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

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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

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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