eosc221 - university of british columbia · eosc221 clastic (terrigenous / siliciclas9c)...

EOSC221

CLASTIC(Terrigenous/Siliciclas9c)SEDIMENTARYROCKS

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•  BroadDefini9ons•  AsIndicatorsoftransportdistance•  ConglomeratesandBreccias

–  Environmentsofdeposi9on

–  Classifica9onandTerminology

•  Sandstones–  Basiccomponents

–  Classifica9on–  Environmentofdeposi9on&provenance

–  Provenanceandtectonicregime

•  Mudrocks–  Textures–  Colour–  Mineralcomposi9on

–  Marinemudrocks

–  Nonmarinemudrocks

–  OrganicrichmudrockshOp://www.sandatlas.org/wp-content/uploads/00034.jpg

LECTUREOUTLINE

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BroadDefini5ons

•  Producedbyweathering/erosionofpreexis9ngrocks

•  ComposedofGRAINS

•  Mudstones:<0.0625mm

•  Sandstones:0.062–2mm

•  Gravels/Conglomerates/Breccias:2mm+

•  SeeStandardGrainsixechartTable13-1intextbook

hOp://en.wikipedia.org/w/index.php?9tle=File:Wentworth-Grain-Size-Chart.pdf&page=1

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AsIndicatorsofTransportDistanceremembertheseareALLgenerali0es!•  1.Chemical(mineralogical)maturity•  MineralStabili9esatsurfaceTemperatures:•  “ReverseofBowen’s

Reac9onSeries”–  Quartz/Zircon/Tormaline

Chert/PolycrystallineQuartz–  Muscovite–  Microclinefeldspar–  Orthroclasefeldspar–  Plagioclasefeldspar–  Hornblende/Bio9te–  Pyroxene–  Olivine

IncreasingStabilityatsurface

temperaturesandpressures

hOp://rbmason.ca/databank/mineral/quartz2.html

PolycrystallineQuartz

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hOp://en.wikipedia.org/wiki/File:ShaleUSGOV.jpghOp://en.wikipedia.org/wiki/File:Conglomerate_core_sec9on.jpg

Conglomerate Shale(mudstone)

•  2.Texturalmaturity

•  i.Decreasinggrainsizefromsource

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•  ii.Increasinggrainroundingawayfromsource

hOp://en.wikipedia.org/wiki/File:Rounding_%26_sphericity_EN.svg

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•  iii.Increasedsor9ngawayfromsource–reduceamountof‘matrix’

hOp://en.wikipedia.org/wiki/File:Sor9ng_in_sediment.svg

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Probablybrecciasandconglomeratesveryclosetosource

Increasing%quartz,increasedsor9ng,reducedgrainsize,

Increasedroundingofgrains

Increasing%quartz,increasedsor9ng,reducedgrainsize,Increasedroundingofgrains

Conglomeratesandbreccias•  RocksthatcontainCLASTSinafinergrainedmatrix•  Conglomerates–ROUNDEDclasts.,>30micronmatrix•  Breccias:ANGULARclasts,>30micronmatrix

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Conglomerate:roundedclasts Breccia:angularclasts

Conglomerates–SomeexampleofEnvironmentsofdeposiFoni.Beachenvironments-conglomeratesmayrepresentposi9onofshoreline-Commonintransgressive(risingsealevel)sequences“basalconglomerates”

hOp://csmres.jmu.edu/geollab/fichter/SedRx/depomodels.PDFpropertyofauthor

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ii.Fluvial:-Typicallywellrounded-Highconglomerateconcentra9ontypicalofimmaturerivers

hOp://en.wikipedia.org/wiki/File:Waimakariri01_gobeirne.jpg

propertyofauthor

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Clastsmaydemonstrateimbrica9on

hOp://en.wikipedia.org/wiki/File:Imbricated_fabric_overlay.jpg

FLOWDIRECTION

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-Inmatureriverstendtoberestrictedtobaseofchannels

hOp://en.wikipedia.org/wiki/File:Rio-cauto-cuba.JPGhOp://www.bbc.co.uk/scotland/learning/bitesize/higher/geography/physical/hydrosphere_rev3.shtml

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iii.AlluvialFans:-coneshapedstructureosenatabruptbreakinslope-deposi9onosenasdebrisflowsandin“braidplains”infrontofthefan

hOp://upload.wikimedia.org/wikipedia/commons/1/1e/Gigan9c_Alluvial_Fan_Being_Uplis_by_New_Fault.jpg

DeathVallley

Iran

hOp://en.wikipedia.org/wiki/File:Alluvial_fan_in_Iran.jpg

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iv.Glacial:-Glacial9ll(9llites)-Depositedbyretrea9ngglacier

hOp://upload.wikimedia.org/wikipedia/commons/3/34/Glacier_mouth.jpg hOp://en.wikipedia.org/wiki/File:MorainesLakeLouise.JPG

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Conglomerates/BrecciasclassificaFon&terminology-  clasttypes

-Polymict:3ormoredifferentclasttypes-Oligomict:2-3differenttypesofclast-Monomict:only1clasttype

-  MatrixsupportedMorematrixthanclasts

-  ClastsupportedMoreclaststhanmatrix

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Sandstones

Basiccomponents1.   FrameworkGrains(1/16-2mm)

2.   Matrix(material<30um)

3.   Cement:mineralsprecipitatedinbetweengrainsinporespace

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1cm

1mm

ClassificaFon-  Lotsofdifferentclassifica9onschemes–wewillusePevjon1973

-  Basedon1.%MATRIX(material<30umbetweengrains):-Arenites0–15%matrix-Greywackes15–75%matrix-Mudstones75%+matrix

Arenites Greywackes

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0 15 75 100

Mudstones

Increasing%ofmatrix

Q

F L

2.GRAINCOMPOSITION:Q:QUARTZ F:FELDSPAR L:LITHICS(rockfragments)

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60%Q/20%F/20%L

ThisosencalledaQFLdiagram

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Q

F L

2.GRAINCOMPOSITION:Q:QUARTZ F:FELDSPAR L:LITHICS(rockfragments)

20ThisosencalledaQFLdiagram

2525%Q/40%F/35%L

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Q

F L

Dependingonrela9vepropor9onofgrainsarenitesandgreywakesaregiventhefollowingprefixes:-Quartz(high%quartzgrains)-Arkoseor“arkosic”“feldspathic”forahigh%offeldspar-Lithicforhigh%ofrockfragments

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QUARTZARENITE

Q

F L

Furthersubdivisionsosenusedaswell……..

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QUARTZARENITE

LithicArkose

Fledspathiclitharenite

Lithicsubarkose

Subarkose

Sublitharenite

500

5

5015

75

lithicarenite

arkosicarenite

arkose

lithicarkose

subarkose

sublitharenite

quartzarenite

525

Pullingthematrix/grainclassifica9ontogether………..

-Useprefixbasedongraintypefollowedbysuffixbasedonmatrixtype,either“arenite”for0-15%or“wacke”for15–75%matrix

ARENITES

WACKES

MUDSTONES

QW:QuartzwackeLGW:lithicgreywackeFGW:FledspathicgreywackeMst:Mudstones

QW

LGWFGW

Mst

Q

F

L 23

Felspa0clitharenite

SandstonesenvironmentsofdeposiFonandprovenance-  FoundinMANYenvironments

-  Alluvial,Fluvial,Glacial,Aeolian(land),shallowmarine/deepmarine

-  Wheremightyouexpecthighlymaturequartzarenites?

ALLUVIAL FANGRAVEL BEACH

BASIN

SUBMARINE FAN

SUBMARINE FAN

BASIN

Reef

OffshoreCarbonates

ALLUVIAL FANBRAIDED RIVER

MEANDERING RIVER

BEAC

HDELTA

shoreline sands

hummockybeds

tidalsandbars

SHELFLa

goon

barrierisland

Tidal fla

t

Salt panDesertdunes

A LONGSYSTEM

A SHORTSYSTEM

Not to scale

Not to scale

Supertidal Intertidal Subtidal SHALLOW SHELF

BASIN

DEEP SHELFBARRIERREEF

LAGOONTIDAL FLAT

Supertidal Intertidal Sub- tidal

patch reefstromatolites

salt pan

algallaminates

mudcracks

tidal channels

tidal sand bar

slumps &turbidites

coquina shoal

oolitic megaripplesoolitic megaripplespatch reef hummocky units

Siliciclastic Dominated Systems

Carbonate Dominated Systems

L.S.F 1991

L.S.F 1991 24

Interpreta@on of Sandstones

Textbook Figure 13.9c

Fluvial Channel

Beach

Alluvial Fan

Fluvial Overbank

Eolian Dune

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hOp://en.wikipedia.org/wiki/File:CoralPinkSandDunesSand.JPG hOp://en.wikipedia.org/wiki/File:Morocco_Africa_Flickr_Rosino_December_2005_84514010.jpg

IronPellicles(rims)

FrostedGrains

EXAMPLE:AeolianDesertSandsSupermaturesandstone–QuratzAreniteDepositedinsandsheets,dunesandripples

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The QFL DistributionOf Sedimentary Rocks

In Various Tectonic Regimes

VOLCANIC ISLAND ARC

RECYCLED OROGENContinent-continent collision, orContinent-volcanic arc collision

BLOCK FAULTED CONTINENTAL BASEMENT

(including continental rift systems

STABLE CONTINENTAL CRATON

SandstonesProvenance(origin)andTectonicRegime-  QFLpropor9onsINGENERALcanbeindica9veofvarioustectonic

environments

CanyouexplaintheQFLfieldforthevolcanicislandarc?Seethetextbookreadings27

Mudrocks-  45–55%ofallsedimentaryrocksequences-  Mudrocks=Par9cles<65microns–4

microns(teethtest)-  Claygradeonly(<65microns)=claystone-  Siltgradeonly=siltstone

-  Shale=mudrockwithfissility

Textures-  Nottoomanyforfinermudrocks,siltgrade

mayshowmanyofthestructuresassociatedwithsandstones

-  i.Lamina9ons:parallellayering(<1cm)withinabed-varia9oningrainsizeand/orcomposi9on/oxida9onstate

-  ii.Mudcracks(seepreviouslecture)

hOp://www.neb.gc.ca/clf-nsi/rnrgynfmtn/nrgyrprt/ntrlgs/prmrndrstndngshlgs2009/prmrndrstndngshlgs2009-eng.html

U9caShaleQuebec(thewhitebedsare

limestones)

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-  iii.Fissility-  Beforecompac9on,contains

80%porespace

-  Thefissilityisduetosplivngbetweenparallelclayflakes

hOp://en.wikipedia.org/wiki/File:MesselShaleSplivng.JPG

wetsediment:mud compactedsediment shale–asercementa9on

WaterLoss

WaterLoss

splivngsurfaces

weightofnewsediment

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Colouri.  Grey-black

-Black=>1%carbonaceousmaterialand/orfinegrainedpyrite:generallyindicatedlowoxygencondi9ons–permitsforma9onofFeS2

-Anoxiccondi9onsrequirehigherinputoforganicsrela9vetoavailableoxygen…commonlylowenergy/quietcondi9ons

hOp://en.wikipedia.org/wiki/File:Cypresses.jpg

ASwamp-ONEexamplewhereblackshalesmayaccumulate–suggestothers

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ii.  Red-brown-yellow-green-  Presenceorabsenceof…..

-  FerricOxide(red)–Hema9te:Fe2O3onlyneedsfew%fordeepred-  FerricHydroxide(brown)–Geothite:[FeO(OH)]-  Limonite(yellow)-  Ifalltheaboveareabsent(green)reflec9ngcolourofmostsheetsilicates

-  GreenReduc9onspots/horizons:commoninredmudrocks…reflec9ngreduc9onofferricironadjacenttoplantrootorotherorganicmaterial

-  Greenlenses……possiblyshalloworganicrichponds?

hOp://www.soton.ac.uk/~imw/jpg-Budleigh-Salterton/6BS-ramifying-reduc9on.jpg

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BASIN

SUBMARINE FAN

SUBMARINE FAN

BASIN

Reef

OffshoreCarbonates


MEANDERING RIVER

BEAC

H

DELTA

shoreline sands

hummockybeds

tidalsandbars

SHELF

Lago

on

barrierisland

Tidal fla

t

Salt panDesertdunes

A LONGSYSTEM

A SHORTSYSTEM

Not to scale

Not to scale


BASIN


LAGOONTIDAL FLAT



salt pan

algallaminates

mudcracks

tidal channels

tidal sand bar

slumps &turbidites

coquina shoal




L.S.F 1991

L.S.F 1991

MineralComposiFon-  Claymineralsmostimportantgroup:mostlyillite,smec9te,kaolinite.

MudrocksdeposiFonalEnvironments-  Majorityofsiltandmudgradematerialfromerosionoflandmasses

-  Deposi9oninrela9velyquietenvironmentsbywater/wind

-  MARINEMUDROCKS

-  Marineshelf–typicallygrey,bioturbated.Osenpasslaterallyandver9callyinsanstonesand/orlimestones

hOp://en.wikipedia.org/wiki/File:ThalassinoidesIsrael.JPG

Bioturbatedsediment

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-  Nearshore-Example9dalflats/lagoons

-  Osendarkgreyreflec9nghighorganicinput

-  Iden9fiedbyflora/fauna/mudcracks

-  Osenassociatedwithcoarseclas9csrepresen9ngbeach/riverchanneldeposits

-  Brackish/hypersalinecondi9onsmaybepresent(restrictsfossildiversity)


BASIN

SUBMARINE FAN

SUBMARINE FAN

BASIN

Reef

OffshoreCarbonates


MEANDERING RIVER

BEAC

H

DELTA

shoreline sands

hummockybeds

tidalsandbars

SHELF

Lago

on

barrierisland

Tidal fla

t

Salt panDesertdunes

A LONGSYSTEM

A SHORTSYSTEM

Not to scale

Not to scale


BASIN


LAGOONTIDAL FLAT



salt pan

algallaminates

mudcracks

tidal channels

tidal sand bar

slumps &turbidites

coquina shoal




L.S.F 1991

L.S.F 1991

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-  Hemipelagicmudrocks–Deep/distantmarinesevngs

-  Osendarkgreybutcanbeavarietyofcolours

-  Redclayspresentinverydistantmarinesevngs:windblowndust

-  Commonlyassociatedwithpelagicfossils.Example:graptolitesinthelowerpaleozoic


BASIN

SUBMARINE FAN

SUBMARINE FAN

BASIN

Reef

OffshoreCarbonates


MEANDERING RIVER

BEAC

H

DELTA

shoreline sands

hummockybeds

tidalsandbars

SHELF

Lago

on

barrierisland

Tidal fla

t

Salt panDesertdunes

A LONGSYSTEM

A SHORTSYSTEM

Not to scale

Not to scale


BASIN


LAGOONTIDAL FLAT



salt pan

algallaminates

mudcracks

tidal channels

tidal sand bar

slumps &turbidites

coquina shoal




L.S.F 1991

L.S.F 1991

hOp://www.dec.ny.gov/permits/55748.html

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-  NON-MARINEMUDROCKS

-  AlluvialFloodplain(includingdeltas)–Overbankdeposits.Inaridclimatesareosenred,mudcrackedandcontaincalcareousnodules(calcretesorcaliche)


BASIN

SUBMARINE FAN

SUBMARINE FAN

BASIN

Reef

OffshoreCarbonates


MEANDERING RIVER

BEAC

H

DELTA

shoreline sands

hummockybeds

tidalsandbars

SHELF

Lago

on

barrierisland

Tidal fla

t

Salt panDesertdunes

A LONGSYSTEM

A SHORTSYSTEM

Not to scale

Not to scale


BASIN


LAGOONTIDAL FLAT



salt pan

algallaminates

mudcracks

tidal channels

tidal sand bar

slumps &turbidites

coquina shoal




L.S.F 1991

L.S.F 1991

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-  Lakes–mudrocksvaryconsiderablydependingonchemistryoflakewater/climate/organicproduc9vity

-  Rhythmicsedimenta9oncommoninlacustrinedeposits-  Nonglaciallakes-seasonalvaria9oninphytoplanktonproduc9vity

(mmscalelamina9on)–mayformoilshales-  Glaciallakes:varves

-  Coarse(silttofinesand)depositedduringspringmel9ng-  Finelamina9onsdepositedfromsuspensionduringsummer(includingorgainc

material)

hYp://en.wikipedia.org/wiki/File:GLMsed.jpg36

ORGANICRICHMUDROCKS

-  Typically3–10%organicmaOer

-  IncreasingorganicmaOerorganicrichmudrockspassintooilshales

-  SulfidicBlackShales

-  Abundantorganicmaterialandpyrite

-  Representdeposi9oninrestricted-circula9onanoxicmarinebasins

-  ClassicExample:TheBlackSea.

hOp://upload.wikimedia.org/wikipedia/commons/0/0d/The_Danube_Spills_into_the_Black_Sea.jpg

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-  Sulfateinporewatersisreducedtosulfidebyanaerobicbacteria

-  H2Sisproduced,reactswithFe2+producing(ul9mately)pyrite(FeS2)

-  Thisonlyoccursinverynearsurfacesedimentandonlyinareasofslowsedimenta9onrate.

hOp://en.wikipedia.org/wiki/File:Dvulgaris_micrograph.JPG

Desulfovibriovulgaris

0.5microns

Sulfate reduced by sulfate reducing

bacteria

REDUCTION

Sulfate (SO42-)

Sulfide (H2S)

Anaerobic sulfateReducing bacteria

Reaction H2S with Fe2+ or reactive Fe-mineral 4Fe2O3+9H2S ->8FeS+SO4

2-+8H2O+2H+

Reaction of iron sulfide with elemental sulfur FeS + S0 -> FeS2

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LowEnergy

Terrestrial

Lakes

Floodplains

Deltas

Marine

Lagoons

DeepWater

Belowwavebase

ENVIRONMENTSOFMUDROCKDEPOISTION:SUMMARY

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OTHERMUDROCKS-  Volcanicashfalls:bentonites-  Alteredvolcanicdebris(ash/tuff):mostlysmec9teandsilica-  Generally<50cmthick–thicknessofbentonitedecreasesawayfrom

volcaniccentre

Plumefromerup9onofChaitenvolcano,Chile

hOp://en.wikipedia.org/wiki/File:Plume_from_erup9on_of_Chaiten_volcano,_Chile.jpg

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-  LoessDeposits

-  Yellow–buffmostlysiltgrade20–50micronswiindblownmaterial

-  Verywellsorted–usuallyunstra9fied

LoessnearHunyuan,Shanxiprovince,China.Loesscanbeupto100mthick.Peoplewherehavecarveddwellingsoutofthesossediments

hOp://en.wikipedia.org/wiki/File:Loess_landscape_china.jpg

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GLOSSARY All lecture material is potentially examinable. Is up to you to know unfamiliar terms / names / people. Use this space to create your own lecture glossary

TERMS / NAMES DEFINITION

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TERMS / NAMES DEFINITION

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eosc221 - university of british columbia · eosc221 clastic (terrigenous / siliciclas9c)...

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