the far north mapping initiative: update and future plans
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The Far North Mapping Initiative: update and future plans
The Far North Mapping Initiative: The Far North Mapping Initiative: update and future plansupdate and future plans
Scott Anderson and Christian BöhmManitoba Geological Survey
Scott Anderson and Christian BöhmManitoba Geological Survey
Manitoba Mining and Minerals Convention 2008Researching Manitoba’s Exploration Frontier
The Far North Mapping Initiative….
• Major new MGS geoscience initiativefocused on Manitoba’s Far North(north of 58o north latitude)
• Manitoba Government commitment:$1.5 million over three years
• Matching funds from the GSC underthe federal government’s Geomappingfor Energy and Minerals (GEM) program
Objectives:• mapping to update 30+ year old
geological database• up-to-date assessment of mineral potential
Program commenced in fiscal 2008/2009:• GSC airborne magnetic and radiometric survey• MGS reconnaissance mapping and sampling
Major mapping programs planned for 2009, 2010
Aboriginal Community OutreachAboriginal Community Outreach
CommunicationCommunicationEducationEducationTrainingTrainingField work employmentField work employment
Regional settingRegional settingManitobaManitoba’’s far north*s far north*
• SE margin of Hearne craton• six geological domains• distinguished by:
cover rock-typesbasementstructural trendsmetamorphic grade
After:Weber et al., 1975Schledewitz, 1986
(*north of 58o north lat.)
Previous work
1935: GSC route survey of Seal River (Johnston, 1935)1953: Mines Branch recon.; Caribou and Wolverine rivers (Russell, 1953)1955: Mines Branch recon.; Seal River (Milligan, 1955)1953-1957: Earliest recorded exploration; Great Island1957-1962: GSC mapping; Kasmere, Munroe, Shethanei, Tadoule lakes1971-1972: MGS Kasmere project (Weber et al., 1975)1974-1978: MGS Cochrane and Seal rivers project (Schledewitz, 1986)1975-1976: Federal-provincial URP (airborne gamma-ray spectrometric and
lake-sediment surveys)1977-1980: GSC surficial geology and till sampling1970’s: Base metal exploration; Seal River-Great IslandLate 70’s: Uranium exploration; mainly Wollaston DomainLate 80’s: Gold and base metal exploration; Great Island Domain
Exploration Potential ofManitoba’s far north
Exploration Potential ofExploration Potential ofManitobaManitoba’’s far norths far north
Demonstrated potential for:• Volcanic-hosted
Cu-Pb-Zn-Au-Ag (VMS)• Orogenic Au• Alaskite U• Paleoplacer Au-U
Conceptual potential for:• Metasomatic/skarn REE-U-Au• Magmatic Ni-Cu-PGE• Iron-oxide Cu-U-Au (IOCG)• Sediment-hosted Pb-Zn-Ag (SEDEX)• Unconformity U• Diamondiferous kimberlite• Carbonatite Nb-P-REE
• Geoscience studies of the 1970s indicated the diverse geology andprotracted tectonic evolution of Manitoba’s far north
• Mineral exploration indicated diverse economic potential
• Exploration hindered byextensive surficial cover
• Indirect detection methods(e.g., till geochemistry, geophysics)
Recent MGS activities inManitoba’s far north: 2004-2006
2004200420062006
20052005
Rationale:• mitigate exploration risk by providing state-of-the-art geoscientific data• study poorly understood SE margin of the Hearne craton• further understanding of its nature, evolution and mineral potential
Methodology:• select remapping (1:50 000)• sampling of key rock-types(esp. supracrustal rocks)
lithogeochemistrySm-Nd isotope chemistryU-Pb zircon geochronology
• detailed till geochemical surveys• modest project budgets!
Objective:• updated regional bedrock and surficial
geological context
20042004
2004 program:Sm-Nd isotope analysis on archivalsamples from the Nejanilini Domain
2004 program:Sm-Nd isotope analysis on archivalsamples from the Nejanilini Domain
• granitoid intrusive rocks (9 spls.)• probable Archean age
(Schledewitz, 1986)• Nd model ages 3.2-3.0 Ga• εNd values 0.3 to -2.7• Hearne craton margin
Enderbite gneissNejanilini LakeEnderbite gneissNejanilini Lake
20042004
Future plans
2000 2200 2400 2600 2800 3000 3200 3400 3600
Rel
ativ
e pr
obab
ility
Lovat Lake quartz areniteLA-MC-ICPMS U-Pb zircon
2000 2200 2400 2600 2800 3000 3200 3400 3600
207Pb/206Pb age (Ma)
Rel
ativ
e pr
obab
ility
Churchill quartz areniteLA-MC-ICPMS U-Pb zircon
2568±3
~2720
~2570
2004 program:U-Pb geochronology on
detrital zircons inquartz arenites
2004 program:U-Pb geochronology on
detrital zircons inquartz arenites
Lovat LakeLovat Lake
ChurchillChurchill
~2720Lovat LakeQuartziteLovat LakeQuartzite
ChurchillQuartziteChurchillQuartziteCollected 2003
(R. Syme)
Hearne cratonsource
20042004
20052005
2005 program:Nejanilini Lake mapping
2005 program:Nejanilini Lake mapping
• three week field program• 1:50 000 bedrock mapping of
shoreline outcrops• lithogeochemical and
geochronological sampling• surficial mapping and till sampling
Nejanilini granulite domain: Hearne craton
Nejanilini Lake bedrock geology PMAP2005Nejanilini Lake bedrock geology PMAP2005--33
Quartzite
Semipeliticparagneiss
Biotiteenderbite
Biotiteenderbite
Kf-porph.granite
Biotitegranite
Deformed melt pod in paragneiss
2.70 Ga intrusive1.81 Ga metam.
2.56 Ga intrusive1.81 Ga metam.
2005 program:Nejanilini Lake mapping
2005 program:Nejanilini Lake mapping
1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400
207Pb/206Pb age (Ma)
Rel
ativ
e pr
obab
ility
96-05-2013QuartziteNejanilini LakeLA-MC-ICPMS U-Pb zircon
1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400
97-05-1003Semipelitic metagreywackeNejanilini LakeLA-MC-ICPMS U-Pb zircon
96-05-2013Nejanilini LakeQuartzite
97-05-1003Nejanilini LakeGreywacke
2005 program2005 programanalytical results:analytical results:
NejaniliniNejanilini Lake samplesLake samplesdetritaldetrital zircon age datazircon age data
(LA(LA--MCMC--ICPMS)ICPMS)
Rel
ativ
e Pr
obab
ility
Rel
ativ
e Pr
obab
ility
Vastly different sources ofdetritus
1) Two distinct cover sequences?(contact relationship?)
2) Single <1.9 Ga coversequence, with distinct sourceareas?
3) Single protracted (<2.7 to <1.9Ga cover sequence?
Mainly 1.9 Gadetritus
Mainly 2.7 Gadetritus
2004200420062006
20052005
2006 program:Kasmere and Putahow lakes mapping
2006 program:Kasmere and Putahow lakes mapping
• four week field program• 1:50 000 bedrock mapping of
shoreline outcrops• lithogeochemical and
geochronological sampling• surficial mapping and till sampling
Wollaston domain: Hearne craton margin
KasmereKasmere L.L.
PutahowPutahow L.L.
Snyder Lake
Kasmere Lake
Tice Lake
Putahow LakeS
a s k
a t c
h e w
a n
N u n a v u t
2006 program2006 programAnalytical results:Analytical results:
KasmereKasmere and and PutahowPutahow samplessamplesdetritaldetrital zircon age datazircon age data
(LA(LA--MCMC--ICPMS)ICPMS)
1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400
207Pb/206Pb age (Ma)
Rel
ativ
e pr
obab
ility
~ 2.71700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400
Rel
ativ
e pr
obab
ility
~ 2.0
~ 2.6~ 2.7 96-06-816-1
Putahow LakeGreywacke
96-06-782-1Kasmere LakeQuartzite
1) Two distinct cover sequences?(depositional or tectoniccontact relationship?)
2) Single <1.9 Ga coversequence, with distinct sourceareas?
3) Single protracted (<2.7 to <1.9Ga cover sequence?
• diverse supracrustal rock-types• better exposure (but not great!)• less deformed• lower metamorphic grade
The Far North Mapping Initiative• designed to address outstanding questions regarding
the geological evolution and mineral potential ofManitoba’s far north
• initial focus on Great Island Domain
Great Island domain
94°
96°
96°
98°
98°
60° 60°
59° 59°
58° 58°
25
Kilometres
949698
25
Kilometres
NLNL
GBGBGIGI
• Supracrustal rocks disposed insynformal basins
• Include only known exposures ofvolcanic rocks in Manitoba’s farnorth (age and significance?)
• Basins clearly delineated byregional aeromagnetic surveydata, include:
• Great Island• Grand Bend• Nowell Lake
• Evidence of regionalunconformities separatingmetasediments from underlyingmetavolcanic rocks
The Far NorthMapping Initiative:
Great Island Domain
The Far NorthMapping Initiative:
Great Island Domain
Archean greenstone belts?
The Far NorthMapping Initiative:
2008 program
The Far NorthMapping Initiative:
2008 program
2008
2008
• two week field program• reconnaissance mapping and sampling• mobe/demobe from Churchill• helicopter-supported from Sosnowski Lake
ChurchillChurchill
Sosnowski LakeSosnowski Lake
Dymond LakeAir Services Ltd.Dymond LakeAir Services Ltd.
Custom Helicopters Ltd.Custom Helicopters Ltd.
Sosnowski Lake campSosnowski Lake camp
• visited 43 localities over four days• collected representative suite of 49 samples:
all the major rock-types, bedrock and drillcore• samples suitable for lithogeochemistry, Sm-Nd
isotope analysis and U-Pb geochronologyEppler LakeProject (active)Eppler LakeProject (active)
Polar GoldProject (1988)Polar GoldProject (1988)
The Far NorthMapping Initiative:
2008 program
Enderbite gneissNejanilini DomainEnderbite gneissNejanilini Domain
Complex orthogneissComplex orthogneiss
PeridotitePeridotite
Granodiorite gneissGranodiorite gneiss
Porphyritic granitePorphyritic granite
Intrusive rocks:Intrusive rocks:ArcheanArchean andandPaleoproterozoicPaleoproterozoic
The Far NorthMapping Initiative:
2008 program
Volcanic, volcaniclastic andderived sedimentary rocks: Archean?Volcanic, Volcanic, volcaniclasticvolcaniclastic andandderived sedimentary rocks: derived sedimentary rocks: ArcheanArchean??
Aphyric rhyolitebrecciaAphyric rhyolitebreccia
Felsic lapilli tuffFelsic lapilli tuff
Pillowed basalt/andesitePillowed basalt/andesite
Mafic volcanicconglomerateMafic volcanicconglomerate
PolymicticconglomeratePolymicticconglomerate
Classical Archeangreenstone belt sequence?
The Far NorthMapping Initiative:
2008 program
Flat-lying, planar-bedded quartziteFlat-lying, planar-bedded quartzite
Paleoproterozoic cover sequence:• basal quartzite-argillite; fluvial to shallow-marine
• upper greywacke-argillite-marble;basinal marine
PaleoproterozoicPaleoproterozoic cover sequence:cover sequence:•• basal quartzitebasal quartzite--argillite; argillite; fluvial to shallowfluvial to shallow--marinemarine
•• upper greywackeupper greywacke--argilliteargillite--marble;marble;basinalbasinal marinemarine
The Far North Mapping Initiative:2008 program
FerruginousargilliteFerruginousargillite
Ball-structures ingreywacke-mudstoneturbidites
Ball-structures ingreywacke-mudstoneturbidites
Dolomitic marbleDolomitic marble
AmygdaloidalbasaltAmygdaloidalbasalt
SulphidicargilliteSulphidicargillite
GreywackeGreywacke
AreniteArenite
North Knife RiverNorth Knife River
Paleoproterozoic cover sequence:• includes both basal and upper sections• amygdaloidal basalt flow(s)• basinal marine setting
PaleoproterozoicPaleoproterozoic cover sequence:cover sequence:•• includes both basal and upper sectionsincludes both basal and upper sections•• amygdaloidal basalt amygdaloidal basalt flow(sflow(s))•• basinalbasinal marine settingmarine setting
BaseBase--metalmetalpotential?potential?
Monroe LakeMassive arkoseMassive arkose
Trench on pegmatiticalaskiteTrench on pegmatiticalaskite
Fracture-controlleduranophaneFracture-controlleduranophane
Pegmatitic alaskitePegmatitic alaskite
• Monroe Lake synform• Arkose intruded by
pegmatitic alaskites• U occurrences
The Far NorthMapping Initiative:
2008 program
• Samples submitted to GSC geochronology labs• U-Pb zircon age dating:
• Isotope-Dilution Thermal-Ionization Mass Spectrometry (ID-TIMS)• Sensitive High Resolution Ion MicroProbe (SHRIMP)
• Age data to provide geochronologic context
http://gsc.nrcan.gc.ca/labs/geochron/shrimp/index_e.php
The Far NorthMapping Initiative:
2008 program
94°
94°
96°
96°
98°
98°
59°
58°
GSC-funded High Sensitivity AirborneGeophysical Survey
GSC-funded High Sensitivity AirborneGeophysical Survey
Survey specs: • Flown fall 2008• Magnetic total field• Gamma-ray spectrometric• ~17,000 line-kilometres• 125 m nominal terrain clearance• 400 m line spacing (current 5 km)
Processed variables:• Natural air absorbed dose rate• Potassium (%)• Uranium (ppm)• Thorium (ppm)• Uranium / Thorium• Uranium / Potassium• Thorium / Potassium• Residual total magnetic field data• First vertical derivative of the
magnetic field data• Digital elevation model data
The Far NorthMapping Initiative:
2008 program
ChurchillChurchillChurchill
Sosnowski LakeSosnowskiSosnowski LakeLake
• data collected in 2008 will providefoundation for 2009 mapping project
• planned to include:• Great Island• lower Seal River• lower North Knife River
• six to eight week field program• based out of Sosnowski Lake camp• helicopter supported
The Far North Mapping Initiative: Plans for 2009The Far North Mapping Initiative: Plans for 2009
Objective:• updated geological map of
Great Island area•Tectonostratigraphy of
supracrustal sequences• assessment of mineral potential
VMS
Au-UAlaskite U
Unconformity U
Diamondiferous kimberlite
SEDEX
IOCG
Magmatic Ni-Cu-PGE
REE-U-Au
Orogenic Au
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