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F.F.- BONAVIA - The geology and geochemistry of Radiore 2 mine, Matagami, Quebec.

.-- Department of Geological Sciences - Master of Science.

ABSTRACT

The Radiore 2 mine is a "Noranda-type" volcanogenic exalative

massive sulphide deposit associated with a tholeiitic metabasalt -

metarhyolite bimodal suite.

Core Iogging and compilation of lU1derground mine maps led to the

interpretation that basic and acid submarine volcanism was followed by

a progressive hydrotherrnal alteration I,ll1d ore deposition. Multiple sills

and dykes were ernplaced. Following the main period of folding, a regional

metamorphism te the lower amphibolite facies was superimposed.

Three main alteration assemblages have been recognized:

1) spilitization, the mast carumon alteration; 2) potassium metasomatism,

formed in the low temperature end of the geothermal system;

, 3) chloritization, forrned in the high temperature fluid circulation zone.

From the bulk composition of the massive sulphide ore, specific

groups of elements (Cu-Zn-Cd-Au), (Ag-Pb-As-Sn-Bi), (Mo-W-Co) and

(Cr-Ni-V-Mn) have similar enrichment factors (ratio of element content

lof the massive ore/unaltered rocks). ) . ,

The process of ore generation (Cu and Zn) is seen as a simple

series of irreversible chemical reactions in a geothermal 'system where

Cu-Zn-Fe-Au-S were leached from the basic rocks and precipitated at the

discharge point to form Radiore 2. "

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F. F. BCNAVIA - La géologie et la géochimie de la mine Radiore 2, Matagami, Québec.

Département de Géologie - Maîtrise en Sciences.

SO!vMAlRE

Le gisement Radiore 2 de sulfures massifs, qu~ est de "type

Noranda" et donc provient d'exhalaisons volcanogé.niques, se situe dans

une séquence volcanique bimoda1 métabasalte - métarhyo1i te.

A la lumière d'une analyse détaillée de carottes et d'une

compilation cartographique de la mine, on propose une période de vol-

canisme sous-marin, basaltique (tholéiitique) et rhyoJitique, suivie

de manifestations hydroth~rmales. Plusieurs générations de sills ont

ensuite recoupé cette séquence. Les roches ont été métamorphisées

(facies amphibolite inférieur) pendant la période principale de

plissement.

On voit trois épisodes distin~ts d'altération: l)spilitisation,

l'association la plus répandue, 2) métasomatisme K, dans la portion

basse-température du système géothermique, et 3) chloritisation, dans

sa portion haute-température.

On peut grouper les éléments dans le minerai (Cu-Zn-C~-Au),

(Ag-Pb-As-Sn-Bi), (Mo-W-Co) et (Cr-Ni-V-Mn). Au sein d'un groupe,

chaque élément montre un facteur d'enrichissement de concentration ~

(minerai massif/roche saine) semblable.

La formation de sulfures de Cu et de ~n résulterait de réaètions

chimiques irréversibles; un lessivage des éléments Cu, Zn, Fe, Au et S

de la paroi inférieure et leur précipitation au point de décharge

seraient à l'origine du gisement Radiore 2.

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ACKNMEDGEMENf

1 wish to expres]3 my sincere gratitude to al! the people who

assisted me in this work. \

l am especially indebted ta Dr. W.H. MacLean, whose adylce

,pro~icled the inspiFation for this project.

l also thank Dr. A.E. Williams":'Jones who supplied helpful

critisisms and Dr. R. F. Martin for XRD analysis and for the

French translation of the abstract; Charles Be~udry for

discussions and for reading an early draft of the thesis. Noranda

Mines Ltd. for pennission to undertake this study and the assistance

of André Bonenfant, mine geologist of Radiore 2, is appreciated.

The technical assistance of Mr. R. Yates in prcparing the photographs

is acknowledged. Many thanks ta Reggie Rabbins who patiently typed

mnnerous drafts of this thesis.

Financial support at McGil1 University was provided by Carl

Beinhardt Summer Award, by the National Science and Engineering

Re se arch Council of Canada Grant 111\7719 and by the F.C.A.C. (Government

of Quebec) Grant #649 ,bath to W.H. MacLean.

Finally l wish ta thank Mr. Antons Mtmcs and bIS family whose

wann hospitality made pleasant my stay in Montreal.

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TABLE OF CONTENTS

INTRODUCTION' - GENERAL STATEMENT

ŒIAPTER 1

Object: of the Present Study

~thod of Study

- mE REGICNAL GEOLOGY AND MINING ACfIVITY AT RADIORE 2

1.1 The Regional Geology

1.2 Mining Activity at Radiore 2

œAPTER 2 - mE GEOLOGY AT RADIORE 2

2. 1 Introduction

2.2 Eruptive Sequences

2.3' Intrusive Rocks

2.4 Structure

2.5 Me t amorphi sm

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œAPTER 3 - PETROGRAPHY! ALTERATION AND METAMJRPHIEM

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2

3

6

8

10

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17

3.1 Introduction 18

3.2 Metavolcanic (Bla) 19

3.3 Radiore Rhvoli te (RR) 21

3.4 Metavolcanic (BIb) 22

3.5 Bell Channel Rhyolite (BeR) 24

3.6 Gabbro Dyke! Quartz Diori te Sill and Diabase Dyke 25

3.7 Gabbro-diorite Dyke 26

3.8 Rock Alteration 27

3.9 Relationships Between Alteration and Metamorp~ism 31

CHAPTER 4 - WALL-ROCK G'EOCHEHISTRY

4.1 Introduction

4.2 Geochemistg 0l. the ExtTIlsive Rocks

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4.3 Metavolcanics

4.4 Rhyolites

4.5 Geochemistry of Intrusive Rocks

4.6 Gabbro-Diorite Dyke

œAfYI'ER 5

5.1

5.2

5.3

5.4

5.5

5.6

ŒlAPTER 6

- PETROGRAPHY AND GEOCHEMI STRY OF TIΠOREBODY

Introduction

InternaI Structure of the Orebody

Ore and Gangue Mineralogy

to rocesses

Distribution of Elements in the Sulphide Ore

Metal Distribution

- SEAWATER/ROCK INTERACTION: .AN INTERPRETATION OF THE FORHATtON OF RADIORE 2 MASSIVE Stn:PHIDE DEPOSIT

6.1, Introduction

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58

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62

62

64

67

69

80

84

6.2 J:, :;,Discussion: Hydrothennal Alteration 85

6.3 Relationship Between Alteration and Ore Deposition 92

6.4 Reconstruction and Proposed Madel for Radiore 2 93

CONTRIBUTION 98

REFERENCES 99

APPENDIX l - $.AMPLE PREPARATION AND ANALYTlCAL PROCEIlJRE

1-1 Sampling

1-2 Sample Preparation

(1) General -(2) Fused Pellets for ;(RF Analysis (3) Powder Pellets for XRF AIlalysis

1-3 Loss on Ignition (LOI)

(1) LOI Analysis

1-4 X-Ray Fluorescence Analysis (Major

(a) Accuracy 0 f the XRF Anal ys is (b) PrecislOn of Sarnple Preparation

Elements)

109

109 110 110

110

112

112 113

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I-5 X-Ray Fluorescence Ana1ysis (Minor and Trace Elements) Ca) Cu, Zn, Ni, Mn, Cr Determination (b) Rb i Sr, Y, Zr, Nb Dëtennination Cc) Su phur Dëtennination

I-6 Externa1 Trace Element Ana1ysis

APPENDIX II - MEASURED BULK DENSI1Y FOR TI-IE EXTRUSlVE ROCKS D

APPENDIX III - MAJOR AND TRACE ELEMENT COMPOSITION OF THE VOtCANlc ROCKS

Ca) MAJOR ELH1ENT GEOCHEMISTRY (b) TRACE ELEHENf GEOCHEMISTRY Cc) COMPARISON OF MAJOR (Wf%) AND TRACE ELEMENf

CCNI'ENT (ppm) IN VOLCANIC ROCKS

APPENDIX IV - STATISTIC

APPENDIX V - RADIORE SAMPLES LISf

MAPS

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2

3

4

5

Surface Geology Geo1ogica1 Section: l-SOE Geological Sections: 1-95E and l-OSE

Mine Plans:

Ca) Ramp Cb) ~jtudinal Section Cc) Level No. 1 (d) Leve! No. 2 Geology of Level No. 1

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113 l15 115 119

123

125

126 132

~ 136

138

142

147

148

149 149 149 149

150

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Lt ST OF PLATES

1.1 Metavolcanic Bla; preserved sodic plagioclase

1.2 Metavolcanic Bla; chloritic alteration rim bordering biotite grain

1.3 Metavolcanic Bla; replacement of primary sodic fe1spar

1.4 Metavo1canic Bla; patch of poikilitic quartz

2.1 Metavolcanic B1a; poikilitic quartz grain containing relies of early alteration mineraIs

2.2 Radiore rhyolite; typical 'fragmentaI rhyolite

2.3 Radiore rhyolite; partly dissolved felspar grain in weIl oriented plat y mineraIs

2.4 Radiore rhyolite; iso1ated spherules showing original radiating structure

3.1 Radiore rhyolite; dissolved spherulitic grain with growth of pressure shadow mineraIs

3.2 Radlore rhyolite; perlitic texture

3.3 Radiore rhyolite; microvesicles within devitrified glass

3.4 Radiore rhyolite; vesicles filled by rnicrocrystalline quartz

4.1 Metavolcanie Blb; variably oriented amphiboles

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39

39

39

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40

40

40

41

41 41

41

42

4.2 Bell ~annel rhyolite; ovoid to subrounded vesicles texture 42

4.3 Bell Channel rhyolite; serrated boundaries and undulated extinction Of quartz in vesicle

4.4 Bell Channel rhyolite; magnetite grains rimming the edge of a vesicle

5.1 Bell Channel rhyolite; radiating spherules set in devitrified glass mesostasis

5.2 Bell Channel rhyolite; alpha quartz parambrphed of beta quartz

5.3 Bell Channel rhyolite; embayed relie of quartz showing resorbed features

5.4 Bell Channel rhyolite; quartz phenocrysts showing pressure shadows as a product of intergranular f1uids

6.1 Radiore Siliceous ore; siliceous massive sulphide (Basal Zone)

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6.2 Radiore Massive ore; ch10ritized fragments in banded

1 massive su1phide (Upper Zone) '82

6.3 Radiore Massive ore; cross-cutting re1ationship in

1 banded massive sulphide (Upper Zone) 82

6.4 Radiore Massive ore; monomineralic 1ayers in banded massive sulphide (Upper Zone) 82

7,1 Radiore Massive ore; porphyroblasts or pyrite 83

7.2 Radiore Massive ore; elongated curved grains of pyrrhotite 83

7.3 Radiore Massive ore; actinoli te crystals in massive chalcopyrite 83

7.4 Radiore Massive ore; euhedra1 amphiboles dispersed randomly in sphaleri te 83 If

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1.1

2.1

2.2

3.9

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

4.10

4.11

5.1

5.Z

5.3

6.1

6.Z

6.3

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LIS[ OF FIGURES

Regional and Local geology

Stratigraphie section through the Volcanic Rocks ,

Detailed geological description of UR-12 drill-,hole

T-XC02 diagram showing phase relations in the syst:em KzD:"CaO-MgO-Alz03-Si02-HZO-COZ at 5 kb

Wt % TiOZ vs Y/Nb plot of metavolcanic rocks

Jensen cation plot (Extrusive rocks)

Wt% AlZ03 vs An nonnative plagioclase composition ~

Nonnative colour index (CI) vs normative plagioclase composition

Wt% TiOz vs wt% MgO

SiOz (wt'a) vs major oxides (wt'a) of Bla and Blb

SiOz (wt'a) vs trace clements (ppm) of Bla and Blb

SiOz (wt %) vs maj or oxides Cwt %) of RR and BCR

Jensen cation plot (Intrusive rocks)

~ -RZ plot of plutonic rocks

SiOZ (wt%) vs major oxides (wt'a) of gabbro-diorite dykes

Histograms

Plots of good (Cd/Zn) and poor (Au/Ag, AulAs) c017elation coefficient f,)

Enrichment factors plot of sorne elements associated

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47

48

49

52 S~-

57 58

. 59

60

75

76

wi th the ore 79

Temperature vs pH plot, showing experimental and calculated curve of mineraI stabili ty 90

Temperature vs pH plot, chowing logarithmic-concentration of Au, Cu and Zn

Schernatic illustration of the geothennal system developed

93

below Radiore 2 deposit 94

6.4 Schernatic reconstruction of Radiore Z mine 96

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LIST OF TABLES

3.1 Sequence of Alteration Events 3.2 Selected Mineral Assemblages Found in the Altered

Metavolcanics 4. 1 of Metavolcanics

4.2 of Radiore RR)

'5.1 Trace Element Geochemistry of Ma.;sive Sulphide Ore (pPI11)

5.2 Mean Element COmposition in the Orebody and in Unaltered Rocks Together with the 'Enrichiiient Factor Composition

5.3a Elementary Statistics 5.3b Correlation Matrix

5.4 Comparison of Au, Zn, Cu, Ag Concentf~tion Obtainëd fTom this 'Study and fram the Mill-heads

5.5 Cu, Ni, Zn Concentration in the Least Altered and a Altered Rocks 1 and in the MassiVe<: Ore

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'. INTRODUCfICN

GENERAL SfATEMBIT

Hydrotherma1 alteration of oceanic basa1ts to the greenschist

facies by interaction wi th seawater has frequently p~'en encotmtered in

samp1es dredged from mid-ocean ridges (e.g., Melson et al., 1968; Shido

et al., 1974). Basa1t-seawatcr interaction has now been investigated

in experirnenta1 work (Bischoff and Dickson, , 1975; Hajash, 1977; Mottl

and Hol1and, 1978) confirming that this was the mechanism of a1teration.

The presence of metal1iferous sediments in the Red Se~ (Bischoff, 1969)

and at oceanic ridges (Bostrom et al., 1971), and the existence of

meta11iferous sediment mounds associated with active hydrotherma1 sy?tem

at the Ga1apagos spreading center (Cor1iss et al., 1977) and at the TAG

hydrothermal field (Lowe1 and Ronë, 1976) have been documented and _

confirm the re1ationship between hot brines and ore genesis. Hence'~'· the

occurrence of massive sulphide deposits associated with submarine volcanic

rocks has been used to infer that the minera1ization is the result of

convected seawater leaching metals from the basaltic crust Ce.g. Ohmoto

and Rye, 1974; Spooner, 1977; MacGeehan and MacLean, 1980b).

AlI this has convinced many geo10gists in the last twenty years

or 50 to develop new models in o~position to the epigenetic replacement

one, popu1ar among workers before the nineteen-sixties, that massive

sulphide deposits are related in tirne and space ta the valcanic rocks

and, more recently, that there is also a close genetic relationship

Ce.g., Constantinou and Govett, 1973; MacGeehan, 1978) between these

rocks and the ore mineralogy.

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If this model is correct it should be possible to find a relation

between the concentr~tion of th~ major and trace metals in orebodies and

voléanic rocks. This study will be deve10ped a10ng this 1ine of reasoning.

Object of the Present Study

The Abitibi project was set up at McGi11 University in 1974 with

the intention to study in great detail a part of the Archean Abitibi

greenstone belt and related ore deposits occurring at Matagami, Quebec.

The ,present study is part of this research and was initiated in January

1980.

The main puipose was to coriduct a geological and geochemical

investigation of Radiore 2 Mine. Radiore 2 was chosen because at this

tirne the mining operation was in full activity to exploit the orebody.

Hence the opportunity was use~ to obtain access to sorne part of the

massive ore and expedite underground geologica1 rnapping and sampling,

as part of the scope of the Abitibi Project is to collect and retrieve

basic data from the mines in the are as which otherwise would have been

lost.

The research was entirely devoted to the are body and ta the

vo1canic rocks stratigraphically 100 metres above and 250 metres below,

because of,constraints imposed ~y the lack of outcrops and the-lirnited

extent of stratigraphy investigated by drilling. A detailed surface

geology rnap (1 inch = 100 fe,et) was available fram the previous" regional

study by MacGeehan (1979); re-mapping around the mine was not considered

as it would have added little information for the present geological

interpretation.

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The maj~r objectives of this study are:

1) to briefly record the history of Radiore 2 and the mine operations. 1

2) to establish through detailed core-Iogging the mine stiatigraphy

from one of the more recent exploration drill-holes (UR-12), and

to re-log part of the old cores for correlation purposes in arder

to construct a geological map and cross-sections of the mine.

3) to study the petrography of the altered volcanic rocks arOl.md the

orebody and identify mineraI alteration assemblages.

4) to study the geochemistry (major and trace elements) of the

5)

6)

volcanic rocks and deterrndne the main geochemical changes ta

corroborate petrographie observations and mineraI assemblages.

to map in great detail (1:50) a section of the orebody to gain

insight into the mode of emplacement of the ore and the

distribution ûf'the metals.

to sample the massive sulphide ore and geochemically petermine

the range of concentration of trace elements within the orebody

to test the geothermal model for the genesis of the massive

sulphides.

7) t~ atternpt," in the light of what is already known and fraln new

studies of hydrothermal plumes in the Galapagos rift, an inter-

pretation of the genesis of Radiore 2 deposit.

Method of Study

The first phase of the study invol ved geological Înapping and

sampling of the backs of the drift on mine level No. I,logging diamond

drill core of surrounding rocks, and surface mapping where the orebody " .

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was exposed by mining activity. A preliminary investigation was made

during January 1980 and comp1eted during a portion of the same stmmer.

Thin-sections, polished thin-sections and polished sections were

made for study with the aid of the microscope and qualitative e1ectron

microprohe analyses. X-ray fluorescence analysis was used as the

analytical rnethod for the major and sorne of the trace elernents. Other

methods were emp10yed by outside laboratories ta treat the rest of the

trace elements.

A complete documentation of aIl methods and procedures used in

the present investigation is reported in the Appendix:

Appendix l

Appendix II ,

Appendix III;

Appendix IV

Appendix V

Sample preparation and analytical procedure.

Measured bulk density.

Major and trace element composition of rocks.

Statistics

Sample reference

the vo1canic

Ta aid in the reading and use of the text;

-Figures (Fig. x.y) and Tables (Table x.y) quoted in the study

are presented in the chapter marked by the letter x.

-Plates are placed at,the end of the chapter in which they are

referred.

-Maps are placed after the Appendix.

-The position of the sarnples quoted in the text can be fO\.md by

consulting Appendix V. 1

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-The sample used for the petrographic description of the alteration

assemblages does not always ~tcP by number with the sample used

ta determine the geochemistry; however" the two are closely

related in space. Reference can be found by consulting Appendix V.

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CHAPI'ER 1

1HE REGIOOAL GEOWGY AND 1l-IE MINING ACTIVITI AT RADIORE 2 , The Regional Geology

Radiore 2 is one of a series of massive sulphide deposits found

in one of the largest volcanic centres in the Abitibi greenstone belt

of the Superior Province (Goodwin and Ridler, 1970). It lies

approximately 750 km north of Montreal, Quebec (Fig. 1.1, inset map).

The first complete regional geological investigation was made by

Sharpe (1964, 1968). The area is largely covered by glacial deposits

which obscure most of the Arche an volcanic rocks. These range in

composition from basaIt to rhyolite and have been intruded by the Bell

River igneous complex, a layered mafic intrusion, and by many subsidiary

sills and dykes. The entire area was metamorphosed largely to the

greenschist facies and then folded into what has been interpreted as a

westward plunging anticlinal structure. In the northern limb the

" volcanic rocks strikes approximately east-west, faces north and dip

vertically, while a more gentle southerly dip is observed on the south

limb which has a northwest trend (Sharpe, 1968).

, Following the discovery of the Mattagami Lake Mine deposit in

1957, many geologic&l studies have been made in the area (Latulippe,

1959; Jenney, 1961; Sharpe, 1968), but the most comprehensive and

up-to-date one is by MacGeehan (1979) on the geochemistry and petrology

of the vo1canic rocks and massive sulphides on the northern limb of the

anticline to the east of the Bell River (Fig. 1.1). The lucid ~

description of the geochemistry of the 1east altered and altered

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Fig. 1. 1 Regional geology after Sharpe (1968) and locatIOn of Matagaml . in Quebec (inset maps) .

Local geology after MacGeehan (1979): NR (Norita rhyolite);

BCR (Bell Channel rhyolite; BI, B2~ B3, B4, B6 and B7 (basalts); FP (andeslte).

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volcanic rocks and the proposed geothermal model for the genesis of

massive sulphide GMacGeehan, 1978) has made a great contribution to 'the ~) understanding of the area and much of his work has been taken as· the

base of the present study.

A total of twelve Zu-Cu massive sulphide deposits, ranging in

size fram 100,000 tons (Bell Channel No. 1) to 25 million tons O1attag~

Lake), have been discovered in volcanic rocks on either side of the

anticline. AlI the deposits are broadly faund along rhyolite-basaIt

contacts. The "Key Tuffi te", a cherty tuffaceous layer, is the marker

bed in which aIl the massive sulphide deposits on the southern limb

occur (Sharpe, 1968). The "Key Tuffite" has not been recognized in the

northern limb and, with the exception of the Garon Lake deposits which

lie stratigraphically higher in the sequence, aIl the other deposits are

associated with a continuous rhyolitic horizon at the base of the exposed

volcanic succession QMacGeehan, 1979). Considering the volcanic nature

of the host-rocks, the clustering distribution of the Zn-Cu massive

su1phide deposits, conformability, internaI metal zoning and associated

wall-rock alteration, a volcanogenic exhalative origin has been proposed

(Roberts, 1975; MacLean and MacGeehan, 1976; MacGeehan, 1978)'.

1.2 Mining Activity at Radiore 2

The history of the mine began with the discovery of massive

sulphides on the property in 1961 following a ground E.M. survey.

Exploration drilling outlined a small orebody of approximately

150,000 tons grading around 3.0% of combined copper and zinc .. The

massive sulphide lens is stratiform and lenticular in shape, laying in

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a subvertical position approximately 15 meters below glacial depasits

~ps 1,2 and 3). However, the upper portion of the lens was eroded

before deposition of the tills, suggesting that probably only half the

original orebody was left in situ.

Mine development work started in 1975 by driving a decline ramp

CMap 4a) to provide access ta the orebody. Because of a fall in copper

priee, operations were postponed and only resumed in December 1979.

Mining of the deposit was contracted out by Mine Noranda Limitee,

the present owner of Radiore 2, ta Mining Corporation of Canada, which .

completed the ramp to the bottorn lense and developed two mining levels

~p 4c and 4d) with the object of dividing the ore into two zones.

Due ta the shallow depth of the ore the till was removed. Long-hale

drilling for blasting purposes was expedited frorn surface and from level

No. 1. The ore was then blasted in large slabs towards a generally

vertical face of the stope QMap 4b). The broken ore was recovered

through draw points and trucked ta the Orchan miIl at Mattagami Lake

Mine for further processing.

Ore in the mine was exhausted in August 1980 but the workings

were kept open for further exploration dri11ing.

The total amount of ore treated at the mil1 was 153,862 tons

containing 1.34~ Zn, 1.57% Cu, 0.25 troy oz/ton Ag and 0.009 troy

oz/ ton Au.

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CHAPTER 2

TI-ΠGEOLOGY AT RADIORE 2

2.1 Introduction

Apart from an unpublished report by M. Woakes (1961), resident

geologist of Radiore Uranium Mines Ltd. who first established the

stratigraphy, only Sharpe (1968) and MacGeehan (1979) had previously

studied Radiore 2 Mine.

M. Woakes (1961, was the first to describe the mine geology , <_/

through the logging of core from 38 drill-holes. The hydrothermally

altered volcanic rocks have been meticulously described and his clear

report is the only complete documentation of the original drilling,

since part of the drill-core has been lost.

The first general outline of the geology of Radiore 2 was

reported by Sharpe (1968). He termed this deposit Rpdiore "East" to

distinguish i t frorn Radiore "A", the present Nori ta Mine, and interpreted

the volcanics as being enclosed ~ithin the Bell River complexe At the

base of the succession he recognized a unit consisting of andesitic lava

passing upwards into siliceous breccia, chloritic and biotitic schists,

and laminated and brecciated siliceous rocks. Above, the sequence

continued into another andesitic flow ta terrninate against a gabbro unit

which forrned the north wall of 'the volcanic rocks.

MacGeehan (1979), through detailed surface mapping (Fig. 1.1),

found that the volcanics do not lie as an enclave within the complex but

are continuous throughout the area and are cut by nurnerous sills and

dykes formed as subsidiary intrusions of the Bell River complexe He also

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. -I .. _~-

revised the stratigraphy, ree6gnizing a rhyolitie unit (Norita rhyolite)

at the base of the volcanie succession whieh was overlain by a spilitized

and silicified pillowed basaIt (BI), and above which a massive devitrified.

and chloritized rhyolite (Bell Channel rhyolite) was laid down just before , ~

the emplacement of the Radiore massive sulphide deposit. The Bell Channel

rhyolite was in turn overlain by more altered pillow basaIt, which he

interpreted to be the B3 basaIt, before the volcanic stratigraphy was

truncated against the southern border of a thick quartz-diorite sill.

Given the poor preservation of these rocks it is aImost impossible

to classify them correctly_ This study proposes that three metarhyolites l

CNorita rhyolite, NR; Radiore rhyolite, RR; and Bell Channel rhyolite,

BeR) are intercalated with two mafie flows 2 (Bla, metavoleanic and Blb,

metavolcanic) which forrn the stratigraphie succession at Radiore; later

injeeted si11s and dykes form the. present geologieal setting (Fig. 2.1).

A gealogical map of Radiore 2 OMap 1) and three geological cross­

sections OMap 2 and 3) have been canstTUeted and presented after the

Appendix.

2.2 Eruptive Sequences

On the basis of their stratigraphie position (Fig. 2.2) five

major mappable units were defined. Mïnor units occur but do not seem

ta persist laterally and probab1y represent continuous emplacement of

discrete cooling flows over new1y forrned lava and metasediments.

The base of the vo1canic succession is interpreted by MacGeehan

1 Historical1y reported as rhyo1ftes therefore in this study the usage of previous workers will be followed.

2 The base of Blb metavolcanic is in part metasediments.

\..

~ .. ~', .", ~~ ~': ~;

t -i{ ,

l' "',

t /

{

~

l

\ \ , 1

1

\ 1 \ ,

1) ~ '\ ,

\~.' , j"

- 12 -

Schematlc Correlation of Horlzontally Projected Boreholes

.)

.Jo M.cG •• h.n(1979)

83

BCR

81

NR

Fig. 2.1

UA 12~ .... + .. +

ft- + +

EE18

1. + + .. ... '" .. ... + .... r- + ..

+ .. .. ft- + ..

'" .. + .. +

7

\

Qu.rtJl-Dlo,lt. alll

a.1I Cil.,,,, •• .... ~ollt.

M.t • .".4c.n'c (81b)

R.dl .... Ahrollt.

(at.)

NorlU "hrollt.

./

Proposed stratigraphie succession at,Radiore 2 Mine derived fram diamond drill cores. Position and bearing of drill'>'" holes is reported in Nap 1. To the reft is shown MaeGeehan's interpretation (1979).

'.

, , f ,

.. f

c

-(

l' v - 13 .,

\

UR-12 0 ......

Coal' •• gralnee! Quartz-Diorite 1

J

Fine g,alned Quartz-Diorite J~Dy"

... .................. ......

......... .,...,. ... "",. ~ ......... ... o---"lI'­~o,..~ ............... )

"-----"'-----,.. ....... wtm- .... ...........m Dark ve.leuler Rhyolite D_ ..

"""'- T...m ~':'~. c--=~ 0,'.

Chlorltlzed veslculer Rhyolite 'Blue'quartz-.ya Rhyollt.

Tllff'{l)

Chlorltlzed Matavolelnle

Ma.slve,breeclatad and ehlorltlzed Rhyolite

and

Tuff(1) or Mataaedlment (1) --end

Chlorltlzed Rhyolite Strongly altered QUlrtz-Dlorlte(?)

Chlorltlzed Rhyolite

.............. Hlghly ehlol'ltlzad Ind IlIIelfled

Metavolelnle

0._

Mlel'ogrlnlte'

SUICIfIecl Metavolcanle 9 20 :19

~ ... "" ... ~Dyo .. .

~ .......... ~o, ... ' ~Oy ••

~ ................... ,...,.........1~Oyti.

~ ......... ....... ...,..,... ....... ..., ... ~ ...... ~ ... ""' ...

10 20 pm

Fig. 2. 2 Detailed geological description of UR-I2 drill-hale. eut through the entire stratigraphy at Radiore. "

UR-l!2

f ).'; ~.

l f

l 1

f !

1

\ 1

\

. ' c

(

- 14 -

\ " , "'-1 .. _'

(1979) to be formed by the Norita rhyolite and in this study it was

recognized in one of the older diamond drill-ht.es (EE-3S). It was not

inter~ected in UR-12 (Fig. 2.2), logged as far 632 metres. However, (,

as the UR-12 drill-hale was deepened, a rhyoli e was intersected at

greater depth (A. Bonenfant, personal communication). If our inter-

pretation is correct this latter uni,t should be the Norita rhyolite. L

The Norita rhyolite is overlain~by 30 ta 50 metres of metavolcanic

(Bla). MacGeehan described this unit as a massive pillowed basaIt. The

present interpretation agrees with the massive appearance of these rocks

but no pillows were identified in the unit. The rocks are highly

altered and textureless and exhibit gradational changes into the over-

lying Radiore rhyolite. From the reconstruction of drlil-hole data they

appear ta have been deposited on the eastern flank of a topographie high

(Map 1).

The Radiore rhyolite (RR) was originally interpreted by Mac Gee han

(19v9) to be the equivalent of the Bell Channel rhyolite (BCR) which he -\

first described at the Norita mine. They are indeed very sllni1ar, bath

o~ten amygdaloidall with a massive devitnfied texture, but with the

basic difference that tridymite crysta1s are distinctly displayed in the

Bell Channel rhyolite, a diagnostic characteristic elsewhere for the

BeR, (MacGeehan, ,1979). The Radion' rhyolite is often chloritized and'

transected by microcrystalline quartz veinlets. This rhyolite also

cantains layers with fragmented and perlitic textures intercalated with

tuffS or metasediments .

l The terms vesicular and vesicles are often used in this study because in the origin of the amygdaloids was indeed by the filling of vesicles,

"and in my. opinion this term describes better sorne textures observed.

...-,./ \

1

1 - 15 -

The Radiore rhyolite is overlain by Blb metavolcanic interpreted

by MacGeehan as resembling B3 basaIt and being pillowed. By inspecting

the mine drift fram which the ramp gives access to level No. 1 (Map 4c)

no pillows were recognized. The rocks look similar to Bla. They have

a cleaved appearance ab ove the ore zone suggesting that this part is '

fonned by rnetasediments while the rest rnay have indeed been bas ic fleWs.

The Bell Channel rhyolite displays quartz phenocrysts and also

appears to be the least altered of aIl the extrusive rocks. Much of

this unit is a massive devitrified amygdaloidal rhyolite in excess of

40 metres in thickness and is eut to the north by a large quartz-diorite

sille Ta the south, it grades into metavolcanic tocks. The BCR-Blb

contact is arbitrarily drawn on the basis of colour and texture changes.

A poorly developed lateral unit terrned quartz-eye rhyolite occurs towards

the base of BCR (Fig. 2.2). It proved difficult to relate it as part of

the rhyolite flow or a rhyolitic intrusion.

2.3 Intrusive Rocks

A thick quartz-diorite sill transects the upper stratigraphie \

sequence at a low rg1e (Fig. 2.1). From the core logging, twa distinct

rnappable units, on~ coarse grained and one fine grained, were identified.

<'';' Although chilled rJrginS were not always c1early observed the two rocks

are interpreted ta have forrned as multiple intrusions.

The quartz-diorite sill has in turn been intruded by thin, rnostly

aphanitic, diabase dykes which have been deflected into fractures giving

rise ta an anastomosing pattern observable in the rampe

To the west of the mine an ENE striking pyroxeni te dyke outcrops

.!--~-~ .......... _"-' -~-' '-"_._----......:;:=~-~ . ....;":=:~~~"-'.---',"'-,--'"'----~ !...._. ~ .... - - -

, ,

r

f

. (

(

- 16 -

,

and cuts the Blb metavolcanic. It is ~eted 1

r gabbro dyke intruding the quart·z-diorite rnapped in

MacGeehan (1979, Fig. 4.3).

to be part of the

the Radiore rarnp by

The ex:trusive rocks, the earlier intrusives and the orebody have

been injected by a series of amygdaloIdal dykes, found in places ta bOe

fonned of at least two success~ve intrusions, as the same rock type was 1

observed chilled against an earlier intrusive phase.

2. 4 Structure

The facing of the volcanic rocks is inferred by the position of

the orebody which generally lies above fe1sie vo1eanie rocks 0 At

Radiore this indicates a norther1y direction. Furthermore, underground

mapping of the massive su1phide ore revealed the orebody has an tmdulate

profile, with topographie .1ows and highs at the rhyolite-massIve ore

contact which would indicate this contact was the depositionai surface.

On the contrary, the contact wi th the overlaying roc~s is more linear

and thus moreso interpretable as the top of a fi11ed depression ~ 5).

The same conclusion has been arrived at by observing the mesoscopic

structures within the massive ore in which the convexity of the ore beds

is constant1y facing north.

TJ:le strike and dip 'Of the vo1canic rocks are re~pectively E-W and

subvertical. Variations in the dip range within 15 degrees from vertical,

interpreted ta be due te original irregularities in the rhyolite

palaeosu'f;ce which were further inflated by the emplacement of sills

and dykes and by f01ding.

A fauit is interpreted to have fonned soon after deposition of

._--_ ..... - -- ~. ----.--

il'l1..<.

t " 17 ~

• the ore at the west end of the lens. It cuts across the orebody at a

low angle displacing the upper bl<O~ a short distance to the east (Map 5).

Small subvertical faults and shear zones trending roughly NW-SE

have been mapped throughout the mine ramp by MacGeehan (personal corronun-

ication). An extensionai fauIt with similar trend but cutting the

orebody and subsequently intruded by a gabbroic dyke was mapped in level

No. 1 (Map 1). The magnitude of the strike-slip is in the order of one-

haH metre and can probably be related te the same phase of faul ting

that produced the Radiore fault inferred further east by MacGeehan (1979).

2. 5 Metamarphism

The metarnarphic evolution of the volcanic r6cks can be di vided

into three major stages: seafloor weathering or halmyrolysis (high ta

low temperature alteration), high temperature hydrothermai alteration

and regional metamorphism. No reliable criteria were ~ound ta disting-

, uish the first twa events as they both presumably attained greenschist , '

;' faci,es.> HQwever, it is interpreted that hydrothennal alteration, active

during fluid circulation in the geothermal system, is hy and large

respons.ible' for the mineraI assemblages observed, and further reference - , ' '-~'~-

to altetation is to this type. At Radiore, alteration was -followed by

local contact metamorphism of quartz-dioTlte sill and by regional metamorphism.

In this study a regional metamorphic assemblage was recagnized. It is

related to the oligoclase - actinolite (hornblende) - chiori te zone

CWinkler, 1979)"typical of metabasaltic greenstones and diagnostic of

the lower amphibolite facies.

~, '

..

(

- 18 -

CHAPI'ER 3

PETROGRAPHY, ALTERATION AND ~TAMJRPHISM

3.1 Introduction

AlI the volcanic rocks in the vicinity of the mine have been

severe1y altered and only sorne of the more felsic flows and the intru­

sives have retained the imprint of their igneous fabric. MacGeehan

"

(1979) h~s lllterpreted BI ta be basaIt in orlgln. In thlS study, without .

attemptlng ta decipher the orIginal character of the rocks, remnants of

igneous fabrlc have been observed ln the less-altered Bla, and reliets

of the early 'alteratiort assemblage are found ln samples which have now

different mineraI assemblages. These observatIons support the inter­

,pretatlon that the Ela unit was origlnally an extrusive rock, and sub-

sequent mineraI changes were essential1y related ta f1uid circulation.

The metavo1canics and metasediments above the orebody (BIb) have similar

mineraiogy but they appear to be less altered.

Owing ta the fine-grained nature of the mineraIs and the numerous

reaetion products formed, the c~rrect mineralogical identification for

sorne mineraIs was estabilshed with the aid of an electrOn microprobe.

'" Otherwlse, mineraIs were identified by standard opticai means.

On the basis of th15 petrographIe study the stratlgraphy has been

rearranged as 1S shawn in Fig. 2.1. Data on the thlckness of the valcanic

sequence have been deriyed entire1y from the drillLhole UR-12, the only

hale to completely traverse the section.

The Norita rhyolite is not discussed here; as already reported its

" .' 1 ",

,"

"

r.

\

, ,

(

- 19 -

presence was firmly established at the base of the stratigraphie column

by MacGeehan (1979), and It was encOlmtered in UR-12 at depth.

3.2 Metavolcanic (Bla)

Samples of this unit would nonnally be mapped in the field as

"andesite" or "dacite" and when strongly altered as "chloritized basait"

or "chlori tized andeSIte". Towards the base a quartz-biotite Tlch zone,

rnapped as sllicified rock (Fig. 2.2), interfingers with other chloritized

metavolcanics. The degree of chioritization tends ta decrease upwards,

and rocks there appear to be more acid than at the base of the unit.

In the least altered rocks (RAD 60)~ primary plagioclase laths

showing inciplent saussuritization are discerned (Plate l.l~. Small

quartz grains displaying continuous optical extinction are often

surrounded by radiating spherulitic structures or parallel criss-crossing

arrays of quartz-albIte immersed within a devitrified glass mesostatis

of similar composition. There is no evidence that these quartz' grains

are magmatic in origin, they are instead interpreted as forming by

devitriflcatlon of the glass. ChIorlte grains have a preferred

orientatIon and chlorite wraps around felsic domalns probably fonned by

an earller alteration. Chlorite encloses rellcts of green-brown biotite,

(Plate 1.2). Actinollte-epidote-pyrlte i5 a characterl5tic assemblage

found in veins cross-cutting the above mineralogy suggesting flowage of

later Mg-Fe bearing fluid. Filiform quartz veiniets pre-date the

actinolite veins, but this type of sllicification ln open spaces 1S

probably minor. Eisewhere 5ericite may be part of the main assemblage

and carbonate veiniets have aiso been observed.

1 These reference mnnbers are to rock samples listed in the Appendix.

... t.

(

- 20 -

Toward the base the metavolcanic becomes more amygdaloidal and

chloritized (RAD 76), with large but rare outlines of plagIoclase

phenocrysts (Plate 1.3) pseudomorphed by chlorite, quartz and occasionally

biotite, dolomIte and, rarely, by calcite; they are total1y embedded

in a mesostaslS with a simllar assemblage and resemble the amygdaloidal

fe1dspar phyric Bl basaIt described by MacGeehan (1979).

In sorne samples biotite foI1llS an intricate network separat~ng

small domains in which chlorite-dolomlte-quartz is a st~ble assemblage

(RAD 77). It is interpreted to represent the products of an eariler

alteratlOn subsequently affected by K-metasomat ism (Pla te 2.1).

Other thin sectIons present a more complex history; poikilitic

quartz grains (Plate 1.4) are enc10sed in numerous aggregates of biotite

and chlorite (ch1orite pseudomorphs of biotite) wIth extensive patches

of do1omt,~ suggesting that these alteration mIneraIs fonned during two

s~parate episodes: K-metasomatism followed by chloritlzatlon.

Characterlstic of K-metasomatism are large (2.5 mm in,length) pyrite

crysta1s.

At the very base of the unit the texture appears to have been

totally reconstltuted: ,quartz and plagioclase grains fonn irregularly

shaped lsolated patches or a continuous netwark that is difficul t ta

Interpret. These graIns contain numerous blebs or rod-like microliths,

either as isolated indivIdual crysta11ites or as turbid aggregates of

mineraIs that are almost impossible to Identify.

Highly chloritized rocks (RAD 82) are textureless; chlorite is , ,

the major constItuent; the pseudomorphlsm of chlorite after bIotite 15

J

•

(

- 21 -

almost complete; the carbonate mineraIs have been dissolved l~aving very

Iittle or no trace or earlier alterations.

3.3 Rad10re Rhyolite (RR)

The Bla umt passes gradatlOnally upwards into the Radiore rhyolite

. and because of pers lstent alteration the contact 1S difflcult to de fine .

At its base, the Radiore rhyolite is largely made up of fragmentaI

and tuffaceous material, sorne layers of Wh1Ch may be metasedlIDentar)' Toc.Ks.

Towards the top massive rhyolite predOJru.nate5.

The fragmentaI rhyolite (Plate 2.2) 15 usually composed of micro-

crystalline quartz and irregularly shaped plagIoclase grains surrounded

by chlorite. This texture has been formed by chlorltlc alteratl0n.

The tuffaceous material 1S petrographically simIIar to the frag­

mentaI rhyolite with thé exceptIon that biotite IS the major component.

Plat y mineraIs tend to be aligned along dIstinct foliation planes

(Plate 2.3) which may res~lt from dIffusion creep. It lS not always

clear whether this texture is an onginal charactenstic of the rock, or

is a result of K-metasomatism dUYlng wateT-rock interaction with grain

boundary diffusion and fluid transport changing earlier features and

ultimately mlffiicing sectlffientary textures. Drill-hale data do not

enlighten the problem and the same rock encountered underground (Map 5)

offers littie help in InterpretatIon.

The massive rhyolIte displays a varlet y of textures reflecting

compositional differences. Sorne samples (RAD 26) contain large

glomerocrysts of altered equant sodie feldspar wIth rare relicts of beta-

quartz and clusters of chlorite and sericlte forming the central core of

r

t l ,

- 22 -

larger turbid devi trified glassy "fragments" cemented by an intricate ~,

network of polygonal quartz graIns fesembling perlitic cracks (Plate 3.2).

Cordierite occur as clusters of subhedral crystals, now invariably

altered to pinite, surrounded by very fine-grained devitrified glass /

domainds filled with patches of chlorite. In plane light devitrified c

glass appears fa contain subrounded to rounded globulites (Plate 3.3) \

which are camoïflaged within the matrix ~der crossed nicols, and can

be seen only by theIr indistinct ferruginous rims. They-are probably

microvesicles formed upon extrusIon. Another common texture displays

larger vesicles filled with micropoikil~tlc quartz grains wlth indented

boundaries and a core made up of ei ther opaque mineraIs or the same

material observed in the mesostasis (Plate 3.4). The less massive

rhyolite (RAD 62) shows turbid spherulitic domains (Plate 2.4) and

polygonal quartz grains imnersed in a devitrified glassy matrix and #

separated by thin bands of platy mInerals growing prefèrentially along

microsurfaces. At hlgher magnification, the rnesostasis and to a lesser

extent the spherulitlc domains and polygonal quartz grains contain

numerous rod-like microlites or more carnplex networks of serIcite and

biotIte at graIn boundarles, Biotite and sericIte are preferentially

foliated. The spherulltic domains have a micropoikilitlc texture

displaying dissolved surfaces (Plate 3.1), outslde of which néwly-formed

grains accumulate, suggesting an active role of intergranular fluids.

3.4 Metavolcanic (Blb)

WhIle the basal contact of the Blb metavolcanic with the Radiore

rhyolite lS sharp, the upper part of the flow, which passes into the

, "

if' ~j

~

'c

'" " '. [

t , , . "

(

---,~--

,.... t~

~~r=-=-"'),.oP\ li

- 23 -

Bell Channel rhyolite, is poorly defined. To the west of the mine

workings the Blb unit is a fine-grained chlorit1zed flow with hyaloclas­

tic textures: these provide the only evidence that depos1tion of these

rocks took place ln a subaqueous environment. Above the maSSIve sulphIde o

ore the rocks are instead h1ghly sch1stose and sorne of the better cleaved

samples have no relictjlgneous fabric but petrographically shows texture

of subrounded clastic quartz gra1ns embedded in a fine-grained matrix

and interpretable as being metasediments.

The sample from the western flow (RAD 100) shows evidence of

having ,oeen thermally metamorphosed by displaying a granoblastlc poly­

gonal texture of quartz and plag1oclase, while amphiboles have retained

in part theIr igneous fabr1C (PI?te 4.1). Irregularly oriented fibrous

tremolite-actinolite grains exhibit progressive chloritization.

In other samples the quartz-zoisite-chlorite assemblage is

obs~ed, and occaslOnally the appearance of green hornblende, as a

transformatIon from actinolite and indicative of lower amphiboli~e

met~rphic grade (Winkler, 1979), 1S also an important characteristic

of these rocks. The metasediments are made up of equigranular quartz

commonly embedded in wel1-oriented chloritlC planes of foliation. Most

of the chlonte is c1inochlore, but some lS pennine displaying a~normal

shades of blue, violet and brown Interference colours. In sorne sections

biotite, zoned in a sheaf-llke or s~bparallel fash1on, becomes the

predominant constituent of the rock. Microscopic flakes of mUscovite

also occur in biotite domalns. Mrrnute granules of magnetite and pyrite

characterlze thlS unit and are Interpreted to have been mostly deposited

contemporaneously with the metasediments.

(

,~, 24

<, ,.,.

" t..

1

'(

3.5 Bell Channel Rhyolite (BCR)

The Bell Channel rhyolite lS similar to the Radiore rhyolite but,

as already mentioned, the presence of tridymi~e crystals is distinctive

of this unit (Mac Geehan, 1979).

Texturally this unit shows a predornlnance of ovoid to subrounded

vesicles (Plate 4.2) fliled mostly by quartz (Plate 4.3) and rarely by

carbonate graIns. The vesicles are randOrnly distributed, range in size

from 0.5 mm to 2 mm in diameter (Plate 4.4)~and are rimmed by magnetite

grains (Plate 4.4). Under crossed nicols vesicles display two types of

quartz textures: (1) a medium gralned varlet y with indented or irregular

baundarles and showing undulated extInction, found mostly inside the

vesicles; and (2) a fine gralned varlet y, predorninantly at the rims of

the vesicles or otherwise dispersep in the mesostasis. Bath are believed

to farm ln the same way: by migration of silica. The dlfference in grain

size can be explarned by the different rates of nucleation of quartz

within silica-rich fluids which are strongly oversaturated outSlde the

vesicles but are only saturated as they migrate into the vesicle.

Spherulitic texture has also been observed. The morphology of

the spherulites shows a continuaus spectrum of radiating sheaves influenced

by a common control on crystallographic orientation and extinctIon in

slightly different posItions (Plate 5.1). The sheaves are irregular

intergrowths of quartz and albi~e which are arrested by impingement of

neighbauring sheaves or phenocrysts creating a mos~ic resembling

syrnplectlc textures.

,". '.

e

,.

(

- 2S -

Quartz phenocrysts, alpha-quartz paramorphs after beta-quartz,

,are rarely euhedral (Plate 5.4) and often embayed (Plate 5.3). Sorne

show incipient recrystallization with fine microcrystalline products

similar to those observed around the vesicles. Sorne equant grains have

optleally continuous reticulated borders with frequently elongated

crystals of tridymite (Plate 5.2). Large sodie feldspàr phenocrysts,

invariably turbid with blurred crystal boundaries, and occasionally

cordierite grains are also found. Brown to green biotite flakes are

present but they are mostly altered to chlorite.

Cross-cutting chlorite and quartz veinlets indicate that the rock

has locally been affected by later chlorltization and silicification.

3.6 Gabbro Dyke, Quartz Diorite Sill and Diabase Dyke

The gabbro intrusion (RAD 101) was sampled on a small outcrop to

1 the west of the mine where it is in contact with Blb (Ma.p 1). This

sample is composed mainly of hornblende crystals and has been interpreted

to represent the basal zone of a much thicker gabbroic unit encountere~

by drilling to the west of the property, and correlable to the ENE

striking gabbro dyke mapped by MacGeehan (1979) in the upper part of the

ramp at Radiore 2.

Apart from a srnall intrusion below the orebody (Fig. 2.2), quartz­

diorite forrns a large sill that intrudes t4e volcanic pile at a low angle

above the qre. In spite of the uniform mineralogy, it was possible to

dist~guish a coarse and a fine grained type, and at their contact a

chilled margin allowed the sill to be interpreted as a composite body

formed by two different intrusive phases. Plagioclase occurs as euhedral

<-

- 26 -)

to subhedral grains wi th embayed and serici tized borders. Where al teration

is more intense feldspars become pale brmm, displaying a turbid kaolinized

appearance. Micrographie quartz intergrowt~s are present but rarely

regular; they may have been modified by albitization. Hornblende forms

individual and irregularly-shaped pseudo-pokilitic prisms with large areas

altered to chlorite. Sphene, magnetite and ilmenite are COlTD11on.

Diabase dykes have been clearly recognized only when intruded into

the quartz-diorite sill, but in the metavolcanic the distinction is not

obvious.

3.7 Gabbro-diori te Dyke

The gabbro-diorite dyke, originally tenned by Woakes (1961)

"greenstone", has never 'been recognized outside this ar~a (MacGeehan,

personal communication). Intruded mostly along fractures, it was

encountered in several drill-holes as small intrusions ranging in thick-

ness fram a few centimeters to larger bodies of a maximum 01; 10 metres

(fig. 2.2). From drill-hole correlation they appear to have a pinch and 1

swell shape and to have developed along an early fonned fracture system.

From cross-cutting relationships the emplacement of ~hese dykes post­

dates the quartz-diorite. Their relationship with the diabase is not

known, but they probably represent later intrusions.

Chilled margins within Iarger bodIes of gabbro-diorite indicate

they do not represent a single event but fonned as multiple intrusive

phases from the same parental magma.

AlI the samples show a s:i.milar mineralogy with elongated and

disoriented laths of amphibole altered to chlori te and of feldspar almost

., " -~ ~ t .... v - f

·l

f r

(

- 27 -

canpletely saussuntized. The most distinct feature is the presence of

randomly distributed amygdales mostly composed of chlorite and calcite,

which give a spotty texture to the rock in hand specimen. Muscovite,

zircon, sphene and opaques (mainly magnetite) are accessory mineraIs.

Cross-cutting chlori te and s ilica veinlets are found in sorne samples, •

indicating that fluid circulation persisted long after the fonnation of

the vo1canic pile. 1

3.8 Rock Alteration ~

Massive su1phide deposits are invariably described in the fi

literature as being associated with rock alteration, and this alteration ,. has generally been found ta be restricted ta rocks beneath the massive

suiphides.

In the Noranda district a typical hydrothennal alteration

assemblage is ccmposed of chlorite, sericite and silica, with chlorite

closely associated with ore (Kelly, 1975). At Matagami, Roberts and

Reardon (1978), who have studied the Mattagami Lake -mine, interpreted

-that talc, chiorite and ta sorne degree seri cite represent mineraIs

developed by alteration procésses while actinolite, biotite and

stilpnomelane are thought to be metamorphic products. Also at Matagami,

MacGeehan et al., (19.81) have reported that hydrotherma1 alteration at

Norita mine has produced variable but intense chloritization in the

rhyoli tes. Furthennore, MacGeehan and MacLe an (l980a) have proposed

tha~ convectIve circulation of fluids below the Garon Lake rhyolite

produced an intense spili tization and mineraI assemblages in the

greenschist facies. At Radiore similar mineraI assemblages occur in the

\

.~

.J " )

, ,

-/

1 i

~I

1 , 1

(

- 28 -

metavolcanics and support the interpretation that the rocks have been

hydrothennally al tered before being affected by reg~onal metamorphism. . '

To coherently .develop the discussion, it is COJ~venient ta consider

first the alteration and afterwards the implication of reglonal

metamorphism. However, i t is important to remember that since regional

metamorphism was superimposed onto the hydrothermal alteration, the V'

alteration mineraI assemblages have been subjected ta a different P-T,

and may have re-equilibrated. Therefore, mineraIs observed today have

not necessarily been formed under hydrothermal conditiuns.

Assuming that the c~emical character of the original rocks

"discussed earlier in this chapter is not disputed, the presence of

different mineraI assemblages implies that these changes resulted from

modified fluid circulation.

On the basis of the colour and textures associated with specific

" mineraI assemblages, it is possible to distinguish the aIteratio~ effects

and group those of:

1) spilitization

2) potassium metasomatism

3) chloritizat~on 1

1) The spilitized rocks, are usually light in colour ranging from 1

• grey-green to light-green ethey would be corrnnonly tenned "andesite" or

"dacite" in the field). Two equilibritun assemblages are petrOgraPhiCa~lY observed: 1

a)

b)

, ,

" 1 tremol i te-actinoli te-plagioclase-chlori te-quartz-serici te 1

actinol i te (hornblende) -plagioclase-quartz-epidote-chlori te-bioti te ! 1

1 1

1. 1

..

• . " '",f

~ ,-.~ ),

j l ~ Iii

./ l.

!

1 1

)

- 29 -

"

The plagioclase generally varies fram oligoc1ase to andesine and

occas ionally primary phenocrysts and renmants of th~ igneous fabric are

observed (Plates 1.1 and 1.3). Samples often show cross-cutting veinlets

of quartz, chlorite, or actinolite-epidote-pyrite, obviously related to·

later phases of fluid circulation.

The spilitization assemblage has minor biotite which occasionally

shows incipient ch1oritization (psuedomorphism, Plate 1.2). It is .. suggested that this biotite (OT similar precursor) fotme~ during K-

I,

metasomatism. The reasoning ta equate such a relationship with a sub-

s~quent fluid phase lies on the petrographie evidence that K-metasomatiz~~

rocks display a similar biotlte-chlorite transformation.

2) The potassium metasomatized metavolcanics are light in co1our

and have been mapped as silicified rocks. Petrographjcally they have a

recrysta11ized texture (Platè' 2.1) and are defined by the assemblage

biotite-plagioclase (albite/oligoclase)-dolomite-ch1orite -quartz-pyrite.

This a1teration was intefsected towards the base of Bla metavo1canic by

drill-hole UR-12 and sorne samples show relict domains of ch1orite-

dolomite-quartz.

The metasediments or tuffs are much darker in colour and exhibit

a variable mineralogy. The observed biotite-rich assemblage (Plate 2.3)

is unlikely to have been derived fram law-potassium tholeiites,

MacGeehan (1979), but is probably related to the potassic alteration.

3) The chloritized rocks are dark green and cDuld be easily mistaken

~.,.. '---for altered "basaIt" or "andesite". Chloritization is found as a

pervasive alteration main1y below the orebody but it is not petrographically

( possible to make a distinction between chlorite for.med during spilitization

~-,,~_ ... ----- --- ---

t

(

..

- 30 -

and chlorite forroed during this later process. Qualitatively the sharp

increase of chlori te is observed in hand spec imen and thin-section, and

cannot be accounted for by the breakdown of the ferromagnesian mineraIs. 0'

It can instead be explained by an addition of magnes,iwn to the rock

(in this respect the chemistry ts indic~tive: samples show values weIl 7

r

The existence of different mineraI assemblages points to a

paragenetic arder of alteration 50 that the temporal and spatial

relationships between the various phases can be evaluated.

Relict phenocrysts, occasionally and only observed in the

spilitized rocks, indicate that this alteration is associated with the

least altered rocks. The widespread occurrance of the spilitized ;'

assemblage implies that it represents the major alteration event in the

area. The clear petrographic evidence of spilitized relict domains in

K-metasamatized and chloritized rocks supports the interpretation of !wo

separate al'teration events. In addition, the consistent texturaI

evidence that chlorite pseudamorphs biotite allows the,intetpretation \ l ,~

that progressive chemical changes in the circulating fluids occurred.

The restricted areas in which intense K-metasomatism and chloritization

are observed suggest that fluids were moving preferentially along

channelways with a small part of the fluids penetrating microfractures

in the metavolcahics and the highly porous metasediments or tuffs, hence

the presence of biotite and chloritized biotite.

It seems therefore possible that two events have produced first

a greenschist facies assemblage (spilitization) followed by a prograded 03

1 Spilitized rocks have much lower MgO and even the least altered basaIt, interpreted to be fractinated, rarely exceed st MgO (MacGeehan, 1979) •

(

1 1

1 f 1

(

"

- 31 -

alteration from K-metasamatism ta chloritization. , 1 Any attempt to speculate further on "the types of alteration is

unwarranted. However, field relationships, mineraI assemblages and

'texturaI evidence allows for a generalized sequence of alteration events.

These are summarized in Table 3.1. l'

Contact metamorohism associated with the intrusion of the quartz-

diorite sills has produced hornfelsic assemblages with grains of pinitized

cordierite mainly in rocks below the massive sulphide ore and close ta the

intrusion.

3~9 Relationships Between Alteration and Metamorphism

From the mineraI assemblages of the altered basic rocks at Radiore

it is interpreted that the hydrothermal alteration was followed by a 1

\ regional metamorphism of the lower amphibolite facies which developed an

assemblage equivalent to the oligoclase-actinalite(hornblende)-chlorite

zone typical of metabasalt (Wink1er, 1979). From the spilitized

assemblage of the metavolcanic a calourless ta pale-green actino1ite is

found to change into a deeper-green hornblende and according to Winkler

(1979) this reaction takes place at about 5000C, rising only slightIy

with increasing pressure. One sample (RAD 78) has no chlorite but

according to Winkler (1979) there are low-grade oligoclase-amphibolites

without chlorite.

At the Garon Lake mine, two ~ north of Radiore 2, Aftabi (1980)

estimated on the basis of [ALJ6\ers~s [AlJ4+~n hornblende in the w;;Ill­

rock that P-T conditions during regional metamorphism (middle amphib'olite

facies) ranged between 4500 - 6000 at a pressure of less than 5 kb. At

,-.. \ ,. ~.

...

'"

- Table: 3.1

Sequence of Alteration Events

,

~

ALTERATIOO FIELD RELATIONSHIPS MINERAL ASSEMBLAGES HYDRarnERMAL TExn1RE 1 (in the metavolca~cs) EVENfS . 1

! 1

1

Tr-Chl-Plag-Q-Ser " tIYdrolitic Rerrmants of· 1

,àtteration • ! 19neous -. o'f fabric. --SPILITIZATIOO Widespread ActQHb)-Plag-Q-Ep-Ser-Chl-Bi mafic mineraIs Silica vein-and lets or'dis-

1 - calcic plagioclase solution and 1

1 plus replacement ~ . silicification by quartz.

j

-- --

Localized at the 1

base of Bla or in ~ K - METASO\fATI SM rnetasediments and Bi-Q-Chl-Dol + K and COZ relicts of

tuffs (Radiore spilitizaticn . rhyolite.or slightly above)

AND . . Mainly below Bla; relicts of Very intense at base, ChI-Dol-Q

Mg 2+ spilitization ŒILORITIZATION otherwise more and

restricted or in ,

Act-Ep chlorite veins in spilitized pseudomorphs rocks. biotite.

-----~

Tr = tremolite ChI = chlorite Plag = plagioélase Q = quartz SeT ::: serici te Act = actinolite

Hb :::'hornblende Ep = epidote Bi ::: biotite Dol ::: dolàmite '.

1 J.

;

----:-> ... ~ _~~:'_-<; l'i;i\"~~~

(

~, \

, (

.... --, .... -.

- 33 -

Radiore total ?~essure is expected to have reached similar condition.

To verify the validity of Winkler's statement that actinolite

changes to hornblende at SOOOC suggesting that this temperature is the

regiona1 metamorphic temperature attained in the area, a different

approach wa~ derived.

Phase relations in the system KZO-CaO-MgO-A1203-Si02-HZO-C02 have

been recently studied by Hoschek (1980), and in thjs study, on the basis

of the petrographic identification of the stable minera! phases, the

metamorphie temperature was estimated using a T-XC02 diagram in an

isobarie system at 5 kb (Fig. 3.1).

In the above system aIl phases are restricted to Fe-free non-

opaque mineraIs and Na-free silicates. Fe is a major camponent in the f

1

rocks at Radiore and is expeeted to be present in sevèral silicates. 1

However, recent studies of Williams-Jones (in press) ;on similar phase 1

assemblages in rocks at lower P-T indicate that the displacement of the

equilibrium with the addition of Fe does not have a significant influence

on the system. Since plagioclase is the only sadie minera! present,

the corrections for reduced anorthite activity aré quite significaht.

At AnSO' except for reaction 2, the equllibrium boundaries would be

lowered by approximately 30°C (A.E. Williams-Jones personal communication).

Qualitative microprobe and X-ray diffraction1 analysis of selected

samples show that the plagioclase composltion varies from albite to AnSS1.

It is apparent that the discrepancy in the An content lies in the mobility

of the albite and anorthite components of the plagioclase in interacting

fluids during alteration. AnSS' probably represents a relict

/ ~

1 Courtesy of Dr. Robert Martin

,

composiïon

,/

1

(

- 34

Fig. 3.1 T-XCOZ diagram at 5 kb showing phase relations in the system KZO-CaO-MgO-Alz03-SiOZ-H20-C02' after Hoschek (1980).

Both sides of reaction 1 are observed in separate spilitized specimens; reactions 2 and 3 in veins; reaction 3 as relicts in further metasomatized rocks; reaction 4 in rock affected by K-metasomatism.

f

, ,

:'

(

- 35 -

of original plagioclase. It is evident, ~owever, that plagioclase grains of

variable composition coexist (but not in equilibrium), because specific

assemblages are not observed associated with plagioclase of different

An-content. Systematic quantitative rnicroprobe analyses of the plagioclase

are required ta substantiate this hypathesis.

_Th~mineral assemblages observed in the rocks are those which

have equi1ibrated during regional metamorphisrn, and relict assemblages.

The rnetamorphic ones are related to idea1ized reactians which may or may

not have occurred at Iawer metamorphic grade.

In the fallowing reactions, those under1ined are deduced frarn the

study of thin sections in which aIl the mineraIs occur in contact with

one another and a~,considered ta represent equilibrium assemblages.

Table 3.Z lists the mineraI assemblage in which these reactions are

observed in thin section.

1) '1 ChI +6 Z+ 7 Q ~ I Tr+ 10 Ant6 H;t

2) 9 An+50 Dol+143 Q ~19 Trt6 2+14 HZOtl00 COZ

3) l Chl+S Dol+lS Q":::- 2 Tr+1 An+2 HzDtlO COZ

4) 3 Ms+8 Tr+4 Hp+32 COZ-==- 3 Bi+3 Chl+16 Dol+SS Q

~I

:1

~ -1 .. 1 ..

~ . ' - ,

r '

,

..

, "":t"f'''~I~~-''''~~''''''fI'I' (...,.."-

- 36 -

Table: 3.2

Selected Mïneral Assemblages Found in the Altered Metavolcanics

RAD 60: Q-Plag(An SSl)-Chl-Bi-Ser-Z-Sph and in cross-cutting

vein: Act-Z-Dol-Py

RAD S9: Q-Chl-Bi-Z-Plag(oligoclase)-ActQHb)-Mt

RAD 100: Ch1-Tr(Act)-Plag(oligoclase)-Q-Ser

RAD 77: Q-Bi-Plag(albite-oligoclase)-Chl-Dol-Py and in relict­

domains: Chl-Dol-Q-Act(Hb)

RAD 79: Chl-Q-Plag(aibite)-Dol-Py and in cross-cuttin~ vein:

Bi = biotite Q ,= quartz Plag = plagioclase ChI = chlorite Z • zoisite Ser = sericite Hb = hornblende Sph = sphene Act = actinolite Dol = dolomite Tr • tremolite Py = pyrite Mt = magnetite

ChI-Dol-Q

1 , Courtesy of Dr. R. Martin: XRD analysis, otherwise the plagioclase composition is estimated fram qualitative microprobe analysis.

r

~ " )

(

f ( , i

37 ,-, .

From the phase relations in Fig. 3.1 the followin~ conclusions

can be drawn. keepin~ in mind that the influences of other elements, Fe

and Na principally, are not taken in ta account.

1) The first appearance of plagioclase sets a minllmum temoerature

of 490oC.

Z) Oualitatively rocks affected by subsequent alteration (reactions '-

3,4) show assemblages stable at greater COZ contents of the fluid; the

opposite is noted for the spilitized counterparts (reactions 1,Z). In

fact, the first appearance of zoisite, which is not observed in any of

the more altered assemblages gives a clear separation of the two

assemblages.

3) The presence of both sides of reaction 1 (observed in separate

samples) tells us that physical and chemical conditions'were set along

this univariant line.

4) This univariant assemblage constrains the field of mineraI

stability to be10w approximately SISoC, and the absence of zoisite in

the more altered assemblage to above 505°C. Further, reaction 3 is

found in the more a1tered assemblages as relicts of spilitization, but

as for reaction 1, petrographic evidences point towards an assemblage

stable a10ng the univariant 1ine.

5) This interpretation is consistent with mineraI assemblages found

in veins which cross-eut the earlier altered rocks. Reaction 3 is

observed in veins associated"with ch10ritized and K-metasomatized rocks 1 1

deeper in the volcanid pile. As fluids move up a decarbonatization 1 1

reaction takes place ~d reaction 2 is the stable phase. The evolution

of the fluids in suggest a consanguinity of the fluids

(

1 ~ , J

l ('\ \

l '

..

- 38 -

active after spilitization.

6) Since the composition of the plagioclase is more sodic than shawn

in the diagram, the net result is a depressed topology at a temperature

estimated between 30 and 500e lower than proposed.

In S1.lIlD1lary, the metamorphic tempe rature between 460 and 4800e is,

in good agreement with the observation that actino1ite changes into

hornblende at about 5000e (Winkler, 1980) and since phase relationships r

agree with the petrographic observations, a pressure of 5 kb is also a

good estimate.

l ,

"

1

. " .. !. ~.:" : "'.' <. ~ .... . - ~ ......' ' ~ .... \." ..

'. _ .• l.· ",.. ., .~ . \" . , ......... ..'

.! ,/\ ~ - II·~·~ $ .l',':' ;'."ri' . ..' ." .... . ' .' .'~' / .. ~. .'. . • . . • ....... . ., " ,,' 1\ , . ,t ~ . ; L' • • l'

'.' "t'- è-tt . , -if:: , ... '-

'v''': ~

1

PLATE 1

111 WeIl '~reserved sodic PlagiOC1aS~'l '1 • irnrnersed in a quartz-albite r:ich me~o~tagis surrounded bv an intrlcate

Inptwork of chlorite. Pldgiocl.lsl' c;how ... incipient saussuritization.

Sdmple RAD 60, Bla 'lt'ldvnl,.lTllc

Cross-nichaIs. View i5 0.9 mm across.

1 2 Green-brown biotite grain • showing a rcaction rim altering

tù chlûrltL'.

Sample RAD 60, Bla '1etavolcanic

Cross-nicols. View i5 0.2 mm across . . "- ._---

1 ~ Large outline of primary sodic • feldspar replaced by chlorite

(chI). quartz (qz) and small grains of biotite (bt). The groundmass is mainlv biotite and chiorite.

Sample RAD 76, Bla '1etavolcanic

Plane Iight. View is 2.6 mm across.

1 ~ Patch of poikilitic quartz • wi th irregular crowded

inclusions uf biotite dnd, rarely, by chIorlte, immt'r'led ln a hiotite and chlorlte rich meqo~ta~is.

Sample RAD 76, Bla Mptavolc,lnlC

Plane light. View i5 0.9 mm across.

PLATE 2

12 1- 1 rre~~~dr to dibc-sh..- ped -----l • pOlkllitie quartz gralnb !

'contdinlng rl'lietS of qll,lrt7-,'hlorltP­Id,,]lmll tl' ,1'-,'-,l'mb1.lg.' "l't ln .! billt 1 tl'-

ri ( Il rlt'S(1c,Ll"I".

Sample RAD 77, Bla ~'Pt.1VO ll-,ln il

Plane l1ght. Vlew i5 0.9 mm across.

2 2 Photograph of a tvpieRI frag­• mertal rhyolite.

Sample from drill-hole EE-35 ~

m 10'3.93 (341 ')

12 3 Outlin, ~;·~~;tly dis801 .. d {,'d-• spar grain embedded in weIl

oriented plat y mineraIs (mainly

biotite) .

1 -

1 Sampie RAD 16, Radiore rhyolite 1 (metaSediments). 1 t ~(l,,~d __ n~cob. View 2.6 mm aeross .

..,/

Isolated spherules showing original radiating structures

" preserved by a series of optically 1 eontinuous sectors of inclusions of 'llLlrt7-albitc> and prob.lbly serieite.

Sample RAD 62, Radiore rhyolite.

Cr05sed nicols. View 2.6 mm across.

..

\

1

PLATE 3

1-3-1- PartI", dissolved spherulitic

[' • M.dn ;,howing n~\..rly formed minerdl~ on the margin of the grain

l, togl'ther 1011 t h growth of pressure "hadow minera1b.

1

1 S.lmple RAD 62, Radiore rhvol ite.

lcrossed nicols. View 0.9 mm across.

13 2 ~~ack~-Corming ~~all--sp~:~~iqal • parting due tQ contraction

during cooling: perlitic texture .

. ',--

Sample RAD ~6, Radiore rhyoIite.

Plane light, View 2.6 mm across. "'-_-.

"

3 3 Globulites within devitrified • glass interpreted to be micro­

Vl'siclp"l formpd aft('r pxtrusion

Sample RAD 26, Radiore rhyolite.

Plane llght. V~ew 2.6 mm across.

3 ~ Amygdaloidal rhyolite showlng • outline of'original vesicles

filled by microcrystalline quartz mantling a core made mostly of chlorite and biotite.

Sample RAD 4, Radiore rhyolite.

Plane 11ght. View 0.9 mm across.

l "

f

1

14.1

PLATE 4

Varldolv orlvnted dmph~boleq (actinolite) pbt'udomorph of

Irvru~vne set in a devitrifivd gld~~v me~oqtasis pdrtlv chloritizeJ.

'4 2--Ov~id t0 ~\Ihr"lInd. d vesicles • -,

1 • texture. The circle shows the 'position of the next plates ~.1 & 4.4.

1 , }

Sample 71, Bell Channel rhyolite.

Plane light. View]5 mm across,

~ 3 Vesic1e filled by quart z 'lhow~ngl

• serrated boundaries and sligh~ , \Indulated extinction.

1

'" Sample 71, 'Bell Channel rhyolite.

Crossed nicols. Viel.' 2.4 mm across

, 1

4 4 The same microphotograph but • sholo/ing magnetite grains rimmling

the edge of the vesic1e and set Jn )il

devitrified glassy groundmass part~y chloritized.

Sample 71, Bell Channel rhyolite.

Plane ligh t. Viel.' 2.4 mm across ~ \

l'LAfI "

51 1{,ldidting 'lpla·rull'-' prl' .... l'rvl'dl • l>v rud-likt., inclu-.i"l1'" pf CjU,lIt/-j

1

,lIhl!" .... et ln [1 ml'f,o<;ta-.I., of dl'vltrl- ; fi"d gIJf,., r!ch in magnetill' gr:lI1\11l' ....

~dmpll' RAD 67, Hell Chann('l rhyulit!'.

Cnl'{'>l'd nicoly. View .'.8 mm acru.,.,.

5 2 ~I;I~a-qUa~~;~p-:-ramorrh of h .. I,}- l • quartz flanked bv a dcn-.t> 'lu"l"rl

of quart7 mIcro!ite<;. Flon!>(ate "pl j- ~

colly continuou<; crystals are Intl'r­preted as beta-quartz paramorphed df[er tridvmite.

Samplt· RAD 67, Bell Channel rhvol!t".

l'Inne 1 ight. View 2.6 mm acros.,.

-~.

5 3 Lmb,lved fl·I iL 01 .Ill'hol-quartz • paramorphed of beta-quartz

flanked by a sodie feldspnr miero­phenocrvst. Embayements are Inter­preted as rebsorbed feature during qUl·neh1ng.

Sample RAD 67, Bell Channel rhyolite.

Plane 11ght. View 2.6 mm across.

" (

5.4 Beta-quartz phenocryst<; bordcred by spherulitic quartz-albite and

showing pressure shadows as a product of integranular fluids. The ground­mass ls made of reerystaillzed gla,., and magnetite granules.

Sample RAD 71\ Bell Channel rhyolite. \

Plane light. View 2.8 mm across.

l, .~

) - 44 -

)

ŒlAPTER 4

WALL-ROCK GEOCHEMISfRY

4.1 Introduction

MacGeehan and MacLean (1980a) have first proposed a tholeiitic

affinity for the volcanic rocks on the narthern side of the Matagami

district and interpreted the calc-alkaline trend of the "intermediate" 1

iflcanic rocks originally put fonvard by Descarreaux (1973) as being

the result of widespread hydrothennal seawater circulatIon through an

origInal basaIt-rhyolite bimodal suite. This interpretation was based

on the geochemistry of the least altered volcanic rocks extruded ab ove

the Bell Channel rhyolite, the B2 ta B7 basalts and the Garon Lake

,. rhyolite. It is lUlfortlUlate that due to the extensive glacial cover the

\

(

-.... _-- -... ,... t 1 ... -... -y,,,~ J'~'!-_'~,,",:,'.'~ ~, N

BI basaIt has only been sampled tram drill-holes adj acent to mineralization

where i t is invariably altered, and consequently the basaltic nature was

primarily inferred by analpgy with the adjacent basic flows.

The present study deals wi th samples which have also been exten-

sively altered, hence no new data is provided on the original nature of

the rocks; therefore the above interpretation is accepted.

One of the major problems encoUfitered in the study was the dis-

tinctian between rhyolite and basic flows which have been heavily

silicified. As already mentioned, the contacts between these units in

the Radiore stratigraphy have always been ambiguous. Petrographically,

the definition given by Bates and Jackson (1980) that rhyolite'is typically

porphyritic, with phenocrysts of quartz and alkali feldspar in a glassy ;

ta cryptocrystalline grounchnass and aften exhibits a flow texture, is

J

(

- 45 -

not a1ways applicable ta a1terea rocks. The a1tered rhyolites at

Radiore are fonned predblllinantly of rnas~ive devitrified glass with

zones of intense ch1oritization. Hence, the difficu1ty in distin-

guishing t;hem f;rom basic but highly silicified rocks is apparent.

Because of these difficu1ties, an attempt is made to separate them

by chemica1 means.

With the exception of the gabbro-diorite dykes which had not

been described before, intrus ive rocks have not been extensively

sampled. Chemical analyses of the intrus ive and extrusive rocks ate

listed in Appendix III-a-b. In this chapter only the gabbro-diorite

dyke of the intrus ive rocks is discussed.

In arder ta estimate sorne of the major geachemical changes in

the absence of relatively fresh rocks, the major and trace element ,

data from fresh volcanic rocks of tho1eii tic a:tfini ty are reported

(Appendix III-c).

4.2 Geochemistry of the Extrusive Rocks

In spite of the alteration it was possible using appropriate

immobile geochemical discriminants to substantiate the tholeiitic

nature of the volcanic rocks. The Ti02-Y/Nb diagram (Fig. 4.1)

clear1y indicates that aIl the rocks are tho1eiitic and not a1ka11ne

(diagram after Pearce and Cann, 1973, Winchester and Floyd, 1976).

j I~

(

(

\ \

- 46 -

Alkalln. Rocks Thol.,Ule Racks

, 1 • 1 1 s 1 1

s

i..c.~. br f\ ,,-)~ , ~ ,

1 il 1

'\,. r--... ....... Y- Ir-: •

, 1 1; C .. It s

o c Il s

0 1 J'J

Y/Nb

\

Fig. 4.1 Wt% TiOZ vs Y/Nb plot of metavo1canics. The alkaline-tholeiitic dividing line is afte.r Pearce and Cann (1973) and the plot a~ Winchester and Floyd (1976)." .

.

CTB = continental tholeiitic basaIt, OIT • ocean island tholeiite, OTB = ocean tholeiltic basaIt, CAB = continental alkali basaIt, OAB = oceanic alkali basaIt. The symbols: basic volcanics (Bla =.; Blb =+); rhyoli,tes (RR =0; BCR =0)

The camparison of Al Z03 with normative plagioclase composition (Irvine

and Baragar, 1971) (Fig. 4.Z) and the MgO-AIZ03-(FeO-FeZ03-TiOZ) cation

plot (Jensen, 1976) (Fig. 4.3), indicates that theyare tholeiites.

Fig. 4.Z Jensen cation plot. It discruninates between calc-alkalic and tholeiitic rocks after Jensen (1976). The symbols: basic volcanics (Bla =.; Blb "..); rhyolites (RR =0; BeR =0)

, :

)

(,

(

r 1

Abo,

10

Fig. 4.3

- 47 -

Calc-Alkallc

.. • Thol.litic

•

o

10 .0 20

Normative Plagioclase

WU Al 0 vs An normative composition plot. Ca1c-a1kalic and tholeittic dividing line after Irvine and Baragar (1971). The symbols: bas ic volcanics (Bla ::.; Blb =.);

rhyolites CRR =0; BΠ=0)

However, because they are sensitive to magnesitnn variation on the fonner

diagram, the most chlorite-rich samples plot inside the Mg-rich basaltic

and kamatiitic basaltic fields. The pervasively chloritized rhyolites

ar: shifted ta the r3ght instead of plotting along the AI Z03-CFeO-Fe203

-TiOZ) bmmdary. In spite of this it i5 sufficiently proven that the

tholeiitic nature of these rocks should not be disputed.

The geochemistry of the hydrothermally altered rocks on a

normative colour index versus normative plagioclase composition diagram

(Fig. 4.4) used to classify volcanic rock types does not distinguish

between rhyolite and basic rocks.

1

,

~

,~

~ ,~

j

'J ,1

[

(

- 48 -

fIf e"

.-ir ~ •

CI if.- • ~

Normative Plagiocla ..

Fig. 4.4 Normative colour index (CI) vs normative plagioclase composition. The diagram is after Irvine and Baragar (1971). The symbols: basic volcanics (spilitized Bla =. ; K-metasomatized Bla = • ; chloritized Bla =.; spilitized Blb =. ; chloritized Blb =+; metasediments Blb = ~; Rhyoli tes: RR = 0 ; BCR = 0; Number refer to sarnp1es listed in Appendix V.

The plot of Ti02 vs MgO gives a gO~d separation of basic volcanic

and rhyolite with the effect that basic r~ckS enriched in Si9z are

sufficiently discriminated from the least altered or the more chloritized

rhyolites (Fig. 4.5).

-..

, , .

\

':-p'"

- 40 -

z.

~ n02 1.5 ~

~ ,-i~ ~

1 1.

!ti '1+-.P Da

:cJ cf

20

MgO , '

Fig. 4. 5 Wt~ TiO?. vs WH MgO. This diagram shows good separation between-basic volcanics and rhyolites. The symbols: basic volcanics (spilitized Bla =. ; K-metasomatized Bla =. ; chloritized Bla =.; spilitized Blb =. ; chiori tized Blb = +); metasediments Blb =.Â. ; Rhyoli tes: RR = 0 ; Brn. = 0 N~bers refer to sarnples listed in Appendix V.

The three major alteration assemblages have already been,

introduced: spilitization, K-metasomatism and chloritization. Only a

few samples are truly representative end members of the three types,

and most of the basic rocks exhibit superimposed alteration assemblages

which are not easlly discernable in the field or, even petrographically,

and are often difficult to quantify. The distinction adopted in this

study was based on a visual estimate of the amount of al teration present

in thin section or, if the thin section of the same sample was not

available, the estlinate was made by comparing the major and trace element

geochemistry wi th known samples taken nearby.

•

(

(

- 50 -

For clatity, geochemical data from the metavolcanics (Figs. 4.6

and 4.7) and the rhyolites (Fig. 4.8) are plotted separately. ,

4.3 Metavolcanics (Table 4.1)

The least altered met~volcanics are the spilitized rocks which

were only"locally affected by subsequent chloritization and K-metasomatism.

The addition of silica is a consequence of spilitization. Silica is

dissolved in fluids in sorne parts of the geothennal system and

precipitated in others, increasing the Si02 content of the original

basaIt and generadng a calc-alkalic trend (MacGeehan, 1979; MacGeehan

and MacLean, 1980a). This feature is observeq in almost aIl the

spilitized rocks. In fact, the intensely spi1itized samples at Radiore

disp1ay regular changes in elements with increasing silicification that

mimic calc-alkalic trend (Figs. 4.6 and 4.7).

In the absence of relative1y fresh volcanic rocks, geochemical

trends were constructed using the average values for elements taken from

B2 basaIt ~cGeehan, 1979) which should have the closest values ta BI

, (the average sulphur value of 917 ppm of B2 basaIt is taken from "

Pasitschniak, 1981). However, as shawn by MacGeehan (1979)~ there are

variations between flows which may have sorne influence on the slope of

the line constructed for BI in Figs. 4.6 and 4.7 and ultimately on the

interpretation of the geochemical changes during spi1itization. In this

process almast aIl elements appear ta have been either added ta or

depleted fram the original rock. Only K, Ti, and P show a more low slope

of their lines, but.this may be partly due ta the scale used in presenting

the data. This is not surprising, as under intense water/rock interaction,

- 51 -

Table: 4.1

Major and Trace Element GeochelRlstry o~ Metavo1camcs (B1a and B1b)

B1a Blb

r Ch10Tltized SpllltlZed Spll1tlZed AlteratIOn Ch1ont1Zcd Spllitized K -metasomatlsm

}

;0..,.-' ' RAD 100 RAD 43 RAD 78 , SAMPLE RAD 44 RAD 60 RAD 80

- 55. Dl 58.53 68.82

- 0.90 1.63 0.85

14.19 12.73 11.86

2.41 3.15 2.35

7.41 11.55 5.5B

11. B3 3.24 2.62

51°2 , 52.71 62.43 62.43 r ,

TiOZ 1.49 1. 24 1. 33

A1zÛ3 14.93 13.05 10.30 1 3.02 2.76 2.85 Fep3

FeO ~ 13.71 9.14 9.43

MgO 12.38 6.36 6.46

CaO 0.55 2.00 0.73 5.08 4.28 2.18

2.48 3.86 3.78

0.67 0.82 1.}9

0.03 0.20 0.16

19 21 53 ,

NazÛ 0.83 1. 81 2.39

KzÛ 0.37 1.10 3.85

P205 0.03 0.10 0.23

Rb ppn 17 27 318 \

71 , 118 100

37 78 72 Sr IL 65 65

Y 42 59 100

Zr 89 218 327 77 240 354

Nb 7 13 19 9 11 20

Zn 90* 72* 95 S9 68 32

Cu 18* 89* 125 18 2S 67

NI 15* 23* 39 35 11 9 /

Mn 1929* 1117* 1445 1014 1612 441

Cr 264 * 20* 68 41 3 6

S 66' 278" 162 66 160 154

FeO* % 16.43 11.62 13.00 9.58 14.39 7.70

NORM.An 26.52 32.72 9.54 54.37 31. 45 23.42

NORM.C 12.24 5.48 1. 42 0.22 0.00 0.12

44.79 33.71 18.45 -COLOR INDE~ 58.26 34.65 35.51

* :: Average of two analyses

~-t '

!

/

, "

>.

" ~

1 1(

1

f i.

i 1

, .... ,~

1

,/

Fig. 4.6

( \

- 52 -

B1a B1b

AI'O;:~ .~~ .. ~~ ______ ~~ __ ~~1.~ ________________ __ Il -. •

MgO • • • . * * • . ... - \-

FeO* ~ .. ~ . j~ t· _~~

,.0, :1 *.. .. ·1 * , • . •• ....

Cao i~.j",---_ NI20 :f. .. t, . ~ ..,.w..-.... .--·.:..-.~.:-1.r·-"'"1.rt-:

:L ~ _ : ,~ l-....... ; ...... ~. =tC·:I;:' ::::::!:::.

:L.. t. .L:. . .. • 1\05 .th _ •• t •. Li. : ' ..... ., i SI " .. Il Il .. ..

Si02

(wt't.) VS major oxides Cwt'!.) of altered metavolcanics: Bla and Blb. The symbols: += spilitization;. = K-rnetasomatism; .= chloritization ce = rnetasediments, slightly K­

metasoma.tized) * = mean composition of least altered B2 basaIt QMacGeehan, 1979). The line is the best fit of spilitized Ct) rocks and fresh B2 basaIt (*) See Appendix III-c FeO* = FeOtO.9 FeZ0 3

\

\

r

:;r ..

-r

t ~ , ,

1 r ,

:

Fig. 4.7

\. ! \ (' , ,

- 53 -

B1a 81b

Rb

Sr

y

Zr

• • .. Nb •• -, • • • •

Ni

... Cr

S • •

• Si02

SiOZ (wt%) vs trace elements (ppm) qf altered metavolcanics: Bla and Blb. The symbo1s: += spilitization;. = K-metasomatism; .= ch1oritization (.= metasediments, slight1y

K-metasomatized) * = mean composition of 1east altered BZ basaIt OMacGeehan, 1979; Rb-Sr-Y-Zr-Nb courtesy of Dr. MacLean). The 1ine is the best fit of spili tized Ct) rocks and fresh BZ basaIt C.), see Appendix III-c. Sulphur value for B2 is 917 ppm (Pasitschniak, 1981).

;

~

t ( f

c

L~~ __ ._

- 54 -

.p

almost a11 the elements become mobile (the literature is constant1y

reporting that the so-called "lmmobile elements" are effectively mobile).

The major geochemica1 changes are decreases in Ca, Fe, Al, Sr, Ni, Cr,

Mn and S and increases in Rb, Y, Zr and Nb. Na and Mg disp1ay an

ambiguous trend.

A departure to the linear-trend is explained as being caused by

subsequent alteration events.

K-metasomatism produced drastic changes (RAD 80). In addition to 'ft't ,t

potassium, other elements have been added: Rb, Y, P205' Sr, Ti, Zr, Nb

and S. The reason that the sulphur data show no significant increase l'

is that large pyrite grains were carefully avoided dunng sample

preparation. AltnnmUID seems to have also been leached. The presence

of do'~omite and minor calcite suggests that COZ-rich fluids were plA of the alteration. COZ-rich fluids are reported by Hynes .(1980) to be

extreme1y effective in mobilizing Ti, Zr and Y, believed to be relatively

immobile, and thus may acçount for the abrupt changes in the other

elements accampanying K-metasomatism.

Chloritization is interpreted ta have been ,*he last pervasive \

alteration event in the mine area. Mg is the main e'1ement taken up from

circulating fluid during this alteratiorr. Compositional variations of

chlorite were not determined but, petrographically, sorne âifferences in

refractive indices and interference colours were noticed. Ca and Na

were strongly depleted during this phase while Fe had an opposite /

behavior being enriched in Bla and depleted in Blb. In this respect

sample RAD 100 is enlightening: in spite of the strong chloritization

i t has a low iron content, high ~gO and practica11y no opaque mineraIs,

1 " ,

\

" ~

i ~

j

".

t

- 55 -

which suggests that chlaritization here was mainly a magnesitml enriching

event.

4.4 Rhyolites (Table 4.2)

Petrographically the least altered rhyolite is sample RAD 67'

(Table 4.2). Although texturally it seems ta have its primary chemistry 1

intact, the low silica content classifies thlS rock as daclte.

This is certainly due ta the high iron content, exceptianally

high fo~ OCR or for any rhyolite. It has already been noted that field

relationships indicate that it could be a shallowly emplaced sill or "--'

dyke, but due to the tlllcertainty it is considered as BeR.

The rhyolites cannat be monitored on the basis of alteration

assemblages as outlined for metavo1canics: in fact the al tera t ions .. ha?

Many elements Ce.g.,: Na any left no definite imprint on these rocks.

Ca), if ccrnpared ta the average content of fresher rocks (Fig. 4.8)

appear ta have been depleted but it is impossible ta -attribute such

variations ta one or another alteration if there is no def~ite mineraI

assemblage that. 'characterize the samples.

K-metasomatism has pervasivel~ affected the Raqiore rhyolite, in

particular the clastic parts (tuffs or metasediments) . It was not always

possible to distinguish between altered rocks derived fram massive

rhyolite or fran metasediments and tuffs; however, samples with low

silica and high AlZ03 are likely ~o be metasediments. Tt is not possible

ta establish geochemical trends wi th this type of rock as the original

sediments might have had a composition as variable as the present rock.

~

! -

~ , t -~ ~~

" , ,"-< :l ~,

" ~ fj , .~

': fi ..

(j

1

() r' • . , ..........

~

-~~

\ ,

•

~\. -

.K

- 56 -

Tabie: 4.2

~Jor and Trace Element GeocheuustX}' of Rad)OTe CRE) and Bell Channel _1 jte (OCR)

RR OCR

SAMPLE RAD 662 RAD 62 RAD S3 RAD 67

3 RAD 40

SiOZ ~ 43.54 .;'3.15 79.71 62.74 73.57

T102 2.47 0.74 0.37 0.73 0.44

A1zÜ3 21. 88 11. 01 6.53 1 3.98 2.25 1.88 ~e203

FeO 7.58 3.03 6.47

10.34 8.63

2.26 1.95

16.18 6.69

MgO 12.60 6.39 4.32 1. 06 2.06

CaO 1. 07 0.39 0.18 1. 58 3.39

Nap 2.10 0.44 0.21 4.16 1.82

KzD 4.72 2.63 0.32 0.82 1 1.10

PPS 0.05 N.D. N.D. 0.12 0.34

Rb PIJIl 117 54 10 26 28

Sr , 48 "

11 3 7e) 124

Y 58 68 12 S4 57

Zr 216 368 100 289 318

Nb 22 20 7 9 12 ~

Zn 97 41 7g 31 43

Cu 21Z 18 7S9 lS 55 "

l'i Ni 11 64 9 14 9

Mn 458 280 255 282 385

Cr 55 N.D. N.D. 23 N.D. , 5 359 284 348 81 728

FeO* \ 11"'.16 5.06 8.16 19.01 8.45-10-

NœM. An 21. 91 j2.42 33.45 16.71 44."06

NORM.C 11,49 6.79 5.51 0.02 0.00

COLOO INDEX 37.74 23.06 23.90 33.94 19.78 1

1 Fe203 = Calculated as Welght Percent T102+1.5\ N.D. = Not Detected

2 Metasediments

3 Qz-eye rhyolite

..

... - 57 - ~.

(j r 10

0

B l1li 0

A1,o. 0

0 0

Q <1* • .. 0Q • 0 , , , , ; a

~o //

, , )'

" 0 ".

1 Sr

0 • 0 a . , ,fi , , 1 , 9 , ~

• a

1c

FeO 0 <0 y

°0 0 0 @ ~ 8 r:I< a

a , _ 0

Zr a 0 0

.'4w.: 0 1 a

"'0 ,,0 ~, .... -' .' 0 ° a 0 0 0

~o 0

0

~o 0

CIO fil. 0 00

0 * a 0

0 0 • a 0 , , , 1 q

L 9 0 * '.

•• 0 0 M!- O 0

0 0 00 00

0 0 ij i 8, 1 1 ,

l 0 0 0 Cr

0 0

K.O 0 , , , ; .

0

l 0

* 00 S 0

0

1 a

c9

'" 'b

~o !

, , , 9 , <9 0

no. 0

0\ 90 f 1 MIl

~1o 0

0 0 a 0 0 0,0

0 0 li O{ Q: , , JI ~ Il

... SiG. SiO.

l'

, "

L 1

Fig. 4.8 SiO~ (wt9,,) vs major oxides Cwt'!,) and trace elements Cppm) of diore (RR) and Bell Channel (BCR) rhyolites, and Radiore

"" rhyolite metasediments. The symbols: 0= RR; 0- BCRO RR metasec:liments; * = mean

0 composition of least altered BÇR or NR (MacGeehan, 1979). " c .... ,~

~ ·f

'il

J 1 ! J ..... -- ~_ ... _".--,~-... ..,.

(

- 58 -

4.5 Geo'chemistry of the Intrus ive Rocks

Sharpe (1964, 1968) interpreted the si11s to be high level sub­

sidiary intrusions of the Bell River Comp1ex. MacGeehan (1979) showed

that the basalts and the intrusive counterparts had many cornmon

characteristics: both are derived from iron-rich tholeiitic magma

• (essentially comagmatic), crystallized the same mineraIs, and continued

to fractinate in the same manner during crystallizatian.

Geochemical plots confirm the tholeiitic trend of most of the

intrusives (Fig. 4.9), with the exception of the gabbro-diorite dykes

which display a distinct calc-alkalic affinity. This will be briefly

analyzed below.

A1z0l ..... --------~-"'-------~MgO

Fig. 4.9 Jensen (1976) cation plot. It discriminates between ca1c­alkalic and tho1eiitic rocks. The symbols: • (Gabbro­Pyroxenite), • (Diabase), 0 (Gabbro-diorite), • (quartz­diorite), ~ (Granodiorite).

j

r, "-, 1

)

\ \

'.

! 1 ,-

(

\

- 59 -

The terminology for the rocks is derived fram the RI-R2 plot

proposed by De La Roche et al. (1980) for the classification of intrusive C"

rocks (Fig. 4.10).

Fig. 4.10 """

Classification grid of plutonic rocks and the currently used nomenclature. The diagram is after De La Roche et al. (1980). The symbols: • (Gabbro-Pyroxenite), • (Diabase), 0 (Gabbro­diorite), • (quartz-diorite), T (Granodiorite).

4.6 Gabbro-Diorite Dyke

Field evidence shows that the gabbro-diorite dyke was probably

one of the last intrus ives emplaced at Radiore. Although rocks bordering

the dykes are hydrothermally altered, there is no evidence of direct

inv~1vement of the dykes in any major alteration events. There is

evidence in the dykes of a weak spilitization and, loeally, of quartz-

epidote veinlets and patehes (bleached zones) similar to the ones

described by Harrigan and MacLean, 1976, for the gabbro-dyke: but other-

wise the ehilled margins and the core oE the dykes retain their primary

texture.

c:.

1 .....

- 60 -

~ ~

. AlzOa :i Cl I:l

Efl

:~ • 0

FeO* o °CfJ

MgO j O~

:~ 0

CaO 0

o~

NazO j ofèfèJ <>

:) 0 KzO 0 0

B

TIOo j ..., OIIltJl

j F\O. o~

.'. .', l'

~ " SiOt

Fig. 4.11 SiOz (wt%) vs major oxides of gabbro-diorite dykes.

~ 0

lm

Rb 0

9

'~ DO

Sr o:J

9

Y 3 OarRJ

:1, Zr tShD 0

Nb j olIlftJ

j 0

Ni o 0

cp •

Mn j 0

cP ~g

~ 0

. S 0 0

2 J-

SIOz

(wt%) and trace elements (ppm)

1 ! '

1

(; \

- 61 -

The geochemistry shows no major changes (Fig. 4.11). Only Ca, K,

Rb, Sr and S appear ta have slightly departed from their magmatic com-

position and these elements are the mast mobile and easily released

under conditions of water-rock interaction.

There is no suitable interpretation ta explai~;the ca1c-a1kalic

nature of these intrus ive (Fig. 4.9 and the plots, not shawn, of wt%

A1Z03 vs An normative compbsition after Irvjne and Baragar, 1971,

Ti/IDD x Zr x Y/3 and Ti vs Zr after Pearson and Cann, 1973) except by

suggesting a separate magmatic event, but calc-alka1ic rocks are not

known in the area. It is therefore propased that these rocks were

derived fram a deep seated magma chamber tota11y unrelated ta the one

which produced most of the volcanic rocks at Matagami.

t 1 • ,

" - 62

J

CHAPI'ER 5

'~\

f \

J \

PETROGRAPHY mr- GEOCHEMI STRY OF 1HE OREBODY

J 5.1 \

f

Introduction

In, light of evidence that metals are leached from the volcanics \

to forro massive sulphide deposits QMacGeehan and MacLean, 1980b) the

geochemistry of the ore was studied to establish the behavior of sorne

elements other than Fe, Cu, Zn, and S, that concentrate in the orebody. J

The mineraIogical composition of the massive sulphide Iense and

the gangue mineraIs associated with sulphides were investigated through

petrographic and qualitative microprobe analysis .

The geochemistry of the massive sulphide ore was carried out by

analysing 16 elements (Cu, Zn, Au, As, Ag, Cd, Sn, Pb, Bi, Cr, Co, Ni,

V, Mo, W, Mn) from sarnples with different arnounts of sulphide. The bulk

ore includes sulphides and silicates, 50 that geachemical values

correspond ta the SUffi of the element concentration in the gangue and

sulphide phases.

5.2 InternaI Structure of the Orebody

The internaI structure of the massive ore was studied by mapping

the backs of the drift on mine level No. 1. The observatIon of the ore

was difficult because of high backs in the mine level. The ore was aIs a

often obscured by large patches of crust formed from a mixture of carbon

dioxide, unburned diesel fuel and dust that reacted with the sulphides

and was impossible ta remove by washing.

The massive ore lense can be subdivided into two zones:

..

;<'

i j "

, )

1 • 1

(

•

- 63 -

(1) Basal Zone: It is underlain by massive rhyolite (RR) and locally

by metasediments or tuffs (RR) but no clear contact between the

two units (RR/ore) is observed. At the base, it is very siliceous

(±SO% quartz and±20% silicates) with sulphides becoming the major

constituents towards the top (80% comb1ned pyrrhotite, pyrite and

chalcopyrite). Its thickness is a maximum of 2 rn in the center

and it gradually thins laterally to a tenth of a metre. At the

eastern end of the lens, the basal zone is missing and a vesicular

massive rhyolite (RR) is directly in contact with the upper

l,

. mineralized zone. Chert, metasediment or tuff and chloritized

rock fragments, sorne of which are irregularly shaped with the

largest dimension up ta 50 cm or more, are intermixed with /' silicates and sulphides (Map 5). The ,presence of such large

f exotic fragments in the ore and the ~otal lack of banding are

clear evidence of re-working of t~suIPhides soon after primary

deposition.

(2) Upper Zone: This is massive banded ore which forms the top and

major part of the orebody. lts maximum thickness in the center

is approximately 5 m, but it thi~s laterally and interdigitates

in layers (up to a few centimeters thick) with the host rock.

The contact with the basal zone lS sharp. The banding, which

characterizes this unit from the zone below, is mostly defined

by pyrite-rich layers separated by undulated stratigraphie

contacts marked by the accumulation of chloritized rock fragments

(Plate 6.2) ranging fram Inicroscopic size ta larger than several

t

c .~.

5.3

- 64 -

centimetres and concentrated within different bands. The bands

can on1y be traced for a few metres after which they fade out ta

appear again severa1 metres away. Neverthe1ess the continuity

of the single 1ayers is not correlatable at the map scale (1:50)

as they thicken and thin rapidly. The thickness of the bands

varies from 10-15 cm to 50 cm or more. Cross-cutting relation-

ships can be interpreted (Plate 6.3) but concrete proof of a

syngenetic character of the ore has never been fully acquired.

The main sulphide mineraIs are pyrite, chalcopyrite and

sphalerite. These often occur in smal1 monomineralic layers of

1-10 cm thick (Pl~te 6.4) with 1imited 1ateral continuity. At

the far eastern end of the lense a very distinctive band, made

up mainly of large pyrite crystals, overlies the massive vesicular

rhyolite (RR) and grades into chloritized metasediments ~p 5).

Ore and Gangue Mineralogy

The ore and the gangue mineraIs in the orebody show a strong

zonation with pyrrhotite, pyrite, chalcopyrite and silicates occurring

in the basal zone and pyrite, chalcopyrite, spha1erite, magnetite and

silicates predominating in the upper zone. Sphene, Fe-Ti oxides

(ilmenite or ulvospinel), rutile, apatite, dolomite, ankerite and

calcite are occasionally found in both zones. The increase of sphalerite

in the upper part accompanied by a drastic decrease of pyrrhotite is a

weIl documented difference between the two zones. The approximate

percentage of each mineraI in each zone is as foIfOWS (estimates made

from po1ished sections):

\

i, ,

(

\

(Basal Zone)

Pyrrhotite 30 .~ 70%

Pyrite 20 - 30% 1 1

Chalcopyrite l - 20%

Sphalerite trace

Magnetite

Silicates 5 - 70% ,1 1 /

1 1

65

1 1

1 /

/

I­I

. '-..,/'

y (Upper Zone)

o - 5% 50 - 70%

1 - 20%

f!- 20%

1 %

5 - 20%

This type of zonation indicates that the pyrrhotite is a primary

phase and not a metamorphic effect. McDonald (1967) and Vokes (1969)

have determined that under high temperature and pressure it is possible

for pyrite to be converted to pyrrhotite plus sulphur, but ,~t Radiore

the drastic change in the amount of pyrrhotite between the two zones

rules out this interpretation. Furthermore, there is neither evidence

of local addition of sulphur nor replacement of pyrite by pyrrhotite.

The simplest interpretation is that the variation is the result

of different depositional chemistry caused by a sudden increase in

sulphur content. The major difference in the ore mineraIs between the

two zones is that spha1erite is present with magnetite in the upper zone.

No changes in the type of silicates or carbonates were observed.

The geochemistry of the 16 elements analysed in the ore does not

show any significant distribution differences between the two zones

suggesting that, beside sulphur and zinc, the other elements have not

changed substantially.

The following mineralogical description refers to the mineralogy

of both zones.

Among sulphides, pyrite usually occurs as large cubic porphy­

roblasts (Plate 7.1), often, poikilitically enclosing grains of adjacent

(

- 66 -

silicates and other ore mineraIs. When the ore is composed mainly of

pyrite the crysta1s are bounded by subhedral curved faces and forms

single grains at 1200 tripl~ junction. Pyrite occasiona1ly shows brittle

fracture/suggesting that deformation was localized and probably related

to faulting rather than to reglonal metamorphism.

Where pyrrhotite is the major sulphide, it forms the matrix to

pyrite and chalcopyrite; when the latter is abundant the opposite is

observed. Pyrrhotite mostly occurs as anhedral grains or elongated \

curved grains (Plate 7.2) with a preferred orientation and separated by

elongated silicate crystals parallel to the orientation of the sulphides.

The curved form of the mineraIs in this probably resulted from local

deformation as only in this section pyrite shows brittle fracture.

Where pyrrhotite is an accessory ore mineraI it usually occupies

interstitial positions or forms inclusions within other sulphides.

Sphalerite is mostly associated with chalcopyrite and pyrite; it

displays mutual boundaries with the former and is the matrix ta the

latter.

Chalcopyrite behaves in much the same way as pyrrhotite, and in

sections rich in chalcopyrite it commonly forms the matrix to aIl the

other sulphides. Chalcopyrite displays a similar orientation ta

pyrrhotite but, due to its higher ductility, tends to completely wrap

around silicate crystals and other orc mineraIs ta form isolated crystals

in a chalcopyrite groundmass (Plate 7.3).

Magnetite is the most abundant oxide gangue mineraI. It is found

in euhedral form and rarely as sub-rounded or irregularly shaped grains.

When weIl crystallized it appears as porphyroblastic overgrowths on

1

,

j 1 i ~ 1

i 1

1. 1

1 ,

J

t l

f

f l 1 r

\ •

(~,

(~!

- 67 -

earlier magnetite in a sphalerite and pyrite matrix.

The main gangue mineraIs are anthophyllite, tremolite-actinolite,

biotite, chlorite, and quartz. The amphiboles forrn euhedral crystals •

0.1 to l mm in length (Plate 7.4) disposed randomly or grouped into

layers within the ore. Biotite and chlorite are also irregularly

distributed. Quartz grains forrn inclusions within the opaques or,

sometirnes, in association with other silicates they form thin selvages

around sulphides.

MineraIs of the tremolite-actinolite series are the most abundant

silicates and from qualitative microprobe,analyses they are mostly

ferro-actinolite. Carbonates (dolomite, calcite and ankerite), Fe-Ti

oxides (ilmenite or u1vospinel), rutile, sphene and apatite are

occasionally found.

In sumrnary, the elements associated with sulphides are Fe, Cu

and Zn, while Fe, Ti and Si forrn the oxides and Ca, Fe, Mg, and Si form

the silicates. Only chlorite and biotite have in addition Al and K-Al.

Carbonates are found in only a few samples and their amounts are

estirnated as less than one percent. The bulk composition of the ore-

body is essentially made up of Fe-Zn-Cu-S-Mg-Si and subordinate amounts

of Ca-K-A1-Ti-COZ. ,

5.4 Texture and Composition in Relation to Post Depositional Processes

The texturaI relationships between the sulphide, oxide and

silicate phases are interpreted to be of metamorphic origin and the

paragenetic sequence is rnuch the same for mineraIs found in similar

volcanogenic deposits (Rockingham and Hutchinson, 1980).

,

l f 1

!

1 l ;

t \

1 ( ,

c - 68 -

Textures previously considered Ce.g., mineraIs forming the matrix

ta other euhedral mineraIs; intergrown metamorphic mosaic exhibiting

triple grain junctions at approximately 1200) are recognized as being

due to recrystallization (Vokes, 1969) and the observed paragenetic

arder attributed to the tendency of euhedral mineraIs to develop

idiornorphism following the crystalloblastic series proposed by Stanton

(1964). For example, the observed idiomorphism of magnetite and pyrite

is contrasted by the anhedral form of sphalerite, pyrrhotite and

chalcopyrite which exhibit mutual intergrowths of metarnorphic crystal-

1ization.

The mineraI 1ayers are probably not re1ated to metamorphism.

Vokes (1969) interprets that ore bahding is an original mineraI feature

general1y preserved after metamorphism. Barton (1970) argues the

opposite and believes that sulphides, due to the different rate of

reaction during metamorphism, can tell us nothing at aIl about the

environment of initial deposition. However, in the writer's opinion

tf(e bands observed at Radiore reflects more a primary feature not com-

p1etely erased by metarnorphic crystallization.

A1though primary textures have not been identified, su1phides

and magnetite are interpreted to have re-equilibrated through a sequence

of texturaI changes from simi1ar mineraIs deposited frorn ore-bearing

solutions. Silicates, carbonates, rutile and quartz went through a more

camplex history. Aftabi (1980) has presented an interpretation of the

evolutionary stages of te~~res in ores at Garon Lake based on sulphide

and silicate relationships, but tr is beyond the scope -of-this study to

- --_ ... -. -----_._ .. _-----...,--_.---- -

.'

{

1 ,

(~

1

i 1 •

'--

[ pursue the discussion along this line.

The bulk composition of the ore indicates that apar from the

sulphides, the silicates are by and large Mg-Fe-rich ph~ses. The

• presence of alumina-silicates in the ore is readily explained by the

presence of a large proportion of chloritic fragments mixed with clay 1

rnaterial suggesting a reworked stage of the ore before final deposition

in the repository basin.

Mg-rich phases have been observed at Mattagami Lake1mine in which (

talc is the main mineraI present in sediments'within or close to the ore

(Roberts and Reardon, 1978), ,and talc is also found in mines in the

Noranda and Joute! areas (Costa et al., 1980). Sirnilar precursors have

been invoked by Aftabi (1980) ta explain the Mg and Fe-rich actinolite

in the ore at Garon Lake mine.

In conclusion, petrographic and mineragraphic evidehce seems to 1

exclude ore minera! assemblage changes by external fluids during'post-, depositional processes. This means that the entire orebody has reactetl

as an isochemical system during regional metamorphosism.

S.S Distribution of Elements in the Sulphide Ore 1

Multielement studies on ores have usually been neg~ected by 1

researchers who have focused their attention rnainly on th~ geochemistry

of single mineraIs (e.g., pyrite, chalcopyrite, etc.) and !rocks.

A review of the literature on the subject of minor lelements in 1

massive sulphide ore was compiled by Mercers (1976) .and sHows that 1

studies have only~een-made on a limited number of metals; the available . Soviet Iiterature offers Iittle or no contribution to the subject.

't

'} "~

1 1 ..

•

(

,.

- 70 -

The seleqion of Au, Cu, Zn, As, Ag, Cd, Sn, Pb,' Bi, !

MO, Co, W and Mn is by no rneans complete, other e1ements could be added

and this is part of a separate research program. The main goal was ta

.deterrnine the mu1tielement composition of the ore and ta establish

relations between concentrations of the elements in ore and wall-rocks

fram which they are presumed ta have been leached.

(1) Which of the 16 elernents are concentrated in the ore and w11ith

-\1 are not.

(2) If any of the concentrated elements ln the ore could be grouped

by means of showing constant enrichment 50 that this cou1d suggest

ùniform behavior. ,

(3) Theorize whether the present situation justifies the above findings.

It is evident that in arder to do 50 it is :important ta know the

concentration of these elements in fresh or relatively unaltered rocks.

It has been emphasized .early in the study that BI basaIt (MacGeehan, 1979)

of Bla metavolcani~s (this stucly) rarely outcrop and aImost aIl the , (

samples col1ected show a high degree of a1teration. Hence, values of

the 16 elements relative ta fresh rocks have been derived either fram

,B2 basaIt QMacGeehan, 1979) or frorn averages values in the Ilterature.

The enrichment factor is then calculated as the ratlO of the mean element

content of the massive sulphide ore compared to that of the unaltered

rocks taken as the source of the ore material .

. The mean values of sorne elements chbsen ta represent the average

rock value at Matagarni are assumed ta be correct within a reasJnable

error. However, gold deserves sorne discussion. The justification of

choosing 0.6 ppb Au compared with the ,average gold value of 17 ppb

c

(

) "" .. y/ .' ~, 'f~ ' ...

- 71 -

reported for basaIt (Boyle, 1979) is based on the evidence that rocks at 1

Matagami are low-potassium,tholeiites QMacGeehan and MacLean, 1980a)

closely resembling mid-ocean ridge basaIt which have a reported gold

content of 0.6 ppb (CJOttfried et al., 1972). It is evident that the

difference is one arder of magnitude WhlCh would result in a drastic

change in the enrichment factor. It is feit that for the present the

value of 0.6 should be maintained.

The chemistry of the 16 elements in the massive ore is presented . in Table 5.1. The mean composi tian. of each element in the orebody and

the relative value in the unaltered rocks together with the enrichm~t , .'

factor computations are listed in Table 5.2.

The concentrations of Cr, Ni, V, Mo and W in the ore show high

percentages of values (e.g., Ni, 95%) belaw the detection limit. The

enrichment factor was camputed by considering that the true mean value

.... ', ,

lies between the detection l:imi t and a number close ta zero. Sn and Cd

have instead 10% and 50% of the values respectively below detection limit,

(Barbier and Wilhelm, 1978). Elementary statistics (Table 5.3a) and

correlation coefficients (Table 5.3b) for Au, Cu, Zn, As, Ag, Cd, Sn, Pb,

Bi, Co and Mn were computed using the statistical program package

(STATPAKj at McGill University. Data for the remaining five elements

are unsuitable for.statistical treatment. An HP-67 , programmable pocket

calculator, was used to construct histograms (Fig. 5.1), and diagrams

of two variables (Fig. 5.2) showing the correlation between the variables,

the coefficient of determination (r2) and the regression line (log y ~

a + log bx).

"­, \

----_-.:...._----=------_. -_.- --. ~

,..,

-

." ... .....,. ... ..,... ~ - _ ....... "' .... -., .............. ~)-_ .. ~ ..... - .... ""

•

Table: 5.1 ~

Trace Element Geochemistry of Massive Sulphide Ore (ppm)

SAMPLE Au* Cu Zn As Ag Cd

RW 1 76 4800 150 30 6 <1

RAD 2 64 390 65 32 3 <1

RAD 7 39 2370 210 12 4 <1

• RAD 12 240 c 24000 30700 75 13 36

RAD 13 2S 11400 97 2 3 <1

RAD 14 130 2580 168000 57 12 240

j RAD 17 140 2040 10600 110 Il 14

RAD 18 63 107000 830 lS 6 <1

RAD 22 210 13600 100 140 18 cl

RAD 23 310 56000 5800 32 5 S

RAD 27 37 13700 150 47 5 cl

RAD 29 79 720 191000 58 3 320

RAD 32 120 36400 6300 22 8 6

RAD 33 120 35400 1020 43 8 <1 - ,

RAD 34 140 64000 210 63 9 <1

-RAD 35 100 115000 4200 37 7 6

RAD 36 280 14200 43000 100 16 70

RAD 37 460 2240 36 62 13 <1

RAD 38 230 20900 35100 79 14 48

RAD 39 22 185000 1690 4 9 4

--

. - not determined ....

* ppb

Sn Pb Bi

5 28 .6

<3 20 .7

<3 20 2.1 200 24 2.1

15 28 1. 0 .

60 24 8.0

15 20 4.4

45 24 2.9 25 44 9.9

25 32 2.1 8 32 .7

70 28 .5

45 24 2.1

45 ::11 1.7

10 24 6.5

30 16 2.5

520 16 4.4

5 28 8.0 40 16 1.7

30 52 6.5 ,

----- -- ----- - ~--

Cr Co Ni V

20 400 15 40

20 260 <5 <20

< 20 380 <5 20 < 20 470 <5 <20

<20 llO <5 <20

- 197 <.5 20

<20 170 <5 <20 -

<20 390 <5 <20

- 730 <5 <20

20 280 <5 <20 - 490 <5 20

<20 150 <5 < 20

<20 130 <5 <20

<20 430 <s <20

<20 380 <s <20

<20 190 <5 < 20

<20 230 <s <20

<20 520 <5 <20 <20 150 <s <20

20 110 <5 20

----~-- t..-!- .. ~-

-~

"

~

\

~. '»(\~~1

~

Mo W Mn

8 <1 220

<2 <1 70

<2 1 560 1

<2 <1 160

<4 <1 300

<2 <1 100

<2 <1 170

<2 3 280 f ,

<2 3 140

<2 <1 170 <2 1 170

<2 .<:1 100 1

<2 <1 90 1

<2 " 2 200 1

<2 <1 140 <2 2." 280

<2 . <1 330 1

1

<2 1 80 1

<2 <1 150

<2 2 70 1

/

~ • 1

1

1 • ~

,., > -t. ""., ';1 .... ~ •

Tah1e'S.2

- 73 -

and in Una1tered Rocks ent Factor ComputatlOn

MASSIVE SULPHIDE ORE: MEAN VALUE OF THOLEIITIC ENRICHMENT ELEMENT X = MEAN (ppm)

BA SALT AND BASALTIC ROCKS FACTOR FROM THE LITERATURE (pprn) ORE/ROCK

,~

t Au 144 (ppb) 0.64 (ppb) 240

;"Cu 3.56% 1061 (105 2) 336 (339) ,

108 1 (99 2) . Zn 2.50% 2;1 (252)

Ag 9 0.342 26

As 51 2.36 22

Cd 38 \ 0.1l 5 (0.28 7) 345 (135)

Sn S9 " 4.82 12

Pb 26 <21 (4.8 2) >13 (5.4)

Bi 3 0.258 12

Cr** (Ô -(20) 1461 (256 2) <0.137 (0.078)

Co 308 61 1 (38 2) 5 (8)

Ni** (0 -'5) 1021 (162 2) <0.049 (0.031)

V** (0 -(20) 2271 (385 2) <0.088 (0.051)

Mo** (0 -(2) 1.410 (*0.6?3) < 1.4

W** (0 -0) 19 (*1?3) <1

Mn 189 21381 (0.143%) 0.088 (0.135)

1 Mean composition of B2 basaIt, Hatagaml (MacGeehan, 1979).

2 Weighted mean chemica1 cornposi tion of tho1eiitic basalt by series in Superior Province, Table V, (Goodwin, 1977).

3 Analysis of BM international standard, (Abhey, 1980).

4 Table 79-E-l, low potassium tho1eiitic basaIt (Gottfried et al., 1972).

5 Cadmium content of igneous rocks (NRCC).

6 Arsenic content of igneous rocks (Boyle and Johasson 1973b).

7 Table 48-E-3, cadmium content in a fayalite-ferrogabbro, Skaergaard (Vincent and Bi1efie1d 1960).

8 Table 83-E-l, bismuth in standard W-l diabase (Taylor, 1965).

9 Table 74-E-1, average·tungsten in rnafic rocks (Vinogradov, 1962).

10 Table 42-E-6, average of subrnarine basaIt Hawaiian shelf (Lisitsina et et al., 1975).

* Question mark reported in the original analysis.

** The true menn lies between zero and the detection l1mit.

\

( ) .~\

. ~. } ~ -.... ~, ,~

~ ~I(

(

f'""

'.

.. .... ~ "', -~ . k " .. ~, , ..

"

- 74 -

Table: 5.3a

Elementary Statistics

ELEMENf MEAN sm. DEV. STD. ERROR MAXIMUM MINIMUM RANGE -------Au ppb 144 113 25 460 22 438

Cu ~ 0 3.56 4.87 1.09 18.5 390 ppm 18.5

Zn % 2.50 5.5 1.2 19.1 30 ppm 19.1 'As ppm 51 36 8 140 2 138

Ag ppm 9 5 . 1 18 3 15

Cd ppm 38 86 19 320 1 320

Pb ppm 26 9 2 52 16 36

,Bi ppm 3 3 1 10 0.5 9

Co ppm 308 168 38 730 110 620

Mn ppm 189 117 26 560 70 490

Sn ppm 59 117 26 520 3 517

Table: 5.3b

Correlation Matrix

Au Cu Zn As Ag Cd Pb Bi Co Hn Sn

Au 1.000 -0.239 -0.024 0.513 0.622 -0.040 -0.100 0.407 0.309 -0.230 0.322

Cu -0.239 1.000 -0.269 -0.396 -0.074 -0.264 0,.394 ..,0.150 -0.224 -0.074 -0.089,

Zn -0.024 -0.269 1.000 0.168 0.024 0.996 0.090 0.051 0.323 0.237 0.201

As 0.513 -0.396 0.168 1.000 0.784 0.161 -0.065 0.482 0.381-0.213 0.358

Ag 0.622 -0.074 0.024 0.784 1.000 -0.011 0.059 0.697 0.317 0.208 0.454

Cd -0.040 -0.264 0.996 0.161 -0.011 1.000 -0.075 0.025 -0.323 -0.228 0.200

Pb -0.100 0.394 -0.090 -0.065 0.059 -0.075 1.000 0.409 0.232 -0.365 -0.269 -Bi 0.407 0.150· 0.051 0.482 0.697 0.025 0.409 1.000 0.327 -0.272 0.041

Co 0.309 -0.224 -D.323 0.381 0.317 0.323 0.232 0.327 1.000 0.052 0.087

Mn'" -0.230 -0.074 -0.237 -0.213 -0.208 -0.228 -0.365 -0.272 0.052 1.000 0.204

Sn 0.322 -0.089 0.201 0.358 0.454 0.200 -0.269 0.041 -0.087 0.204 1.000

Significant Correlations:

Positive Correlation

Negative Correlation

--------------------------~._--'---- - -~-

1. \

- 7S -

X= 144 ppb

Au S.113 " '-42 "

X=38'" Cu S-49'"

,- 1 8'"

ji- 2 5'" ln s- 55",

,- 20"

As

Ag

Sn

Pb

Bi

Co

Mn

JI. 51 ppm

s- 36 "

, - 14 "

x- 9 ppm

s- 46

,- 17 "

II- 59 ppm

S-111

1- 49 "

il- 26 ppm

s- 9 ,- 3.8 "

il- 3 ppm

g- 3 " ,- 11

lI- 308 ppm

g- 168 ,- 63"

il- lB9 ppm

g- 117 " 1 - 44 "

"

~ba.Sl l' .. ..

H

If

s •• tandard d.~la\ton 1- cta .. Int.rval

Fig. 5.1 HistograffiS. Data are computed from Table 5.1. p

l'

[

Au :

••• •

•

• 10

Ag

Cd

,-

76 .

log 1- 118 '097 log.

100

,'. 097

10

•

1000

".026

• • Au

•

•

•

• • • •

Jou. 1 09+06 .....

101~1--------~10----------100---------~-

As

log y • -290+101 log.

b~,--------------------1~0----------'00

Zn

\ Fig. 5.2 Graphie representation (log scale) of element-pairs with

good corre1ntion coefficient (Cd/Zn) and others with poor correlation coefficient (Au/Ag, AulAs).

•

(

'\

- 77 -

The presentation of the histograms illustrates an aImost constant

variation in form: aIl the distributions are positively skewed, and with

the exception of zinc, which shows a bimodal distribution, the rest

display a polymodal frequeney curve. The choice of elass interval was

eornputed according ta Shaw (1964) who suggested that the best distribution

is obtained by taking a class interval between one-quarter and one-half

of the standard deviation of the data. It is interpreted that the poly-

modal distribution is a true feature of massive sulphides but no lirnnediate

explanation can be put forward. The graphie presentation of the correlation

between trace elements (best represented on a logaritmic scale) shows

examples with pairs of vanables with a correlation coefficient >0.40.

In Table 5.3b and Fig. 5.2 linear correlationl between zi~c and

cadmium is evident while other pairs (e.g., Au/As and Au/Ag) show a more

randorn correlation. The relationship between zinc and cadmium is weIl

documented in the literature and is explaIned by the replacement of Zn

by Cd in the sphalerite lattice. Beside pyrite, pyrrhotite, chalcopyrite,

sphalerite, Fe and Fe-Ti oxides, other ore mineraIs were not encountered,

therefore the relationships observed in Table 5.3b and Fig. 5.2 can best

be explained by these elements occurring as minute grains of sulphosalts,

or as solid solutions in the major ore mIneraIs. Table 5.3b and Fig. 5.2

indicate that, except for Cd and Zn, these elements occur mainly as

sulphosal ts. A poor inverse. correlation, not readily interpretable,

exists between such pairs as Co!Zn, Cu/As and Pb/Mn and is shown in the

same table.

l Correlation of 1 indicates a perfect relationship hetween !wo variables, while -1 is an inverse relationship of one variable to the other. Zero indicates the lack of any linear relationship.

--------~------- ------- - -

.-~ ......

78 -

The enrichrnent factors are graphica11y presented in Fig. 5.3.

Go1d, copper, zinc, and cadmium have the highest (150-400) enrichment

factors. Si1ver, arsenic, tin, bismuth and lead have lower b~t sub-

stantial enrichment factors between ]2 and 26. Cobalt, molybdenum and

tungsten show little or no enrichments while chromium, nlckel, vanadium

and manganese do not concentrate in the ore.

It is important ta note that the average composition of gold in

the ore (144 ppb) obtained in this study is substantially different from

that reported fram the mill heads at the mine 0.009 troy oz/ton' (280 ppb) ,

whereas si1ver is aImost the same in bath, 0.25 troy oz/ton (8 ppm)

against 9 ppm of the calculated mean. The averages calculated for zinc

(3.56%) and copper (2.50%) exceed the values ohtained at the mine (1.34%

and 1.57% respectively), imp1ying that elements with large variances

require greater numbers of samples, or Iarger samples, ta obta1n reliab1e

mean values. In light of this conclusion Cu, Zn and Cd enrichment factor,s

may be smaller than those computed for Table 5.2, but this qepends on

the reliability of the measurement of the metai contents of the basalts

being 1e~ched. If Cu and Zn are recalculated on the mine averages the p'

enrichment factor for Cu is 148 and for Zn is 124. A comparison using

the mean values from this study and the mill-head assays is given ln

- Enrichment Factor - Enrichment Factor x '·x

Au 144 ppb 240 280 pnb 466

Zn 3.5M 231 1. 34% 124

Cu 2.50% 336 1.5n 148

Ag 9 ppm 26 8 ppm 24

...

"-

Î

(.

(

i /

.

100-::

0

. -

-"

O.1~

.01-

..

Cd Cu Au Zn

.

. ,

- 79 -

Ag As Pb il'

Bi Sn

Co

, Cr r

VMn f... ~,

Ni

Fig. 5.3 Enrichrnent factor plotted in order of decreasing values. Due to uncertainties of values, the arraws indicates directions in which enrichment factors are expected to plot.

c

t

- 80 -

The high enrichment factor of the rnill-head gold assays rnay be

true but it can also be the result of a cornbination of errors:

inaccuracy of gold deterrninations at the mine. (1)

(2) the basalts at Matagami rnay have higher gold content than

the average used in this study.

This illustrates how sensitive sorne of the enrichment factors are

to the srnall contents of the elements in the basalts, particularly when

they approach the detection lirnits of the analytical methods in use.

5.6 Metal Distribution

A camparison of the distribution of Cu, Ni and Zn between the

least altered basaIt, the rocks adjacent to the orebody, and the orebody

itself was carried out and is shawn in Table 5.5. Cu and Zn show a

consistent depletion fram the least altered through the more altered one,

the Bla metavolcanic, but is higher in the altered Radiore rhyolite and

in the ore deposit. Table: 5.5

Cu, Ni, Zn Concent~a~~on in the Least Altered

and Altered Rocks, and in the Massive Ore

Number of Mean values! in pprn Samples 1 Rock Type

Cu Zn Ni

B2 l Cleast altered basal t) 6 106 108 102

Bla metavolcanic (below the orebody) 6 93 79 30

Radiore Rhyolite 7 250 159 22

Massive Sulphide Ore 20 4.9% 5.5% 5

1 Values from B2 basaIt (MacGeehan, 1979). ~.

,1

- i

- 81 -

On the contrary Ni is continuously depleted. The low contents of Ni in "

massive sulphides lS essenLially a solubility effeet and probably also

V and Cr behave in mueh the same way. The obsèrved variations suggest

but do not prove a genetic relat10nshlp between the rnetals in the rocks

and the metals in the ore. Also the simllarlty ln the values of the

partitionlng coefficients of Cu, Zn, Cd and Au between the unaltered

rocks and the ore suggests again that a similar relationship exists. A

more convlncing dernonstration that the underlying rock have provided the

ore rnetals at the Garon Lake mine, Matagarni, was described by MaeGeehan

(1978) and MacGeehan and MaeLean (1980b). These authors identlfied a

large zone of hydrothermally altered basalts and deduced, based on the

best fit regression lines of major and trace elements using Si02 as the

independent varIable, that metals were leached from the basaIt ta form

the ore deposit. ThIS proeess irnplies that the metal/rnetal ratio of

these elements Ce.g., Cu/Zn) in the rock must refleet this metal ratio

in the ofe. If one applies a slffiilar concept, by using Cu, Zn, Cd and

Au values from Table 5.2, the correspondlng ratios show sorne analogy;

but again the true average of these elements, either in the rock and in

the massIve ore aught ta be establlshed with confIdence before the

validl ty of the model ean be assurned.

t

--

po

cpy

py

PLATE 6

6.1 Mineralized siliceou~-::~~~ sulphide (Basal zone). 1

Massive rhyolitl' showing large devit­rified perlitic texture with sul- .­phides (pyr i te - pyrrhot i t e -chalcopyrite) forming ln the ",strix and ln mirro-vp!nl ("t~.

Radiore Rhyolite.

o

6 2 Banded massive sulphide • (Upper zone).

Massive sulphide ore (pyrite -sphalerite - chalcopyrite) with large to small chloritized fragments paral­leI to hedd ing.

Radiore Massive ore.

6 3 Banded massive sulphide • (Upper zone).

Massive sulphide ore (pyrite -chalcopyrite) showing cross-<'utt1ng relationship (white \ine) within massJve ore; above ,it is slightly displaced by a microfault (black Une) ..

Radiore Massive ore.

6.4 Banded massive sulphides (Upper zone).

Almost monom1neralic layers of pyrite (py), chalcopyrite (cpy) and pyrrho­t ite (po) occasionally observed in the ore.

Radiorc! Massive ore.

(

, ) \

. 1. "'" , / ..

' ..

PLATE 7

7 1 WeU recrystallized porphvro-• blasts of pyritf.' (PY).

Space bet..,een grain boundaries ls filled by pyrrhotite (po).

Sample RAD 22, Massive ore. Plane light. Vie.., 2.2 mm aeross.

7 2 Elongated curved gra.;ins of • pyrrhotite (po) immersed in

Il silicate groundmass and textura1ly parallel to bedding.

Sample RAD 13. Massive ore. Plalle light., Vie.., 2.8 IIID aeross.

7 3 Massive chalcopyrite wrapped • around isola ted clustereil

euhedral crvstals of Ilctinolite.

Sample RAD 3. Plane light.

Massive o'e~ Vie.., 2.6 mm aeross.

L

7 4 Euhedral am~hiboles. (tremo­• lite - actinplite) dispE<rsed

randOlllly in massive sphaIer:lte.

Sam pIe RAD 14. Massive ore. Pl a nt light • View 1. 2 mm ac ross.

0>

1

1 f i i'

t

,

1 .1

(

\ 1.

..

)

CHAJ!fER 6

SEAWATER/ROCK INTERACTION: AN INTERPRETATI(l'J OF THE FORMATION OF

RADIORE Z MASSIVE SULPHIDE DEPOSIT

6.1· Introduction

Important exPérimental ,hemical data at hydrothermal conditions

have been gathered on basalt/water interaction in the last de cade or 50

Ce.g., Bischoff and Dickson, 1975; Seyfried and Bischoff, 1977; Mottl and

Holland, 1978). The dominant changes in the basaIt are in the concen­/'

trations of K, Mg, Ca, Na and S04' The magnitude of these changes are

a function of water-rock ratio (Seyfried et al., 1978), temperature and

IcTystallini ty. The presence of CO2 in the aqueous flmds has been shawn

by Iiyama (1961) to have a marked effect on the solubility of Si02 and

NaZO at hlgh tempe rature (400oC) and' CaO at low temperature (ZOOoC).

Mùr~ recent experiments by Bishoff et al. (1981) on the interactIon I)f . graywacke with chloride-rich brine and with seawater at 350°C shows that

" the degrec of metal mobilization is greater with the brine than with

seawater. \ These experirnents point out that cOmpositIon of the fluids

and the change in temperature have a strong influence on the type of

alteration and metal solubility.

The g~scovery of hydrothermal phunes in the Galapagos rift (Weiss

et al., 1977) and the extens ive exploration of these, submarine thermal

springs (Corliss et al., 1979) has shawn, in spite of the small size of

the thermal spring mounds relative to Imown massive sulphide deposits,

that there are striking sirnilarities with massive sulphide deposits, and

that they may be the consequence of exhalative hydrothermal activity

wherever it occur~.

...

)

---

, 1

, \

1 , i

1

- 85 -

1 At Galapagos -the sampling of hot springs has revealed that the

~omposition of the water can be explained by hydrothermtl reactions .

between seawater and basaIt (Edmond et al., 1979). One of the important

, conclusfons ..;frorn the chemical analyses of the springs is that there is , .

a linear correlation between the concentrations of sorne elements and

• ternperature, which is interpreted by Edmond et al. (1979) "as a series

of dilution lines generated by mixing of the hydrothermal fluids with

seawater". The behavior of the major elements can be summarized by a

uniform increase in concentration of K, Ca, Si, and Mn in the fluids

wi th increasmg temperature frorn 3 to nOc and convérsely by a depletion

of Mg. Motti and Holland (1978) have reported similar changes in

seawater/basalt experiment at temperatures at 200° and 400°C. For

exampIe, Mg is strongly partitioned into 501id phases ~ring high­

temperature 5eawater/basalt interactions; Na is also r~moved from the

fluid, but Ca, and ta a less extent K, become more concentrated.

In the forthcoming paragraphs it i5 proposed that the mineral-

ization and the alteration trends at Radiore formed from element

solubili ties.

6.2 Discussion: Hydrothermal Alteration

The major difficulty in endeavoring .to establish the ore fonning

chemical environment in these rocks is in establishing the changes that

took place from sedimentation through diagenesis and metamorphism. If

temperature, pressure and activities of the various components are not

maintained new mineraI assemblages will be generated. These conditions

are seldom preserved in ore deposits, hence substantial parts of the

assemblages seen today have formed under different physico-chemical

1 L

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,.

1 1-

~ ,

(

J ___ ~_~

- 86 - ,

enviromnents than the ore. This situat:i,on has also been encountered at

Radiore: petrographie study of the altered metavolcanic rocks suggests

that hydrothermal al teration was followed by a regional metamorphism to

the lower amphibolite facies which overprinted the volcanic and intrusive

rocks and the massive sulphlde ore (Chapter 3). ,

In discussing hydrothennal alteration 1t lS unportant first ta

examine the physico-cnemical parameters related ta the ore-forming

solution. In the Matagami area little has been done along this line:

° a temperature of 300 C for fluids discharged through the footwall at the'

Mattagarnl Lake mine has been deri ved from oxygen isotope data (quartz-

chlorite pairs) by Costa et al. (1980); and based on the efiect of

desilication of the rhyolite and from other geological evidence MacGeehan

(19~9) estimated that water/rock interaction in the geothermal system

below Garon Lake mine occurred at a pressure below 600 bars and a

temperature in the range up to 400-5000 C. No data 1S available on the

composition of the fluids responsible for the alteration, therefore an

assl.UlIption will be made, based on experimental data and fluid inclusion

analysis of similar deposits in proposing the model.

This model is based on the assumption that ore components were

derived fram extensive leaching of the Bla unit by heated seawater -

derived brines that formed a circulatmg geothermal system. A first

consideration requires the establishment of the vertical dimension of

the geotheTl11<}l system. MacGeehan and MacLean (1980b) have postulated

that in order to prevent heated circulating seawater from escaping

upwards an impenneable caprock (in this case Radiore rhyolite) overlaying \

the reservoir is needed. This condition has been stressed by Edmond et

• )

,

,

(

, .....

•

(

- 87 -

( -

al. (197.9) who stated that, in order to fonu sulphides in -t?e hot springs ,

at the 'Galapagos, ore-fonning solut ions must not come to contact ("titrate")

at depth with colder alkaline oxygenated seawater. A thickness of 100 •

metres of Bla is estimated from the stratigraphy. Flow of heated water

from the reservoir would be' restricted between the overlying Radiore

rhyolite and the underlying Norita rhyolite. This allows an estimate of

the lithostatic pressure of about 30 bars. The height of the seawater

column is unknown but from geological considerations 200 to 250 bars of

pressure could he added (HacGeehan and HacLean, 1980b, proposed a spreading

ocean ndge basaIt genesis for the volcanic rocks at MatagaITIl) .

Consequently a total pressure between 250 ta 300 bars 15 estimated l"

for the geothenual system. A moderate salinity is also to be expected.

In general, fluid inclusion analyses of massive sulphides yield an

average salinity of lM NaCl with a maximLun of 2. SM (Lambert and Sato,

1974). A temperature of 3000C estimated at the Mattagami Lake mine by

Costa et al. (1980), is a temperature of the fl~ids at the exit onto the

seafloor.

Turning now to the question of rock alteration, recent experiments

on water/rock interaction (Seyfried and Bishoff, 1977; Humphries and

Thompson, 1978) have shawn that different mineral assemblages are

produced by different water/rock ratios. Furthermore, Lydon (1980)

proposes that the highest concentration of metals in solution occurs at

low water/rock ratios and high pH in the fonnation of a chlorite-a1bite

assemblage, while the opposite occurs at high water/rock ratios and 1aw

pH with production of smectite. Fig. 6.1, in which mineraI stabilities

buffered to specifie pH values, serves to illustrate this point (page 90)

..

(

..

./

(

- 88 -

These considerations appear to fit weIl the explanation of the different

alteration assemblages present at Radiore and may also explain the

• mineralization. As the buffering' of pH is important in producing

different assemblages it IS appropriate to introduce the alteration

processes acting during metasomatic equllibria. Hemley and Jones (1964)

have proposed three main tyPes of reactions:

1) Simple cation exchange which do not invol ve H '*:

2) Pro~uction of hydrous phases which c~nsume H + and release other

cations.

3) Cation fixation reactions which produce H+ and release other

cations.

It is evident that the third reaction is the dominant one in

producing a lower pH and buffering alteration mineraI reactions. In

order ta consider the reactions it is important to recall some early

statements. Tt was suggested in Chapter 3 that at Radiore the chlorite-

o

~ albite-sericite assemblage was likely the dominant hydrothermal alteration

Cspilitization) and that subsequent potassium mctasomatism and \).

chloritization was superimpos~d onto tt. In fact the hydrothcrmally

altered mineraIs were prohably formed by a direct replacement and

, pseudomorphing of the primary mineralogy: albIte pseudomorphs plagioclase,

sericite pseudomorphs K-spar, actinolite pseudomorphs pyroxene and sphene (

pseudomorphs ilmenite or ulvospinel. Evidence of pyroxene-actinolite

transformation is reported by MacGeehan (1979) who describes pyroxene

as the original ferromagnesian mineraI in the basaIt. Chlorite and

biotite do not have a sÏmllar relation to the primary mineralogy, and

both of these mineraIs have been found in other alteration assemblages.

( "

- 89 -

In particular biotite is interpreted to have been mostly formed during

K-metasornatisrn.

During spilitization, in addition to reactions 1 and 2. rnagnesiwn

in seawater and rock form reactlons of the type 3 which produce ch10Ti te

(tf~ley et al., 1980; Bishoff et al., 1981):

2+ 2+ + 5 Mg ... anorthite .,.'8 ~20 T SiOZ = clinochlore ... Ca + 8 H

u

5 Mg2!. Z K-spar + 8 .HZO = clinoch1ore + 2 K\ 8 H\ 3 SiOZ

There is no c1ear texturaI evidence as to what reactants have produced

biotite during K-alteration but it may have been ch10rite formed during

spilitization. During chloritization the reverse reaction is observed

in thin section, and the follawing reaction is proposed:

Another point of importance is that with increasing temperature

the ionic dissociation of e1ectro1ytes decreases (Hemley et al., 1980)

wit~ the resu1t that the alteration processes are inhibited.at depth.

Silicification deserves a separate discussion. MacGeehan (1979)

whp studied the major elements and MacGeehan and MacLean (1980a) the

trace and rare earth gcochemistry of the rocks in the district concluded ,

that silicification has been a widespread a1teration in the area.

Examination of the textures shows that addition of silica has occurred

in open spaces, and the numerous inc'lusions (probably fluid inclusions)

in quartz grains suggest a secondary origin of quartz. The replacement

processllas not completely destroyed the original texture, for, as

....

(

1

i !'

1 ,

(

- 90 -

Hernley et al. (1980) pointed out, slow reactions and small pH gradients

do not favour the destruction of textures dunng silicification. The

same authors ernphasize the importance of H+ that needs ta be continually

produced durlng dissolution as sllica precipitates to maintain the

reaction and balance the pH.

AlI this confinns that alteratlOn has taken place in a slightty

alkaline seawater solution which has become progressively more acid.

The forgomg consideratlOns allow sorne generalizatlon about

alteration processes developed at Radiare and 'the path is shawn in

Fig. 6.1.

200

T'c

100

o 2 3 4 10

pH

Fig. 6.1 Temperature vs pH plot. Curve l and 2 are quenched pH measurements of seawater-basalt interaction experiments. Curve 3 calcu1ated for Na20-MgO-A1203-SiOZ-HZO-HCl system as~unung 1.0 m NaCl and Mg the same as for smectite-a1bite stability at the same temperature, after Lydon (1980). The s tab ili ty boundary for mica and K -spar shawn for K = 0.01 m is after Barnes (1979).

( \

- 91 -

1) Alkaline seawater interacts with basalts and as it i~filtrates

them type 2 reaction will be predominant so that a stable

greenschist facies assemblage (chlorite-albiteJ is ptoduced along

the pH-buffer curve which decreases in pH with mcreasing

temperature. Also, alteratlon will decrease as ionic dIssociation

becomes weaker with depth. In general if nothlng else occurs to

the solution Ce.g., a geothennal system is not established) the

process will cease.

The condition required ta convert the chlorite-albite assemhlage

(Fig. 6.1) to smectite-albite assemblage is an Increase in water

Irock ratio (Lydon, 1980). It may be that additlonai water-flux

developed as the reservoir is heated from below (sills and dykes

are a cammon feature) setting up a convective system. At lower

pH a mica and then a chlorite-contalning assemblage is produced.

The inverse solubility of Mg with increasing temperature is seen

as the major process during chloritic alteration. This reaction'

was illustrated earlier on. On the contrary K-metasomatism is

expected to be more effective in the alteration at lawer

temperature. A sequential order of reactions is therefore

proposed: K-fixation (biotite) and carbonate precipitation, "

followed by Mg-fixation as chlorite as the geothermal gradient '.

increases. In general this pattern is observed at Radiore:

more chloritized rocks at the base of the sequence and a

predominantly potassium rich zone! (metasediments) at top.

---~

(

(

(

/

- 92 -

6.3 Re1ationship Between Alteration and Ore Deposition

The maj or endeavQr in this Chapter is ta relate wal1rock a1teratio~

to the ore deposition. Unfortunately at Radiore this evidence is not

readily available because of lack of outcrop and because diamond drill-

cores do not show lateral relationsrips. The uneven distribution of the

samples have also precluded the reconstruction of the shape and extent

of the alteration zone, but as already described the wallrock alteration .,...

is in many ways similar to other deposits throughout the world.

Current knowledge of hydrothermal ore-forming fluids suggests

that chloride complexes are the major metal carriers in solution. One

of the problems with such complexes is that they are capable of metal

transport on1y in the presence ot' low su1phur concentration at low pH

(Skinner, 1979), and this is a severe constrain on the formation of

Archeah massive su1phides. OtheTh'ise su1phur would have ta be brought

ta the site of deposition and probably reduced, but reducing agents are

either slow or on1y effective at a very low tempe rature . Bisulphide

complexes are suitable as metal carriers and more stable at neutral to

alkaline pH (Fig. 6.2). Lydon (1980) has first propased that a1kaline

solutions derive the metals essential for the Zn-Cu base metal

association. Comiidering the alteration mineraI buffers fonned in the

mine rocks (Fig. 6.1), it seems appropriate ta postu1ate that a similar

path was responsible for the metal leaching and transport to the site

of ore deposition.

f t f , t , .. i 1

(

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- 93 -'

300 '\"

'fc, '1c,

... " 01'0

200

T "c .......... Cu> 1

1

pH

Fi~. 6.2 Concentration (log mg/kg) of metals ln 3.0 NaCl.solution in o equilibrium wlth Py-Cpy-Bn-Sp-Ga-Au-(Fa) assemblage to a max.

IO.Dm S content, after Lydon (1980).

Reconstruction and Proposed Model for Radiore 2

The field relationships, mineraI assemblages and textures are

consistent with a volcanogenic-exhalative environment of formation for

the Radiore deposit. The massive sulphide occurs at the top of strongly 1

altered volcanic rocks and is overlain by les5 altered ones; zoning and

mineraI banding ois developed in the ore; metasediments or tuffs faTm part

of the footwall; stockwork mineralization is absent; and weakly altered

dykes and sills intrude the altered rocks and the maSSlve sulphide

deposit. AlI these characteristics are generally consistent with the

majority of massive sulphide deposits found in the Canadian shield.

A reconstruction of the geothermal model is presented in Fig. 6. 3

and the forgoing 1S a summary of this interpretation.

, .'

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•

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1 ; f !

-\.,.. ,

( ,

Radiore Rhyolite

Metavolcanic 81a

[ Na + ] '-_trGlion in the flviel

( K +) Concenh'atlon in the rock

- 94 -

Heat Source

E:ZI &$U3 ~ ~

Spilitltalion

K· metalOlftClti ...

Chlonti1atian

r. 2+ + - 021 ~g·Na· CI·S 4 J

Seawater

Fig. 6.3 Schematic illustration of the geothermal~system developed below Radiore 2 deposit.

. ,

.. (

- 95 -,

1) The Radiore rhyolite was extruded above Bla metavolcanic (probably

a basaIt).

2) At intake points moderately alkalic seawater solutions interacted

as they moved slawIy downwards through Bla producing hydrolitic

alteration of the mafie mineraIs and calcic plagloçlase, and added

silica to the rock, not only by deposition III 0Ren spa ces (veinlets)

but also by replacem~nt (dissolution and redeposition) of silicate

mineraIs. At the same time congruent or near congruent exchange

of cOmponents took place between rock and fluids (MacGeehan, 1979).

A greenschist facies mineraI assemblage (spilitization) was produced

and heavy metals (Cu, Zn, Ni, Fe, Mn, etc.) were solubilized and

transported. It is evident fTom the thinness of the reservoir,

that heat was supplied at depth, probably by one of the numerous' ,

sills found there.

3) As the local geothermal gradient rose, new influxes of fluid changed

the water/rock ratio of the system ln which a greenschist facies

mineraI assemblage was being formed. At the same time the fluids

moved upwards. This caused K-fixation (potassium metasomatism)

and precipitation of carbonates at the low tempe rature end of the

, system, but as the fluids reached sorne max1J1lUlTl of ternperature

and pressure Mg-fixation (chloritization) prevailed.

4) At the discharged point 'Pe-Cu-Zn-Au-S were deposited. Ni, Co, V

and Mn may have formed more dispersed phases on the seafloor.

5) After depos i tion of the overlying volcanics and metasediments,

the lenticular shaped ore body was slightly deformed. A recon-

struction of the evolution of the orebody is depicted in Fig. 6.4.

" --~

(

..

1

f J

t

(

1 . ~

96 -

.\

Schema tic Evolution' of Radiore 2 Mine <,

Stage' ' -., "", .. ;s-.q ····::·:·:·:.:.::: .. L.:.JJQ!! ~ ........ !..: ... : ~

...... :.:::.: .... : ..... ::0;. .. ': ..... ; ••. ': .. ':' .. ':'.': .. ::.,. .' .. ~ ······ .. · .. ····RR······· ,

Stage Z

Stage 3

~~,{, :t""·~.·: i.;~J,~?·,. """"i::''''"(,,.: . :"", .'.'" ,. ".:... • • • • ~ ~ ';.' •• , " - ~:'X_~~'

•••••• ' ',' • ",, ", ,', • 1 ... " .... 0, .................. \ ••••••••• It~.' •••••••••••• '" ..... ~ .. ,' __ ', ••••• '" ft +0. l," ',' '..... ••••••• ....... ., : •• : • . ..... ," R·R .. ·· .. ··· .. ··· .. :· ...

Legend

~ Dyke " E::::J B1b

~a <I)Upper Ore Zone ~. .

b) Mètas6diments

c:::J Lower Ore Zone

f··:r'·:jl Radiore rhyolite (R R )

Fig. 6.4 A schematic reconstruction of Radiore .2 soon after ore deposi tion,.

11

,

' ....

..... ,

(

..

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- 97 -

'f!1e thickening and thinning of the orebody is interpreted to be

due to small irregularities in the original repository basin.

At the western end of the deposit a fauIt offset the contact ~

between the hanging-wall rock and the massive sulphide ore.

6) Sills and dykes were intruded at various stages through the

volcanic sequence and locally producing contact metamorphism.

7) Because of the poor exposure, little structural interpretation

has been carried out in the area. Consequently, time relation-

ships betyle,en the fonnation of the large anticlinal structure in

the district (Sharpe, 1964) and the bU1"ial metamorphism is not

clearly known, Following MacGeenan' s (1979) interpretation of

the Garon Lake deposi t a folding phase preceded regional metamor-

phism which marks the last event established at Radiore .

r

~~-;:;;-...... -~", ~,.:;;;~~--:-""-'-"'-----_._---"'.""\""",_.,,,;-------------_ ........ ~- ~--- ~_.

1

i

\ ~

i

(

0' ~w",,,,,,,,,~ ~""'P1"~"" ..... ,,~_ ~ 1\ .. "..,. .,.~001~'~ .... ,'""*'_ , ,~.~~o..r:. ... If • ~'1"",,\."

1

,- 98 -

CONfRIBlITION

Mapping and sarnpling of Radiore 2 mine has led to the re-

7nterpretation of the stratigraphy and shown that the massive

sulphide deposit is a volcanogenie acclUffillation of distal type.

Petrographie studies have ind1.cated that a progress ive

hydrothennal al teration is the main cause of the different mineral/

assemblages fotmd i~ the wall-rock. .. ,

The geochemistry of the wall-rock has confinned the tholeiitic

character of the extrus ive rocks associâted wi th the mas 5 ive sulphide

ore.

The geochemistry of the massive sulphide ore has doctunented

that groups of elements tend ta concentrate in the ore in the same

range of magnitude.

J

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1 l

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- - 99,"-

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._---------- f.

(

- 100 -

Bischoff, J.L.,'1969, Red sea geothermal brine deposits: their

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(

101

Cdnstantinou, G. and Govett, G.J.S., 1973, Geology, geochemistry and

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\'

\

( \ \ J

- 102

Goodwin, A.M., and Ridler, R.H., 1970, Abitibi orogenic belt: Geological

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( )

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(

, .

- 104 -

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Epithermal Deposits, Whitehorse Geoscience Forum.

MaeGeehan, P.J., 1978, The geochemistry of altered volcanic rocks at

Matagami, Quebec: A geotherma1 mode1 for massive sulfide

genesis: Cano Jour. Earth Sei., 15, p. 551-570.

, 1979, The petrology of volcanic rocks at Matagami, -------Quebec, and thelr relationshlp ta massive su1phide

minera1ization: Unpub1ished Ph.D. thesis, MeGil1 Univers~ty,

Montreal, Quebee.

______ and MacLean, W.H.,' 1980a, Tho1eiitic basaIt-rhyolite

magmatism and massive su1phide deposits at Matagami, Quebee:

Nature, 283, p. 153-157.

1980b, An Archean sub-seaf1oor

geotherma1 system, 'ea1c-a1ka1i' trends, and massive sulphide

genesis: Nature, 286, p. 767-771.

------------------------------- and Bonenfant, A., 1981, Exploration

signifieanee of the emplacement and genesis of massive

sulphides in the Main Zone at Norita Mine, Mat agami , Quebee:

C.r.M. Bulletin, p. 1-16.

Mae Le an , W.H. and MacGeehan, P.J., 1976, Garon Lake Mine, Mat agami ,

Quebee: Case history 76-1, MERl ~ineral Exploration Researeh

Institute).

J fI'" ,

(

- 105 -

MCDonald, J.A., 1967, Metamorphism and its effects on sulfide assemblages:

Mineralia Deposita, 2, p. 200-220.

Me1son, W., Thompson G., van Andel, T.H., 1968, Volcanism and me t amo rphi sm

in the Mid-Atlantic Ridge, 22 0N latitude: Jour. Geophys. Res.,

75, p. 5925-5941.

Mercer, W., 1976, Minor elements in meta1 deposit~ in~edimentary rocks­

A review of the recent literature: Chapter l,~. 2, "Handbook

of strata-bmmd and stratiform ore deposits". Ed. by K.H. Wolf.

Ntlyashiro, A., 1974, Volcanic rock series in is1and arcs and active

continental margins: Amer. Jour. Sei., 274, p. 321-355.

MOttIe, M.J. and Holland, H.D., 1978, Chemical exchilllge during hydro­

thermal a1teration of basaIt by seawater. I. Experimental

results for major and minor components of seawater: Geochim.

Cosmochim. Acta, 42, p. 1]03-1116.

Iiyama, J.T., 1961, Etude préliminaire de la solubilité du pasalte dans

l'eau â haute température: Bull. Soc. Franc. Minér. Cristo

LXXXIV, p. 128-130.

Irvine, T.N., and Baragar, W.R.A., 1971, A Guide to the Chemical

Classification of the Common Volcani~ Rocks: Cano Jour. Earth

Sei., 8, p. 523-548.

NRCC (National Research Council of Canada), Effects of Cadmium with

Canadian Environment: Publication No. NRCC 16743.

Ohmoto, H. and Rye, R.O., 1974, Hydrogen and oxygen isotopie compositions

of f1uid inclusions in the Kuroko deposits, Japan: Econ. Geol.,

69, p. 947-953.

/

c

1

1

( \

- 106 -

Pasitschniak, A., (in preparation), The sulfur content and sulfur

isotopie composition of Archean basa1tic rocks in Matagami,

Quebec, and their re1ationship to massive su1fides: M.Sc.

thesis, McGill UniversIty, Montreal, Quebec.,

Pearce, J.A. and Cann, J.R., 1973, Tectonic setting of basic volcanic

rocks determined using trace e1ement analyses: Earth Planet.

Sei. Lett., 19, p. 290-300.

Roberts, R.G., 1975, The geo1ogical setting of the Mattagami Lake Mïne,

Quebec: A volcanogenic massive su1fide deposit: Econ. Geol.,

p. 115-129.

and Reardon, E.J., 1978, Alteration and ore-forming

processes at Mattagami Lake Mine, Quebec: Cano Jour. Earth

Sei.; 15, p. 1-21.

Rockingham, C.J. and Hutchison, R.W., 1980, Metamorphic textures in

Arche an copper-zinc massive sulphide deposits: C.r.M,

Bulletin, p. 10~-112.

Seyfried, W.E. and Bischoff, J.L., 1977, Hydrothermal transport of

heavy metals by seawater: Earth Planet. Sei. Lett., V. 34,

p. 71-77.

Mott1, M.J., Bischoff, J .) .. " 1978, Seawater/basalt ratio , .

effects on the' chemistry and.minera1ogy of spilites from

ocean fIoor: Nature, 275, p. 211-213,

" Sharpe, J.l., 1964, Precarnbrian geology and sulphide deposits of the

Matagami Area, Quebec: Unpublished Ph.D. thesis, McGill'

University, Montreal, Quebec.

('

(

- 107 -

Sharpe, J.r., 1968, Geo1ogy and sulphide deposits of the Matagami Area,

Abitibi-East County: Quebec Department of Natura1 Resources,

Geo1ogica1 Report 137, p. 122.

Shaw, D.M., 1964, Interprétation géochimique des éléments en traces

dans les roches cristallines: Masson and Cie Ed., Paris.

Shido, F., Miy~shire, A. and Ewing, M., 1974, Compositional variation

in pillow lavas from the Mid-Atlantic Ridge: Marine Geo1ogy

.~ 16, p. 177-190.

Skinner, J.B., 1979, The many origins of hydrothermal mineraI deposits:

fram "Geochemistry of HydrotheTITlal Ore Deposi ts ", Edited by

H.L. Bames, Second Edition.

Spooner, E.T.C., 1977, Vo1canic processes in ore genesis: Inst. Mining

and Metal1urgy, London, p. 58-71.

Stanton, R.L., 1964, Mineral interfaces in stratiform ores: Inst.

Mining Metallurgy (London) Trans., 74, ho. 696, pt. 2,

p. 45-79.

Steger, H.F., 1980, Certified Reference Materials, CANMET Report 80-6E:

Energy, Mines and Resources Canada, Ottawa.

Taylor, S.R., 1965, Geochemical application of spark source mass

spectrometry. Table 83-E-l, fram: Bismuth '~andbook of

Geochemistry", Springer-Ver1ag, Ed. by K.H. Wedepohl.-

Vincent, E.A. and Bilefie1d, L.T., 1960, Cadmium in rocks and mineraIs

from the Skaergaard intrusion, East Green1and. Table 48-E-3

from: Cadmium '~andbook of Geochemistry", Springer-Ver1ag,

Ed. by K.H. Wedepohl.

'" ,

(

c

•

Vi~ogr8:dov,. A.P.-,~1962, AVE!rage contents of chemical elements in the

principle types of igneous rocks of the earth 1 s crust

Geochemistry, Table 74-E-1, from: Tungsten '~andbook of

Geochemlstry", Springer-Ver1ag, Ed. by K .H. Wedepohl.

Vokes, F.M., 1969, A reVlew of the metamorphism of sulphide deposits:

Earth Sei., S, p. 99-143.

Weiss, R.F., Londsale, P., Lupton, J.E., Bainbridge, A.E., and Craig,

H., 1977, Hydrothermal plumes in the Galapagos Rift: Nature,

267, ~. 600-603.

'l/illiams-Jones, A.E., (in press), Patapedia; an Appalachian cale-silicate

hosted copper prospect of porphyry affinity: Cano Jour. Earth

Sci.

Winc~ester, J.A. and floyd, P.A., 1976, Geochemical magma type

discrimination: Application ta altered and metamorphosed

basic igneous rocks: Earth Planet. Sei. Lett. 28, p. 459-469.

, Winkler, H. G. F ., 1979, Petrogenes is of Metamorphic Rocks: Springer-

Verlag, New York Inc., Fifth Edition.

Woakes, M., 1961, nTi1I hole logs: InternaI Report of Radiore Uranium

Mine Ltd., Matagami. Courtesy of Noranda ~ne3 Ltd.

'.

\

l

t

/1

!

•

t'

,

- 109 -

APPENDIX l

SAMPLE PREPARATION AND ANALYTlCAL PROCEDURES

l - l Samp ling

During detailed tmdergrotmd geologieal mapping of Level No. 1,

sampling of the orebody an1 the enclosing rocks was carried out. Sorne

of the diamond drill-holes from exploration drilllng were re-logged and .

sampled. Outcrops exposed by mining activity were also sampled. From

the nruek-pile outside Radiore Mine two samples of massive ore were '-

collected and an additional five samples from the same pile were randomly

picked up by Mr. A. Bonenfant, the mine geologist, at a later stage.

Approximately l kg of hand sample was collected at each sample loeali ty

and 0.5 kg from diamond ,drill-core. Each sample was labelled with a

number preceded by RAO, which identifies Radiare locality. Samples from

diamond drill-core were retrieved using an additional labelling: the

original drill-hale mnnber and depth (in feet) from which the sample was

collected. AlI the samples' locality is reported in the Appe~dix V.

l - 2 Sample Preparation

(1) General

Sample selected for thin and po li shed section was eut with a diamond

saw to provide a thin section slab and clearly altered surface was chipped

off to remove weathered rind. The residual material was crushed in a jaw

crusher and ground in a Bieo rotary disc grinder using '"ceramic grinding

plates. A homogenized portion was subsequently groundoto -200 mesh in a

puck grinder. The remainder of the ground material, the rock and the

drill-core samples, are stored at McGill University.

(

•

,

j i

, 1

(

- 110 -

#, !

(2) Fused Pellets for XRF Analysis

One gram of sample powder was mixed with two grams <of lithiwn

tetraborate and transferred first ta an agate mortar, ground and

homogenized under acetone, and after, ta a graphite erucible and fused

in a rnuffle fumace for 30 mmutes at 1070 0 C. The glass bead 50

~. fonned was then crushed in a steel mortar and pulverized. The powder

was wetted with mowoil 2% at a pressure of 20 - 2S tons/cm2 for one

minute.

(3) Powder Pellets for XRF Analysis

Approximately two grams of sample powder was wetted with mowoil

2%, 'then backed by borie add and pelletized in a hydraulic press at a

pressure of 20 - 25 tons/em2 for one minute.

I - 3 LOS5 on Ignition (LOI)

(1) LOI Analysis

A silica glass capsule was preheated for ten minutes to drive

off a11 volatiles, eooled in a dessicator for five minutes and weighed

ta the nearest 0.1 mg. One gram of sarnple P?wder was then transferred

into the capsule, weighed again and heated in a rnuffle fumace for 30

minutes at 1075 0C. The capsule was then removed from the aven, cooled,

set' in a dessieator for ten minutes and ü!lally welghed again. The

o twtal loss of volatiles (LOI) of aIl the samples analyzed for major and

trace elements was determined. Duplicates were run to check the

precision of the method and are reported in brackets in Table I-a.

•

l -. • !r .. J<~ "':",~t'll~~"'I ... r--i'" ,...,.,....r~""riI"I-..;.,.r""' .... '-""I"r..,."'J. .... ~_ .. : ~ ....... ,-.......... ~ .. ~. _ l''' __ ~'_''_ ~_ • ..,. __

! \ 1

( }

..

(

( . - 112 -

, (a) LOI Calculation

j

% LOr = wt. of volatiles lost during ignition x 100 . ini t ial wt •. of powder

1 - 4 X-Ray Fluorescence Analysis (Major Elements)

AlI the samples were analyzed for nine elements (SiOZ' Al-z03'

Fep3*' MgO, CaO, NaZO, K20, Ti02, PZOS) using a Philips PW 1220 X-ray

fluorescence spectrometer and chromium tube. AlI data are standardized

against U.S.G.S. l standdrd BCR-l, corrected for rnass absorption and

nonnalized ta 100% (Appendix - III-a) using a mlcroprocessor mstalled

at McGill University. Nonnative CIPW reported in. various tables were

camputed using a Fortran IV program NORCOMP, the calculation method of

C. Kelsey.

Ca) Accuracy of the XRF Analysis

The precision of the XRF determination was perlodically tested

by anaIyzing BR Inte,rnational Standard over a total of eighteen nms.'

The mean and standar:ri deviation of eleven replicated analyses of BR, ,

corrected for mass dbsorption but not nonnalized is reported in Table 1

1-4a and compared to "usabIe" values for this standard compiled by

Abbey (1977).

* FeZ03 detennined as total iron

1 United States Geological SUIvey

1

, *" ."

,1 '1 ,

<' ,1

( î ,~ r;t\l

.... 1 '

(

- 113 -

/ (b) Precision of Sample Preparation

The reproducibility of sample and fused pellet preparation was

tested only on one sample. Two separate splits of this sample were

fused and then pellets made and analysed. The resul ts are reported in

Table 1-4b. A second check was made by addmg the detennmation of the

volatiles (LOI) ta the XRF data before nonnalization. If the summation

of derived values was ranging outside 98-101 total wt. ~ the specifie

sample w~s discarded and made agam. /

l - 5 X-Ray Fluorescence Analvsis (Hinor and Trace Elements) ,

The Cu, Zn, Ni, Mn, Cr, Rb, Sr, Y, Zr, Nb and S contents of aIl

the rock samples were determined using X-ray fluorescence techniques.

In four sarnples, Zn, Cu, Pb, Sn, As, Bi, Mo, Cd, W, Co, Cr, Ag, AU,-Ni,

and V were determined by atamic absorption techniques. The latter

analyses were made at X-Ray Assay Laboratanes Ltd., Toronto and by

Barringer Magenta Ltd., Toronto, in conjunction with analysis of the

massive ore (Appendix III-b).

Ca) Cu, Zn, Ni, Mn, Cr Detennination

These elements were measured by XRF on pressed powder pellets

using a molybdenum tube and BR as standard (Appendix III-b). The trace

element contents of these samples were calculated using the following

fonnula:

( ,

"-

Net cps X m. u.c. XxppmS=ppmx x Net cps S m.u.c. s'

, X = sample ppm = value in part per million

S = standard cps = counts per second

m. u. c. = mass absorption ~oefficient

. ..... , ,U'~,,-~~~_~~~\ .. ~~~-:-~~~_ ..,.~ •. .•

;

, , ~

(

- 114 -

Table: 1-5a

Trace Element (Zn, Cu, Ni, Mn, Cr) Ana1ysis of

HM1 and r~2 International Standards Against

BR3 as Reference (values in ppm)

Zn Cu Ni Mn

BM1 (Abbey, 1980) lOS 45 57 0.14'%

SM (measured) 132 45 69 1645

130 43 67 1685

GAZ (Abbey, 1980) (-

80 16 7 0.09%

GA (measured) 89 24 12 857

/

"r. .'~

1 Zentrales Geo1ogisches Institut (East Germany)

Cr

125

166

180

12

4

2 Centre de Recherches Petrographiques et Géochimiques (France)

3 Centre de Recherches Pétrographiques et Géochimiques (France)

1 -

(

f

f , i

(

- 115 -

The precision of the analysis was checked against BM and GA

International Standards (Table I-5a) and values are within range of

instrumental errors. The mean and standard devlation of seven duplicate

samples were also computed and the results are reported in Table I-Sb.

Cb) Rb, Sr, Y, Zr, Nb DeterminatlOn -

These elements were analyzed by XRF on pressed powder pellets

using a tungsten tube and BCR-I as standard (Appendix rrI-b). Calcu-

lations were computed using the same fonnula as for Cu, Zn, etc. outlined ,

above. The precision of the analys1s was checked against BR and BM

International Standards and they aIl fall within the range of instrumental

errors (Table I-Sc).

Cc) Sulphur Determination

Sulphur was determined using XRF calibration curves set up by

Pasitschniak (1981). This curve was established by plotting the percent

sulphur in a series of standard samples against .',the ratio of the X-ray

intensities (cps) of sulphur ln a momtor standard. It is asstmled that

JOOst of the sulphur 1S present in pynte ln both standard and unknown, hence

mass absorption corrections were not made. The equation corresponding to

this curve is: ppm S (unknown) = 5300 (cps unknown/cps standard)-50

Knowing the net cps of both the standard and the unknown, It is

possible to calculate the amount of sulphur ln the samples (Appendix III-b).

The accuracy of the sulphur determlnations was checked using the LECO

analytical method and faund ta be within ±4.4% of the sulphur concentration;

the precision of the XRF analysis is within 3.3';, of the sulphur concen-

tration (Pasitschniak, personal communication).

, - -)

'\

(

- 116 -

-Table:' 1- 4a

Mean and Standard Deviation of the C.R.P.G. 1 Standard BR (BasaIt) ~

No. of runs SiOz A120

3 FeZ03* MgO CaO NaZO KZO TiO Z

11 X 40.63 10.93 13.06 1Z.49 13.68 3.10 1. 37 Z.67

(anhydrous) S 0.24 0.17 0.04 0.15 0.40 0.11 0.01 0.02

Abbey (1977)

"Usab1e va1ue"38.39 10.25 11. 61 2 13.35 13.87 3.07 1. 41 2.61 (hydrous)

Table: 1-4b

ReprOducibi1ity of Samp1e Preparation

Sample

RAD 51

RAD 51

55.74 1Z.12 17.18 1.77 3.26 3.69 0.63 1.63 ,

55.79 12.95 17.33 1. 79 l' 23 4. 40 O. 66 1.. 63

1 Centre de Recherches Pétrographiques et Geochimiques (France)

FeO = 6.60

* Expressed as total iron

PZOS

0.83

0.27

1. 05

0.32

0.33

-{ <.. ., .;

1

/

(

1

\ \

- 117 -

Table: 1-5b

Duplicate XRF Ana1lses of the Zn, Cu, Ni,

Mn and Cr Content of Igneous Rocks

Sarnple Zn Cu Ni Mn

RAD 44 Values inpprn 89 20 15 1905

91 16 16 1954

RAD 50 104 27 35 2249

105 24 32 2264

RAD 51 63 38 8 906

68 36 12 953

RAD 52 66 24 14 1309

63 21 17 1383

RAD 54 117 24 43 )1567 114 19 30 1439

RAD 56 69 25 10 1443

~

~----~ 71 18 8 1284

RAD 60 7S 84 22 1111

69 93 2S 1123

N .D. = not detected

• ,~.p.<~ ,

Cr .

207

321

'. 165

\'

157

N.D.

N.D.

32

31

13

22

11

16

18

23

~,

!

(

- 118 -

Table: 1-5c

Trace Element (Rb, Sr, Y, Zr, Nb) Analysis of

Btt and BR2 InternatlOnal Standards Against

BCR-1 3 as Reference (values in pprn)

Rb Sr Y Zr Nb

BMl 12 230 26?4 105 (Abbey 1 1980)

BM 7 233 34 105 5

measured 6 233 30 108 7

BR2 47 1320 30 250 100?4 (Abbey 1 19802

BR 46 1389 33 296 87

measured

1 Zentrales Geo1ogisches Institut (East Germany)

2 Centre de Recherches Pétrographiques et Gécclrimiques (France)

3 United States,Geological Survey

4 Original analyses reported wi th a question mark

~

(~

(

- 119 -

l - 6 External Trace Element Analysis

X-Ray Assay Laboratory Ltd., Don Mills, Ontario, carried out

trace element determmations for 13 elements (As, Bi, Cd, Co, Cu, Cr, 1

Au, Pb, Mo, Ag, Sn, W, Zn) and Barringer Magenta Ltd., Rexdale, Ontario,

the determinat,lOn of three elements (Mn, Ni, V) on twenty massive ore \

sarnples collected at Radiore 2. An aliquot of approximately 50 g was

sent ta each laboratory for analytical detenninatlOn. The resul ts are

reparted in Table 5.1 (Chapter 5). The analytical methods used for

different groups of elements and the relative detectian limit are

reported in Table I-6a.

Three replicafe samples of the same sample powder (RAD 37) were

submitted with two dlfferent standard (KC-l and MP-l) abtained fram the

Canada Centre for Mineral and Energy Technolagy (CANMET) ta check

precision and accuracy. A similar procedure was used for samples

analysed by Barringer Magenta Ltd.

The results of the replicate analyses are, shawn in Tables l-6b

and the analysls on the standards are shawn ln Table 1-6c. The lead

determination ln KC-l is distinctly different from that given ~~ANMET,

suggesting an error in the analysis.

.L

t t f 'v ~

f r ~ f

~ , i

- 120 -

r

Table: 1-6a

Techniques and Detection Limit of 16 Elements in the Massive Ore

Element Analytical f\fethod

ARSENIC (As) N.A,

BISMUIH (Bi) F.A.A.

CAll-1IUM (Cd) A.A.

COBALT (Co) A.A.

COPPER (Cu) A.A.

CHROMIUM (Cr) X.R.F.

C'JÛLD (Au) F .A.-N .A.

LEAD (Pb) A.A.

MANGt\NESE (Mn) * A.A.

~LYBDENUM (Mo) A.A.

NICKEL (Ni)* A.A.

SILVER (Ag) A.A.

TIN (Sn) E.M.S.

TIJNGSfEN (W) N.A.

VANADIUM (V) * A.A.

ZINC (Zn) A.A.

Digestion:

Ni-V-Mn = Hydrofluoric/Percloric/nitric Ag :: Nitric Other elements = Nitric/Hydrochloric

Ana1ytical Methods:

= Atomic Absorption = Neutron Activation

Detection Liroit

1. 0 ppm

0.1 ppm

0.2 ppm

1. 0 ppm

0.5 ppm

20.0 ppm

1. 0 ppb

2.0 ppm

1. 0 ppm

2.0 ppm \

5.0 ppm

1.0 ppm

3.0 ppm

1. 0 ppm

20.0 ppm

0.5 ppm

= Emission Spectroscopy,(D-C are excitation)

/ 1

= Flameless Atomic Absorption (Hydride generation method)

A.A. N.A. E.M.S. F.A.A. F.A. X.R.F.

:: Fire Assay (preconcentration followed by neutron activation) = X-Ray Fluorescence

The asterisk(*) indicates analysis carried out by Barringer Magenta (/ Laboratory of Toronto, otherwise is intended by X-RAY Laboratory of Toronto. )

""'- /'"

I~·"-

! ;

l', l ,

, , ~, ~ li

f f t

f "

r

~ E, !;~

1. t !'

':

r-

~. ~

"

Table: 1-6b

~_ -=:.C-=:.CJIlfE;,;..~ ... =-.;:·;;;;;s ... o.,;;,~~o_f_th_e_T_r_a_c_e_E_l-:.e_m_en.:...-t_C_o_n_t:...e_n_t_i_n_p~pn1--_1...,;· n_Th~r_e..:.e_A~l;::.iqu~o;;..t:.;s~D..:.r..:.a:...wn~;::.fr,;:..om~ ~ ,

,/ ,/ the Same Sample Powder~etermined br X-RAY and Barringer Magenta Ltd. (*)

"

1 Au1 1

SAMPLE As Bi 'Cd Co Cu Cr Pb ~hl * Mo Ni * Ag Sn W V* Zn:

,

RAD 37 62 8.0 <1 520 2240 <20 460 28 80 <2 <5 13 5 <1 < 20 36

,

66 8.0 <1 520 2130' <20 400 32 80 <2 <s 16 8 <1 < 20 32

65 7.7 <1 530 2220 <20 36n 28 70 <2 <5 16 8 <1 20 38 - -- - .. - ---_ .. _-- ------

1 . b Values ln pp

~ /'

.. . """"~

.,-...,

'--

SAMPLE As Bi

MP-l 9400 230

"lJsahle" 0.77 0.024 -~~~-

KC-l 310 1.4

"Usable" - -_ . __ ._-_._._~- L- ____

1 Values in ppb

2 Values in ppm

~" t~-

.~-~ ~-;..~~~'-....l .... -~ .. ~

/'"

~ /'

Table: 1-6c

Comparison of the Trace Element Content in Ppm of MP-l and KC-l CANMET3

Standards Determined by X-RAY and Barringer Magenta Ltd. (*), Values in % i

Cd Co Cu Cr Au1 Pb Mn* Mo Ni* Ag Sn

450 - 21400 - 42 18000 560* 140 - <5* >20 256000

0.07 - 2.09 - - 1. 88 0.05 0.014 - 57.92 2.43 . '------ ----~- -------- ---- - ~ . ' .. --

-770 26 1070 <20 64 20800 220* 20 15* >20 6000

- - 0.112 - - 6.87 - - - - 0.112 0.67 - -- ~ ----

3 CANMET: Canada Centre for Mineral & Energy Resources ~ Trace element content suggested as "usabletf values by Abbey (1977)

~

t

W

230

0.02

,...., , ,

V*

~20*

-----------------

12 <20* '

- -

Zn

169000

15.90 _.-

1

2250001

20.07

( ,

."

l'

(

- 123 -

APPENDIX II

MEASURED BÛLK,OENSI1Y FOR TIrE EXTRUSIVE ROCKS

From sections of diamond drill-core, samples ranging fram 200

400 g in welght were used to determine the bulk composition of the

extrusive rocks. Cylmder shaped samples were cut on a diamond saw and

the precise volume was calculated using a venier caliper. Each speciman

was then precisely weighed and consequently the bulk density determined.

AIl the data are reported in Table II-a with the approximate estimate

ef pyrite present in the samp1e.

1

f ,

, . î

,Jl t

~, ~~ -,- ~ .. >'.:,' \_{.!,'1~'1-::,. ~~~"'I<~""",~~r"f_"~ J'o, ~ ..... _ , . " - .......... -- -~ ....... _~ .. , ... ...,-~ ..,.- .. -"' .. _----"j ~~, .,'"~ .... t·· ~'

1_

t

\. ~

- - 124 -

(, Table: II-a

Bulk Densi ty of the Different Rock TyPes-

Sample No. Rock Type !JI Unit

UR l2-l76m Qz-eye Rhyolite BCR

UR 9-76rn Ves icular- Rhyolite 8 RR

EE l6-95rn Vesicular Rhyolite 20 RR

EE l6-86rn Vesicular Rhyolite 12 RR

UR l2-296rn Brecciated Rhyolite l R~

UR l2-258m Brecciated Rhyolite l RR

UR 3-4rn K-rnetasornatized Rhyolite 9 RR

UR l2-31lrn Metasediment 2 RR

UR l2-47Orn ChloritlZed Rhyolite ~- RR

UR l2-40Srn Chloritized Rhyolite R~

EE 8-44rn Chloritized Rhyolite 4 RR

UR l2-312m Chloritized Rhyolite 1 RR

EE 8-46rn Chloritized Rhyolite RR

1 EE 7-6Orn Metavolcanic Blb

1

EE l7-82rn Metavolcanic Bla

UR l2-49Srn Metavolcanic Bla \ ,

UR l2-55Orn Metavolcanic Bla

J 0

not observed

(

1 'A'

r

Density

2.7

2.7

2.7

2.6

2.6

2.6

2.8

2.9 r-

2.7

2.7

2.7

2.8

2.8

2.8 ,

2.8

2.8

2,8

~,~ .... --<'" '.

.1-

rf-

1

·f (

1

1 j 1

1

1 ,1

1

1

!

le

",

1

...

•

,L

, - 125 ,

APPEND IX II l (./ )/

MAJOR AND TRACE ELEMENT Ca.1POSITION OF TIΠVOLCANrf ROCKS

The major elernent composition of individual samples are tabulated

in order of increasing SiOZ content. For each sarnple three datalmes

are reported: the first line indicates the un-norrna1ized analysis

corrected for mass absorptlOn; the second line shows the values nonnalized _

1 to 100%; the third Une aIl the analyses are represented with Fe203

ca1culated as TIOZ + 1. S'ô and residual iron ca1culated as FeO, after

I~ine and Baragar (1971), then nonnahzed aga in to 100i. AlI sample

locations are Identified in Appendix V with relative reference to the

map in which the exact locality of sarnpling was W1dertaken.

Breakdown List of Sarnples frorn the IndiVldual Rock Unit

Extrusive Rocks:

, Intrusive Rocks:

Rock Unit No Analyses

Bell Channel Rhyolite (BeR) 5

6 Metavolcanic

Radiore Rhyolite

Metavolcanic

,

Gabbro-Pyroxeni te

Quartz-Diori te

Granodiorite

Diabase

Gabbro-Diori te

(Blb)

(RR),

(Bla)

Total

..

.,

7

6

1

3

1

2

5

37

-' .;,

" J

~ 8

-~

1--,

'\

APPENDI~. MAJOR ELEMENT GEOCHEMISTRY

f' EXTRUSIVE ROCKS

STANDARD = BCR METAVOLCANIC (B1.a) 0.0 = NOT DETECTED Fe 0 CALCULATED AS TiO + 1.5% . STANDARD = BCR-I BLANK - NO~ DETERHlNED FOR 2 3 2 DILUTION FACTOR s 66.667 ."-

.' SAMPLE S102 A120 3 fe 20 3 FeO MgO CaO Na

20 K

20 1'1°2 PZOs LOI TOTALS

48.66 13.78 16.85 11.43 0.50 0.77 0.34 1. 38 0.03 5.98 99.72-

RAD 44 51. 91 14.70 17.97 12.19 0.54 0.82 0.36 1.47 0.03 100.00 52:71 14.93 3.02 13.7~ 12.38 0.55 o 83 0.37 1.49 0.03 100.00

51.45 13.73 17.52 11.10 0.41 0.23 0.05 1.48 0.16 6.23 102.36 RAD 79 53.52 14.29 18.22 11.54 0.43 0.24 0.05 1.54 0.16 100.00

54.35 14.51 3.09 13.87 11. 72 0.44 0.24 0.05 1.56 0.16 100.00

60.04 12.55 12.43 6.12 1. 93 1. 74 1. 06 1.19 0.10 3.30 100.46 • RAD 60 61.80 12.92 12.79 6.30 1. 98 1. 79 1.09 1.23 0.10 100.00

62.43 13.05 • 2.76 9.14 6.36 2. 00 1. 81 1.10 1.24 0.10 100.00

60.71 10.02 12.96 6.28 0.70 2.33 3.]4 '1.29 0.22 1.69 99.94 RAD 80 61. 79 10,19 13.19 6.39 0.72 2.37 3.81 1. 32 0.23 100.00

f" 62.43 10.30 2.85 9.43 .6.46 0.73 2.39 3.85 1.33 0.23 100.00

59.51 12.63 12.69 7.24 0.35 0.81 0.45 • 1.19 0.13 4.47 99.46 RAD 52 62.64 13.29 13.36 7.62 0.37 . 0.85 0.47 1.25 0.14 100.00

63.32 13 43 2.78 9.65 7.70 0.37 0.86 0.48 1.26 0.14 100.00 "J

65.89 10.33 11.99 5.42 0.36 1.47 0.46 1.24 0.02 3.85 101.03 RAD 45 67.80 10.63 12.34 5.58 0.37 1. 52 0.47 1.27 0.02 100.00

68.46 10.73 2.80 8.69 5'.63 0.37 1.53 0.47 1.28 0.02 100.00

RADIORE RHYOLITE (RR) * ~etasediments or TuEEs

24.90 18.81 33.60 10.91 1. 36 0.00 2.87 1.04 0.10 5.55 99.07 RAD 55 '" 26.62 20.11 35.92 11.66 1.46 0.00 3.06 1.11 0.1l 100.00

27.52 20.79 2.70 31.00 12.06 1.51 0.00 3.16 1.15 0.11 100.00

....

" 4

.. _ ............... ~ .... ~.l ..... ':,.

~ .... ~ ... ~ :;:f~ - ~".-~',!;<~ ;...

_...-"'~~''''''-..L

l, 1"""'" -

i "

.,

1,

EXTRUSIVE ROCKS (cont'd.)

STANDARD = BCR RADIORE RHYOLITE (RR)

'\ SAMPLE Si02 A12O) Fe

Z0

3

l' 39.60 17.86 13,28 RAD 54* 42.19 19.03 14.15

l, 42.63 19.23 3.83

1 \ 41.17 20.69 Il. 74

RAD 66* 43.18 21. 70 12.31 43.55 21. 88 3.98

47.81 12.77 15.15 RAD 16* 50.74 13.55 16.08

51. 40 13,72 3.10

69.49 10.46 5.34 RAD 62 72.89 10.97 5.60

73.14 11.00 2.25

73.61 8.26 8.31 RAD 63 76.80 8.62 8.67

77.33 8 . .69 1. 76

'1 75.57 6.19 8.60

RAD 53 79.14 6,49 9,00 ~9.12 6.53 1. 88

" METAVOLCANIC CBlb)

52.65 13.58 10.19 RAD 100 54.56 14.07 10.56

53.00 14.19 2.41

53.45 13, 00 14.96 RAD 30 54.29 13.20 15.20

54.93 13.35 3.70

... _''''-f.... ... " ~~~~' ... -.,

'\ 1

-JI

0.0 - NOT DETECTED

'-.

BLANK z NOT DETERMINED FOR

FeO MgO _ CaO

16.67 0.63 17.76 0.67

9.42 17.94 0.68

11.92 1 01 12.50 1. 06

7.58 12.60 1. 07

10.61 0.49 11.25 0.52

11. 87 11.40 0.53

6.n8 0.34 6.37 0.36

3.03 6: 38 0.39

2.69 0.,53 2.81 0.55

6.27 2.B3 0.55

4.09 0.17 4.29 0.18

6.47 4.32 0.18 c

y ---.--

; '.

'-. 11.32 4.86 . Il. 73 5.04 7.41 11.83 5.08

6.83 2.9~ 6.94 2.98

10.51 7.02 3.ûl

~ \::>

"

".1> -"-v-

Fe2

03

CALCULATED AS TiOz + J.5% STANDARD = BCR-l PILUTION FACTOR ~ 66.667'

Na20 K

20 Ti0

2 P205 LOI TOTALS

O.OZ 3.48 2.15 0.18 6.58 100.43 0.02 J.7l 2.29 0.19 100.00 0.02 3.75 2.31 0.19 100.00

• j

1. 98 4.46 2.33 0.04 5.60 100.94 l

2.08 4.68 2.45 0.05 100.00 2.10 4,72 2.47 0.05 100.00

0.37 5.48 1.47 ~4.38 98.43 0.40 5.82 1.56 0.09 - 100.00 0.4.1 5.90 1.58 0.09 100.00

0.42 2.50 0.71 0.00 3.22 98.55 0.44 2.62 0.74 0.00 100.00 0.44 2.63 0.74 0.00 100.00

1. 45 0.72 0.25 0.04 3.99 99.84 1. 51 0.75 0.26 0.04 100.00 1.52 o 75 0.26 0.04 100.00

0.20 0.31 0.36 0.00 3.40 98.89 0.21 0.32 0.37 0.00 100.00 0.21 0.32 0.37 0.00 100.00

2.38 0.64 0.85 0.03 3.59 100.09 2.46 0.66 0.89 0.03 100.00 2.48 0.~7 0.90 (J.03 100.00

2.20 2.55 2.12 0.41 2.91 101. 37

'\ 2.23 2.59 2.16 ,0.41 100.00 2.26 2.62 2.19 0.41 100.00

....... ""~......... ~ ~ ~ .... :~

,'-"" 1 _.- ~

~

~

"'"

• EXTRUSlVE ROCKS (cont'd.)

STANDARD - BCR METAVOLCANIC (B1b) 0.0 = NOT DETECTED FeZ03 CALCULATED AS TiOz + 1. 5% STANDARD = RCR-1

BLANK • NOT DETERMINED FOR DILUTION FACTOR = 66.667

SAMPLE 510Z A1z03 F.e20

3 FeO MgO CaO Na20 KZO TiOZ P205 LOI TOTALS

, {-57.13 12.43 15.60 3.17 4.18 3.76 0.80 1. 59 0.19 0.87 99.73 i

RAD 43 57.79 lZ.57 15.78 3.Z0 4.Z3 3.81 0.81 1. 61 0.20 100.00 . -!

58.53 12.74 3.15 11.55 3.24 4.28 3.86 0.B2 1. 63 0.20 100.00 l 4

61. 64 12.39 13.84 3.29 4.36 2.09 0.51 1. 46 0.21 1. 52 101.5Z RAD 56 61. 78 12.41 13.87 3.29 4.37 2.09 0.51 1.46 0.21 100.00

62.47 12.55 2.98 9.93 3.33 4.42 2.11 0.52 1.48 0.21 100.00

62.46 12.24 13.15 3.00 3.38 2.44 O.Bl 1.27 0.17 1. 56 100.47 RAD 58 63.15 12.37 13.29 3.03 3.42 2.47 0.82 1. 29 0.17 100.00

63.81 12.50 2.82 9.55 3.06 3.46 2.50 0.83 1.30 0.17 100.00

63.51 11.94 12.68 2.77 3.49 3.63 0.30 1. 07 0.30 0.82 100.41 RAD 42 63.77 11.99 12.73 2.7B 3.51 3.65 0.30 1. 07 0.30 100.00

64.40 12.10 2.58 9.22 2.80 3.54 3.68 0.30 1. 08 0.30 100.00

68.03 11.86 12.27 1. 89 1.82 2.90 1.19 0.85 0.12 1.04 100.90 RAD 64 67.41 n.75 12.15 1. 88 1. 80 2.87 1.18 0.84 0.12 100.00

68.08 11.86 2.36 8.92 1. 90 1.82 2.90 1.19 0.85 0.12 100.00

66.50 11.40 9.76 3.45 1. 68 2.16 1.80 0.82 0.09 2.36 100.03 RAD 59 66.08 n.68 10.00 3.53 - 1'.72 2.21 1.84 0.84 0.09 100.00

68.62 11. 77 2.36 6.94 3.56 l.73 2.23 1.85 0.85 0.09 100.00

66.98 11. 53 8.32 2.55 2.12 3.68 1. 74 0.83 0.16 0.64 98.45 RAD 78 68.39 11. 79 8.50 2.60 2.17 3.76 1. 78 0.84 0.16 100.00

68.83 11.86 2.35 5.58 2.62 2.18 3.78 1. 79 0.85 0.16 ...... -, 100.00

RHYOLITE (BCR) ~~ :-.

61. 34 10.11 19.78 1.04 1.55 4.07 0.81 0.73 0.12 0.86 100.39 RAD 67 61.63 10.16 19.87 1.04 1.55 4.09 0.81 0.72 0.12 100.00

62.74 10.35 2.26 16.18 1.06 1.58 4.16 0.82 0.73 0.12 100.00 ~

/' ~

,\

------" ....... _-~- .l.. ..... , "-:,.' ,~

.-.. ,.-.~ ,

...--'

EXTRUSlVE ROCKS (cont'd.)

STANDARD = BCR RHYOLITE (BCR) 0.00 = NOT DETECTED Fe 203 CALCULATED AS T102 + 1. 5% STANDARD = BCR-1 BLANK - NOT DETERHINED FOR DILUTION FACTOR • 66.667

~ /"---

SAMPLE 5102 A1 203 Fe.203 FeO MgO CaO Na20 K20 T102 P205 , LOI TOTALS

69.27 10.02 10.13 1.87 0.62 3.02 1.03 0.24 0.07 1.62 97.89 RAD 41 71. 95 10.41 10.52 1. 95 0.65 3.13 1.07 0.25 0.08 100.00

72.58 10.50 1.77 7.96 1. 97 0.65 3.16 1.08 0.25 0.08 100.00

72.22 8.48 9.22 2.02 3.32 1. 79 1.07 0.43 0.33 1.86 100.76 RAD 40 73. 03 B.57 9.32 2.04 3.36 1.81 1.09 0.44 0.34 100.00

73.58 8.63 1.95 6.69 2.06 3.39 1.82 1.10 0.44 0.34 100.00

INTRUSIVE ROCKS MAJOR ELEMENT CHEMISTRY

,;-GABBR~PYROlŒNITE DYKE

47.17 12.80 9.86 14.93 7.85 0.95 1.22 - 1.35 0.48 4.06 100.65 RAD 101 48.83 13.25 10.21 15.45 8.12 0.99 1. 26 1. 39 0.50 100. 00

49.22 13.27 2.92 6.65 15.58 8.19 1.00 1. 27 1.40 0.50 100.00

QUARTZ-DIORITE SrLL

50.11 12.94 20.39 5.63 3.58 2.32 0.34 1.71 0.11 3.10 100.23 RAD 75 51. 59 13.33 20.99 5.80 3.6.9 2.39 0.35 1. 76 0.11 100.00

52.51 13.57 3.32 16.25 5.90 3.76 2.43 0.36 1.79 0.11 100.00

55.79 - 12.95 17.33 1. 79 3.23 4.40 0.66 1.63 0.33 1.08 99.18 RAD 51 56.86 13.20 17.66 1.83 3.29 4.48 0.67 1.66 0.34 100.00

57.50 13.40 3.20 13.24 1.86 3.34 4.55 0.68 1.68 0.35 100.00

~

--~

M -.

..

r---' 1

INTRUSIVE ROCKS (cont'd.) -.. STANDARD = BCR QUARTZ-DIORITE SILL 0.00 = NOT DETECTED Fe 2°3 CALCULATED AS Ti02 + l. 5% STANDARD = BCR-l

BLANK = NOT DETERMINED FOR DILUTION FACTOR = 66.667

SAMPLE Si02 AI Z03 Fe2O) FeO MgO CaO Na20 KZO Ti02 P20S LOI TOTALS

56.64 12.81 17.17 2.30 3.68 3.79 0.38 1. 82 0.15 l.09 99.81 RAD 57 57.36 12.97 17.39 2.33 3.73 3.84 0.38 1.85 0.15 100.00

58.18 13 .15 3.40 12.82 2.36 3.78 3,89 0.39 1.88 0.15 100.00

GRANODIORITE

68.96 12.87 8.80 0.91 2.83 4.14 1.14 0.69 0.27 1.27 101. 89 RAD 49 68.54 12.79 B.74 0.90 2.Bl 4.12 1.13 0.69 0.2r 100.00

69.00 12.88 2.20 5.94 0.90 2.83 4.15 1.14 0.69 0.27 100.00

DOLERITE DYKE

49.41 13.41 20.53 4.63 3.06 3.56 1. 70 1.96 0.20 1. 68 100.13 RAD 50 50.18 13.63 20.85 4.70 3.11 3.61 1.73 1.99 0.20 100.00

51. 07 13.87 3.55 15.90 4.78 3.17 3.67 1. 76 2.03 O.ZO 100.00 , 61. 30 16.30 7.44 2.07 4.78 5.20 1.21 O.S} 0.07 1.63 100.57

RAD 48 61. 95 16.48 7.52 2.09 4.83 5.26 1. 22 0.58 0.07 100.00 62.28 16.57 2.09 4.93 2.10 4.86 5.29 1. 23 0.58 0.07 100.00

GABBRO-DIORITE DYKE ~

54.17 14.84 5.31 4.04 7.40 3.45 2.48 0.67 0.37 7.86 100.59 RAD 65 58.42 16. Dl 5.72 4.36 7.98 3.72 2.67 0.72 0.40 100.00

58.62 16.07 2.23 3.16 4.38 8.01 3.13 2.68 0.72 0.40 100.00

56.63 14.25 5.76 3.58 8.60 3.58 1. 49 0.66 0.32 6.16 101.04 RAD 46 59.69 15.02 6.07 3.77 9 . .07 3.77 1. 58 0.70 0.33 100.00

59.93 15.08 2.21 3.49 3.78 9.1.1 3.78 1. 59 0.70 0.33 100.00 ,',

'-----~-

i­l

'-'"

INTRUSIVE ROCKS (cont'd.)

ST ANDARD = BCR GABBRD-DIORITE DYKE

SAMPLE S102 AIZO)

57.48 15.07 RAD 2l 59.68 15.65

59.98 15.73

57.40 14.91 RAD 47 60.43 15.69

60.65 15.74

56.51 15.32 RAD 61 60.73 16.46

60.91 16.51

\

0.00 = NOT DETECTED BLANK = NOT DETERMINED FOR

Fe2O) FeO MgO CaO

7.00 3.76 6.89 7.27 3.90 7.16 2.23 4.57 3.92 7.20

5.20 3.43 6.08 5.47 3.61 6.40 2.17 2.99 -3.62 6.42

4.88 3.34 6.33 5.24 3.49 6.81 2.22 2.74 3.50 6.83

~

Fe 20) CALCULATED AS Ti02 .... 1.5% STANDARD = BCR-1 ! DILUTION FACTOR - 66.667 1

Na20 K20 Ti02 P205 LOI TOTALS

3.37 1.69 0.70 0.35 4.38 100.68 3.50 1. 76 0.72 0.36 100.00 3.52 1.77 0.72 0.36 100.00

3.90 3.10 0.63 0.34 5.65 100.64 4.10 3.27 0.66 0.36 100.00 4.11 3.28 0.66 0.36 100.00

3.51 2.18 0.66 0.42 4.74 97.79 3.77 2.34 0.71 0.45 100.00 3.78 2.35 0.71 0.45 100.00

• j

1· ----,.. .'"

--., ~

APPENDIX III-b TRACE ELEMENT GEOCHEMISTRY -=--EXTRUSrVE ROCKS

METAVOLCANIC (B1a) 0.0 = NOT DETECTED " AVERAGE OF TWO ANALYSES ~ " '-

SAMPLE Rb Sr Y Zr Nb Zn Cu Ni Mn Cr S

" " " " " RAD 44 17 11 42 89 7 90 18 15 1929 264 66

RAD 79 3 8 33 103 7 98 132 79 2118 187 76

* * * * * RAD 60 27 65 59 218 13 72 89 23 1117 20 278

RAD 80 318 65 100 327 19 95 125 39 1445 68 162

* * * * 31* RAD 52 11 5 53 233 13 64 22 15 1346 170

RAD 45 21 12 59 220 14 58 175 11 582 0.0 125

RADIORE RHYOLITE (RR) *(Metasediments or Tuffs)

RAD 55* 81 36 161 615 17 676 109 9 694 3 423

" " " * " RAD 54" 84 3 52 195 13 115 21 36 1503 17 279

RAD 66* 117 48 58 216 22 97 212 11 458 55 359

RAD 16* 161 13 48 131 15 76 551 20 379 49 1047

RAD 62 54 11 68 368 20 41 18 64 280 '\ 0.0 284

RAD 63 21 C 3 31 214 9 35 85 B 223 0.0 688

RAD 53 la 3 12 100 7 79 757 9 255 0.0 348

-. @')

~ . - . •

EXTRUSlVE ROCKS (cont'd.)

METAVOLCANIC (Blb) 0.0 = NOT DETECTED '" AVERAGE OF TWO ANALYSES

SAMPLE Rb Sr Y Zr Nb Zn Cu Ni Mn Cr S

" RAD 100 19 71 37 77 9 59 18 35 1014 41 66

RAD 30 72 - 43 53 166 10 355 88 12 869 18 207

RAD 43 21 118 78 240 11 68 25 11 1612 3 160

'" '" '" * * '" RAD 56 12 101 56 255 17 70 21 9 1413 13 220

RAD 58 19 104 78 280 15 77 22 13 1568 7 179

RAD 42 8 134 75 310 21 48 28 12 1303 0.0 125

RAD 64 32 83 36 451 12 30 14 8 432 1 141

RAD 59 10 67 92 340 19 32 109 11 569 0.0 487

RAD 78 53 100 72 354 20 32 67 9 441 6 154

RHYOLITE (BCR)

RAD 67 26 79 54 289 9 31 15 14 282 23 81

RAD 41 30 31 103 448 12 43 51 12 608 0.0 334

RAD 40 28 124 57 318 12 43 55 9 385 0.0 728

./

-...,

\ ~.;

\

INTRUSIVE ROCKS

GABBRO-PYROXENITE DYKE 0.0 = NOT DETECTED

SAMPLE Rb Sr Y Zr Nb Zn

RAD 101 29 50 108 83 13 45

QUARTZ-DIORITE SILL

RAD 75 12 200 50 100 9 120

* RAD 51 23 208 81 225 9 65

RAD 57 67 64 158 8 64

GRANODIORITE ~

RAD 49 33 141 81 230 13 37

DOLERlTE DYlŒ

RAD 50 69 43 49 105 8 104*

RAD 48 39 180 11 90 7 45

r-

I "

..... --,..~ ~ , ,

AVERAGE OF 'l'WO ANALYSES

Cu Ni Mn Cr

13 64 1045 132

62 49 2268 73

* * * 37 10 930 0.0

8 11 913 1

19 14 439 15

* * * * 25 33 2256 161

21 23 714 13

5

52

207

181

153

110

96

122

*

,-.., ,

/' -'

.. .- ~?

"

INTRUS IVE ROCKS (ccnt'd.)

GABBRQ-DIORITE DYKE

SAMPLE Rb Sr Y

RAD 65 60 458 15

RAD 46 39 1343 14

RAD 21 22 958 14

RAD 47 53 953 15

RAD 61 52 1264 13

.,. 4

, .-_-""~~ __ . - ~-... -'"T' __ .~...-_ '""' .... ""--.:-, '" __ ..., ............ ~ __ ..... ~

~~,

~~ """'~-:;.1 .. ------;--~ __

0.0 = NOT DETECTED

Zr Nb Zn Cu

192 8 171 14

212 7 75 18 ,

202 7 89 70

204 9 71 38

205 6 65 19

* AVERAGE OF. 'l'WO ANALYSES

Ni Mn Cr

68 901 H9

75 790 164

65 697 147 /

55 813/ 86

51 ~ 131 /

.- -.-- - ,-<' ~

~

•

S

311 i 843 • 201

569

388

v

~

- --~ ..... ~- ~ .. -,", -~~~ ... -- ....... ~-"~ -~

------- ~

APPENDIX III-c

COMPARISON OP MAJOR ELEI1ENT (WT%) AND TRACE ELEMENT (ppm) IN VOLCANIC ROCKS

TYPE 5102

A120 ) Fe2O) FeO MgO CaO Na20 K

20

1 1

IRAD 401 73.57 8.63 1. 95 6.69 2.06 3.39 1.82 1.10

IRHYOLITE2

74.42 11. 55 1.98 3.41 1. 29 1.47 3.68 1. 76

IRHYOLITE3 74.97 10 86 1. 82 3.59 1.17 2.18 3.57 1.49

RHYOLITE4 71. 80 13 10 1.L;-9 3.17 0.67 1.12 3.72 1.55

'DACITE5 68.80 13.10 1. 46 4.1l 0.89 2.91 3.45 1.23

'ANDESITE 6 56 60 14.60 2.50 7.25 3.48 5.92 3.17 0.86

IANDESITE 7 57.04 15 16 66 4.59 6.88 3.33 9.04 2.18 0.64 1

'RAD 1008 55.01 14.19 2.41 7.41 11.83 5.08 2.48 0.67

BASALT9 55.99 13.61 3.18 11.98 6.18 3.42 2.61 1.16 'BASALT10 51 71 15 99 3.19 10.24 5.86 9.13 2.32 0.24

BASALTll 50 05 13 07 4.74 12.27 5.37 8.54 3.39 0.18

IBASALT12 49.40 14.10 2.80 9.24 6.17 8.94 ~ 0.33

BASALT13 50 60 15.10 4.90 8.30 5.00 12.30 1.60 0.40

BASALT14 51.80 10.00 1. 33 9.04 11.90 8.56 1.52 0.85

1,8 This study. least altered samples RAD 40 (Rhyolite) and RAD 100 (Metavolcanic)

2 (BCR) , ) (NR) , 9 (BI), 10 (B2), Il (B3) MacGeehan 1979, Table 3.4 "Mean Composition of Vo1canic Rocks" (Matagàmi)

4,5,6,12, Goodwin, 1977, Table V, "Mean Composition of Vo1canic Rocks in the Superior Province, Canada"

7,13, Miyashiro, 1974, Table 8, Tholeiitic Andesite (Tongas) and Tholeiitic BasaIt (Kermades)

14, Condie et al., 1977, Table 1, "Mean Composition of Archean Tholeiites from Barbeton, South Africa"

** ppm

............. ~ .-- ....,.. ~ .... :1.l..;""""

~

Ti02 P205 MnO

0.44 0.34 385 ** 0.39 0.05 898 ** 0.31 0.04 798 ** 0.42 0.15 0.08

0.55 0.10 0.12

1. 20 0.31 0.18 I~! 0.78 0.13 0.19

-------0.90 0.03 1014 ** 1.66 0.21 1595 ** 1. 21 0.11 2138 ** 2.42 0.25 1743 ** 1.16 0.17 0.22

0.90 • 0.10 0.20

1.03 0.12 0.15

..

, ~ _ ... +--- _ ... - .... ...... ~. '--...-..,,- .... -~ -...... _- r --------- .... ~~---~- ,--- -~':'"'l

, """'" , --" "........ '-~..... 1-

'.

APPENDIX III-c (cont'd.)

TYPE Rb Sr Zr Y Nb Zn Cu Sn Co Rl V Cr Pb Ag S

RAD 401

28 124 318 57 12 43 55 9 n.d. 728

RHYOLITE2 380 ". 14 8 <20 15 <2

RHYOLITE3 445 12 9 <20 14 <2

RHYOLITE4 116 340 66 28 5.1 10 52 la 7.7 0.13

DACITE5 128 339 93 50 6.3 11 12 108 11 6.0 0.15

ANDESITE6 206 216 91 67 4.6 29 107 284 88 6.4 0.13

ANDESITE7

6 220 70 20 20 15

RAD 1008 19 71 77 37 9 59 18 35 41 66

BASALT9

<2

BASALT10

4 * 112 *' 70 * 24 * -6 .. 108 106 61 102 227 146 <2 560

BASALTll /3 .. 159 .. 44 .. 55 .. Il * 81 41 57 50 380 41 <2 570

BASALT12

149 lOB 99 105 4.B 38 162 385 256 4.8 0.34

BASALT13 5 200 70 30 270 50

BASALTl4

15 200 194 14 14 96 139 72 750 1204

1,8 This study least altered samples RAD 40 (Rhyolite) and RAD 100 (Hetavolcanic)

2 (BCR), 3 (NR) , 9 (BI), 10 (B2), 11 (B3) MacGeehan 1979, Table 3.4 "Mean Composition of Vo1canic Rocks" (Hatagaud)

4,5,&,12, Goodwin, 1977, Table V, "Mean Composition of Volcanic Rocks in the Superior Province, Canada"

7,13, Miyashiro~ 1974, Table 8, Tholeiitic Andesite (Tongas) and Tho1eiitic BasaIt (Kermades)

14, Candie et al., 1977, T.lble l, "Mean Composition of Archean Tholeiites from Barbeton. South Africa"

*Courtesy Dr. MacLean (Unpublished data) not reported

n.d. : not detected

r /

(

- 138 -

APPENDIX IV

STATISfIC

.... - ....... n l' ......

.) Elementary statistic and correlation coefficient have been

ca~ed dut using STATPAK statistica1 program available at McGill \~ -University in WhlCh statistical and data-manipulation analyses are

available in a conversational fo~ 4~gned to be used by people wi:h . . h J,y 11 ttle experience Wl t computers. ~'«

STATPAK treats the data as a matrix in which the columns are

variables (geochemical elements), and the rows are cases (samples). 1

For example, if one has to reco~d four samples gold and si1ver, the

data are arranged as follows:

Au Ag

Samp1e 1 0.15 6.2

Sample 2 0.37 4.7

Samp1e 3 0.69 12.9

Sample 4 0.51 8.4

STATPAK can deal,with no more than lS variables at a time and' a

maxinrum number of cases is 600. However, the total "number of elements

cannat exceed 1200. According1y, one is limited to l~OO/lS = 80 (1200/

gea~émica1 elements = samples) or similarly 1200/600 = 2 (1200/samples

= ~eachemical elements).

In order ta use STATPAK one has to become acquainted with MUSIC,

a tirne sharing system which enables the user ta enter STATPAK.

Cr

,

1 ; .

I-I

\

.1 1

~\

- 139 -

Infonnation about MUSIC is contained in an lI1troductory manual

"The Music Student Guide" and more infonnation is contained in a

separate publication "The Music User' s Guide" both available at Burnside

Hall at McGil1 University.

ELEMENTARY STATISTICS

For each variable (Le. colurrm of the data matrix), the mean

value, standard deviation, standard error, maximum value, minimum value

(and range of values is printed. The comp\ltational procedures are as

below:

Means:

, \ n

xj = l ,xij i=l '\

n

where n = number of samples j = 1, 2, ... ,m are variables (geochemical element)

Standard Deviations: ;

where n n ]

s .. = [ ex .. -xl

·)2 - L (x .. -xl·) 2

JJ i=l 1) J i:::l 1J J -----_-..!=.

n

\ , \

'"

\ \

'1'

j

1

-1,

r ( , •

,

1 t

·1

1

i , r ,

f 1 ,

) 140 -

Standard Errors of Means:

s -x· J

Ranges:

s· = J

R. = MAX. - MIN. J J J

where Mt\X. and MIN. are the maximum and minimum values of the j-th Jvariable~

CORRELATION (Pearson's Product Moment Correlation Coefficients)

A correlation coefficient is a measure of association between two

variables. When the correlation coefficients are computed among many

variables, these values are usually presented in the form of a matrix.

The CORRELATION analys,is computes a product moment correlation

coefficient between each pair of variables. A correlation matrix is

printed wherein the ij-th element is the correlation coefficient between

the i-th and j-th variables. The coefficients are computed as outlined

below: "

Let x' .. denote input data, where i :l 1,2, ... n are spmples 1J 1 -

and j = l, 2, '.' . mare geochemical elemen ts. The following

equations are used to calculate correlation coefficients:

Sums of cross-products of deviations:

n

\

i "

, 1

"

1

, !

1. j

1

1

1 f 1

c

\

() ~,.

, ,

- -~''''fII!,...,. .. ! .. _"~t::_ .. ~ .. - p , ... ,~.,._, ... -~~ .. _

- 141 -

where j,k=!,2, ... ,m

Correlation coefficients:

Sjk T jk = -------

'V5.'. JJ

.'

l

1

l

-----te: 1

APPENDIX V RADIORE SAMPLES LIST

c Z w u u.: 0 J: w lolo

SAMPlE DIAMOND ROCK MAP VI II') ë 1- -..... 0 ORILL:'CORE TYPE LOCALITY u 2 ~ ....: . w w

<t VI 1 :x: 0:: Z z II') c::: . .

<t ..... , >< J: J: 0 X , "l- I- a..

RAD 1 MASSIVE ORE l'>1AP 5 fi) •

RAD 2 MASSIVE ORE l\1AP 5 • • RAO 3 MASSIVE ORE BAP 5 ®

RAO 4 RHYOLITE CRR) r-rAP 5 G

RAO 6 RHYOLITE (RR) MAP 5 El) (il)

RAD 7 RHYOLITE (RR) MAP 5 Q •

RAO 8 MASSIVE ORE MAP 5 • RAD 9 RHYOLITE (RR) ~1AP 5 • ct

, • RAO 10 METASED(Blb) MAP 5

RAD 12 MASSIVE ORE MAl' ~ • RAO 13 ,4ASSlVE ORE r-1AP 5 • • •

1 .t RAD 14 MASSIVE ORE MAP 5 • RAD 15 llliYOLITE (RR) MAP 5 • RAD 16 METASED CRR) ~1AP 5 • • RAD 17 MASSIVE ORE ~1AP 5 • RAD 18 MASSIVE ORE MAP 5 • • RAD 19 MET ASED (RR) MAP 5 • RAD 20 METASED(Blb) MAP 5 • RAD 21 DIORITE DYIŒ ~1AP 5 • •

( , - RAD 22 MASSIVE ORE f\1AP 5 • •

/

APPENDIX V (cont'd.) RADIORE SAMPlES LIST

0 z w U u. 0 J: w u.

SAMPLE DIAMOND ROCK MAP 11'1 11'1 CS ... ::ï DRILL-CORE TYPE LOCALITY v 0 Q

> L.r..: . w W 11'1 e:\. :::t: ~

. ct 1 Q:: z Z 11'1 et:

. . ~ i

...1 1 >< J: 0 >< Jo- ..... e:\.

RAD 23 HI\SS IVE ORE ~!AP 5 .. •

RAD 26 RHYOLITE (RRJ MAP 5 • • RAO 27 HASSIVE ORE MAP 5 " • RAO 28 RHYOLITE CM) MAP 5 G --RAD 29 MASSIVE ORE MAP 5 •

,

RAO 30 METI\VOL (Blb J MAP S • .,/

RAO 31 RHYOLITE (RR) t-.1AP 5 • RAO 32 MASSIVE ORE MUCK-PILE • RAO 33 MASSIVE ORE MUCK-PILE • RAO 34 MASSIVE ORE MUCK-PILE • RAD 3S MASSIVE ORE MUCK-PILE • RAD 36 MASSIVE ORE MUCK-PILE • RAD 37 MASSIVE ORE MUCK-PILE • RAD 38 MASSIVE ORE MUCK-PILE • RAD 39 MASSIVE ORE rvuCK-PILE • RAD 40 EE-34 106' RHYOLITE (BCR) t-.1AP 3 • RAD 41 UR-I2 469' RHYOLITE (BCR) FIG. 2.2 • RAO 42 UR-I2 74R' METAVOL (1nb) FIG. 2.2 • RAD 43 UR-12 825' METAVOL (BIa) FIG. 2.2 •

i RAO 44 UR-12 1673 METAVOL (Bla) FIG. 2.2 • •

(

J 1 ..

APPENDIX V (cont'd.) RADIORE SAMPLES LIS'T

c z w 0 :r:

SAMPlE ROCK V1 DIAMOND MAP 1- ::::ï DRILL-CORE lQCALlTY u 0 TYPE w Q. V1

1 , Z Z - l: :r: l- I-

RAD 45 UR-12 2075 METAVOL(Bla) FIG. Î Î '-.-RAD 46 UR.-12 1113 GAB/DIOR DYKE FIG. 2.2

RAD 47 UR-12 1167 MJN/DIOR DYTI FIG. 2.2

RAD 48 UR-12 19' DIABASE FIG. 2.2 • 0

RAD 49 UR-12 1966 MI CROGRANlTE FIG. 2.2

RA050 UR-12 275' DIABASE FIG. 2.2 " RAD 51 EE-34 15' OlJARTZ-DIORITE MAP 3

.. UNDERGROUND

RAD 52 UR-8 369' METAVOL CBla) DRILL-HOLE

RAD 53 EE-34 322' RHYOLITE (RR) MAP 3

UNDERGROUND RAD 54 UR-6 107' METASED(RR) DRILL HOLE

RAD 55 EE-18 318' METASED CRR) MAP 2 • RAD Sn UR-IO 109' METAVOLCBlb) MAP 3

RAD 57 EE-37 531' OUARTZ-DIORITE -

RAD 58 UR-IO 74 ' METAVOL(Blb) MAP 3

RAD 59 EE-34 202' METAVOL(Blb) MAP 3 • • RAD ÔO EE-16 167' METAVOL (Bla) HAP 3 • RAD 61 UR-8 244' DIORITE DYKE HAP 2

RAD ô2 EE-16 262' RHYOLITE CRR) MAP 3 • RAD 63 EE-16 249' RHYOLITE CRR) MAP 3 • RAD 64 EE-18 211' METAVOLCBlb) MAP 2 • •

U u.: w ... V1 ë c > u.: . W

<l: :r: < 0::: ~ et: . .

<l: """ 1 X 0 >< Q.

• • • fi

• CD

• • • • • • • • • • •

• • • •

• •

• • •

- 1-

( APPENDIl v (cont' d. )

RADIORE SAMPLES LIST Cl

Z u.a u u.: 0 J: u.a u..

SAMPlE DIAMOND ROCK MAP '" '" 5 1- ::::i DRILL-CORE TYPE LOCALITY u 0 Cl JJ.: . w c.. u.a

~ ct VI 1 J: ct: Z Z !!! 0::

. . ct - 5:

...a 1 >< J: 0 X 1- ~ c..

RAD 6S EE-34 6~' .) CAR/IHOR DYKE ~!AP 3 • • • META.SED (RR)

IuNDERGROUND • RAD Ci6 UR-l 111' DRILL-HOLE

RAD 67 EE-18 177' OUARTZ-EYE (BCR M\P 2 ., • • •

UNDERGROUND • RAD 68 UR-Z 51' METAVOL (B1b) DRILL-HOLE

RAO 69 UR-8 177' METAVOL(Blb) MAP 2 " RAD 70 EE-16 222' METAVOL/GAB MAP 3 • RAD 71 UR-12 468' RHYOLITE (BCR\ FIG. 2.2 • RAD 72 UR-12 611' RHYOLITE (BCR) FIG. ') ') • 1...._

RAD 73 UR-12 1075 CABBRO-DIORITI FIG. 2.2 • • RAD 74 UR-12 1093 GABBRO- D IOR III FIG. Z.Z • RAD 75 UR-12 1453 OUARTZ-DIORITI FIG. 2.2 • • • RAD 76 UR-lZ 1880 METAVOL(Bla) FIG. 2.2 • • RAD 77 UR-12 2040 META VOL (BJ a) FIG. 2.2 • •

-RAD 78 UR-12 688 RHYOLITE (BCR) FIG.: 2.2 • • • ,

RAD 79 UR-12 1738 METAVOL (Ela) FIG '7 2 • • RAD 8n UR-12 1898 METAVOL(Bla) FIG. 2.2 • RAD 81 UR-12 2057 ~1ETAVOL(Bla) FIG. 2.2 • RAD 82 UR-12 1693 METAVOL(Bla) FIG. 2.2 • • , RAD --

( RAD "

(

( APPENDIX V (cont'd.)

RADI OR~ SAl\tlPLES LIST Cl

Z Uo.I U u.: 0 :J: Uo.I ~

SAMPlE DIAMOND ROCK MAP VI VI 5 1- .....1

DRILL-CORE LOCALITY u 0 Cl > LJ.: . TYP E w c.. w « VI

1 :J: « 0:::: z Z !!! 0:: . . « .....1 , X :r :J: 0 X 1- .... 0..

RAD 100 METAVOL.(B1b) MAP 1 • • • RAD 101 GABBRO-PYROX MAP 1 • • • RAD 102 rJUARTZ-DIORITE fv1AP 1

., GD

RAD

RAD

RAD

RAD

RAD

RAD 1

RAD

RAD

RAD

RAD

RAD

RAD

RAD

RAD

RAD

1 RAD

RAD

\~ ------_/

,~----

rn [Z] llTI[J

L[GoEND

0"."1 DI.,'t. 5U1 (.)FI" •• ,.tA Q".,II-OI ... II.

ihn Clleft"_t Rh,,_lIt .. (BCR )

NI.t.ulce,,'. (011t)

Radiore Geology

~ < ' -

y,:~ RR ...

" ,',,': ,~/,,:,: \'~-:::>\' ':--~'-'.'~<'::-~7·· " ) " -,': ':":' .:,! l '_ ,.1- ," ~,: ' ... , .. ,~,:' ,_ ,', '1":\,'

,', '-''''';,~ ',' \ '" -:,'-~,,:-;,~:,'~:"(',I'~~.~~,,-,-

" NR ",l,

,l, -

ffi ~ D o o o

M ••• t",.R",.tUe

~"

10 0 10 20 ~-.~-~I--

IQ 40 SOm -- ._:::1

Map 1

i

',,::",' .' ~;, ' /_ 1

, ,'i

G ..

L.S. 1- 50 E

r

{ "

.... ....... .. ... ...... .. .. ~ ..

~ .. .. .... .. ~.. ..... . :~:~~~~((

Map2

Il ... • ...

, ' . ,

ï

L.gond

c:J Gabbro-Dlorlt. D~k.

r::z::JF"ln. and C ••••• Qulnad Qa.[)lo"'.

G]!';J BoU ChannoU Rh)"otlt. (BeR) a) QI.o,.. "")"0111.

CJ M.uvole.nlo (8Ib)

_ M ... I ... Sulllhid. Or.

c::.J R.dlo,. Ah~ollt. (RRI

~ M.t •• oIunla (1I1a)

~ drlll-hoi.

o •• mlli. 10"aUon

seAU

'.'~'~' .. ~'-' .. --" .. ~-----"-

L.S. 1-e5E

1 'Bl". -1-, 1

1 i , 1 t [ 1 j 1

, \

.2; ..

\

Map3

L.gond

c::J Cabbro-Dlorlt. Oyk.

C3 Fln. and COO"" , .. IMd Qa.O'.rlt.

[l[J 8.11 Channell Rhyollt. (ae", a) Qz •• ,."hYOllt.

c.:=J M.ta_.I.onla (81b)

_M ... l .. Sulphlde Or.

c::J R.dl ... "hyollt. (RR)

C3 Mot._oIoonlo (81.,

" drlll-hoi. "" ... o ...... ,. loootl."

SCAU

• ........................ .a •• ~

\

(

\

RADIORE ~2 MINE

~ \ \Portal

------~~----+_----------K)700 N

Ramp

N.

f

! w ~ o o _____ ~+------10SOO N

(a)

Venltrohon Ra ...

--J$.-; .-

(c) "'

0::;

'" o o

/~

Leve! n'l (2991)

w 'lI ~,

.. --_ .. _---- _ ..... --- ..... _-------, " " " \' \\

\' ,\ " " \ ,

\ \ , , , , , , V.n'Ilotion Ran. '\ \

( b)

(d)

, \ \ \

\ \ \ \

'~-~-~4:==::;:~~~::~ 1...______ ..... _J .... _

'" o o o

\ ,'r-

( :_\ \,

Transport On

V.ntilation Ra; •• _" -<c----

(5

~ 'W=1ê '~--df'" 0-o o

RADIORE N'2 MINE Map4 N

OO'N l w

Ramp

I1p

_____ 10300 N

ca.ion

Level n'l (2991)

~--------------------------- --Ov.rburden -- --- ------__________ _

g (b) o

E

Level 0'2 (2965 )

'M? 10 20 30 10 ;pm Longitudinal Section

(d)

\ \ ir', "

t. +' '-:. I

D ... ",

\

1 r \'\ "\ \, "', \ \ \ ,Ramp , \ "

f'

_______ + ___ --_'.!.' ,.:-'.:-, ___ '0300 N

"\ '\.'1

Ventila,ion 10 ... ---<-~

{\.'..::-.:.---_-.:::::;:::--,

(5 0-o o

\. \'\ , '\ , , , . \ .... ,

Level n' 2 (2965)

... ' '"'J (

c

...

ln

;:-----

, __ ; ~ ~.: ,", ,

, ~'_·~~::'~-~-4~~{-' -; ~' '.:..~~.~

MINf RADIORf 2

1-00 l 1_25 f

(

\ . ')

. \

Abitibi Project

McGILL UNIVERSITY

" , . \

RAD.I 0 RE '2' MIN E level No 1

_.

+ +

1_50 r

1

/

Map 5

( 1 , 1

~ Legend

Cl Gabbro - Dlonte Dyke

0 Metavolcilnlc CBlbJ

C3 Banded Massive Su Iph,de (and Chiant

Q Coarse Gramed Ma,>slve Sulphtde(a)

0 Massive Stltceoù's Ore 1

D Massive RhyolIte

0 Tults or Metasedlments

fi'

+ +

1_75 [ 2-00 [

1

1

j

, \ 1

---~

Map 5

Legend

E:J Gabbro - Dlonte Dyke

D Metavolcanlc (BIbl

Cl Banded Massive Sulphlde< and Chlonllzed Fragments)

o Coarse Gramed Ma'iSlve Sulphlde(a) MetasedlmentsCbl

o Massive S,ilceous Ore

D Massive Rhyolite

o TuHs or Metasedlments

+

2-00 f

1 0 , 2 , 4 5 10 ... ioool" .. -_-__ ........ -~-......

....... " 1.'0

ft

,(

)