Precambrian Geology, Northern Swayze Greenstone Belt

Precambrian Geology Northern Swayze Greenstone Belt

Ontario Geological Survey Report 297

1995

1 2 Precambrian Geology Northern Swayze Greenstone Belt

Ontario Geological Survey Report 297

J. A. Ayer

1995

CANADA ONTARIO This publication was funded under the Minerals program of the EDNO ¥ Northern Ontario Canada-Ontario Northern Ontario Development Agreement (NODA), Development Agreement Entente de développement du nord de l'Ontario a four year joint initiative signed November 4, 1991.

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Canadian Cataloguing in Publication Data

Ayer, John Albert Precambrian geology, Northern Swayze Greenstone belt

(Ontario Geological Survey report, ISSN 0704-2582; 297) Includes bibliographic references. ISBN 0-7778-3813-3

1. Geology-Ontario-Swayze Region. 2. Geology, Stratigraphic-Precambrian. 3. Greenstone belts-Ontario-Swayze Region. I. Ontario. Ministry of Northern Development and Mines. II. Ontario Geological Survey. III. Title. IV. Series.

QE191.A93 1995 551.7’1’09713133 C95-964027-4

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Ayer, J.A. 1995. Precambrian geology, northern Swayze greenstone belt; Ontario Geological Survey, Report 297, 57p.

Critical Reader: P.C. Thurston

Edited/Produced by: Geomatics International Inc.

ii Contents

Introduction ...... 3 Mineral Exploration...... 3 Previous Geological Work ...... 4 Present Geological Survey...... 4 Acknowledgments ...... 4

General Geology ...... 6 Archean ...... 7 Ultramafic Metavolcanic Rocks ...... 7 Mafic Metavolcanic Rocks ...... 8 Intermediate Metavolcanic Rocks ...... 9 Felsic Metavolcanic Rocks ...... 9 Clastic Metasedimentary Rocks ...... 10 Chemical Metasedimentary Rocks ...... 10 Metamorphosed Ultramafic Cumulate Rocks ...... 11 Metamorphosed Mafic Intrusive Rocks ...... 12 Felsic to Mafic Plutonic Rocks...... 12 Kapuskasing Structural Zone ...... 13 Nat River Granitoid Complex ...... 13 Kenogamissi Batholith ...... 14 Tom Smith Lake Granitic Complex ...... 14 Kukatush Pluton ...... 15 Hoodoo Lake Pluton ...... 15 Ivanhoe Lake Pluton ...... 16 Alkalic Mafic Intrusive Rocks ...... 16 Proterozoic ...... 16 Mafic Intrusive Rocks ...... 16 Phanerozoic ...... 17 Pleistocene and Recent ...... 17 Metamorphism ...... 17 Alteration ...... 18 Silicification ...... 18 Chloritoid-bearing Volcanic Rocks ...... 18 Carbonatization ...... 18 Epidotization ...... 18

Geochemistry...... 20

Structural Geology ...... 43 Kapuskasing Structural Zone ...... 43 North Swayze Greenstone Belt Zone ...... 43 Folding ...... 43 Faulting ...... 44 Ductile Faults ...... 45 Brittle-Ductile Faults ...... 45 Brittle Faults ...... 45

Economic Geology ...... 46 Gold ...... 46 Arkell ...... 46 BHP-Utah Mines Limited ...... 46 B.P. Resources Limited...... 46 Bromley...... 47 Card Lake Copper Mines Limited ...... 47 Hoodoo-Patricia ...... 47 Joburke Mine ...... 47

iii Johnson Wright ...... 48 Jonsmith ...... 48 Kalbrook ...... 49 Little Long Lac Gold Mines Limited ...... 49 Mining Corp ...... 49 Nib Yellowknife ...... 49 Tremblay ...... 49 Unigold Resources Limited ...... 49 Copper and Zinc...... 50 Dome Exploration ...... 50 Hudbay Mining Limited ...... 51 Karvinen ...... 51 Keevil Mining Group Limited ...... 51 Noranda Exploration Company Limited ...... 51 United MacFie Mines Limited ...... 51 Nickel and Platinum Group Elements ...... 52 Akweskwa Lake ...... 52 Amax Minerals Limited ...... 52 International Norvalie ...... 52 Ireland ...... 52 McIntyre Johnson ...... 52 Norduna...... 52 Iron ...... 53 Nat River ...... 53 Radio Hill ...... 53 Asbestos ...... 53 Reeves Mine ...... 53 Talc ...... 54 Penhorwood Mine ...... 54 Barite ...... 54 Cryderman Mine ...... 54 Silica ...... 54 Horwood Mine ...... 54 Roseval Mine ...... 54

References ...... 55

Metric Conversion Table ...... 57

FIGURES

1. Key map showing the location of the synoptic area...... 3

2. General geology of the northern Swayze greenstone belt...... 6

3. Jensen cation plot of ultramafic volcanic samples...... 20

4. Chondrite-normalized REE plot of ultramafic volcanic samples...... 20

5. Jensen cation plot of mafic volcanic samples...... 21

6. Chondrite-normalized REE plot of mafic volcanic samples...... 21

7. Jensen cation plot of intermediate to felsic volcanic samples...... 22

8. Chondrite-normalized REE plot of intermediate to felsic volcanic samples...... 22

9. Jensen cation plot of ultramafic cumulate and gabbroic samples...... 22

iv 10. Chondrite-normalized REE plot of samples from the Reeves ultramafic to gabbroic body...... 23

11. Chondrite-normalized REE plot of samples from the ultramafic to gabbroic body hosting the Ireland nickel showing...... 23

12. Jensen cation plot of altered mafic volcanic samples from the Joburke Mine. .. 24

13. Chondrite-normalized REE plot of altered mafic volcanic samples from the Joburke Mine...... 24

14. Pearce and Cann plot of volcanic samples from the northern Swayze greenstone belt...... 24

15. Pearce and Cann plot of altered mafic volcanic samples from the Joburke Mine...... 24

TABLES

1. Lithologic units for the northern Swayze greenstone belt...... 7

2. Lithogeochemical sample descriptions and locations...... 25

3. Whole-rock geochemical data from Foleyet and Ivanhoe townships...... 28

4. Whole-rock geochemical data from Muskego and Keith townships...... 34

5. Whole-rock geochemical data from Reeves, Penhorwood, Sewell and Kenogaming townships...... 37

GEOLOGICAL MAPS

Map 2627 - Precambrian Geology, Northern Swayze Greenstone Belt ...... back pocket

v Abstract

This report is a synopsis and compilation of the geology of Foleyet, Ivanhoe, Muskego, Keith, Reeves, Penhorwood, Sewell and Kenogaming townships at a scale of 1:50 000. It covers most of the northern Swayze greenstone belt within the southwestern part of the Abitibi Subprovince and a small part of the eastern margin of the Kapuskasing Structural Zone.

The oldest rocks in the area consist of northeasterly trending paragneiss and amphibole gneiss, intruded by both the Shawmere anorthosite complex and granitoid gneiss, within the Kapuskasing Structural Zone, on the western margin of the synoptic area. Tonalite gneiss associated with the Shawmere complex has been dated at 2765 Ma. Kapuskasing Structural Zone rocks have been metamorphosed to granulite facies conditions and are interpreted to be a segment of Archean lower crust thrust eastwards over the Abitibi Subprovince along the Ivanhoe Lake cataclastic zone.

East of the Ivanhoe Lake cataclastic zone, the northern Swayze greenstone belt consists of easterly trending supracrustal rocks subdivided into 3 distinct assemblages. The MuskegoÐReeves assemblage in the northern part of the belt consists of mafic flows intercalated with ultramafic volcanic flows, iron formations, clastic sedimentary rocks and localized accumulations of intermediate to felsic flows and pyroclastic rocks. Conglomerate, wacke and mudstone occur in an extensive clastic sedimentary unit in the uppermost stratigraphic reaches of the MuskegoÐReeves assemblage in the northwest part of the belt. The Horwood assemblage lies to the south. It consists predominantly of tholeiitic mafic flows with minor intercalations of fine-grained clastic sedimentary rocks, calc-alkalic pyroclastic rocks and ultramafic flows. The Hanrahan assemblage consists of intermediate to felsic pyroclastic rocks and flows capped by iron formation, within the Hanrahan antiform in the southeast part of the belt.

Extensive sill-like bodies of massive, medium-grained, cumulate-textured ultramafic rock occur in all the assemblages. Locally, in the MuskegoÐReeves assemblage, the cumulate- textured ultramafic units grade along strike into ultramafic flows and thus may represent proximal-facies flows or feeder intrusions. Differentiation into an uppermost gabbroic unit occurs in the northern part of the Reeves ultramafic body.

Granitoid intrusions include both early foliated and late massive rock units. Early intrusions tend to be more sodic and are predominantly tonalite and granodiorite. They are most abundant in the large granitic complexes outside the supracrustal sequence, including the Kenogamissi batholith, the Nat River granitic complex and the Tom Smith Lake granitic complex. Smaller, early intrusions of foliated porphyry, granodiorite and granite occur within the supracrustal assemblages. Late intrusions include bodies such as the Ivanhoe Lake, Hoodoo Lake and Kukatush plutons, within the supracrustal rocks, and parts of the larger external granitic complexes mentioned above. Late granitic phases consist predominantly of massive to weakly foliated granodiorite, granite and monzonite, with minor diorite, syenite, gabbro and clinopyroxenite. Late intrusive phases of the Tom Smith Lake granitic complex and the Hoodoo Lake pluton have been dated at 2680 and 2684 Ma, respectively.

Lithogeochemical data indicate the mafic volcanic rocks are magnesium and iron tholeiites. The tholeiitic mafic and the komatiitic ultramafic flows are depleted in light rare earth elements, suggesting derivation from a long-term depleted ensimatic Archean mantle at a constructive plate margin. These geochemical patterns are most similar to those of modern basalts formed at mid-oceanic ridges. The intermediate to felsic volcanic rocks are calc-alkalic with highly enriched light rare earth elements. They were most likely derived from destructive plate margins associated with Archean island arc environments. The cumulate-textured ultramafic bodies have geochemical patterns which suggest an origin common to that of the ultramafic flows.

vi Polyphase deformation has resulted in at least 5 separate fabric generations. Generations D1 to D3 are related to regional folding events, with or without associated ductile deformation. Generations D4 and D5 are spatially associated with regional shear zones and are interpreted to be related to late ductile deformation. Three distinct generations of faulting are distinguished. Faults associated with D4 and D5 are designated as ductile and brittle-ductile faults. Late northerly trending brittle faults are Proterozoic in age and may be associated with the Matachewan diabase dikes.

A number of significant gold occurrences and a past-producing gold mine indicate good potential for gold mineralization in the northern Swayze greenstone belt. The Joburke mine produced about half a million tons of ore grading approximately 0.11 ounce Au per ton. All of the gold mineralization is spatially associated with ductile deformation zones. Typically the mineralization occurs in quartz veins in highly deformed and carbonatized mafic volcanic rocks.

Two types of exhalative copper-zinc mineralization are present in the area: 1) localized concentrations of sphalerite and chalcopyrite within sulphide-facies iron formations; and 2) lenses of strata-bound, massive to disseminated sulphides with minor sphalerite and chalcopyrite, in sequences containing calc-alkalic felsic, tholeiitic mafic and komatiitic ultramafic volcanic rocks. Hydrothermal alteration consisting of chloritoid-bearing volcanic rocks and silicification is locally associated with the stratabound sulphide mineralization.

Potential may also exist for magmatic nickel-copper-platinum group element deposits. Documented occurrences are predominantly associated with the ultramafic cumulate bodies in the Hanrahan assemblage. Asbestos and talc are also associated with the ultramafic rocks. Two ore bodies occur in the Reeves ultramafic unit. The Reeves asbestos mine produced about 140 000 tons of asbestos and the Penhorwood talc mine is currently milling 450 tons per day of talc. Industrial minerals, including barite and silica, have been produced from veins closely associated with granitic intrusions in the Hardiman deformation zone, in southwestern Penhorwood Township.

Ayer, J.A. 1995. Precambrian geology, northern Swayze greenstone belt; Ontario Geological Survey, Report 297, 57p.

vii viii Precambrian Geology Northern Swayze Greenstone Belt

J. A. Ayer

Geoscientist, Precambrian Geoscience Section, Ontario Geological Survey.

Report approved for publication by B. Dressler, Section Chief, Precambrian Geoscience Section, Ontario Geological Survey. This report is published with the permission of John Wood, Director, Ontario Geological Survey.

1 OGS REPORT 297

2 3 OGS REPORT 297 an estimated 27 million tons of 29% total iron in the Nat tion derived from the detailed mapping outlined above, River iron formation in Penhorwood Township. A third previous mapping projects and from data contained in iron formation extends about 10 km with an east-northeast mineral exploration files. Exploration work filed for trend across the north-central part of Keith Township. This assessment credit is on file at the Resident Geologist’s iron formation, identified as the Palomar iron formation, office in Timmins and is now available in a summarized has been explored by a number of companies but as it is format in Geological Data Inventory Folios (GDIF) for all relatively thin throughout its length, resource tonnage figures of the 8 townships across the NSGB. were never calculated. Diamond-drill core stored at a number of locations in Timmins, including the Ministry of Northern Develop- PREVIOUS GEOLOGICAL WORK ment and Mines drill core library, and at Falconbridge Limited and Placer Dome Canada Limited, was examined The earliest geological reference to the map area is by and in some places sampled. Diamond-drill hole locations Parks (1900) who produced the first map of the area sur- were derived from the GDIFs available as open files in the rounding Ivanhoe and Horwood lakes. Tanton (1917) out- Resident Geologist’s office, Timmins, and from the relevant lined the distribution of the “greenstones” in the map area company files for those holes not located on the GDIFs. in a reconnaissance survey along the Canadian National The geological coding of rock units which were not directly Railway (CNR) line between Gogama and Oba. A geolog- observed by the author have been derived from the drill ical map by Harding (1937), at a scale of 1:63 360, included logs and are prefixed by the letter “D” on Map 2627 all of Ivanhoe and Keith townships and the southern third (back pocket). of Foleyet and Muskego townships. A regional-scale mapping project, published at a scale of 1:250 000 by Thurston et al. (1977), included all of the map area. The western Geological data were recorded in the field on acetate half of the map area is also included in a 1:100 000 scale overlays superimposed on 1:15 840 scale aerial photo- map by Percival (1981). graphs. The data were subsequently transferred to cronaflex base maps prepared by the cartography section of the Previous detailed mapping, predominantly conducted Ontario Ministry of Natural Resources. at a scale of 1:15 840, covered substantial parts of the map area and includes 1) the northern half of Keith Township Data from airborne total intensity and electromagnetic and the southern part of Muskego Township by Prest surveys (OGS 1990) were utilized to derive colour-contoured (1951) at a scale of 1:12 000; 2) Reeves, Penhorwood, magnetic susceptibility and vertical derivative maps. Sewell and Kenogaming townships by Milne (1972); 3) These maps enhance subtle geological and structural features the southern half of Keith Township by Breaks (1978); and and greatly aided in geological interpretation, particularly 4) the northwestern part of Foleyet Township by Riccio in areas with extensive overburden cover. The geological (1981). coding of units interpreted from the geophysical maps are The area was covered by an airborne magnetic survey prefixed by the letter “G” on Map 2627 (back pocket). at a 400 m line spacing and was published in 1963 at a scale of 1:63 360 (ODMÐGSC 1963a-d). A higher resolu- A number of regional-scale geological projects tion airborne magnetic and electromagnetic survey at a focussing on the Swayze greenstone belt are also currently in 200 m line spacing includes the parts of the map area progress. These are as follows: 1) a mineral deposit study underlain by supracrustal rocks and was published at a (Fumerton 1992, 1993); 2) surficial geological mapping scale of 1:20 000 (OGS 1990) and drift geochemistry (Kaszycki 1992; Bernier and Goff 1993); 3) a regional-scale bedrock mapping and geochronology study (Heather 1993; Heather and van PRESENT GEOLOGICAL SURVEY Breemen 1994); and 4) computer-assisted compilation and analysis of a wide range of digital data using Geographic This synoptic report is part of a continuing project to Information System technology (Harris et al. 1994). update the geological database of the northern Swayze greenstone belt (NSGB). The initial phases of the project were funded by the Northern Ontario Development ACKNOWLEDGMENTS Agreement (NODA) and were focussed on detailed mapping (1:15 840 scale) of Foleyet and Ivanhoe townships in 1991 (Ayer 1993), and Keith and Muskego townships in 1992 M. Puumala and R. Theriault served as senior assistants in (Ayer and Theriault 1992). Reeves, Penhorwood, Sewell 1991 and 1992, respectively. Their contribution to the map- and Kenogaming townships were investigated in 1993, ping and the development of geological concepts applied with detailed mapping at a scale of 1:20 000 focussed on to the resulting map is very much appreciated. S. Beauchamp, specific areas with regard to special geological, structural, C. Lang, T. Searcy, Y. Rappaport, T. Hearty, S. Connell geochemical or metallogenic problems. The accompanying and S. Morrison are gratefully acknowledged for their synoptic geological map (Map 2627, back pocket) is at a capable assistance as junior assistants during the 3 years of scale of 1:50 000 and represents a compilation of informa- mapping.

4 NORTHERN SWAYZE GREENSTONE BELT

Appreciation is also extended to the staff of the Resident Cominco Limited are thanked for access to diamond-drill Geologist’s office and drill core library in Timmins for logis- core and proprietary exploration data, and for many fruitful tical support. Members of the geological staff of Noranda discussions about the geology of the synoptic area. I would Exploration Company Limited, Falconbridge Limited, Placer also like to thank G. Ross of Foleyet for his time and insight Dome Canada Limited, Marshall Minerals Corporation and on a number of property tours in and around the map area.

5 6 NORTHERN SWAYZE GREENSTONE BELT

Jackson et al. (1994) define supracrustal assemblages ARCHEAN as regional map units that contain rocks sharing some, but not all, of the following properties: lithic attributes, geochemistry, facies association, geophysical signature, Ultramafic Metavolcanic Rocks structural style and age. The units contained within an assemblage need not be stratigraphically related, and an Previous mapping in the synoptic area took place prior to assemblage may either be in fault or depositional contact the general recognition of the existence of ultramafic with other assemblages. extrusive rocks and thus all ultramafic rocks were classi- fied as intrusions (e.g., Prest 1951; Milne 1972; Breaks The MRA is confined to the northern part of the belt 1978). However, current mapping has shown many of and is composed of tholeiitic mafic volcanic rocks with these ultramafic units to be of extrusive origin. The close lesser components of komatiitic ultramafic volcanic rocks, spatial relationship of the komatiite flows (unit 1, Map calc-alkalic intermediate and felsic volcanic units, and 2627, back pocket) with massive, medium-grained cumu- clastic and chemical sedimentary units. The HWA extends late-textured serpentinite bodies of more enigmatic origin south of the synoptic area into the central part of the (unit 7, Map 2627, back pocket) suggests a cogenetic rela- Swayze greenstone belt. It consists predominantly of tionship which is not as yet fully understood. tholeiitic mafic volcanic rocks, with minor intercalations of fine-grained clastic and chemical sedimentary rocks, Komatiitic ultramafic flows (unit 1, Map 2627, back calc-alkalic felsic pyroclastic rocks and komatiitic ultra- pocket) represent an estimated 5% of the MRA, 1% of the mafic flows. The HNA is confined to the southeastern part HWA and were not observed within the HNA. A number of the NSGB and consists predominantly of calc-alkalic of these units in the MRA are laterally extensive. The most intermediate and felsic volcanic rocks that have been extensive unit occurs in Penhorwood and eastern Keith intruded by extensive ultramafic and gabbroic sills. A lat- townships, with dimensions of about 15 km (length) by up erally extensive, but relatively thin, unit of iron formation to 1 km (width). In central Keith Township, a number of caps the HNA and delineates much of the boundary lenticular units 1 to 2 km long appear to lie along the same between the HNA and the MRA. stratigraphic horizon, suggesting the lenticular morphology might represent basinal areas of komatiite accumulation Table 1 is a presentation of the main rock units within the separated by areas of higher paleorelief without komatiite synoptic area. These units are discussed in more detail below. deposition. This observation is supported by the common

Table 1. Lithologic units for the northern Swayze greenstone belt.

PHANEROZOIC Metamorphosed Ultramafic Cumulate Rocks CENOZOIC Dunite, peridotite, pyroxenite QUATERNARY PLEISTOCENE AND RECENT Chemical Metasedimentary Rocks Glacial, glaciofluvial, lacustrine and fluvial Magnetite iron formation, siderite iron formation, sulphide deposits iron formation, graphitic mudstone, chert Unconformity Clastic Metasedimentary Rocks PRECAMBRIAN Sandstone, siltstone, mudstone, conglomerate, tuffaceous PROTEROZOIC wacke, paragneiss Mafic Intrusive Rocks Diabase dikes Felsic Metavolcanic Rocks Tuff, lapilli tuff, tuff breccia, massive flow, brecciated flow ARCHEAN Alkalic Mafic Intrusive Rocks Lamprophyre dikes Intermediate Metavolcanic Rocks Tuff, lapilli tuff, tuff breccia, pillowed flow, massive flow, Late Felsic to Mafic Plutonic Intrusive Rocks amygdaloidal flow, brecciated flow Granodiorite, quartz monzodiorite, granite, tonalite, quartz diorite, gabbro, clinopyroxenite, pegmatite, porphyry, felsite Mafic Metavolcanic Rocks Massive flow, pillowed flow, variolitic flow, amygdaloidal Early Felsic to Mafic Plutonic Intrusive Rocks flow, brecciated flow, plagioclase-phyric flow, pyroxene- Tonalite, quartz diorite, granodiorite, quartz monzodiorite, spinifex-textured flow, tuff, lapilli tuff, tuff breccia granite, diorite, gabbro, porphyry, felsite

Metamorphosed Mafic Intrusive Rocks Ultramafic Metavolcanic Rocks Gabbro, melagabbro, leucogabbro, diorite, anorthosite, Massive flow, spinifex-textured flow, polyhedral-jointed anorthositic gabbro flow, brecciated flow

7 OGS REPORT 297 association of the komatiitic flows with sulphidic iron for- consists of angular to subrounded clasts of spinifex-tex- mation and fine turbidites, which implies relatively deep- tured komatiite, and amygdaloidal mafic and intermediate water deposition. volcanic rocks. Clast types vary within the unit from dominantly intermediate flow clasts to dominantly ultramafic The extrusive origin of these ultramafic rocks is flow clasts. Brecciated clasts are supported in a sparse indicated by features such as spinifex textures. In some matrix of finely comminuted material largely derived from well-preserved areas, flow units and top criteria are deter- the clasts. Locally, thin, spinifex-textured to massive minable based on the classic distribution of uppermost komatiite flows are interbedded with breccia units. This flow-top breccias, fine, random spinifex grading downwards feature indicates the breccia is synvolcanic, rather than into coarse oriented spinifex (A zone) and a lowermost tectonic as was originally suggested by Prest (1951). cumulate unit of equigranular ultramafic rock (B zone; Donaldson 1982). Flow units range from 1 to 10 m thick in the map area. Many of the flows are massive, fine- to Mafic Metavolcanic Rocks medium-grained cumulate-textured units commonly dis- playing well-developed polyhedral jointing, with or without associated spinifex textures. Massive komatiitic flows Mafic volcanic rocks represent about 70% of the MRA, range from equigranular to porphyritic. The rocks typically 90% of the HWA and do not occur within the HNA, with feel talcose when powdered and have a wide variety of the possible exception of mafic units east of the Mindedo weathered surface colours, ranging from green to orange- Creek fault in eastern Kenogaming Township. Amphi- brown. Where highly strained, the ultramafic volcanic bolitic remnants represent about 10% of the Kapuskasing rocks have been altered to chlorite-talc-carbonate schists, Structural Zone and are probably mafic volcanic units with or without a bright green fuchsitic mica. and/or synvolcanic mafic intrusions metamorphosed to granulite facies (Riccio 1981). In komatiites with olivine spinifex, the relict olivine crystals have blade-like morphologies (pseudomorphed by Amphibolites in the Kapuskasing Structural Zone serpentine, chlorite or amphibole) with an interstitial occur as isolated rafts intruded by a variety of granitic groundmass of fine-grained plumose pyroxene (replaced gneisses. These rafts occur both as large mappable units by amphibole and/or chlorite), with or without intergrown and as outcrop-scale inclusions. The mappable units are plagioclase and opaque minerals. The olivine spinifex may commonly surrounded by granitic gneiss with abundant, be randomly oriented and fine grained near the tops of unassimilated amphibolite inclusions. The amphibolites flow units to extremely coarse grained with a preferred are fine- to medium-grained, dark grey to black rocks with orientation roughly perpendicular to the orientation of the strongly foliated to gneissic textures. They are mainly flow units. In the lowermost parts of the flow units composed of hornblende and plagioclase. Accessory minerals (B zone), orthocumulate textures predominate. Cumulus include clinopyroxene, garnet, quartz and opaque minerals. olivine (pseudomorphed by serpentine, chlorite and/or amphibole) occurs as equant, medium-grained euhedral Mafic volcanic rocks in the Swayze greenstone belt crystals with fine-grained intergranular intergrowths of vary from light green, to dark green to black on weathered plumose pyroxene and opaque minerals, very similar in surfaces. They range from soft and chloritic to relatively habit to the interstitial textures within the spinifex parts of hard and amphibolitic. Massive flows are the most common the flow. mafic volcanic rock type and vary from fine to medium grained. Pillowed flows occur in gradational contact with Rare komatiitic flow units consisting of pyroxene the massive flows. Pillows average 30 to 50 cm in length spinifex were observed. A good example of this komatiite with thick selvages (up to 2 to 3 cm) that are darker green type occurs in the ultramafic volcanic unit immediately in colour and more rusty than the pillow interiors. The north of the Radio Hill iron formation, east of the mafic volcanic rocks are predominantly aphyric in hand Groundhog River. In these units, the uppermost part of the specimen. Rare exceptions occur in a few outcrops of flow units (A zone) consists of acicular, skeletal amphi- plagioclase-megaphyric mafic volcanic rocks adjacent to bolitized pyroxenes in an interstitial groundmass of very the Nat River granitoid complex in southeastern Muskego fine-grained amphibolitized pyroxene, plagioclase and Township and northeastern Penhorwood Township. opaque minerals. In the lower part of the flow unit Vesicles infilled with quartz, carbonate and/or epidote are (B zone), an orthocumulate texture is preserved consisting widespread in the pillowed flows. They typically range up of medium-grained, equant, euhedral, skeletal, tremolitized to 2 to 3 mm in diameter and are concentrated in the outer pyroxenes in a goundmass similar to the spinifex part of parts of the pillows. Variolitic flows consist of abundant, the flow unit. light grey, 1 to 5 cm varioles which tend to coalesce in the interior parts of pillows. In thin section, the varioles con- An unusual heterolithic breccia occurs in ultramafic sist of radiating to concentric intergrowths of fine-grained, volcanic rocks located north of the CNR tracks about 1 km acicular, amphibolitized pyroxene with very fine-grained, west of Palomar siding in Keith Township. The breccias intergranular anhedral plagioclase. They have slight protu- are surrounded to the south, west and north by a large area berances on their outer surfaces (visible in thin section), of massive, medium-grained, adcumulate-textured ultra- suggesting an origin as devitrification spherulites rather mafic rocks (unit 7, Map 2627, back pocket). The breccia than immiscible liquids.

8 NORTHERN SWAYZE GREENSTONE BELT

Relict subophitic textures are preserved in some medium- Pillow breccia, autoclastic flow breccia and highly grained massive flows. Massive mafic flows containing vesicular flows are abundant east of the Ivanhoe Lake pyroxene spinifex textures occur locally in northern Keith pluton. This is also an area of extensive hydrothermal Township. Lower cumulate-textured bases (B zone) were silicification that probably occurred as a consequence of not observed in these spinifex-textured basaltic flows. the original porosity of these rocks. Pillow breccias are Rather, the central parts of these flow units exhibit a fine to more abundant than pillowed flows in this area and consist extremely coarse spinifex texture, with crystals oriented of light grey, irregularly shaped, amygdaloidal pillow frag- roughly perpendicular to the flow direction. Textures in the ments in a medium grey, sericitic hyaloclastite matrix. spinifex-textured mafic flows are microscopically similar to the ultramafic pyroxene spinifex-textured flows (described Intermediate fragmental rocks consisting of tuff, lapilli above), except that the content of fine-grained interstitial tuff and tuff breccia are common within the HNA, but rel- plagioclase is sufficiently high (up to 30%) to suggest a atively uncommon within the MRA. Clast populations basaltic composition. Pyroxene spinifex textures also occur within the fragmented units range from monolithic to het- sporadically in the coarser grained massive mafic flows. erolithic. The fragments are composed of various aphyric They consist of actinolitized pyroxene in large, acicular, to porphyritic, nonvesicular to highly vesicular, intermediate dendritic grains in a groundmass of finer grained plagioclase volcanic clasts (possibly pumiceous in texture). These and amphibole. fragmental rocks are light to medium grey-green and relatively hard. Fine- to medium-grained plagioclase crystals Breccias consisting of brecciated pillows or autoclastic (constituting 5 to 30% of the rock) are common and minor flow breccias in massive flows are locally present. Mafic quartz crystals may also be present. Plagioclase, amphibole, pyroclastic rocks consisting of tuff, lapilli tuff and tuff biotite and quartz are essential minerals, while accessory breccia are very rare. These units are largely reported in minerals may include chlorite, sericite, carbonate, epidote diamond-drill core logs and could possibly be misidentified and opaque minerals. With a few exceptions, the fragmental flow breccia. units of the HNA are poorly sorted without any visible bedding or grading. Rare interbeds of finely laminated Mineralogically, the mafic volcanic rocks predominantly siltstone and normal grading occur in the northern margin consist of amphibole and plagioclase. Throughout much of of the HNA. Massive to laminated, amygdaloidal interme- the area, the mineral assemblage of actinolite and albite, with diate flows and flow breccias were also observed in a or without accessory epidote, sericite, carbonate, quartz, number of localities within the HNA. chlorite, leucoxene and opaque minerals, indicates they are of mid- to upper-greenschist metamorphic facies. Locally, the presence of garnet, biotite, hornblende and plagioclase of Felsic Metavolcanic Rocks oligoclase to andesine composition indicate the mafic volcanic rocks were recrystallized to amphibolite metamor- Felsic volcanic rocks constitute about 5% of the MRA in a phic facies within 1 to 2 km of the contacts with the large number of isolated lenticular units scattered throughout granitoid bodies, and throughout much of southern Ivanhoe the assemblage. Minor felsic units also occur in the HWA Township. and HNA.

The felsic volcanic units are light grey on weathered Intermediate Metavolcanic Rocks surfaces and are typically quartz- and/or feldspar- phyric. Felsic volcanic rocks are massive to fragmented. Intermediate volcanic rocks constitute about 10% of the Pyroclastic units are subdivided into tuff, lapilli tuff and MRA with much of these occurring in the northwestern part tuff breccia. Felsic flows are exposed in a small outcrop on of the assemblage. They represent about 5% of the HWAand the southeast side of Highway 101. They are massive and 75% of the HNA. generally nondescript, but locally contain zones of angular flow breccia and isolated miarolitic cavities infilled by The intermediate volcanic rocks are medium to light very fine-grained quartz. Felsic volcanic rocks commonly green-grey on weathered surfaces. In the northwestern part contain up to 25% plagioclase and quartz phenocrysts in a of the MRA, the majority of the intermediate volcanic rocks very fine-grained groundmass of recrystallized quartz, are flows which are typically plagioclase-phyric and amyg- feldspar, sericite, biotite, chlorite, carbonate and epidote. daloidal. Pillowed flows have thin dark grey to dark green pillow selvages. Amygdules may constitute up to 20% of the Some of the felsic units appear to be complexes of rock and range up to several centimetres in diameter. They intrusive and extrusive origin, possibly in an exogenous are typically infilled with carbonate, quartz, epidote, biotite dome-like setting. The Groundhog Lake felsic complex is and/or chlorite. Plagioclase and rarely pyroxene (replaced by a large enclave (3 by 5 km) within the Kukatush pluton. amphibole) phenocrysts may constitute up to 20% of the The complex consists, for the most part, of a weakly foli- flows. They occur in a very fine-grained groundmass of ated, homogeneous, porphyritic, very fine-grained, massive recrystallized amphibole, chlorite, epidote, opaque minerals felsic rock. Subordinate felsic to intermediate pyroclastic and/or biotite, commonly with plagioclase microlites either rocks and interbedded wackes occur along the southern in random pilotaxitic or aligned trachytic orientations. margin of the body. The massive felsic rock is typically

9 OGS REPORT 297 composed of 1 to 2% feldspar phenocrysts (1 to 3 mm in Another clastic unit, up to 1 km wide, lies north of the diameter) in a very fine-grained, equigranular groundmass main clastic unit in the southwestern part of Muskego of anhedral quartz and feldspar with 2 to 10% muscovite, Township. It is not well exposed and lies within the Slate biotite, chlorite and epidote. Microscopic examination of a Rock deformation zone. This unit appears to lack con- sample from the south-central part of the complex glomerates and consists of turbiditic sandstone, siltstone revealed that muscovite grains are partially replaced by and mudstones with a considerable intermixture of inter- fibrolitic sillimanite. This feature indicates the complex mediate volcanic rocks. North of Slate Rock Lake, wackes has experienced metamorphism to amphibolite facies. within this northern unit are thickly bedded and normally Irregular patches of coarser-grained granitic material were graded. They consist of feldspathic wacke with a framework locally observed, likely produced by the escape of a related, of mainly plagioclase grains and subordinate quartz volatile-rich phase. Minerals within the coarser phase are grains, in a matrix of finer-grained feldspar and quartz similar, but with a higher proportion of biotite to muscovite with accessory sericite, chlorite, opaque minerals, biotite, (i.e., 8% biotite, 2% muscovite) and about 5 to 10% micro- epidote and zircon. cline. The microcline occurs in subhedral crystals in the groundmass and as rare rapakivi-textured phenocrysts, A third clastic unit lies immediately south of the consisting of microcline cores surrounded by finer, euhedral, Radio Hill iron formation. Its width is somewhat conjec- plagioclase crystal-rich rims. Miarolitic cavities were tural, as there are only a few outcrops of thickly bedded observed within the porphyritic rock along the west shore wacke occurring sporadically immediately south of the of Groundhog Lake. Radio Hill iron formation.

Less extensive clastic sedimentary units are scattered Clastic Metasedimentary Rocks throughout the map area. They consist of thinly to thickly bedded wacke, siltstone, mudstone and minor conglomerate. In general, these units are intimately intermixed with ultra- Clastic sedimentary rocks represent about 10% of the MRA mafic to felsic volcanic units and in some localities with and are a very minor component of the HWA and HNA. chemical sedimentary rocks. The coarser parts of the units A wide variety of sedimentary types are present. Clastic are composed of minor conglomerate and feldspathic and sedimentary rocks of the MRA, consisting of conglomerate, lithic wacke. sandstone, siltstone and mudstone, are poorly exposed in a unit up to 4 km wide that extends across the northwest and Siltstones are light grey to dark grey, and mudstones central part of the map area and terminates against the are dark grey to dark green on weathered surfaces. Both cumulate-textured ultramafic to gabbroic unit hosting the are typically schistose and thinly laminated. Silty layers Reeves and Penhorwood mines. The conglomerate units are composed of very fine-grained recrystallized feldspar, are heterolithic and composed of well-rounded to subangular quartz, chlorite, sericite, carbonate and biotite. Mudstones clasts of felsic porphyry, volcanic clasts of varying com- have a higher proportion of micaceous minerals. position (i.e., ultramafic to felsic) and up to 5% of a fine, Tourmaline porphyroblasts occur in turbidites interbedded sugary-textured quartzose material which could represent with ultramafic to intermediate volcanic rocks northeast of either recrystallized chert or vein quartz. Conglomerate Palomar Lake, in northeastern Keith Township. beds are up to 1 m thick and are typically in contact with interbedded, fine- to medium-grained sandstone beds up to 50 cm thick. Normal grading and interbedded siltstone and mudstone units are locally evident. Chemical Metasedimentary Rocks

Chemical sedimentary rocks, consisting of banded mag- A relatively proximal provenance is suggested for this netite-, sulphide-, graphite-, siderite- and chert-facies iron clastic sedimentary unit. It is most likely that the sediments formation occur scattered throughout the map area in all were derived from local volcanic edifices and deposited by the supracrustal assemblages. Three extensive units of turbidity currents in submarine fans. This is indicated by magnetite iron formation are the Palomar, the Radio Hill the proportion and variety of volcanic clasts, and the and the Nat River iron formations which are described in changes in dominant clast types in different locations. For more detail below. Sulphide iron formation consists of example, conglomerates observed along the Ivanhoe fine-grained, laminated pyrite or beds of concretionary River, in Foleyet Township, contain clasts of spinifex- pyrite nodules interbedded with graphitic mudstones textured ultramafic volcanic rocks and massive sulphides and/or chert. These sulphide iron formations and graphitic where the sedimentary unit overlies a thick ultramafic mudstones occur in units with fine-grained wacke and volcanic unit in the vicinity of a number of known massive- siltstone and are interbedded with mafic and ultramafic sulphide lenses (Ayer 1993). In contrast, the conglomerates volcanic rocks in a number of localities throughout the and wackes south of Slate Rock Lake, in Keith Township, map area, many of which have been identified by geo- contain relatively abundant quartz-phyric felsic clasts and physical surveys and diamond drilling. The sulphides are pre- quartz sand immediately east of a 500 m thick unit of dominantly pyrite and/ or pyrrhotite and may also include quartz-phyric felsic volcanic rocks. sphalerite and chalcopyrite (see “Economic Geology”).

10 NORTHERN SWAYZE GREENSTONE BELT

A banded magnetite-chert iron formation unit, termed feature suggests a facies change to sulphide and/or the Palomar iron formation (Ayer, in press), occurs north graphite facies. Sporadic lenses of magnetite-facies also of the MacKeith fault in Keith Township. The iron forma- occur further to the east at the HNA-MRA contact, south- tion is about 10 km long and up to several hundred metres west and south of Crawford Lake. The iron formation does thick. The unit consists of a number of separate iron not appear to continue east of Crawford Lake. formation units up to 12 m thick, interbedded with massive and pillowed mafic flows. Magnetite-rich beds of fine-grained euhedral magnetite intergrown with anhedral Metamorphosed Ultramafic quartz are up to several centimetres thick. Chert beds of similar thickness consist of recrystallized anhedral to Cumulate Rocks granular quartz and commonly contain radiating sprays of prismatic tremolite porphyroblasts. Locally, a distinctive Cumulate-textured ultramafic bodies represent about 20% blue magnetite-chert banded iron formation was intersected of the HNA and 2% of the MRA. The units are up to 15 in diamond-drill core. This unit is distinguished by the km in length and 500 m in width. The interpreted setting presence of porphyroblasts of a blue amphibole of possible of these rocks is somewhat enigmatic and the unit may be sodic composition (riebeckite?). composed of both flows and sills. The rocks of this unit were originally mapped as intrusions (Prest 1951; Milne The Radio Hill iron formation has a strike length of 1972). Many of these massive cumulate-textured units about 10 km with a maximum thickness of 500 m in the within the MRA grade laterally, and rarely vertically, into vicinity of Radio Hill, in Penhorwood Township. spinifex-textured komatiitic flows. Recent research on Throughout much of its length it is overlain by komatiite rocks with similar textures and chemistry in other Archean flows to the north and underlain by thickly bedded wacke. terranes has indicated that some of these cumulate-textured Milne (1972) indicates 2 seams of iron formation separated ultramafic rocks are a proximal facies of komatiitic flows by felsic volcanic rocks on the western margin of (Hill et al. 1990). Others, such as the numerous ultramafic Penhorwood Township. Only the southern seam appears to cumulate bodies within the HNA, may be sills. These units continue westward into Keith Township. East of Lead- do not grade into spinifex-textured komatiites and may be beater Lake in Penhorwood Township, the 2 units coalesce subvolcanic intrusions related to the same magmatic events which resulted in the komatiite flows found in the and thicken (probably in an isoclinal F1 fold nose) to form a single zone about 200 m thick. East of this, in the MRA. Radio Hill area, the iron formation is folded into an isoclinal S-shaped fold about 500 m thick (F2 folding?), The ultramafic cumulates are fine- to medium-grained plunging north-northwest at about 50¡ (Milne 1972). massive rocks that range in colour from white to dark green on weathered surfaces. They are strongly magnetic and where undeformed, are relatively resistant to weathering. The unit consists of magnetite, siderite, sulphide, silicate Where they have experienced strong ductile deformation, (minnesotaite), hematite (jasper) and graphite iron forma- they are soft, talcose and may contain green fuchsitic tion typically interbedded with chert. A number of distinctive mica. Ubiquitous irregular joints related to serpentinization facies changes occur in the Radio Hill iron formation. In outline polyhedral columns from 10 to 100 cm in diameter. the Radio Hill area in Penhorwood Township, the unit Primary textures are dominantly net-textured adcumulate consists of magnetite, siderite, sulphide, silicate, hematite to mesocumulate and rarely orthocumulate. Forsterite and graphite iron formation. West of the Groundhog River cores within serpentinized rims, surrounded by thin inter- in Keith Township, the magnetite and silicate facies are stitial rinds rich in opaque minerals, have been microscop- absent. Milne (1972) has characterized 4 major vertical ically observed in some of the adcumulates. Rocks with facies transitions in the Radio Hill area. They are, from mesocumulate textures contain serpentinized, anhedral south to north (hanging wall to footwall), 1) sulphide, sil- olivine crystals with a higher proportion of interstitial icate and carbonate facies, 0 to 50 m in thickness; 2) oxide material consisting of talc, serpentine, carbonate and facies with minor carbonate and silicate facies, 30 to 100 m opaque minerals. Preserved orthocumulates, in which in thickness; 3) carbonate and silicate facies, 10 to 80 m in serpentinized cumulate olivine grains are isolated in a thickness; and 4) sulphide facies, 0 to 25 m in thickness. groundmass of intercumulus material, are rare within this The Nat River iron formation caps the HNA and thus unit but are commonly observed in the cumulate portions outlines much of the boundary between the HNA and the of spinifex-textured flows. North of the CNR tracks and MRA in Penhorwood and Kenogaming townships. It west of Palomar siding in Keith Township, rare spherical extends about 20 km and ranges from 30 to 60 m in thick- structures up to 1 cm in diameter are infilled with serpentine ness. The iron formation consists of magnetite, sulphide, and sulphides. These features are suggestive of amygdules silicate and graphite iron formation interbedded with and may be further evidence of an extrusive origin for chert. Magnetite-chert iron formation is the predominant some of the massive, cumulate-textured ultramafic rocks. facies type and its continuous presence is indicated by a strong aeromagnetic response along its margins to about An extensive cumulate-textured body, hosting both the Nat River. East of the Nat River, the magnetic response the Reeves asbestos mine and the Penhorwood talc mine, is attenuated along the south margin, but a response con- occurs in northern Penhorwood and southern Reeves tinues to the east on airborne geophysical surveys. This townships. The unit has a northerly trend which is distinctly

11 OGS REPORT 297 variant from the overall easterly trend of most rock units In the Reeves unit there is a gradational contact between in the NSGB. The northern part of the unit is folded about an underlying ultramafic unit and the overlying gabbro, a northerly trending F2 antiformal syncline. Exposure is indicating the gabbros are differentiates. Differentiation best in the northwestern part of the unit in the vicinity of was also observed in the serpentinite unit overlying the the Reeves Mine, where based on the differentiation trends Nat River iron formation in northern Kenogaming (see “Geochemistry”), the ultramafic body faces to the east. Township. The unit is about 250 m thick at the eastern end, It is underlain by poorly exposed komatiitic volcanic rocks where it appears to consist of several units grading on the west and mafic volcanic rocks to the north. The upwards from olivine orthocumulates into garbbroic zones komatiite unit is up to about 150 m wide. The basal portion and spinifex-textured pyroxenites. Locally, the gabbroic consists of talc-carbonate schists in highly strained contact portion of these differentiated bodies have random with schistose clastic sedimentary rocks to the west. The spinifex textures consisting of elongate branching pyrox- schists are succeeded to the east by spinifex-textured enes in a groundmass of fine-grained plagioclase. These flows grading into brecciated flows. The komatiite unit is textures are similar to the gabbroic central zones of large overlain by a thick unit of massive, serpentinized adcumu- differentiated komatiite flows such as the Boston Creek late dunite capped by about 3 m of pyroxenite grading into flow in the Kirkland Lake area of the Abitibi greenstone a thick gabbroic unit in the core of the antiformal syncline. belt (Stone et al. 1987).

Mafic intrusions include dark green, medium- to Metamorphosed Mafic coarse-grained gabbro and minor melagabbro. Light grey- Intrusive Rocks green, medium- to coarse-grained leucogabbro may form isolated bodies, such as the lenticular intrusion west of The most extensive mafic intrusion within the map area is Muskego Lake in northeastern Ivanhoe Township, or the Shawmere anorthosite. It is located in the northwestern occur more commonly as minor differentiates closely portion of the map area within the Kapuskasing Structural associated with gabbroic to ultramafic bodies. Inequi- Zone. Within the NSGB, less extensive mafic intrusive granular textures composed of randomly oriented, acicular, rocks represent about 5% of the HWA and HNA, and less amphibolitized pyroxenes in a finer plagioclase-rich than 1% of the MRA. Some of these are intrusive units, as groundmass are common. Relict subophitic textures were indicated on previous maps (Prest 1951; Milne 1972; also observed in thin section. Breaks 1978). Others, however, may be extrusive in origin, representing large ponded and locally differentiated flows. The elliptical Cornice Creek gabbro occurs in the southwestern part of Keith Township. The intrusion is well The Shawmere anorthosite complex is a deformed foliated along its margin, and locally contains felsic to and metamorphosed Archean basement-type anorthosite mafic volcanic xenoliths. The rock is characterized by within the Kapuskasing Structural Zone. It underlies the large clusters (5 to 10 mm) of hornblende crystals set in a western part of Foleyet Township in a northeast-trending finer grained matrix dominated by plagioclase. Such texture complex about 50 by 10 km in size (Thurston et al. 1977). is typical of many other gabbroic bodies in Keith Riccio (1981) subdivided the intrusion into a main zone Township. Microscopically, the rock displays a subophitic and a marginal zone. In the map area, the main zone con- texture with coarse-grained, subhedral, amphibolitized sists largely of leucogabbro and anorthosite, with smaller pyroxene crystals that partially to totally enclose subhedral amounts of gabbro, melagabbro and ultramafic rocks. The to euhedral plagioclase crystals. marginal zone consists of foliated, garnetiferous amphibolite cut by anorthosite and gabbro dikes. The gabbroic rocks typically consist of plagioclase megacrysts in a fine- to medium-grained recrystallized matrix of plagioclase, Felsic to Mafic Plutonic Rocks amphibole and pyroxene with or without minor opaque minerals, quartz and garnet. Anorthositic rocks consist of The relative age of the plutonic rock units indicated on a medium-grained granulated mosaic of plagioclase and Map 2627 (back pocket) is based on the absence or presence only rarely contain plagioclase megacrysts. Mafic minerals of a tectonic fabric and its intensity of development, as consist largely of hornblende, but may also include garnet, there are only a few precise U-Pb zircon age determinations titanite, epidote, chlorite and biotite. Gneissic textures pre- on the plutonic bodies within the area. The reader is dominate in the margins and clotty and coronitic textures advised that these criteria should only be considered as in the central parts. guidelines to relative age. Previous U-Pb age determinations (Percival and Krogh 1983; Frarey and Krogh 1986) suggest The compositional and textural similarity of the mafic that the plutonic rocks of the Kapuskasing Structural Zone intrusions in the Swayze belt with the volcanic rocks (KSZ), with a minimum crystallization age of 2765 Ma, strongly suggests that they are synvolcanic and that some are generally older than those of the NSGB. Initial results may be thick massive flows that cooled slowly. However, of an ongoing U-Pb geochronological study focussed on locally crosscutting contacts indicate that at least some of the Swayze greenstone belt (SGB) and surrounding grani- these are intrusions. Some of the gabbro bodies are closely toids also suggest younger ages for the plutonic suites of associated with the cumulate-textured ultramafic units. the SGB, but also show a wider range of ages than was

12 NORTHERN SWAYZE GREENSTONE BELT previously recognized. For example, results of the study NAT RIVER GRANITOID COMPLEX indicate an age of 2740 Ma for the Chester biotite trond- hjemite pluton in the southeastern part of the SGB The Nat River granitoid complex marks the northern (Heather and van Breemen 1994). In addition, the study boundary of the north Swayze greenstone belt and extends reveals that the Kenogamissi batholith is composed of from the Ivanhoe Lake cataclastic zone eastward across phases with a wide range of ages, from 2713 to 2665 Ma. the map area. The distribution of this complex is largely based on the interpretation of aeromagnetic patterns. This The more extensive granitic complexes and plutons interpretation, supported by sparse outcrop, also indicates that the early felsic to intermediate intrusions have lower are described below. Smaller intrusions consist of early to and less variable magnetic susceptibilities. The complex late granitic stocks and dikes within the supracrustal rocks consists of 1) both early, strongly foliated to gneissic, of the NSGB and are not described in any detail. Early hornblende-biotite tonalite to granodiorite and late, mas- foliated porphyritic dikes and intrusions are found sive to weakly foliated, biotite granodiorite; 2) weakly throughout the map area, but they are most abundant in the foliated pegmatite and aplite dikes; and 3) massive granite predominantly sedimentary rocks of northern Keith and dikes. northwestern Penhorwood townships. The intrusions are predominantly of plagioclase porphyry with subordinate Early phases are predominantly strongly foliated to amounts of plagioclase-quartz porphyry. Plagioclase por- gneissic tonalites and granodiorite. The tonalite is light phyry consists of medium- to coarse-grained, oscillatory- grey on weathered surfaces and consists of plagioclase zoned, euhedral plagioclase phenocrysts in a very fine- (oligoclase), quartz and biotite, with accessory epidote and grained groundmass of anhedral-granoblastic quartz and titanite. In eastern and western Muskego Township, the feldspar, with lepidoblastic biotite or chlorite (after dominant rock type is medium-grained, moderately to biotite?) and minor amounts of epidote, carbonate and weakly foliated pink-weathering hornblende-biotite gran- opaque minerals. The plagioclase phenocrysts have been odiorite and biotite granodiorite. These early intrusive moderately altered to sericite, epidote and/or carbonate. phases are cut by diorite, felsite and pegmatite, and locally contain minor inclusions of tonalite and diorite. Typically the hornblende-biotite granodiorite consists of 35 to 40% KAPUSKASING STRUCTURAL plagioclase (moderately altered to sericite and epidote), 20 to 25% quartz, 10 to 20% microcline, 15 to 20% horn- ZONE (KSZ) blende, 1 to 5% chloritized biotite and trace amounts of titanite, opaque minerals, epidote and zircon. Biotite granodiorite consists of 60 to 70% plagioclase, 20% quartz, Located west of the Ivanhoe Lake cataclastic zone, the 10% biotite and 5% alkali feldspar. The minor hornblende granitoid gneisses of the KSZ are compositionally vari- diorite probably represents a more primitive intrusive able, consisting mainly of tonalite and granodiorite. A phase, closely associated with the granodiorite in south- tonalite gneiss body within the Shawmere anorthosite western Muskego Township. Hornblende diorite consists complex on the western margin of Foleyet Township may of 40 to 60% plagioclase (moderately to strongly altered to be coeval with or intrudes the Shawmere anorthosite. The sericite and epidote), 20 to 40% hornblende, less than tonalite gneiss has a minimum Pb-Pb age of 2765 Ma, thus 5% biotite, less than 5% quartz, less than 5% opaque min- providing a lower limit for the age of the complex and the erals and less than 5% epidote. associated paragneisses and amphibolites of the KSZ (Percival and Krogh 1983). Compositions of the late granitic intrusions within the Nat River granitoid complex are generally more potassic In general, tonalite and diorite gneiss occurs adjacent than the early foliated to gneissic granitoids. They are pre- to, and within, the Shawmere anorthosite complex, whereas dominantly granite and granodiorite, with or without coarse- granodiorite intermixed with tonalite gneiss is concentrated grained, tabular alkali-feldspar phenocrysts. A large late felsic pluton intrudes the foliated granodiorite and diorite further east in the KSZ. The tonalite gneiss commonly within the Nat River granitoid complex in Muskego contains abundant amphibolite xenoliths. Minor quartz- Township and northeastern Foleyet Township. It consists saturated phases consisting of diorite and monzonite of a massive to weakly foliated, equigranular to porphyritic, gneiss occur adjacent to the Shawmere anorthosite com- medium-grained biotite granite and granodiorite with or plex in southwestern Foleyet Township. Tonalite gneiss is without muscovite. Compositionally, these late-stage light grey and contains plagioclase (andesine), quartz, granitic intrusions are distinguished from the surrounding biotite, with or without hornblende and accessory alkali early granitoids by their higher potassium content, signif- feldspar, apatite, epidote and opaque minerals. Granodiorite icant differences in mafic mineral composition and common gneiss is a light pinkish grey with 5 to 15% alkali feldspar porphyritic nature. Typically they consist of 35 to 40% and biotite as the main mafic mineral. Diorite gneiss is microcline, 30 to 35% quartz, 15 to 25% plagioclase, 5% dark grey with plagioclase (andesine), quartz, hornblende, biotite, less than 2% muscovite, less than 2% titanite and with or without biotite, and accessory alkali feldspar, trace amounts of epidote, apatite and opaque minerals. apatite, epidote and opaque minerals. Porphyritic granite is common south of Beatty Lake, where

13 OGS REPORT 297 it contains 5 to 10%, zoned alkali-feldspar phenocrysts 1 to southern and eastern parts of Kenogaming Township and 5 cm in size. Large inclusions of massive, coarse-grained, the southeastern part of Reeves Township. It is a large, alkalic melagabbro occur within the granite on the south- elliptical granitoid complex that separates the Swayze west side of Beatty Lake. The melagabbro consists of 60 greenstone belt from the Abitibi greenstone belt. Recon- to 70% hornblende, 15 to 20% plagioclase (moderately naissance mapping by Heather (1993) has documented a altered to sericite and epidote), 10 to 15% microcline, 2 to complex sequence of at least 6 intrusive phases which range 3% titanite and trace amounts of apatite and opaque miner- from early foliated to late massive granitic phases. als. The alkalic gabbro probably represents a composition- Geochronological studies by Heather and van Breemen ally primitive early phase of the granitic magma. (1994) have revealed a large range of ages, including 1) foliated hornblende tonalites at 2713 Ma; 2) foliated biotite tonalite to granodiorite at 2697 Ma; 3) massive to foliated, Foliated, medium-grained hornblende gabbro with potassium-feldspar megacrystic, hornblende granodiorite at accessory magnetite is seen in outcrop along the 2692 Ma; and, 4) massive biotite granite at 2665 Ma. Groundhog River north of Highway 101. Granitic inclusions and crosscutting aplite dikes suggest the gabbro is an early Only marginal phases were observed in the present intrusive phase of the complex. Airborne magnetic survey study. These range from biotite tonalite in the southwest to data indicate the gabbro is about 2 km wide along the hornblende-biotite tonalite and biotite granodiorite in the southern margin of the complex. Another unit of perhaps southeast. These southern marginal phases are strongly foli- similar chronology occurs along the southern margin of ated, with northerly dips becoming progressively steeper the Nat River granitoid complex in western Reeves and towards the east. A septum of foliated hornblende monzodi- Sewell townships. This unit was not observed in the syn- orite, crosscut by biotite tonalite and aplite dikes, joins the optic mapping and thus has been compiled from Milne batholith with the Nat River granitoid complex in south- (1972). He describes the unit as a mixture of biotite-horn- central Sewell Township. Moderately foliated biotite granite blende granodiorite and diorite. The diorite is composed of occurs in the batholith south of a large supracrustal inclusion 30 to 40% hornblende with coarse-grained plagioclase and in southeastern Sewell Township. interstitial quartz, with accessory titanite, magnetite and apatite, and secondary epidote, chlorite, carbonate, sericite and pyrite. Because the exposure is very poor in this part A late granite phase is indicated within the of the map area, the unit has been largely interpreted from Kenogamissi batholith south of Montgomery Lake, in aeromagnetic maps, as it has a markedly higher magnetic southeastern Penhorwood and southwestern Kenogaming response than the surrounding foliated tonalite and gran- townships. Milne (1972) indicated this phase is continuous odiorite. with a septum of granitic rocks joining the batholith with the Kukatush pluton. High resolution aeromagnetic maps indicate that this granitic septum is more likely a series of sep- In northeastern Foleyet and northwestern Muskego arate intrusions, as is indicated on Map 2627 (back pocket), townships, the Nat River granitoid complex consists of that are most likely satellite bodies or apophyses of the tonalitic gneiss, paragneiss and amphibolite intruded by batholith. Milne (1972) described the granite (or rather biotite-muscovite granite and pegmatite. The granite con- quartz monzonite in Milne’s classification scheme) as being sists of plagioclase (oligoclase), microcline, quartz, biotite massive and inequigranular with coarse-grained plagioclase and muscovite, with trace amounts of epidote, titanite, in a medium-to fine-grained groundmass. The mineralogy is opaque minerals and rarely garnet, which is suggestive of described as mainly oscillatory-zoned oligoclase, micro- an aluminous “S type” granite. The pegmatite dikes con- cline and quartz, with minor biotite and muscovite, acces- sist of graphic-textured intergrowths of perthite and sory titanite, magnetite and apatite, and secondary sericite quartz, biotite, muscovite, and may also contain minor and epidote. fine-grained garnet. Locally, plagioclase within the granite in the northwestern part of Muskego Township has undergone significant epidotization suggesting propylitic alter- TOM SMITH LAKE GRANITIC COMPLEX ation, perhaps as a result of the intrusion of abundant granitic pegmatite dikes in the area. Similar dikes cut foli- A complex of early foliated tonalite and granodiorite, late ated granodiorite along Highway 101 in west-central foliated monzonite and diorite and massive granite and Muskego Township. In this locality, however, the peg- granodiorite, located east of the Ivanhoe Lake cataclastic zone matite dikes also contain minor quantities of chalcopyrite in western Ivanhoe Township, is herein identified as the and molybdenite, which are also suggestive of porphyry- Tom Smith Lake granitic complex. Compositions are highly type mineralization. variable and mainly include tonalite, granodiorite, granite and quartz-saturated, alkalic intrusions. Foliated tonalite is light grey and consists of plagioclase (oligoclase), quartz and KENOGAMISSI BATHOLITH biotite with minor alkali feldspar, titanite, apatite and epidote. Foliated granodiorite typically contains up to 10% coarse- grained alkali-feldspar phenocrysts in a finer grained ground- Within the synoptic area, the Kenogamissi batholith mass of plagioclase (oligoclase), microcline, quartz and occurs in the southern part of Penhorwood Township, the biotite, with minor myrmekite, titanite and opaque minerals.

14 NORTHERN SWAYZE GREENSTONE BELT

Late monzonite, syenite and diorite, with gabbro and western Penhorwood townships. It is a homogeneous clinopyroxenite xenoliths, occur in 2 separate bodies: 1) intrusion consisting of a massive, equigranular, medium- along the Ivanhoe Lake cataclastic zone in southwestern grained hornblende monzonite. In contrast to the low Foleyet Township; and 2) south of the broad part of magnetic susceptibilities of the Hoodoo Lake pluton and Ivanhoe Lake in west-central Ivanhoe Township. the Groundhog Lake felsic complex, the Kukatush pluton exhibits a positive aeromagnetic anomaly which, in con- The phases along the Ivanhoe Lake cataclastic zone junction with limited exposure, indicates a more extensive have a strongly developed cataclastic fabric defined by distribution to the west into Hoodoo Lake than indicated elongate alkali-feldspar augen. Intrusive phases along on previous maps (Thurston et al. 1977; Breaks 1978). The Ivanhoe Lake contain medium-grained alkali-feldspar high-resolution aeromagnetic maps also suggest modifica- phenocrysts and are only moderately to weakly foliated. tion of the interpreted contacts of Milne (1972) in south- Percival (1981) interpreted the alkalic intrusions in these 2 western Penhorwood Township. areas as a narrow continuous body. Aeromagnetic data from these areas indicate isolated magnetic highs separated The most abundant phase of the pluton consists of a by magnetic lows. Thus, a more likely interpretation is massive, equigranular, medium-grained hornblende mon- that of 2 isolated alkalic intrusions separated by a large zonite. As seen in thin section, monzonite typically consists unexposed area, which is probably underlain by early foli- of 40 to 50% plagioclase (slightly altered to sericite and ated tonalite and/or granodiorite. Geochronological sam- epidote), 20 to 30% microcline, 0 to 5% quartz, 10 to 20% pling of a diorite from south of the broad part of Ivanhoe hornblende, less than 5% biotite (chloritized with epido- +3 Lake indicates a U-Pb age of 2680 -2 Ma (Percival and tized rims), less than 3% magnetite, less than 3% titanite Krogh 1983). and trace amounts of epidote, apatite and zircon. A more differentiated hornblende-biotite quartz monzonite, con- Foliated syenite and monzonite are pinkish-grey, typ- taining 10% alkali-feldspar phenocrysts (1 cm in size) and ically with up to 10% coarse-grained alkali-feldspar augen 10 to 20% quartz, occurs locally as a marginal phase. Both where the rock is strongly deformed. The phenocrysts phases commonly contain a significant proportion of consist of perthitic alkali feldspar surrounded by anhedral, mafic volcanic xenoliths (5 to 10%). Inclusions of fine- recrystallized alkali feldspar and plagioclase in the matrix grained, felsic volcanic rock were also observed in the with clinopyroxene, biotite and accessory apatite and vicinity of the Groundhog Lake felsic complex. opaque minerals. Foliated diorite is dark grey, with medium- grained plagioclase (oligoclase) crystals in a finer ground- A number of small intrusions with northeast elongation, mass of hornblende, quartz and biotite, with accessory located between the Kukatush pluton and the Kenogamissi titanite, opaque minerals, apatite and epidote. batholith, are most likely satellites of the Kenogamissi batholith. These bodies consist of biotite granodiorite, Gabbro and clinopyroxenite occur as inclusions or muscovite granite and quartz-feldspar porphyry. They are large rafts in the monzonite and syenite intrusions. These strongly foliated, dip gently to the northwest, and are in mafic intrusions manifest a tectonic foliation but their sheared contact with the supracrustal rocks on their south- mineralogy indicates a relatively unmetamorphosed eastern margins. This suggests that southeasterly directed nature, in contrast with the mafic and ultramafic intrusive thrusting along the northwestern contact of the Keno- rocks in the supracrustal sequences discussed above. gamissi batholith may have created the structural site of the Gabbros are dark grey to black and contain 50% normally veins hosting the quartz and barite open pit mines in this area. zoned plagioclase (oligoclase), 25% augite, 12% hornblende and 12% biotite and trace amounts of titanite, epidote, carbonate and zircon. Clinopyroxenite is dark grey HOODOO LAKE PLUTON and medium grained, with coarse-grained hornblende phenocrysts. A typical clinopyroxenite consists of 70% augite, The Hoodoo Lake pluton is a 5 by 10 km northeast-trending 20% hornblende and 10% plagioclase, with trace amounts ovoid, in western Keith and eastern Ivanhoe townships. of titanite and apatite. Although exposures are restricted to the southeastern margin, intrusive contacts are well defined by a distinct nega- In the southwest part of Ivanhoe Township, the main tive aeromagnetic anomaly. The surrounding mafic vol- phase of the complex is a homogeneous biotite granite canic rocks are metamorphosed to amphibolite facies, with consisting of microcline, plagioclase (oligoclase), quartz foliations paralleling the intrusive contact and dipping in and biotite with trace amounts of apatite, epidote and towards the centre of the pluton. U-Pb zircon geo- opaque minerals. Numerous pegmatite dikes, consisting of chronology indicates a crystallization age of 2684±3 Ma graphic-textured intergrowths of perthite and quartz, (Frarey and Krogh 1986). It is a massive, homogeneous, intrude the granite. porphyritic biotite granodiorite characterized by large alkali-feldspar phenocrysts (1 to 3 cm in size) set in a medium-grained groundmass. The granodiorite consists of KUKATUSH PLUTON 50 to 60% subhedral, oscillatory-zoned plagioclase (slightly altered to sericite and epidote), 15 to 25% quartz, 10 to 15% The Kukatush pluton is a 5 by 15 km, elongate, east- microcline, less than 5% biotite and minor amounts of trending body, located in southeastern Keith and south- titanite, epidote, apatite, opaque minerals and zircon.

15 OGS REPORT 297

IVANHOE LAKE PLUTON PROTEROZOIC

The Ivanhoe Lake pluton is a triangular intrusion about 8 km Mafic Intrusive Rocks across. The western part is a massive, pinkish-grey weathering, alkali-feldspar porphyritic, biotite granodiorite con- Diabase dikes occur scattered throughout the map area sisting of plagioclase (andesine), quartz, microcline and and are genetically related to 3 Proterozoic magmatic biotite, with trace amounts of opaque minerals, titanite, events: 1) a northwest-trending Matachewan swarm with a epidote, sericite and carbonate. The eastern part of the pluton U-Pb age of 2454±2 Ma; 2) a northeast-trending swarm consists of massive, light grey weathering, alkali-feldspar restricted to the KSZ with an Ar-Ar age of 2043 Ma; and porphyritic, biotite-quartz monzodiorite composed of 3) an east-northeast-trending Abitibi swarm with a U-Pb strongly saussuritized plagioclase, microcline, quartz and age of 1140±2 Ma (Osmani 1991). biotite with trace amounts of titanite and opaque minerals. Abundant, grey weathering, equigranular tonalite dikes A large number of tholeiitic diabase dikes (unit 11, intrude the surrounding country rock on the southeast Map 2627, back pocket) occur throughout the map area, margin of the pluton. but are most abundant in the 4 eastern townships. All dikes of this set have a northwesterly to northerly trend, are slightly to moderately magnetic and are interpreted as Alkalic Mafic Intrusive Rocks members of the Matachewan swarm. They are most readily detected on vertical gradient or second derivative magnetic survey maps and in many places have their location pos- Alkalic mafic intrusions consist of lamprophyre dikes too tulated on the basis of magnetic interpretation. The dikes small to be portrayed on Map 2627 and are therefore not are dark grey to black on weathered surfaces near their fine- included on the map’s legend (back pocket). The dikes are grained contact margins and are brown-weathering, medium- most abundant in the 4 western townships in close prox- grained and diabasic-textured in their central parts. imity to the KSZ. They have a consistent northeasterly Exposed dikes range up to 80 m in width and some are plagio- trend. The suite is interpreted to be Archean, but may also clase-phyric. Thin section examination of a sample of por- include intrusions associated with alkalic magmatism phyritic diabase indicates it consists of 20% bytownite phe- focussed along the KSZ, which occurred over a protracted nocrysts (An80), 2 to 10 mm in size and strongly altered to period in the Proterozoic and Paleozoic eras (Sage 1991). sericite and epidote, in a subophitic groundmass of normally Some of these dikes may be genetically related to a 40 cm zoned labradorite (50%), hypersthene (25%; moderately kimberlitic dike reported in core from diamond drilling by altered to amphibole and chlorite) and opaque minerals (5%). Dome Exploration (Canada) Limited, in Keith Township west of the Horwood Lake road and north of the Kukatush Two large east-northeast-trending olivine diabase pluton. Watson et al. (1978) indicated the dike consists dikes (unit 12, Map 2627, back pocket), found in the mainly of olivine (40%), phlogopite (25%) and carbonate southeastern part of the synoptic area, are part of the minerals (20%), and lesser amounts of spinel, ilmenite, Abitibi swarm. The southern dike is up to 130 m wide and clinopyroxene, serpentine, perovskite and apatite. may extend for a total length of over several hundred km (Milne 1972). The dikes are characterized by very high The dikes range from mafic to ultramafic in composi- magnetic susceptibility and thus their position on Map tion. They are commonly porphyritic and typically contain 2627 (back pocket) is largely based on aeromagnetic inter- biotite. Massive biotite lamprophyre dikes up to 20 cm pretation. The diabase is very susceptible to weathering thick occur in foliated monzonite along the west side of and thus outcrops typically consist of a veneer of largely Ivanhoe Lake and in the massive granite pluton in south- unconsolidated masses of pea-sized sand. The fresh rock is western Ivanhoe Township. The dikes are carbonate-rich, light grey coloured. The central parts of the dikes are very weather recessively and are rusty brown in colour. They coarse grained and subophitic textured, with lathes of consist of fine-grained pyroxene and biotite phenocrysts, labradorite, interstitial titanaugite and accessory olivine, extensively replaced by carbonate, in a very fine-grained biotite, magnetite and apatite. groundmass whose original mineralogy is obscured by extensive carbonate alteration. Phenocrysts (0.5 to 2 cm) Within the Kapuskasing Structural Zone the diabase of clinopyroxene (30%; moderately altered to amphibole) dikes (not shown on Map 2627, back pocket) are up to 10 m and biotite (20%) in a groundmass of fine-grained ortho- wide and trend east to northeast. They are interpreted to be clase (30%), carbonate (15%) and opaque minerals (5%) part of the Kapuskasing swarm of diabase dikes (Percival were identified by thin section examination of a sample 1990). The dikes are tholeiitic quartz diabase. They are from a 30 cm dike cutting granitoids, along Highway 101 fine to medium grained, brown weathering, and have a west of Scorch Creek. A 5 m ultramafic lamprophyre dike subophitic texture. They consist of plagioclase (normally observed in core from a diamond-drill hole on the east side zoned from andesine to oligoclase) and clinopyroxene of Muskego Lake, consists of phenocrysts of enstatite 1 to with minor opaque minerals and quartz. 5 cm in size (40%; partially altered to talc and serpentine) in a groundmass of phlogopite (20%), tremolite (25%), The larger Matachewan diabase dikes have envelopes serpentine (10%) and opaque minerals (5%). of epidote alteration and locally have associated sulphide

16 NORTHERN SWAYZE GREENSTONE BELT mineralization. Milne (1972) indicates 3 such sulphide (Kaszycki 1992). Varved clay and sand deposits are also occurrences in the eastern part of the synoptic area: 1) dis- visible in the banks of the Ivanhoe River. seminated bornite and chalcopyrite in the serpentinite adjacent to the diabase dike cutting the Reeves asbestos Recent swamp and muskeg deposits occur throughout deposit; 2) disseminated chalcopyrite and pyrrhotite asso- the map area. They are extensive in low areas, particularly ciated with the diabase in the iron formation outcrop south in northwestern Keith and southwestern Muskego town- of Crawford Lake, in Kenogaming Township; and 3) scat- ships. Investigations of the economic potential for peat in tered veinlets containing stibnite in mafic volcanic rocks this area indicated a number of sites with potentially com- associated with the diabase dike in southwestern Sewell mercial resources, with a depth averaging between 2 and 3 m Township. (Dendron Resource Surveys Ltd. 1984).

PHANEROZOIC METAMORPHISM

Pleistocene and Recent Mineral assemblages in paragneiss and amphibolite gneiss indicate granulite-facies metamorphic conditions prevailed The map area lies within the Abitibi upland of the James in the Kapuskasing Structural Zone. Geothermometry and Bay region which exhibits moderately rolling relief, with ele- geobarometry by Percival (1990) indicate metamorphic vations averaging between 300 and 400 m (Kaszycki 1992). conditions increase eastward across the KSZ, representing All surface drainage is northward into Hudson Bay via the the exposure of progressively deeper, lower crustal rocks. Groundhog River and its tributaries. The map area is He estimates maximum temperatures in the range of 700 extensively covered by drift and is characterized by a gently to 800¡C and pressures in the 8 to 9 kilobar range in the rolling till plain. easternmost part, adjacent to the Ivanhoe Lake cataclastic zone. A number of esker systems with a southerly trend transect the synoptic map area. Extensive deposits of out- All supracrustal rocks with the NSGB have been sub- wash sand, reworked into rolling hills by eolian processes, jected to greenschist- or amphibolite-facies metamorphic are evident in the central parts of Ivanhoe Township and conditions. Greenschist-facies mineral assemblages are are closely associated with the main esker meandering in evident throughout most of the belt. Mineral assemblages a southerly trend across central Foleyet and Ivanhoe town- indicative of amphibolite facies occur throughout southern ships. This esker represents an extensive esker system with Ivanhoe Township, south of the Muskego River fault. a regional extent of over 75 km (Thurston et al. 1977). The Contact metamorphism of the supracrustal rocks within esker is up to 100 m wide and rises up to 30 m above the 1 km of the external granitoid intrusions and 500 m of the surrounding countryside. Two other significant esker larger internal plutons has also produced amphibolite- systems bisect the map area. One extends from the north- facies mineral assemblages. This metamorphic upgrading western boundary of Reeves Township to the southeastern is most evident as a colour change from dark green to boundary of Keith Township. The esker rises up to about black in mafic volcanic rocks. Typical mineral assem- 20 m above the surrounding country where it parallels the blages in greenschist-facies mafic volcanic rocks include Groundhog River in eastern Keith Township. A third esker albite, actinolite, chlorite and epidote, while amphibolite- trends from the northwestern boundary of Sewell facies rocks contain oligoclase, quartz, hornblende, and Township to the southeastern boundary of Penhorwood epidote with localized development of medium-grained, Township. The esker rises to over 60 m above the sur- feathery hornblende porphyroblasts or equant garnet por- rounding terrain in east-central Penhorwood Township. phyroblasts. Associated subaqueous fan and eolian sand and gravel deposits parallel these esker systems and they have locally Mineral assemblages consisting of biotite, muscovite, been quarried for their aggregate. garnet and andalusite in the pelitic sedimentary rocks south of the Ivanhoe Lake pluton are also indicative of Glacial striae observed throughout the map area indi- lower amphibolite-facies metamorphism. Porphyroblastic cate the main direction of ice flow was to the southwest at growth is locally evident in sedimentary rocks and felsic 190¡ to 200¡. This feature is related to the main direction volcanic rocks. Hornblende porphyroblasts occur in a of ice transport during the Late Wisconsinan between 10 700 mudstone metamorphosed to amphibolite facies in close and 11 500 years BP (Prest 1970). Other, more obscure, proximity to the contact with the Nat River granitoid com- trends of ice movement have also been identified locally plex, in southwestern Muskego Township. Amphibole and within the map area (Kaszycki 1992). The older trending tourmaline porphyroblasts were observed in greenschist- striae may reflect a pre-Wisconsinan glaciation (Bird and facies chert beds and turbidites, respectively, in Keith Coker 1987). Township. Chloritoid porphyroblasts in schistose felsic volcanic rocks indicate that upper greenschist-facies Much of the map area is covered by glacial till up to contact-metamorphic conditions occurred about 1 km south 35 m thick. Laminated silt and clay occurs in topographic of the Nat River granitoid complex in south-central lows in river valleys and along the shore of Horwood Lake Muskego Township. The chloritoid porphyroblasts are

17 OGS REPORT 297

randomly oriented and overprint an S1 and S2 tectonic fab- occurred prior to deformation and was cut by the posttec- ric, within the Slate Rock deformation zone, indicating that tonic Ivanhoe Lake pluton. This and the early porosity the contact metamorphic event came relatively late in the control of the moderate silicification strongly suggests that tectonic history of the area. silicification was synvolcanic.

Contact strain aureoles also appear to have developed Patchy zones of silicification also occur in an outcrop in conjunction with contact metamorphism, as the of quartz- and feldspar-phyric felsic pyroclastic rocks supracrustal rocks surrounding the Hoodoo Lake and southeast of Highway 101, in the main felsic unit in south- Kukatush plutons have a well-developed tectonic foliation eastern Foleyet Township. A felsic flow in the same unit which parallels the plutonic contacts and dips steeply on the southeast side of the highway also appears to be inwards towards the pluton centres. The latter feature sug- silicified and is cut by abundant quartz veins and cavities gests erosion has removed much of the upper part of the infilled with very fine-grained silica. plutons. Chloritoid-bearing Volcanic Rocks ALTERATION Chloritoid porphyroblasts are found in drill core of car- Mineral assemblages indicative of alteration are evident in bonatized mafic flows associated with a subeconomic a number of localities in the NSGB. Four distinct types are strata-bound sulphide zone and in carbonatized felsic tuffs documented: along the Ivanhoe River, in southeastern Foleyet Township 1) hydrothermal silicification of volcanic rocks (Ayer 1993). An extensive zone of chloritoid alteration, up to about 500 m wide and with an apparent strike length of 2) hydrothermal alteration producing chloritoid-bearing 4 km also occurs in Muskego Township (Ayer, in press). volcanic rocks Fine feathery chloritoid is visible on cleavage surfaces in 3) carbonatization associated with ductile deformation a plagioclase-phyric felsic schist north of Keith Lake. 4) epidotization associated with metamorphism and Along strike with this unit, to both the east and west, hydrothermal alteration medium-grained, black tabular porphyroblasts of chloritoid in felsic carbonatized schists were observed in diamond- drill core. As chloritoid in greenschist-facies metavolcanic rocks has been documented to be the result of hydrothermal Silicification alteration (Lockwood 1986), it is assumed that this zone represents a zone of conformable hydrothermal alteration Hydrothermal silicification was observed in a number of which could be associated with sulphide mineralization. localities in the northwestern part of the MuskegoÐReeves Of economic significance, chloritoid-bearing altered vol- assemblage. The most extensive is a northeast-trending canic rocks are associated with a number of Archean vol- zone of silicification, exposed over an area of 1 by 5 km, canogenic massive-sulphide deposits (Franklin et al. 1975). in northeastern Ivanhoe Township (Ayer 1993). It occurs within intermediate to mafic flows cut by the southeastern margin of the Ivanhoe Lake pluton. Silicification has only occurred to a moderate degree in much of the zone and is Carbonatization most evident in pillow breccia, where the fragments are light grey in a darker grey schistose matrix. Silicification Extensive carbonatization is characteristic of ductile in these zones appears to have been controlled by early deformation zones in the NSGB. The carbonate is com- porosity, as the most intense bleaching is concentrated monly a rusty-weathering iron-magnesium carbonate or around amygdules. This is also supported by the lack of light grey weathering calcium carbonate. The most intense silicification evident in the minor non-amygdaloidal or carbonatization appears to be associated with highly schis- unbrecciated flows occurring within the silicified zone. tose rocks with chlorite and/or sericite, and may occur in Intense silicification is only exposed in the western part of broad zones up to 1 km wide in major shear zones such as the zone. In these areas, the silicification is manifested by the Slate Rock deformation zone. light grey to white rock in which the original volcanic textures have been largely destroyed by multiple generations of fracturing, pervasive silicification and quartz veining. Epidotization

Thin section examination of both types of silicification Rounded, epidote-rich clots occur within amphibolite- indicate a considerably higher proportion of very fine- facies mafic volcanic rocks in south-central Ivanhoe grained quartz, feldspar, sericite and biotite than is evident Township. Epidotization is also evident within and sur- in the unsilicified mafic flows. Numerous dikes of tonalite rounding large diabase dikes. In addition, epidote was cut the silicified zone and foliated silicified inclusions in observed as fine-to coarse-grained euhedral crystals within massive quartz monzodiorite locally occur in intrusive quartz-carbonate veins in ultramafic volcanic rocks cut by breccias near the southeastern margin of the Ivanhoe Lake granodiorite dikes west of the Hoodoo Lake pluton, in pluton. These relationships indicate the silicification Ivanhoe Township. The above types of epidotization are

18 NORTHERN SWAYZE GREENSTONE BELT probably related to remobilization of alkali elements by gone significant epidotization, suggesting propylitic alter- contact metamorphism. ation, perhaps as a result of the intrusion of abundant granitic pegmatite dikes in the area. Pervasive epidotization, possibly related to propylitic hydrothermal alteration, occurs in the foliated granitic Epidotization is also locally evident in ductile defor- rocks along the southwestern side of the open part of mation zones. In the deformation zone on the west side of Ivanhoe Lake. In addition, plagioclase in the granite located Ivanhoe Lake, the evidence suggests it occurred prior to in the northwestern part of Muskego Township has under- carbonatization (Ayer 1993).

19 OGS REPORT 297 Geochemistry

The lithogeochemical features of the synoptic area are FeO + TiO2 based on whole-rock analyses of 136 samples. Sample locations are displayed on Map 2627 (back pocket) and sample descriptions indexed by township and UTM co- PK - Peridotitic komatiite BK - Basaltic komatiite ordinates are provided in Table 2. Tables 3, 4 and 5 present analytical results for samples collected in 1991, 1992 and 1993, respectively. Whole-rock sample analyses were performed by the Geoscience Laboratories of the Ontario Geological Survey, Toronto, for the 1991 samples (Table 3), X-Ray Assay Laboratories, Toronto, for the 1992 samples (Table 4), and the Geoscience Laboratories, Geoservices BK Branch, Sudbury, for the 1993 samples (Table 5). Major oxide contents were determined by X-ray fluorescence (XRF). Loss-on-ignition (LOI) was determined by gravi- metric methods; carbon dioxide and sulphur contents were PK determined by infrared spectrometry. Trace elements were determined by atomic adsorption (AA), X-ray fluores- Al 23 O MgO cence, inductively coupled plasma optical emission spectrometry (ICP-OES), and inductively coupled plasma mass Individual Flow Samples Paired Flow Samples spectrometry (ICP-MS). 93-1014 pyroxene spinifex 91-1010 olivine spinifex 91-119 talc-chlorite schist 91-1215 cumulate base The ultramafic volcanic rocks of the MuskegoÐReeves 92-231 polyhedral joints 92-249 pyroxene spinifex assemblage (MRA) range in MgO contents from 17 to 40%. 92-248 cumulate base They all plot in the komatiitic fields on a Jensen cation 93-1108 olivine spinifex plot (Figure 3), and display a wide range in Mg-Fe-Al 93-1109 cumulate base major oxide variation from peridotitic komatiites (PK) to 93-1114 olivine spinifex basaltic komatiites (BK). A number of paired samples are 93-1115 cumulate base plotted on Figure 3. These represent 2 samples from single flow units: one representing the spinifex-textured rock in Figure 3. Jensen (1976) cation plot of ultramafic volcanic samples. Many the chilled upper part of the flow, and the second from the of the samples are paired, representing a spinifex top and cumulate base lower, cumulate-textured part of the same flow. These from the same flow. paired samples show the cumulate portion to be more primitive than the chilled spinifex-textured part of the flow. In general, the olivine spinifex-textured peridotitic 20 komatiite flows demonstrate a smaller range in Mg-Fe-Al major oxide variation than do the pyroxene spinifex-tex- Basaltic komatiites tured basaltic komatiite flows. Figure 4 displays the chon- 10 drite-normalized rare earth element (REE) values for a number of the PK and BK samples. The figure demonstrates that all the PK samples show distinct light rare earth element (LREE) depletion ([La/Lu]N = 0.5), negative Eu anomalies and flat heavy rare earth element (HREE) patterns at values 2 to 4 times that of chondrite. On Figure Rock/Chondrite 4, sample 93-1108 is from the spinifex-textured top and sample 93-1109 is from the cumulate base of the same Peridotitic komatiites flow. The cumulate sample is more primitive, with lower 1 REE values, but the parallel trend of the REE patterns of Er Pr La Lu Tb Ce Yb Eu Dy Ho Nd Gd Tm these 2 samples demonstrates that there has been negligible Sm REE fractionation between the chilled upper margin of the 93JAA-1108 93JAA-1035 91JAA-0039 flow, which presumably closely resembled the original liquid composition, and the cumulate base. The BK samples are 93JAA-1109 93JAA-1033 93JAA-1014 distinctive from those of the PK, with more fractionated 93JAA-1121 REE values in the 6 to 10 times chondrite range, slightly elevated LREE values ([La/Lu]N = 1.5) and no Eu anomalies. Figure 4. Chondrite-normalized REE plot of ultramafic volcanic samples.

20 NORTHERN SWAYZE GREENSTONE BELT

20 FeO + TiO2 HFT - High-iron tholeiite

HMT - High-magnesium tholeiite 10 CB - Calc-alkalic basalt

Rock/Chondrite HFT

4 Pr Er La Tb Lu Ce Eu Dy Yb Nd Ho Gd Tm CB HMT Sm

Iron tholeiite Magnesium tholeiites 91JAA-1047 91JAA-0008 93JAA-1112 Al 23 O MgO 91JAA-0196 93JAA-1107

Figure 5. Jensen (1976) cation plot of mafic volcanic samples. Figure 6. Chondrite-normalized REE plot of mafic volcanic samples.

Comparison with the geochemistry of komatiites in The overall depleted LREE patterns in the komatiite Newton Township (Cattell and Arndt 1987), in the south- and mafic volcanic samples from the MRA and HWA ern Swayze greenstone belt (SSGB) indicates many simi- suggest derivation from the same source region of depleted larities between the 2 areas. In both areas the olivine Archean mantle. These same LREE-depleted patterns are spinifex-textured komatiites show distinctive LREE evident in the ultramafic and mafic volcanic rocks of depletion, but in the northern Swayze greenstone belt Newton Township in the SSGB (Cattell and Arndt 1987). (NSGB) the REE values range to lower values suggesting A depleted Archean mantle source is also indicated in a more primitive magmas. This is also indicated by higher Sm-Nd isotopic study of the Newton Township ultramafic absolute values of MgO and Ni in the NSGB. In addition, and mafic lavas, with epsilon Nd values of +1.6 to +4.2 in both areas the komatiitic basalts range to moderately (Cattell et al. 1984). These features suggest that the extensive LREE-enriched values. mafic to ultramafic volcanic suites of the NSGB and SSGB developed in a rift environment, with little or no The potential for nickel-copper deposits in the MRA involvement of continental crust, and may be an Archean- komatiites appears to be favourable, as their geochem- equivalent tectonic setting to mid-oceanic ridge or back-arc istry is similar to that of the host rocks of nickel-copper basin volcanism in modern environments. deposits in the Abitibi greenstone belt. Barrie et al. (1993) state that nickel-copper deposits in the Abitibi Subprovince Similarities also exist between mafic volcanic and koma- are hosted exclusively in komatiite flows and hypabyssal tiite REE patterns in the MRA and HWA with those of the sills, represented by chill compositions (i.e., spinifex- KiddÐMunro assemblage. The tholeiitic mafic volcanic textured) with high MgO contents (20 to 35%, anhydrous), rocks in the 2 areas also have similar patterns to modern very low incompatible element contents and LREE- mid-oceanic ridge basalts with depleted LREE values for depleted signatures ([La/Lu]N = 0.5 to 0.8 and Zr/Y less magnesium and iron tholeiites, but with higher absolute than 2.5). In comparison, most barren komatiites have less values for the iron tholeiites (Jackson et al. 1994). primitive compositions, higher absolute values of REE and flat to elevated LREE patterns. Intermediate to felsic volcanic samples from the Hanrahan assemblage (HNA) and MRA plot within the Mafic volcanic rocks from the MRA and Horwood calc-alkalic field on the Jensen cation plot and show ratios assemblage (HWA) dominantly plot in the tholeiitic field which range from calc-alkalic basalts to rhyolites (Figure 7). on a Jensen cation plot (Figure 5). Magnesium tholeiites All display a high degree of LREE fractionation ([La/Lu]N predominate and consist of pillowed and massive flows, = 10), flat to concave-upward HREE patterns, with or including some pyroxene spinifex-textured flows. Iron without slight Eu depletion (Figure 8). What appears to be tholeiites are volumetrically subordinate and consist of lacking, in comparison with Abitibi assemblages such as pillowed and massive flows lacking spinifex. Both iron the KiddÐMunro assemblage, are the tholeiitic felsic dif- and magnesium tholeiites are dominantly LREE depleted ferentiates or rhyolites designated as FIII-type by Lesher ([La/Lu]N = 0.6), with or without slight Eu depletion (Figure et al. (1986). All intermediate to felsic volcanic rocks sam- 6). However, iron tholeiites generally have higher REE pled to date in the NSGB show high degrees of REE frac- values (e.g., sample 91JAA-1047, Figure 6). tionation with highly elevated LREE and depleted HREE

21 OGS REPORT 297

FeO + TiO2 100 CB - Calc-alkalic basalt CA - Calc-alkalic andesite CD - Calc-alkalic dacite CR - Calc-alkalic rhyolite 10 Rock/Chondrite

1 Pr Er La Tb Lu Ce Eu Dy Yb Ho Nd Gd Tm Sm CB CA 93JAA-1062 91JAA-0170 92JAA-1134 CD CR 92JAA-0258 92JAA-0194 93JAA-1071

Al 23 O MgO 91JAA-0184

Figure 7. Jensen (1976) cation plot of intermediate to felsic volcanic Figure 8. Chondrite-normalized REE plot of intermediate to felsic vol- samples. canic samples. patterns typical of calc-alkalic FI-type rhyolites (Lesher et REE values of 0.3 to 0.9 times chondrite. Samples from al.1986). In modern day volcanism these rocks are more the overlying gabbroic part of the body (93JAA-1124, typical of destructive-margin tectonics than the rifting-type 93JAA-1006 and 93JAA-1005) have flat REE patterns at environment suggested by the tholeiitic felsic and interme- values 1 to 10 times chondrite with either Eu enrichment diate volcanic rocks of the KiddÐMunro assemblage or depletion. These patterns indicate that besides olivine (Barrie et al. 1993). and pyroxene, plagioclase must have crystallized on the liquidus at some stage in the magma evolution and was Thus, volcanism in the NSGB can be characterized as concentrated in the gabbroic differentiates. The 3 ultra- having occurred in 2 distinct tectonic environments. The mafic samples all have Eu values below detection limits ultramafic and mafic suites of the HWA and the MRA and thus these rocks would most likely display Eu depletion appear to have been derived from a depleted mantle source anomalies on Figure 10, if their absolute Eu values were with the mafic flows most similar to modern mid-oceanic known. ridge basalts. The intermediate to felsic suites of the HNA and the MRA are clearly calc-alkalic in their affinity and FeO + TiO2 demonstrate a more evolved magmatic source, most similar HFT - High-iron tholeiite to modern island arcs forming at destructive continental HMT- High-magnesium margins. tholeiite BK - Basaltic komatiite Samples from the ultramafic cumulates and associated gabbroic differentiates of the MRA (Figure 9) show a sim- PK - Peridotitic komatiite ilar range to the ultramafic and mafic volcanic samples on the Jensen cation plots (see Figures 3 and 5), and are most probably synvolcanic sills or large ponded flows. Analyses HFT of samples from the Reeves ultramafic to gabbroic body are displayed on Figure 10. Two dunite samples are very BK primitive, with similar REE patterns at 0.2 to 0.4 times chondrite values and slightly fractionated LREE values HMT ([La/Lu]N = 1.5 to 2). Sample 93JAA-1119 is the most primitive and occurs at the base of the unit, while sample PK 93JAA-1118 occurs about 50 m above the base. Sample 93JAA-1122 is a pyroxenite sample which occurs at the Al O MgO top of the ultramafic part of the body, an estimated 100 m 23 above the base of the unit. In contrast to the underlying dunites, the pyroxenite sample displays moderate LREE Figure 9. Jensen (1976) cation plot of ultramafic cumulate and gabbroic depletion ([La/Lu]N = 0.6) but with relatively primitive samples.

22 NORTHERN SWAYZE GREENSTONE BELT

10 10

1 Rock/Chondrite Rock/Chondrite

1 .1 Er Pr La Tb Lu Pr Er Dy Ce Eu Yb Ho Nd La Gd Tb Lu Ce Eu Dy Yb Tm Ho Nd Sm Gd Tm Sm

93JAA-1005 93JAA-1118 93JAA-1122 93JAA-1068 93JAA-1095 93JAA-1097 93JAA-1006 93JAA-1119 93JAA-1124 93JAA-1069 93JAA-1096

Figure 10. Chondrite-normalized REE plot of samples from the Reeves Figure 11. Chondrite-normalized REE plot of samples from the ultramafic ultramafic to gabbroic body. to mafic body hosting the Ireland showing.

Samples collected from the differentiated body host- canic samples from the Joburke Mine plot in the interme- ing the Ireland nickel showing in northeastern Keno- diate to basaltic parts of the iron tholeiite field. This is in gaming Township are shown on Figure 11. Three samples contrast to the patterns of the unaltered mafic volcanic from the northeastern part of the body represent peri- samples collected throughout the NSGB (see Figure 5) in dotite (93JAA-1096), pyroxenite (93JAA-1097) and gab- which only a minor number of the mafic suite samples are bro (93JAA-1095). All 3 samples show similar patterns, iron tholeiites. This iron enrichment is most probably the with significant to moderate LREE depletion ([La/Lu]N = result of hydrothermal alteration and the resultant mobility 0.35 to 0.85). In contrast, peridotite and gabbro samples of iron and magnesium. Similar shifts (not shown) were from the western end of the body (93JAA-1068 and also evident in carbonatized volcanic samples (bearing 93JAA-1069) display flat to slight LREE enrichment pat- chloritoid) from other parts of the synoptic area (i.e., sam- terns ([La/Lu]N = 0.8 to 1.4). This difference may have ples 91JAA-0170, 92JAA-0109, and 92JAA-0221, Tables some economic significance, as the western samples were 3 and 4). collected in the immediate vicinity of known concentrations of nickel, copper and platinum group element (PGE) The intense hydrothermal alteration around the mineralization. It is possible that the samples enriched in Joburke Mine may also be evident in the REE patterns. LREE were contaminated by the assimilation of underlying Figure 13 shows that while the LREE values are in the units enriched in LREE, such as the felsic rocks of the normal range for MRA mafic volcanic rocks, the middle HNA (e.g., see sample 93JAA-1071, Figure 8) and/or the rare earth element (MREE) and HREE values are distinctly Nat River iron formation. This may have provided a mech- depleted, probably as a result of the alteration. Strong anism for sulphur saturation and thus the concentration of depletion in HREE has been documented in carbonatized nickel sulphides in this area (see “Economic Geology”). metabasic schists adjacent to auriferous veins at the Dome Mine in Timmins and has been attributed to leaching by Alteration has had a significant effect on whole-rock carbonate- and potassium-rich hydrothermal fluids geochemical patterns and in particular has affected the (Kerrich and Fryer 1979). In distinct contrast, Schandl and more mobile elements, such as the incompatible elements Gorton (1992) document mobility in the LREE in the iron and magnesium. In sampling for the synoptic project, hydrothermally altered host rocks of Superior Province the effect of alteration was minimized as much as possible massive-sulphide deposits. Hall and Plant (1992b), how- by collecting only samples without evident alteration, and ever, suggest that depletion in HREE values could also be by the removal of weathered surfaces and veining prior to an artifact of the analytical technique if there has been sample submission. Figures 12 and 13 illustrate the effect incomplete digestion of refractory minerals in the ICP of hydrothermal alteration on a suite of highly carbonatized analysis. mafic samples collected in the immediate vicinity of the Joburke Mine, in Keith Township. The altered samples Tectonic environment interpretations are illustrated were provided by Noranda Exploration Company Limited in Figures 14 and 15, in which the mafic volcanic sam- and were analyzed at X-Ray Assay Laboratories, in Toronto. ples collected from the NSGB plot within the field of Locations and results of individual samples are provided ocean floor basalts. If the field of unaltered mafic vol- by Hall and Plant (1992a, 1992b). Figure 12, a Jensen canic rocks on Figure 14 is compared with those of cation plot, illustrates that many of the altered mafic vol- altered mafic volcanic samples from the Joburke Mine

23 FeO + TiO2 HMT - High-magnesium TD - Tholeiitic tholeiite dacite

CB - Calc-alkalic basalt TA - Tholeiitic andesite CA - Calc-alkalic andesite HFT - High-iron tholeiite 10 CD - Calc-alkalic dacite

HFT TA

TD Rock/Chondrite HMT

CA CB CD

1 Al O MgO Er Pr

23 La Tb Lu Ce Eu Dy Yb Ho Nd Gd Tm Sm

Figure 12. Jensen (1976) cation plot of altered mafic volcanic samples Figure 13. Chondrite-normalized REE plot of altered mafic volcanic sam- from the Joburke Mine. ples from the Joburke Mine. Representative samples from analyses provided by Noranda Exploration Company Limited. area (Figure 15), the “blurring” to the left and right of the along a line parallel to the yttrium axis with little devia- ocean floor basalt field in the Joburke samples is most tion towards the zirconium or titanium axes. This con- likely an effect of hydrothermal alteration resulting in firms the above-observed REE mobility, as yttrium is a mobility of the high field strength elements (HFSE), relatively more compatible HFSE and is thus geochemi- which are generally considered to be immobile. In par- cally more similar to the HREE, while zirconium is a rel- ticular, Figure 15 demonstrates that there is considerably atively incompatible HFSE and is thus geochemically more mobility in yttrium as the deviation is focussed more similar to the LREE.

Ti/100 Ti/100 WPB - with plate basalts WPB - with plate basalts OFB - ocean floor basalts OFB - ocean floor basalts LKT - low potassium LKT - low potassium tholeiites tholeiites CAB - calc-alkalic CAB - calc-alkalic basalts basalts

WPB LKT LKT WPB

CAB OFB, LKT, CAB CAB OFB,LKT, CAB

Zr Yx3 Zr Yx3

Figure 14. Pearce and Cann (1973) plot of mafic volcanic samples from Figure 15. Pearce and Cann (1973) plot of the altered mafic volcanic the northern Swayze greenstone belt. samples from the Joburke Mine.

24 NORTHERN SWAYZE GREENSTONE BELT

Table 2. Lithogeochemical sample descriptions, township and UTM co-ordinates. (All UTM values are within Grid Zone 17.)

Sample No. Sample description Township Easting Northing

91JAA-0006 pillowed mafic flow Ivanhoe 390237 5329160 91JAA-0008 pillowed mafic flow Ivanhoe 389725 5329536 91JAA-0009 massive granodiorite Ivanhoe 387492 5338216 91JAA-0039 massive komatiite flow Ivanhoe 384931 5335133 91JAA-0049 foliated tonalite Ivanhoe 380532 5333195 91JAA-0057 massive granodiorite Ivanhoe 381876 5330026 91JAA-0066 massive granite Ivanhoe 381584 5324022 91JAA-0068 pillowed mafic flow Ivanhoe 392902 5332461 91JAA-0073 polyhedral jointed komatiite flow Ivanhoe 394003 5332466 91JAA-0077 polyhedral jointed komatiite flow Ivanhoe 394071 5332272 91JAA-0094 massive quartz monzodiorite Ivanhoe 391294 5335062 91JAA-0102 intermediate amygdaloidal flow Ivanhoe 393075 5335410 91JAA-0105 leucogabbro Ivanhoe 393914 5336075 91JAA-0109 intermediate plagioclase-phyric tuff Ivanhoe 393914 5336075 91JAA-0113 massive mafic flow Ivanhoe 393820 5336406 91JAA-0119 altered schistose ultramafic with chloritoid Foleyet 392034 5339710 91JAA-0124 plagioclase-phyric felsic lapilli tuff Foleyet 392034 5339710 91JAA-0127 massive mafic flow with medium-grained pyroxene needles Ivanhoe 393260 5338193 91JAA-0135 pillowed mafic flow Ivanhoe 395174 5327932 91JAA-0136 pillowed mafic flow Ivanhoe 394195 5325192 91JAA-0137 massive mafic flow Ivanhoe 394195 5325078 91JAA-0139 massive mafic flow Ivanhoe 394836 5325210 91JAA-0149 polyhedral jointed komatiite flow Foleyet 393906 5340575 91JAA-0155 quartz-phyric felsic tuff Foleyet 391888 5340270 91JAA-0161 plagioclase-phyric felsic tuff Ivanhoe 387581 5334572 91JAA-0163 syenite gneiss Foleyet 385555 5339690 91JAA-0168 massive intermediate flow Foleyet 391992 5338863 91JAA-0170 altered quartz-phyric felsic tuff with chloritoid Foleyet 393375 5339814 91JAA-0173 massive mafic flow Foleyet 391345 5342700 91JAA-0176 massive mafic flow Foleyet 390235 5341753 91JAA-0184 quartz-phyric brecciated felsic flow Foleyet 391560 5340715 91JAA-0185 intermediate plagioclase & quartz-phyric tuff Foleyet 392532 5342797 91JAA-0193 massive mafic flow with medium-grained pyroxene needles Foleyet 393498 5338502 91JAA-0196 massive mafic flow with medium-grained pyroxene needles Ivanhoe 391368 5334494 91JAA-0197 silicified amygdaloidal flow Ivanhoe 391746 5334088 91JAA-0198 massive mafic flow Foleyet 391803 5340459 91JAA-1010 spinifex-textured komatiite flow Ivanhoe 390706 5331830 91JAA-1024 polyhedral-jointed komatiite flow Ivanhoe 391380 5333030 91JAA-1047 amphibolitized mafic flow Ivanhoe 388549 5324646 91JAA-1060 gabbro Ivanhoe 391154 5326347 91JAA-1074 gabbro Ivanhoe 390670 5328525 91JAA-1095 mafic flow Ivanhoe 392326 5327271 91JAA-1116 gabbro Ivanhoe 392817 5326524 91JAA-1136 amygdaloidal mafic flow Ivanhoe 395155 5329397 91JAA-1168 tonalite gneiss Foleyet 383389 5340869

25 OGS REPORT 297

Table 2. Continued.

Sample No. Sample description Township Easting Northing

91JAA-1174 granodiorite gneiss Foleyet 384127 5341206 91JAA-1215 polyhedral-jointed komatiite flow Ivanhoe 390706 5331830 91JAA-1218 silicified flow Ivanhoe 391345 5334295 91JAA-2007 paragneiss Foleyet 395738 5348736 92JAA-0018 adcumulate dunite Keith 399128 5334137 92JAA-0045 massive mafic flow Keith 401684 5334388 92JAA-0047 pillowed mafic flow Keith 400588 5333080 92JAA-0066 amygdaloidal pillowed intermediate flow Keith 397575 5337317 92JAA-0109 altered felsic schist with chloritoid Muskego 403836 5338692 92JAA-0141 adcumulate dunite Keith 405170 5335847 92JAA-0142 amygdaloidal intermediate flow Keith 405170 5335847 92JAA-0151 spinifex pyroxenite at base of differentiated flow Keith 406826 5335432 92JAA-0173 massive mafic flow Muskego 406602 5338400 92JAA-0194 quartz- and feldspar-phyric felsic schist Keith 403426 5332611 92JAA-0198 variolitic pillowed mafic flow Keith 406359 5331941 92JAA-0199 massive mafic flow Keith 406359 5331941 92JAA-0221 altered felsic schist with chloritoid Muskego 402615 5338435 92JAA-0229 massive mafic flow Keith 407911 5331965 92JAA-0231 polyhedral-jointed komatiite flow Keith 408401 5332430 92JAA-0237 massive mafic flow Keith 408234 5335800 92JAA-0248 polyhedral base of pyroxene spinifex ultramafic flow Keith 409188 5334010 92JAA-0249 pyroxene spinifex top of komatiite flow Keith 409188 5334010 92JAA-0250 massive mafic flow with medium-grained pyroxene needles Keith 408765 5333780 92JAA-0252 polyhedral komatiite flow with olivine phenocrysts Keith 406549 5335450 92JAA-0253 massive mafic flow Muskego 407247 5339261 92JAA-0258 intermediate lapilli tuff Keith 406906 5335697 92JAA-1017 adcumulate dunite Keith 396859 5336225 92JAA-1030 quartz-phyric felsic flow Keith 397775 5336805 92JAA-1043 massive mafic flow Keith 397922 5335232 92JAA-1052 pyroxene spinifex mafic flow Keith 397882 5334681 92JAA-1053 variolitic pillowed mafic flow Keith 398400 5334590 92JAA-1073 massive mafic flow Muskego 397311 5340702 92JAA-1097 plagioclase megaphyric mafic flow Muskego 409387 5341716 92JAA-1116 massive granite Muskego 404032 5341240 92JAA-1134 plagioclase-phyric felsic porphyry Keith 404845 5328884 92JAA-1143 plagioclase-phyric felsic porphyry Keith 406874 5328984 92JAA-1144 monzonite Keith 407364 5327536 92JAA-1156 polyhedral-jointed komatiite flow Keith 404963 5324471 92JAA-1157 massive mafic flow Keith 404649 5324255 92JAA-1162 felsic schist Keith 402310 5324715 92JAA-1170 massive intermediate flow Keith 403425 5325310 92JAA-1180 granodiorite Keith 400203 5326416 92JAA-1193 quartz-phyric felsic tuff Keith 395718 5326151 93JAA-1001 massive mafic flow Reeves 419426 5339535 93JAA-1005 gabbro Reeves 419622 5338572 93JAA-1006 gabbro Reeves 419800 5337983

26 NORTHERN SWAYZE GREENSTONE BELT

Table 2. Continued.

Sample No. Sample description Township Easting Northing

93JAA-1008 pillowed mafic flow Penhorwood 419952 5337110 93JAA-1014 spinifex-textured komatiite flow Reeves 419114 5339035 93JAA-1016 pillowed mafic flow Penhorwood 420479 5335754 93JAA-1020 polyhedral-jointed komatiite flow Penhorwood 420479 5334444 93JAA-1021 pillowed mafic flow Penhorwood 421478 5336120 93JAA-1027 pillowed intermediate flow Reeves 422227 5338688 93JAA-1033 spinifex-textured komatiite flow Penhorwood 415708 5333601 93JAA-1035 massive komatiite flow Penhorwood 414827 5332014 93JAA-1041 plagioclase porphyry Penhorwood 416389 5336332 93JAA-1042 massive mafic flow Penhorwood 415854 5326847 93JAA-1043 massive orthocumulate ultramafic Penhorwood 413405 5325923 93JAA-1046 spinifex-textured komatiite flow top Penhorwood 412158 5326030 93JAA-1055 quartz- and feldspar-phyric felsic tuff Penhorwood 424430 5331663 93JAA-1059 plagioclase-phyric intermediate flow Penhorwood 423757 5334659 93JAA-1062 plagioclase-phyric intermediate brecciated flow Penhorwood 424071 5334218 93JAA-1068 melagabbro Kenogaming 429624 5335890 93JAA-1069 adcumulate ultramafic Kenogaming 429624 5335890 93JAA-1071 plagioclase-phyric felsic tuff Kenogaming 429613 5336024 93JAA-1078 intermediate flow Kenogaming 430510 5333250 93JAA-1083 intermediate tuff breccia Kenogaming 428146 5331775 93JAA-1085 massive mafic flow Kenogaming 427703 5330244 93JAA-1086 intermediate lapilli tuff Kenogaming 430495 5331525 93JAA-1090 pillowed mafic flow Sewell 424652 5339400 93JAA-1095 gabbro Kenogaming 431667 5337092 93JAA-1096 spinifex-textured ultramafic pyroxenite Kenogaming 431550 5337093 93JAA-1097 orthocumulate ultramafic peridotite Kenogaming 431550 5337093 93JAA-1100 massive mafic flow Reeves 411617 5339041 93JAA-1101 mafic flow Reeves 411582 5339468 93JAA-1102 intermediate Reeves 411828 5338207 93JAA-1104 massive mafic flow Reeves 416118 5340807 93JAA-1106 intermediate flow Reeves 417042 5340935 93JAA-1107 plagioclase-phyric mafic flow Reeves 420238 5341136 93JAA-1108 spinifex-textured komatiite from flow top Penhorwood 418116 5332918 93JAA-1109 polyhedral-jointed komatiite from base of flow Penhorwood 418116 5332918 93JAA-1111 polyhedral-jointed komatiite flow Penhorwood 417639 5333293 93JAA-1112 pillowed mafic flow Penhorwood 416433 5333100 93JAA-1113 massive mafic flow Penhorwood 419749 5333770 93JAA-1114 spinifex-textured komatiite from flow top Penhorwood 419546 5333942 93JAA-1115 polyhedral-jointed komatite from base of flow Penhorwood 419546 5333942 93JAA-1117 massive mafic flow Penhorwood 423328 5335665 93JAA-1118 adcumulate about 50 m above base of ultramafic unit Reeves 419187 5339845 93JAA-1119 adcumulate at base of ultramafic unit Reeves 419079 5338894 93JAA-1121 brecciated komatiite flow Reeves 418878 5338772 93JAA-1122 pyroxenite at top of ultramafic unit Reeves 419895 5338730 93JAA-1124 gabbro at bottom of gabbroic unit Reeves 419895 5338730

27 OGS REPORT 297 LOI Total 5 O 2 OP 2 OK ement values in ppm. 2 MnO MgO CaO Na 3 O 2 Fe 3 O 2 Al 2 TiO 2 Whole-rock geochemical data from Foleyet and Ivanhoe townships. Major element oxide values in weight %, trace rare earth el Method XRF XRF XRF XRF XRF XRF XRF XRF XRF XRF Sample No. SiO 91JAA-000691JAA-0008 51.6691JAA-0009 54.4691JAA-0039 64.86 0.8791JAA-0049 44.99 0.7991JAA-0057 70.47 0.49 15.7891JAA-0066 68.61 0.35 13.9291JAA-0068 72.51 0.17 16.3291JAA-0073 11.07 51.80 0.4091JAA-0077 11.38 6.75 45.31 0.17 16.7591JAA-0094 3.67 0.17 43.76 0.79 15.8991JAA-0102 10.09 0.21 65.41 0.33 14.6591JAA-0105 0.90 0.05 61.59 0.35 14.0691JAA-0109 7.23 2.35 0.19 49.53 0.4691JAA-0113 7.83 6.59 1.32 0.01 57.67 0.5691JAA-0119 11.65 6.84 1.46 8.97 0.03 54.55 0.64 15.5591JAA-0124 22.30 11.39 7.43 0.02 34.97 0.74 16.3691JAA-0127 0.51 11.33 0.18 3.05 72.15 1.30 11.64 3.3291JAA-0135 0.89 3.58 7.17 0.17 48.74 0.31 17.54 3.3991JAA-0136 0.37 5.95 0.18 2.25 57.02 0.27 14.3291JAA-0137 6.37 4.42 0.17 8.72 0.05 1.62 51.27 1.03 0.1491JAA-0139 21.85 6.08 0.10 7.73 0.07 1.21 51.09 1.28 15.6991JAA-0149 23.04 11.50 5.69 9.72 3.21 0.08 0.16 51.46 0.76 13.6491JAA-0155 4.33 0.03 1.59 10.16 8.22 0.06 0.07 46.50 0.83 14.7291JAA-0161 3.98 3.97 1.32 0.14 7.35 1.91 0.86 75.94 0.18 1.17 14.53 2.8491JAA-0163 12.69 8.71 4.44 0.03 0.23 0.17 2.79 73.82 0.40 13.87 0.44 11.13 4.64 4.54 100.18 0.06 5.72 56.87 0.05 0.14 15.87 1.96 0.51 5.00 12.32 0.27 0.23 14.07 5.75 0.13 0.18 99.80 16.60 12.79 6.64 4.21 0.04 0.27 4.40 0.05 0.89 13.26 0.74 12.58 99.67 3.58 0.07 0.97 0.20 5.83 0.07 14.11 1.08 97.79 1.32 8.80 15.41 12.13 0.20 3.38 0.03 17.58 0.51 3.86 99.45 1.54 0.51 0.21 1.36 0.03 1.90 2.81 3.34 6.72 99.77 10.09 0.40 1.64 5.02 0.18 0.13 0.17 6.90 99.33 5.66 7.77 2.83 5.39 0.03 0.11 99.65 5.12 2.99 11.20 0.19 0.05 0.03 1.45 1.02 99.39 0.03 18.34 9.88 0.08 0.18 0.77 98.85 2.97 0.32 7.27 2.22 0.22 4.42 1.66 0.14 98.21 0.70 0.04 9.56 2.31 100.04 1.58 0.26 3.07 2.59 2.98 0.06 99.66 3.72 0.16 11.69 0.11 0.62 0.21 99.65 0.86 0.11 4.82 1.60 98.98 4.26 0.95 0.06 2.92 95.59 1.78 0.16 0.07 0.42 100.14 5.17 0.67 0.86 0.07 99.84 5.21 0.03 1.20 99.81 4.44 1.04 99.55 0.06 4.50 0.05 99.27 0.54 1.04 99.46 1.35 98.65 0.55 99.40 99.49 99.67 Table 3. Table

28 NORTHERN SWAYZE GREENSTONE BELT LOI Total 5 O 2 OP 2 OK 2 MnO MgO CaO Na 3 O 2 Fe 3 O 2 Al 2 TiO 2 Continued. Method XRF XRF XRF XRF XRF XRF XRF XRF XRF XRF Sample No. SiO 91JAA-016891JAA-0170 56.0491JAA-0173 49.9091JAA-0176 0.78 50.8691JAA-0184 0.47 50.3291JAA-0185 16.85 1.64 75.2691JAA-0193 11.48 0.87 63.9991JAA-0196 8.64 13.09 0.14 51.3991JAA-0197 15.02 15.86 0.90 49.4991JAA-0198 17.35 0.12 12.97 1.10 62.7491JAA-1010 12.03 0.41 17.44 0.72 52.0991JAA-1024 0.23 1.21 14.39 4.89 0.52 44.7591JAA-1047 0.36 4.44 1.97 14.85 0.97 51.3591JAA-1060 10.18 0.04 4.36 14.87 0.36 50.2391JAA-1074 4.80 10.42 0.11 5.38 15.34 9.18 0.26 50.9491JAA-1095 0.18 6.39 0.58 6.89 7.38 1.39 50.2391JAA-1116 4.52 0.20 9.70 11.14 1.38 5.35 1.74 0.45 53.0891JAA-1136 0.10 11.07 7.10 13.42 1.39 3.47 50.6091JAA-1168 0.91 1.03 0.22 7.16 13.03 1.27 9.93 0.71 53.96 0.3291JAA-1174 2.62 16.42 0.17 13.42 10.81 4.35 0.56 66.23 0.2891JAA-1215 0.20 0.16 18.29 13.90 13.19 0.22 0.23 6.11 0.85 67.93 0.1191JAA-1218 6.03 16.42 0.24 22.52 11.15 2.26 0.54 38.99 0.1391JAA-2007 5.80 1.77 6.19 10.77 0.26 14.96 10.53 1.40 0.09 17.07 0.23 70.54 9.60 1.07 0.24 11.75 4.88 16.44 0.14 6.95 0.25 0.86 70.62 99.60 2.61 0.05 0.19 8.76 4.38 16.99 99.84 2.10 0.38 12.20 0.44 2.56 0.18 0.21 3.52 4.88 0.11 5.06 9.21 99.65 0.39 0.27 1.74 1.24 2.08 0.24 6.85 14.47 99.65 0.07 8.54 0.88 1.12 1.19 10.61 0.05 15.16 1.89 9.29 9.21 2.69 0.05 99.29 0.10 2.80 0.03 11.17 1.58 6.13 2.20 0.10 99.28 0.07 11.56 2.15 99.55 0.18 1.56 2.69 0.03 0.33 1.32 0.04 99.46 1.99 1.03 11.46 0.03 0.24 1.60 1.37 0.06 23.67 100.04 5.79 0.10 0.33 3.66 0.13 1.29 1.96 1.84 0.13 4.16 99.45 0.14 0.87 98.85 0.34 0.10 8.91 4.71 0.07 99.35 0.13 0.27 3.61 5.04 0.05 99.25 0.34 5.38 0.09 1.70 0.70 99.88 0.07 2.69 1.23 1.10 99.25 3.42 0.38 0.03 99.56 1.16 0.12 1.99 99.10 0.95 0.03 0.56 99.70 0.63 0.09 12.78 99.74 0.12 99.47 1.39 99.28 0.52 99.35 99.25 Table 3. Table

29 OGS REPORT 297 Continued. 91JAA-000691JAA-000891JAA-0009 8091JAA-0039 73 0.3591JAA-0049 13 1830 0.3691JAA-0057 71 1.6792JAA-0066 17 0.20 6791JAA-0068 19 40 13 1379 2.2391JAA-0073 0 39 2.0491JAA-0077 60 50 1860 88 10 991JAA-0094 1.70 47 2200 0.38 891JAA-0102 270 0.24 24 4 591JAA-0105 32 270 5 0.36 70 114991JAA-0109 63 5 135 20 1.32 490 2 50 97491JAA-0113 61 4 43 83 0.78 18791JAA-0119 3 26 84 0.29 18 77 1491JAA-0124 67 9 2 89 47 22 0.81 1630 6191JAA-0127 23 182 1.0 58 19 0.66 991JAA-0135 10 88 267 132 0.32 1.0 12 62 5 19 27691JAA-0136 52 19 2.0 7.0 145 50 1190 0.97 119 491JAA-0137 136 0.0 16 21 2.0 16 0.31 40 7 4691JAA-0139 87 10.0 3.0 54 37 0.31 29 78 135 47 691JAA-0149 83 0.0 17 101 4.0 83 89 0.0 239 0.18 131 3791JAA-0155 100 3.0 0.0 24 21 89 64 0.21 0.0 116 2.0 1291JAA-0161 45 3 95 46 46 5.0 0.38 0.0 71 94 0.0 2091JAA-0163 30 50 187 121 44 0.0 1040 9.0 67 0.14 0.0 22 73 3 36 18 0 69 9.0 2.0 58 39 116 1.06 0.0 1.39 17 42 7 0.0 58 11.0 543 4 39 7 3.0 230 0.99 0.0 1.92 87 565 0.0 34 47 0.0 67.0 5 0.0 1.01 4.66 285 3 940 0.36 2.0 67 49.70 44 55 51 95 145 0.0 26 0.0 17.0 5.59 254 3 136 50 3 0.0 890 15 122 11 2 115 28 98.61 1.10 258 5.0 0.0 15 72 174 0.0 3.0 110 0.0 0.0 2 4.30 43 6 16 4 77.31 93 161 128 1 6 6.0 0.0 2.10 930 145 7.0 0.0 250 33 86 142.51 27.27 2 0.0 0.30 8.73 9 0.0 114 11 0.46 2.0 2 0.0 3656 13 6.11 7 7.0 15 84 0.0 52.68 0.0 1.03 3 93 0.0 0.0 145 66 1.39 18 75 56.49 13.89 1.51 4 2.0 0.0 0.0 2.0 69 2.0 0.0 4 6.0 14.92 6 111.76 32 29.07 4.25 35 43 490 4.0 0.0 145 3.0 74 35.73 25 8.0 13.56 0.55 23 0.0 11 3.0 60 27 145 1.0 34.10 0.0 0.0 1.43 26.07 3.75 170 0.0 19 4.12 18 2.0 45 0.0 58.01 10.42 19 0.0 2.12 11.68 2.09 2.0 0.0 9 340 2.79 6.09 1280 6.15 850 0.47 11 7.24 16 11 23.11 1.61 79.40 24.42 51.94 179.68 51.31 Table 3. Table Sample No.Method Cr AA Be ICP-OES ICP-OES ICP-OES Ni ICP-OES ICP-OES ICP-OES Co ICP-OES AA Sc AA V AA Cu AA Zn ICP-MS ICP-MS ICP-MS Pd Pt Au Ba Y La Ce

30 NORTHERN SWAYZE GREENSTONE BELT Continued. Sample No.Method Cr AA Be ICP-OES ICP-OES ICP-OES ICP-OES Ni ICP-OES ICP-OES Co ICP-OES AA Sc AA V AA Cu AA Zn ICP-MS ICP-MS Pd ICP-MS Pt Au Ba Y La Ce 91JAA-016891JAA-0170 8491JAA-0173 5391JAA-0176 0.53 4591JAA-0184 0.30 283 8491JAA-0185 0.33 32 0 0.2391JAA-0193 25 36 091JAA-0196 13 1.01 120 294 1691JAA-0197 43 1.12 340 40 19 0.3591JAA-0198 3 95 58 44 0.1991JAA-1010 18 31 197 83 90 291JAA-1024 0.57 1920 100 366 16 20 0.3291JAA-1047 213 40 1700 14 0.18 1 54 3891JAA-1060 10 34 88 72 38 64 0.14 10191JAA-1074 737 137 18 38 14 2 90 100991JAA-1095 34 0.36 0.0 97 228 74 69 99 1691JAA-1116 0.0 209 0.52 68 123 42 55 13 4 0.091JAA-1136 0.0 0.30 95 23 5.0 210 90 0.0 137 23 0.2191JAA-1168 18 260 41 2.0 77 0.0 90 36 129 67 0.1591JAA-1174 88 5.0 39 6.0 67 58 53 34 87 3991JAA-1215 0.22 99 36 220 0.0 127 0.0 0.0 113 10.0 26 0.0 4091JAA-1218 37 18.0 1.20 1600 70 70 304 69 43 40 291JAA-2007 86 16 0.0 1.50 0.0 8.0 60 66 130 322 18.0 42 74 0.10 23 10 0.0 36 55 264 49 20 5.0 99 0.0 11 0.0 10.0 8.38 0.0 34 0.65 961 221 15 2.0 9 7 11.56 44 0.0 132 220 0.69 32 21.50 5.0 6 335 6.0 545 8.0 68 125 23 4.69 112 2.82 26.21 95 4 92 231 4.0 105 0.0 9 3.0 67 18 6.0 2.0 4 13 13 13.01 22 8 7.76 76 16 36 107 0.0 195 0.0 72 5 505 15.10 2.0 0.0 27.12 88 21 40 3.88 8 13.0 1.71 0.0 68 12 15 3.0 1.0 34.73 56.05 5 20 0.0 10.89 14.0 60 40 38 35 7 5.03 5.0 12.05 0.0 65 1.0 80 32 6.0 2.47 3.0 52 40 5 0.44 25.76 6 1.0 65 0.0 8.0 27 125 7.06 45 7 7.0 0.0 0.19 1.37 27 5.0 38 0.0 45 3.60 22 17 7.0 39 0.0 0.75 0.0 200 0.0 3.08 10.29 13 2.83 0.0 0.0 2.62 0.0 0.0 20 580 9.58 1.39 8.20 335 7.21 0.0 45 0.0 2.40 6 3.95 0.0 3 7 590 6.80 29.56 190 13.71 0.61 11 63.86 28.02 6 11.07 1.74 12.57 24.64 28.76 Table 3. Table

31 OGS REPORT 297 Continued. Sample No.Method Pr ICP-MS ICP-MS Nd ICP-MS Sm ICP-MS ICP-MS Eu ICP-MS ICP-MS Gd ICP-MS ICP-MS Tb ICP-MS ICP-MS Dy ICP-MS Ho Er Tm Yb Lu Table 3. Table 91JAA-000691JAA-000891JAA-0009 0.7691JAA-0039 0.90 10.7491JAA-0049 4.7891JAA-0057 0.22 5.1991JAA-0066 1.01 39.92 13.8991JAA-0068 1.82 1.3591JAA-0073 4.76 1.80 6.09 4.2691JAA-0077 0.95 45.71 0.8691JAA-0094 0.20 0.64 15.18 0.6491JAA-0102 1.38 0.25 0.84 6.24 4.97 11.2691JAA-0105 2.77 0.10 1.31 1.8891JAA-0109 2.54 3.35 0.23 3.32 1.4591JAA-0113 1.02 0.66 1.71 42.38 0.4591JAA-0119 0.94 4.23 1.59 0.47 13.71 0.4491JAA-0124 0.37 0.64 4.49 0.58 0.63 3.68 5.76 3.82 3.2991JAA-0127 0.23 17.03 0.14 0.17 1.13 2.86 3.1991JAA-0135 6.18 1.69 21.77 0.21 0.0791JAA-0136 1.40 0.44 2.10 1.57 1.41 0.80 1.34 3.83 1.3191JAA-0137 0.88 1.78 0.74 0.84 0.11 22.55 0.28 5.61 0.3991JAA-0139 0.92 0.97 2.18 2.36 0.47 0.37 3.25 8.6691JAA-0149 0.98 0.55 0.28 1.10 2.16 0.16 0.60 9.58 2.77 0.63 3.6291JAA-0155 1.05 0.06 1.46 0.34 0.15 5.27 0.40 2.7591JAA-0161 0.34 1.88 0.29 2.72 0.85 0.33 0.17 5.45 3.46 1.2191JAA-0163 0.09 0.09 6.05 3.11 0.89 0.40 0.19 2.26 5.59 6.22 1.03 1.22 5.60 1.86 0.64 1.61 0.12 0.92 0.33 2.19 1.84 21.73 0.81 0.29 1.90 0.52 0.25 0.55 23.01 0.02 1.18 2.74 0.35 2.54 0.15 2.06 0.26 0.99 1.87 19.50 0.72 0.84 0.26 0.33 2.43 3.74 0.81 91.67 0.03 0.71 0.08 0.68 0.14 3.60 0.22 5.87 0.54 3.82 0.96 0.34 0.81 0.30 0.88 6.16 0.12 0.59 3.17 2.37 0.51 15.79 0.29 0.08 0.34 0.59 0.03 1.02 0.67 2.56 1.54 0.83 0.13 0.11 0.66 1.96 1.99 1.26 0.07 2.98 0.62 1.49 0.43 0.04 0.60 3.77 4.30 1.18 1.91 0.22 0.22 0.46 0.82 0.29 2.64 4.77 0.38 3.45 0.52 0.21 0.52 0.07 2.06 3.23 10.15 0.95 0.25 0.68 1.53 0.20 0.12 3.27 1.09 1.07 0.50 0.34 0.07 1.48 3.49 0.74 0.29 2.70 1.73 0.09 1.10 0.21 1.58 3.27 0.15 3.10 3.21 1.93 0.22 3.49 2.16 0.38 0.21 1.73 0.68 5.16 1.58 3.27 1.04 0.47 0.47 1.93 3.49 0.31 2.41 0.10 1.73 5.16 1.58 0.31 0.17 3.08 1.93 0.30 2.33 0.35 1.73 5.16 0.12 2.18 0.43 0.15 2.08 0.32 0.15 0.22 0.81 0.31 1.10 0.30 1.26 1.30 0.09 0.16 0.19 0.18

32 NORTHERN SWAYZE GREENSTONE BELT Continued. Sample No.Method Pr ICP-MS ICP-MS Nd ICP-MS Sm ICP-MS ICP-MS Eu ICP-MS Gd ICP-MS ICP-MS Tb ICP-MS ICP-MS Dy ICP-MS ICP-MS Ho Er Tm Yb Lu Table 3. Table 91JAA-016891JAA-0170 2.8391JAA-0173 2.8991JAA-0176 13.23 1.9691JAA-0184 13.23 1.1091JAA-0185 3.33 10.37 6.1691JAA-0193 2.83 5.87 4.1291JAA-0196 3.47 22.57 1.12 1.5791JAA-0197 17.02 0.72 1.89 0.8491JAA-0198 3.62 1.12 8.55 3.02 3.1491JAA-1010 3.49 4.55 1.14 2.71 0.7091JAA-1024 12.47 0.83 2.67 0.26 4.6091JAA-1047 0.49 1.01 1.67 6.24 0.17 2.3491JAA-1060 0.33 2.69 1.55 1.62 2.38 0.9691JAA-1074 0.81 3.02 2.13 1.07 1.54 2.76 0.6391JAA-1095 1.80 0.38 0.77 0.64 8.82 1.28 3.3391JAA-1116 0.33 5.71 0.61 0.47 9.21 1.07 0.8091JAA-1136 2.31 0.40 0.36 2.65 3.05 2.83 0.64 2.64 0.2191JAA-1168 2.00 0.57 1.29 1.59 3.63 5.47 1.02 0.1691JAA-1174 2.98 2.57 0.41 1.18 0.59 2.22 3.43 6.87 1.13 1.0391JAA-1215 0.41 0.22 0.41 3.61 3.91 1.76 5.77 3.08 1.32 0.7491JAA-1218 0.51 0.18 0.50 2.85 26.49 1.71 1.16 0.28 0.80 4.0691JAA-2007 2.66 0.19 1.56 0.54 1.17 12.40 0.85 1.97 2.82 0.69 5.28 0.13 1.61 1.39 4.30 3.43 0.25 0.65 1.61 2.70 0.45 3.04 0.22 0.70 3.49 0.18 0.56 2.27 1.32 11.67 2.33 0.65 2.43 0.24 0.92 0.18 0.99 1.76 10.36 0.75 0.86 1.74 0.63 1.88 0.53 0.54 1.33 1.50 2.43 4.95 0.33 0.28 0.83 2.57 0.41 1.20 1.90 0.24 6.28 0.26 0.21 2.05 2.81 0.23 0.19 0.31 0.23 3.76 2.20 0.74 1.11 0.72 1.47 0.16 0.45 2.94 1.71 0.31 1.35 0.60 0.55 0.92 0.29 1.45 0.30 2.27 0.10 0.83 3.03 2.23 0.16 0.29 3.31 1.92 0.08 0.66 3.91 1.49 0.24 1.43 0.16 0.73 0.47 0.51 2.34 0.30 0.72 0.31 0.55 0.61 0.72 1.83 0.19 0.23 0.10 1.25 3.14 0.34 1.43 1.93 0.10 0.08 4.08 0.29 2.15 1.07 0.53 0.48 2.34 0.21 0.26 0.38 0.23 0.60 1.86 0.31 0.06 0.20 0.36 1.47 0.76 0.02 1.13 0.29 2.10 0.36 0.53 0.23 0.10 0.18 0.15 0.29 0.05 0.07 0.74 0.02 1.05 0.47 0.10 0.17 0.05

33 OGS REPORT 297 LOI Total 5 O 2 OP 2 ent values in ppm. OK 2 MnO MgO CaO Na 3 O 2 Fe 3 O 2 Al 2 TiO 2 Whole-rock geochemical data from Muskego and Keith townships. Major element oxide values in weight %, trace rare earth elem Sample No. SiO Method XRF XRF XRF XRF XRF XRF XRF XRF XRF XRF Table 4. Table 92JAA-001892JAA-004592JAA-0047 36.8092JAA-0066 54.0092JAA-0109 48.4092JAA-0141 55.30 0.1292JAA-0142 75.90 1.1392JAA-0151 39.10 0.8292JAA-0173 64.30 0.6492JAA-0194 1.34 43.70 14.90 0.2092JAA-0198 51.10 15.00 0.1392JAA-0199 75.00 17.10 0.5492JAA-0221 50.80 8.07 12.60 0.4292JAA-0229 8.32 54.60 0.96 11.6092JAA-0231 1.51 39.70 16.10 0.3192JAA-0237 9.36 52.10 0.6992JAA-0248 0.10 8.35 1.52 38.10 0.18 13.00 1.4892JAA-0249 0.18 51.30 8.24 14.40 0.8292JAA-0250 4.03 44.50 0.22 13.30 0.7592JAA-0252 11.70 37.80 49.00 0.04 14.50 0.20 13.3092JAA-0253 6.57 50.80 11.10 0.75 7.6392JAA-0258 0.13 1.57 39.00 0.06 14.10 0.42 11.8092JAA-1017 3.26 53.50 0.23 0.69 11.4092JAA-1030 0.23 2.89 0.76 0.21 67.60 13.90 0.86 10.3092JAA-1043 9.14 36.80 11.00 35.40 0.06 0.10 12.0092JAA-1052 7.74 2.27 0.27 73.90 11.70 1.34 20.6092JAA-1053 6.94 0.23 46.60 8.42 13.80 0.57 11.50 8.0392JAA-1073 0.01 2.03 0.22 48.80 0.1292JAA-1097 2.66 1.37 1.35 13.30 0.39 1.90 0.20 47.60 15.20 0.09 11.20 7.3192JAA-1116 3.80 53.00 7.74 14.40 0.87 11.90 5.0292JAA-1134 2.89 0.12 0.25 48.00 -0.01 7.76 0.84 5.2192JAA-1143 2.84 1.50 73.10 7.99 0.21 14.30 -0.01 0.73 12.00 0.12 6.9792JAA-1144 0.37 0.03 12.90 0.17 74.70 13.70 0.8792JAA-1156 7.05 3.95 34.00 0.19 69.80 0.03 8.68 13.80 0.75 0.02 0.83 7.5392JAA-1157 12.40 13.30 60.70 0.76 11.80 0.12 1.44 19.9092JAA-1162 0.12 0.15 1.64 0.07 0.17 -0.01 42.60 12.30 8.92 14.70 0.29 20.7092JAA-1170 3.88 2.01 51.60 0.05 15.60 0.34 12.60 0.48 7.12 14.7092JAA-1180 1.87 0.17 66.50 0.03 2.17 9.18 0.17 15.20 0.48 12.4092JAA-1193 0.07 40.00 0.76 56.80 0.02 2.45 0.03 7.98 0.03 12.60 2.40 0.35 3.49 8.44 6.77 0.62 69.10 2.75 15.80 0.74 12.30 2.32 0.12 0.24 1.86 10.30 0.18 69.40 2.00 0.05 16.70 0.36 99.18 35.20 0.01 1.10 0.19 0.70 1.60 1.36 12.30 0.08 1.80 0.33 0.34 5.95 1.83 0.46 99.59 0.07 5.39 0.15 99.03 14.30 0.25 5.32 0.08 2.24 3.21 0.05 0.20 0.59 1.10 12.00 0.36 7.88 2.20 5.20 3.94 3.31 98.71 11.80 0.82 0.14 0.03 16.10 0.02 5.32 11.30 0.07 0.07 99.00 99.59 0.04 16.60 -0.01 11.90 1.36 7.96 0.02 1.45 4.53 9.35 0.06 0.04 15.30 0.95 7.84 0.05 4.86 99.85 9.33 0.08 8.71 0.02 0.21 98.05 1.00 9.11 0.36 6.86 -0.01 18.40 0.06 0.19 100.54 1.52 0.90 0.21 0.04 0.04 3.84 8.06 0.75 2.93 -0.01 0.78 0.06 11.60 100.32 99.83 1.20 0.13 12.40 2.59 0.08 2.42 0.14 0.05 26.10 -0.01 100.22 2.04 99.92 2.45 2.65 0.04 0.02 7.57 1.38 5.10 0.11 0.08 3.00 2.65 3.12 2.67 99.19 2.43 1.40 0.23 1.85 4.22 0.13 98.05 0.02 3.85 0.04 5.65 11.50 5.74 0.14 98.35 0.98 11.00 3.65 2.32 0.04 99.28 1.59 0.09 98.14 1.57 4.90 6.81 0.42 13.00 100.42 0.60 0.08 5.70 5.83 0.07 100.47 0.37 1.93 3.05 2.17 1.40 3.22 99.37 2.58 0.36 1.20 0.06 2.56 3.54 100.12 2.65 98.61 3.20 3.28 3.68 0.05 0.03 5.75 0.07 0.21 99.71 1.10 1.10 6.78 0.12 99.87 1.17 0.28 98.62 0.20 0.03 97.43 1.45 0.06 0.90 2.53 99.33 0.80 99.27 0.80 0.08 0.35 0.16 6.75 99.87 0.80 0.10 98.25 0.08 100.05 2.20 98.32 0.75 99.32 100.56 0.35 0.65 100.08 99.67 100.27 100.55

34 NORTHERN SWAYZE GREENSTONE BELT XRF XRF XRF ICP XRF XRF XRF ICP-MS ICP-MS ICP-OES ICP-OES ICP-OES ICP-OES ICP-OES ICP-OES ICP-OES ICP-OES ICP-OES Continued. Sample No.Method Be Cr Sc Cu Zn Bi Mo As Sb Rb Ba Sr Li Nb Zr Th U La Table 4. Table 92JAA-001892JAA-0045 0.8092JAA-0047 1.1092JAA-0066 6680 1.5092JAA-0109 1.70 49792JAA-0141 0.90 227 792JAA-0142 0.80 4592JAA-0151 1.10 0 40 4792JAA-0173 1710 1.40 1092JAA-0194 1.60 111 13 8992JAA-0198 2410 1.10 104 4 992JAA-0199 1.40 12 225 10992JAA-0221 103 1.80 9 33 90 1792JAA-0229 1.30 4.00 445 20 -3.00 4 4292JAA-0231 1.50 12892JAA-0237 5.00 24 0.90 0 42 -1.00 158 4 -1.00 4592JAA-0248 1.50 -3.00 25 45 76 9792JAA-0249 -1.00 1950 1.40 17.00 110 61 97 -3.00 4092JAA-0250 1.30 -3.00 1.00 6.00 94 392JAA-0252 2990 1.60 53 89 0 8.00 7.00 13 -3.00 -5.00 5.0092JAA-0253 1510 0.80 -1.00 -1.00 10 -3.00 85 10892JAA-0258 1.70 -5.00 30 4.00 -1.00 29 214 8 -1.00 45 131 992JAA-1017 1.20 -5.00 -3.00 29 -3.00 39 121 -3.0092JAA-1030 1.30 62 0 -3.00 9 -1.00 194 -3.00 -3.00 3992JAA-1043 149 81 42 -5.00 1.50 69 -5.00 12 69 -1.00 6.00 44 6492JAA-1052 371 5430 2.40 -3.00 -1.00 30.00 -5.00 47 8.00 4392JAA-1053 69 8 213 11 183 1.60 4.00 15 108 34 -3.00 79 1492JAA-1073 3.00 4.00 -1.00 1.60 -5.00 14 -3.00 69 302 10 9 7 20.00 15792JAA-1097 499 2.10 371 -1.00 119 260 80 -5.00 1.00 4.00 -3.0092JAA-1116 -1.00 -3.00 75.00 -5.00 1.40 4 62 453 7 -3.00 792 1 108 10.00 4092JAA-1134 4.0 14.00 167 1.40 14 61 -3.00 343 -1.00 -1.00 2.0 40 9892JAA-1143 -5.00 -5.00 61 29.00 30 5 1.50 -1.00 374 4.00 297 35 55 2.0 3892JAA-1144 11.00 31 1.20 80 4.0 -5.00 159 27 19 36 -3.00 2 -3.00 -3.00 21 1292JAA-1156 64 458 7.00 3.00 1.00 -1.00 8 -3.00 9.00 47 74 39 221 2192JAA-1157 4.00 19.00 21 58 2.0 163 0.80 1.10 155 -5.00 -5.00 76 -1.00 320 115 2092JAA-1162 -3.00 168 1.50 7 89 -5.00 2.0 31 0.10 -3.00 1 7.0 26 22.00 3.00 -1.00 7892JAA-1170 153 0.10 0.90 1.80 2.0 2240 133 1.10 82 116 10 3 7 -3.00 -1.00 3.00 14092JAA-1180 112 1.40 0.10 84 -5.00 -3.00 7.00 7.00 4 152 167 3 98 -1.00 3.80 2.0 0.07 0.5092JAA-1193 2.20 7 239 1.70 5.00 94 141 9.00 21 6 -5.00 10.00 15.00 2 77 18 97 -3.00 2.0 0.30 10 1.10 -3.00 -1.00 98 15.20 -1.00 6.0 17 2.10 3.20 18.00 0.60 54 0.10 63 0.00 99 62 12.00 50 9.00 -1.00 5.00 22 -5.00 8 -3.00 2.0 3.0 33 -1.00 145 35 11.30 129 -3.00 0.60 34 155 14 37 -3.00 6 0.10 9 7.00 30 38 0.90 2.0 56 -1.00 2.00 89 9 -3.00 194 46 -1.00 17.20 4 80 57 0.00 -5.00 -3.00 14.00 224 4.00 40 -5.00 -3.00 0.30 9.00 2 0.10 8 -3.00 75 67 -5.00 2.0 46 12 -3.00 -3.00 8.00 5 -3.00 68 75 0.90 0.00 -5.00 14 84 1.30 -1.00 61 2.0 158 90 8.00 3.40 2.0 -1.00 -3.00 -5.00 84 0.20 6 4.00 -1.00 12.80 -5.00 14 2.0 4 0.10 76 686 137 5 -3.00 19.00 163 -3.00 15 189 45 2.0 4 -1.00 31 -3.00 49 0.10 -1.00 19 -3.00 0.10 4.10 12 94 -3.00 52 -1.00 -5.00 -3.00 193 110 3.0 -1.00 46 98 0.50 2.00 1002 -5.00 66 0.00 -3.00 1.90 26 -5.00 -3.00 0.10 -1.00 0.30 72 67 178 -1.00 1.00 16.00 -3.00 -3.00 0.10 2.0 76 94 7.00 96 1.00 -5.00 8.0 546 14.00 64 0.40 -3.00 0.10 12.00 -3.00 762 -5.00 110 1.90 2.0 3.0 -3.00 -1.00 1.10 82 0.13 19.00 724 155 26.00 7.0 1048 5 -1.00 4 2.50 -5.00 11 18.00 2.0 -5.00 416 1483 -3.00 0.10 3.70 57 2.90 2.0 288 7 6.0 0.20 398 61 -3.00 40 86 40 2.0 22.00 1410 -5.00 3.90 57 96 0.50 0.80 17.00 164 0.10 0.10 14.00 49 4.40 -5.00 324 10.00 489 80 15.90 4.0 1.40 40 0.05 26 0.10 0.30 5.60 2.0 93 1.20 0.50 30 3.0 10.0 340 0.10 161 865 2.30 0.70 24.00 58 0.20 1.10 5.00 101 0.10 145 8.00 317 227 3.60 43.00 52.70 0.10 6.00 824 0.00 2.90 2.70 2.0 0.00 2.0 390 0.00 2.30 3.0 27.00 7.0 0.80 19 46 6.00 16.20 123 143 6.0 0.20 0.00 2.0 1.30 2.00 119 0.10 0.10 99 0.40 0.00 0.60 12.60 3.80 0.00

35 OGS REPORT 297 Continued. Sample No.Method Ce ICP-MS ICP-MS Pr ICP-MS Nd ICP-MS ICP-MS Sm ICP-MS ICP-MS Eu ICP-MS ICP-MS Gd ICP-MS ICP-MS Tb ICP-MS ICP-MS Dy Ho Er Tm Yb Lu Negative numbers indicate that the content is below detection limit of analytical method used. Table 4. Table 92JAA-001892JAA-004592JAA-0047 0.9092JAA-0066 10.5092JAA-0109 9.5092JAA-0141 35.20 0.1092JAA-0142 1.40 25.3092JAA-0151 1.30 0.8092JAA-0173 3.70 35.50 0.5092JAA-0194 2.50 7.1092JAA-0198 0.10 6.50 9.7092JAA-0199 14.70 3.50 28.8092JAA-0221 0.20 9.30 2.3092JAA-0229 12.30 1.30 0.5092JAA-0231 2.10 12.80 2.90 2.8092JAA-0237 -0.05 1.90 5.90 0.8792JAA-0248 1.60 6.50 1.1092JAA-0249 0.20 10.30 2.60 0.71 0.97 6.0092JAA-0250 0.20 0.80 0.5292JAA-0252 3.00 8.00 0.10 6.4092JAA-0253 2.20 2.00 0.06 10.50 0.94 2.90 3.10 0.9092JAA-0258 -0.10 4.50 0.8092JAA-1017 1.70 0.40 11.50 2.70 0.80 0.8092JAA-1030 0.75 1.40 38.20 0.40 0.30 2.40 4.50 0.4092JAA-1043 0.30 0.20 0.10 0.8092JAA-1052 1.60 1.60 0.20 50.50 3.20 4.00 1.0392JAA-1053 0.30 3.80 7.00 2.90 -0.10 1.60 6.8092JAA-1073 1.60 3.20 0.30 2.20 -0.05 0.10 0.40 9.9092JAA-1097 0.56 4.90 5.00 1.00 7.6092JAA-1116 1.50 14.70 0.63 120.00 3.40 0.12 2.20 0.30 1.00 0.4092JAA-1134 0.20 0.50 1.70 0.59 0.38 1.20 0.50 6.7092JAA-1143 0.20 0.10 17.10 2.30 2.80 12.70 1.0092JAA-1144 0.17 3.20 0.48 1.80 0.50 34.70 0.50 5.40 0.7792JAA-1156 3.10 0.06 1.00 2.30 0.29 1.80 0.90 6.3092JAA-1157 0.20 1.10 -0.10 3.20 0.05 48.70 5.00 0.30 0.9092JAA-1162 0.50 3.40 0.87 2.10 0.30 3.60 0.10 1.9092JAA-1170 1.90 2.90 0.63 0.20 0.17 4.70 0.3092JAA-1180 2.00 0.80 0.30 0.10 0.03 0.10 8.50 27.60 0.61 0.3092JAA-1193 1.70 2.60 11.50 3.60 11.50 0.10 1.80 3.00 0.30 0.30 0.50 0.72 0.68 0.40 -0.10 1.80 -0.05 1.70 0.50 1.90 2.40 0.78 0.10 0.90 2.90 0.20 -0.10 2.24 2.70 1.90 0.59 1.70 0.56 0.50 0.80 0.25 1.40 2.40 0.40 2.20 0.11 2.60 0.20 3.00 0.30 0.27 11.30 0.61 0.10 0.80 0.27 0.49 2.60 -0.10 0.30 7.00 0.30 8.90 0.48 2.20 0.16 3.90 1.70 0.60 2.20 0.48 0.04 0.30 0.30 0.40 2.00 0.60 2.50 0.60 0.11 2.20 1.40 0.20 0.40 0.05 1.30 0.70 3.30 1.40 0.30 0.30 0.78 0.21 2.50 0.39 1.40 0.10 0.31 2.90 0.13 1.70 0.67 0.30 0.20 2.70 0.05 0.20 3.30 0.18 1.23 2.00 2.30 0.10 2.30 0.90 0.43 1.00 0.20 0.40 0.58 0.30 2.40 1.50 2.50 0.53 0.10 -0.10 0.53 0.50 0.38 4.50 0.70 0.45 0.30 -0.05 0.10 1.60 0.20 1.90 1.70 0.25 0.30 0.51 -0.10 0.20 1.50 1.40 0.10 0.70 2.40 0.10 1.20 0.54 1.10 1.10 0.36 0.30 -0.05 2.00 0.20 1.60 0.20 0.80 0.20 0.39 5.00 0.30 0.20 0.19 0.22 1.80 -0.05 0.36 0.20 1.50 0.13 1.40 -0.10 1.30 1.05 0.60 0.30 1.10 1.70 0.20 0.20 0.30 0.21 3.10 0.10 0.26 0.10 -0.05 0.50 0.70 1.20 3.50 0.15 0.17 0.49

36 NORTHERN SWAYZE GREENSTONE BELT 8.26 8.09 11.81 80.03 98.12 71.79 23.10 51.21 41.03 79.82 85.89 99.82 Ni 117.8 162.6 152.7 134.0 132.3 758.6 157.6 203.2 450.1 1444 1335 1321 1779 1024 ICP-OES race and rare earth element values in ppm. SBaCrBeCoCuMo 2 LOI TOTAL CO 3 O 2 Fe 5 O 2 P 2 OTiO 2 OK 2 MnO MgO CaO Na 3 O 2 Al 2 Whole-rock geochemical data from Reeves, Penhorwood, Sewell and Kenogaming townships. Major element oxide values in weight %, t Sample No. SiO Method XRF XRF XRF XRF XRF XRF XRF XRF XRF XRF AA AA AA AA AA AA 93JAA-1001 51.2993JAA-1005 15.44 52.56 0.1993JAA-1006 12.53 44.87 6.48 0.1793JAA-1008 20.83 49.48 8.59 4.58 0.1093JAA-1014 13.91 50.20 3.20 6.03 8.92 0.2493JAA-1016 12.14 13.29 0.09 47.82 3.24 7.29 0.1793JAA-1020 14.31 1.17 0.10 10.27 40.65 1.25 9.53 0.2093JAA-1021 0.10 5.41 0.14 6.88 56.87 1.52 2.82 8.1093JAA-1027 0.18 14.07 0.09 3.92 0.11 0.13 48.94 9.30 5.85 25.42 0.1493JAA-1033 14.77 -.05 -.02 14.97 45.00 3.20 0.78 3.09 8.45 4.75 0.2693JAA-1035 3.12 0.63 9.70 0.07 5.62 0.05 45.75 99.16 0.15 6.14 3.6893JAA-1035D 0.22 45.77 0.08 98.93 -0.30 11.44 3.80 5.67 10.95 1.34 2.77 -.02 11.3193JAA-1041 5.68 0.19 10.51 0.58 3.27 1.38 0.04 98.82 0.10 10.01 47.76 -.02 0.24 21.38 0.1993JAA-1042 -0.03 4.94 18.91 -0.30 98.95 67 2.57 -.02 14.41 21.30 48.69 -.05 0.75 9.18 0.2093JAA-1043 -0.03 77 99.73 14.15 0.68 3.98 205 9.24 -.02 0.72 0.14 39.36 0.26 4.29 7.94 0.2293JAA-1046 83 -0.03 1.74 0.26 0.06 0.41 99.25 0.50 4.65 10.54 10.13 42.87 0 -.02 7.79 6.44 13493JAA-1055 616 0.06 -0.30 0.13 53.80 10.32 -.02 0.06 2.62 7.47 10.13 98.59 0.36 67.10 5.24 0.29 32.72 -0.2 17993JAA-1059 -0.03 56 0.16 7.59 15.10 15.54 12.24 0.81 0.29 2.95 43.53 2.87 61.41 -.05 98.66 1.51 22.22 0.33 0.0593JAA-1062 -6 75 34.95 644 98.68 7.16 15.73 -.05 0.61 0.81 0.03 -5 10.13 68.39 2.39 -.01 58.77 7.85 3.04 0.33 -0.293JAA-1068 196 44.18 4.45 98.78 16.53 10.12 0.08 1.17 42 5.12 50.94 0.53 0.04 -6 -.02 1.97 23.80 1.96 -6 0.06 0.4393JAA-1069 48.59 0.06 5.45 3.75 1960 0.11 7.27 7.93 -6 98.01 38.29 52 5.66 -.02 7.47 0.28 1.98 49.67 142.793JAA-1071 -0.2 43 98.33 0.08 0.20 13.69 6.12 4.13 0.71 0.45 67.02 167.2 177 0.97 0.37 -.05 1.99 -6 14.4993JAA-1071D 1.19 34 355 0.78 88.38 0.15 16.54 67.64 99.40 0.03 10.91 -6 1.47 0.60 0.55 1.57 -.05 35.15 16.81 2676 9.78 0.0393JAA-1078 0.28 99.35 0.03 19.65 4.26 1.13 12 27.61 0.22 2.53 0.03 59.74 11.61 10.91 0.59 -0.2 0.74 0.93 -6 93JAA-1083 38.00 0.54 12 2080 15.38 0.44 0.15 0.89 13.10 0.18 5.47 59.38 99.32 0.64 4.16 -.01 2.93 105.3 59.22 223293JAA-1085 0.11 -0.2 422 0.09 -6 17.10 0.36 2.94 0.30 98.60 0.77 48.68 1.82 4.71 -0.2 6.22 -6 -.02 103 4.20 90.65 0.09 221 93.44 15.26 0.05 4.67 -0.30 100.09 -0.03 -6 1.43 1.99 3.75 6.16 0.19 92.83 226 4.16 0.19 0.36 33.13 -0.03 -0.30 1.42 14 9.75 98.32 2.79 0.31 4.07 -.05 4.43 0.42 8.54 33.39 -6 45.16 -0.03 26 3599 0.32 100.53 1.89 0.10 11.39 -6 0.92 0.32 3.54 42.58 10.75 106 2683 94.35 -0.2 0.10 -0.30 98.09 10.32 1.64 109.6 0.44 0.09 0.56 -6 2.24 -0.2 101.80 44 1.02 295 2.26 0.18 0.48 99.69 -6 0.23 2.25 0.63 88.30 499 0.62 5.15 -0.03 -0.30 2.21 141 0.69 0.21 98.50 5.79 15.22 71.75 181 6.38 70 0.41 99.29 0.07 0.70 -6 1.22 2.05 2377 6.26 -5 0.73 74 21.10 11.50 1.16 -0.03 -0.2 99.21 2.64 4559 16.45 -0.03 0.79 516 33.05 -6 -0.30 51.58 98.88 -0.2 515 -6 19.95 98.94 0.13 -0.30 49.09 0 -6 124.0 -0.30 341 -0.03 0 -6 0.92 129.8 0.03 307 114 0.93 5.50 6.95 76 0.90 89 5.43 330 4.88 21.01 0.76 4.39 -6 0.26 33.45 22.65 -6 -6 43.39 48.21 72.35 -6 -6 Table 5. Table

37 OGS REPORT 297 94.24 31.88 70.22 33.14 72.57 77.14 60.32 Ni 127.6 326.9 179.4 178.6 121.5 185.7 132.9 582.8 201.1 1255 1767 1985 1707 1272 1252 1744 2737 2886 1460 ICP-OES SBaCrBeCoCuMo 2 LOI TOTAL CO 3 O 2 Fe 5 O 2 P 2 OTiO 2 OK 2 MnO MgO CaO Na 3 O 2 Al 2 Continued. 93JAA-1086 60.0793JAA-1090 15.36 47.17 0.0993JAA-1095 13.88 49.05 4.84 0.2893JAA-1096 13.64 46.25 6.52 5.37 0.1893JAA-1097 7.27 42.21 2.72 7.86 7.4893JAA-1100 0.20 7.51 1.00 53.08 1.32 9.62 19.2593JAA-1101 0.14 15.54 0.06 47.17 0.52 1.45 8.86 23.50 0.1593JAA-1101D 13.36 47.21 0.13 2.13 1.91 0.34 5.18 5.02 13.34 0.2093JAA-1102 0.21 0.02 0.20 65.86 0.61 0.51 5.58 5.20 8.4693JAA-1104 15.27 16.92 8.59 0.06 0.82 48.72 1.79 0.37 4.63 8.10 0.0793JAA-1106 15.42 -0.05 3.63 8.10 12.74 0.30 55.77 98.61 0.38 1.52 1.78 0.1893JAA-1107 15.71 1.52 11.37 -0.05 98.60 1.72 -0.02 -0.30 46.62 1.00 5.35 8.28 0.1293JAA-1108 -0.02 3.95 15.15 -0.03 1.12 98.70 1.06 0.15 9.96 40.13 3.16 9.82 4.37 0.1793JAA-1109 305 1.06 -0.30 97.91 0.12 0.10 8.60 4.85 0.82 38.44 2.06 9.45 3.88 9.2293JAA-1111 134 0.10 -0.30 0.03 0.11 13.20 56 98.85 3.67 10.93 0.13 41.16 5.20 0.48 4.96 33.28 -0.03 227 13.21 0.6593JAA-1112 0.12 5.65 148 1.19 0.71 5.31 0.16 0.09 46.35 99.70 0.78 3.46 30 35.79 23.02 5.66 13093JAA-1113 98.81 0.11 12.77 0.38 0.04 0.03 0.08 2611 2.14 51.32 1.13 0.15 4.29 1.64 29.11 99.00 53.96 0.22 0.2393JAA-1114 106 58.11 3.75 13.83 -0.2 0.59 -0.02 -0.03 11.66 0.23 -6 41.84 1.62 0.02 43.65 3.65 6.45 3.73 1127 0.2093JAA-1114D 85.10 0.03 41.82 0.06 1.76 62 -0.02 0.24 6.63 71.60 98.87 0.06 8.25 -0.2 8.95 24.98 6.54 0.03 -6 93JAA-1115 6.61 61 -0.05 0.16 11.06 98.88 100 -0.02 -0.30 0.20 -6 39.73 5.27 2.15 9.79 4.09 69 25.64 0.16 71.4093JAA-1117 3.69 114 -0.05 -0.30 -0.03 0.81 9.15 -0.02 0.29 25.77 4.51 -6 49.39 99.78 1.78 5.87 119 13.9393JAA-1118 190 0.32 98.72 0.06 -0.05 0.14 15.16 33.13 8.96 8.42 5.85 0.71 -6 0.55 2.33 38.62 0.35 0.32 32.06 109 0.2593JAA-1119 48.39 100.36 12.20 0.35 67 0.34 0.07 9.37 -0.03 1.32 8.40 0.05 35.91 0.84 48.89 2.75 100.51 4.28 -0.30 17893JAA-1121 63.35 0.06 0.12 0.73 -6 0.05 10.84 9.41 88 1.60 0.09 10.52 48.32 0.36 0.06 63.15 -6 0.50 41.29 0.03 0.2693JAA-1122 10.53 76 13.20 0.07 0.36 98.51 -0.05 -6 1.03 -0.02 12.84 4.57 49.36 94 45.72 0.21 0.03 43 41.1793JAA-1124 99.03 -0.05 407 20.56 -0.30 -0.02 0.15 10.16 1.32 0.25 -0.01 4.19 146.8 1891 0.62 44.28 23 0.34 -6 21.20 10.17 5.95 0.24 0.05 -0.05 0.07 7.52 0.78 13.53 -0.02 99.09 -0.2 -0.01 -6 26.76 1706 9.47 -0.03 25.72 7.61 48.02 0.11 32 0.07 -0.30 98.62 -0.02 -0.2 0.04 9.75 -0.01 84.94 90.90 14.11 114.9 76 3.90 1551 98.78 -0.03 -0.05 -0.30 10.39 10.44 -6 -0.02 15.28 0.02 94.36 -0.01 -0.2 -6 -0.30 106 124 9.12 6.52 0.03 -0.05 99.72 0.21 7.86 -0.02 0.21 6.27 0.03 5.11 0.23 90.77 10.33 98.40 29 43 -0.05 0.55 0.03 5.39 0.09 6.61 26.91 22 2468 99.75 15.02 2.99 0.26 5.05 0.09 -0.05 0.16 8.61 2453 -0.2 99.50 -6 43.40 -0.05 0.34 99.49 0.10 18 4.98 -0.2 8.63 -6 154.8 90.90 2034 0.06 1.80 59 5.62 97.54 5.90 89.82 -0.2 -6 42 0.12 416 7.50 -0.30 5.33 97.85 2488 7.74 -6 93.07 -0.03 30 0.27 -0.30 98.68 -6 -0.2 17.44 17 56.68 -0.03 733 1.42 -6 1674 124.2 -0.2 14 61.09 -0.03 -0.2 -6 2043 51 101.6 8.63 -0.2 14 78.28 1982 13.76 94.70 0.22 -5 7.52 41.07 20.35 -6 -6 3.73 -6 Table 5. Table Method XRF XRF XRF XRF XRF XRF XRF XRF XRF XRF AA AA AA AA AA AA Sample No. SiO

38 NORTHERN SWAYZE GREENSTONE BELT Continued. Sample No.Method Sc ICP-OES ICP-OES V ICP-OES ICP-OES ICP-OES ICP-OES Y ICP-MS ICP-MS ICP-MS Zn ICP-MS ICP-MS ICP-MS Sr ICP-MS ICP-MS ICP-MS W La Ce Pr Nd Sm Eu Tb Gd Dy 93JAA-100193JAA-1005 41.3693JAA-1006 40.8293JAA-1008 269.7 19.4693JAA-1014 445.9 38.83 25.7593JAA-1016 52.60 33.36 21.6693JAA-1020 257.1 164.8 44.9393JAA-1021 2.82 203.5 72.11 17.60 17.0893JAA-1027 322.4 142.8 18.42 40.84 14.4493JAA-1033 59.53 118.3 143.1 37.82 -35 22.4193JAA-1035 133.5 124.7 72.38 30.17 -3593JAA-1035D 6.20 251.5 70.49 5.09 136.6 20.33 13.79 -3593JAA-1041 199.9 31.77 20.35 4.05 -35 73.54 14.40 14.9393JAA-1042 135.2 50.77 104.4 0.36 28.08 -35 11.33 134.5 11.4193JAA-1043 2.37 2.27 93.01 81.26 41.34 -3593JAA-1046 6.90 177.6 182.3 0.87 3.46 1.74 66.77 15.79 6.88 10.55 -3593JAA-1055 6.64 308.0 137.4 3.41 23.01 -35 59.72 12.76 0.1593JAA-1059 8.14 8.32 58.32 114.7 59.51 3.44 0.46 1.03 -35 7.32 22.6693JAA-1062 9.81 167.9 9.99 29.01 75.26 0.62 15.05 1.16 -35 2.6993JAA-1068 1.05 3.52 28.48 1.26 5.23 2.02 66.08 119.8 12.02 1.58 22.72 -3593JAA-1069 8.13 109.5 229.2 0.25 0.66 5.36 2.87 0.76 -35 43.30 77.12 0.2093JAA-1071 1.84 5.90 88.30 158.2 8.19 9.97 2.91 0.42 11.96 -35 0.21 66.61 0.58 12.8693JAA-1071D 1.62 6.64 4.39 0.40 189.2 0.61 1.20 0.99 -35 8.56 12.30 3.47 13.2393JAA-1078 44.72 2.70 102.8 1.33 0.05 2.70 3.26 19.67 3.49 0.58 145.3 5.15 0.91 1.3193JAA-1083 0.42 8.92 -35 0.53 4.97 4.12 31.65 1.00 95.13 2.91 14.34 203.1 4.02 0.32 0.25 -3593JAA-1085 7.47 0.38 31.23 3.11 329.5 4.22 0.26 2.46 14.44 0.20 85.31 11.07 0.23 1.68 0.87 0.63 -35 103.9 234.4 0.36 3.50 1.39 0.39 2.19 38.74 1.22 -35 85.81 3.51 1.34 3.01 1.42 114.6 0.14 1.70 47.83 0.73 0.68 17.29 3.60 0.46 -35 11.30 57.56 2.56 17.64 232.5 0.64 1.32 6.14 0.48 58.34 2.05 0.74 11.78 0.65 -35 39.24 4.29 0.37 8.16 38.88 2.97 0.12 85.13 39.65 264.9 0.16 15.31 0.24 1.89 0.32 -35 1.02 269.4 0.16 77.51 85.35 2.81 1.99 2.22 4.82 2.71 0.75 4.88 -35 582.0 0.18 0.83 86.82 1.40 1.70 0.46 -35 10.57 0.18 2.68 17.01 428.2 5.20 0.99 0.33 18.12 16.11 -35 0.87 2.14 0.38 16.15 126.8 0.62 37.81 0.93 1.15 -35 3.04 0.58 0.69 0.14 29.51 29.53 1.22 3.47 2.30 29.81 -35 0.33 1.17 5.91 23.66 0.16 0.83 3.38 65.06 0.08 3.05 3.45 1.13 2.50 3.45 0.21 2.62 53.27 1.54 4.07 0.72 0.35 0.46 11.86 8.27 0.95 0.43 11.66 1.00 6.85 0.57 6.80 2.52 0.26 0.62 30.62 0.30 2.10 3.06 1.47 2.00 25.61 4.39 1.08 1.85 0.07 0.65 4.92 2.41 0.22 0.66 2.77 4.48 5.07 0.07 1.35 1.27 0.20 0.19 1.30 1.71 0.39 1.54 1.57 0.49 1.53 0.47 0.64 0.54 0.81 3.70 0.84 3.62 0.40 2.28 2.39 2.26 2.74 Table 5. Table

39 OGS REPORT 297 Continued. Sample No.Method Sc ICP-OES ICP-OES V ICP-OES ICP-OES ICP-OES ICP-OES Y ICP-MS ICP-MS ICP-MS Zn ICP-MS ICP-MS ICP-MS Sr ICP-MS ICP-MS ICP-MS W La Ce Pr Nd Sm Eu Tb Gd Dy 93JAA-108693JAA-1090 14.2493JAA-1095 34.4093JAA-1096 102.0 35.1593JAA-1097 350.6 32.69 10.0793JAA-1100 226.7 21.65 31.2493JAA-1101 185.6 72.35 23.11 14.7793JAA-1101D 154.7 160.2 30.8593JAA-1102 7.81 193.4 394.7 31.84 134.193JAA-1104 8.02 263.7 79.40 10.06 -35 100.1 258.4 16.1893JAA-1106 193.6 41.11 -35 89.26 17.4693JAA-1107 16.16 62.62 12.24 17.54 100.9 22.43 -3593JAA-1108 10.28 252.6 88.24 33.97 111.3 35.37 13.28 -3593JAA-1109 110.5 154.2 494.3 2.01 26.72 9.96 17.86 -3593JAA-1111 4.12 193.5 99.12 68.63 0.46 -35 7.89 22.62 98.6793JAA-1112 5.08 3.89 111.0 93.64 1.06 15.16 10.37 -35 13.5593JAA-1113 13.36 204.1 1.42 -35 92.58 110.2 17.47 45.16 0.7793JAA-1114 91.21 117.0 2.69 2.87 3.53 4.23 93.51 32.04 45.20 -35 0.2593JAA-1114D 3.41 262.1 137.7 4.93 3.86 3.49 19.15 -35 0.87 0.4193JAA-1115 56.70 9.55 16.13 5.03 4.18 273.2 125.6 19.86 1.48 9.30 -35 1.65 16.8693JAA-1117 67.40 1.39 161.8 2.41 0.36 34.27 2.11 16.95 13.40 1.53 -35 56.95 159.9 19.65 7.1093JAA-1118 13.10 0.68 1.49 0.95 0.55 130.1 41.23 2.59 7.9693JAA-1119 6.74 7.85 4.20 115.5 0.76 3.48 7.50 1.98 -35 97.98 31.63 9.21 0.24 8.08 5.94 4.83 7.2593JAA-1121 0.36 238.8 91.68 1.96 -35 15.95 1.07 0.29 67.90 1.11 3.0893JAA-1122 2.36 4.57 0.41 4.93 4.28 -35 118.1 6.08 0.20 67.16 49.12 1.97 14.53 2.39 -35 17.1593JAA-1124 0.31 3.26 5.44 0.21 0.53 41.94 17.60 0.83 17.29 13.87 0.79 -35 1.16 77.20 1.35 1.04 2.55 17.31 0.84 104.5 1.80 78.64 28.87 0.93 1.04 -2 1.16 3.37 -35 1.88 0.51 79.62 1.45 4.20 4.08 2.43 0.21 15.17 3.45 -35 0.51 -2 5.22 6.18 103.7 104.0 1.44 3.18 0.44 0.15 49.01 0.68 0.53 3.05 1.40 -35 1.37 7.25 1.07 0.49 0.52 2.90 33.11 -2 0.88 -35 71.52 2.99 3.51 0.91 0.45 4.97 1.67 0.70 2.83 0.55 0.53 1.22 3.68 0.47 2.33 1.65 47.65 2.55 4.47 2.33 1.50 20.37 2.51 0.36 40.11 4.30 0.31 -35 0.32 0.17 1.46 5.84 0.71 0.31 -35 -35 1.60 6.64 3.11 0.13 4.37 84.57 0.17 1.73 1.85 -1 0.13 0.24 0.20 2.04 1.76 0.09 0.64 0.53 1.10 0.09 -35 2.30 -35 0.37 0.76 0.69 0.74 0.17 1.16 0.80 0.40 0.20 1.23 0.52 5.48 0.61 0.15 0.31 0.93 0.04 0.91 0.50 0.48 0.32 2.32 0.71 0.03 0.19 1.87 1.53 0.21 0.28 0.18 1.12 2.72 0.17 0.21 2.95 0.10 0.79 0.97 1.13 1.15 0.06 3.59 -0.07 0.13 1.17 -0.07 0.45 0.44 1.51 -0.03 0.45 0.29 0.71 1.60 -0.03 2.56 0.12 -0.02 0.46 0.98 0.15 -0.02 3.14 0.06 0.12 -0.03 0.12 0.04 0.08 0.66 0.04 0.60 0.06 0.99 0.20 0.79 0.31 0.19 Table 5. Table

40 NORTHERN SWAYZE GREENSTONE BELT ICP-MS ICP-MS ICP-MS ICP-MS ICP-MS Continued. Sample No.Method Ho ICP-MS Er ICP-MS ICP-MS ICP-MS ICP-MS Tm XRF Yb XRF Lu XRF Rb XRF Sr XRF XRF Nb XRF Cs Hf Ta Th Nb Zr Y Sr Rb 93JAA-100193JAA-1005 1.1193JAA-1006 0.91 3.0793JAA-1008 0.09 2.54 0.4793JAA-1014 0.68 0.24 0.3893JAA-1016 2.94 0.59 1.89 0.0493JAA-1020 2.34 0.97 0.43 1.64 0.2893JAA-1021 0.22 0.23 0.35 2.74 0.2593JAA-1027 2.04 1.77 0.58 0.04 0.63 0.4193JAA-1033 0.66 1.58 0.61 150.50 0.26 1.57 0.1093JAA-1035 4.37 2.61 0.47 0.24 1.75 0.22 67.9493JAA-1035D 3.44 4.37 0.61 0.26 129.55 0.37 1.29 0.2693JAA-1041 0.28 0.24 1.35 4.35 0.10 0.73 0.17 0.20 78.1793JAA-1042 1.61 -0.20 1.63 0.75 0.55 0.21 34.90 0.1193JAA-1043 1.25 0.05 1.16 0.93 2.14 1.08 0.11 0.23 1.39 0.08 55.7793JAA-1046 0.29 0.69 0.15 2.18 101.25 0.18 2.63 1.78 0.20 0.6693JAA-1055 0.28 0.18 0.28 0.34 0.12 3.62 190.47 0.11 0.42 0.3993JAA-1059 0.78 0.16 0.35 1.23 0.11 0.38 0.28 -10 147.93 0.91 0.67 -0.08 0.0693JAA-1062 0.31 0.25 5.82 2.55 0.50 0.19 0.98 0.31 1.37 -10 0.53 0.14 64.3593JAA-1068 4 1.91 0.38 -10 0.54 0.13 0.40 1.32 0.54 19.30 0.08 0.15 31.3593JAA-1069 0.84 0.35 0.15 5 1.52 31.29 0.40 0.06 1.43 -3 88 16.49 -10 0.04 0.1993JAA-1071 0.83 0.12 246.10 0.22 0.56 1.47 0.13 0.92 -10 0.2193JAA-1071D -0.08 85 1.17 0.30 0.54 29 1.23 11 0.14 167.30 3 0.35 0.13 0.35 -10 0.1593JAA-1078 0.14 2.02 0.28 0.08 0.36 1.38 25 141 -10 3 0.18 0.31 0.08 1.11 -5 0.0593JAA-1083 3.44 54 8.30 8.63 0.12 0.96 0.31 0.44 5 -10 2.91 0.23 0.40 35.05 0.04 21.00 6 -3 6493JAA-1085 118 53 0.32 0.46 0.11 0.38 22 0.05 -10 0.27 216.06 0.15 1.10 0.33 60.35 72 -0.08 -5 6 0.24 0.54 0.63 349.62 18 18 0.42 5 0.06 1.23 13.65 -10 0.18 -0.08 0.24 73 3 6.45 1.00 0.45 239.32 28 108 0.04 1.78 -10 0.17 0.12 34 5.43 0.41 0.03 8 1.06 0.04 -10 5 3 52.09 47 42.03 0.10 0.26 0.24 52 17 5.85 0.12 -3 -5 0.97 -10 41.05 88 1.41 0.17 0.37 -3 43 2.00 19 178 -5 0.84 1.67 -10 285.16 -0.08 2.41 0.92 0.14 23 27.80 -5 3 282.73 -0.08 2.48 23 14 137 -5 0.27 0.33 11.02 2.29 -10 4 3.79 0.48 3.91 9 591.70 53 3.78 -10 -5 0.37 62 8 1.98 0.20 460.19 -3 0.76 74 -10 1.06 30 0.38 17 4.96 -3 -5 1.07 -10 29 141.65 27 16 -0.08 5.84 0.10 -5 232 6 2.67 -10 2.85 22 -5 2.77 5 160 1.95 18 -5 -10 -0.08 142 0.53 0.28 7 12 2.84 134 18 0.28 0.30 -3 -10 12 9 1.05 165 -10 20 15 0.32 -10 194 -3 -5 32 0.30 17 0.36 -5 319 4 -10 3 8 11 228 16 0.13 33 127 -10 130 5 57 49 -5 -10 5 5 142 -5 15 -5 257 4 129 257 13 -5 38 14 53 36 570 420 28 19 12 132 -5 Table 5. Table

41 OGS REPORT 297 Continued. Sample No.Method Ho ICP-MS Er ICP-MS ICP-MS ICP-MS Tm ICP-MS XRF Yb XRF Lu XRF Rb XRF Sr XRF Nb XRF XRF Cs ICP-MS ICP-MS ICP-MS ICP-MS ICP-MS Hf Ta Th Nb Zr Y Sr Rb 93JAA-108693JAA-1090 0.3993JAA-1095 1.31 1.0493JAA-1096 0.59 3.41 0.1593JAA-1097 0.33 1.67 0.5193JAA-1100 0.88 0.33 0.89 0.2593JAA-1101 3.12 0.68 0.13 0.89 0.1493JAA-1101D 1.56 0.87 0.45 1.78 0.1493JAA-1102 0.79 25.76 0.90 0.23 2.21 0.2793JAA-1104 1.38 0.87 2.04 0.50 408.49 0.13 0.3393JAA-1106 64.54 1.71 0.72 0.32 0.14 1.34 87.1293JAA-1107 3.26 0.47 1.97 0.93 207.88 0.26 1.96 0.18 2.0193JAA-1108 28.13 0.51 6.71 0.73 0.30 2.46 0.30 12.7293JAA-1109 1.23 13.09 1.11 0.29 0.21 95.16 1.43 0.3593JAA-1111 0.22 0.70 1.86 1.01 0.16 504.77 0.44 1.65 0.14 0.61 0.21 0.7393JAA-1112 0.64 2.09 0.25 108.85 0.28 0.48 1.40 0.09 0.2993JAA-1113 8.77 28.17 0.11 1.38 107.56 0.52 0.67 0.27 0.66 0.60 0.0793JAA-1114 2.61 3.11 0.53 0.83 -10 205.67 0.40 4.55 0.21 1.96 0.39 0.10 3.04 0.0893JAA-1114D 4.42 0.45 0.35 0.35 0.09 2.30 -10 0.41 0.31 96.1293JAA-1115 0.35 5 7.50 -0.08 0.99 0.66 1.46 -10 0.41 138.16 0.06 0.98 0.3793JAA-1117 -0.08 1.14 1.78 0.97 110 0.22 7 2.05 0.63 2.91 126.60 0.10 -10 0.15 0.4193JAA-1118 3 0.60 4.39 0.68 2.35 0.70 -10 0.15 0.26 0.63 12 13793JAA-1119 0.19 7.64 0.19 -3 1.34 1.92 0.92 1.22 0.02 -10 45 0.38 1.93 0.19 0.10 0.11 0.92 -393JAA-1121 391 8.44 38 0.14 0.01 -10 0.15 0.05 22 0.35 0.47 0.04 0.29 0.5393JAA-1122 18 8 19.96 9.87 26 -10 0.57 0.14 0.24 26 -0.05 1.65 80 0.25 0.0193JAA-1124 96.2 198 3 3.05 1.79 0.06 0.39 9 -10 0.18 0.32 90 0.09 0.74 0.01 0.70 10 3 3.06 123 -5 0.29 0.05 0.54 0.27 63 0.27 0.19 1.65 67 15 -10 19.19 0.11 -0.03 19 7 0.32 0.08 0.94 1.64 86 66 -0.02 19.70 -10 0.08 2.2 0.03 0.31 -0.02 22 467 -5 0.80 0.76 144 -3 0.03 -0.08 0.55 -10 27 24 0.47 0.46 0.15 15.8 0.55 8 0.17 -0.08 0.22 12 -0.09 0.13 111.63 98 15 53 -10 0.35 -3 0.70 0.07 98 -0.08 158 0.03 0.37 0.71 -10 193 2.99 0.94 5 2.08 0.27 22 -2.00 -3 0.12 0.75 36 -5 0.52 -10 28 26 0.10 0.50 -3 -0.20 0.55 0.13 -0.20 91 0.09 18 91.81 15 -10 21.1 131 -0.08 -3 -0.02 -0.08 -2.00 14 0.35 -0.02 -10 120 5 0.41 -5 8 -10 3 0.39 0.30 24 -10 -0.20 -0.08 6 -0.1 5 3 -0.1 0.13 -3 44 9 0.34 0.04 8 -10 3 0.02 -0.08 10 -0.08 59 -10 19 -5 23 0.37 0.24 11 -3 -5 -10 25 -0.1 24 -10 89 3 9 -5 -0.08 -0.08 11 18 -3 120 -0.08 -3 -5 50 19 -10 20 18 -10 8 -10 8 7 20 -5 -3 5 16 -3 -3 -5 104 -5 18 -5 18 10 -5 -5 -5 8 -5 -5 6 -5 21 84 -5 -5 -5 -5 Table 5. Table Negative numbers indicate that the content is below detection limit of analytical method used.

42 NORTHERN SWAYZE GREENSTONE BELT Structural Geology

KAPUSKASING STRUCTURAL ZONE faulting. Those designated S1, S2 and S3 are interpreted to be associated with early, regional-scale folding; S4 and S5 Eight generations of deformation are recognized in the are interpreted to be related to late ductile deformation. Kapuskasing Structural Zone (Bursnall 1989), and are The 2 earliest generations of penetrative fabric are herein designated D1 through D8. They include early D1 to roughly parallel to the orientation of the units, and each D4 ductile structures and late D5 to D8 ductile-brittle, fault- other, throughout much of the NSGB. Rarely, early F1 iso- related structures. In the KSZ within the map area, D1 gneissosities mainly strike northeast with moderate dips to clinal folds and a penetrative, axial-planar S1 cleavage the northwest, but are also locally easterly trending, with were observed as refolded folds in tight to isoclinal F2 moderate northerly dips suggesting folding. Observed out- folds. Because the axial planar S2 foliation is subparallel to crop-scale isoclinal folds have shallow plunges to the S1 (with the rare exception of the fold closures), it is there- southwest. The map-scale variations in the trend of gneis- fore difficult to distinguish the S1 and S2 fabrics without sosity from northeast to east are probably the result of the presence of overprinting relationships. As the S1 and S2 folds are both isoclinal, it is assumed that the associated large-scale D3 folds with shallow westerly or northwesterly plunges. The variation in the trend of gneissosity may have deformation resulted in a large amount of regional short- been influenced by the uplift of the KSZ accompanied by ening and transposition. It is, therefore, difficult to deter- some dextral displacement, rotating gneissosities near the mine what the original orientations of F1 structures may cataclastic zone into Z-shaped asymmetry. Lineations in have been because of large-scale transposition into the the monzonite gneiss of the Ivanhoe Lake cataclastic zone generally easterly trend of F2 structures. The S1 foliation or also suggest dextral offset, as they are oriented obliquely cleavage is evident in many outcrops as a penetrative flat- to the dip of cataclastic foliation, rather than downdip tening fabric. The S2 fabric is evident as a variably developed, (i.e., plunging west rather than northwest). steeply dipping penetrative foliation to a spaced cleavage, generally subparallel to the S1 fabric. The S3 fabric is a Two northwest-trending late faults are associated with steeply dipping, spaced axial-planar cleavage associated the KSZ in the map area. The western fault lies along the with southeast-trending open folds overprinting S1 and S2, eastern margin of the Shawmere anorthosite complex and and is most evident in the southeastern part of the NSGB. was previously recognized by Riccio (1981). It is characterized by numerous “veinlets” of black, aphanitic pseudo- Lineations within the map area range from steep to tachylite and mylonite. These cataclastic zones range up to shallow in plunge. Lineations which mark the intersections several centimetres thick, and are extremely variable in of cleavages and/or bedding planes predominate. However, orientation, crosscutting the earlier gneissosity. The east- only the stretch lineations which measure the elongation of ern fault has been identified as the Ivanhoe Lake cataclastic clasts or minerals were recorded on Map 2627 (back pocket). zone and is considered to be the boundary between the The highly variable orientations of minor fold axes and lin- KSZ and the Abitibi Subprovince (Percival 1990). On a eations is attributed to later refolding episodes. regional scale, it is characterized by a zone of cataclasis up to 1 km wide, marked by positive aeromagnetic anom- The S4 and S5 fabrics are only observed in highly alies, paired gravity anomalies with a low centred over the schistose rocks proximal to shear zones and are thus inter- zone, and a broad zone of subsurface reflectors detected preted to be associated with late ductile deformation. The on seismic surveys that dip at about 35¡ to the northwest S4 fabric consists of a steep, northeasterly trending spaced (Percival 1990). In the map area, the Ivanhoe Lake cata- cleavage, axial planar to open Z-folds and northeast-trending clastic zone is characterized by augen-textured monzonite Z-shaped kink bands. The S5 fabric is a gently dipping, gneiss, exposed along Highway 101 and the old channel pervasive crenulation or kink cleavage with northwest to of the Ivanhoe River north of Highway 101. The mon- northeast strike orientations that are axial planar to gently zonite gneiss has shallow, west-plunging stretching lin- plunging open folds to locally tight chevron folds. As eations and gently plunging folds in the plane of foliation, overprinting relationships are uncommon and difficult to with asymmetry indicating a west-side-up displacement interpret, it is possible that the chronology of S4 and S5 may be reversed. along the cataclastic zone.

NORTH SWAYZE GREENSTONE Folding BELT ZONE A number of fold axes are indicated on Map 2627 (back pocket) with their interpreted generation. The locations are Five generations of tectonically induced fabric were based on reversals of top indicators or systematic changes observed within the NSGB, indicating that a number of in the orientation of primary structures and/or foliations. distinct episodes of deformation have affected the belt in a In the southern part of the Swayze greenstone belt, complex interplay of polyphase folding, transposition and Heather (1993) was able to differentiate 2 early fabrics

43 OGS REPORT 297

into an Sa schistosity, that is tightly to isoclinally folded east-trending F2 isoclinal folds and are overprinted by about a west- to west-southwest striking foliation, des- southeast-trending, open F3 folds. In the same area, the ignated Sb. It would seem that a similar manifestation large-scale “Z” fold in the Nat River iron formation and orientation of early folding fabrics in the northern (Map 2627, back pocket) has the wrong vergence to be Swayze greenstone belt are likely to have been generated a drag fold associated with the Nat River anticline, and synchronously with those in the southern part of the belt. is thus interpreted to be an F1 isoclinal fold unrelated to the main structure. Although sparsely distributed, top indicators uniformly indicate a southward younging direction in the northern The distribution of the northern ultramafic unit in part of the NSGB, from the Nat River granitoid complex the HNA is more continuous and modified by folding to the main sedimentary unit. East-plunging minor folds than was interpreted by Milne (1972). This reinterpretation and a number of reversals in younging direction were is based on the field evidence for multiple-folding observed in sedimentary bedding in the vicinity of the events, the outcrop distribution and the high resolution southern part of Slate Rock Lake, in Keith Township. aeromagnetic patterns in this area. The new interpretation Coaxially refolded, thinly bedded sedimentary rocks in indicates the unit is isoclinally folded in an easterly this area and other parts of the map area indicate that at trending F2 (or possibly F1?) antiform and refolded on least 2 early regional folding episodes have affected the the southern limb by southeast-trending F3 folds, north of area. The interpretation of the pattern of reversals sug- Chabot Lake. gests an east-trending F2 fold in the southern part of Slate Rock Lake may have refolded an F1 fold axis, In the vicinity of the ultramafic to gabbroic unit hosting north and south of the F2 axis. Younging reversals, sug- the Reeves and Penhorwood mines the trends of S1 and S2 gesting anticlinal and synclinal closures, also occur in a change from predominantly easterly to northerly. The S1 band of predominantly volcanic rocks extending up to fabric follows the trend of the basal contact of the ultra- several kilometres south of the main sedimentary unit in mafic cumulate unit around the northern nose of the fold, northern Keith Township. From the Kukatush pluton to thus suggesting the ultramafic unit is tightly folded about the MacKeith Lake fault, the observed younging direc- a north-trending F2 axis, with the gabbroic unit occupying tion is consistently to the north. These features suggest that the core of the F2 antiformal syncline (Map 2627, back the main sedimentary unit in the northern part of Keith pocket). Easterly flexures and/or offsets in the F2 fold axis and Penhorwood townships lies in the keel of a syncli- and rock unit contacts are the result of overprinting by norial fold and thus in the uppermost stratigraphic part early ductile deformation zones of the D4 to D5 generation of the MuskegoÐReeves assemblage. (discussed below). The presence of talc-chlorite schists along the northwestern margin of the ultramafic unit suggests

Coaxial refolding of F1 by F2 was also observed in that the contact follows an early (D1 or D2), northeast- minor folds in the Radio Hill iron formation and is most trending ductile deformation zone. The presence of this likely the reason for the extensive thickening of the iron shear zone may also indicate that the abrupt truncation of formation in the vicinity of Radio Hill, in Penhorwood the clastic sedimentary unit along the western margin of Township. Milne (1972) reports a possible synclinal the ultramafic body is the result of early faulting. (F1?) fold that causes the iron formation to bifurcate west of Leadbeater Lake and end abruptly (close) east of A southeast-trending F2 antiform and synform are Radio Hill. He also indicates the iron formation is folded interpreted in amphibolitic mafic volcanic rocks in into an isoclinal S-shaped fold (F2?), plunging 50¡ to the southeastern Ivanhoe Township, based on changes in the northwest in the vicinity of Radio Hill. orientation of S1 foliations (Ayer 1993).

The Nat River iron formation lies at the boundary of the MRA and HNA and delineates a northwest-plunging, Faulting east-trending anticlinal structure (see Figure 2). Both limbs of the fold dip steeply to the north and thus define an isocline steeply overturned to the south. Top indica- Fault locations are commonly based on the interpreta- tors uniformly indicate north facings on the north limb, tion of geophysical patterns or offset of rock units, suggesting that the fold is an F1 anticline, but there is because of poor exposure. At least 3 distinct generations insufficient exposure in the closure area, in the western of faulting are evident in the NSGB, but determining the part of the structure, to distinguish it from a possible F2 detailed chronology awaits more detailed structural anticlinal antiform. The map pattern of iron formation work and high-precision geochronology. The earliest repetition on the north limb in the vicinity of the east generation of faulting is in the widespread ductile defor- branch of the Nat River, and south of Crawford Lake, mation zones. The early faults are locally truncated by suggests “S” and “Z” drag folds, respectively, that may less extensive brittle-ductile faults. Thirdly, the latest be genetically related to the main antiformal (F2) fold. generation are brittle faults which do not appear to have Minor folds in outcrops east of the Crawford River, on any significant ductile deformation but are not well the north limb, indicate that F1 isoclines are refolded by exposed.

44 NORTHERN SWAYZE GREENSTONE BELT

DUCTILE FAULTS separate fabrics are also evident in the shear zones associated with the Joburke Mine but, in contrast to the SRDZ, the The early deformation zones are generally easterly trending, flat S5 crenulation cleavage is only locally developed, parallel to the contacts of rock units and are gradational whereas the steeply dipping S4 fabric is a pervasive axial- from the moderately foliated and relatively unaltered planar cleavage to northeast trending Z-folds. It has been country rock into the highly deformed, carbonatized, suggested (Milne 1972; Jackson and Fyon 1991) that the sericitized and chloritized schistose rocks whose protolith PorcupineÐDestor fault may strike southwest into the is often difficult to determine. Intense deformation and NSGB. If this is so, it is probable that these numerous east- alteration commonly occur in zones 10 m to 1 km wide, northeasterly trending ductile deformation zones represent which anastomose around blocks of less deformed and the extension of this major structure into the map area. altered rock. The most extensive early ductile faulting is associated with the Slate Rock deformation zone (SRDZ) and is well exposed in southern Muskego and Reeves BRITTLE-DUCTILE FAULTS townships. The SRDZ is an extensive zone of ductile deformation up to 1.5 km wide, extending eastward across The MacKeith fault represents a later generation of brittle- the southern part of Muskego Township. It extends west- ductile faulting. The fault trends east-northeast across ward into Foleyet Township, but poor exposure in this area much of Keith Township. Where it is well exposed, in the results in a higher degree of uncertainty about its location vicinity of the Joburke Mine, it consists of schistose, brec- and extent. To the east, in Reeves and Sewell townships, it ciated and hematitized rock in a zone up to 50 m wide appears to break up into a larger number of parallel zones which clearly truncates a number of east-southeast-trending which are, individually, narrower than the broad zone in rock units and the earlier Joburke deformation zone. The southern Muskego Township. western and eastern extensions of the fault are more spec- ulative, but based on airborne geophysical evidence, the Three separate fabrics are evident in the schistose fault appears to be truncated by the Hoodoo Lake pluton in rocks throughout much of the SRDZ. The early fabric con- the east. sists of a subvertical, east-trending pervasive schistosity (S1 or S2), which is interpreted to have formed during D1 or The Muskego fault is an east-trending deformation D2 deformation. It is overprinted by a northeast-trending, zone along strike with the MacKeith fault, on the west side steeply dipping spaced cleavage (S4) which is axial planar of the Hoodoo Lake pluton in Ivanhoe Township. It is only to upright Z-folds and a spaced cleavage (S5) with subhor- exposed in a few small outcrops where it consists of east- izontal dips and variable orientations. Small-amplitude trending, foliated, carbonatized and epidotized rocks that crenulation and chevron folds associated with S5 are sub- contain radiating sprays of recrystallized amphibole. horizontal and indicate late north-side-up movement in the Based on aeromagnetic patterns, the fault abruptly truncates SRDZ. an ultramafic volcanic unit. It is also the locus of an abrupt transition from greenschist-facies rocks north of the fault The Deerfoot deformation zone (DDZ) is another to amphibolite-facies units south of the fault (Ayer 1993). extensive deformation zone which extends from north of This transition indicates that higher metamorphic condi- the Kukatush pluton in Penhorwood Township to north of tions were experienced in rocks south of the fault and the HNA in Kenogaming Township. An abrupt change hence a net south-side-up displacement. from southward younging stratigraphy north of the DDZ to northward younging south of the zone suggests the pos- sibility that the younging reversal may be the result of thrusting along the fault rather than a regional syncline. BRITTLE FAULTS

The Hardiman deformation zone (HDZ) extends into Northerly trending faults are indicated on Map 2627 (back the map area from the south, and joins with the DDZ along pocket) where they have been interpreted on the basis of the north boundary of the HNA. The HDZ develops into abrupt truncation or offset of rock units. These structures several parallel faults in southwestern Penhorwood are most likely high-crustal-level brittle faults which are Township that dip moderately to the northwest. These delineated by lineaments but are not commonly manifest faults are the locus of a number of commercially devel- in outcrop. Although most evident in the eastern part of the oped veins of quartz and barite that occur along the faulted map area, they probably occur throughout the region and southeastern margins of thin granitic intrusions. In this were most likely the conduits for the numerous vicinity, shear banding indicates late dip-slip movement, Matachewan diabase dikes. Thus, they are bracketed in with a relative southeast-side-up displacement. maximum age by the Matachewan diabase dike crystallization age of 2454 Ma. The minimum age is given by Many of the deformation zones are locally auriferous offsetting of the east-northeast-trending Abitibi swarm and have been the focus of gold exploration, such as at dikes with a crystallization age of 1140 Ma. This suggests the Joburke Mine in the Joburke deformation zone. Three a protracted Proterozoic history.

45 OGS REPORT 297 Economic Geology

There are records of exploration activity in the area that 1) widespread early mineralization with relatively low date back to the end of the 19th century (Milne 1972). The grades, which occurs in thin quartz-carbonate veins that area has attracted considerable exploration attention parallel the S1 foliation in highly schistose and carbonatized because of its apparent continuity with the economically basalts within the Joburke deformation zones; and 2) con- prolific Abitibi greenstone belt to the east. Gold, base centrated in late quartz veins and stringers which crosscut metals, iron, and industrial minerals such as asbestos, the S1 foliation. The 4 developed Joburke ore zones occur talc, silica and barite have been the focus of attention; where these late vein systems are thickened by folding mines have been established and undeveloped deposits into steep, easterly plunging, S-shaped fold noses. The have been found containing a number of these commodities. MacKeith Lake fault apparently truncates the Joburke Significant amounts of asbestos and gold have come from deformation zones west of the mine and, despite exten- the Reeves Mine and the Joburke Mine, respectively. sive diamond drilling, appears to host only minor gold Production has also been recorded at the Cryderman mineralization. barite, Horwood silica and Roseval silica deposits. The Penhorwood talc mine is the only actively producing Gold is locally present in other deformation zones, deposit at the time of writing. some of them minor and unnamed. Others are of major extent, such as the Slate Rock Lake deformation zone in A significant amount of exploration has been con- southern Muskego Township, and the Deerfoot deforma- ducted in the area, the details of which are not covered tion zone, which may be the easterly strike extension of here. For more detailed information on exploration, the the Joburke deformation zone. reader should consult 1) the assessment files in the Resident Geologist’s office, Timmins; 2) assessment data in the Arkell (3) Earth Resource and Land Information System, in Sudbury and Toronto; 3) previous geological reports of the area Gold mineralization occurs in a north-trending fault in (e.g., Prest 1951; Milne 1972; Ayer 1993; Ayer, in press); mafic metavolcanic rocks infilled by irregular masses of or a mineral inventory report available in hard copy (Fumer- quartz, in southwestern Sewell Township. Tanton (1917) ton and Houle 1993) and digital copy (Fumerton et al. 1993). reports that the vein material mixed with country rock locally reaches up to 15 m in width. Three pits were exca- In the following section, localities in which there has vated on the vein, which was traced for a strike length of been mineral production or notable grades and quantities 800 m. Minerals reportedly associated with the quartz are of mineralization are briefly discussed. They are grouped pyrite, pyrrhotite, chalcopyrite, calcite, tourmaline and by their principal commodities and discussed in alphabetic “mariposite” (fuchsite?). Tanton (1917) reported assay order. The numbers in parentheses in the heading for each results from grab samples of up to 0.7 ounce Au per ton, locality correspond to those appearing on Map 2627 (back and chip samples of 0.02 ounce Au per ton across the pocket). Their names are based on geographic location, width of the vein. name of the discoverer, or the company which conducted the exploration resulting in the discovery, and are not BHP-Utah Mines Limited (4) meant to reflect current ownership. No formal title searches have been conducted as a part of this study. From 1985 to 1989, BHP-Utah Mines covered the southeastern part of Muskego Township with ground magne- GOLD tometer, electromagnetic (EM), induced polarization (IP), and geochemical surveys, stripping, trenching and diamond- Gold mineralization occurs in epigenetic vein systems in drilled 20 holes. Surface samples assayed up to 3700 ppb close spatial association with ductile deformation zones. Au southeast of Big Boulder Lake. Slightly auriferous It occurs in a wide variety of rock types, but is most com- zones were detected in a number of the drill holes, with monly associated with rusty weathering and schistose, assay values up to 1030 ppb Au over 0.3 m. Anomalous iron carbonatized and/or sericitized, mafic volcanic rocks. values of zinc in disseminated sulphides within schistose The mineralization is closely associated with quartz- volcanic rocks were also detected in 2 of the drill holes. carbonate veining, commonly with disseminated iron sulphides, and locally with arsenopyrite, stibnite and base B.P. Resources Limited (5) metal sulphides. Tourmaline and green mica may also be present. B.P. Resources Limited explored for gold on a claim group in south-central Muskego Township and north-central Keith Gold was found in sufficient quantities and grade at Township from 1987 to 1989. Work consisted of airborne the Joburke Mine, in Keith Township, to have supported and ground magnetic, EM and IP surveys, a geological the production of almost 1/2 million tons of ore with an survey and diamond drilling. Two holes were drilled in average grade of 0.11 ounce Au per ton. The gold miner- Keith Township. One of these drill holes, on the east side alization at the Joburke Mine occurs in 2 structural settings: of Slate Rock Lake, encountered a number of auriferous

46 NORTHERN SWAYZE GREENSTONE BELT intersections associated with intrusive porphyry phases. Mineralization similar to that at the Joburke Mine was dis- Assay results range from 0.01 to 0.04 ounce Au per ton covered. From 1985 to 1989, G.K. Sanford, Gail over 10 to 15 m sections, with gold associated with minor Resources Limited and finally Marshall Minerals pyrite in thin chloritic fractures. In Muskego Township, 9 Corporation conducted airborne and ground magnetometer holes were diamond drilled in the area bounded by Keith and EM surveys, an IP survey, geological mapping, stripping, Lake to the east, Slate Rock Lake to the west and Scorch trenching and diamond drilling. A program of extensive Creek to the north. One hole, about 1 km west of Keith overburden removal and limited surface mining for bulk Lake, intersected 4.8 m of auriferous quartz veins in inter- sampling was undertaken in the vicinity of the Hoodoo mediate volcanic rocks with assay values of up to 0.011 and Patricia showings. The stripping uncovered a large ounce Au per ton over 1.3 m. A second hole, about 500 m area of outcrop around the showing which was mapped in east of Slate Rock Lake, intersected 12 m of auriferous detail by Siragusa (1990). carbonatized wacke. The wacke contains up to 5% disseminated pyrite and is cut by quartz-carbonate veins. Results of work on this claim group by Marshall Assays from this section are slightly anomalous, with values Minerals Corporation, as summarized from Medd (1990), of up to 0.027 ounce Au per ton over 1.5 m. indicate the gold mineralization occurs in a south-southeast-trending shear zone within carbonatized mafic volcanic rocks cut by abundant intermediate porphyry dikes. Bromley (6) The Patricia zone occurs at the northeast end of the out- The Bromley occurrence is located in northwestern crop area exposed by the stripping program. Gold values Penhorwood Township. Radio Hill Mines Company have been intersected in a mineralized zone which pinches Limited performed a considerable amount of exploration and swells from 3 to 49 m over a strike length of 158 m in 1967, including an airborne EM survey, mapping, and to a depth of 184 m. The mineralized zone consists of trenching and diamond drilling. A number of mineralized quartz-carbonate veining with disseminated pyrite and quartz veins and stockworks were outlined in pervasively rarely chalcopyrite and galena. Erratic gold values as high carbonatized and sheared mafic volcanic rocks cut by as 0.528 ounce Au per ton over 1.2 m occur over narrow tonalite dikes. Silver-bearing sulphides, including argen- lenses of pyritic quartz-carbonate vein, separated by non- tite and galena, have been reported. Assay values of auriferous, less-altered host rock. The Hoodoo west showing 0.13 ounce Au per ton and 3 ounces Ag per ton over 0.6 m is a 0.15 to 1.5 m wide vein extending for a distance of (2 feet) were reported from diamond drilling. Another about 61 m in the north-central part of the stripped area. showing, known as the RF zone, occurs north of the main The vein system has been sampled every 4.6 m and carries showing on the west side of Primer Lake. Samples from an average grade of 0.15 ounce Au per ton over a width of trenching on this showing returned values of up to 15 ounces 1.2 m. The Hoodoo east showing is a quartz-carbonate- Au per ton and 23 ounces Ag per ton, but typically were pyrite vein hosted in a north-northeasterly trending cross- much lower (Fumerton and Houle 1993). fracture in the eastern part of the stripped area. This vein returned values of 0.072 ounce Au per ton over 0.7 m, In 1989, American Barrick Limited intersected anom- 0.152 ounce Au per ton over 0.6 m and up to 4.03 ounces alous gold values in a drill hole testing a geophysical Au per ton in grab sample. The drilling in this area only anomaly about 1 km southeast of the main showing. Assay intersected low-grade material (0.03 ounce Au per ton over results reported up to 0.60 g/t Au over 1 m (Fumerton and 7 m with values of up to 0.18 ounce Au per ton over 0.6 m). Houle 1993). A second area of gold mineralization was outlined by stripping, trenching and diamond drilling, about 1 km Card Lake Copper Mines Limited (7) northeast of the HoodooÐPatricia prospect. The mineralized zones consist of quartz-carbonate veinlets and lenses In 1971 and 1972, Card Lake Copper Mines Limited carried 0.3 to 1.5 m (1 to 5 feet) wide, with pyrite and minor chal- out a magnetic and EM survey and diamond drilling copyrite and galena. The host rocks are felsic volcanic focussed on a stibnite showing in southwestern Sewell rocks with a pervasive east-northeast-trending high-strain Township. The mineralization occurs in a 2 m wide, south- zone consisting of narrow anastomosing zones of sericitic east-trending shear zone within moderately strained, mafic schist surrounding lenticular blocks of more massive felsic pillow lavas immediately east of a northwest-trending rock. Drilling indicated values of up to 0.161 ounce Au per diabase dike. Quartz veinlets and the schistose mafic rock ton over 1.8 m (Medd 1990). of the shear zone have variable concentrations of disseminated stibnite, arsenopyrite, pyrrhotite, pyrite and chalcopyrite. Assay values indicated up to 1.8 ounces Au per ton, Joburke Mine (15) 7.4% Sb and 2.1% As. The Joburke Mine property consists of a block of 20 patented claims in Keith Township. The property is cur- Hoodoo-Patricia (10) rently held by Noranda Exploration Company Limited in a joint venture negotiated with Tarzan Gold Incorporated From 1946 to 1947, Dunvegan Mines Limited (formerly in 1988. Gold was discovered in 1946 by Joe Burke and Hoodoo Lake Mines Limited) explored a claim group Maynard Bromby. Underground work by Joburke Mines southeast of the Joburke Mine in Keith Township. Limited was started in July 1947 and continued until

47 OGS REPORT 297

August 1948. Approximately 132 diamond-drill holes greater than 915 m was suggested by Prest (1951) based totalling 39 000 feet were drilled (Neelands 1988). A on the interpreted dislocation of units. He also suggested three-compartment shaft was sunk on the Main Zone to a however, that this represented the horizontal vector of a depth of 408 feet. Levels were established at the 250- and larger, but unmeasurable, vertical displacement. 375-foot levels and 2714 feet of lateral work was completed. This work showed the existence of 2 gold-bearing Gold mineralization is mainly confined to zones up to zones: the Main Zone, on which all the underground work about 30 m thick, consisting of intense ductile deformation was focussed at this time, and the North Zone, located with accompanying pervasive iron-carbonate alteration about 400 feet northwest of the Main Zone. From this and localized quartz veining, within the north and south work, possible ore reserves in the Main Zone were esti- arms of the Joburke deformation zones. Mineralization mated at 130 464 tons averaging 0.268 ounce Au per ton within these deformation zones is of 2 distinct styles. The (Neelands 1988). first consists of widespread mineralization with relatively low grades and occurs in thin quartz-carbonate veins In 1964, Denison Mines Limited diamond-drilled 6 which parallel the S1 foliation. These early veins are com- holes totalling about 5000 feet, searching for downdip monly folded in conjunction with the S1 foliation into extensions to the east and west parts of the Main Zone westerly plunging Z folds with a steeply dipping, north- mineralization. east-trending axial-planar S2 cleavage. The second consists of thicker and higher grade extensional quartz veins Noranda Exploration Company Limited optioned the or intricate networks of quartz stringers and veins which property in 1973. Mining operations were restricted to the east are found in variously silicified, albitized and carbonatized and west parts of the Main Zone via a decline extending to mafic volcanic rocks. The vein material is largely quartz, the 250-foot level. From 1973 to 1975, a total of 180 300 tons albite and carbonate with a minor amount of chalcopyrite grading 0.105 ounce Au per ton was trucked to the Pamour and rarely visible gold (Prest 1951). The mined ore zones Mill in Timmins. Prior to these mining operations, are typically confined to locations where these higher grade Noranda had estimated a possible reserve of 381400 tons veins are thickened by steeply east-plunging S-shaped of 0.21 ounce Au per ton. The resulting low grades may folds (Prest 1951). have been caused by the erratic nature of the gold mineralization within a wide alteration zone of quartz-ankerite. In 1979, the decline was extended to its ultimate depth Johnson Wright (16) of 489 feet. Total production from 1979 to 1981 was 291795 tons grading 0.106 ounce Au per ton. The bulk of this was derived from the Main Zone. Near-surface miner- The Johnson Wright occurrence is located in southwestern alization was also mined at the North Zone and the Sewell Township. It has undergone exploration including Northwest Pit, a small zone about 1300 feet west of the geophysical surveys, stripping, trenching and diamond shaft area. A total of 21374 tons grading 0.082 ounce Au drilling. The mineralization occurs in quartz-carbonate per ton was derived from North Zone and 1209 tons grading veins, with pyrite, tourmaline, and minor chalcopyrite and 0.063 ounce Au per ton from the Northwest Pit. galena, in sheared and carbonatized mafic volcanic rocks. Exploration on the property was reactivated from 1988 to The best reported assays of 15 g/t Au and 3.7 g/t Au were 1989 with geological, magnetic, EM and IP surveys, strip- from trench samples collected by Glen Auden Resources ping, trenching, sampling and diamond drilling. Limited in 1987. The mineralization occurs in parallel 2 to 25 cm quartz veins spaced 2 to 3 m apart in iron-carbonatized, schistose mafic volcanic rocks exhibiting a southeast- The property is underlain by compositionally diverse trending schistosity. Individual veins are up to 10 m long volcanic rocks which include mafic volcanic flows, por- and alteration zones are up to 100 m long. phyritic felsic pyroclastic rocks, flows and/or synvolcanic intrusions and ultramafic flows. Interbedded sedimentary rocks include magnetite-chert and siderite-chert iron formation, turbidites normally graded from conglomerate Jonsmith (17) or sandstone to siltstone, and graphitic mudstones. Rock units dip steeply to the north, and strike northeast north of Mineralization at the Jonsmith occurrence in central the MacKeith Lake fault and southeast south of the fault. Kenogaming Township occurs within schistose felsic vol- All observed top indicators indicate that the stratigraphy canic rocks of the HNA. It consists of pyritic, sericitized faces consistently to the north. The MacKeith Lake fault and silicified fragmental rocks with thin sphalerite (or Joburke fault, Prest 1951) strikes 075¡ and dips 60¡ to stringers locally cut by quartz veins containing pyrite and 75¡ to the north. The fault zone contains brecciated frag- chalcopyrite. Diamond drilling by Falconbridge Mines ments of chert, iron formation, lamprophyre dike and talc- Limited in 1966 returned assay values of up to 1.21% Zn, chlorite schist. Rocks south of the MacKeith Lake fault 0.51 ounce Ag per ton and 0.03 ounce Au per ton over 1.1 m, generally appear to have experienced greater amounts of and 1.03% Zn, 0.55 ounce Ag per ton and 0.01 ounce Au ductile strain than those north of the fault. A significant per ton over 4.3 m. It is interesting to conjecture as to the amount of dislocation along the fault is suggested by the origin and significance of the mineralization at this occur- change in strike orientation and the abrupt truncation of a rence and it is probably worthy of further study. The dis- number of rock units. A net sinistral displacement of seminated nature, associated rock types and alteration

48 NORTHERN SWAYZE GREENSTONE BELT might indicate that the mineralization is of a volcanogenic is parallel in trend, and may be a subsidiary structure to the massive sulphide type modified by later deformation, or more extensive Deerfoot deformation zone located several alternatively, the mineralization could be epigenetic and hundred metres to the south. The main vein consists of related to the deformation. milky quartz and minor calcite cut by fractures infilled with pyrite and minor chalcopyrite. Reported assay values from diamond drilling range up to 0.48 ounce Au per ton Kalbrook (18) over 2.2 m and 0.28 ounce Au per ton over 2.3 m, in 2 separate holes. This gold occurrence in southeastern Reeves Township has undergone a considerable amount of exploration including geophysical and soil geochemical surveys, strip- Nib Yellowknife (25) ping, trenching and diamond drilling, dating back to Kalbrook Mining in 1946. Late quartz veins with visible gold and disseminated pyrite crosscut sheared mafic vol- The Nib Yellowknife occurrence, located in north-central canic rocks with minor interbedded clastic sedimentary Penhorwood Township, has been explored since the mid rocks. A number of bands of intense east-trending shearing 1940s. Work done includes stripping, trenching, geophysical are separated by relatively undeformed zones. In one surveys, and a limited diamond-drilling program by locality, isoclinally folded schistose and altered units are Steetley Industries Limited in 1987. The mineralization cut by an auriferous quartz vein which is discordant to the occurs in quartz veins with disseminated pyrite and early foliation and is only slightly folded (Fumerton and arsenopyrite within a gabbroic unit on the western margin Houle 1993). The auriferous veins (2 to 20 cm wide) are of the ultramafic body hosting the Reeves and zoned, with between 2 and 5 cm of grey, coarse-grained Penhorwood mines. Reported grab sample assay values quartz along the walls, and white, very coarse-grained are up to 0.2 ounce Au per ton. quartz in the central part of the vein. Pyrite is erratically disseminated within the veins and locally is concentrated in the wallrock. Rare chalcopyrite has also been observed. Tremblay (32) Gold occurs as fine specks along fracture surfaces within the white quartz. Chip samples of a quartz vein in a trench returned up to 38.89 g/t Au from sampling by Glen Auden This showing, in southwestern Sewell Township, has been Resources Limited in 1987. Parallel chip sampling by explored by geophysical surveys, a lithogeochemical sur- Fumerton and Houle (1993) returned up to 7.68 g/t Au. vey, geological mapping, trenching and diamond drilling since 1972. American Barrick Resources Limited carried out a surface sampling program which returned values of Little Long Lac Gold up to 3.14 g/t Au. Fumerton and Houle (1993) indicate that the mineralization occurs in a banded altered zone with an Mines Limited (21) axial quartz vein in schistose mafic volcanic rocks cut by lamprophyre and granitic dikes. The zone strikes west- The mineralization at this location in northern Keno- northwest and is exposed for a length of 50 m. The banding gaming Township was explored by Little Long Lac Gold occurs on a millimetre to centimetre scale and consists of Mines Limited in 1946, by mapping and 6 diamond-drill iron carbonate-, tourmaline-, sericite- and chlorite-rich holes. The area is underlain by the Nat River iron forma- bands over a width of 1 to 2 m. The axial vein has a highly tion, intermediate to felsic volcanic rocks of the HNA and irregular shape, is discontinuous and varies between 10 cumulate ultramafic to mafic complexes. Lenses of mas- and 20 cm thick. The vein is composed of quartz, albite sive pyrite and pyrrhotite occur up to 1.4 m wide along the and tourmaline, pyrite and arsenopyrite. iron formation contacts. The sulphides and small quartz veins carry low gold values of up to 0.04 ounce Au per ton. Unigold Resources Limited (33) Mining Corp (23) In 1986 and 1987, Unigold Resources Limited explored Stripping, trenching and diamond drilling by Noranda the southeastern part of Muskego Township. Work con- Exploration Company Limited and Storimin Exploration sisted of ground magnetometer, IP and geological surveys, Limited have outlined significant gold mineralization at stripping, trenching and 9 diamond-drill holes. One of the Mining Corp deposit in southeastern Sewell Township. these holes (DDH # UM-2), located about 1 km east of At least 2 mineralized quartz veins have been identified in Highway 101, encountered a 24 m long auriferous inter- diorite on the western margin of the Kenogamissi section with assay values ranging from 0.01 to 0.1 ounce batholith, in Sewell Township. The main vein is exposed Au per ton. The intersection is contained within a unit of at the surface for a length of 120 m and is from 0.3 to 2 m quartz-feldspar porphyry with zones of sericitic alteration thick. The vein occurs in an east-northeast-trending defor- and 1 to 10% pyrite and arsenopyrite. The highest assay mation zone consisting of highly schistose and carbona- results of up to 0.1 ounce Au per ton over 1.8 m are cor- tized diorite up to about 10 m wide. The deformation zone related with the higher sulphide content.

49 OGS REPORT 297

COPPER AND ZINC In addition, an extensive zone of volcanogenic silicification in northeastern Foleyet Township bears resem- The MuskegoÐReeves assemblage (MRA) is considered to blance to similar alteration associated with a number of have the greatest potential for economic concentrations of Archean VMS deposits, including the silicification under- copper and zinc sulphides in the map area. Two distinct lying the Mine Series deposits at Noranda, Quebec types are observed, both of which are considered to be (Gibson et al. 1983). related to exhalative synvolcanic processes: 1) iron formation type and 2) volcanogenic massive sulphide (VMS) type. Dome Exploration (9) The iron formation type of deposits, hosting zinc mineralization with or without copper, are found scattered From 1972 to 1983, Dome Exploration (Canada) Limited throughout the map area. These occurrences appear to be conducted a number of exploration programs in Keith similar to the Shunsby zinc deposit in the southern part of Township. The work included an airborne geophysical the Swayze greenstone belt. The most significant assay survey with detailed follow-up work in the northeastern results are from diamond drilling of banded chert-sulphide- part of the township. It also including ground magnetic facies iron formation and graphitic mudstones, some of and EM surveys and diamond drilling. Anomalous base which contain highly anomalous base metal values. For metal values were detected in a number of diamond-drill example, the sulphide iron formation west of the holes, with the most significant results from a hole about Groundhog River in Keith Township was diamond drilled 1 km south of Slate Rock Lake. This hole intersected a unit by Dome Exploration (Canada) Limited. Over a strike of sulphide iron formation within mafic to intermediate length of about 800 m, 3 diamond-drill holes intersected fragmental rocks. The iron formation consists of black chert and graphitic argillite with sulphide-rich sections graphitic argillite with alternating bands and disseminations containing up to 0.74% Zn and 0.03% Cu over 21 m of pyrite, pyrrhotite, minor sphalerite and chalcopyrite. (described in more detail below). Reported assay values averaged about 0.6% Zn and 0.05% Cu over 22 m. The potential for VMS type deposits appears to be greatest in the northwestern part of the MRA. In this Sulphide iron formations were also explored in the region, diamond drilling has indicated the presence of northeastern part of Keith Township. From 1972 to 1973, stratabound massive to disseminated sulphides with minor Dome Exploration (Canada) Limited conducted ground amounts of sphalerite and chalcopyrite, and associated magnetometer and EM surveys and completed 6 diamond- zones of volcanogenic hydrothermal alteration including drill holes. The highest grade of mineralization was silicification and chloritoid-bearing volcanic rocks. encountered within a base metal-enriched sulphide iron Massive sulphides were also observed as clasts in a con- formation striking east-northeast, west of the Groundhog glomerate in Foleyet Township and as inclusions in the River. It was intersected by 3 holes over a strike length of Ivanhoe Lake pluton, in Ivanhoe Township (Ayer 1993). about 800 m. The iron formation is intercalated with mafic The sulphides are closely associated with felsic, mafic and and ultramafic volcanic rocks and consists of banded ultramafic volcanic rocks (Ayer 1993). In the Abitibi recrystallized chert and graphitic argillite with sulphide- Subprovince, VMS deposits are commonly associated rich sections containing layers of massive to disseminated with this type of compositional diversity (Jackson and sulphides. The sulphides consist mainly of pyrite with Fyon 1991). minor sphalerite and chalcopyrite. The sulphide iron formation in the easternmost hole is relatively zinc-rich, Hydrothermal alteration is evident in Foleyet with an intersection assaying 0.74% Zn and 0.03% Cu Township by the presence of chloritoid porphyroblasts in over 21 m (including assay values of up to 1.4% Zn over carbonatized mafic volcanic rocks that underlie a subeco- 5 m), while the westernmost hole is relatively copper-rich, nomic, strata-bound massive-sulphide horizon located by with assay values of up to 0.3% Cu and 0.25% Zn over 8 m. a diamond-drill hole in southeastern Foleyet Township. Chloritoid porphyroblasts were also observed in outcrops From 1972 to 1977, Dome Exploration (Canada) of carbonatized felsic volcanic rocks along the Ivanhoe Limited conducted an airborne magnetometer survey with River, about 1.5 km east of the above-mentioned drill hole. follow-up ground magnetometer and EM surveys and It is worthy of note that chloritoid-bearing altered volcanic completed 9 diamond-drill holes north of Hoodoo Lake. rocks are associated with a number of Archean vol- Two of the holes intersected sulphide-bearing iron forma- canogenic massive-sulphide deposits (Franklin et al. 1975). tion intercalated with mafic, felsic and ultramafic volcanic Another extensive zone of chloritoid alteration occurs in rocks. The iron formation reportedly consists of a fine- mafic and felsic volcanic rocks within the Slate Rock grained, grey siliceous rock with layers of up to 20% deformation zone in south-central Muskego Township. As pyrrhotite, minor chalcopyrite and sphalerite. Assay chloritoid in greenschist-facies metavolcanic rocks has results from this rock returned values of up to 0.35% Zn been documented to be the result of hydrothermal alter- over 3 m. ation (Lockwood 1986) it is assumed that this zone represents conformable hydrothermal alteration, which could From 1972 to 1973, Dome Exploration (Canada) be associated with sulphide mineralization. Limited conducted ground magnetometer and EM surveys

50 NORTHERN SWAYZE GREENSTONE BELT and diamond-drilled 9 holes on a claim group northwest of 10% Zn and may average about 4% Zn over the width of Groundhog Lake. The drilling indicated a wide variety of the mineralized zone (Fumerton and Houle 1993). volcanic rocks including ultramafic, mafic, intermediate and felsic volcanic rocks with intercalated iron formation. The iron formation consists of a very fine-grained cherty Keevil Mining Group Limited (20) rock with variable amounts of chlorite-, graphite- and sulphide-rich layers. Sulphides included pyrrhotite, pyrite, In 1964 and 1965, Keevil Mining Group Limited conducted chalcopyrite and sphalerite with assay values of up to ground EM and magnetic surveys, geological mapping 0.37% Cu over 2 m and 0.25% Zn over 5 m. and diamond drilling in southeastern Foleyet Township and northeastern Ivanhoe Township.

Hudbay Mining Limited (12) A bore hole was drilled west of Highway 101, on the east side of the old channel of the Ivanhoe River. The hole From 1980 to 1982, Hudbay Mining Limited conducted an intersected mainly mafic volcanic rocks with an interbedded airborne geophysical survey and diamond-drilled 8 holes unit of graphitic mudstone with disseminated pyrrhotite, to follow up on geophysical anomalies in southeastern pyrite, sphalerite and chalcopyrite. Assays from this zone Foleyet and northeastern Ivanhoe townships. One of the returned values of up to 0.35% Zn and 0.07% Cu over 3.5 m. holes in southeastern Foleyet Township intersected a zone of subeconomic stratabound sulphides. Talc-chlorite Three diamond-drill holes (65-18, 65-19, 65-20) were schists, assumed to represent deformed ultramafic flows, also drilled in northeastern Foleyet Township, about 700 are found in the uppermost part of the hole. This unit is to 1100 m east of the southeastern margin of the Ivanhoe succeeded by a unit of locally amygdaloidal chlorite-car- Lake pluton. The drill holes intersected mafic flow units bonate schist which represents altered and deformed mafic with interbedded sedimentary units consisting of wacke, flows containing up to 10% fine- to medium-grained, ran- siliceous siltstone and graphitic mudstone. Sulphide min- domly oriented chloritoid porphyroblasts. The schist is eralization has been reported in all 3 holes associated with abruptly overlain by 8 m of disseminated to massive sul- the mudstone units. In 1 hole, disseminated to semi-massive phides including pyrite, sphalerite and chalcopyrite in pyrite and pyrrhotite with minor sphalerite and chalcopy- graphitic felsic pyroclastic rock. The highest reported zinc rite constitute up to 30 to 70% of the rock over short sections. assay value from this section was 0.6% Zn over 0.9 m. Assays from this section returned anomalous values of up This mineralized section grades down the hole into unmin- to a maximum of 0.28% Zn and 0.05% Cu over 3 m. eralized and unaltered felsic pyroclastic rocks that continue to the end of the hole. Noranda Exploration Company Limited (26) Karvinen (19) Noranda conducted an exploration program on a claim From 1982 to 1986, W. Karvinen, Quinterra Resources group in the northwestern part of Keith Township from and Utah Mines explored for base metals and gold in 1970 to 1972. The work consisted of ground magnetometer northeastern Penhorwood Township by magnetic, EM and and EM surveys and 2 diamond-drill holes. A unit of brec- IP surveys, geological mapping, trenching and diamond- ciated intermediate volcanic rocks with thin stringer veins drilling 1 hole. Sphalerite and chalcopyrite mineralization of pyrrhotite, pyrite and minor chalcopyrite and sphalerite are associated with the Nat River iron formation. Values of was intersected in the western hole (DDH K-72-3). up to 0.9% Zn, 0.1% Cu and 11 g/t Ag were reported in Reported assay results range up to 0.12% Zn and 0.02% Cu selected grab samples. There appears to be some degree of over 1.7 m. structural control to the mineralization, as the iron formation is isoclinally folded and locally brecciated. Highly schistose and carbonatized mafic and ultramafic volcanic United MacFie Mines Limited (34) rocks within the Deerfoot deformation zone lie immediately to the north of the iron formation. Exploration at this occurrence has been concentrated on a copper showing in an enclave of sulphide iron formation In 1986, zinc mineralization was identified by stripping within the Nat River granitic complex, in Muskego and trenching in another showing about 500 m to the Township. From 1970 to 1972, United MacFie Mines northeast (also known as the Nat River zinc showing). Limited conducted ground magnetometer and EM sur- Here, the sulphide mineralization occurs in pillowed to veys, and diamond-drilled 3 holes. Sampling of trenches massive intermediate volcanic rocks of the HNA that on the mineralized zone returned a weighted average of immediately underlie the Nat River iron formation. 0.30% Cu over a width of 8.2 m. The diamond-drill holes Sphalerite mineralization occurs with quartz veins and encountered disseminated sulphides and stringers over minor chalcopyrite and pyrite in a narrow (100 cm) anas- varying widths, consisting of pyrite, pyrrhotite and minor tomosing zone with an exposed strike length of about 100 m. chalcopyrite and sphalerite. Assay results reported in the Results from grab sampling along the zone indicate up to drill logs indicate trace amounts of gold and silver, but

51 OGS REPORT 297 copper and zinc were not reported. Detailed surface exam- Another hole, located further to the north, intersected an ination of the occurrence reported in Thurston et al. (1977) 18 m zone with copper mineralization in a unit identified indicates that the iron formation consists of alternating as a grey banded tuff. The mineralization consists of chal- layers of quartz, sulphides, magnetite and amphibole. copyrite stringers which returned anomalous values of up Locally they contain minor intercalations of what may be to 0.32% Cu. fine-grained, metamorphosed lithic sandstone. The unit has been intruded by pink, medium-grained porphyritic granite and blue-grey quartz diorite. Ireland (14)

NICKEL AND PLATINUM The Ireland occurrence is located in northern Kenogaming Township. It was discovered by Timmins Nickel GROUP ELEMENTS Incorporated in 1989 and explored in 1990 by stripping, trenching and diamond drilling. The showing consists of Nickel occurrences are closely associated with the cumulate- cumulate-textured dunites differentiating into melagabbro, textured ultramafic rocks, mostly within the Hanrahan isoclinally interfolded with magnetite-chert iron formation assemblage (HNA). The presence of large ultramafic bodies, and felsic tuffs of the underlying HNA. Mineralization some of which have documented nickel mineralization, is consists of 1 to 2% disseminated sulphides which locally an indication that there may be good potential for komatiite- form a poorly developed net texture containing up to 10% hosted nickel deposits similar to those found in the sulphides. The sulphides consist of pyrrhotite and minor Timmins area and the Kambalda area of Australia (Lesher amounts of pentlandite. Late fractures are also mineralized 1989). In addition, locally elevated platinum group ele- with pentlandite. Grab samples returned assay values of up ment levels in assay results are also of exploration interest. to 0.94% Ni, 0.10% Cu, 0.27 g/t Pt and 0.2 g/t Pd. Geochemical analyses of the ultramafic rocks in the vicinity of the mineralization show REE patterns that are dis- Akweskwa Lake (1) tinctively different than those of similar, but unmineral- ized, ultramafic rocks in the same unit to the northeast. There may be some confusion about the location of this The slightly elevated LREE patterns in the rock hosting showing in Kenogaming Township, as the area is under- the mineralization suggest that contamination of the ultra- lain by numerous ultramafic bodies, a number of which mafic magmas may be the mechanism responsible for have associated nickel mineralization. A grab sample taken localizing the sulphides and platinum group element min- at this location is reported to have assay values of 1% Cu eralization (see “Geochemistry”). and 0.9% Ni (Milne 1972). In 1973, Hanna Mining conducted a regional survey and sampled ultramafic rocks over much of Kenogaming Township. The highest returned McIntyre Johnson (22) assay value in this immediate area was only 0.30% Ni. Fumerton and Houle (1993) report a massive, fine- to medium-grained, highly serpentinized peridotite with The McIntyre Johnson occurrence lies in poorly exposed, about 2% disseminated sulphides at the indicated area of amphibolite-facies mafic metavolcanic rocks in the east- mineralization, but could not find any evidence of channel central part of Sewell Township. McIntyre Porcupine sampling. Grab samples collected by Fumerton and Houle Mines Limited carried out geophysical surveys followed (1993) returned values of up to 0.28% Ni and 0.13% Cu. by diamond drilling in 1971. The mineralization is reported as millerite which occurs in aggregates and along joint surfaces within a differentiated mafic intrusion. Reported Amax Minerals Limited (2) assay values are up to 0.2% Ni over 2.3 m within peridotite.

Amax minerals conducted a magnetic and EM survey in 1978 that was followed up by a diamond-drill hole in Norduna (27) 1979, in northeastern Kenogaming Township. Drill logs report assay values of up to 0.25% Ni over 3 m within a The Norduna occurrence is located within a cumulate- carbonatized and serpentinized ultramafic unit containing textured ultramafic body within the HNA, in central talc and chlorite bands. Kenogaming Township. There has been considerable exploration work on this occurrence since its discovery in 1947. This work has included geophysical surveys, strip- International Norvalie (13) ping, trenching and diamond drilling, with the most recent work by Falconbridge Limited. The mineralization con- In 1971, Norvalie Mines Limited optioned the Jonsmith sists of up to 5% disseminated sulphides in serpentinized property in east-central Kenogaming Township and dia- ultramafic rocks that are in close proximity to the sheared mond drilled a number of holes in this area, east of the contact with intermediate fragmental rocks to the south. occurrence. One of the holes returned a value of 0.26% Ni The best reported intersection was 0.88% Ni and 0.156% over 3 m of serpentinized ultramafic rock containing 1 to 2% Cu over 7.6 m, including a 1.5 m section with 1.25% Ni disseminated and fracture-filled pyrrhotite and pyrite. and 0.24% Cu.

52 NORTHERN SWAYZE GREENSTONE BELT

IRON carbonate facies (0 to 50 m in thickness); 2) oxide facies with minor carbonate and silicate facies (30 to 100 m in There are 2 economically important iron formations in the thickness); 3) carbonate and silicate facies (10 to 80 m in map area: 1) the Radio Hill iron formation and 2) the Nat thickness); and 4) sulphide facies (0 to 25 m in thickness). River iron formation. The iron deposits in both of these iron formations occur where the iron formation appears to thicken by folding and/or faulting. ASBESTOS There are numerous asbestos occurrences within the ultra- Nat River (24) mafic rocks scattered throughout the map area. However, the only economically significant deposit is that of the Geophysical surveys and 14 diamond-drill holes by Reeves Mine, which produced about 146 000 tons of Kukatush Mining Corporation Limited, from 1959 to asbestos. Milne (1972) concluded 1) asbestos mineraliza- 1965, outlined a potential iron deposit containing an esti- tion is always associated with faulting and ductile deforma- mated 27 million tons of 29% total iron in northeastern tion; 2) the formation of the asbestos veins was a separate Penhorwood Township. The deposit occurs within the Nat event from the general serpentinization of the ultramafic River iron formation on the northern limb of the Hanrahan rocks; and 3) the asbestos veins are later than the main Lake anticline. The continuity of the Nat River iron for- metamorphic events affecting the ultramafic rocks. mation has been largely inferred from magnetic surveys and details have not been established. The diamond drilling clearly indicates the deposit area is underlain by a Reeves Mine (30) number of iron formation intersections (Milne 1972). A The Reeves asbestos mine is located in southeastern possible interpretation shown on Map 2627 (back pocket) Reeves Township. Exploration continued over a period is that of a Z-shaped, isoclinal drag fold on the north limb of about 20 years and production was started in 1968 of an F1 anticline. Alternative interpretations are repetition by Johns Manville Limited. It produced a total of about by faulting or a number of separate iron formation horizons. 146 000 tonnes of asbestos from about 6 million tons of ore. Production was divided between a large western pit The iron formation consists predominantly of lean, and a smaller eastern pit by a north-trending diabase dike. finely banded magnetite- and chert-facies iron formation. In addition, sulphide-, silicate-, carbonate-, and graphite- The ore body is situated within the northern part of a facies portions are locally present in lesser amounts. The differentiated ultramafic to gabbroic body 120 to 300 m oxide-facies portions typically consist of thin, lean beds of thick, which also hosts the Penhorwood talc mine to the south. black chert containing magnetite interbedded with white The ore zones occur in serpentinized dunite in the northern nonmagnetic chert on a centimetre scale. The sulphide- closure of an antiformal structure which plunges about 50¡ facies portions occur as beds of disseminated to massive to the northeast. An easterly facing direction, based on the pyrite and minor pyrrhotite up to 20 cm thick interbedded differentiation from dunite to gabbro (see “Geochemistry”), with chert and/or graphitic argillite. and an S1 fabric which wraps around the nose of the fold, indicates that the fold is an F2 antiformal syncline. This Radio Hill (29) north-trending fold has been cut by northeast-trending shears. A major northeast-trending shear crosses the north- Exploration work by Kukatush Mining Corporation ern apex of the antiformal syncline. The dip of this fault is Limited from 1958 to 1965, including geophysical sur- approximately 55¡ to the northwest at the surface but flattens veys, mapping, trenching and diamond drilling, has indi- with depth. Drag folding suggests that it is a reverse fault cated an iron deposit with approximately 158 million tons in which the north side has moved upwards (Milne 1972). of magnetic iron ore grading 27.8% acid-soluble iron. The The orebody is enclosed to the west, north and east by deposit occurs near the eastern end of the Radio Hill iron about 30 m of barren serpentinite in contact with mafic formation in northwestern Penhorwood Township. The volcanic rocks. Thus, the ore zone appears to conform iron deposit has a strike length of 5000 m and a thickness with the general trend of the antiform and has 3 dominant of up to 500 m. This abnormal thickness is probably the structural controls: 1) the apex of a tight fold; 2) drag folds result of structural modification by at least 2 episodes of caused by a steep reverse fault; and 3) major asbestos fibre folding. It is overlain by komatiite flows to the north and development is confined to the serpentinized dunitic part underlain to the south by thickly bedded wacke. The iron of a differentiated ultramafic to gabbroic body (Milne 1972). formation is folded into an isoclinal S-shape fold (F2 folding) plunging north-northwest at about 50¡ (Milne 1972). The The asbestos in the ore zone occurs in a complex net- unit consists of magnetite, siderite, sulphide, silicate work of veins of various ages. The average grade of the (minnesotaite), hematite (jasper) and graphite iron formation ore ranges from 2.5 to 4%, with fibres ranging in length typically interbedded with chert. from less than 5 mm up to 15 mm. Many of the asbestos fibres are composite in nature, with magnetite occurring Milne (1972) has characterized 4 major vertical facies either as a sandwich between 2 parallel veins of asbestos transitions in the Radio Hill area. They are, from south to or as a selvage on one wall of the asbestos vein. Ribbon north (hanging wall to footwall) 1) sulphide, silicate and veins, consisting of a central magnetite-asbestos vein bor-

53 OGS REPORT 297 dered on both sides by several parallel asbestos veins, also were produced from small operations prior to 1940. Reserve occur. Where the diabase dike cuts the orebody, the calculations indicate a probable reserve of 90 000 tonnes asbestos fibres have been recrystallized and destroyed for grading 95% barite. Milne (1972) indicated that the up to 3 m on either side of the dike (Milne 1972). deposit occurs along the southeastern margin of the Kukatush pluton. However, this investigation and high- resolution aeromagnetic patterns suggest the deposit TALC occurs near the southern margin of an elongate body of foliated granodiorite and granite intruded between the A number of talc occurrences are associated with the Kukatush pluton and Kenogamissi batholith. Intense duc- ultramafic rocks of the area. The Penhorwood Mine is the tile deformation associated with the Hardiman deformation only currently producing deposit in the map area. It is sit- zone is focussed along the southeastern margin of this uated near the sheared western margin of a large differen- intrusion and it is in this setting that the Cryderman, tiated ultramafic to gabbroic body which also hosts the Horwood (11) and Roseval (31) veins are situated. Reeves asbestos mine. The talc mineralization appears to be associated with early ductile deformation overprinted by localized fracturing and pervasive talc-carbonate alteration. The barite occurs in a northeast-trending vein structure which has been traced over a strike length of 500 m. Individual veins pinch and swell, from stringers to up to 5 m Penhorwood Mine (28) thick, and have been traced for 30 m. The veins are typically zoned from quartz and fluorite at the wall rock contact to The Penhorwood Mine is currently operated by Luzenac laminated barite and calcite in the walls and massive barite Incorporated, with a milling rate of 450 tons to produce in the centre. 170 to 200 tons of concentrate per day. There is very little data available on the reserves or dimensions of the deposit. The open pit deposit is located near the western margin of SILICA an extensive north-trending, cumulate-textured serpentinite body cut by east-trending deformation zones, in north- Silica, used for decorative stone and smelter flux, has been eastern Penhorwood Township. The ultramafic unit also sporadically produced from a number of open pits on large hosts the Reeves asbestos mine further to the north. The quartz veins, in the southwestern part of Penhorwood western margin of the ultramafic unit is highly deformed Township. and may be the locus of a sheared contact with a unit of clastic sedimentary rocks to the west. Horwood Mine (11) Fumerton and Houle (1993) indicate that a number of In 1964, Horwood Mines Limited produced a total of intense zones of talc-carbonate alteration occur along a 800 tonnes of silica from a quartz vein in southwestern northeast line just east of a parallel shear inferred from Penhorwood Township. The quartz veins occur along the geophysical data. There are several generations of frac- southeastern margins of elongate, foliated granodiorite tures that cut the deposit, all of which have varying and granite bodies intruded between the Kukatush pluton amounts of recrystallized magnesite and talc along the and Kenogamissi batholith. The veins occur in highly fracture plane. The ore consists of about 50% talc. It is a strained wall rock within the Hardiman deformation zone. massive, medium-grained, light grey rock consisting of The Horwood deposit is located in the southwestern part vitreous talc and translucent carbonate grains together of a quartz vein which has been traced for a length of with disseminated grains of ilmenite and/or magnetite. about 550 m and is up to 20 m thick. One of the Roseval Based on chemical analyses, the CaO content varies quartz deposits is situated on the northeastern part of the between 0.3% and 4.5% and FeO varies between 5% and same vein system. 8.5%. The massive rock is cut by a number of recrystallized talc and magnesite veins in a number of different fracture orientations. Roseval Mine (31) In 1987 and 1988, Roseval Silica Incorporated produced BARITE about 110 000 tonnes of silica from their number 2 and 3 zones. The veins making up these zones occur within paral- The Cryderman Mine is the only recorded barite occur- lel shears of the Hardiman deformation zone, situated at the rence in the map area. highly deformed southeast margins of elongate foliated granodiorite to granite bodies that have intruded between the Cryderman Mine (8) Kukatush pluton and the Kenogamissi batholith. The number 2 zone is at the north end of the vein system which hosts The Cryderman barite deposit is located in southwestern the Horwood Mine. The number 3 zone, which occurs on a Penhorwood Township. It was discovered in 1917 and since different quartz vein several hundred metres to the north, is that time has been the focus of a considerable amount of located at the highly strained contact of a granite intrusion exploration, including a 450 m decline in 1984 by with ultramafic talc-chlorite schists. This vein has been Extender Minerals Limited. A total of 673 tonnes of barite traced along strike for about 200 m and is up to 50 m thick.

54 NORTHERN SWAYZE GREENSTONE BELT References

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Ontario Geological Survey 1990. Airborne electromagnetic and total Stone, W.E., Jensen, L.S. and Church, W.R. 1987. Petrography and geo- intensity magnetic survey, north SwayzeÐMontcalm area; Ontario chemistry of an unusual Fe-rich basaltic komatiite from Boston Geological Survey; Maps 81367 to 81372, 81374 to 81379, scale Township, northeastern Ontario; Canadian Journal of Earth 1:20 000. Science, v.24, p.2537-2550.

Osmani, I.A. 1991. Proterozoic mafic dike swarms in the Superior Tanton, T.L. 1917. Reconnaissance along the Canadian Northern Railway Province of Ontario; in Geology of Ontario, Ontario Geological between Gogama and Oba, Sudbury and Algoma districts; in Survey, Special Volume 4, Part 1, p.661-681. Geological Survey of Canada, Summary Report for 1916, p.179-182.

Parks, W.A. 1900. Niven’s Base Line, 1899; in Ontario Bureau of Mines, Thurston, P.C., Siragusa, G.M. and Sage, R.P. 1977. Geology of the Annual Report, v.9, p.125-142. Chapleau area, districts of Algoma, Sudbury and Cochrane; Ontario Division of Mines, Geological Report 157, 293p. Pearce, J.A. and Cann, J.R. 1973. Tectonic setting of basic volcanic rocks determined using trace element analyses; Earth and Planetary Watson, K.D., Bruce, G.S.W. and Halladay, L.B. 1978. Kimberlitic dyke Science Letters, v.19, p.290-300. in Keith Township; Canadian Mineralogist, v.16, p.97-102.

56 NORTHERN SWAYZE GREENSTONE BELT Metric Conversion Table

CONVERSION FACTORS FOR MEASUREMENTS IN ONTARIO GEOLOGICAL SURVEY PUBLICATIONS

Conversion from SI to Imperial Conversion from Imperial to SI

SI Unit Multiplied by Gives Imperial Unit Multiplied by Gives

LENGTH 1 mm 0.039 37 inches 1 inch 25.4 mm 1 cm 0.393 70 inches 1 inch 2.54 cm 1 m 3.280 84 feet 1 foot 0.304 8 m 1 m 0.049 709 7 chains 1 chain 20.116 8 m 1 km 0.621 371 miles (statute) 1 mile (statute) 1.609 344 km

AREA 1 cm2 0.155 square inches 1 square inch 6.451 6 cm2 1 m2 10.763 9 square feet 1 square foot 0.092 903 04 m2 1 km2 0.386 10 square miles 1 square mile 2.589 988 km2 1 ha 2.471 054 acres 1 acre 0.404 658 6 ha

VOLUME 1 cm3 0.061 02 cubic inches 1 cubic inch 16.387 064 cm3 1 m3 35.134 7 cubic feet 1 cubic foot 0.028 316 85 m3 1 m3 1.308 0 cubic yards 1 cubic yard 0.764 555 m3

CAPACITY 1 L 1.759 755 pints 1 pint 0.568 261 L 1 L 0.879 877 quarts 1 quart 1.136 552 L 1 L 0.219 969 gallons 1 gallon 4.546 090 L

MASS 1 g 0.035 273 96 ounces (avdp) 1 ounce (advp) 28.349 523 g 1 g 0.032 150 75 ounces (troy) 1 ounce (troy) 31.103 476 8 g 1 kg 2.204 62 pounds (avdp) 1 pound (avdp) 0.453 592 37 kg 1 kg 0.001 102 3 tons (short) 1 ton (short) 907.184 74 kg 1 t 1.102 311 tons (short) 1 ton (short) 0.907 184 74 t 1 kg 0.000 984 21 tons (long) 1 ton (long) 1016.046 908 8 kg 1 t 0.984 206 5 tons (long) 1 ton (long) 1.016 046 908 8 t

CONCENTRATION 1 g/t 0.029 166 6 ounce(troy)/ 1 ounce(troy)/ 34.285 714 2 g/t ton(short) ton(short) 1 g/t 0.583 333 33 pennyweights/ 1 pennyweight/ 1.714 285 7 g/t ton(short) ton(short)

OTHER USEFUL CONVERSION FACTORS

Multiplied by 1 ounce(troy) per ton (short) 20.0 pennyweights per ton (short) 1 pennyweight per ton (short) 0.05 ounces (troy) per ton (short)

Note: Conversion factors which are in bold type are exact. The converion factors have been taken from or have been derived from factors given in the Metric Practice Guide for the Canadian Mining and Metallurgical Industries, published by the Mining Association of Canada in co-operation with the Coal Association of Canada.

57 OGS Report 300

2 OGS REPORT 297

58 NORTHERN SWAYZE GREENSTONE BELT

ISSN 0704-2582 ISBN 0-7778-3813-3