outline study areas - university of ottawa

March 2005 1

The Lac des Iles palladium deposit: The Lac des Iles palladium deposit: mineralization within the South mineralization within the South Roby, Twilight, and High Grade Roby, Twilight, and High Grade

Zones.Zones.

A summary of research progressA summary of research progress

John Hinchey & Keiko HattoriJohn Hinchey & Keiko HattoriUniversity of OttawaUniversity of Ottawa

OutlineOutlinePGE mineralization at the Southern Roby PGE mineralization at the Southern Roby and Twilight Zones. and Twilight Zones.

Characteristics of the High Grade Zone. Characteristics of the High Grade Zone.

Current Studies: Current Studies: PetrogenesisPetrogenesis of the SRZ, TZ, and HGZ. of the SRZ, TZ, and HGZ. Base and precious metal Base and precious metal ccnsccns of of sulphidessulphidesfrom each zonefrom each zone

Regional GeologyRegional GeologyProterozoic

Diabase

ArcheanLate Granitoids

Bt-granodiorite/graniteBt-hbl ton./granodiorite

Late Mafic/UltramaficsUltramaficsGab./gabnorHbl gab., hornblenditeHornblende diorite

Early GranitoidsFol./gneissic bt ton.

Supracrustal RocksMafic metavolcanicsMetaseds

FaultPGE occurrence

Modified after Sutcliffe and Smith, 1988

QueticoSubprovince

Lac Des Iles

Tib Gabbro

Dog River Intrusion

Taman LakeIntrusion

Demars LakeIntrusion

Legris LakeIntrusion

Roby Zone

Lac Des IlesComplex

Buck LakeIntrusion

0 5 10Kilometres

Study AreasStudy Areas

Modifed after Sutcliffe and Sweeney, 1986

Hbl. Gabbro

Lac Des Iles

Camp Lake

Roby Zone Twilight

Zone

BakerZone

CreekZone

100 MetresGabbronorite

High Grade Ore

Varitextured gabbroEast GabbroGranitesDiabase

Pyroxenite

March 2005 2

104285N

1051

90E

104080N

1054

10E

Mineralizing melanocratic phases

Mesogabbro

Clinopyroxenite

Dark gabbro

10 m

SouthernRobyZone

Post-mineralizationmelanocratic phases

Medium-grained, medium-green clinopyroxenite

(Hinchey et al., 2003, 2005)

Late melanocratic magma brought PGELate melanocratic magma brought PGE

MgabGab

1.81 g/t Pd

0.042 g/t Pd

ClinopyroxeniteClinopyroxenite

Cpxinite

Gabbro0.19 g/t Pd

5.2 g/t Pd

Late Dark Gabbro is mineralizedLate Dark Gabbro is mineralized

Gabbro

12.5 g/t Pd

9.2 g/t Pd

0.04 g/t Pd

Gabbro

March 2005 3

Twilight ZoneTwilight Zone(Hinchey et al., 2003, 2005)

Granitic DykesPegmatoidsMgab/cpxiniteAnorthositeM.g. Lgab

M.g.gabMicrogabGabnorNorite brecciamnor breccia ***Gab/gabnor breccia~~~ Faults

Mineralized Mineralized MelanonoriteMelanonorite

Mineralizedmelano-norite

Norite

3.0 g/t Pd

0.08 g/t Pd

Sulfide/Silicate at SRZ and TZSulfide/Silicate at SRZ and TZ

Opx

Opx

Opx

Plag

Po,Pn,Cpy

Ser

Po,Pn,Cpy

Ser

Act

Act

Act

Chl

1 mm

1 mm

Hbl

0.5 mm

Pn

Ccp

PoAct

Ccp

0.2 mm

Act

(Hinchey et al., 2005a; Hinchey & Hattori, 2005)

Characteristics of fertile magmaCharacteristics of fertile magma

Fertile magmas are distinctly different from barren magmas

Hinchey et al., 2005a

1

10

Ce Pr Nd Sm Eu Gd Dy Ho Er Yb

Rock

/Cho

ndrit

es

Fertile melanocraticMagmas

Barren clinopyroxenite

March 2005 4

PGE MineralizationPGE Mineralization

Distribution of the PGEDistribution of the PGEIdentify fertile units.Identify fertile units.

Control of mineralizationControl of mineralizationMagmatic Magmatic sulphidesulphide liquid vs. secondary liquid vs. secondary hydrothermal enrichment.hydrothermal enrichment.Proposed model of formation.Proposed model of formation.

Melanocratic magmas brought PGEMelanocratic magmas brought PGE

Hinchey et al., 2005a0 10 20

0

10

20

Pd (p

pm)

MgO (Wt. %)

0

1

2

Pt (p

pm)

MelanocraticLeucocratic

SRZ melanocratic unitsSRZ early Leucocratic unitsTZ melanonoritic unitsTZ noritic/lnor unitsTZ melanogabbro/cpxinite units

Magmatic mineralization of PGEMagmatic mineralization of PGE

0 1 20

5

10

15

20

25

Pd (p

pm)

S (Wt. %)

r=.895

SRZTZ

PGE ConcentrationsPGE Concentrations

1

102

104

106

Ni Os Ir Ru Rh Pt Pd Au Cu

Roc

k/P

rimiti

ve M

antle

Southern Roby zoneTwilight zoneHigh Grade zone

March 2005 5

Leucocratic magma lost Leucocratic magma lost sulphidessulphides

1 10 102 103 104 10510

102

103

104

Cu/

Pd

Pd (ppb)

Man

tle

J-M

UG

Sud

N

Melanocratic

LeucocraticFPMR

Proposed model of mineralization for the Proposed model of mineralization for the SRZ and TZ.SRZ and TZ.

Bulk of the PGE were introduced by late, fertile, Bulk of the PGE were introduced by late, fertile, melanocratic magmas.melanocratic magmas.Fertile magmas show distinct chemical Fertile magmas show distinct chemical compositionscompositionsCorrelations between S and PGE suggests Correlations between S and PGE suggests magmatic mineralization. magmatic mineralization.

This is supported by This is supported by sulphidesulphide texturestextures

Fractional crystallization resulted in high Fractional crystallization resulted in high PPGE/IPGEPPGE/IPGE

Mineralization process: Part 1Mineralization process: Part 1

sulphides

Mineralization Process: Part 2Mineralization Process: Part 2

incorporation of existing sulphides

March 2005 6

High Grade Ore ZoneHigh Grade Ore Zone

SulphideSulphide and silicate mineralogyand silicate mineralogy

Geochemical characteristicsGeochemical characteristics

Proposed model of formationProposed model of formation

Chlorite + Actinolite

Blue Qtz

High Grade Ore ZoneHigh Grade Ore Zone

Py

QtzQtz

High Grade ZoneHigh Grade Zone

Mi

Sieg

Act

Qtz+Chl+Act+Hbl

Qtz

PoPn

Py

Chl

ActChl+Act+Qtz

Py Chl

Act

Chl

1 mm

Hbl

Hbl

Qtz

Qtz

Mi,Sieg,Cpy

1 mm

Mil

QtzAssemblage 1

milleritesiegenitechalcopyrite

Assemblage 2

pyritechalcopyrite

Palladium, Pt, S were mobilePalladium, Pt, S were mobile

0

20

Se(p

pm)

r=0.815

1 20

1

2

S(W

t.%

)

Pt (ppm)

r=0.759

0

20

Se(p

pm)

r=0.952

0 2000 40000

1

2

S(W

t.%)

Ni (ppm)

r=0.769

~ ~8000

~ ~

SRZ & TZ

SRZ & TZ

SRZ & TZ

SRZ & TZ

High Grade Zone

March 2005 7

Bleached East Gabbro at the Contact with the High Grade Zone

Typical East Gabbro

BleachedEast Gabbrowith moderatePd

HGZ

Pegmatite associated with melanocratic Pegmatite associated with melanocratic magmasmagmas

Pl+CpxPl+Cpx

Coarse grained sulphide (pyrrhotite and chalcopyrite) associated with a pegmatitic vein: main Roby Pit

Summary of the HGZ OreSummary of the HGZ OreIntense alteration and lowIntense alteration and low--temperature temperature sulphidesulphideand silicate assemblages.and silicate assemblages.

Palladium, Pt, Cu, S were mobile.Palladium, Pt, Cu, S were mobile.

The original magmatic mineralization (8The original magmatic mineralization (8--21 21 ppmppmPd) was upgraded during hydrothermal activity.Pd) was upgraded during hydrothermal activity.

Fluids from fertile mafic magmas were Fluids from fertile mafic magmas were responsible for the upgrade.responsible for the upgrade.

March 2005 8

Current StudiesCurrent Studies

The The petrogenesispetrogenesis of the mineralized rocks.of the mineralized rocks.

Possible investigation of PGE contents in Possible investigation of PGE contents in various various sulphidessulphides