andFluctuationsoftheTimberlineandTreelineEcoclineintheSwissCentral

AlpsduringthePast11,500Years.Arctic,Antarctic,andAlpineResearch,35,158-169.

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10.8

Etude de la dynamique des éléments traces métalliques en forêt périur-baine (Isle-Adam, Val d’Oise, France):approche écosystémique

EhrhardtFiona1,MateraVirginie2,AdatteThierry3,VerrecchiaEric3

1Laboratoire Sol et Végétation, Université de Neuchâtel, Emile-Argand 11, CH-2009 Neuchâtel (fiona.ehrhardt@unine.ch)2 Institut d’Hydrogéologie et de Géothermie, Université de Neuchâtel, Emile-Argand 11, CH-2009 Neuchâtel3Laboratoire des Biogéosciences, Université de Lausanne, Anthropole, CH-1015 Lausanne

Cetteétudeseconcentresurladistributionetl’originedesélémentstracesmétalliques(ETM)dansuneforêtpéri-urbaineprochedeParis (L’Isle-Adam). Elleviseà intégrerdifférentscompartimentsde l’écosystèmeforestierafindemieuxcom-prendrelesinterrelationsetlesinfluencesréciproques.Ainsi,lelongd’untransect,dixstationsontétésélectionnéesdanslebutd’étudierfonctionnellementlessolsetlesformesd’humusassociées,etdequantifierlesETMprésents.Cecicomplètecertainstravauxdéjàeffectués(Hernandezetal.,2003),etpréciselelienentreETMetphasesporteuses.

Dansunpremiertemps,l’utilisationdesanalysesstatistiquesapermisdepréciserlesprincipauxfacteursdedistribution(Borůvka,2005),etce,dèsledépôtdespolluantsatmosphériquesensurfacejusquedansl’ensembledesprofilsdessolsétu-diés.Lesrésultatsmontrentainsiquel’analysedelalitière (OL)permetdedécelerl’originedeséléments (endistinguantnotammentlesapportsgéogéniquesdesapportsanthropiques)ainsiqueleurmodededépôt.Leshorizonsdefragmentation(OF)permettentensuitelaréorganisationdesélémentsenfonctiondesaffinitéspourlesdifférentesphasesporteusesdusoletlecomportementchimiquedechacun.Enfin,dansleshorizonsOH,qualitédelamatièreorganiqueetdegréd’humificationsemblentdicterladistributiondesETM.

S’agissantdelarépartitionglobaledesETMdansl’ensembledesprofilsdesolétudiés,nousavonsconstatéquelesfacteursdedistributionsontprincipalementliésàdeuxgradientscomplémentaires(fig.1),l’uncoupléàlaprésencedematièreor-ganiquequidiminueaveclaprofondeuretl’autre,inverse,associéàl’augmentationdelaproportiondematièreminérale(notammentlaproportiondephyllosilicates).Nousavonsainsipudémontrer,grâceàuneétudeminéralogique,l’importancedessmectitesdanslamigrationdesETM.

L’étudedufacteurd’enrichissementdesETMpermetdepréciserdavantagelapartdelacontributionanthropiquedecelled’originegéogène(Blaser,2000)etdevisualiserlamigrationdesélémentsanthropiquesàtraversleprofildesol.Ainsileplomb,bienqueréputépeumobile,semblecapabledemigrerjusqu’àdesprofondeursimportantesdanscetyped’écosystème.LafaunedusolcontribueégalementàladynamiquedesETMencréantlesformesd’humusetnousavonsvuquelacompo-sitionfaunistiqueestpropreàchaquegrandtypedeformed’humus.Ellepermetl’intégrationdelaMOdanslessols,con-tribueàsaminéralisationetdoncàlaremiseencirculationdesETMliésàlaMO.LesrésultatsexprimentdesvaleursrelativementélevéespourlePb(jusqu’à130ppmdanslessolset210ppmdansleshori-zonsOH),leCr(jusqu’à342ppmdansleshorizonsOF)etleCd(jusqu’à1.12ppmdansleshorizonsOFetOH),mettantenavantl’importancedeshorizonshumifèresdanslestockageetlaséquestrationdeceséléments.Cesvaleursdépassentlesvaleurslimitesdéfiniesparl’Osol(1998),àsavoir50ppmpourlePb,50ppmpourleCret0.8ppmpourleCd.

Enconclusion,lesrésultatsobtenusmontrentquelefonctionnementmêmedusoldétermineladistributiondesETMselonlesdynamiquesdelaMOetdesphyllosilicatesquiluisontpropres.

REFERENCESBlaser,P.etal.,2000.Criticalexaminationoftraceelementenrichmentsanddepletionsinsoils:As,Cr,Cu,Ni,Pb,andZn

inSwissforestsoils.TheScienceoftheTotalEnvironment249,257-280.Borůvka,L.etal.,2005.Principalcomponentanalysisasatooltoindicatetheoriginofpotentiallytoxicelementsinsoils.

Geoderma128,289-300.Hernandez,L.etal.,2003.HeavymetaldistributioninsomeFrenchforestsoils:evidenceforatmosphericcontamination.

TheScienceoftheTotalEnvironment312,195-219.Osol, 1998.Ordonnance sur les atteintesportées au sol.OFEV, confédérationSuisse; ordonnancedu1er juillet 1998,n°

814.12.

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Fig.1:SchémasynthétiquedelarépartitiondesETM(Pb,Zn,Cu,Cd,Ni,Cr,Mo,As,Co)dansleshorizonsdesol(n=78),paruneACP.VariancesexpliquéessurCP1:58%etCP2:16%.

10.9

Soil porosities as engineered by earthworms microcosm experiment with tomography and shrinkage analysis assessment

FrançoisFüllemann12,RoxaneMilleret2,Y.Capowiez3,Renée-ClaireLeBayon2,Jean-Michel-Gobat2,&PascalBoivin1

1 Laboratoire Sols et Substrat, hepia-Lullier, route de Presinge 150, 1254 Jussy, Genève (fullemann@gmail.com)2 Laboratoire Sol et Végétation, Université de Neuchâtel, rue Emile-Argand 11, CP 158, 2009 Neuchâtel.3 INRA Montfavet

Earthwormsareknowntoplayakeyroleonsoilecologicalprocessessuchasorganicmatterturnover,nutrientcyclingandsoilphysicalpropertiesengineering.Theyareacknowledgedasessentialtosoilfertility.However,theirroleonnumeroussoilphysicalpropertiesisstillpoorlydocumented.Theobjectivesofthepresentstudyweretotesttheeffectoftwoearth-wormecologicalcategories(Nicrodrilus nocturnusasanecic,Alollobophora ictericaasendogeicspecies,andbothasmixedpopu-lation with 80% weight of N nocturnus and 20% of A. icterica) on two different soils. Shrinkage analysis and ComputedTomographywereusedtoassesstheimpactofearthwormsonsoilporositiesandbulkvolume.Thestudywasperformedduring23weeksonmicrocosmsundercontrolledconditions(constanttemperatureandconstantsoilmatrixpotential).ThesoilswereasiltloamLuvisolandaloamyAnthrosol.Inaddition,beforetheintroductionofearthworms,allmicrocosmsweresetattwolevelsofsoilcompactionfurthercalledcompactedanduncompactedsoils.

Theobservedeffectsvariedwiththefactors ‘soil type’, ‘initialsoilbulkdensity’and ‘earthwormspecies’,andwiththeirinteractions. The bulk soil volumewasmodified by earthworms,with decompaction of the compactedmicrocosms andcompactionofthenoncompactedones.Thebulkvolumechangeswerethensplitintowormgalleryporesgenerated,andadditionaleffectonsmallerstructuralporesorplasmapores.Amodelofthechangesinducedby‘anecic’,‘endogeic’and‘mixed’was then formulated.The impactaredifferentaccording to the considered soil volume:bulk soilor soilmatrixwithoutporesduetogalleries,structuralporosityandplasmicporosity,respectively.Roughly,thedecompactioneffectofwormsisduetotheopeningofgalleriesatbulksoilscale,butthematrixiseithercompacted(caseofnotcompactedsoil)orunchanged(caseofcompactedsoil),andthecompactionofthematrixislargerwithendogeicspecies.Themixed-speciestreatmentinducedthesameeffectsasmonospecificonesinmostcases,andtheaneciceffectwasdominant,buttheendo-geiceffectwaseffectiveonmostconsideredsoilvolumes.Somecasesshowedanoppositionbetweenmixedactivitiesandsingletreatments,pointingoutparticularecologicalemergentproperties.

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FloodAlp! Frequency and intensity of extreme floods in the Alps through the Holocene

GlurLukas1,WirthStefanieB.2,AnselmettiFlavioS.1,GilliAdrian2&HaugGeraldH.2

1Eawag, Swiss Federal Institut of Aquatic Science and Technology, CH-8600 Dübendorf (lukas.glur@eawag.ch)2Geological Institute, ETH Zurich, Sonneggstr. 5, 8092 Zürich (stefanie.wirth@erdw.ethz.ch)

FloodscausedbyextremeprecipitationeventsrepresentoneofthemajornaturalhazardsintheAlpinerealm.Newclimatemodelspointtothepossibilitythatfloodfrequencyandintensitiesincreaseasaresultoftheupcomingclimatechanges.Toscalethesepredictedchangesofextremeevents,knowledgeoftheirnaturalvarietyisrequired.

TheFloodAlp!projectaimstoreconstructthefrequencyandintensitiesofHolocenefloodeventsintheAlpsbyusinglakesedimentsasnaturalgeologicarchives,whichactasprehistoricrecordersofextremeevents.Lakebasinsrecordsucheventswithcharacteristicsedimentlayersthatcontrastsharplytotheregularbackgroundsediments.Thehighdischargevalueswithlargeamountsofsuspendedparticlestriggerturbiditicunderflowsthatfocusthedetritalparticlesinthedeepestareasofthebasins.

Atotaloftwelvelakesalonganorth-southtransectcoveringawiderangeinaltitudewillbeinvestigatedduringtheproject.Eachtargetedlakeisfirstinvestigatedbyahigh-resolution(3.5kHz)reflectionseismicsurvey,providinginformationonthesedimentthickness,seismicstratigraphy,sedimentdistributionandidealcoringlocations.Afterthisfirstevaluation,longsedimentcores(max.length16m)aretakeninthedeepestdepressionofthelakebasin.

Preconditionforestablishingthefloodrecordisagoodagemodel,whichisaccomplishedby14Cand137Cs/210Pbdating.Alsocrucialisthedifferentiationbetweenbackgroundsedimentationandeventlayersaswellasbetweenmass-movement-relatedandflood-relatedeventdeposits.Thischaracterisationofthesedimentaryfaciesisachievedbychemical,physicalandmine-ralogicalanalysesofthesedimentmaterial.

Firstresultsfromtwolakes(LakeLedro,I,andHintererSchwendisee,CH)showalreadythepotentialofthisapproach.High-resolutionreflectionseismicprofilesareabletoimagethegeometryofthesedimentfillinganddefinethespatialfocusoffloodlayeraccumulation.Furthermore,overhundredflood-relatedturbiditedepositsineachlakearesharplydistinguisha-blefromthebackgroundsediment.Theagemodelsofthetwosediment-successionsprovidethemeanstoconstructawell-datedchronologyofthesepotentialhazardouseventsthroughouttheHolocene.

10.11

Effects of atmospheric deposition of acid compounds and nitrogen on soil solution in Swiss forests

GrafPannatierElisabeth1,SchmittMaria1,ThimonierAnne1&WaldnerPeter1

1Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, CH-8903 Birmensdorf (elisabeth.pannatier@wsl.ch)

IntheframeworkoftheLong-termForestEcosystemResearchLWF,thechemistryofatmosphericdepositionandsoilsoluti-onhavebeenanalysedfortnightlysince1998orlaterinsevenforestplotsinSwitzerland.Weaimtoassessthesoilresponsetotheinputsofacidcompoundsandnitrogen(N)sincetheymightalterthesoilfunctionsandrepresentpotentialstressfactorsforforestecosystems.Aciddepositionmightacceleratesoilacidification,leadingtotheleachingofnutrientsand/orthemobilizationoftoxicaluminumforsensitiveplants.IncreasedNconcentrationsinthesoilsolutionmayleadtonutrientimbalancesfortreesandchangesinthecompositionofgroundvegetation.Largenitrateleachingbelowtherootzonemightalsothreatenthequalityoftheground-andsurface-water.

Atmosphericdepositionofthemajorelementswasestimatedfromthroughfallandbulkdepositionmeasurementssince1995orlater.Soilsolutionhasbeenmeasuredsince1998orlateratfoursoildepths(belowlitterlayer,15cm,50cm,80cm).Themolarratioofbasenutrientcationstoaluminum(BC/Al)inthesoilsolutionwasdeterminedtoassesssoilacidification.ThisratioisusedasindicatorinmostcriticalloadmodelsinEurope,assumingBC/Alratiossmallerthan1mightcausead-verseeffectontreeroots.Nitrate leachingfluxleavingtherootzonewasestimatedfromsoilsolutionsamplesat80cmdepthusingnitrateconcentrationsandmodelledinfiltrationrates.

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intheAlpsandthehighestloadinSouthernSwitzerland.Totalnitrogendepositionvariedbetween2.4kgha-1a-1intheAlpsto31kgha-1a-1intheSouthernSwitzerland.ThehighacidandnitrogenloadsinsouthernSwitzerlandcomepartlyfromtheemissionsoftheindustrialisedanddenselypopulatedPoBasin.

TheBC/Alratiosinthesoilsolutiondecreasedinmostplotsduringthetwofirstyearsoftheobservationperiod,whichmightbecausedbytheinstallationofthelysimeters.Afterthisperiod,BC/Alhasstabilizedinfiveplots,suggestingthatacidifica-tionhasproceededveryslowlyduringthelast10years.Attwosites,afurtherdecreaseinBC/Alwasobserved,suggestingafasteracidification.

Nitrateleachingrangingfromabout2and13kgNha-1a-1wasobservedatsitessubjectedtomoderatetohightotalNdeposi-tion(>10kgha-1a-1).TheC/Nratioofthesoilorganiclayer,togetherwiththepooloforganiccarboninthesoilandthehu-mustype,playedacriticalrole.

10.12

OSL-based chronology of the postglacial beach plain NE of Lake Neuchâtel on Swiss Plateau: Problems and possible solutions.

HeerAleksandra1,HajdasIrka2,SteffenDamian3,PreusserFrank3&VeitHeinz1

1InstituteofGeography,UniversityofBern,Hallerstrasse12,CH-3012Bern(heer@giub.unibe.ch)2IonBeamPhysics,SwissFederalInstituteofTechnology(ETHZürich),Schafmattstr.20,CH-8093Zürich3InstitutfürGeologiel,UniversitätBern,Baltzerstrasse1+3,CH-3012Bern

Withtheaimofreconstructingthepostglaciallandscapeevolution(~17’000aBPtilltopresence),OSLhasbeenusedtodateeightprofilesfromafossilbeachplaincalledGrossesMoosontheSwissPlateau.Forfourprofilesradiocarbonagesderivedfromunderlyingandintercalatedorganichorizonshavealsobeencalculated.OSLmeasurementswereconductedonquartzsand-sizegrainsapplyingtheSAR-protocolafteridentifyingtheappropriatemeasurementconditionsinaseriesofexperi-ments(WintleandMurray2006).However,werecognisedproblemsduetotheintrinsicpropertiesoftheinvestigatedquartzaswellasduetothechangingenvironmentalconditionsduringtheexpectedburialtime.

Thequartzgrainsaregenerallydim.Hencethemeasurementsof2mmaliquotssufferfromsignificanterrorsduetothesignalintensity(Duller2007,Li2007).Formost2mmaliquotstheerrorsarehigherthen10%.Theconsequenceofacceptingforerrorshigherthen10%leadstoanoverestimationofthetrueage.Thedatingofveryyoungsedimentsalsosuffersfromthelimitationduetothedimsignal.Whenthequartzisdimandoneuses2mmaliquots,therewillbepreferentialselectionofaliquotsthatcontaingrainswithhigherdoses.PossiblecausesforgrainswithhighdosesareradioactivehotspotssuchaszircongrainsorK-feldsparsandthesehavebeenidentifiedinthesesamples.For2mmaliquotstheCW-OSLsignalamountoffastcomponentvariesbetween24%-66%.Thedimsignalisprobablyresponsibleforthoseerrors.Howeverthissignalmaycomefromquartzwithotherproperties.Ontheotherhand,whenusingbiggersizedaliquots(6or8mm)theresultsimpro-vesignificantly:thefastcomponentamountrisesuptomorethen80%oftheentireinitialsignalandtheerrorsstaylowerthen10%.I

nat–D

e-%D

e-error–plotshavebinconstructedtovisualisethiscoherenceandtochecktheindependencyofI

nat

and%De–errorasstatisticalvariablesinfluencingtheD

edetermination.ForselectedsamplesOSLsignalpropertiesand

resultingconsequencesfordatingwillbepresented.Alsothethicknessoftheoverlyingdepositchangedduringtheburialtime.EspeciallyforprofileISL6the14C-datahelpedindeterminingthedurationofthesucceedingdeposition.Otherwisetheageofthebasicpalaeochannelwouldhavebeenoverestimated.Groundwateroscillationshavebeenrecognizedwhilerecor-dinghydromorphicsoilfeatures.Thereforethereliabilityofthecurrentlyrecordedwatercontentforthewholeexpectedburialtimehasbeencheckedforeachsampleseparately.Nevertheless,consideringthoseproblemsareliableandconsistentchronologyforGrossesMoos,applyingOSL–and14C–data,hasbeendeveloped.

REFERENCESDuller,G.A.T.,(2007),Assessingtheerroronequivalentdoseestimatesderivedfromsinglealiquotregenerativedosemeasur

ements.Ancient,TL25:15-24.Li,B.,(2007),AnoteonestimatingtheerrorwhensubtractingbackgroundcountsfromweakOSLsignals.AncientTL25/1,9-

14.Wintle,A.G.,Murray,A.S.(2006).Areviewofquartzopticallystimulatedluminescencecharacteristicsandtheirrelevance

insingle-aliquotregenerationdatingprotocols.Rad.Measurements41,369-391.

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Is the mineral phase responsible for stabilizing lignin in soils?

HeimAlexander1,HofmannAnett1,MiltnerAnja2,ChristensenBentT.3&SchmidtMichaelW.I.1

1 Department of Geography, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (alexander.heim@geo.uzh.ch)2 Department Environmental Biotechnology, Helmholtz Centre for Environmental Research - UFZ, Permoserstraße 15, D-04318 Leipzig3 Department of Agroecology and Environment, Faculty of Agricultural Sciences, University of Aarhus, DK-8830 Tjele

Ligninisthesecondmostabundantbiopolymerinhigherplants.Itsfateinthesoilisstilllargelyobscure.Ononehand,manylitterbagstudiespointtoaselectiveenrichmentofligninduringtheearlyphaseoflitterdecomposition.Ontheotherhand,compoundspecificisotopeanalysisoflignin-specificbiomarkershasshownthattheaverageturnovertimeoflignininsoilsissimilarorfasterthanthatofbulksoilorganiccarbon.Massbalancescombiningannualinput,soilligninstocksandturnoverratesinferredfromisotopedata,suggesttheexistenceofatleasttwokineticpools,oneofwhichdisappearsveryfast.Forbulksoilorganiccarbon(SOC),interactionsoforganicmatterwiththemineralphaseinsoilseemtobeanimportantsta-bilizationmechanism.However,verylittledataareavailableonthetypeofcompoundsthatinteractwiththemineralphase.

Ligninmonomersarebiomarkersofrelatively freshplant inputs.Theaimof thisstudy is totracethesebiomarkers intodifferentsoil fractions,answeringthefollowingquestions: (I)Whichsoil fractions (size,density)containmost lignin? (II)Doesthestabilityof ligninvarybetweenthese fractions? (III)Candifferences in lignincontentbetweensoil fractionsbeexplainedbypropertiesofthemineralphase(surfacearea,typeofminerals)?

Thestudywasconductedwitharablesoilfromalong-termexperimentthathadbeennaturally13C-labelledby18yearsofmaizecropping.Weidentifiedoldligninderivingfromthetimebeforemaizecroppingbycompound-specificisotopeanaly-sisoflignin-derivedphenolicbiomarkersandcompareditsdistributionwithinthesoiltotheinitialdistributioninanarchi-vedsoilsample.Alargeproportionofligninwasfoundinthecoarseheavyfraction,suggestinginclusionintomacroaggregates.However,iso-topedataclearlyindicatedthatlignininthisfractionwaslessstableinthelong-termthanlignininlightfractionsorinsilt-sizeaggregates.Thelignin/SOCratioofthelattertwofractionsindicatesthattheycontainlessdecomposedorganicmatter.

Wesuggest that the followingmechanismsmaycontrol stabilityof lignin inarablesoils: (1)Some lignin-containingcellstructures(e.g.thickcellwalls)seemtobeindeedrecalcitrantenoughtopersistfordecadesevenunderintensivecropping.Duetointensivecroppingbeforetheisotopiclabelingstarted,thelightfractionsarealreadyenrichedintheserecalcitrantstructures,andthereforeshowverylittledegradationduringtheobservationperiod.(2)Stablesilt-sizeaggregatesmaypre-servesmallfragmentsofrelativelyundecomposedplantresidues.(3)Macroaggregates,bycontrast,turnovermorerapidly,sothatinclusionintomacroaggregatesdoesnotstabilizeligninaslongastheothermechanisms.

10.14

Pyrogenic carbon solubility in the soils: quantitative and qualitative approaches

HengartnerPascal1,AbivenSamuel1

1Soil Science and Biogeography, Department of Geography, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich (Samuel.abiven@geo.uzh.ch)

Thepyrogeniccarbon(PyC)correspondstothebiomassresiduesaftertheirincompletecombustion,mainlybywildfires.Untilrecentstudies,thisparticularkindofsoilorganicmatterwasconsideredaspassive,recalcitrantandsostableinthesoils.

Recently,differentauthorshighlighted significantbioticdegradation (BaldockandSmernik,2002;Hammeret al., 2004)and/orabioticdegradation(forexampleSmithandChughtai,1996)ofthesecompounds.Moreover,specificPyCbiomarkerswerefoundinsurfaceandmarinewatersandinsediments(Hockadayetal.,2006).ThesetwofindingsmightindicatethatafractionofthisPyCistranslocatedthoughthesoil.

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ces However,thequantityandthecharacteristicsofthisPyCfractionaswellasthemechanismsoftheirtransportsintheenvi-

ronmentremainlargelyunknown.Inthisstudy,weproposetoestimatethequantityandthefeaturesofthesolubleandcolloidalfractionofPyC.

ThePyCusedinthisstudyistheinternationalstandardasdefinedbytheblackcarbonsteeringcommittee:CastaneasativaMill.Wood,pryrolisedat450°Cduring16hunderaN

2stream.Thecharwasthengrounded(<1mm).

Thewater-extractiblefractionwasfirstestimatedinabatchexperimentinthelab.Thecharwasshakeindeionisedwaterattherateof160gChar.l-1andthefractionsbelow0.45µm(solublefraction)andbelow5µm(colloidalfraction)werecollectedby filtration.We repeated this batch designwith 10 years old char pieces that we collected from a fire experiment inTessin.Then,weappliedthestandardchartoacambisolinthefield(LaegernHills,Aargau,CH)andwecollectedregularlythesoilsolutionwithsuctionplates.

ThePyCquantityandcharacteristicswereanalysedusingmassbalance,CandNcontentandtheBenzenePolyCarboxylicAcidsmethod(BPCA,Browdowski,2005).Thismethodconsistsinanaciddigestionofaromaticcompounds,releasingpoly-carboxylicacidswhichareconsideredasspecificPyCbiomarkers.Inthisstudy,weadaptedthemethodtosmallpyrogeniccompounds.Inthebatchexperiment,thesolublefractionrepresented1permiloftheinitialcharmass(Fig.1).Thefractiononlycon-tained38%C(comparedto66%fortheinitialchar)and0.66%N(comparedto0.07%intheinitialchar),indicatingthatthesolublefractioncontainsmuchothercompoundsthanaromaticPyCmoieties.ThespecificPyCbiomarkerswereonlyrepresenting1%ofthedissolvedCcontent.

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Logarithmicscale.

REFERENCESBaldock,J.A.,andR. J.Smernik.2002:ChemicalcompositionandbioavailabilityofthermallyalteredPinusresinosa (Red

pine)wood.OrganicGeochemistry,33,1093-1109.Brodowski, S. 2005.Origin, function, and reactivityofblack carbon in thearable soil environment. PhDThesis,Bonner

BodenkundlicheAbhandlungen,pp.183.Hamer, U., B.Marschner, S. Brodowski, andW. Amelung. 2004. Interactive priming of black carbon and glucose

mineralization,OrganicGeochemistry,35,823-830.Hammes,K.,Smernik,R.J.,Skjemstad, J.O.,Vogt,U.F.,Schmidt,M.W.I.2006:Synthesisandcharacterisationof laboratory-

charred grass straw(Oryza sativa) and chestnutwood(Castanea sativa) as referencematerials for black carbonquantification.OrganicGeochemistry,37,1629-1633.

Hockaday,W.C.,A.M.Grannas,S.Kim,andP.G.Hatcher,2006:Directmolecularevidenceforthedegradationandmobilityof black carbon in soils fromultrahigh-resolutionmass spectral analysis of dissolved organicmatter froma fire-impactedforestsoil,OrganicGeochemistry,37,501–510.

Smith,D.M.,&A.R.Chughtai. 1996:Reactionkinetics of ozone at low concentrationswithn-hexane soot, Journal ofGeophysicalRessources,101,19,607–19,620.

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Quantifying rates of surface denudation at the eastern Altiplano margin, La Paz region, Bolivia

K.Hippe1,F.Kober2,G.Zeilinger3,S.Ivy-Ochs4,P.W.Kubik4,C.Schlüchter5&R.Wieler1

1 Isotope Geology and Mineral Resources, ETH Zürich, CH-8092 Zürich, Switzerland (hippe@erdw.ethz.ch)2 Institute of Geology, ETH Zürich, CH-8092 Zürich, Switzerland3 Institute of Geology, Univ. Potsdam, D-14476 Golm, Germany4 Laboratory of Ion Beam Physics, ETH Zürich, CH-8093 Zürich, Switzerland5 Institute of Geological Sciences, University of Bern, CH-3012 Bern, Switzerland

TheBolivianAltiplano isa large, flatplateau framedby thehighpeaksof theWesternandEasternCordillera.Along itseasternmargintheRioLaPazhascutdeeplyacrosstheCordilleraforminganeastward-drainingriversystemthatstandsinsharp morphological contrast to the internally drained Altiplano. Landscape morphology, relief and surface processeschangefundamentallyacrossthedrainagedivide.AfeedbackmechanismbetweenerosionalunloadingbyfocussedincisionandflexuralreboundhasbeenproposedfortheRioLaPazdrainagesystem(Zeilinger&Schlunegger2007),buttheeffectofcrustalbendingontheadjacentAltiplanohasnotyetbeenevaluated.WhiledenudationratesareknownfortheRioLaPazsystem(Zeilingeretal.2009)andtheEasternCordillera(Safranetal.2005),wehavequantifiedratesofdenudationontheAltiplanoside.ForcatchmentsborderingtheRioLaPazdrainagedividewehavedeterminedcatchmentwidedenudationratesbasedoncosmogenic10Beinriversediments.Forallcatchmentsthelandscapeisflatwithsmoothhillslopes;precipita-tionislowwithastronginterannualvariability.

CosmogenicallydetermineddenudationratesintheRioLaPazsystemare0.1-0.6mm/yr(Zeilingeretal.2009).PreliminarydenudationratesfortheAltiplanoareonetotwoordersofmagnitudelowerbetween0.002and0.029mm/yr,withaninte-grationtimeof24-230ky.Thisisinagreementwithmodernsedimentyieldrates(Guyotetal.1992)althoughtheyintegrateoveronlyonetofiveyears.FortheAltiplano,denudationratesshownoclearcorrelationwithmorphometriccatchmentparameters,butratherseemtobeinfluencedbylithology(i.a.glacialdeposits)andpossiblyalsoanthropogenicprocesses.

REFERENCESGuyot, J.L.,Wasson, J.G.,Quintanilla, J.&Calle,H.1992:Dissolvedmatterandsuspendedsediment loads insome inflow

riversandintheRioDesaguadero.In:LakeTiticaca(Ed.byDejoux,C.&Iltis,A.),113-119.Safran,E.B.,Biermann,P.R.,Aalto,R.,Dunne,T.,Whipple,K.X.&Caffee,M.2005:Erosionratesdrivenbychannelnetwork

incisionintheBolivianAndes.EarthSurf.Process.Landforms30,1007-1024.Zeilinger,G.,Kober,F.,Strecker,M.,Ivy-Ochs,S.,Kubik,P.W.&Hippe,K.2009:ErosionratesintheRioLaPazdrainagebasin:

evidenceforspatiallyandtemporallyvariableerosionprocesses.Geophys.Res.Abstracts,EGUGeneralAssembly2009.Zeilinger,G.&Schlunegger, F. 2007: Possible flexural accomodationon the easternedgeof theAltiplano in relation to

focussederosionintheRioLaPazdrainagesystem.TerraNova19,373-380.

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The shape versus the processes of a landform – the Hörnli region, NE-Switzerland

Kober,F.1,Abbühl,L.2,Dürst,M.2,Ivy-Ochs,S.3,Schlunegger,F.2,Kubik,P.W.4

1Geological Institute, ETH Zürich, CH-8092 Zürich (kober@erdw.ethz.ch)2 University of Bern, Baltzerstrasse 1+3, CH-3012 Bern3Ion Beam Physics, Particle Physics, ETH Zürich, CH-8093 Zürich and Department of Geography, University of Zürich, CH-8057 Zürich4Ion Beam Physics, Particle Physics, ETH Zürich, CH-8093 Zürich

AlthoughthelandscapeoftheHörnliregioninNE-Switzerlandwould,atfirstglance,implythatlandscapeprocessesandprocessratesmustbedifferentbetweenthefluviallyandglaciallyoverprintedlandformparts–thereisnostrongevidenceforthisargumentingeomorphicparametersandspatiallyaveragedcatchmentwidedenudationratesobtainedwithcosmo-genic 10Be.While glacially overprinted catchments tend tohave lower average slopes andare at lowermeanelevations,otherparametersfailtoshowcorrelations.Slope-areaplotssuggestpartialrejuvenationforglacialoverprintedcatchments,i.e.,incisionintoaccumulationplanesinthelowerrivercourses.Thisisalsoinaccordancewithobservedknickpointswhicharebeyondthecommonlylithologicallycontrolledchannelsteps(Nagelfluhbanks)thatareobservedeverywhere.Spatiallyaveragedcatchmentwidedenudationratesvarybetween30-2000mm/kywithatendencytowardslowervaluesincatchmentswithglacialoverprint,thoughnotalways.

Itissuggestedthatglaciallyoverprintedcatchmentswithsmoothertopographiesandaccumulatedglacialdepositsintheirlowerreachesprotectthelandscapeagainstfastererosionrates.Anotheroptionwouldbethatglaciallysourcedsedimentsofthecatchmentwithrelativelyhighercosmogenicnuclideconcentrationscontrolthelowerdenudationrates.Incontrast,thefluvialcatchments,withstepperslopesandexposedathigherelevationsarecontrolledbymoreactiveprocesses,suchasshallowlandsliding,rockfalls,debrisflowsandlittlesoildevelopmentwouldpromoteshorterresidencetimeinthecatch-ment,hencehigherdenudationrates.

Assuchitissuggested,thattheremnantsoftheglacialoverprinting,i.e.,sculpturinganddeposition.

10.17

Earthworm, mycorrhiza and root interactions: effects on soil phosphorus nutrient status and soil structureKohler-MilleretRoxane1,LeBayonClaire1,BoivinPascal2&GobatJean-Michel1

1Laboratory Soil & Vegetation, Institute of Biology, Emile-Argand 11, CH-2009 Neuchâtel (Roxane.Milleret@unine.ch) 2Laboratory of Soils and Substrates, HEPIA, Route de Pressinge 150, CH-1254 Jussy Bioticinteractionsinsoilsareknowntoinfluencethebelowgroundandabovegroundsystembyaffectingsoilfertility,i.e.itsnutrientstatusandsoilstructure.Earthworms,arbuscularmycorrhizafungi (AMF)androotsareespeciallyimportantcomponentsofthebelowgroundsystem.WhileAMF-plantsymbiosisisessentialforplantnutrition,theyalsomodifysoilstructureinmechanicalandchemicalways(soilparticlesenmeshmentintobiggeraggregatesandglomalinsecretionforAMF).Earthworms,asecosystemengineers,areknowntoinfluencesoilpropertiesandplantproduction(soilstructureandporositymodificationbyburial and feeding-castingactivities, formationof theorgano-mineral complex,microorganismdispersionoringestion).However,littleisknownabouttheeffectsofearthwormsandAMFonplantgrowthorsoilchemicalandphysicalproperties.Anexperimentalapproachwasthereforedesignedinordertoassessseparatelyorincombinationthe effects of earthworms (Allolobophora chlorotica, Savigny),AMF (Glomus intraradices, SchenkandSmith), andplant roots(Allium porrum,L.)oni)soilstructure,ii)availabilityofnutrients(mainlyphosphorus,P)inthebulksoilaswellasinbothrhizosphereanddrilosphere.

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sTheresultspointoutthatplantrootsimprovedsoilstabilityatthelevelofmacroaggregates(>250µm)anddecreasedthebulksoildensity(asrevealedbyshrinkageanalysis),whereasearthwormsdecreasedsoilstabilityandthebulksoilvolume.AMFhadnoeffectonsoilstructurestabilitybutincreasedPtransferfromthesoiltotheplantandconsequentlyplantbio-mass.EarthwormhadnodirectinfluenceonPuptake,butdrilospheresoilcontainedahigheramountofavailableforms.

ThisstudyshowsthatunderPlimitation,AMFenhanceplantgrowthviaavailablephosphorousacquisition.Inourexperi-ment,earthwormshavenodirecteffectonplantgrowthbutdrilospheresoilmayserveasanutrientpoolthatcanbelatermobilized.Thisexperimenthighlightstheimportanceofaholisticapproachmeasuringphysical,chemicalandbiologicalsoilparameterswhenstudyingsoilorganisminteractionsandtheirinfluenceonplantperformance.

10.18

Entwicklung und Anwendung einer Grobscreening-Methode zur Untersuchung des Abbauzustandes von Moorböden am Beispiel des Lobsigensees

MatileLuzius,AchermannMarco&KrebsRolf

ZHAW, Institut Umwelt und Natürliche Ressourcen, Grüntal, CH- 8820 Wädenswil (luzius.matile@zhaw.ch)

AmUferdesLobsigensees(BE)befindetsichineinemehemaligenNiedermoordieFundstelleeinerneolithischenSiedlung.SeitdasMoorimZusammenhangmitderlandwirtschaftlichenNutzungentwässertwird,findetderTorfabbaustatt.VomAbbau organischer Substanz ist dabei auch ein wesentlicher Teil der archäologischen Fundstelle betroffen. So hat einVergleichderGrabungen von1953und2005gezeigt, dass der Erhaltungsgradder archäologischen Funde sehr stark ab-nahm.

DadietorfabbauendenSchrumpfungs-undMineralisationsprozessediephysikalischenEigenschaftendesBodensverändern,wurdeuntersucht,obsichdurchdieMessungdesEindringwiderstandesgrobeAussagenüberdenAbbauzustanddesorga-nischenBodensunddamitauchderFundstellemachenlassen.UmnebendemAbbauzustandauchdieAbbaurateabzuschät-zen,wurdenVerrottungsversuchemitBaumwolltücherndurchgeführt.

Die mit einem dynamischen Rammpenetrometer (PANDA-Sonde) gemessenen Eindringwiderstände ergaben eine guteKorrelationmitbodenphysikalischenParameternwiederLagerungsdichte,mitdemGehaltorganischerSubstanzundbestä-tigtendenBefundderProfilansprache.

DurchdieMessungdesEindringwiderstandeskönnensomitdichtere(mineralische/antorfige)undlockerereSchichten(Torf)imBodenprofil lokalisiertundinZusammenhangzumAbbauzustandamuntersuchtenStandortgebrachtwerden.DieseeinfacheMethodewürdeeinegrobeÜbersichtüberdasStadiumderMoorsackungder jeweiligenorganischenBöden imTiefenprofil erlauben und damit Rückschlüsse auf den Zustand der betroffenen Fundstellen ermöglichen. DasScreeningverfahrenwäredamiteineeffizienteMethodezurPriorisierunggefährdeterFundstellen.

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INITIAL STAGES OF SOIL AND CLAY MINERALS FORMATION IN THE MORTERATSCH PROGLACIAL AREA (UPPER ENGADINE, SWITZERLAND)

ChristianMavris11,MarkusEgli1,MichaelPlötze2,JoelBlum3,WilfredHaeberli1

1Department of Geography, University of Zurich, Zurich, 8057, Switzerland 1(christian.mavris@geo.uzh.ch)2ETH Zurich, Institute for Geotechnical Engineering, Zurich, 8093, Switzerland3Dept. of Geological Sciences, University of Michigan, Ann Arbor, MI 48109, USA

InvestigationsinAlpinesoilsindicatethatmineralweatheringismuchfasterin‘young’soils(<1000yr)thanin‘old’soils(~10000yr).However,littleisknownabouttheinitialstagesofweatheringandsoilformation,i.e.duringthefirstdecadesofsoilgenesis.Inthisstudyweinvestigatedrock-formingmineralsweatheringatveryearlystagesofsoilformation.DuetothecontinuousretreatoftheMorteratschglacier(UpperEngadine,SwissAlps),theproglacialareaoffersafulltimesequencefrom0to150yroldsurfaces.Alowslopeandtheabsenceofglacierwhichmighthaveinterruptedsoilformationprocesses,contributedtothechoiceoftheMorteratschproglacialvalleyforthiscasestudy.Theareaiswelldocumentedregardingvegetationandsoils.ThetectonicunitistheBernina-crystalline,whichismainlyconstitutedofgranitoidrocks.Consequently,theglacialtillhasanacidiccharacter.Mineralogicalmeasurementswerecarriedoutonthebulksoilfraction(<2mm)usingXRDandDRIFTforqualitativeandquantitativephaseanalysis.Inaddition,chemicalanalysesofthestreamwaterfromthemainchanneland,tributariesandofrainwaterwereperformedwithaspecialfocusonCa/SrandSrisotoperatios(87Sr/86Sr).Furthermore, the accumulation of organicmatterwithin the time sequence and physical soil propertieswere assessed.Decreasinggrainsizewithtimeshowsactivephysicalweatheringprocesses.Soilorganicmatterhasbeenaccumulateddur-ing150yratveryhighrates.Specialemphasishasbeengiventochemicalweatheringandtotheformationandtransforma-tionmechanismsofminerals.Of special interestwerebiotite, chlorite, epidote,plagioclase and calcite. Biotitehasbeencontinuouslytransformedintoillite-likecomponents.Within150years,theconcentrationofepidotesignificantlydecreased.ThehighCa/Sraswellas87Sr/86SrratiosinthestreamandspringwatersconfirmedthatCabearingmineralsareweatheringandtransformingatveryhighratesintheproglacialarea.Alsoincryic,ice-freeenvironments,chemicalweatheringratesarehighleadingtotheformationandtransformationofminerals.Disseminatedcalciteingranitoidrocks,notconfinedtosedimentarycarbonaterocks,alsoplaysaroleinsubglacialenvironments.Itis,however,notknownforhowlongsuchaninfluence is significantandmeasurable.ThehighCa/NaandCa/Srratio inthestreamandtributarywatersshowedthatcalcitecontributestothesupplyofsolubleCa,althoughtheionactivityproductcalculationsclearlydemonstratedthatthewaterswereundersaturatedwithrespecttothismineral.

Fig.1.LocationoftheMorteratschproglacialarea (Engadine,SESwitzerland).M= investigationarea (seeFig.2),A=proglacialarea,B=

Morteratschglacier.

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sREFERENCESBlumJ.D.,KlaueA.,NezatC.A.,DriscollC.T.,JohnsonC.E.,SiccamaT.G.,EagarC.,FaheyT.j.,LikensG.E.2002:Mycorrhizal

weatheringofapatiteasanimportantcalciumsourceinbase-poorforestecosystems.Nature,417,729-731Büchi H. 1994: Der variskische Magmatismus in der östlichen Bernina (Graubünden, Schweiz). Schweizerische

MineralogischeundPetrographischeMitteilungen,74,359-371BurgaC.1999:VegetationdevelopmentontheglacierforefieldMorteratsch(Switzerland).AppliedVegetationScience,2,17-24EgliM.,MirabellaA.,FitzeP.2003:FormationratesofsmectitesderivedfromtwoHolocenechronosequencesintheSwiss

Alps.Geoderma,117,81-98MavrisC.,EgliM.,PlötzeM.,BlumJ.D.,MirabellaA.,GiaccaiD.,HaeberliW.:Initialstagesofweatheringanssoilformation

intheMorteratschproglacialarea(UpperEngadine,Switzerland).Geoderma(submitted)

10.20

Regeneration of mechanically loaded soils under skid lanes by plantation of Alnus glutinosa

MeyerChristine1,LüscherPeter1,SchulinRainer2

1 Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, CH-8903 Birmensdorf (christine.meyer@wsl.ch)2Institute of Terrestrial Ecosystems (ITES), Universitätstrasse 22, CH-8092 Zürich

Afterstorm"Lothar"in1999serioussoildamagesresultedfromclearanceworkswithheavytimbermachineryinmanySwissforests.Inordertoinvestigatehowtheregenerationofcompactedsoilcouldbeenhanced,blackalder(Alnus glutinosa)seed-lingsandwillows(Fig.1)wereplantedin2003intracksofexperimentalskidlanesatthreeselectedforestsitesaffectedbystorm“Lothar”(Habsburg,MessenandBrüttelen).Asanadditionaltreatment,compostwasaddedtosomeoftheplantingsites.

This yearwe started to investigate rootdevelopmentand regenerationof soil structureat theHabsburg site, comparingplantedplotswithandwithoutcompostapplicationwithstockedreferencesites.Nexttoselectedtreesweexcavatedaseriesofsoilprofiles(0.8mdepth,1.5mwidth),thefirstat0.6mdistancetothestem,thesecondat40cmdistanceandthethirdat20cmdistance,andthelastdirectlyatthestembase.Oneachprofile,werecordedthenumbersoffineandmainroots,soilaggregatestructureandhydromorphicsoilfeatures.Furthermore,wetooksoilsampleswithcylinders(1000ccand100cc)foranalysisofbulkdensity,precompactionstress,soilwatercontentandairconductance.

Themorphologicalevidenceindicatedthatsoilstructurehadconsiderablydevelopedoverthe6yearsafterthealderswereplanted.Thealdersplantedincompactedsoilhaddevelopedrootsextendingdownto80cmdepthandmore,butalsoshow-inguntypicalmorphologicalfeaturessuchasflattenedroots.Soilaggregationwasenhancedinpresenceoftrees,andsoilhydromorphyreducedincomparisontocontrolplotswherenotreeshadbeenplanted.Intreatmentswithcompostapplica-tionthenumbersofrootsandtheirdryweightswerehighestandsoilaggregationwasenhancedmostdistinctly.

Nextstepswillbetheanalysisofsoilphysical,mechanicalandchemicalparameters.Incombinationwithbiologicalparam-eterswewillusethisinformationtoidentifythegoverningprocessesandlimitingfactorsofsoilstructureregeneration,toevaluatetheefficiencyoftheplantationandcomposttreatmentsandtoderiveestimatesforthetimerequiredforfullre-covery.

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Figure1.SchematicillustrationoftheexperimentaldesignatthestudysiteHabsburg(Kt.Aargau).

Photograph1.Blackalders(left)andwillows(right)plantedinthetracksofaskidlane.

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Characterization of biochar and their impact on soil fertility

BarbaraPichler1,Hans-PeterSchmidt2,PascalBoivin3&SamuelAbiven1

1Geographisches Institut Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich(barbara.pichler@access.uzh.ch, samuel.abiven@geo.uzh.ch)2Delinat-Institut, Ancienne Eglise 9, CH-1974 Arbaz (schmidt@delinat-institut.org)3Laboratoire sols et substrats, Haute école du paysage, d’ingénierie et d’architecture de Genève, Rte de Presinge 150, CH-1254 Jussy (pascal.boivin@hesge.ch)

Biocharapplicationtothesoilhasbeenproposedrecentlyasatooltoimprovesoilfertilityaswellastomitigateclimatechanges.Biocharisproducedbythecombustionofbiomassunderoxygenlimitedconditions.Theproductionofbiocharaswellastheirusagefollowsthreemainaims:

• Thegasproducedduringthecombustioncanbeusedforenergy(Syngas).• Thebiocharwilldecomposeveryslowlyintothesoilandsomightstabilisecarbononthelongterm.• AccordingtostudiesinAmazonianforest,thebiocharmightalsoimprovesoilfertility(nutrientsandwaterretention).

Inthisstudy,weproposetoinvestigatetheeffectofbiocharonwaterretention.

Duetoitporousstructure,thebiocharhasalargespecificsurfaceareaandmightenhanceforexamplewaterretention,soilaerationandtheadsorptionofnutrientsandpesticides,thuslimitingtheleachingintothegroundwater.

InMarch2008DelinatAGstartedafieldstudyonSOCdepletedvineyardsoilsinValais(CH).10tbiocharperhectarhasbeenincorporatedtogetherwithcompostbetweenthegraperowstoasoildepthof10cm.Thecomposthasbeenappliedwith theaimtoactivate thebiocharwithorganicmatter.Theapplicationofbiocharandcompostwasperformedtogetherwiththesowingoflegumes,inordertopreventerosionandserveasaN-source.Directlyunderthegraperowsbiocharhasjustbeenappliedsuperficially.

Becauseofthepoorlyweathered,shallowsoils,disturbedsoilsampleshasbeentakenonlyfromtheupper20cmofthere-searchpatchmentionedaboveaswellasfromfurtherreferencepatches,including:

• Barevineyardsoilwithoutadditionofbiocharandcompostandwithoutcoverageoflegumes.• Vineyardsoilmixedwithcompostandcoveredwithlegumes.

Largerpiecesofbiocharparticles,whichhavebeenfoundunderthevineplantsontothesoilsurfacealsohavebeencollectedandanalysed.Thesoilsofthedifferentpatchesweresampledatthesamealtitude.

Thewaterretentioninsoilwasmeasuredondisturbedsamplesofthefinefraction,followingtheprocedureofBoivinetal.,2009:Thedriedsoilsamplesweresaturatedtoawaterpotentialof-10hPa.Thesaturatedvolumewasmeasuredusingtheplasticbagmethod.Thesampleswerethendriedinashrinkageapparatusandtheirvolumewasmeasuredagain.Attheendashrinkagecurveofthefineearthcouldbecalculatedtoidentifythepore-dependentwater-storagecapacityofthesoil.Thebiochar(pyrogeniccarbon)contentwasestimatedusingtheBPCAmethod(Brodowskietal.,2005).Thismethodconsistsinanacidoxidationanddeterminationofbenzenepolycarboxylicacidsbychromatography.WealsodeterminedchangesinsoilorganicmatterqualityusingDiffuseReflectanceInfraredFourierTransformationspectrometry.Todeterminethereac-tivesurfacearea,BETspecificsurfaceareawasmeasuredusingagasabsorber.

FirstresultsofthefieldstudywillbepresentedontheSwissGeoscienceMeeting2009.

REFERENCESBoivin, P., Schäffer,B.&Sturny,W.2009:Quantification the relationshipbetween soil organic carbonand soilphysical

propertiesusingshrinkagemodelling,EuropeanJournalofSoilScience,60,265-275.Brodowski,S.,Rodionov,A.,Haumaier,L.,Glaser,B.&Amelung,W.2005:Revisedblackcarbonassessmentusingbenzene

polycarboxylicacids,OrganicGeochemistry,36,1299-1310.

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Rock-Eval Pyrolysis to determine stable organic Matter in irrigated sandy Soils from Palm Orchards

PrudatBrice1,AdatteThierry2,HassounaMohammad2,GobatJean-Michel1,VerrecchiaEric2

1Laboratoire Sol & Végétation, Université de Neuchâtel, Rue Emile-Argand 11, CH-2009 Neuchâtel (brice.prudat@unine.ch)2Laboratoire des Biogéosciences, Université de Lausanne, Anthropole, CH-1015 Lausanne

OveruseofwaterresourcesisoneofthemostimportantproblemsinsouthTunisia.Inthisarea,palmorchardshavethehighestwaterconsumption.Likeinmostsoils,soilorganicmatter(SOM)inthisirrigatedagro-systemhasanimportantroleinwaterefficiency,soilfertilityandcarbonstorage.Consequently,understandingthewayinwhichorganicmatter(OM)isintegratedinsandysoilscouldbeanapproachtopromotesustainableagriculture.TheaimofthisstudyistocharacterizestableSOMpoolsinsandysoils.Palmorchardsconstituteapertinentexperimentalexamplebecausecultivatorsincorporateorganicmaterials–mainlymanure–intothesoileveryfewyears.Therefore,stu-dyingSOMincultivatedareasofdifferentagesisinterestingtoestimatethestableOMpoolspresentinthesesaltyirrigatedsandysoils.Surfacelayersamples(0-20cm)aresievedintodifferentaggregatefractionsinordertoanalyseOM.Then,SOMisextractedfromallaggregatefractionsaswellasbulksoil,usingadoubleextractionprocedure-using0.1MNaOHbeforeandaftertreatmentwith0.1MHCl-followedbyanextractionontheresidualfractionwithasolutionofDMSO/H

2SO

4.Finally,diffe-

rent analytical techniquesareused to characterize (i) chemical extracts (FourierTransform InfraRed spectroscopy (FTIR),Rock-Evalpyrolysis(RE),C/Nratio),(ii)theaggregatefractions(REpyrolysis,C/Nratio)and(iii)thebulksoil(REpyrolysis,C/Nratio).CharacteristicsofpeaksobtainedusingREpyrolysis,coupledwithFTIRspectrawillgive informationonthestructureoforganicmoleculespresentinthesoils.TheresultsobtainedcouldhelptounderstandtheintegrationofOMinsandysoils.Understanding these processes would help to optimize the organic amendment quantities, qualities, and frequencies.Therefore,itwouldpromoteanincreaseinthefarmers’incomesandthereductionofwaterlossesinpalmorchards.

10.23

Morphology and recent history of the Rhone River Delta in Lake Geneva (Switzerland and France)

SastreVincent1,LoizeauJean-Luc1,GreinertJens2,3,NaudtsLieven2,ArpagausPhilippe1,AnselmettiFlavio4&WildiWalter1

1 Institut F.-A. Forel, Université de Genève, 10, route de Suisse, CP 146, CH-1290 Versoix, Switzerland1 . Corresponding author: walter.wildi@unige.ch2 Renard Centre of Marine Geology, Department of Geology and Soil Science Ghent University, Krijgslaan 281 s.8 B-9000 Gent, Belgium3 New affiliation: Royal Netherlands Institute for Sea Research (NIOZ), P.O. Box 59, 1790 AB, Den Burg (Texel), The Netherlands4 Swiss Federal Institute of Aquatic Science & Technology (Eawag), Department of Surface Waters, Sedimentology Group, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland

ThecurrenttopographicmapsoftheRhoneDelta-andofLakeGenevaingeneral-aremainlybasedonhydrographicdatathatwereacquiredduringthetimeofF.-A.Forelattheendofthe19thcentury.Inthispaperwepresentresultsofanewbathymetricsurvey,basedonsingle-andmultibeamechosounderdata.Thenewdata,presentedasadigitalterrainmodel,showawell-structuredlakebottommorphology,reflectingdepositionalanderosionalprocessesthatshapethelakefloor.Asamajorgeomorphologicelement,thesub-aquaticRhoneDeltaextendsfromthecoastalplatformtothedepositionalfansofthecentralplainofthelakeat310mdepth.Theplatformedgeofthedeltaiscutby9canyons.Thesearesinuous(“mean-dering”)channelsformedbyerosionalanddepositionalprocesses,asindicatedbythesteeperosionalcanyonwallsandthedepositionalleveesonthecanyonshoulders.Thecanyonbottomsandsomeslopeareasarewrinkledbyripplesordune-likemorphologies.MorphologiesoftheunderlyingbedrockandsmalllocalriverdeltasarelocatedalongthelateralslopesofLakeGeneva.Basedonhistoricalmaps,therecenthistoryoftheRhoneRiverconnectiontothesub-aquaticdeltaandthecanyonsisre-

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sconstructed.Thetransitionfromthreetotworiverbranchesdatesto1830–1840,whentheriverbranchtotheLeBouveretlakebaywascut.ThetransitionfromtwotooneriverbranchcorrespondstotheachievementofthecorrectionanddamconstructionworkonthemodernRhoneRiverchannelbetween1870and1880.

REFERENCEMallet,H.1781:Genève.CoteBPU3E01/4.

Figure1.TopographicmodeloftheRhoneRiverDeltainLakeGeneva,establishedbymulti-beamandsingle-beamtechniques.

Figure2:MapofthelowerRhonevalleyandtheterrestrialpartoftheRhoneDeltabyMallet(1781),comparedwithmoderncoastlineand

canyons.EF:EauFroide,FR:formerbedofRhoneRiverflowingintothebayofLeBouveret,RR:mainRhoneRiverBed,VR:VieuxRhone.

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Geomorphological drivers of Holocene environmental change in Mongolia

WolfgangSchwanghart1,ManfredFrechen2,RiccardoKlinger3&BrigittaSchütt3

1Department of Environmental Sciences, Physical Geography and Environmental Change, Klingelbergstr. 27, CH-4056 Basel (w.schwanghart@unibas.ch)2Leibniz Institute for Applied Geosciences, Stilleweg 2, Section S3, Geochronology and Isotope Hydrology, D-30655 Hannover, Germany3Department of Earth Sciences, Geographic Institute, Freie Universität Berlin, Malteserstr. 74-100, D-12249 Berlin, Germany

Drylandsareamajorfocusofpalaeoclimatologicalandpalaeoenvironmentalresearchsincethesensitivityofaridandsemi-aridregionstoclimatechangeaffectsalargeportionoftheworld’spopulation.OneofthemostexcitingregionsintheworldisCentralAsia.Itssituationinthetriangleofthewesterlies,theIndianandSoutheastAsianMonsoonmadeittheplayingfieldoftheinteractionsofthesewindsystems(Fig.1)duringtheQuaternaryandbeyond.In this studywe investigate theHoloceneenvironmental evolutionof theUgiiNuurbasin in theOrkhonValley, centralMongolia,inordertogainabetterunderstandingoftheclimateandlandscapedynamicsofthestepperegioninCentralAsia.Weassessedterrestrialandlakesedimentsusingmineralogical,geochemicalandstatistical techniquesandprovideabsolutechronologiesbyradiocarbonandinfra-redstimulatedluminescencedatings.

WeprovideaHolocenechronologyofenvironmentalchangesanddiscussthesefindingswithregardtoprehistoricandhi-storichumanactivity,dominantgeomorphologicalprocessesgoverninglandscapeevolution,andtheregionalenvironmen-talcontext(Schwanghartetal.2009).Mostprominently,loessdepositionwasintensifiedduringthelateHolocene.Whilethecausesofwindblowndustneedtobeanalyzedinaregionalcontext,itshydrologicalandgeomorphologicalimplicationsareparticularlystrongatthelocalscale.Thesetemporalandspatialinteractionsbetweenaeolianandfluvialprocessesshouldbeconsideredwhenreconstructingpastenvironments inregionspronetoloessdepositionsincetheystronglyaffectthearchivesthatweanalyze.

Fig.1:Summerwindsystems,meanjulyprecipitationandpresent-daymonsoonlimitafterHerzschuh(2006).Precipitationdataisob-

tainedfromtheGLOBALSODdatabase(1994-2004).ReliefshadingisbasedonGTOPO30.

REFERENCESSchwanghart,W., Frechen,M., Kuhn,N.J.& Schütt, B. 2009:Holocene environmental changes in theUgiiNuurbasin,

Mongolia.Palaeogeography,Palaeoclimatology,Palaeoecology,279,160-171.Herzschuh,U.2006:Palaeo-moistureevolutioninmonsoonalCentralAsiaduringthelast50,000years.QuaternaryScience

Reviews,25,1-2,163-178.

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Moisture and temperature effects of char in a forest soil

SinghNimisha1,AbivenSamuel1,BoivinPascal2,&SchmidtMichael.W.I.1

1Soil Science and Biogeography, Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland (nimisha.nimisha@geo.uzh.ch)2 hepia (haute ecole du paysage, de l’ingénierie et de l’architecture),150, route de Presinge CH-1254 Jussy/Geneve

Theapplicationoffire-derivedbiomass(alsocalledcharorbiochar)tosoilisbeingconsideredasalong-termsinkforatmos-phericcarbondioxideinterrestrialecosystemsbecauseofitsslowturnoverrateinthesoil.Theeffectofcharinincreasingnutrientretentionandcropproductionhasbeenwidelyreported.Charisalsoknowntoaffectphysicalpropertiesofsoilsuchaswaterretentionandaggregation(Glaseretal.,2002),however,eventualsignificantchangesinsoilpropertiesremainsuncertain.Additionally,theadequateamounttopositivelyimpactsoilqualitywithoutanyseriousenvironmentalthreatsremainsunknown(Lehmannetal.,2006).Nonetheless,itisimportanttorealizethatcharstabilityandimpactonsoilprop-ertiesdependonfactorssuchassoilmineralcomposition,whichispoorlyunderstood.Thus,relatingcharamendmentswithsoilpropertiesrequirescarefulevaluation(i)underfieldconditionsindiversesoiltypes,(ii)undervariableenvironmentalconditions;and(iii)ofthetypeofcharusedforachievingdesiredresults.

Wehypothesizedthatthewaterretentioncapacityofthesoilwouldincreasewithincreasingcharcontent.Nevertheless,waterretentioncapacityisdependentonsoilmineralogyandcouldyieldcontradictoryresults(Tryon,1948).Temperatureandmoistureareknownimportantvariablesdrivingdecompositionofsoilorganicmatterandnutrientcyclingamongoth-ers.Consequently,anysignificanteffectonthesetwosoilpropertiesmightaffecttheCcycleonaglobalscale.Theadditionofcharwoulddarkenthesoilcolourandcouldincreaseabsorptionofsolarenergyandsoiltemperatures(Krulletal.,2004);however,thermalpropertyofsoilisinfluencedbyacombinationofwatercontent,soiltextureandsoilcolour.

Weareconductingafield-basedstudyontheeffectofdifferentratesofapplicationofcharonthetemperatureandmoisturecontentofthesoil.Thecharusedinthestudyisthereferencechar(initialsubstrateCastaneahardwood,pyrolysedat450°CunderN

2atmosphere)asusedintheringtrial(Hammesetal.,2006).Weuse15cmlong(diameter=10cm)mesocosms

insertedinthesoil,aCambisol(clay30%,orgC.4%).Thesoilandchararewellmixedandtherateofapplicationofchartothemesocosmsis3,6,12,24,48tC-charha-1 respectively, in linewithrecentapproaches forcharmediatedsoilamend-ment.

Thesoilmoisturecontentandtemperaturearemonitoredoveraseason(AugusttoNovember)usingsensors(ECH2O-TE/EC-

TM),installedat5cmdepthinsidethemesocosmsandthedatarecordedevery30minutes.Attheendoftheexperiment,soilcoreswillbesampledandwaterretentioncurvewillbedeterminedontheundisturbedsoilsamplesusingexponentialshrinkagemodel(Boivinetal.,2006).

Thiscommunicationreports the first resultsof this study.Theoutcomeof this studywould facilitate inelucidating thequantitativeassessmentoftherelationshipsbetweencharapplicationrateandthemoisturecontentandtemperaturedy-namicsofthesoilonahighertimeresolution.

REFERENCESBoivin, P.,Garnier, P., andVauclin,M. (2006).Modeling the soil shrinkage andwater retention curveswith the same

equations.SoilScienceSocietyofAmericaJournal 70,1082-1093.Glaser,B.,Lehmann,J.,andZech,W.(2002).Amelioratingphysicalandchemicalpropertiesofhighlyweatheredsoilsinthe

tropicswithcharcoal-areview.BiologyandFertilityofSoils 35,219-230.Hammes,K.,Smernik,R.J.,Skjemstad,J.O.,Herzog,A.,Vogt,U.F.,andSchmidt,M.W.I.(2006).Synthesisandcharacterisation

of laboratory-charredgrass straw (Oryza saliva) andchestnutwood (Castanea sativa) as referencematerials forblackcarbonquantification.OrganicGeochemistry 37,1629-1633.

Krull,E.S.,Skjemstad, J.O.,andBaldock, J.A. (2004).Functionsofsoilorganicmatterandtheeffectonsoilproperties. In:GrainsResearchanddevelopmentCorporationhttp://wwwgrdccomau/uploads/documents/cso000291pdf.

Lehmann, J.,Gaunt, J., andRondon,M. (2006).Bio-Char sequestration in terrestrial ecosystems-A review.MitigationandAdaptationStrategiesforGlobalChange 11,403-427.

Tryon, E.H. (1948). Effect of charcoal on certainphysical, chemical, andbiological properties of forest soils EcologicalMonographs 18,81-115.

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A tool to estimate fire intensity and chemical structure of black carbon inputs into soil

StuderMirjam1,SchneiderMaximilian1,MorenoJoséManuel2,RescoVictor2&AbivenSamuel1

1Soil Science and Biogeography, Department of Geography, University of Zurich, Winterthurerstrasse 190 8057 Zürich, (samuel.abiven@geo.uzh.ch) 2 Department of environmental science, University of Castilla – la Mancha, Toledo, Spain

“BlackCarbon”(BC)isbecomingofincreasinginterestinsoilscienceoverthepastfewyears.Blackcarbonistheresidueofbiomasspyrolysis,forexampleafterawildfire.Itscontributioncanrepresentupto40%oftheorganicmatterinthesoil(Preston&Schmidt,2006).GlobalchangemodelspredictlargeincreasesinwildfireactivityduringtheXXIstcentury,whichwouldenhanceBCcontributiontothesoil.BCwastraditionallyconsideredasaninertcomponentofthesoilcarbonpool,untiltherecentobservationthatitsdecompositionandturnoverareactuallymuchhigherthanpreviouslydocumented.Indeed,thechemicalstructureofBClargelydependsontheconditionsgivenduringthecombustionprocess.Forexample,highertemperatureandloweroxygencontentwillleadtomorecondensedandprobablymorestablecompounds.

ThechemicalstructureofBChasbeencharacterizedbymanydifferent,oftencostlymethods(Hammesetal.,2007).Inthisstudywetriedtodevelopafastandcheaptooltocharacterizetheblackcarbonchemicalstructurebypredictingtheburningtemperature.ThistoolisbasedonanindexcalculatedwithDiffuseReflectanceInfraredFourierTransform(DRIFT)spectro-scopicmeasurements.First,we tried toproposean indexbasedon lab-preparedsamples.Then,weapplied this index tosamplesfromrealwildfires.

Residuesofpyrolysisfromawoody(Castanea sativa)andanon-woody(Oryza sativa)specieswereusedasstandardtobuildupourindex.Thesampleswerepyrolised(N

2fluxeswithoutO

2)attemperaturesof200,250,275,300,350,400,500,600,700,

800,900and1000degreeCelsius.ThecharwaspreparedaccordingtothestandardproceduredescribedinHammesetal.(2006). To relate themeasurements towildfires, residues of naturally burnedMediterranean shrubs (Cistus ladanifer andPhillyrea latifolia)wereanalysed(Pérez&Moreno1998).Thesampleswerecollectedacrossagradientoffireintensity,esti-matedwiththediameteroftheremainingbranches.AllsamplesweremilledtoapowderandmixedwithdriedKBr (3%sample).TheanalyseswereperformedwithaBrukerTENSOR27DRIFTspectrometer.Thespectrawerenormalizedandpeakregions,whichvariedwithdifferentburningtem-peratures,wereidentified(1510,1420,1320,988and821cm-1).Tocalculatetheindexthemaximalpeakheightandtheareaofthepeakregionswereused.

Spectraofthelab-producedcharshowedageneralflatteningaccompaniedbyrisingabsorbancewithincreasingburningtemperatures.Samples>500°Chavebeenshowntobehighlycondensed(Schneider,personalcommunication)andwehy-pothesisedthatthemoleculesmightbetoobigandcondensedforshowingastrongandclearsignalwithDRIFTspectrom-etry.Withinthespectrafrom200to500°Cchangesofheightintheselectedpeakregionscouldbeobserved.Theresultingindexpredictedtheburningtemperature+/-50°C.Resultswereimprovedifthewoodyandnon-woodyspecieswereanalysedseparately.Thecomparisonofthelab-sampleswiththesamplesfromthewildfiresareongoingandwillbealsopresented.

REFERENCESHammes,K.,Smernik,R.J.,Skjemstad, J.O.,Vogt,U.F.,Schmidt,M.W.I.2006:Synthesisandcharacterisationof laboratory-

charred grass straw (Oryza sativa) and chestnutwood (Castanea sativa) as referencematerials for black carbonquantification.OrganicGeochemistry,37,1629-1633.

Hammes,K.,Schmidt,M.W.I.,Smernik,R.J.,Currie,L.A.,Ball,W.P.,Nguyen,T.H.,Louchouarn,P.,Houel,S.,Gustafsson,Ö.,Elmquist,M.,Cornelissen,G.,Skjemstad,J.O.,Masiello,C.A.,Song,J.,Peng,P.,Mitra,S.,Dunn,J.C.,Hatcher,P.G.,Hockaday,W.C., Smith,D.M.,Hartkopf-Fröder,C., Böhmer,A., Lüer, B.,Huebert, B. J.,Amelung,W., Brodowski, S.,Huang,L.,Zhang,W.,Gschwend,P.M.,Flores-Cervantes,D.X.,Largeau,C.,Rouzaud,J.-N.,Rumpel,C.,Guggenberger,G.,Kaiser,K.,Rodionov,A.,Gonzalez-Vila,F.J.,Gonzalez-Perez,J.A.,delaRosa,J.M.,Manning,D.A.C.,López-Capél,E.,Ding,L.2007:Comparisonofquantificationmethodstomeasurefire-derived(black/elemental)carboninsoilsandsedimentsusingreferencematerialsfromsoil,water,sedimentandtheatmosphere,GlobalBiogeochemicalCycles,21,GB2016.

Pérez,B.&MorenoJ.M.1998:Methodsforquantifyingfireseverityinshrubland-fires.PlantEcology,139,91-101.Preston,C.M.&Schmidt,M.W.I.2006:Black(pyrogenic)carbon:asynthesisofcurrentknowledgeanduncertaintieswith

specialconsiderationofborealregions.Biogeosciences,3,397-420.

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Hydration effects on microbial motility and coexistence on unsaturated rough surfaces

GangWang&DaniOr

Soil and Terrestrial Environmental Physics (STEP), Department of Environmental Sciences (D-UWIS), Swiss Federal Institute of Technology, Zurich (ETHZ), Universitaestrasse 16, CH-8092, Zurich (gang.wang@env.ethz.ch)

Microbialmotility isrecognizedasakeymechanisminbiodiversitymaintenanceofecosystem(Reichenbachetal.2007),whichplaysadominantroleinmostaspectsofbioremediation,biochemicalnutrientcycling,plantrhyzosphere,redoxreac-tionsandpathogendispersal(Fenchel2002;Madsen2005).Quantitativedescriptionofmicrobialmotilityandotheractivi-tiesinsoilsishinderedbyporespacecomplexityandhydrationdynamics.Unsaturatedconditionsarecommoninnature(Barbara &Mitchell 2003), form fragmented aquatic habitats that are too small to support full immersion ofmicrobestherebyforcingstronginteractionswithmineralsurfaces,andresultinsignificantrestrictionofmicrobialmotility.Anewhybridmodelwasdevelopedtostudythe influenceofsurfacehydrationonmicrobialmotilityandits impactonspeciescoexistenceonunsaturatedroughsurfaces.

Simulationsbasedongeneralparametervaluesfromliteraturepredictreducedcolonyexpansionratesandcorrespondinglyincreasedspeciescoexistencetimeunderdrierconditions,whichareingeneralagreementwithexperimentalobservations(Dechesneetal.2008).Undermatricpotentialshigherthan-0.5kPa(wet),microbialcoloniesgrowfastatanaveragerateofcolonyexpansionexceeding421±94µm/hr;therateofcolonyexpansiondroppedto31±10µm/hrat -2kPaandlevelledatlowermatricpotentials;asexpected,nosignificantcolonyexpansionwasobservedatmatricpotentialof-5kPabecauseofthesub-micrometricandfragmentedaquaticformationandtheresultingcapillarypinningforces.Drierconditionsreducemotilityandenhancecoexistenceoftwocompetingspecies(indefinitecoexistenceformatricpotentialslowerthan-2kPa),conversely,nocoexistencewasfoundformatricpotentialshigherthan-0.5kPa.Thisstudyexploresfundamentalmecha-nismsofphysicalconstraintsofporefeaturesandcapillarypinningforceonrestrictingmicrobialmotility,henceaffectingspeciescoexistenceonunsaturatedroughsurfaces.Thefindingofclosedependenceofspeciescoexistencetimeonsurfacehydration(hencemotility)alsoreflectsthereductionofnutrientfluxinterceptionbythemorecompetitivespecies,there-strictionofspatialinteractionsandnutrient“shadowing”byrapidlyexpandingcoloniesunderdrierconditionsthatpro-motespeciesco-existenceonunsaturatedroughsurfaces.

REFERENCESBarbara,G.M.&Mitchell,J.G.2003:Marinebacterialorganisationaroundpoint-likesourcesofaminoacids.FEMSMicrobiol.

Ecol.43,99-109.Dechesne,A.,Or,D.,Gulez,G.& Smets, B.F. 2008: Theporous surfacemodel, anovel experimental system for online

quantitativeobservationofmicrobialprocessesunderunsaturatedconditions.Appl.Environ.Microb.74,5195-5200.Fenchel,T.2002:Microbialbehaviorinaheterogeneousworld.Science296,1068-1071.Madsen,E.L.2005:Identifyingmicroorganismsresponsibleforecologicallysignificantbiogeochemicalprocesses.Nat.Rev.

Microbiol.3,439-446.Reichenbach,T.,Mobilia,M.&Frey,E.2007:Mobilitypromotesand jeopardizesbiodiversity inrock-paper-scissorsgames.

Nature448,1046-1049.

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11. Decision oriented modelling of the geosphereH.-R. Egli, W. Haeberli, C. Hegg, O. Smrekar, M. Stauffacher

Swiss Academic Society for Environmental Research and Ecology (SAGUF)Swiss Geographic Society, Swiss Geomorphological Society

11.1 BalinD.,MetzgerR.,FalloJ.-M.,ReynardE.:Integrativehydro-geomorphologicmodellinginalpineregions:scientificandoperationalchallenges

11.2 BilgotS.,ParriauxA.:Usingpredispositionfactorsforlandslidehazardassessment:anewGIS-basedmethodology

11.3 BinderC.,FeolaG.,Garcia-SantosG.,YangJ.:Integrativemodellingofpesticideuseindevelopingcountries

11.4 DurrandeN.,RenardP.,GinsbourgerD.:AclusteringmethodforuncertaintyquantificationappliedtoCO2seque-stration

11.5 HaeberliW.:4Dinformationonclimate-drivengeosystemchangesinhighmountainareas-experiencesandperspec-tives

11.6 MilnesE.:Simulation-basedriskassessmentofsuperimposedgroundwatersalinisationprocesses

11.7 PlattnerG.-K.:TheRoadtoClimateStabilization:InsightsfromCarbonCycle-ClimateModels

11.8 WeigelA.:Seasonalclimatepredictions:Fromtheorytoend-userapplications

11.1

Integrative hydro-geomorphologic modelling in alpine regions: scientific and operational challenges

DanielaBalin1,RichardMetzger2,Jean-MichelFallot1,EmmanuelReynard1

1 Geography Institute, University of Lausanne, CH-1015 (daniela.balin@unil.ch)2 Geomatic and Risk Analysis Institute, University of Lausanne, CH-1015

Hazardandriskassessmentrequire,besidesgooddata,goodsimulationcapabilitiestoallowpredictionofeventsandtheirconsequences. Progresses have been done in building different modelling structures (conceptual and physically based,lumpedanddistributed)atdifferentscales,withdifferentamountsofinputdataandtogetherwithdifferentcalibrationprocedures.Hazardassessmentoftenrequiresinvolvementofdecisionmakersandthusanimportantchallengeistheevaluationofthecredibilityofthescientificresultsandthecommunicationoftheuncertainty.

Thepresentstudyintroducesanintegratedapproachbasedonthecouplingofhydro-geomorphologicmodels,abletocopewithuncertaintyofinputdataandmodelparametersinordertoperformadynamicmodellinginspaceandtimeofthemainrainfalltriggeredhydro-geomorphologicprocesses.Theroleofuncertaintyasatooltolearnhowinputdatacouldbeusedtoevaluatedifferentmodellingstructuresatdifferentscaleshasbeenalsoinvestigated.

Thestudyregionisrepresentedbytwosmallalpinecatchments,thenaturalreserveof«VallondeNant»(13km2)andtheTintaz catchment in the urbanised Verbier region. The hydrologicalmodel in this study is based on theWater BalanceSimulationModel,WASIM-ETH(Schullaetal.,1997),afullydistributedhydrologicalmodelthathasbeensuccessfullyusedpreviouslyinthealpineregionstosimulaterunoff,snowmelt,glaciermelt,andsoilerosionandimpactofclimatechangeonthese.Thismodelisintendedtobecoupledwithslopestabilitymethodstosimulatethespatialdistributionoftheini-

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eretiationareasofdifferentgeomorphicprocessessuchasdebrisflowsandrainfalltriggeredlandslides.

TocalibratetheWASIM-ETHmodel,theMonteCarloMarkovChainBayesianapproachwillbeprivileged(Balin,2004,Schaeflietal.,200).Giventhatthespatialuncertaintyofrainfallisanimportantfactorofuncertaintyinthehydrologicalmodellingandgiventhehighvariabilityoftherainfallinalpinecatchments,aquitedensenetworkofmeteorologicalstationshasbeenimplementedtobettercalibratethehydrologicalmodel.Eachstepinthehydro-geomorphologicriskassessmentundertakesuncertainty:evaluationofthemainsourcesofuncertaintyaswellastheevaluationandcommunicationofuncertaintyisanimportantaspectoftheproposedmethodology.TheBayesianapproachoffersagoodcompromisebetweenmodeleffi-ciencyandtimeconsumptionandrepresentsastraightforwardwaytodealwithdifferentsourcesofuncertainty,asnowa-daysthisisanimportantrequirementofthedecisionmakersinvolvedinriskassessment.

REFERENCESBalin,D. (2004). “HydrologicalBehaviour through experimental andmodellingapproaches.Application to theHaute-

Mentuecatchment.”ThèseEPFln°3007.FacultéEnac,EPFl,Lausanne,Suisse.Schaefli B, TalambaBalinD.,MusyA,.2007. “Quantifyinghydrologicalmodeling errors through amixture ofnormal

distributions”JournalofHydrology332(3-4):303-315Schulla,J,Jasper,K.1998/2000:„ModellbeschreibungWaSiM-ETH“;InstitutfürGeographie,ETHZürich,167S.

11.2

Using predisposition factors for landslide hazard assessment: a new GIS-based methodology

BilgotSéverine1,ParriauxAurèle1

1 EPFL ENAC IIC GEOLEP, Station 18, CH-1015 Lausanne (severine.bilgot@epfl.ch)

Switzerland isexceptionallysubjectedto landslides; indeed,about10%of itsarea isconsideredasunstable.Makingthisobservation,itsDepartmentoftheEnvironment(BAFU)introducedin1997amethodtorealizelandslidehazardmap.Itisroutinelyusedbut,likemostofthemethodsappliedinEuropetomapunstableareas,itismainlybasedonthesignsofpreviousorcurrentphenomena(geomorphologicmapping,archiveconsultation,etc.)eventhoughinstabilitiescanappearwherethereisnothingtoshowthattheyexistedearlier.Furthermore,thetranscriptionfromthegeomorphologicmaptothehazardmapcanvaryaccordingtothegeologistorthegeographerwhorealizesit:thismethodisaffectedbyacertainlackoftransparencyandisnotreallyefficienttoforecastlandslides.

Theaimofthisprojectistointroducethebedrockofanewmethodforlandslidehazardmapping;basedoninstabilitypre-dispositionassessment,itinvolvesthedesignationofmainfactorsforlandslidesusceptibility,theirintegrationinaGIStocalculatealandslidepredispositionindexandtheimplementationofnewmethodstoevaluatethesefactors;tobecompeti-tive,theseprocesswillhavetobebothcheapandquick.

Aftershowingthatcohesionandhydraulicconductivityofloosematerialswerestronglylinkedtotheirgranulometryandplasticityindex,weimplementedtwonewfieldtests,onebasedonteledetectionandonecoupledsedimentometricandbluemethylenteststoevaluatetheseparameters.Thehydraulicconductivityoffracturedrockswasobtainedfromtheanalysisoftheirgeometricalproperties(fracturesdensity,aperturesizeandorientation).TheotherfactorswereextractedfromDEMandhydrologicmapping.

Weaddedalastfactorrelatedtothepredispositionofthegeotype(newclassificationforgeologicformations,basedonge-neticstandardsforloosematerialandonlithologicstandardsforhardrock)toslopeinstabilityprocess:thelatterenabledustointegrateattributespropertoeachgeotypes (over-consolidationforgroundmoraines,stratificationsforglaciolacus-trinedeposits,etc...)andwhichwouldbelongandcomplextointegratetoaGIS.

Afterward,weimplementedanArcGis®toolboxallowingtoleadtoalandslidesusceptibilityindex.Finally,weappliedthismethodology(fromfieldsurveytoGISoperations)totensitesindifferentcontextsinSwitzerland.Thisnewmethodologycanbeconsideredasacheapandefficientwaytoforecastlandslides.

REFERENCESLateltin,O.:Priseencomptedesdangersdusauxmouvementsdeterraindanslecadredesactivitésdel’aménagementdu

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Figure1.ApplicationtotheTraverslandslide

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ere11.3

Integrative modelling of pesticide use in developing countries

BinderClaudiaR.12,FeolaGiuseppe1,Garcia-SantosGlenda1,Yang,Jing1

1 Department of Geography, University of Zurich2 Institute for System Science Innovation and Sustainability Research, University of Graz, Austria

Thelivelihoodofsmallfarmersindevelopingcountriesdependsontheirabilitytoemployecologicallyandeconomicallysoundproductionmethods.Whileproperlyappliedpesticidesreduceyieldlossesupto40%andimproveproductquality,theirmisusemight cause serious human health and environmental problems. TheWorld Health Organization (WHO)(1990a)estimatesanannualworldwidetotalof3millioncasesofacutepoisoningwith220,000deaths.Oneofthecentralquestionsiswhy,despitealltheeffortsbeingmadeinresearch,nosignificantimprovementsinunder-standingandmodelingfarmers’decision-makingandconnectingittoenvironmentalandhumanhealthimpactshavebeenmade.Antleetal.(2001)statethatoneofthereasonsisthesegregateddisciplinaryresearchwhichleadstotheproblemthatdifferentscientificinvestigationscannotbelinkedtoprovideasystemunderstandingthatincludessocialandnaturalsci-encevariables.However,thisunderstandingisindispensableforsciencemodelsthatprovideasoundsystemunderstandingandthus,resultsthatarecomprehensibleandusefulforpolicymakers.

Thispaperpresentsanintegrativemodellingapproachtosimulateandassesstheeffectofmeasuresforreducingthehumanhealthandenvironmentalrisksfrompesticideuse.Figure1showstheconceptualapproachunderlyingthemodelbuildingprocessandthemethodsusedthereby.

Mental Model Approach

Sensitivity A.Measurements

System Analysis Workshop

Survey

Human and environmental risk assessment

Farmers’ perceptions& decision-making

Scenario development

Spatially explicit dynamic risk assessment

Simulation and assessment of mitigation strategies

Calibrated spatially explicit risk assessment model

Simulation model

Farmers decision-making model

AssessmentStrategies for reducing risks

Figure1.Methodologicalapproachtakenfordesignedthesimulationmodelintheresearchproject.Methodswith1transdisciplinary

methods

Thesimulationmodeliscomposedoftwosub-modelsafarmersdecision-makingmodelandaspatiallyexplicitriskassess-mentmodel.Farmers’ deci­si­on-maki­ng modeldeterminestheamountandtypeofpesticideusedandthetypeandfrequen-cyofusageofprotectiveequipmentduringapplication.Thismodelisbasedonapreliminarytransdisciplinaryanalysisoffarmers’perceptionsonthepotentialrisksofpesticideapplicationandtheirsystemview(Schoell&Binder,2009)andtheIntegratedAgentCentred(IAC)Framework(Feola&Binder,2009).Resultsregardingtheuseornonuseofprotectiveequip-mentshowthatthevariablesmostlyaffectingthisdecisionwere(i)theperceptionofequipments’comfort,(ii)thepracticeofreadinglabels, (iii) thedescriptivesocialnormsand (iv) theperceivedhealthimpact (FeolaandBinder,accepted).Thethirdandfourthvariableallowfordefiningadynamicmodelwhichspecificallyincludesfeedbackmechanismsastheeffectofindividualactiononsocialnorm.

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Thepresentationwill focuson themethodological approach takenhighlighting theadvantagesofperformingout-fronttransdisiplinaryresearchtodeterminethemainvariablesrelevantforthesystem.

REFERENCESFeolaG.&BinderC.R.Theorypaper–whichdoyouwanttocite??

FeolaG.&BinderC.R.Whydon‘tpesticideapplicatorsprotectthemselves?ExploringtheuseofPersonalProtectiveEquipmentamong

Colombiansmallholders.InternationalJournalofOccupationalandEnvironmentalHealth,inpress.

SchöllR.&,BinderC.R.,ComparingSystemVisionsofFarmersandExperts,Futures,inpress.

SchöllR.&BinderC.R.,2009,Systemperspectivesofexpertsandfarmersregardingtheroleoflivelihoodassets:ResultsfromaStructured

MentalModelApproach,JournalofRiskAnalysis,29(2):205-222.

WHO1990bSafeuseofpesticides.FourteenthreportoftheWHOExpertCommitteeonVectorBiologyandControl.Geneva,WorldHealth

Organization,1990(WHOTechnicalReportSeries,No.813).

11.4

A clustering method for uncertainty quantification applied to CO2 sequestration

DurrandeNicolas1,RenardPhilippe2,GinsbourgerDavid1,2

1 Dep. of mathematics, Ecole des Mines de Saint-Etienne – 29 rue Ponchardier 42000 Saint-Etienne France, (durrande@emse.fr)2 Centre of hydrogeology and geothermics, University of Neuchâtel – Rue Emile-Argand 11, CH - 2009 Neuchâtel - Switzerland (philippe.renard@unine.ch, david.ginsbourger@unine.ch)

InordertoreducetheatmosphericemissionofCO2duetohumanactivities,onepossibility is tostoreCO

2 ingeological

reservoirs.TheprincipleistoextracttheCO2producedbyapollutingfactory(acoalfiredpowerplantforinstance)andto

injectitintoageologicalreservoirsuchasadeepsalineaquifer.Ifthecaprock'squalityisgood,theCO2willbetrappedand

willprogressivelyturnintosediments.

Todecideupontheviabilityofsuchproject,oneofthemainchallengesistoquantifytheriskofCO2leakage.Asalltheleak-

agescenariidependonthegrowthoftheCO2plume,itisnecessarytostudyitsexpansionbynumericalsimulation(Fig.1).

However,theinputsofthesimulation(permeabilityandporosityfields)arerandom,andsimulatingonesingleinjectionschemewithafinitevolumemethodaccountingtheproperequationofstatesforsupercriticalCO2takesaround2days(20yearsofinjectionwitha2dimensionalmodel).

AsclassicalMonte-Carlomethodsareunaffordable,themethodweusehereisasdescribedbyCaersin[1].Theaimistoselectalimitednumberofsimulationrunsbyapplyinganonintrusivemethodbasedonaproxysimulator(cheap-to-evaluatelow-fidelitymodel). Following [2], kernelmethodsareused inorder to linearize thedata,which is supposed to improve theclusteringprocedure.Themethodconsistsof5steps:

• Generatenfieldsofpermeabilityandporosity• Useaproxysimulatortocomputethenapproximatesolutions• Defineadistancebetweenthesolutionsandcreateamapping.Thistransformationmaybebasedonkernelmethodsfor

greaterlinearity.• FindNcentresofclusters• RunthesimulatorfortheNselectedpoints.

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ereTheflowsimulationisperformedusingthesoftwareTough2witha1Mt/yinjectionrateduring20years.Theproxysimula-

torisashortenTough2simulationofa1yearinjection.Thenumberofinitialfieldsgeneratedisn=100andthenumberofcompletesimulationsisN=10.Inordertoevaluatetheefficiencyofourmethod,weperformaclassicalMonte-Carloanalysisusing100completesimulations.TheresultsareshownonFigure2:

Thisworkillustratesthatproxysimulatorscanbeusedtoefficientlyselectrepresentativesimulations.HeretheCPUsimu-lationtimecanbedividedbyoneorderofmagnitudewhilekeepinggoodestimatesoftheprobabilityofpresenceofCO

2.

Howeverthedistancedefinitionseemstohaveagreatimpactonthefinalresults.Futureworksmayfocusontheissueofselectingwell-suiteddistancesforimportancesampling.

Moregenerally,theproposedapproachallowstoimprovetheefficiencyoflargescaleandcomplexmodellingunderuncer-taintyfordecisionmaking.

Figure1.Exampleofpermeabilityfieldandresultofa20yearsinjection

Figure2.ComparisonbetweenclusteringmethodandMonte–Carlo

REFERENCES[1]J.Caers.2008-Distance-basedstochasticmodelling:theoryandapplications.TechnicalReport21,StanfordUniversity,

EnergyresourcesEngineeringDep[2]C.Scheidt,J.Caers.2008-Uncertaintyquantificationusingdistancesandkernelmethods-applicationtoadeepwater

turbiditereservoir.Technicalreport,StanfordUniversity,EnergyresourcesEngineeringDep[3]V.Vapnik.1995-TheNatureofStatisticalLearningTheory.Springer

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4D information on climate-driven geosystem changes in high mountain areas - experiences and perspectives.

WilfriedHaeberli1

1Glaciology,Geomorphodynamics&Geochronology,GeographyDepartment,UniversityofZurich

Integratedgeoinformation systemscombiningdata,models and scenariosare increasinglyneeded toanticipatedevelop-mentsofcomplexgeosystemsbeyondtheempiricalknowledgebasisfromthepast.Suchgeoinformationsystemsprimarilyprovideanoverviewoftheavailableknowledgeandunderstandingconcerningthemostimportantprocesses,subsystemsandtheirpotentialinteractions.Asaconsequenceofoftenincompleteorevenmissing(spatiotemporal)information,theymustapplyrelativelysimpleandrobustmodels,whichneedexaminationbymoresophisticatedprocess-orientedmodels.Theyrenderthecorrespondingscientificreflection(assumptions,hypotheses,scenarios)transparent,quantifyresultsinthespaceandtimedomainandindicateknowledgegaps.Perhapsmostimportantly,theydemonstratetheusefulnessof,andtheneedfor,consideringcomplexsystemsandlongertimescales.However,theyare-andwillalwaysbe-farfromperfectandneedcontinuousdevelopmentinviewofongoingrapidchangesinnature,technologyandscientificunderstanding.Models of abiotic subsystems such as snow and ice conditions, water supply or hazards from rock falls, debris flows,avalanchesandfloodsarealreadywelladvancedanduseful.Bioticsubsystems–especiallyvegetationasrelatedtoclimatechange,icevanishingandeffectsofgrazing–arelesswellcoveredbyrobustspatialmodelsapplicableinhigh-mountaintopography:anurgentresearchneed.ExperiencesarepresentedfromacasestudycarriedoutintheUpperEngadin,easternSwissAlps,withintheframeworkoftheNRP48andperspectiveswillbediscussedinviewofnewlakesforminginrapidlydeglaciatingmountainranges.

11.6

Simulation-based risk assessment of superimposed groundwater salinisation processes

EllenMilnes1

1Centre d’hydroéologie CHYN, Université de Neuchâtel, Rue Emile-Argand 11. CH- 2007-Neuchâtel

Groundwatersalinisationisaworld-widemajorgroundwatercontaminationissueandisrelatedtomultipleprocesses,suchasseawaterintrusion,agrochemicalpollution,geogeniccontaminationandirrigation-inducedpollution.Insalinityaffectedaquifers,theobservedconcentrationoftotaldissolvedsolidsmayresultfromthesuperpositionofseveralsalinisationpro-cesses.Inareasaffectedbygroundwatersalinisation,correctidentificationofthespatialdistributionanddynamicinterplayofthesuper-imposedsalinitycomponentsiscrucial,sincetherespectiveremedialorconservationmeasuresmaybeentirelydifferent.

Identificationofdifferentoriginsofsalinisationcanbeconsideredaseparatefieldinhydrogeologicalresearchandiseffici-entlyaddressedbymeansvarioushydrogeochemical techniques (e.g.Custodio,1997;Vengoshetal.,1999).Asopposedtosimplesalinitymeasurements,sophisticatedtechniquesthatyieldclearinformationabouttheoriginofsalinityareoftencostlyandusuallyonlyyieldsnap-shotsintimeandspace.Combininginformationontheoriginsofsalinityfromsuchin-vestigationswithnumericalsimulationsisthereforeapromisingstrategytoinvestigatetheinterplaybetweendifferentsa-linisationprocesses.

Vulnerability and risk assessments are becoming a standard approach in groundwatermanagementwhen dealingwithwaterqualityandcontaminationissues.Themostcommonlyusedvulnerabilitymappingproceduresarebasedonempiricalpointratingsystemsthatbringtogetherkeyfactors.Ithasbeenfoundthatthevulnerabilityandcontaminationriskcanrarelybepredictedwiththesekeyfactorswhichiswhythereisagrowingneedforphysicallybasedriskandvulnerabilityassessments(Gogu&Dassargues2000).

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ereAsimulation-basedsalinisationriskassessmentmethodologyisproposedthatallowsmappingofareasatriskwithrespect

todifferentsalinisationprocesses.Anumericalgroundwatersimulationprocedureispresentedwhichallowsdecompositionofameasuredbulksalinitydistributionintocomponentsderivedfromdifferentsalinisationprocesses.Inafirststep,anu-mericalgroundwaterflowandtransportmodelaccountingforallidentifiedsalinisationprocessesiscalibrated,usingtheobservedsalinitydistribution.Then,theobservedsalinitydistributionisreplacedbythesimulatedsalinitydistribution.Byadaptingtheboundaryconditionsofthemodeleachsalinisationprocesscanthenbesimulatedseparately.Thesimulationresultsarethenusedtoobtainriskindexdistributionsforeachsalinisationprocess,reflectingthespatialvariationofpos-siblefuturerelativesalinityincreasewithrespecttoagivenprocess.Inthelaststep,theseriskindexdistributionsarethenoverlainwithdefinedthresholdsalinities,revealingareasrequiringremediationorconservationmeasures.

ThedifferentstepsofthesalinisationriskmappingprocedureareillustratedonarealaquifersysteminSouthernCyprus(Akrotiri),wherethreemajorsalinisationprocessesaresuperimposed(seawaterintrusion,evaporationandirrigation-indu-cedsalinisation),revealingthepossibleusefulnessingroundwatermanagementdecision-makingprocess.

REFERENCESCustodio, E. 1997: Studying,monitoring and controlling seawater intrusion in coastal areas. In:Guidelines for Study,

MonitoringandControl,FAOWaterReports7-23,11(1).Gogu,R.C.&Dassargues,A., 2000:Curent trendsand futurechallenges ingroundwatervulnerabilityassessmentusing

overlyandindexmethods.549-559.EnvironmentalGeology39(6).Vengosh,A.,SpivackA.,ArtziY.,AvnerA.1999:Geochemicalandboron,strontiumandoxygenisotopicconstraintsonthe

originofthesalinityingroundwaterfromtheMediterraneancoastofIsrael.WaterResourcesResearch35(6),1877-1894.

11.7

The Road to Climate Stabilization: Insights from Carbon Cycle - Climate Models

Gian-KasperPlattner1

1Climate and Environmental Physics, Physics Institute, University of Bern & IPCC WGI TSU, University of Bern

TheUNFrameworkConventiononClimateChangecallsfor"stabilizationofgreenhousegasconcentrationsintheatmos-phereatalevelthatwouldpreventdangerousinterferencewiththeclimatesystem".Futureclimatestabilizationwillulti-mately require stabilizationof atmospheric greenhousegas concentrations and substantial reductions in anthropogenicgreenhousegasemissionscomparedtopresent-dayemissions.ForCO2,themostimportantanthropogenicgreenhousegas,theamountofcarbonemissionsthatcanbereleasedinordertoreachagivenCO2stabilizationtarget(i.e.the"allowable"emissions)willdependonhowmuchoftheextraCO2willberemovedfromtheatmospherebynaturalCO2sinks,mainlytheoceansandthelandbiosphere.Oceanandlandbiospherecurrentlyremoveabout50%oftheman-madeannualCO2emissions,andtherebysubstantiallyhelpedmitigatingtheriseinatmosphericCO2overthelast200years.Unfortunately,thesenaturalsinkscannotbeexpectedtocontinueforever.Observationalevidenceandevidencefromcoupledclimate -carboncyclemodelssuggestthat increasingCO2levelsandclimatechangewill likelydecreasetheabilityofthenaturalsystemtotakeupextraCO2inthefuture,leavinglargerfractionsoftheanthropogenicCO2emissionsintheatmosphere,andthereforefurtherraisingCO2levelsandacceleratingclimatechange.ThereductionsinglobalcarbonemissionsforagivenCO2stabilizationtargetthusneedstobesubstantiallylargerifcarboncycle-climatefeedbacksareaccountedfor.Inmypresentation,Iwill(1)quantifytheimpactofcarboncycle-climatefeedbacksontheprojected"allowable"emissionforCO2/Climatestabilizationinthecurrentgenerationofcarboncycle-climatemodelsand(2)highlightuncertaintiesinthemodelrepresentationofcarboncycleprocessesresulting insubstantial spread inboththemodelresponseto increasingatmosphericCO2andclimatechange.

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Seasonal climate predictions: From theory to end-user applications

Andreas Weigel1

1Federal Department of Home Affairs FDHA Federal Office of Meteorology and Climatology MeteoSwiss, Zurich

Seasonalforecasting,i.e.theprovisionofinformationontheexpectedtendencyoftheclimateofthecomingmonthsandseasons,hasbecomeawell-establishedtechniquewithapplicationsworld-wide.Indeed,seasonalforecastsaresuccessfullyappliedforclimate-riskmanagementinmanyclimate-sensitivesectorssuchasenergy,health,watermanagement,agricul-tureandtheinsuranceindustry.

Since 2005,MeteoSwiss issues seasonal forecasts on anoperational basis, both for thepublic and forprivate customers.However,duetothewiderangeofuncertaintiesinvolved,seasonalclimatepredictionsareinherentlyprobabilistic,requiringsignificanteffortsbothfromforecastprovidersandusers.Whiletheformerneedtomakesurethattheuncertaintiesareappropriatelyquantifiedandcommunicated,itisthetaskofthelattertomakeoptimumusetheuncertaintyinformationprovided.ForapplicationsincentralEurope,thesechallengesarefurtheraggravatedbythefactthatthepredictionskillisverylowinthisregion,i.e.thatthepredictableclimatesignalisoftenveryweakincomparisontotheunpredictablenoise.

Inthispresentation,anoverviewofourexperiencegainedinthefieldofseasonalforecastingwillbepresented.Inparticular,thefollowingissueswillbediscussedandillustratedwithexamples:(i)Howcantheuncertaintyrangeofclimatepredictionsbeaccuratelydetermined?(ii)Howcantheuncertaintiesandthepredictionskillofseasonalforecastsbeaccuratelycommu-nicatedtotheusercommunity?Andfinally:(iii)Howcanseasonalforecastsbesuccessfullyapplied,evenifthepredictionskillisverylow?