THESE TERMS GOVERN YOUR USE OF THIS DOCUMENT

Your use of this Ontario Geological Survey document (the “Content”) is governed by the terms set out on this page (“Terms of Use”). By downloading this Content, you (the “User”) have accepted, and have agreed to be bound by, the Terms of Use.

Content: This Content is offered by the Province of Ontario’s Ministry of Northern Development and Mines (MNDM) as a public service, on an “as-is” basis. Recommendations and statements of opinion expressed in the Content are those of the author or authors and are not to be construed as statement of government policy. You are solely responsible for your use of the Content. You should not rely on the Content for legal advice nor as authoritative in your particular circumstances. Users should verify the accuracy and applicability of any Content before acting on it. MNDM does not guarantee, or make any warranty express or implied, that the Content is current, accurate, complete or reliable. MNDM is not responsible for any damage however caused, which results, directly or indirectly, from your use of the Content. MNDM assumes no legal liability or responsibility for the Content whatsoever.

Links to Other Web Sites: This Content may contain links, to Web sites that are not operated by MNDM. Linked Web sites may not be available in French. MNDM neither endorses nor assumes any responsibility for the safety, accuracy or availability of linked Web sites or the information contained on them. The linked Web sites, their operation and content are the responsibility of the person or entity for which they were created or maintained (the “Owner”). Both your use of a linked Web site, and your right to use or reproduce information or materials from a linked Web site, are subject to the terms of use governing that particular Web site. Any comments or inquiries regarding a linked Web site must be directed to its Owner.

Copyright: Canadian and international intellectual property laws protect the Content. Unless otherwise indicated, copyright is held by the Queen’s Printer for Ontario.

It is recommended that reference to the Content be made in the following form: , . ; Ontario Geological Survey, , p.

Use and Reproduction of Content: The Content may be used and reproduced only in accordance with applicable intellectual property laws. Non-commercial use of unsubstantial excerpts of the Content is permitted provided that appropriate credit is given and Crown copyright is acknowledged. Any substantial reproduction of the Content or any commercial use of all or part of the Content is prohibited without the prior written permission of MNDM. Substantial reproduction includes the reproduction of any illustration or figure, such as, but not limited to graphs, charts and maps. Commercial use includes commercial distribution of the Content, the reproduction of multiple copies of the Content for any purpose whether or not commercial, use of the Content in commercial publications, and the creation of value-added products using the Content.

Contact:

FOR FURTHER PLEASE CONTACT: BY TELEPHONE: BY E-MAIL: INFORMATION ON The Reproduction of MNDM Publication Local: (705) 670-5691 Content Services Toll Free: 1-888-415-9845, ext. [email protected] 5691 (inside Canada, United States) The Purchase of MNDM Publication Local: (705) 670-5691 MNDM Publications Sales Toll Free: 1-888-415-9845, ext. [email protected] 5691 (inside Canada, United States) Crown Copyright Queen’s Printer Local: (416) 326-2678 [email protected] Toll Free: 1-800-668-9938 (inside Canada, United States)

LES CONDITIONS CI-DESSOUS RÉGISSENT L'UTILISATION DU PRÉSENT DOCUMENT.

Votre utilisation de ce document de la Commission géologique de l'Ontario (le « contenu ») est régie par les conditions décrites sur cette page (« conditions d'utilisation »). En téléchargeant ce contenu, vous (l'« utilisateur ») signifiez que vous avez accepté d'être lié par les présentes conditions d'utilisation.

Contenu : Ce contenu est offert en l'état comme service public par le ministère du Développement du Nord et des Mines (MDNM) de la province de l'Ontario. Les recommandations et les opinions exprimées dans le contenu sont celles de l'auteur ou des auteurs et ne doivent pas être interprétées comme des énoncés officiels de politique gouvernementale. Vous êtes entièrement responsable de l'utilisation que vous en faites. Le contenu ne constitue pas une source fiable de conseils juridiques et ne peut en aucun cas faire autorité dans votre situation particulière. Les utilisateurs sont tenus de vérifier l'exactitude et l'applicabilité de tout contenu avant de l'utiliser. Le MDNM n'offre aucune garantie expresse ou implicite relativement à la mise à jour, à l'exactitude, à l'intégralité ou à la fiabilité du contenu. Le MDNM ne peut être tenu responsable de tout dommage, quelle qu'en soit la cause, résultant directement ou indirectement de l'utilisation du contenu. Le MDNM n'assume aucune responsabilité légale de quelque nature que ce soit en ce qui a trait au contenu.

Liens vers d'autres sites Web : Ce contenu peut comporter des liens vers des sites Web qui ne sont pas exploités par le MDNM. Certains de ces sites pourraient ne pas être offerts en français. Le MDNM se dégage de toute responsabilité quant à la sûreté, à l'exactitude ou à la disponibilité des sites Web ainsi reliés ou à l'information qu'ils contiennent. La responsabilité des sites Web ainsi reliés, de leur exploitation et de leur contenu incombe à la personne ou à l'entité pour lesquelles ils ont été créés ou sont entretenus (le « propriétaire »). Votre utilisation de ces sites Web ainsi que votre droit d'utiliser ou de reproduire leur contenu sont assujettis aux conditions d'utilisation propres à chacun de ces sites. Tout commentaire ou toute question concernant l'un de ces sites doivent être adressés au propriétaire du site.

Droits d'auteur : Le contenu est protégé par les lois canadiennes et internationales sur la propriété intellectuelle. Sauf indication contraire, les droits d'auteurs appartiennent à l'Imprimeur de la Reine pour l'Ontario. Nous recommandons de faire paraître ainsi toute référence au contenu : nom de famille de l'auteur, initiales, année de publication, titre du document, Commission géologique de l'Ontario, série et numéro de publication, nombre de pages.

Utilisation et reproduction du contenu : Le contenu ne peut être utilisé et reproduit qu'en conformité avec les lois sur la propriété intellectuelle applicables. L'utilisation de courts extraits du contenu à des fins non commerciales est autorisé, à condition de faire une mention de source appropriée reconnaissant les droits d'auteurs de la Couronne. Toute reproduction importante du contenu ou toute utilisation, en tout ou en partie, du contenu à des fins commerciales est interdite sans l'autorisation écrite préalable du MDNM. Une reproduction jugée importante comprend la reproduction de toute illustration ou figure comme les graphiques, les diagrammes, les cartes, etc. L'utilisation commerciale comprend la distribution du contenu à des fins commerciales, la reproduction de copies multiples du contenu à des fins commerciales ou non, l'utilisation du contenu dans des publications commerciales et la création de produits à valeur ajoutée à l'aide du contenu.

Renseignements :

POUR PLUS DE VEUILLEZ VOUS PAR TÉLÉPHONE : PAR COURRIEL : RENSEIGNEMENTS SUR ADRESSER À : la reproduction du Services de Local : (705) 670-5691 contenu publication du MDNM Numéro sans frais : 1 888 415-9845, [email protected] poste 5691 (au Canada et aux États-Unis) l'achat des Vente de publications Local : (705) 670-5691 publications du MDNM du MDNM Numéro sans frais : 1 888 415-9845, [email protected] poste 5691 (au Canada et aux États-Unis) les droits d'auteurs de Imprimeur de la Local : 416 326-2678 [email protected] la Couronne Reine Numéro sans frais : 1 800 668-9938 (au Canada et aux États-Unis)

Ontario Division of Mines

HONOURABLE LEO BERNIER, Minister of Natural Resources DR. J. K. REYNOLDS, Deputy Minister of Natural Resources G. A. Jewett, Executive Director, Division of Mines E. Q. Pye, Director, Geological Branch

Heavy Mineral Indicators in Alluvial and Esker Gravels of the Moose River Basin, James Bay Lowlands

District of Cochrane

By W. J. Wolfe, H. A. Lee, and W. D. Hicks

Geoscience Report 126

TORONTO 1975 ODM 1974

Publications of the Ontario Division of Mines and price list are obtainable through the Mines Publications Office, Ontario Ministry of Natural Resources Parliament Buildings, Queen©s Park Toronto, Ontario and The Ontario Government Bookstore 880 Bay Street, Toronto, Ontario. Orders for publications should be accompanied by cheque, or money order, payable to Treasurer of Ontario.

Parts of this publication may be quoted if credit is given to the Ontario Division of Mines. It is recommended that reference to this report be made in the following form:

Wolfe, W. J., Lee, H. A., and Hicks, W. D. 1975: Heavy Mineral Indicators in Alluvial and Esker Gravels of the Moose River Basin, James Bay Lowlands, District of Cochrane. Ontario Div. Mines, GR126, 60p. Accompanied by Map 2334, scale l inch to 4 miles.

1,000 H.R. 75 CONTENTS

PAGE Abstract ...... v Introduction ...... l Location and Access ...... l Acknowledgments ...... 2 Previous Studies ...... 3 Physical Features ...... 4 Regional Geology and Geophysics ...... 6 Post-Middle Devonian Ultramafic Intrusions ...... 9 Kapuskasing Gravity High ...... 12 Quaternary Geology ...... 13 Investigation of Heavy Minerals ...... 18 The Search for Kimberlite Indicators ...... 18 Sampling and Gravity Concentration of Heavy Minerals ...... 18 Laboratory Examination of Mineral Concentrates ...... 22 Mineralogy and Chemistry of the Kimberlite Indicator Minerals ...... 24 Garnet ...... 26 Diopside ...... 29 Ilmenite ...... 30 The Source of Kimberlite Indicator Minerals ...... 30 Distribution of Pyrope Garnets in the James Bay Lowlands ...... 30 Reconstruction of Pyrope Transport History in Quaternary Time ...... 31 Airborne Geophysical Exploration for Kimberlite ...... 32 Geochemistry of Esker Clasts and Heavy Minerals in Drift Covered Terrain ...... 34 Esker A ...... 37 Esker B ...... 40 Esker C ...... 41 Esker D ...... 41 Esker E ...... 41 The Paleozoic-Precambrian Boundary ...... 45 Appendix A ...... 47 Appendix B ...... 53 References ...... 55 Index ...... 59

Tables 1-Table of Lithologic Units ...... 7 2-Chemical analyses of ultramafic dikes ...... 11 3-Quaternary rock-stratigraphic units and inferred events ...... 14 4-Electron microprobe analyses of pyrope garnets ...... 28 5-Partial chemical analyses of chromium-bearing diopside grains ...... 29 6-Chemical analyses of ilmenite grains ...... 30 7-Trace element concentrations of heavy minerals ...... 35 8-Trace element analyses of mineralized esker clasts ...... 36 iii PAGE Figures 1-Key Map showing location of the Moose River Basin Area ...... v 2-Regional Geology of the Kapuskasing-Moose River Area with superimposed gravity contours Chart A, back pocket 3-Regional Aeromagnetic Map of the Kapuskasing-Moose River Area ...... Chart A, back pocket 4-Directions of ice-movement for Adam Till ...... 16 5-Variations in the relative abundances of 8 mm-16 mm sized rock clasts in Esker A ...... 38 6-Variations in the relative abundances of 8 mm-16 mm sized rock clasts in Esker B ...... 39 7-Variations in the relative abundances of 8 mm-16 mm sized rock clasts in Esker C ...... 42 8-Variations in the relative abundances of 8 mm-16 mm sized rock clasts in Esker D ...... 43 9-Variations in the relative abundances of 8 mm-16 mm sized rock clasts in Esker E ...... 44

Photographs 1-The James Bay Lowland, a poorly drained coastal plain ...... 5 2-Thin deposits of (l) stratified clay-silt sediments of the Barlow-Ojibway Formation, (2) Cochrane Till, and (3) post-Cochrane clay; all overlying cobbly esker gravels ...... 17 3-On site screening of alluvial sand and gravel ...... 19 4-Bullseye of heavy minerals ...... 21 5-Mineralogy of heavy mineral fraction* ...... 23 6-Well rounded garnets* ...... 25 7-Angular fragment of pyrope* ...... 25 8-Illustration of size difference between angular and rounded garnets* ...... 27 9-Pyrope garnets* ...... 27 *Original colour photographs of Photos l to 9 are on file at the Mines Library, Onatrio Ministry of Natural Resources, Toronto.

Geological Map (back pocket) Map 2334-Moose River Basin, James Bay Lowlands, District of Cochrane. Scale l inch to 4 miles.

Chart (back pocket) Chart A-Figure 2, Figure 3

IV ABSTRACT

A reconnaissance survey of 5,000 square miles (12,950 km2 ) of the Moose River drainage basin was designed to (1) locate concentrations of kimberlite-associated heavy minerals in glacial tills, alluvial sediments and esker gravels, and (2) assess the metal potential and lithology of pre-Quaternary subcrop in a region of extensive drift cover by geochemical analysis of heavy mineral concentrates and statistical counts of 8-16 mm-sized rock clasts in esker gravel deposits.

a ©~ SS" 83" 81" SMC 13174 Scale, l inch to 200 miles Figure 1-Key map showing location of Moose River Basin Area. Scale of Key map 1:12, 672,000.

The survey area is traversed by the northeast-trending Kapuskasing granulite structural zone. Geological mapping at the reconnaissance level has confirmed close correlations between a regional northeast-trending positive gravity anomaly, a zone of major northeast faulting, and the northeast-trending zone of granulite metamorphic grade; features which support the concept of crustal thinning and uplift along the axis of the gravity high. Twenty grains of pyrope-rich garnet and one grain of magnesian ilmenite were identified in heavy mineral concentrates recovered mainly from samples of alluvial gravel collected from rivers draining the northwest flank of the Kapuskasing granulite zone. For the first time, pyrope garnets have been recognized in esker deposits situated southeast of the Kapuskasing structure. Con centrations of pyrope in samples of alluvium are extremely low; generally not exceeding 2 grains per 4.5 litre sample. The distribution of pyrope garnets along the Little Abitibi and North French Rivers can be adequately explained by alluvial transport of pyrope grains derived from a dispersed secondary source in till sheets deposited by ice advancing from the northeast quadrant. The postulated existence of subsurface kimberlite pipes at the bedrock-overburden interface in interfluve areas situated northeast of the Abitibi and North French drainage systems would be consistent with a concept of two-stage transport of indicator minerals. An ultramafic dike similar to lamprophyre sills and dikes at Coral Rapids and Sextant Rapids, was discovered intruding highly sheared granulite gneisses along the Little Abitibi River in south-central Wacousta Township. In extensive drift-covered regions south of the Precambrian-Paleozoic boundary, it has been possible to infer the existence of several minor, but previously unrecognized belts of Archean- type metavolcanic-metasedimentary rocks on the basis of down-ice increases in the abundances of mafic volcanic, felsic volcanic, chert, argillite and greywacke clasts in esker gravels. A large num ber of mineralized pebbles collected from a south-trending esker located north of Kapuskasing, were identified as quartz-feldspar-mica (sericite-chlorite) rocks containing disseminated pyrite, pyrrhotite and minor chalcopyrite and molybdenite. Many of these granitic clasts contain anomal ously high concentrations of copper (104 ppm to 790 ppm) and molybdenum (2 ppm to 4 ppm).

VI Heavy Mineral Indicators in Alluvial and Esker Gravels of the Moose River Basin James Bay Lowlands, District of Cochrane by W. J. Wolfe1, H. A. Lee2, and W. D. Hicks3

INTRODUCTION

During 073, the Geophysics/Geochemistry Section of the Geological Branch supervised th? planning and completion of a regional survey of 5,000 square miles (12,950 km2 ) of the James Bay Lowland with the purpose of outlining the distribu tion of diagnostic heavy minerals associated with the subsurface occurrence of pos sible diamondj-bearing kimberlite pipes and diatremes. The survey was designed to (l) locate concentrations of the minerals pyrope garnet, magnesian ilmenite, chrome diopside and diamond, in river and esker gravels of the Moose River Basin, and (2) examine the metal potential and lithology of pre-Quaternary subcrop in a region of extensive drift cover by geochemical analysis of heavy mineral concentrates and statistical counts of pebble-sized rock clasts in esker gravel deposits. The field sampling, preliminary concentration of heavy minerals in the field, and a study of the Quaternary geology and stratigraphy, were carried out under a contract awarded to Lee Geo-Ibdicators Limited of Stittsville, Ontario. Preparation of final heavy media concentrates, mineralogical studies, and chemical analyses were performed by the Mineral Research Branch of the Ontario Division of Mines.

LOCATION AND ACCESS

Within the general area of investigation outlined in Figure l, sampling of alluvial and esker deposits was mainly concentrated in the region extending from

1Chief, Geophysics/Geochemistry Section, Geological Branch, Ontario Division of Mines, Toronto. 2President, Lee Geo-Indicators Limited, Stittsville, Ontario. Mineralogist, Mineral Research Branch, Ontario Division of Mines, Toronto. Manuscript approved for publication by the Director, Geological Branch, 16 July 1974. 1 Heavy Mineral Indicators of the Moose River Basin

Latitude 49 030© to 51 000©N and bounded to the east by Longitude 80030©W and to the west by the Abitibi River. Additional esker sampling was carried out in an area between the Opasatika and Mattagami Rivers from Latitude 49030© to Latitude 50000©N. Cochrane to the south of the map-area and Moosonee to the north, are connected by the Ontario Northland Railway which bisects the area in a north- south direction and provides twice-daily rail service. A railway spur line operated by the Spruce Falls Pulp and Paper Company connects Smoky Falls in the western part of the project-area with the town of Kapuskasing. Highway 807 links the towns of Smoky Falls and Fraserdale and joins Highway 11 at Smooth Rock Falls. A railway car provided by the Ontario Northland Railway served as a mobile base camp, field laboratory and office and was moved to suitable sidings along the O.N.R. line at Onakawana, Ranoke, and Fraserdale. Aviation gasoline was trans ported by rail from Cochrane and dumped at these sidings. A Hiller 12E helicopter was used to provide transportation between the base camp and the field sampling sites. Additional field base camps were established for short periods at McParlon Lake in the east-central part of the area, and at Remi Lake near the southwestern corner of the project area. H.A. Lee, D.H. Frobel, and D.K. Fraser of Lee Geo-Indicators Limited, were on the field sites from June 25 to August 20, 1973. The project was timed to coincide with the lowest water-levels. Weather conditions during the summer of 1973 were dry and hot and the water-levels in the Moose River Basin were unusually low. Helicopter landings on gravel bars and boulder areas in the middle of the rivers were made with ease and the low water-levels provided maximum exposure of bedrock and near-bedrock alluvium in the river channels.

ACKNOWLEDGMENTS

Because of the special nature of this project, experienced personnel were required to undertake the field sampling program. H.A. Lee was responsible for collection of the samples, correlation of the field data with the overall Quaternary stratigraphy, and setting up flow-sheets and procedures for the laboratory processing and mineralogical examination of the samples. D.H. Frobel assisted in the sampling of field sites, and D.K. Fraser carried out gravitation and panning procedures at the field base camp to obtain preliminary heavy mineral concentrates. W.D. Hicks and S.J. McCance of the Ontario Division of Mines, Mineral Research Branch, did petrographic investigations, examined the heavy mineral concentrates, and identified the kimberlite indicator minerals. Electron microprobe analyses were done by Aykut Tuemer of the Mineral Research Branch using equipment and standards made available by the Department of Geology, University of Toronto, through the courtesy of Professor J.A. Rucklidge. Rock clasts collected at esker sites were systematically classified and counted by S.R. Parmar. The project was supervised and co-ordinated by WJ. Wolfe of the Ontario Division of Mines, Geological Branch. PREVIOUS STUDIES

The Moose River Basin was first examined geologically by Robert Bell almost a century ago in a series of explorations of the major river systems southwest of James Bay (Bell 1877). Other early geological investigations included those of Borron (1890), J.M. Bell (1904), WJ. Wilson (1906), Keele (1920) and McLearn (1927). Recent surveys by the Ontario Department of Mines (Bennett et d. 1967) and the Geological Survey of Canada (Sanford et al. 1968; Craig 1969; McDonald 1969) have significantly improved our knowledge of the geology of the James Bay Lowland. Norris e t al. (1968) have compiled a comprehensive bibliography of all work done in the Hudson Bay Lowland prior to 1967, and no attempt will be made here to review anything but the more recent literature concerning the Precambrian, Paleozoic and Quaternary geology and the search for kimberlite in the Moose River Basin. Useful summaries of the bedrock and surficial geology of the region are given in Stockwell et al., (1970) and Prest (1970). Investigations of the bedrock geology by Bennett e t al. ( 1967) and the Quaternary stratigraphy by Skinner (1973), and a review of diamond exploration in the U.S.S.R. and North America by Satterly (1971) form an essential background to the present study. In particular, the use of alluvial prospecting methods in the search for heavy kimberlite-indicator minerals in northeastern Ontario implies the need for a clear understanding of Quaternary processes and events which moved these minerals from their bedrock source to their present sites of accumulation. Diverse aspects of Precambrian geology, structural geology, Paleozoic stratigraphy, geochemistry, deep crustal geophysics and exploration geophysics all have important implications in relation to the search for kimberlite pipes in the James Bay Lowlands. Many of these aspects are summarized by Satterly (1971) and Brown etal (1967). As early as 1899, a source in the vicinity of James Bay was proposed for the diamonds found in glacial till, soils derived from till, and alluvial gravels in Wisconsin, Indiana and Illinois (Hobbs 1899). Since 1863, a total of 82 diamonds have been discovered in terminal morraine areas of the north-central and mid- western United States (Gunn 1967b). The source of these drift diamonds is somewhat speculative but is commonly considered to be in the Ontario Precambrian Shield (Gunri 1967a; 1967b; 1968; Gold 1968) and more specifically in the area south of James Bay (Brown et al. 1967). Occurrences of kimberlite dikes in Ontario have been described by Satterly (1948), Lee (1965), Lee and Lawrence (1968), and in Quebec by Watson (1955; 1967) and Northern Miner (1968a, b and c). In I960, kimberlite indicator minerals were identified in heavy mineral con centrates obtained from samples of alluvial gravel collected by the Selco Exploration Company in the Moose River drainage basin along the Mattagami, Abitibi, Little Abitibi, Nortjh French, and Moose Rivers (Brown e t al. 1967). Garnets selected from the concentrates on the basis of colour were identified as pyrope-rich (50-80 per cent pyrope) on the basis of their refractive indices (1.72- l .76) and unit cell dimensions (11.539A0 - 11.555A0 ). A total of 13 garnet grains representing 12 sample locations were confirmed as pyrope (Skimming 1960). In 1962, the Canadian Rock Company Limited obtained from the Ontario Department of Mines an exploratory licence of occupation to search for diamonds Heavy Mineral Indicators of the Moose River Basin over a 125 square mile (325 km2 ) area on the Abitibi, Little Abitibi and Bad Rivers in parts of Hobson, Ophir, Valehtine, Heath, Pitt and Wacousta Townships. M. Tremblay of Hard Metals (Canada) Limited collected 25 samples of one cubic foot (0.03m3 ) volume from alluvium in the three rivers. The samples were washed and screened and concentrates were sent for examination to the Central Metallurgical Laboratory of the Anglo American Corporation of South Africa Limited in Johannesburg, South Africa. Eight of the 25 samples contained mauve pyrope in grains from 0.6 to 1.5 mm in diameter and 3 contained magnesian ilmenite grains 0.9 to 1.2 mm in diameter. The pyropes, excepting one grain, were all abraded and nodular and very few were found in any one sample. A single grain of chrome diopside was also identified. No diamonds were found. Lee (1965) sampled the Munro esker from the southwest end of Lake Abitibi to Catherine Township, southeast of Kirkland Lake, a distance of approximately 66 miles (106 km). In a study of glaciofluvial esker transport, over 300 purple garnets, ranging in diameter from 0.5 to 1.23 mm, were found in screened and concentrated samples from 9 sites along the Munro esker, east of Kirkland Lake. On the basis of their refractive indices, unit cell dimensions, and spectrographic analyses, the garnets were identified as pyrope. By comparison with the down-esker displacement distance of concentration peaks for other clasts and heavy mineral components, it was possible to estimate the approximate location of the subcrop source of the pyrope garnets. Subsequently, a kimberlite dike was discovered at the Upper Canada Mine in Gauthier Township (Lee and Lawrence 1968). The kimberlite is Late Jurassic in age, 151 8 m.y. by K Ar on phlogopite (Lee and Lawrence 1968). No diamonds have been recovered from the dike.

PHYSICAL FEATURES

The northwest part of the map-area is underlain by nearly flat-lying Paleozoic sedimentary strata and Quaternary sediments and forms part of the Hudson Bay Lowland. This lowland is a region of very low relief extending inland from James Bay to an elevation of about 500 feet (150 m) above sea level with an average seaward gradient of 3-5 feet per mile (about l meter per km). The major river systems flow northward across this flat, poorly drained coastal plain in roughly parallel courses with a minimum of cross-drainage. The rivers sampled in connection with this project are situated east of the Abitibi and Moose Rivers. They include the Little Abitibi River, French River, Southbluff Creek, Bigcedar Creek and their tributaries, the Bad, Kiasko, Nettogami, Wakwayowkasic and Yesterday Rivers. Recent down-cutting by these rivers through unconsolidated Pleistocene deposits has established steep bluffs from 25 to 100 feet (7.5 to 30m) high and low alluvial banks along the major valleys. The meander scars of early stage modern rivers extend back from present-day valleys for distances of 330 to 5,000 feet (100 m to 1.5 km). The moderately permeable and well-drained soils along the banks and levees of the main river courses support forests of white spruce, balsam fir, trembling aspen, balsam poplar and white birch similar to boreal forest regions further south. Back from the rivers lie immense areas of swamp, bog and muskeg. The extensive blanket of peat and marine clay in the interfluve area has restricted ODM 9007 Photo 1-The James Bay Lowland a poorly drained coastal plain of very low relief covered by an extensive blanket of peat, muskeg and stunted black spruce forest overlying Late Pleistocene fossiliferous marine clay (Tyrell Sea sediments) at the top of a thick Quaternary section. exposure of bedrock and glacial sediments to river-bank sections in the major river valleys. Sphagnum and other mosses, dwarf shrubs and light colored lichens form a dense, continuous cover ranging from about two to fifteen feet in thickness. The vegetation over widespread areas of this ©Archudsonian Swamp© (Tyrrell 1916, p. 8) has a general ©subarctic© appearance because of the prominence of an open woodland of stunted black spruce and tamarack in the muskegs and patterned fens. It is important to recognize that in interfluve areas of thick Quaternary cover, a kimberlite diatreme subcropping less than a kilometer from a major river valley, might not be sampled directly by the drainage system. Given the much greater areal extent of the flat drift-covered interfluve regions, there is a much higher probability that the majpr river systems will sample glacial dispersal fans in Pleistocene till sheets rather than the primary bedrock sources. Low concentrations of kimberlite indicator minerals in alluvial gravels may therefore be an expectable result of the fact that drainage systems are likely to be sampling dilute secondary sources. Southeast: of the Paleozoic-Precambrian boundary, a range of low hills rises to elevations of 700-800 feet (210-240 m) above sea level and trends northeastward from Fraserdale across the eastern part of the project-area. These hills correspond Heavy Mineral Indicators of the Moose River Basin approximately with the area underlain by Precambrian rocks of the Kapuskasing granulite complex. East of the Abitibi River, a substantial amount of bedrock outcrop is exposed along this range of hills. The gradients of the major river systems increase significantly where the north-flowing drainage crosses the Pre cambrian upland. Southeast of Coral Rapids in Wacousta and Kineras Townships, the gradient of the Little Abitibi River is about 24 feet per mile (4.5 meters per km). This upland area extends west and northwest of Fraserdale to include a rolling plateau of sand and silt mapped by Boissoneau (1965) as the Pinard end moraine. Elevations at the top of the Pinard moraine exceed 900 feet (274 m) above sea level and represent the highest elevations in the map-area. South and east of the range of hills that border the James Bay basin, the topography is typical of heavily drift-covered continentally glaciated terrain. Eskers, drumlins and large-scale fluting are the common topographic features in this region. Drainage systems are poorly developed in areas where the uppermost Pleistocene deposits consist of Cochrane till and post-glacial lacustrine sediments. The James Bay Lowland is cool and moist with 720 mm total precipitation per year and a mean annual temperature of 00C. Temperature variations are extreme, with highs in excess of 25 0C in summer and lows of 45 0C in winter. At Island Falls in the south-central part of the map-area, 166 mm of precipitation were recorded during the months of July and August, 1973, compared to the 15-year average of 170 mm for the same July-August period.

REGIONAL GEOLOGY AND GEOPHYSICS

In the summer of 1966 the Ontario Department of Mines conducted a heli copter-supported reconnaissance geological survey (Operation Kapuskasing) of a 28,000 square mile (72,500 km2 ) area extending southward from the vicinity of the Precambrian-Paleozoic contact to latitude 49 000©N and from longitude 79 030©W to 84 000©W (Bennett et al. 1967). In 1967, the Phanerozoic rocks of the James Bay Lowland and the overlying Quaternary surficial deposits were mapped by the Geological Survey of Canada as part of a more extensive air supported geological reconnaissance of the Hudson Bay Lowlands (Operation Winisk) (Sanford et al. 1968). The following abbreviated outline of the regional geology of the Kapuskasing-Moosonee area is intended only to provide background information for presentation of the results of the 1973 survey of heavy mineral indicators and the reader is referred to ODM Preliminary Maps P.370, P.371, P.372, P.373, P.375, P.376, P.396, P.398 and to reports by Bennett et al. (1967) and Sanford et al. (1968) for detailed information on the geology of the project area. The regional geology, magnetics and gravity of the Moose River basin are shown at a scale of l inch to 16 miles (1:1,013,760) in Figures 2 and 3, Chart A, back pocket. The bedrock of the area ranges in age from Early Precambrian to Mesozoic and is covered by unconsolidated sediments of Cenozoic age (Table l, Table of Litho logic Units). Two belts of Archean mafic volcanic, felsic volcanic and sedimentary rocks (Partridge River and Kesagami Lake belts) occur in the northeast part of the region. A large part of the map-area is underlain by biotite-hornblende-quartz- feldspar gneiss and migmatite. These gneisses are presumed to represent rocks of metavolcanic and metasedimentary origin equilibrated within the miHdle to upper 6 Table 1 TABLE OF LITHOLOGIC UNITS FOR THE MOOSE RIVER BASIN AREA (modified after Bennett et al. 1967)

Time Maximum Stratigraphic Formation Lithology thickness Unit (feet) Recent Muskeg, peat, sand, gravel Marine clay, 35 Pleistocene Glacial till, clay, peat 280 Cretaceous Lower Mattagami Fire clay, sand, lignite 170 Upper Long Rapids Bituminous shale, shale 285 Upper and Williams Island Limestone, shale, Middle gypsum 416 Post Ultramafic Lamprophyre, kimberlitic rock U Middle Intrusives O Devonian Upper Fossiliferous limestone 48 o w Middle Abitibi Middle nJ (Moose Limestone, gypsum, shale 254 P- River) Formation Lower Fossiliferous cherty 42 limestone, sandstone Lower Sextant Conglomerate, sandstone, 91 arkose, shale T\lfff\lL-inr\1* *yTFT"\r Middle Silurian and Limestone, dolostone, Upper sandstone —————————————— UNCONFORMITY —— — —— — Z Carbonatite ;5 —————————————— INTRUSIVE CONTACT —————— g Middle and Late 25 Precambrian Diabase U FXTTTTl T TO 11 7t? ^^"VXTT* A rf"**T* w PJ Carbonatite (X Granulite Complex —————————————— FAULT CONTACT ————————— Diabase 2 ;5 Felsic Intrusive Rocks g Early ^ Precambrian Ultramafic Intrusive Age Uncertain Rocks U W ix! o- Migmatite-Metasedimentary-Metavolcanic Gneiss Complex i *CT* A x ff\n nut r* /~f"\'MTr A f~T ,.. .. Metasediments Felsic to Intermediate Metavolcanics Mafic to Intermediate Metavolcanics Heavy Mineral Indicators of the Moose River Basin almandine-amphibolite facies. Exceptionally high grade metamorphic rocks, consisting of magnetite-garnet-hornblende-pyroxene-quartz-feldspar granulite occur in a zone of northeast-trending fault-bounded blocks that traverses the east-central part of the map-area. Structural trends within the granulite zone parallel the northeast-trending long axis of the zone and are obliquely discordant to west- northwest-striking fold axes to the east, and northeast-striking fold axes to the west of the granulite block. The Kapuskasing horst structure has been produced by dominantly vertical uplift along the series of complex, sub-parallel faults that occur within and bordering the granulite zone. Relative uplift along the Kapuskasing structure has brought rocks of pyroxene-granulite metamorphic grade to the same crustal level as epidote-amphibolite and almandine-amphibolite facies rocks im mediately east and west of the fault-bounded block. Limited rock exposures, diamond drilling and aeromagnetic data indicate that the metavolcanic-metasedimentary belts and gneiss complexes of the Moose River Basin are cut by gabbroic to pyroxenitic intrusive rocks of uncertain age. A large gabbroic complex exposed along the Abitibi River and its tributaries to the east and northeast of Fraserdale shows some evidence of primary igneous layering and segregation (Gaucher, 1968). The gabbro is fresh, massive, medium grained and equigranular and contains clinopyroxene, plagioclase (Am?), olivine, biotite, magnetite and apatite (Bennett e t al. 1967). The unaltered and undeformed nature of the intrusion suggests that it may be post-Archean in age. The area east of Fraserdale is covered by thick glacial drift but the aeromagnetic data indicate that the gabbroic complex may subcrop over an area of up to 40 square miles (100 km2 ). Large synorogenic batholiths and satellite stocks of granodiorite, quartz monzonite, and granite intrude the gneiss complex and the metavotcanic-meta- sedimentary 'greenstone' belts in the eastern part of the map-area. Early Precambrian rocks are cut by a north-trending swarm of magnetic diabase dikes that are probably equivalent to the 2485 million year old Matachewan dikes dated by Fahrig and Wanless (1963). The larger diabase dikes show as northerly trending anomalies on aeromagnetic maps. Carbonatite intrustions of two different ages occur in the area. The Clay Howells Complex located 20 miles (32 km) west of Fraserdale in the southwest part of the area is dated at 1,010 million years (K-Ar on biotite), and the Argor and Goldray Complexes situated along faults within the northeast-trending granulite zone have been dated at 1,655 and 1,695 million years (K-Ar on biotite) respectively (Gittins e t al. 1967). Sedimentary rocks of Lower Devonian to Lower Cretaceous age outcrop in the north and northwest parts of the map-area, in the Moose River sedimentary basin. The Moose River Basin is separated from the Hudson Bay Basin by the Cape Henrietta Maria Arch and Paleozoic strata dip southward reaching a thickness of 2,800 feet (850 m) in the vicinity of the Missinaibi River. Ordovician and Silurian rocks along the southern subsurface boundary of the Moose River Basin are abruptly truncated by a major uplifted fault block extending northeastward to Moosonee beneath overlapping Devonian and Cretaceous strata and swinging southeastward along the southern margin of the Quebec embayment (Sanford et al. 1968). The Precambrian basement on the south side of this uplift rises nearly 1,500 feet (460 m) in juxtaposition to rocks of Ordovician and Silurian ages. The subsurface stratigraphic evidence therefore indicates that the time of uplift was post Upper Silurian to pre-late Lower Devonian (Sanford et al. 1968). To the south of 8 this subsurface scarp, the lowermost Paleozoic rocks are clastic terrigenous conglomerates, sandstones and red or grey siltstones and shales of the Lower Devonian Sextant Formation. The uppermost strata of the Moose River basin are Lower Cretaceous beds of the Mattagami Formation which unconformably overlap the various Middle to Upper Devonian formations and rest directly on the Precambrian basement to the west of the map-area along the Mattagami, Opazatika, and Missinaibi Rivers. The clay, sand, lignite and kaolinitic quartz sand deposits of the Mattagami Formation are mainly situated west and northwest of the Abitibi River beyond the area of the present heavy mineral investigation.

Post-Middle Devonian Ultramafic Intrusions

Ultramafic, lamprophyre and 'kimberlite-type* sills and dikes intrude the Lower Devonian Sextant Formation and middle to upper members of the Middle Devonian Abitibi Rivef Formation at Sextant Rapids and Coral Rapids on the Abitibi River (Brown et d, 1967). At Sextant Rapids, a black augite-lamprophyre containing serpentine after olivine, augite, calcite, biotite, fluorite, magnetite and a zeolite mineral, intrudes sedimentary rocks of the Sextant Formation. The conformable lamprophyre sheet is about 60 feet (18 m) thick, extends across the river, and dips gently northward (Brown et d. 1967). The occurrences of lamprophyre and kimberlitic rock at Coral Rapids are described by Brown et d. ( 1967, p.13-16) as follows:

At the head of Coral Rapids, 2 miles [3 km] downstream from Sextant Rapids, a lamprophyre sill about 60 feet [20 m] thick is exposed on the west bank of the Abitibi River and extends along the contact between the Sextant Formation and middle member of the Abitibi River Formation. Megascopically, the lamprophyre is a grey, fine-grained rock with visible phlogopite. In thin section, it consists of phenocrysts of olivine (Fogo), radiating fibrous zeolite (thomsonite) in a very fine-grained, felted ground mass of melilite (?), magnetite, and unidentified minerals. A composite dike composed of lamprophyre and a kimberlitic rock is exposed at the foot of Coral Rapids on the west bank of the Abitibi River and has been intersected by several Ontario Hydro drill holes. The dike is 80 to 100 feet [25 to 30 m] wide, is at least 1,400 feet [430 m] long, strikes N30 0E, and has a vertical dip. The lamprophyre forms the southern half of the dike and is about 100 feet [30 m] wide. About 20 feet [6 m] of the eastern edge of the dike at the river's edge consists of kimber litic rock which appears to intrude the lamprophyre; the contact between the lamprophyre and kimberlitic rock is sharp. The lamprophyre is similar in colour, but is finer-grained, than the Sextant lamprophyre, and in thin section it contains 25 percent serpentinized olivine phenocrysts and rare, zoned, clinopyroxene phenocrysts in a very fine-grained, felted groundmass of clinopyroxene, saponite (?), chlorite, carbonate, magnetite and other unidentified minerals. The kimberlitic rock which is 80 feet [25 m] wide forms the northern part of the dike. Heavy Mineral Indicators of the Moose River Basin

Drill sections show that the dike rises from the Precambrian basement and intrudes more than 50 feet [15 m] of Sextant Formation, 35 feet [10 m] of the middle member and 20 feet [6 m] of the upper member of the Abitibi River Formation. No vertical offset was found along the dike. The kimberlitic rock is pale green, moderately soft, and exhibits a fragmental texture. The fragments form about ten percent of the rock, are rounded dark green microcrystalline basaltic fragments l mm to 2 cm in diameter, xenoliths of rounded, altered granitic basement rocks l to 2 cm in diameter, . . . In thin section the matrix is composed of 12 percent serpentinized clinopyroxene, 3 percent phlogopite, and unidentified zeolite; 10 percent calcite; 8 percent magnetite; 2 percent ilmenite; and 65 percent very fine grained, clay minerals with an olive-green to yellow birefringence. X-ray diffraction studies show that the clay minerals are mainly montmorillonite, with minor amounts of serpentine and chlorite.

A new occurrence of the Coral Rapids-type lamprophyre was discovered intruding highly sheared muscovite-quartz-feldspar gneisses along the Little Abitibi River in south-central Wacousta Township (latitude 50 007'N; longitude 81 023'W). The black, ultramafic rock is apparently dike-like in form, appears to strike ap proximately N300W, and is about 50 feet (15m) wide. The eastern contact of the dike is highly fractured but shows evidence of chilling against the sheared gneissic host rocks. The dike contains sub-rounded xenolithic inclusions of granitic basement rocks ranging from 2 cm to l meter in diameter. It is composed of zoned clino pyroxene phenocrysts in a finer grained matrix of clinopyroxene, plagioclase, serpen tine, olivine, phlogopite, magnetite and carbonate. X-ray diffraction traces of the powdered rock indicate the possible (but unconfirmed) presence of melilite. Frag ments of black, ultramafic rock were first observed in alluvium near sampling site 95 and the dike was discovered by tracing these fragments approximately 500 feet (150 m) in the upstream direction. A chemical analysis of the newly discovered lamprophyre dike in Wacousta Township is compared in Table 2 with (l) analyses of similar dike rocks at Coral Rapids, (2) an analysis of the kimberlite dike at Upper Canada Mines Limited, Kirkland Lake, (3) the average composition of 25 kimberlites from Lesotho, and (4) the average composition of 623 kimberlites from the Yakutian District of Russia. The Wacousta Township ultramafic dike is similar to the occurrences at Coral Rapids and Sextant Rapids in terms of color, texture and mineralogy. The bulk chemistry of the Wacousta dike is generally similar to that of the analysed 'kimberlitic' dike at Coral Rapids, particularly when allowances are made for the differences in FeO/FeaOs ratio, HaO and COs contents. Nevertheless, the diagnostic indicator minerals (pyrope garnet, chrome diopside and magnesian ilmenite) essential to the definition of kimberlite have not so far been identified in these ultramafic dikes. Comparison of chemical analyses of the Wacousta and Coral Rapids dikes with kimberlite compositions shown in Table 2 indicates that the ultramafic dikes on the Abitibi and Little Abitibi Rivers are too high in SiO* and Al2Os and too low in MgO and KoO7Na2O ratio to be properly identified as kimberlite. 10 CHEMICAL ANALYSES OF ULTRAMAFIC DIKES AT CORAL RAPIDS Table 2 AND SOUTH-CENTRAL WACOUSTA TOWNSHIP COMPARED TO KIM BERLITE COMPOSITIONS

ChemicalAnalyses 1 2 3 4 5 6 SiOi 38.90 36.70 35.60 32.7 33.20 27.60 Ti02 2.21 1.61 1.37 2.1 1.97 1.65 A120, 7.88 7.95 11.60 3.2 4.45 3.17 Fe2Oj 4.26 5.67 4.88 3.9 6.78 5.40 FeO 7.68 5.04 7.15 5.8 3.43 2.75 MnO 0.22 0.19 0.20 0.2 0.17 0.13 MgO 16.40 13.80 21.20 31.5 22.80 24.30 CaO 14.70 13.10 7.75 8.1 9.36 14.10 Na20 2.64 0.30 0.16 0.5 0.19 0.23 KjO 0.43 0.67 0.19 2.0 0.79 0.79 HjO± 3.47 8.80 7.85 3.4 10.70 7.89 CO, 2.21 4.08 0.30 5.1 4.58 10.80 P*05 0.79 — 0.36 0.4 0.65 0.55 Total 101.79 97.91 98.61 98.9 99.07 99.36

"Recalculated Analyses SiO2 40.65 43.45 39.58 36.34 39.95 34.46 Ti02 2.31 1-91 1.52 2.33 2.38 2.06 AUO, 8.24 9.41 12.89 3.56 5.35 3.96 FeO* 12.03 12.01 12.83 10.33 11.47 9.50 MnO 0.23 0.22 0.22 0.22 0.20 0.16 MgO 17.14 16.34 23.56 35.00 27.43 30.32 CaO 15.36 15.51 8.61 9.00 11.26 17.60 Na20 2.76 0.36 0.18 0.56 0.23 0.28 K20 0.45 0.79 0.21 2.22 0.95 0.98 P205 0.83 — 0.40 0.44 0.78 0.68 Total 100.00 100.00 100.00 100.00 100.00 100.00

Trace Elements (P.P. M.) Ba 630 650 600 1,900 Co 70 78 Cr 950 1,100 1,100 1,500 Cu 100 56 Ni 440 1,100 Sr 800 1,200 600 790 V 300 600 350 130 Zn 95

Note: Recalculated analyses were obtained by recalculation to 100.0 percent following deletion of H2O± and CO2 and conversion of FeO + Fe2Oj to FeO* (Total Fe as FeO). 1. lamprophyre dike, Little Abitibi River, south-central Wacousta Township, Ontario. Analysis by Mineral Research Branch, Ontario Division of Mines, 1973. 2. Kimberlitic dike, Coral Rapids, Ontario. (Brown tt al 1967, p.18). 3. Lamprophyre dike, Coral Rapids, Ontario. (Brown et al 1967, p.18). 4. Kimberlite dike, Upper Canada Mines Limited, Kirkland Lake, Ontario. (Lee and Lawrence 1968, p. 10, 12). 5. Average composition of 25 Lesotho kimberlites (Gurney and Ebrahim 1973, p. 283). 6. Average composition of 623 kimberlites from the Yakutian District of Russia (Ilupin and Lutz 1971—quoted by Gurney and Ebrahim 1973, p. 283).

11 Heavy Mineral Indicators of the Moose River Basin

The Kapuskasing Gravity High

A remarkable positive gravity anomaly of major regional significance extends northeastward from Chapleau, Ontario along a broad 375 mile (600 km) long linear belt known as the Kapuskasing Gravity High. The axis of this zone of relative positive gravity passes through the town of Kapuskasing in the southwest corner of the project-area and extends northeastward to Fraserdale and beyond to Moosonee. The trend of the Kapuskasing anomaly does not conform with the typical east-west trend of the Archean metavolcanic-metasedimentary belts and intervening gneiss belts of the Superior Province, and the positive gravity field is now widely attributed to large-scale crustal tension leading to (l) crustal thinning and upwarp of the Conrad Discontinuity (Wilson and Brisbin 1965), and (2) crustal fracturing to mantle depth with upward transfer of dense mafic-ultramafic material into the middle and upper continental crust (Innes e t d. 1967). Figure 2 illustrates the close spatial correlations between the Kapuskasing Gravity High, the zone of northeast-striking faults, and the northeast-trending zone of granulite metamorphic grade. The magnetite-rich pyroxene granulites correspond with a linear aeromagnetic high extending north-northeasterly from Fraserdale (Figure 3) and they coincide in a general way with the area of anomalously high gravity outlined by the —10 mgal contour (Figure 2). Alkalic and carbonatite intrusions are closely related to steeply dipping northeast-striking faults within the Kapuskasing horst structure and Figure 2 shows that the Cargill, Teetzel, Clay- Howells, Goldray and Argor Carbonatite Complexes and the Abitibi Canyon Mafic Complex are all coincident with local gravity highs along the Kapuskasing Gravity feature. Mafic, ultramafic and carbonatite intrusions along the Kapuskasing uplift contribute significantly to the positive gravity anomalies but occurrences of heavy metamorphic rocks brought to surface or near surface by repeated uplift along the horst block also contribute a positive component to the regional gravity field. Certainly, the investigations by Gaucher (1968) indicate that a substantial component of the gravity high situated northeast of Fraserdale can be explained by near-surface density contrasts of up to 0.25 g/cm3 between granulite gneisses of mean density 3.04 g/cm3 and the surrounding biotite-quartz-feldspar gneisses of mean density 2.78 g/cm3. The heavy metamorphic and mafic intrusive rocks obviously contribute locally to the positive gravity anomalies over the Kapuskasing structure but a regional analysis of the Bouger anomaly gradient by Innes et al. (1967) indicates that in the vicinity of Kapuskasing, the gravity disturbance can be explained by a source of high density mafic material lying no deeper than 10 to 15 km, and can be accounted for by a local rise of 8 km in the Conrad Dis continuity, changing from a depth of 18 km to 10 km. The present geological and geophysical evidence therefore strongly suggests that the Kapuskasing structural zone is the deeply eroded counterpart of the East African rift valleys and has been the site of major crustal adjustments involving deep level faulting, crustal distension, high heat flow and vertical tectonics over a long time period. These features along with the evidence of alkaline, carbonatite and ultramafic igneous activity and the exposure of granulite metamorphic rocks of exceptionally deep-seated origin have led to comparison of the Kapuskasing structure with the East African and Siberian Rift Systems (Dawson 1964; Satterly 1971), a comparison which, in view of the known occurrences of pyrope 12 garnet indicator minerals in alluvial gravels of the Moose River basin, has invited speculation about the possible existence of kimberlite pipes in the James Bay Lowlands.

QUATERNARY GEOLOGY

Much of the map-area is covered by Quaternary sediments of glacial, glacio fluvial, lacustrine, and marine origin. The average thickness of unconsolidated Quaternary sediments may be in excess of 40 feet (10 m) (McDonald 1969); an abnormal thickness of 700 feet (210 m) has been reported between the Mattagami and Missinaibi Rivers (Hogg, Satterly, and Wilson 1952). In the northern part of the region, interfluve areas are extensively blanketed by poorly-drained peat and marine clay but a fairly consistent Quaternary stratigraphy is recorded in abundant river valley exposures that are commonly as high as 100 feet (30 m) above the present water level. There has been no detailed mapping of the Quaternary sections along the major river valleys where sampling was done during the 1973 field season. However, Skinner (1971, 1973) gives excellent descriptions of stratigraphic sections located immediately west of the project-area along the Abitibi, Mattagami and Missinaibi Rivers. Skinner's work provided a sound base from which to extend studies of the Quaternary stratigraphy in the areas east of the Abitibi and Moose Rivers. In particular, field crews used two sections exposed at the junction of the Missinaibi and Mattagami Rivers as they merge into the Moose River, and a third section near the junction of the Abitibi and Little Abitibi Rivers as reference sections for the recognition of stratigraphic units. Till units from these sections were sampled for use as standards and correlations were made within the present study-area by comparing gross physical and lithological features and relative stratigraphic positions with the standard sections. A composite section showing the sequence of Quaternary rock stratigraphic units and inferred events in the Moose River basin is given in Table 3 (after Skinner 1973). The non-glacial sediments of the Missinaibi Formation that include marine clay and silt strata, peat, and stream deposits, are underlain and overlain by till units over a widespread area of the James Bay Lowlands. In the western part of the Moose River basin along the Missinaibi River, Skinner (1973) has identified at least three tills that pre-date the Missinaibi Formation and are separated by intertill units of silt-clay rhythmites, sand and gravel. The three tills identified as Tills 2,11 and 111 in Table 3 apparently combine to form one pre- Missinaibi till in the area east of the Abitibi River. However, at most exposures along the Mattagami, Abitibi and Moose Rivers, the base of the Missinaibi Formation is below or close to river level so that little of the pre-Missinaibi record is exposed (Skinner 1973). During the present investigation, Quaternary sections on the Little Abitibi River, Bad River, North French River and Bigcedar Creek were examined. No evidence was discovered to support the existence of more than one pre-Missinaibi till unit — referred to in this report as the Lower Till Unit. In the area east of the Abitibi River, the Lower Till Unit is a very hard, highly compacted, silty, calcareous, greenish-grey till transported from a northeasterly direction and containing a high percentage of material derived from Paleozoic 13 Heavy Mineral Indicators of the Moose River Basin

QUATERNARY ROCK-STRATIGRAPHIC UNITS AND INFERRED EVENTS, Table 3 MOOSE RIVER BASIN (after Skinner, 1973)

ROCK-STRATIGRAPHIC INFERRED EVENT AGE UNIT C" years B.P.

weathering; peat and forest growth Terrestrial unit eolian activity stream incision and deposition

Marine unit marine recession marine incursion 7,800

Glaciolacustrine unit glacial retreat

Kipling Till glacial advance

Friday Creek sediments retreat

Adam Till glacial advance

Lacustrine member lacustrine** --. ^ transgression*** -^

Forest-peat member weathering; peat 3 (buried soil) and forest growth g PH > 54,000 S Fluvial member stream incision and deposition z Marine member marine recession marine incursion

glacial retreat

Till III advance

Intertill sediments II-III retreat

Till II advance

Intertill sediments MI retreat

Till I advance 14 strata of the Moose River Basin. Unlike tills derived from crystalline Precambrian rocks, the Lower Till Unit contains very few coarse rock clasts of pebble-size and larger, and is composed mainly of angular sand-grit and silt-sized material. The maximum observed thickness of the Lower Till Unit was about 10 feet (3m). Non-glacial sediments of the Missinaibi Formation overlie the Lower Till Unit and are described in detail by McDonald (1969) and Skinner (1973). The Missinaibi Formation is subdivided from bottom to top into l) marine, 2) fluvial, 3) forest peat soil, and 4) lacustrine members. These members represent respectively l) incursion of the Bell Sea following glacial retreat from the Hudson Bay Lowland, 2) recession of the Bell Sea followed by incision and alluvial terrace development by northward flowing rivers, 3) soil and forest cover develop ment on fluvial deposits, till, and emerged marine sediments, and 4) flooding and formation of a large fresh water lake in front of an advancing ice sheet. The Missinaibi interglacial beds contain wood and peat that is beyond the limit of radiocarbon dating; the age of these beds probably exceeds 54,000 C14 years B.P. Post-Missinaibi deposits lying above the upper lacustrine member of the Missinaibi Formation include from bottom to top 1) Adam Till, 2) Friday Creek sediments, 3) Kipling Till, and 4) late and postglacial sediments (Skinner 1973). East of the Abitibi River, the Adam Till immediately overlies stratified interglacial sediments in numerous excellent exposures along the Little Abitibi and North French Rivers. It is a brownish grey, moderately compact, silty, calcareous till that is up to 10 feet (3 m) thick. Till fabric data and striations on boulders in and at the base of the Adam Till have been plotted by Skinner (1973) and are shown in Figure 4. These limited data indicate that the ice sheet which deposited the Adam Till flowed from about N40 0E, possibly from a dispersal center in western Labrador. The break between the Adam Till and the Kipling Till is marked by a poorly stratified sandy to gravelly ablation till, glaciofluvial sediments, or in some cases by a boulder pavement. West of the project-area, in exposures along the Abitibi River, Friday Creek, Adam Creek, and Opasatika River, Skinner (1973) has mapped deposits of nonglacial, loose, medium- to fine-grained cross-stratified sand and silt-clay rhythmites at this stratigraphic level and has informally named this unit the Friday Creek sediments. The uppermost till unit of the region has been described by Skinner (1973) as far south as Smooth Rock Falls and is probably correlative with the Cochrane Till farther south (Hughes 1965; Boissonneau 1966). In the area north of the Pre- cambrian-Paleozoic contact, the upper till is named the Kipling Till after the type locality on Adam Creek in Kipling Township (Skinner 1973). Regionally, the Kipling Till is recognized by its brown to brownish grey color, low compaction relative to older tills, and its stratigraphic position. Ice-flow directions determined from striations on boulders at the base of the Kipling Till appear to be similar to directions inferred from ice-flow features (glacial fluting) on the Cochrane Till plain south of the Precambrian-Paleozoic boundary (Skinner 1973, p.35). The Kipling and Cochrane Tills may therefore have been deposited during the same glacial re-advance. The youngest Pleistocene strata in the Moose River Basin comprise late-glacial lacustrine deposits, fossiliferous marine sediments deposited in the post-glacial Tyrrell Sea, and terrestrial deposits of peat, alluvium and eolian sand formed after post-glacial isostatic rebound caused emergence of the land surface. 15 Heavy Mineral Indicators of the Moose River Basin

LEGEND J T& Striations on boulders in base tiff.

T Till fabric.

Miles O 5 10 15 20 25 30

O TO 20 30 4050 Kilometres

SMC 12987

Figure 4-Direction of ice-movement for Adam Till.

16 ODM 9008 Photo 2-Thin deposits of (1) stratified clay-silt sediments of the Barlow-Ojibway deposit, (2) Cochrane Till, and (3) post-Cochrane clay; all overlying cobbly esker gravels and thinning toward the esker crest at the right side of the photograph.

South of the Precambrian-Paleozoic boundary, good exposures of Quaternary sediments that would facilitate correlation of sections in the Moose River Basin (McDonald 1969, 1971; Skinner 1973) with sections in the Kapuskasing- Cochrane area (Hughes 1965; Boissoneau 1966) are not abundant. Consequently, there is little direct evidence to establish stratigraphic correlations between the north and south parts of the project-area. In the southern part of the region, the basal Pleistocene consists of glacial till and associated glaciofluvial and esker deposits overlying the Precambrian basement. The till is a pale grey, moderately compact, stony till composed of abundant large boulders and cobbles in a silty sand matrix (Hughes 1965), and deposited by ice flowing in a general southerly direction. The ratio of Precambrian to Paleozoic clasts increases and the carbonate content of the till decreases southward with increasing distance from carbonate-rich source rocks in the James Bay Lowland. Glaciofluvial deposits ranging from fine sand to coarse gravel occur mainly in north-trending esker ridges lying on lower till or Precambrian bedrock. A large terminal moraine complex centered in Pinard Township and named the Pinard Moraine by Boissoneau (1966) forms an east-trending ridge approximately 17 Heavy Mineral Indicators of the Moose River Basin

60 miles (100 km) long between the Little Abitibi River and the Mattagami River. Locally bedded deposits of medium- to fine-grained sand rising up to 175 feet (50 m) above the surrounding terrain have been overriden by the late Pleistocene re-advance of the Cochrane ice sheet and are unconformably capped by 3 to 15 feet (l to 5 m) of clay till. Varved glaciolacustrine clay-silt sediments of the Barlow-Ojibway Formation (Hughes 1965) lie above the lower till and cover a widespread region of north eastern Ontario and northwestern Quebec within the basin of glacial lake Barlow-Ojibway; a large preglacial lake that existed between the Hudson Bay-St. Lawrence drainage divide and the front of a northward retreating ice sheet. The Barlow-Ojibway sediments are overlain by the Cochrane Till sheet; a brown to grey-brown, calcareous clay till deposited during a late glacial re-advance that overrode varved sediments of glacial Lake Ojibway. Movement of the Cochrane ice sheet consisted of a fan-shaped advance over the area and in general, the trends of drumlinoid landforms and surface fluting observable on air photographs vary from northeast in the southwestern part of the area to north in the south-central part and northwest in the southeastern corner. At several localities, and particularly to the south and east of the Pinard Moraine, younger fresh water lacustrine sediments lie above the Cochrane Till. The pre-Barlow-Ojibway eskers have been overridden by the Cochrane re-advance and are identifiable as topographic features only in the southern half of the map-area, where they are commonly recognizable even when covered by a thin veneer of varved sediment or Cochrane Till (Photo 2).

INVESTIGATION OF HEAVY MINERALS

The Search for Kimberlite Indicators Sampling and Gravity Concentration of Heavy Minerals

Field work carried out during 1973 in the Kapuskasing-Moose River area was mainly designed to outline the distribution and patterns of dispersal of diagnostic kimbe^lite-associated heavy minerals in Recent alluvial sediments and in Pleistocene deposits of glacial and glaciofluvial origin. Generally similar procedures were employed to recover heavy mineral concentrates from material obtained from: 1) Recent alluvial deposits, 2) river bank exposures of Lower Till and Adam Till, 3) pits excavated along esker nodes and crests, and 4) pits excavated in Kipling- Cochrane Till at locations where esker material could not be reached at a depth of 5 feet (1.5 m). In each case, large bulk samples were reduced to 4.5 litres at the field collection site by using specially constructed 17 inch (43 cm) diameter stainless steel screens with aluminum frames to isolate material in the 0.5 mm to 1.23 mm size interval, the optimum particle size range for efficient gravity recovery of the kimberlite indicator minerals. Sample site locations and sample identification numbers are plotted on the Geological Map (back pocket). Each sample type is identified by a separate symbol. 18 ODM 9009 Photo 3-On site screening of alluvial sand and gravel collected from natural riffles in the river bed where heavy minerals are concentrated.

Samples of coarse sand and gravel alluvium were collected from riffled gravel bars spaced at intervals of 2 to 8 miles (3 to 13 km) along the major north- flowing drainage systems between longitude 80030'W and the Abitibi River. Samples were collected from areas of maximum natural heavy mineral concentra tion in riffled parts of the river beds around and under boulder and cobble-sized material. At low water levels during July and August, it was generally possible to make helicopter landings at suitable sampling sites on mid-river bars. Approxi mately l to 5 cubic feet (28 to 140 litres) of sand and gravel material was wet screened on site in the river to produce a 4.5 litre sub-sample of the 0.5 to 1.23 mm size fraction. Depending on the size distribution of the source material, the sampling and sieving of each sample took from Yz hour to 3 hours. To test the possible inflow of kimberlite indicator minerals into the present-day drainage systems from secondary sources in the Quaternary deposits, heavy minerals were investigated in bulk samples collected from till sheets underlying and overlying the Missinaibi interglacial beds. Where present, the Lower Till overlies the bedrock and its heavy mineral assemblage is more or less diagnostic of the subsurface bed rock in the up-ice direction. For the most part, the Adam Till overlies interglacial beds of the Missinaibi Formation and only locally rests on the pre-Quaternary bedrock surface. Its heavy mineral assemblage may therefore have been derived 19 Heavy Mineral Indicators of the Moose River Basin mainly from re-worked sedimentary material deposited during the Missinaibi interval. For purposes of .locating and tracing mineralogical peculiarities of the drift-covered bedrock, the Lower Till is the preferred sampling medium. The Lower Till was sampled at 6 locations on the Little Abitibi River, Bad River, Bigcedar Creek, North French River and South Bluff Creek. Adam Till was sampled at 6 sites on the Little Abitibi River, Bad River, North French River, Kiasko River and Wakwayowkastic River. Both tills are calcareous and compact — the Lower Till especially, is extremely hard and highly compacted. They contain a large component of fine sand, silt and clay material below the 0.5 mm to 1.23 mm size interval from which the heavy minerals were recovered. It was therefore necessary to crush, pulverize, and screen large volumes of till at the field site in order to recover the correctly sized 4.5 litre sample required for gravity recovery of heavy minerals. The procedure frequently took 3 to 6 hours per sample. Esker sediments were sampled only in the southeast and extreme southwest parts of the project-area in regions where older units of the Missinaibi Formation and pre-Missinaibi tills are discontinuous or more generally absent. South of the Precambrian-Paleozoic boundary, eskers deposited by south to southeast flowing subglacial streams during the main Wisconsin glaciation have been overridden by the Cochrane re-advance and modified by wave action and sedimentation in post glacial lakes. The pre-Barlow-Ojibway eskers nevertheless remain recognizable as elevated linear topographic features on the Cochrane till plain, even when covered by up to 10 feet (3m) of younger till or lacustrine sediment. At intervals of ^ to 4 miles (0.8 to 6 km) along the esker ridges, samples of massive gravel were collected near the crest and on the upstream edges of esker nodes or beads that occur intermittently along the medial ridge of the esker train and tend to be coarsest gravel. At each site, a pit was excavated to expose the massive esker gravel and a sample of the 0.5 mm to 1.23 mm size fraction was obtained by screening the gravel. The samples were transported to the field base camp where they were further processed by a gravitation procedure. The gravitate technique is extensively used in diamond exploration programs and is a rapid method of making a heavy mineral concentrate from a uniform size-feed bulk sample. The 4.5 litre sample is dumped into a specially designed 17 inch (43 cm) diameter sieve. The size of the sieve opening is less than the 0.5 mm minimum particle size in the screened material so that the sample is retained in the aluminum screen. The screen is carefully maintained in the horizontal plane and the sample is gently agitated underwater using a vertical jigging motion. This procedure eventually produces a relatively clean, circular bullseye concentrate of heavy minerals at the bottom of the sample and in the central part of the screen (Photo 4). The ratio of concentration is about 100:1. Concentrates obtained by overturning the gravitate screen and skimming off the heavy mineral bullseye, were shipped to laboratories of the Ontario Division of Mines, Mineral Research Branch in Toronto. As each sample was received, it was weighed and screened through #10 (2.00 mm) and #30 (0.595 mm) sieves to remove minor amounts of extremely fine or coarse material. The screened sample was weighed and placed in a separatory funnel containing methylene iodide (S.G. = 3.3) diluted with acetone to a specific gravity of 3.1. The gravity of the 20 OOM 9010 Photo 4-Bullseye of heavy minerals concentrated by gravitation at the center of the sample and overturned out of the gravitate screen. liquid was checked after every second separation and corrected as required. Standard procedures for heavy liquid separation were followed and the heavy and light fractions were washed thoroughly with acetone. Both fractions were dried on filter paper and the heavy fraction was weighed prior to examination. The weight of the heavy mineral fraction varied widely (see Table, Appendix A) ranging from 0.26 g in sample KT193 to 210.31 g in sample 89. In a general way, the amount of heavy minerals recovered from material in the 0.595 mm to 2.00 mm size range is a function of sediment type and source material. From the data listed in Appendix A, average heavy mineral contents were calculated for each sediment type as follows: Lower Till — 3.88 g; Adam Till — 2.29 g; Kipling- Cochrane Till — 2.54 g; Eskers — 7.34 g; Alluvium — 27.52 g. These averages reflect 1) differences in the heavy mineral content of Precambrian, Paleozoic and Quaternary source rocks, 2) differences in the ability of glacial, glaciofluvial and alluvial processes to concentrate high density minerals, and 3) postglacial weathering processes which move less resistant material into finer sizes. Large amounts of garnet and magnetite enter the north-flowing drainage systems as they cross metamorphic rocks of the Kapuskasing structure. High concentrations of these minerals occur in the 0.595 mm to 2.00 mm size fraction of alluvium collected from the Little Abitibi, Bigcedar, and North French systems at locations where these rivers are eroding granulite grade metamorphic rocks of the Kapus kasing zone. These rivers receive high levels of heavy mineral input as they traverse the Precambrian upland southeast of the Moose River Basin. In comparison, heavy minerals are much less abundant in alluvial deposits derived from Paleozoic and Quaternary formations in areas where erosional input from the Precambrian basement rocks is minimal. 21 Heavy Mineral Indicators of the Moose River Basin

Samples of till derived from l) Paleozoic sediments of the James Bay Lowland, 2) interglacial sediments of the Missinaibi Formation, and 3) postglacial lacustrine clays of the Barlow-Ojibway Formation, contain significantly lower concentrations of heavy minerals in the 0.595 mm to 2.00 mm size range.

Laboratory Examination of Mineral Concentrates

The heavy fraction of the sample was placed at one end of a deep Pyrex dish. Small portions of the sample were swept into the center of the dish and spread out to obtain a single layer of grains. The grains were then systematically examined under a low-power binocular microscope. In early stages of the study, the mineral grains were immersed in water and were examined using artificial transmitted illumination from a light source placed underneath the Pyrex dish. It was later discovered that equally good colour distinctions could be achieved by examination of dry mineral grains under medium-intensity artificial reflected illumination, or in some cases natural light. In this way, the entire heavy fraction of each of the 143 samples (20 till, 38 esker, 85 alluvium) was carefully examined. All samples were systematically examined two or more times, it is estimated that over 2 million grains were examined. The heavy fractions of the samples, no matter what their origin (esker, till or alluvium) contained generally the same minerals. The relative amount of each mineral present varied somewhat, but not enough to categorize a sample as to its origin or location. Most samples contained from about 10 to 50 percent garnet. The other common minerals were hornblende, epidote, sphene, pyroxene, apatite, magnetite, limonite, hematite and lithic fragments. Brief observations on the mineralogy of the individual heavy mineral fractions are tabulated in Appendix A with special emphasis on the nature of the garnets and the occurrence of unusual minerals. A few samples were observed to have relative large amounts (more than a few grains) of the following minerals: Sample No. Mineral Sample No. Mineral AT19 Pyrite 79 Pyrite AT26 Pyrite 80 Pyrite, Chalcopyrite 33 Euhedral Barite 86 Pyrite 43 Limonite 102 Euhedral Apatite 44 Pyrite 103 Euhedral Apatite LT66 Pyrite E272 Euhedral Staurolite Angularity of grains was a dominant feature of all the heavy mineral fractions. Well rounded grains were a rarity and these included only limonite and a few garnets. Of the rounded garnets, a very few were identified as pyrope. The light fraction also had little variation in mineralogy from sample to sample. Quartz was generally the dominant mineral .In most cases, either limestone or feldspar occurred abundantly after quartz, but the presence of one seemed to almost preclude the presence of the other. The remainder of the sample usually contained red and/or black shale, fossils and assorted lithic fragments. Quartz 22 ODM 9011 Photo 5-Mineralogy of heavy mineral fraction (x 7).

1. Euhedral garnets 2. Angular garnets 3. Apatite 4. Hornblende 5. Pyrite 12 6. Pyritized fossils 7. Magnetite 8. Epidote 9. Marcasite 10. Limonite 11. Lithic fragments 12. Quartz 13. Pyroxene 14. Hematite 15. Sphene

23 Heavy Mineral Indicators of the Moose River Basin

grains varied from angular to very well rounded and spherical. Feldspar grains and limestone and shale fragments were all generally well rounded.

Mineralogy and Chemistry of the Kimberlite Indicator Minerals

Because garnet is physically and chemically resistant to weathering, it is relatively abundant in the heavy mineral fraction of unconsolidated material. It is also readily distinguished from other minerals. The rare variety, pyrope, can usually be differentiated from ordinary garnet by a tinge of purple colouration to its usual pink or red. The refractive index can be used for making a more positive identifica tion. Ilmenite and diopside are not so easily identified as garnet. A number of silicates of varying shades of green were noted and those suspected of being chrome diopside were selected for analysis of their chromium content by electron probe. Suspected magnesian ilmenite grains with a black shiny subvitreous lustre were likewise selected for analysis of their magnesium content. In choosing the two mineral types, there was not the same degree of certainty that they were indeed diopside and ilmenite. This was borne out in the analyses which indicated epidote, rutile and hematite, as well as the two minerals sought. In all, 143 samples were examined. Procedures were modified with experience and as a result most pyrope was found on the second examination of the samples. The main procedural change consisted of looking for shape as well as colour in the garnets. In so doing, more attention was directed to garnets that were well rounded (see photos 6 Se 7). With one exception, all the pyrope was of this shape; however, we did not neglect to check numerous angular fragments resembling pyrope. In contrast to the smooth-surfaced pyrope, pyroxene and ilmenite grains selected for electron probe analyses were relatively angular. The latter minerals were chosen on the basis of their colour and lustre. During the course of examination, the possibility of economic minerals was kept in mind and any unusual minerals were noted. Grains of suspected pyrope, chrome diopside, and magnesian ilmenite were removed for further examination and analysis. Garnets suspected of being pyrope were checked in a liquid with a refractive index of 1.76 as the index of pyrope is below this while all other garnets have an index higher than 1.76. The refractive index of the garnet was checked by placing the grain in a small glass cup filled with index liquid and observing the whole grain under the petrographic micro scope. This method permits retention of all pyrope garnets after they have been identified. All mineral analyses were made with an ARL-EMX electron microprobe using an accelerating potential of 15 kilovolts and a sample current of 0.03 microamperes. Beam diameter was approximately l micron. Integration time was about 10 seconds for all elements. Beam current integration to compensate the instrumental drift was used throughout the analyses. The data have been processed through the program EMPADR (Rucklidge 1967). With this computer program, there was a minimum of manual data manipulation required, since results could be fed to the computer in the form and order in which they accumulated during analysis, being automatically sorted and 24 ODM 9012 Photo 6-Well rounded garnets the grain closest to the scale is almandite; the others are pyrope (x 22).

ODM 9013 Photo 7-Angular fragments of pyrope front the Upper Canada Mine with garnets shown in Photo 6 (x 22). 25 Heavy Mineral Indicators of the Moose River Basin

processed to give the chemical analysis. The mineralogical compositions were calculated from the molecular concentra tions.

GARNET

The majority of the garnets were angular and of no particular shape. Euhedral garnets were found occasionally and these were usually mauve (filled with in clusions) or deep red. Although garnets were found in a wide range of colours — red, pink, orange, brown, mauve and purple, the most common colours by far were pale pink and brown. Orange and mauve ranked next with deep red and purple being the least common. The refractive index of garnets of all colours (except the purple) was usually well above 1.76. Well rounded garnets were rare. They were found in all colours, but most commonly were pink. A sample would contain at the most, a dozen rounded garnets but often there were less. A small number of these were identified as pyrope. These rounded garnets were generally smaller in size than the average angular garnet (see photo 8). The average diameter of the pyropes was about 1mm. Twenty grains of pyrope garnet were identified in twelve samples distributed as follows: No. of Pyrope Source of Sample Sample No. Grains Sample Type Little Abitibi River 78 2 Alluvium 79 l 94 l Bad River 86 l 88 l Big Cedar Creek 70 l North French River 33 l 44 5 266 2 Wakwayoukastic River 28 l " 22 2 Esker E199 2 Esker Gravel All of the pyrope grains excepting one angular grain from sample No. 22 were unusually well rounded and approximately spherical in shape, a feature which contrasted strikingly with the general angularity of other minerals in the heavy mineral concentrates. These well rounded pyrope grains have the appearance of highly abraded material normally interpreted as evidence for long distances of clastic transport. However, it is important to stress here that pyrope garnets in kimberlite occur not as angular grains but as spherical nodules. Because kimberlite- associated pyropes are already partially rounded at the primary source, roundness and sphericity cannot be confidently used to estimate the distance of secondary transport by alluvial or glacial processes. The single pyrope grain that was angular in shape occurred along with one that was well rounded (in sample 22). 26 ODM 9014 Photo 8-lllustration of size difference between angular and rounded garnets (x 16).

f r*-i

ODM 9015

Photo 9-Pyrope garnets (x 22). 27 Heavy Mineral Indicators of the Moose River Basin

ELECTRON MICROPROBE ANALYSES AND CALCULATED MOLECULAR Table 4 COMPOSITIONS FOR 10 PYROPE GARNETS FROM THE MOOSE RIVER BASIN COMPARED TO AN ANALYSIS OF PYROPE GARNET FROM THE TANZANIA DIAMOND FIELDS Sample No. Tanzania 70 94 199 86 78 33 266 28 199 44 SiOz 41.83 42.35 41.29 41.92 42.27 41.51 41.66 41.38 41.61 42.02 41.51 TiOz 0.09 0.03 0.08 0.05 0.04 0.50 0.80 0.26 0.29 0.15 0.11 A120, 20.15 20.41 19.64 22.93 20.40 20.89 21.02 21.18 20.34 19-91 19.76 Cr20a 3.12 5.10 4.18 4.44 4.16 3.86 3.46 4.20 6.17 2.27 4.16 FeO 9.02 7.57 7.57 8.38 8.22 6.82 6.89 6.85 6.84 8.79 7.81 MnO 0.40 0.63 0.60 0.46 0.46 0.30 0.28 0.32 0.40 0.56 0.46 MgO 20.15 17.97 17.38 19.60 19.55 20.07 19.10 19.43 20.19 18.43 20.70 CaO 5.46 5.57 5.63 5.59 5.63 4.48 4.78 4.70 4.37 4.77 5.68 Total 100.22 99.63 96.37 103.37 100.73 98.41 97.99 98.31 100.21 96.90 100.19 Si 6.015 6.105 6.148 5.838 6.037 6.004 6.046 5.998 5.952 6.204 5.968 Al 3.415 3.467 3.448 3.764 3.434 3.561 3.596 3.619 3.430 3.464 3.349 Cr 0.355- 0.581- 0.492- 0.488- 0.470- 0.441- 0.397- 0.482- 0.698- 0.265- 0.473- 4.00 4.05 3.95 4.26 3.97 4.06 3.99 4.13 4.16 3.75 4.00 FC+* 0.220 — — — 0.062 — — — — — 0.166 Ti 0.010 0.003 0.009 0.006 0.004 0.054 0.087 0.029 0.031 0.016 0.012 Mg 4.319 3.862 3.858 4.068 4.163 4.326 4.132 4.198 4.305 4.057 4.436 Fe+z 0.865- 0.912- 0.892- 0.976- 0.920- 0.825- 0.836- 0.830- 0.818- 1.085- 0.773- 6.08 5.71 5.72 5.93 6.00 5.88 5.75 5.80 5.84 5.97 6.14 Mn 0.049 0.077 0.075 0.054 0.056 0.037 0.035 0.039 0.049 0.070 0.056 Ca 0.842 0.860 0.899 0.834 0.861 0.694 0.743 0.729 0.670 0.754 0.874 Almandine 14.2 16.0 15.6 16.5 15.3 14.0 14.5 14.3 14.0 18.2 12.6 Andradite 5.0 — — — 1.6 — — — — 2.4 Grossular — 0.8 3.6 2.6 1.0 0.9 4.2 0.8 — 5.5 — Pyrope 70.4 67.5 66.8 68.4 69.3 72.2 70.6 71.4 73.7 67.4 72.2 Spessartine 0.8 1.3 1.3 0.9 0.9 0.6 0.6 0.7 0.8 1.2 0.9 Uvarovite 8.9 14.3 12.1 11.5 11.8 10.9 10.0 11.7 11.5 7.1 11.8 Total 99.3 99.9 99.4 99.9 99.9 93.6 99.9 98.9 100.0 99.4 99.9 Remainder 0.033 FC+ 8 0.053 Fe-p 0.039 0.006 0.037 0.017 0.005 0.081 0.061 0.057 0.220 0.033 0.006 Mg Mg Mg Mg Mg Mg Mg Mg Cr Mg Si 0.042 0.006 0.037 0.006 0.006 0.084 0.006 0.066 -0.252 0.037 -0.079 Si Si Si Si Si Si Si Si Al Si Al

Sample No. Latitude Longitude 70 50021' 81014' 94 50010' 81027' 199 50003' 80049' 86 50016' 81018' 78 50029' 81023' 33 50047' 80057' 266 50017' 81006' 28 50017' 80040' 199 50003' 80049' 44 50039' 80059' 28 Colour varied considerably within the group of 20 pyrope garnets. Some were an intense reddish purple, others were pinkish red-purple, while one or two were pale pink or pale red with just a tinge of purple. A few pyropes contained tiny, black needle-like inclusions. All of the garnets identified as pyrope by binocular microscope examination had an index of refraction of 1.76 or less, conforming with data summarized by Brown et al. (1967, Figure 6, p.24) for garnets from kimberlite and non- kimberlite sources. The chemical compositions of 10 of the 20 garnets were determined by electron probe analysis and the results are shown in Table 4 where chemical and molecular compositions are compared with an analysis of a pyrope garnet from the diamond fields of Tanzania. These data show the pyrope molecule to be high (in the range of 66.8 to 73.7 percent) in all of the analyzed garnets and confirm the identification of pyrope in heavy mineral concentrates from the Moose River Basin.

DIOPSIDE

Fifteen grains selected from the heavy mineral fractions were analyzed for CaO, MgO and CraOa in an effort to identify chome diopside. Four of the samples proved to be epidote, three were non chromium-bearing diopside and eight were diopside with a chromium content ranging from 0.09 to 0.57 per cent (CraOs). Dana (1966) suggests that a chrome diopside should contain more than one percent chromium. Chemical data for the 8 chromium-bearing diopsides are given in Table 5. The appearance of these chromium-bearing diopsides was not distinctive. Only four of the eight grains displayed some cleavage and the colour of all the grains varied from light to dark green and olive. One grain appeared to display some internal reflection. Only one of the chromium-bearing diopsides was found at a sample location where pyrope was also found (No. 79). The others were quite randomly distributed over the project area; some close to pyrope locations and others not.

TOM* R PARTIAL CHEMICAL ANALYSES OF CHROMIUM-BEARING DIOPSIDE i aoie o GRAINS FROM HEAVY MINERAL CONCENTRATES

Diopside Sample 152 14 39 27 89 48 79 43 (pure)

CrjOj 0.57 0.49 0.29 0.27 0.24 0.11 0.10 0.09 — CaO 23.18 22.29 18.68 23.78 22.51 23.01 23.77 22.57 25.9 MgO 16.84 16.97 18.33 17.74 17.91 16.69 17.24 15.99 18.5

Electron Microprobe Analyses by A. Tuemer, Mineral Research Branch, Ontario Division of Mines, 1973. 29 Heavy Mineral Indicators of the Moose River Basin

CHEMICAL ANALYSES OF ILMENITE GRAINS FROM HEAVY MINERAL Table 6 FRACTIONS OF SAMPLES 40 AND 89

Ilmenite Sample No. 89 89 40 89 89 (pure)

FeO 33.61 44.87 65.23 46.76 47.26 47.3 MgO 12.04 2.43 2.27 1.59 0.34 TiOi 53.85 54.70 27.99 52.15 52.67 52.7 Total 99.50 102.00 95.49 100.50 100.27

Electron Microprobe Analyses by A. Tuemer, Mineral Research Branch, Ontario Division of Mines, 1973.

ILMENITE

Analysis for MgO, FeO and TiO2 was performed on fourteen selected grains of suspected ilmenite in an attempt to identify magnesian-ilmenite. Two of the grains proved to be rutile, six were not ilmenite and the remaining six were ilmenite with a magnesia content ranging from O to 12.04 percent (see Table 6). Deer, Howie and Zussman (1962) state that "considerable substitution of magnesium for ferrous iron can take place leading to the end member MgTiOa, geikielite." All grains selected for this analysis were similar in appearance: black in colour, somewhat rounded and with a subvitreous lustre. Only one of the grains analyzed contained enough magnesia to place it in the magnesian-ilmenite category. This grain, containing 12.04 percent magnesia, was found at sample location No. 89, immediately upstream from a sample location where pyrope was found (No. 88).

THE SOURCE OF KIMBERLITE INDICATOR MINERALS

Distribution of Pyrope Garnets in the James Bay Lowland

Most of the sample locations where pyrope was found were northwest of (i.e. downstream from) the Kapuskasing granulite horst block; however, two sites were located within the granulite, and for the first time, pyrope was recognized at locations (No. 28 and No. E199) southeast of the Kapuskasing structure. The 12 sites of pyrope discovery connected with this work were combined with information from previous surveys by Skimming (1960) and Tremblay (1963) to show the 30 distribution of all reported occurrences of pyrope garnet (Geological Map). The 3 separate surveys have identified a total of 53 pyrope grains at 32 different locations, mostly in the area between the Kapuskasing horst block and the Moose River. Over half of these (30 pyropes from 19 locations) occur within the drainage system of the Little Abitibi River, although this may be a reflection of the fact that the Little Abitibi drainage has also been the most extensively sampled. A second area of pyrope concentration (9 grains at 5 sites) occurs along a segment of the North French River immediately north of the Precambrian-Paleozoic contact. More detailed sampling of alluvium in parts of the Moose River Basin might outline more conclusively the distribution of kimberlite subcrop localities, but the available data suggest that kimberlitic source rocks are likely to occur along the north margin of the Kapuskasing horst block, either in Precambrian granulites of the Kapuskasing block itself, or in overlapping Paleozoic strata.

Reconstruction of Pyrope Transport History in Quaternary Time

The reconnaissance level of current geological mapping in the Moose River Basin (Bennett et al. 1967) cannot completely rule out the possibility that pyrope- bearing kimberlite exposed in active river channels may be contributing directly to the heavy mineral input of the river systems. The discovery in 1973 of a new occurrence of the Coral Rapids-type lamprophyre crossing the Little Abitibi River in south-central Wacousta Township was confirmation that kimberlite diatremes of similar size might occur as yet unrecognized along the major river courses. Nevertheless, the level of pyrope in samples of alluvium is extremely low; generally not exceeding 2 grains per 4.5 litre sample. These low concentrations in alluvial gravels suggest that the rivers may be sampling an already dilute source of garnets. In the drift-covered interfluve areas, a kimberlite diatreme subcropping less than a kilometer from a major river valley, might not be sampled directly by the drainage system. Given the large areal extent of the flat interfluve regions, there is a much higher probability that the major river systems will sample glacial dispersal fans in Pleistocene till sheets rather than primary bedrock sources. Low concentrations of kimberlite indicator minerals in alluvial gravels may therefore be an expectable result of the fact that drainage systems are likely to be sampling already dilute secondary sources. It seems more than likely, therefore, that the pyrope garnets have not had a straightforward journey to their points of discovery, and that they were carried in a number of directions by successive stages of glacial, glaciofluvial and alluvial transport. Therefore, the prospects of tracing back the pyropes by conventional methods of upstream search are not encouraging. A multiple choke analysis of the routes by which the pyrope garnets could have reached their points of discovery confirms the probability of secondary sources or of multistage transport. So far, no kimberlite indicators have been discovered in samples of till and it is not possible to know with certainty whether or not the heavy minerals have been reworked from one till to another. In addition to the uncertainties about directions of transport, there remains the problem of distance of transport. Criteria of roundness and sphericity cannot be used with any confidence to estimate the 31 Heavy Mineral Indicators of the Moose River Basin transport distance of nodular garnets from kimberlite sources, and in the case of alluvial minerals, the reconstruction of Quaternary transport patterns is further complicated by Recent north-flowing drainage which reverses the direction of earlier transport by glacial inflow from the north to northeast. The record of Quaternary events in the Moose River Basin is evidence that heavy minerals from subsurface kimberlite sources may have undergone extensive reworking and multistage transport. Nevertheless, the low levels of pyrope con centration in alluvium along the Little Abitibi and North French Rivers can be adequately explained by alluvial transport of pyrope mineral grains derived from a dispersed secondary source in till sheets deposited by ice advancing from the north east quadrant. Both the Lower Till and the Adam Till were deposited by south westerly advancing glaciers which might have plucked material from kimberlite bedrock located up-ice (i.e. northeast) from the north-flowing present-day drainage systems. It is therefore suggested that kimberlite indicator minerals discovered in the present-day drainage sediments are derived from glacial dispersion fans related to kimberlite subcrop located to the east of the Little Abitibi River and the North French River. Without some geophysical guidelines to restrict the search to relatively small areas, a slow and costly program of drift tracing will be required to identify the location of pyrope-bearing glacial fans in tills exposed along these river valleys.

Airborne Geophysical Exploration for Kimberlite

The possibilities of narrowing the kimberlite target areas by aerial magnetometer surveys have been examined by Edwards and Gratton-Bellew (1969), and the following is an extract from their report. Aerial magnetometer survey seems to be the only technique which might have some chance of success, but with the currently available equipment and techniques the chances of discovering a kimberlite pipe by this method do not seem too good. The Russian kimberlites produce anomalies of about 1,000 gammas, when they outcrop at the surface. A cover of 5 metres of unconsolidated material reduces the anomaly to about 500 gammas, this latter figure possibly represents the sort of values which might be expected over kimberlites, covered by a thin layer of glacial or marine deposits, in the James Bay Lowlands. The average size of the larger kimberlite pipes is about 500 feet [150 m] diameter so the geophysical target might be an area about 600 feet [180 m] in diameter with a value of about 500 gammas. The closest flight line spacing that is practicable is one-eighth mile (660') [200 m] and in practice a 1,000 foot [300 m] spacing might be the best obtainable. In either case a kimberlite could well lie between two lines and hence go undetected. There is also the question of whether an area of length 600 feet [180 m] with a value of 500 gammas could be detected, this would depend to some extent on the magnetic intensity of the background. In the James Bay Lowlands, the complex magnetic signature found in most Pre-cambrian shield areas is simplified by the blanketing effect of the 32 Paleozoic sediments and so the prospects of detecting anomalies due to kimberlite is better, but still very poor. If it is ever intended to prospect large areas for kimberlites by means of aerial magnetometer surveys, serious thought should be given to improving the equipment and techniques which are used in aerial surveying. (P. Gratton-Bellew). The project-area is covered by Geological Survey of Canada-Ontario Depart ment of Mines aeromagnetic maps published at a scale l inch = l mile (1:63,360). These maps are derived from data obtained at a mean flight altitude of 1,000 feet (305 m) above ground level along north-south flight lines of variable spacing ranging from /4 to ^ mile (400 to 1,200 m) but averaging about ^ mile (805 m). Surveys of this quality are generally not adequate for the detection of kimber lite pipes except in unusual circumstances where the flight path directly crosses a restricted, high amplitude magnetic source under thin non-magnetic cover. The ODM-GSC survey recorded a localized magnetic response of slightly more than 100 gammas on a single flight line which passed near the lamprophyre and kimber- litic intrusions at Coral Rapids (ODM-GSC Aeromagnetic Map 2306G: Coral Rapids). In 1972 Aquitaine Company of Canada Limited contracted a high sensitivity aeromagnetic survey over mining permits in the James Bay Lowlands covering an area of approximately 800 square miles (2,070 km2 ). The surveyed area is outlined on the Geological Map (back pocket) and is approximately bounded to the west by the Mattagami River and to the south and east by the Precambrian-Paleozoic contact. The survey consisted of 6,300 line miles (10,140 line kilometers) of flying on a square grid pattern with an average line spacing of J4 mile (400 m). A magneto meter capable of measuring the magnetic field in units of 0.02 gammas at half- second intervals was flown at a mean elevation of 600 feet (183 meters) ASL. A full description of operational procedures and discussion of the results are contained in a report filed with the Ontario Ministry of Natural Resources in Toronto (ODM Assessment Work Library, File No. 83.1-118). The Aquitaine aeromagnetic survey approaches the quality of work needed to detect targets of the scale and magnetic intensity of kimberlite intrusions and most certainly supersedes the l mile ODM-GSC aeromagnetic maps of the area. The Coital Rapids magnetic anomaly was recorded along both north-south and east-west flight lines and produced a maximum localized response of 600 to 700 gammas at the intersection of the two flight paths. A number of relatively small- sized, circular to elliptical localized anomalies of 50 to 150 gammas occur immediately east of the Little Abitibi River in an area extending up to 2 miles (3.2 km) east of the Bad River. The larger and more extensively continuous anomalies undoubtedly represent responses to magnetic geological features (such as north-trending diabase dikes) in the Precambrian basement modified by intervening Paleozoic cover and Quaternary overburden. Smaller highly localized anomalies might conceivably be explained by the subsurface presence of kimberlite pipes and diatremes penetrating Middle Devonian and older rocks of the Moose River Basin. Although the types of rocks underlying these anomalies are totally unknown, the existence of kimberlite at the bedrock-overburden interface in this area would adequately explain the distribution of pyrope garnets in the Little Abitibi drainage system. The idea would also be consistent with a concept of two-stage transport of indicator minerals involving dispersal in glacial till followed by Recent alluvial reworking. 33 Heavy Mineral Indicators of the Moose River Basin

GEOCHEMISTRY OF ESKER CLASTS AND HEAVY MINERALS IN DRIFT COVERED TERRAIN

A secondary objective of the James Bay Lowlands project was to obtain data on the metal potential and lithology of pre-Quaternary subcrop in extensive drift covered terrain by geochemical analysis of heavy mineral concentrates and statistical counts of pebble-sized rock clasts in esker gravel deposits. In particular, an attempt was made to assess the distribution of possible east-trending Archean metavolcanic belts under a cover of widespread glacial drift in the eastern part of the project-area and to determine the nature of the western extension of the Kesagami Lake metavolcanic belt outlined in a general way on the geological maps produced from Operation Kapuskasing (Bennett et d. 1967). Samples were collected along portions of 5 eskers, referred to as eskers A, B, C, D, and E on Chart A. In addition to the material collected for use in the search for kimberlite indicator minerals, a second bulk sample was obtained over a 4- foot (1.2 m) depth range of the C soil horizon in pits excavated in gravels situated along the esker nodes or crests. The samples were screened at the field sites, and a rough heavy mineral concentrate was obtained by panning the sieved material. The pan concentrate was again screened in the laboratory to isolate the — 30 4- 250 mesh fraction and the heavy mineral component of this fraction was separated in a tetrabromoethane liquid of specific gravity 2.96. Heavy mineral concentrates were pulverized, leached with hot HNOa-HCl (aqua regia), and analyzed for Cu, Zn, Pb, Ni, and Ag by atomic absorption spectroscopy. Molybdenum was determined colorimetrically. The results are shown in Table 7. At each esker site, a volume sample of approximately 200 rock clasts with minimum dimension in the size range of 8 to 16 mm was collected. These clasts were later identified, classified, and counted according to lithology. Data from these pebble counts were used to construct plots showing changes in the relative abundance of each major rock type along the esker axis (Figures 5, 6, 7, 8, and 9). Inspection of these charts indicates locations where point to point rising positive gradients or even constant slopes, give an indication that the esker gravels have received input of a particular rock type by subglacial erosion of an up-ice bedrock source. Relative down-ice increases in the abundance of any megascopically identifiable clast lithology are recognizable as positive slopes in Figures 5 to 9 and indicate that the esker has crossed subcropping bedrock of that lithology in the interval between sample sites. In extensive drift-covered districts, it has been possible to infer the existence of several minor, but previously unrecognized Archean- type metavolcanic-metasedimentary belts on the basis of down-ice increases in the abundances of mafic volcanic, felsic volcanic, chert, argillite and greywacke clasts in esker gravels. The outlines of inferred subsurface 'greenstone* belts shown on the Geological Map (back pocket) have been derived by correlating esker pebble count data (projected l mile (1.6 km) up-ice) with aeromagnetic anomalies shown on the ODM-GSC l inch to l mile aeromagnetic series maps. Selected volcanic rock clasts from esker sites (E195, E196, E200, and E221) located south of the Kesagami Lake 'greenstone' belt were analysed for SiCk, Total Fe as FeO, CaO, MgO, A12O3, K2O, Cu, Zn, Ni, and Ag. These data are listed in Appendix B. 34 TRACE ELEMENT CONCENTRATIONS HEAVY MINERALS (s.g. > 2.96) Table 7 FROM THE 30 TO 250 MESH FRACTION OF ESKER SEDIMENTS

Sample No. /Element Cu Pb Zn Ni Ag Mo Esker A E207 14 — 28 18 — — E211 28 25 35 25 2 — E214 8 — 28 15 — — E215 13 — 28 18 — — E220 14 — 34 19 — — E221 22 — 33 19 — — Esker B E174 16 — 43 27 4 — E175 28 26 42 66 2 — E177 18 — 35 18 5 — E181 10 — 30 17 3 — E182 15 — 26 15 3 — E192 10 25 33 24 — — E195 13 — 34 19 — — E196 10 — 30 16 — — E199 21 — 33 22 4 — E200 19 — 36 22 1 — E201 80 — 34 14 — 2 E203 8 — 26 14 3 — E204 8 50 26 12 4 — Esker C E131 39 — 44 36 6 2 E132 21 — 47 36 7 — E133 14 — 40 25 4 — E135 34 — 40 32 6 — Esker D E247 22 — 42 25 — — E250 36 — 51 27 — — E274 19 — 40 25 — — Esker E E223 30 30 43 36 — — E224 28 28 52 38 — 2 E225 28 30 42 30 — 2 E227 62 28 82 40 — 2 E228 60 26 74 45 6 — E229 20 30 48 26 — — E233 7 46 28 10 — — E238 54 26 56 54 — — E243 42 47 53 46 — — E244 32 25 48 27 — — E245 52 25 62 44 — — E246 42 — 75 34 — 2 Cu, Pb, Zn, Ni and Ag analyzed by atomic absorption spectroscopy. Mo analyzed colorimetrically by zyic dithiol method. — not detected. Lower detection limits: Pb — 25 ppm; Ag — l ppm; Mo — 2 ppm. 35 Heavy Mineral Indicators of the Moose River Basin

Table 8 TRACE ELEMENT ANALYSES OF MINERALIZED ESKER CLASTS

Esker Site- Clast No. Lithology-Mineralogy Cu Pb Zn Ni Ag Mo Esker A E211-1 Arkose; feldspar, quartz, mica, limonite 184 E211-2 Massive greenish grey dacite-rhyolite; pyrite 152 Esker B E195-1 Quartzite; disseminated pyrite 440 92 Esker D E250-1 Mafic volcanic porphyry; green feldspar 160 176 5 E250-2 Mafic volcanic porphyry; green feldspar 150 108 E250-4 xQuartz-chert; pyrite, pyrrhotite 590 80 190 - E274-1 Mafic volcanic; minor pyrite, pyrrhotite 260 175 49 - E274-2 Granitic; feldspar, quartz, pyrite, pyrrhotite 550 16 22 3 E274-6 Gabbro 139 47 Esker E E223-1 Serpentinite 8 1260 E238-5 Granitic; quartz, feldspar, mica, pyrite (5%), chalcopyrite 790 30 5 - - E238-6 Granitic; quartz (8(^), feldspar (1096), mica (596), pyrite, hematite 95 9 152 2 E238-7 Granitic; quartz, feldspar, mica, pyrite 58 50 37 2 E238-8 Granitic; quartz (7096), feldspar (1096), sericite (1096), sulphides (1096) 75 28 36 43 2 E243-4 Granitic; quartz, mica, pyrite 702 25 12 38 2 E244-3 Granitic; quartz, feldspar, sericite, pyrite 115 40 72 - E244-6 Arkose; disseminated pyrite 340 11 97 - E244-7 Chert; disseminated pyrite, pyrrhotite 136 182 62 - E244-9 Granitic; quartz, graphite, pyrite 330 11 18 - E245-1 Granitic; pyrite, molybdenite 104 4 E245-3 Granitic; feldspar, minor quartz, pyrite 34 20 73 3 E245-5 Granitic; red feldspar, quartz, sulphides 81 36 65 2 E245-6 Granitic; coarse grey feldspar, pyrite 151 39 66 - E245-7 Granitic; coarse feldspar, quartz, chlorite, pyrite 590 32 196 - E245-8 Coarse-grained quartz, pyrite layers 240 70 57 - E245-9 Granitic; quartz, feldspar, pyrite 26 18 61 2 E245-92 Granitic; coarse quartz, feldspar, pyrite 32 - 390 49 - E245-93 Granitic; feldspar, magnetite, pyrite 460 28 48 4 Note: Cu, Pb, Zn, Ni and Ag analysed by atomic absorption spectroscopy. Mo analysed colorimetrically by zinc dithiol method. — not detected. Lower detection limits: Pb—25 ppm; Ag—2 ppm; Mo—2 ppm. 36 At several of the esker sites, rock clasts containing disseminated sulphide mineralization were collected in the course of systematic searches in and near the excavated pits. Sulphide-bearing clasts were individually pulverized to —200 mesh size, and analysed for one or more of the elements Cu, Pb, Zn, Ni, Ag, and Mo. The trace element data for clasts containing unusually high concentrations of any of these metals are listed in Table 8.

Esker A

Esker A has been traced southward intermittently over a length of 30 miles (48 km) along the Wakwayowkastic and Little Wakwayowkastic Rivers, beginning at a point about 2 miles (3 km) west of Nettogami Lake. The esker morphology is generally good, but glacial overriding by the readvancing Cochrane ice sheet has left a veneer of Kipling-Cochrane Till covering the esker gravels. Samples were collected from the esker beads where overlying till was absent or less than 4 feet (1.2 m) thick. Such areas of thinner till cover were generally found to be on the west side of the esker bead just below the crest — presumably the lee side of the south to southeast-trending esker ridges. The distribution of tree species was also useful in outlining areas of thinner till cover; jack pine and red pine species are normally more abundant in areas of well-drained soil developed on sandy and gravelly esker deposits. Balsam, black spruce and aspen species occur mainly in areas of less well-drained soil over continuous, thick, clay-rich deposits of till and/or lacustrine sediments. The thickness of the Kipling-Cochrane Till cover at each sample site varied as follows: E207 — O to 6 + feet (O to 1.8 + m); E211 — O to 2 feet (O to 0.6 m); E215 — O to 3 feet (O to l m). At localities E214 and E220 no overlying cover was present. Massive esker gravels or alternating beds of gravel and stratified sand were excavated and sampled at each site. Elsewhere along the length of the esker, gaps in the sampling are caused by failure to penetrate till thicknesses greater than 5 feet (l .5 m). Between-site variations in the relative abundances of types of 8 mm to 16 mm sized rock clasts in Esker A are shown in Figure 5. At locality E211, positive gradients are shown for granitic, felsic volcanic and greywacke-arkose rock types. Argil!ite-siltstone clasts show an increase between site E207 and site E215 while Paleozoic carbonate rocks remain at a constant high level over this interval of the esker. Elevated levels of felsic volcanic clasts are present at locality E220. Mafic volcanic rocks, argillite-siltstone, and sandstone are more abundant at site E221 relative to site E220. The abundance of clasts of Paleozoic carbonate rocks decreases southward from about 30 per cent at the northernmost sample site (E207) to about 15 percent at the southern terminus of the esker (E221). Clasts identified megascopically as volcanic rocks at locality E221 were chemically analysed and the results are given in Appendix B. Volcanic compositions cover a wide range from basalt to rhyolite but a substantial proportion of the clasts are dacitic; some dacites contain above normal amounts of K^O associated with sericite alteration. Two mineralized clasts collected at locality E211 contained anomalous copper concentrations (Table 8). Trace element levels in tetrabromoethane heavy mineral separates from the — 30 H-250 mesh fraction of the esker sediments are generally low and relatively 37 Heavy Mineral Indicators of the Moose River Basin

VOLCANIC MAFIC

OC DC co o

S 8 S S 2-

ocz

Ci ^

V " -SIZ 5 S .2 .2

"T—T T—i—i—r in o "o o O O o ft o o o o o o 5f P) CN —

VOLCANIC — /rt 111 FELSIC 85 li

38 i sg || S f | IE < O x Z) < ne ac a S > o o is o <

S 3 88 S 2S.nc S n o 2 S m e}

-Ul

m l X e

"Si S

a t

ampleSites

-001

f \ \ 1 , i \\ \/ •Ml i 'ic .2

•Ml •W , ^ •Ml \ 1 1 \ S yi f r s l •III *J -181 f n

•Ul j l 1 1 •Ml o m o 2 g o g w LI} 3 i St ? 8 8 2 e

Uj H y 5 x u " —So i -j *x <" —IK tn 5jin 2 o UJO O-U O l~ J/i ffi |I 5s g2 Heavy Mineral Indicators of the Moose River Basin constant. Microscopic examination of the heavy mineral concentrates showed no evidence of sulphide minerals and it was concluded that metal sulphides are normally not present in near-surface deposits of permeable, well-drained esker gravel, implying that sulphide cations have been redistributed by secondary weathering processes involving chemical and physical leaching by ground-waters. For the most part, the trace element analyses of heavy minerals given in Table 7 probably reflect nothing more than the metal concentrations of stable oxide minerals, primary silicate minerals and secondary iron and manganese oxides. With few exceptions, the redistribution of metals (eg. Zn, Cu, Ni) by near-surface weathering processes has produced relatively narrow limits of metal variation in the heavy mineral fraction of — 30 4- 250 mesh material.

Esker B

Esker B can be traced south-southeastward over a 30 mile (48 km) length in the low-lying land between Yesterday Creek and Stringer Creek. Esker morpho logy is good and the overlying Kipling-Cochrane Till is absent or discontinuous in the northern segment. Farther south, between localities E196 and E199, attempts to penetrate the till cover by hand-pitting were not successful. At sample sites E174, E182 and E200 there is no till cover over the esker material. At other sites along esker B deposits of Kipling-Cochrane Till and/or lacustrine clay vary in thickness from one foot (0.3 m) to 5 feet (1.5 m). Site-to-site variations in the relative abundances of different types of rock clasts in esker B are shown in Figure 6. The same overall southward decrease in the abundance of Paleozoic carbonate clasts that was noted in esker A is also a feature of esker B. The proportion of granitic clasts increases markedly between localities E182 and E192 and the percentage of carbonate rocks decreases significantly in this interval. Positive gradients for felsic volcanic rocks, chert and argillite-siltstone between sites E192 and E195 indicate that the esker has received input from these types of bedrock sources within this interval. At locality E196, high levels of felsic volcanic clasts persist and increased levels of mafic volcanic components are noted. Positive gradients for felsic volcanic and mafic volcanic rocks also occur between site E199 and site E200 indicating increased input of these components into the esker from subsurface bedrock sources. Rock clasts identified as felsic to mafic metavolcanic at localities E195, E196 and E200 were chemically analysed. These data are given in Appendix B. Several of these clasts contained anomalously high concentrations of copper and two clasts from locality E195 show unusually high nickel values (800 ppm and 1080 ppm). A pyrite-bearing quartzite clast from locality E195 contained 440 ppm copper (TableS). Trace element analyses of the tetrabromoethane heavy mineral concentrates (Table 7) indicate that heavy minerals in esker B (and also esker C) contain unusually high levels of silver. In addition, anomalously high concentrations of copper (80 ppm) and Mo (2 ppm) are present in the heavy mineral fraction recovered from sample E201. Heavy mineral sample E204 contains above normal amounts of lead (50 ppm) and silver (4 ppm). 40 Esker C

Esker C lies west of eskers A and B and is parallel to, and about 2 to 3 miles (3 to 5 km) east of the Upper Little Abitibi River. The esker morphology is good, but thick deposits of Kipling-Cochrane Till cover the central and southern segments, and only the northernmost segment could be sampled. Massive and stratified esker gravels were sampled at localities E131 and E132 where there was no till cover; at locality E133 where there was l to 3 feet (0.3 to l m) of overlying till; and at locality El35 where there was 1^ feet (0.5 m) of clay-gravel cover. The percentage distribution of rock clast types in esker C is shown in Figure 7. Positive gradients for felsic volcanic, quartzite, greywacke, and mafic volcanic clasts indicate that the esker has probably crossed a narrow metavolcanic-metasedimentary belt between localities E131 and El33. Elevated levels of granitic clasts are present at sites E132 and E133. A large increase in the proportion of Paleozoic carbonate clasts (from 3 to 30 percent) between sites E133 and E135 leads to a decrease or negative slope for most of the other components. No mineralized clasts were discovered in esker C. Trace element analyses of heavy mineral separates from esker C (Table 7) show consistently high silver levels of 4 to 7 ppm. Copper, lead, zinc and nickel are present in the heavy minerals in normal background concentrations.

Esker D

Esker D trends south-southwesterly through Gurney Township 6 to 10 miles (10 to 16 km) west of the Groundhog River. Its morphology is poor and it is masked by a nearly continuous cover of Barlow-Ojibway clay sediments and in some cases by Cochrane Till. Gravel pits have been opened at 3 places in the esker. At locality E247, esker gravels are exposed at surface, at E250 the esker is covered by 5 feet (1.5 m) of clay and mixed clay and cobbles, and at E274, about 10 feet (3 m) of cover has been stripped to expose the esker gravel and sand. The distribution of rock clast types at each locality within esker D is shown in Figure 8. About 25 to 30 percent of the clasts at all 3 sites are Paleozoic rocks derived from bedrock mainly in the Hudson Bay-James Bay Lowland. A significant increase in the abundance of mafic and felsic volcanic clasts occurs between localities E247 and E250. Several mineralized clasts collected at localities E250 and E274 contained copper in amounts ranging from 139 ppm to 590 ppm (Table 8). The heavy mineral concentrates at all 3 sites contain normal background levels of Cu, Pb, Zn, Ni, Ag and Mo.

Esker E

Esker E extends southward through Boyle, Guilfoyle, Pearce and Teetzel Townships over a length of about 28 miles (45 km). It crosses the railway line connecting Kapuskasing with Smokey Falls, and numerous gravel pits have been 41 Heavy Mineral Indicators of the Moose River Basin

Esker Transport Direction

* h4 -70 -60 -50 GRANITIC -40 -30 FELSIC 10- VOLCANIC 5- r^^- 0-

-10^ MAFIC ^^. VOLCANIC -0 "c AMPHIBOLITE, 20- 0) MICA SCHIST 30- o OJ 0- \^^ a

c: -10 CHERT (*) o -5 QUARTZITEH 0) Ks— t -0 ARGILLITE 4 SILTSTONE 5- ^ SANDSTONE t- A^ " GREYWACKE a Q ARKOSE (t)

FOSSILIFEROUS 40- 30- ROCKS{*) 20- CARBONATES (*) 10- 0- ———*sJ*--^.r-n— i ———— —————— r fc ——— J2PJJ2— (M" oIO O2 . Sample Sites 0 5 10 ^^^^L ' ' . r y i Miles Kilometers SMC 12990 Figure 7-Variations in the relative abundances of 8 mm-16 mm sized rock clasts in Esker C. 42 LU UJ ^ -^ Q ~ t n o ~ z i N R ^ uj w 5 co Q > O y "l Z UJ * 8 23 ^ DC CC > iuaojad o O CO CD <

in ____ II II i i i III II 1 1 1 u ; * -0 1 i \ \ 1 1 1 li i t -/l

l' k o ffi Q J ' OJ Transport w -w 1 J j 1 y i ^J J 1 i \ Q. a to (D JC CO UJ .--

o aj eaO) 2 0) 'c (D ^ IS l --*, co 'C

z 1 II II li 1 1 1 1 ino ooof— ooocN 1— o"oo— ooooc-q m e* -~ j luaojad -y o P t ea w i^ t! o z li 5 ujuj O^H t S2 *t Oo "- z cco^ UJ 3g |8 'j 0 uj gz c^ S5 lo o J2 3^2 go Heavy Mineral Indicators of the Moose River Basin

g 28 w 50 Q >% Z Ultt < 0^ CO O

44 exposed along industry roads that traverse parts of the esker. The morphology of esker E is good, and the overlying clay and/or till cover is discontinuous. At sample sites E224, E225 and E238 there is no clay cover over the esker material. At other sites the thickness of the overlying Cochrane Till or Barlow-Ojibway Formation varies from 2 feet (0.6 m) to 15 feet (4.6 m) at E246. The between-site variations in the relative abundances of types of 8 mm to 16 mm sized rock clasts in esker E are shown in Figure 9. At the northern end of the esker, Paleozoic carbonate rocks comprise about 30 percent of the clasts collected from pits in the esker material at localities E223 and E224. Between sites E224 and E225, the percentage of carbonate and fossiliferous rocks decreases markedly and increased levels of felsic and mafic metavolcanic clasts were recorded at E225. At localities E228, E243, and E244, carbonate clasts show positive gradients which may indicate the existence of Paleozoic outliers in up-ice areas sampled by the esker. Trace element concentrations in the tetrabromoethane heavy mineral separates are given in Table 7. The elements Cu, Pb, Zn and Ni vary from sample to sample only within narrow limits — generally about a 2-fold variance is normal. Overall however, all four of these elements appear to be present in the heavy minerals of esker E in slightly higher average concentrations than in the heavy minerals of eskers A, B, C and D. In particular, the lead and to some extent the molybdenum contents appear to be higher. These subtle differences in the trace element chemistry of heavy mineral may indicate that esker E has sampled a chemically distinctive bedrock source not present in the areas traversed by the other four eskers. A large number of mineralized clasts were collected from localities along esker E. Inspection of the data summarized in Table 8 shows that a relatively large proportion of these mineralized clasts are quartz-feldspar-mica (sericite-chlorite) rocks with disseminated pyrite, pyrrhotite and minor chalcopyrite or molybdenite. Many of these granitic clasts contain anomalously high concentrations of copper (104 ppm to 790 ppm) and molybdenum (2 ppm to 4 ppm). The occurrence of these mineralized granitic clasts is confined to the southern half of the esker, and it seems possible that the esker may have crossed a large subsurface source of disseminated pyrite, chalcopyrite and molybdenite in granitic rocks situated south of sample locality E228.

THE PALEOZOIC-PRECAMBRIAN BOUNDARY

The location of the main Paleozoic-Precambrian boundary outlined on the Geological Map differs somewhat from that shown on earlier l inch to 2 mile (1:126, 720) geological outcrop maps of the Ontario Department of Mines (Bennett et ed. t 1966a-f, 1967 a-b). In general, our work indicates that the main contact between Precambrian and overlying Paleozoic rocks should be moved southward at some locations, and that a significant adjustment in its position should be made in the area immediately east of the Abitibi River in Hobson, Ophir, Valentine, Heath, Pitt, and Wacousta Townships. In the course of sampling alluvium in the major river valleys during a mid summer low water-level period, it was possible to examine blocks, boulders and smaller rock particles in the river channels at and near bedrock, and to record the approximate ratio of Paleozoic to Precambrian rock pieces. The results are plotted 45 Heavy Mineral Indicators of the Moose River Basin

on the Geological Map. These data along with outcrop observations along the river valleys, were extrapolated between the river systems with the aid of ODM-GSC l inch to l mile (1:63,360) aeromagnetic maps which generally show a damped, low noise magnetic response in areas where Precambrian rocks are masked by overlying Paleozoic sediments. The boundary outlined on Chart B indicates that the segment of the Paleozoic-Precambrian contact extending from the Little Abitibi northeast ward to Southbluff Creek is mainly controlled by a topographic uplift in the Precambrian basement coincident with major northeast faulting along the northwest flank of the Kapuskasing granulite zone.

46 Aooendix A WEIGHTS OF HEAVY MINERAL FRACTIONS (S.G^+3.1) AND KK SUMMARY MINERALOGY

Weight in Grams * Observations Sample As After Heavy Heavy Note: Screening Fraction Screened n = refractive index; > = greater than; No. Received < = less than

1 113.31 110.28 3.2 2.8 Pale mauve pink, mauve with inclusions, orange-red garnets - n > 1.76 LT2 189.38 185.01 9.52 5.1 Garnets - pale pink, orange-red, pink- purple - n > 1.76 3 33.43 32.43 1.70 5.2 Garnets - pale pink, deep reddish, very pale pink - n > 1.76-1 grain apatite 4 146.45 142.34 11.31 7.9 Pale pink, very pale pink garnets n > 1.76 -sphene 5 180.41 177.48 7.42 4.2 Considerable mafics, little sulficles or garnet - pink garnet - n > 1.76 - epidote, staurolite, limonite 11 140.24 137.84 9.48 6.9 Plum (blue-coloured) garnet - n > 1.76 12 99.40 93.40 9.98 10.7 Blue, orange, deep red garnets - n > 1.76 LT13 80.65 71.27 2.66 3.7 Blue garnets - n > 1.76 - pyrite LT14 55.81 52.40 1.79 3.4 Blue, pink garnets - n > 1.76 - milky white axinite ATI 5 90.38 87.31 2.45 2.8 Coated garnet - n > 1.78 - fresh pyrite AT16 62.40 61.23 1.31 2.1 Pale pink garnet - n > 1.76 17 39.74 35.63 1.29 3.6 Pink St orange garnet 18 135.20 133.12 5.88 4.4 Few garnets - pink St red AT19 105.40 103.12 3.78 3.7 Purple-pink garnet - n > 1.76 - some sulfides 20 181.20 177.47 26.05 14.7 Usual garnet - considerable pyrite 21 118.02 116.20 11.36 9.7 Pale pink garnet - n > 1.76 22 194.22 189.62 38.41 20.2 1 angular pyrope 1.74 < n < 1.75 1 rose-purple rounded pyrope n ~ 1.74 23 103.01 101.08 6.73 6.7 Pink euhedral, blue-pink garnets 24 104.66 102.81 13.52 13.2 Much pink garnet AT26 113.80 111.74 1.21 1.1 Sulphides 27 185.18 182.16 18.25 10.0 Very pale pink garnet - n > 1.76 28 125.88 121.62 17.94 14.8 1 purplish rounded pyrope - 1.74 < n < 1.75 33 82.08 79.32 5.84 7.4 Many white to light green hexagonal barite crystals - 6 mauve garnets - n > 1.76 - garnet abundant - 1 reddish, rounded pyrope - n csi 1.74 34 180.64 177.30 22.79 11.3 Many garnets - 2 barite crystals 35 137.96 134.78 16.06 11.9 No comments 36 106.00 105.39 18.78 17.8 Pale pink garnet - n > 1.76 47 Heavy Mineral Indicators of the Moose River Basin

Weight in Grams Sample As After Heavy Heavy No. Received Screening Fraction Screened Observations

76 103.89 102.92 1.06 1.0 No garnets LT77 64.46 63.26 1.60 2.5 Pale pink garnet 1.80, very pale pinkish grey garnet 1.79, pale orange garnet - 1.79 < n < 1.80 78 161.36 158.66 19.22 12.1 l pale pink, l orange-red garnet - n ~ 1.80 pale green diopside - l rounded purple, l rounded dark red pyrope- n csj 1.74 79 98.00 97.30 7.70 7.9 Sulfides - fine-grained pyrite including fossils, l rounded rose-pink pyrope - n < 1.74 80 115.11 112.41 8.51 7.6 Euhedral ilmenite, chromite, l grain chalcopyrite, fine grained sulfides - red garnet — 3096 hornblende, rounded limonite - no round silicates LT81 75.77 73.17 2.60 3.6 Orange-red garnet - n > 1.76 82 127.25 125.00 9.25 7.4 l grain aquamarine apatite 83 108.12 107.24 19.39 18.0 No comments 84 87.04 86.00 12.45 14.5 Few garnets — 2096 - all grains have weathered coating - hornblende and mafic minerals dominant some euhedral garnets - l or 2 rounded AT85 23.02 21.32 3.60 16.9 Orange garnet - n — 1.77, orange-red garnet-n > 1.78 86 133.03 131.93 43.04 32.7 Reddish orange garnet- n = 1.80, pale pink, very pale pink garnets - n > 1.80 - sulfides, l well rounded, deep purple pyrope n — 1.74 87 165.86 164.26 33.13 20.2 Pale pink, very pale pink garnets - n > 1.78, orange-red garnet - n > 1.80 - number of garnets close to Kirkland Lake garnets* in colour but n > 1.76 88 141.84 139.64 44.44 31.8 l flattened, rounded, pinkish purple pyrope - n — 1.74 89 473.87 466.76 210.31 45.2 Red and pink garnets, rounded and euhedral - n > 1.76 much brown garnet -n^l.77 90 114.64 116.12 22.98 19-8 l apatite grain 91 180.94 179.05 44.93 25.0 Garnets less abundant — 3096 - l rounded pinkish garnet - n > 1.76 92 253.82 250.95 74.03 28.6 One purplish pink garnet - n > 1.76 93 88.56 87.42 21.58 24.7 30-40# red and brown angular garnet - subangular and pitted mafics, epidote - rounded limonite l grain pale yellow apatite 94 188.84 186.24 76.54 41.2 l well rounded purplish pyrope - apatite *Lee,H.A., (1965). 48 Weight in Grams Sample As After Heavy Heavy No. Received Screening Fraction Screened Observations

37 160.28 157.10 22.02 14.0 Minor sulfides - blue - black hematite and apatite 38 128.62 126.02 27.50 21.8 Few sulfides - considerable brown garnet - n > 1.78, much hornblende - pink garnet - n > 1.76 - some grains have whitish coating 39 140.10 137.20 12.52 9.1 8096 garnets - many orange and brown - 8 rounded epidote, hornblende, barite - some grains have whitish coating 40 149.90 148.41 40.72 27.4 5096 garnets 41 131.11 129.56 17.31 13.4 No comments 42 89-90 86.70 17.42 20.4 l aquamarine apatite 43 153.98 151.80 29.98 19.8 Many weathered limonite grains - several clear quartz grains - rounded quartz with pyrite crystals 44 322.89 311.21 156.60 50.0 Deep purple, well rounded pyrope with inclusions - n c* 1.75 - l rounded purple pyrope, l rose-purple rounded pyrope -1.74 < n < 1.75 -1 rounded pale purple, l rounded medium purple pyrope - n ^ 1.74 some sulfides 46 309.34 306.32 50.90 16.6 Few sulfides - garnets all > 1.76 47 181.51 179.95 25.69 14.3 Few quartz grains AT48 37.80 36.32 1.40 3.9 l blue garnet - 1.78 < n < 1.79 49 83.19 81.78 15.41 18.8 1 grain sulfide - euhedral sphene - sphalerite tetrahedron 50 60.78 59.75 14.70 24.6 Pink garnets - few sulfides 54 95.25 94.30 40.89 43.4 Few garnets - < 1096 55 96.69 93.39 23.18 24.8 2 aquamarine apatite grains 57 50.53 47.33 1.59 3.4 No comments 65 101.20 99.85 25.40 25.5 5096 garnet LT66 70.64 69.17 5.11 7.4 Pyritized fossils - abundant sulfides 67 104.22 102.69 3.49 3.4 2096 garnets 68 119.62 118.06 16.94 14.4 2596 garnet - many brown - much horn blende - few rounded limonite and hematite - 2 rounded garnets 69 153.46 151.85 13.98 9.2 Few garnets - pale blue apatite grain 70 171.10 168.79 38.20 22.6 l well rounded, deep purple pyrope - 2596 garnet - many brown - angular pyroxene and amphibole - rounded limonite 71 115.40 114.31 9.69 8.5 Very few garnets - < 2096 73 122.22 120.45 19.04 15.8 5096 garnet - look "fresh", all angular - hornblende, epidote 49 Heavy Mineral Indicators of the Moose River Basin

Weight in Grams Sample As After Heavy Heavy No. Received Screening Fraction Screened Observations

95 175.06 173.61 58.57 33.8 Garnet with phlogopite inclusions - n > 1.76 - blue and green apatite 96 186.91 184.27 67.85 36.9 Approx. 7016 garnets - several grains green and aquamarine apatite 100 138.53 136.72 25.49 18.7 l pinkish purple garnet - n > 1.76 101 171.80 170.56 50.14 29.4 Several grains green and blue apatite 102 236.31 234.68 73.43 31.2 Dozen blue and green apatite grains - 3 red-purple garnets - n > 1.76 103 112.83 111.41 34.30 31.0 Unusually large amount apatite - green and blue, rounded and euhedral KT104 23.78 23.41 0.56 2.4 l grain apatite 105 88.48 87.76 25.63 29.2 Dark sample - mafic minerals, iridescent pyroxene, hexagonal apatite, banded limonite, garnet attached to quartz 115 120.92 119.30 20.73 17.3 No comments 116 195.18 192.54 53.68 27.9 l reddish, l pinkish garnet - n > 1.76 117 260.67 255.72 92.45 36.3 Accretion of pyrite around quartz grain, oxidized exterior - banded limonite grain - pyrite crystals, reddish oxidation - rounded hematite 118 91.44 89.05 7.44 8.3 Brown garnet - n > 1.76 - contains birefringent material 119 34.07 33.63 0.89 2.6 Blue apatite - l pale purple, l reddish purple - n > 1.76 120 62.00 61.25 6.40 10.5 Few garnets, some apatite 121 61.01 59.75 5.84 9-8 Considerable light brown garnet - n ^ 1.77 122 71.54 69.71 3.76 5.5 Very little garnet, considerable hornblende 125 17.57 16.68 0.75 4.5 Mostly hornblende, few brown and pink garnets 126 34.25 33.78 0.81 2.4 Only l or 2 garnets E131 133.56 131.79 27.88 21.2 Many brown garnets - approx. 60* garnet few grains apatite - blue, brown, reddish, dull red and light mauve garnets - n > 1.76 E132 173.35 170.32 31.48 18.5 Many brown garnets - pink, light purple, light mauve, weathered purple garnets - n > 1.76 E133 86.70 84.11 17.69 21.0 Pink and brown garnet - n > 1.76 E135 140.60 138.43 12.05 8.7 Pink and brown garnets - n > 1.76 152 115.08 112.68 24.83 22.1 Very pale pink garnet - n > 1.76 - diopside 50 Weight in Grams Sample As After Heavy Heavy No. Received Screening Fraction Screened Observations

KT170 85.52 84.48 6.18 7.3 Bright blue apatite - hornblende with round green inclusions - purplish garnets - n > 1.76 E171 115.31 113.38 7.28 6.4 Bright blue apatite, epidote - < 1096 garnets E174 146.08 143.38 10.34 7.2 Dark reddish purple, rounded purple, mauve with inclusions garnets - n > 1.76 - all grains angular with whitish coating - hornblende, epidote E175 55.49 54.39 11.69 21.5 Many brown garnets - approx. 70* - 2 like Kirkland Lake garnets* in colour but a>l.76 E177 90.19 89.15 4.92 5.5 Brown and pink garnet - n > 1.76 - brown limonite replacing pyrite E181 60.55 58.52 1.33 2.27 Pale grey-pink, pale brown garnets - n > 1.76 pale brown hypersthene - l round garnet - 3096 garnets - all grains have whitish coating - epidote, horn blende, mafic minerals E182 47.82 46.64 0.87 1.9 Some quartz - purplish garnet - n > 1.76 KT185 75.38 74.38 1.73 2.0 Many brown garnets KT186 22.21 21.89 0.49 2.2 Half dozen garnets E192 56.40 55.42 1.20 2.2 No comments KT193 47.69 46.90 0.26 .0.5 No comments E195 131.55 130.09 8.48 6.5 2 purplish garnets - n > 1.76 E196 116.20 113.05 9.00 8.0 Some epidote - considerable garnet - l round - hornblende, minor limonite - all particles angular E199 99.49 97.59 10.33 10.6 l rounded purple-red pyrope - l rounded purplish pyrope - 1.74 < n < 1.75 E200 67.15 66.63 2.13 3.2 No comments E203 52.12 51.50 1.81 3.5 White epidote - n ^ 1.73 - pale green apatite, pale pink garnet - n > 1.76 - clear quartz grain E204 57.68 56.76 2.88 5.1 Few garnets E207 64.58 64.17 1.62 2.5 No comments KT209 67.05 66.10 3.25 4.9 Hypersthene E211 139.29 137.70 11.79 8.6 Subhedral brownish grey garnet - n > 1.76 l dark brown grain n ^* 1.76 E214 66.68 65.63 1.14 1.7 No comments E215 22.81 22.33 0.69 3.1 Epidote, sphene, few garnets KT218 69.08 64.10 4.55 7.1 3 reddish-purple garnets - n > 1.76 E220 187.25 186.00 17.85 9.6 Abundant red and pink garnet - large sphene crystals - pale blue apatite - l reddish, l pinker than Kirkland Lake garnets* - 1.76 *Lee,H.A., (1965). 51 Heavy Mineral Indicators of the Moose River Basin

Weight in Grams •X* Sample As After Heavy Heavy No. Received Screening Fraction Screened Observations

E221 78.10 77.23 3.69 4.8 Pale blue apatite, few garnets, some epidote KT222 41.11 40.24 3.34 8.3 1 pinker than Kirkland Lake garnets* - n > 1.76 E223 56.37 54.73 6.72 12.3 No comments E224 43.58 43.05 4.13 9.6 No comments E225 35.62 34.30 2.30 6.7 No comments E227 70.20 64.44 8.50 13.2 1 grain apatite - 2 reddish garnets -n > 1.76 E228 60.26 58.40 3.19 5.5 1 grain apatite E233 64.00 62.55 8.44 13.5 Many garnets - some have whitish coating E238 47.12 46.61 5.70 12.2 No comments E243 41.73 41.20 3.56 8.6 No comments E244 29.80 29.49 1.12 3.8 Some epidote E245 50.49 46.39 2.32 5.0 No comments E246 43.92 43.46 1.30 3.0 1 rounded red-brown garnet - n > 1.76 E247 58.02 50.48 6.91 13.7 1 rounded light pink garnet - n > 1.76 E250 93.45 91.15 19.59 21.5 Blue apatite 259 56.71 55.37 11.83 21.4 Blue apatite, relatively few garnets - 1 reddish garnet - n > 1.76 260 207.40 205.02 60.69 29.6 Blue apatite - many brown garnets 261 51.68 51.20 3.81 7.5 20* garnets - 1 pink, 1 light purple garnet - n > 1.76 262 69.98 69.58 17.51 25.2 Green apatite - rounded red, dull pink, rose-pink, 2 purplish pink, euhedral pink garnets - n > 1.76 263 40.71 40.43 5.04 12.5 Few garnets - green apatite 264 70.65 69-90 29.15 41.7 Blue apatite, pyroxene crystal - large reddish, pink, rounded reddish, red- brown rounded, pink rounded garnets - n > 1.76 265 113.37 111.83 60.42 53.9 Many brown garnets - 2 reddish, 2 pinker than Kirkland Lake garnets* - n > 1.76 266 126.58 124.04 63.28 51.0 Blue apatite grains - 1 rounded red, 1 like Kirkland Lake garnets* - n > 1.76-1 rosy (bluish red) pyrope - 1.74 < n < 1.75 - 1 pink pyrope - n s* 1.75 268 34.20 32.89 1.18 3.6 Very few garnets 269 95.00 93.58 18.38 19.7 Many garnets - red and brown - 1 pinker than Kirkland Lake garnets* - n > 1.76 E272 79.24 77.19 1.95 2.5 Epidote, apatite, some staurolite, 1 purple, 1 pink (resembles pyrochlore) zircon, considerable pink garnet E274 140.95 117.70 5.31 4.4 Considerable garnet, enstatite *Lee,H.A., (1965). 52 Appendix B PARTIAL CHEMICAL ANALYSES OF VOLCANIC ROCK CLASTS FROM ESKER SITES E195, E196, E200, E221

Partial Chemical Analyses of Volcanic Rock Oasts from Locality E195

PERCENT PPM

SiOz A120, K2O CaO FeO MgO Cu Zn Ni

High alumina basalt 49.1 16.0 0.36 14.4 9.63 4.73 192 35 800 Andesite 51.1 12.2 0.88 10.4 6.93 10.6 5 24 75 Basalt 50.2 13.9 0.28 8.24 13.50 4.80 176 66 93 High alumina basalt 47.4 16.4 1.77 8.08 9.90 6.84 16 71 73 High alumina basalt 51.8 19.4 1.58 7.92 8.64 4.27 280 42 38 Dacite 61.5 17.0 1.24 6.76 4.77 1.36 5 20 17 Rhyolite 68.4 14.0 2.69 2.52 5.04 2.15 16 55 47 Cherty Rhyolite 68.6 3.48 0.32 6.38 2.88 6.88 112 28 1080 Cherty Rhyolite 70.0 9.35 0.10 7.60 7.65 1.59 41 38 39 Rhyolite 68.4 14.0 2.69 2.52 5.04 2.15 16 55 47

Analyses by the Mineral Research Branch, Ontario Division of Mines, 1973. K2O analysed by flame emission spectroscopy. All other oxides and trace elements analysed by atomic absorption spectroscopy.

Partial Chemical Analyses of Volcanic Rock Clastsfrom Locality E196

PERCENT PPM

SiO2 AljO, K,0 CaO FeO MgO Cu Zn Ni

High iron, high alumina basalt 44.3 17.5 0.24 6.53 14.49 7.53 45 74 136 Calcareous basalt 45.1 15.5 0.10 18.6 10.17 5.49 16 8 22 Basalt 50.0 15.0 0.72 9.68 11.97 6.27 20 62 33 Basalt 47.3 15.7 1.04 8.67 11.34 6.92 38 39 75 High alumina andesite 49.6 21.5 0.16 12.7 8.10 1.27 5 20 9 Basalt 50.9 13.4 0.08 8.27 14.13 5.45 194 46 24 Basalt 51.1 12.1 0.64 7.65 12.60 6.42 118 54 45 Dacite 60.9 15.7 2.53 3.19 5.67 5.14 5 32 62 High alumina andesite 57.7 20.0 1.14 6.98 5.67 2.19 22 38 16 High alumina andesite 58.3 18.3 1.12 6.60 6.39 2.60 12 49 12

Analyses by the Mineral Research Branch, Ontario Division of Mines, 1973. KiO analysed by flame emission spectroscopy. All other oxides and trace elements by atomic absorption spectroscopy. 53 Heavy Mineral Indicators of the Moose River Basin

Partial Chemical Analysts of Volcanic Rock Clast* from Locality E200

PERCENT PPM

SiO, Al,0, K,0 CaO FeO MgO Cu Zn Ni

Basalt 52.4 13.4 0.16 5.76 12.33 5.00 94 87 29 Basalt 46.4 13.7 0.10 11.3 10.71 6.40 87 77 117 Andesite 55.0 16.6 0.32 6.50 8.55 4.00 164 36 149 Andesite 50.9 14.1 0.32 9.22 9.18 4.80 64 89 124 Basalt 47.9 15.2 0.10 10.3 11.07 7.20 112 52 85 Basalt 53.4 17.3 0.16 3.25 12.33 5.10 110 147 114 Andesite 57.4 13.1 0.93 7.20 9.81 5.00 44 56 24 Andesite 51.9 14.8 0.24 13.1 6.66 5.20 26 30 17 Basalt 48.1 8.81 0.10 9.92 9.09 6.80 6 40 340 Basalt 49.1 14.3 0.16 9.14 11.07 8.20 32 56 81

Analyses by the Mineral Research Branch, Ontario Division of Mines, 1973. KjO analysed by flame emission spectroscopy. All other oxides and trace elements by atomic absorption spectroscopy.

Partial Chemical Analyses of Volcanic Rock Clans front Locality E221

PERCENT PPM

SiOz MO. KzO CaO FeO MgO Cu Zn Ni

Basalt 49.8 14.9 0.24 9.14 11.61 6.95 43 132 69 Basalt 50.7 14.6 0.24 9.15 13.50 5.40 114 75 49 Cherty dacite 63.0 13.3 0.10 12.1 6.48 1.20 14 20 9 High potash andesite 58.4 16.7 3.13 3.14 5.40 4.10 10 50 66 Dacite 62.7 15.9 2.41 3.53 5.40 2.75 40 76 63 Dacite 62.5 13.9 2.33 4.24 6.48 3.00 48 53 43 High potash dacite 61.3 17.8 4.01 0.99 6.39 3.70 8 136 62 Rhyolite 70.0 15.9 2.33 2.98 2.48 1.20 18 42 10

Analyses by the Mineral Research Branch, Ontario Division of Mines, 1973. KiO analysed by flame emission spectroscopy. All other oxides and trace elements by atomic absorption spectroscopy. 54 REFERENCES

Bell, J. M. 1904: Economic resources of Moose River basin; Ont. Bur. Mines, v. 13, pt. I, 1904, p.135-179. Bell, R. 1877: Report on an exploration in 1875 between James Bay and Lakes Superior and Huron; Geol. Surv. Can., Rept. Prog., 1875-1876, p.294-342. Bennett, G., Brown, D. D., and George, P. T. 1966a: Otter Rapids Sheet, District of Cochrane; Ontario Dept. Mines, Prelim. Geol. Map. P.370, scale l inch to 2 miles, Geology 1966. 1966b: Kesagami Lake Sheet, District of Cochrane; Ontario Dept. Mines, Prelim. Geol. Map. P.371, scale l inch to 2 miles, Geology 1966. 1966c: Cochrane Sheet, District of Cochrane; Ontario Dept. Mines, Prelim. Geol. Map. P.372, scale l inch to 2 miles, Geology 1966. 1966d: Burntbush River Sheet, District of Cochrane; Ontario Dept. Mines, Prelim. Geol. Map. P.373, scale l inch to 2 miles, Geology 1966. 1966e: Onakawana Sheet, District of Cochrane; Ontario Dept. Mines, Prelim. Geol. Map. P.375, scale l inch to 2 miles, Geology 1966. 1966f: Partridge River Sheet, District of Cochrane; Ontario Dept. Mines, Prelim. Geol. Map. P.376, scale l inch to 2 miles, Geology 1966. 1967a: Little Long Rapids Sheet, District of Cochrane; Ontario Dept. Mines, Prelim. Geol. Map. P.396, scale l inch to 2 miles, Geology 1966. 1967b: Kapuskasing Sheet, Districts of Cochrane and Algoma; Ontario Dept. Mines, Prelim. Geol. Map. P.398, scale l inch to 2 miles, Geology 1966. Bennett, G., Brown, D. D., George, P. T., and Leahy, E. J. 1967: Operation Kapuskasing; Ontario Dept. Mines, MP10, p.31-35, 72. Boissonneau, A. N. 1965: Algoma-Cochrane, Surficial Geology; Ontario Dept. Lands and Forests, Map S365, scale l inch to 8 miles. Surficial geology 1962-1963. 1966: Glacial history of northeastern Ontario: I. The Cochrane-Hearst area; Can. J. Earth Sci., v. 3, no. 5, p.559-578. Borron, E. B. 1890: Report on the basin of Moose River; Ontario Legislative Assembly, Sessional Paper, no. 87,1890. Brown, D. D., Bennett, G., and George, P. T. 1967: The source of alluvial kimberlite indicator minerals in the James Bay Lowland; Ontario Dept. Mines, MP7,35p. Craig, B. G. 1969: Late-glacial and postglacial history of Hudson Bay; In Earth Science Symposium on Hudson Bay, P. J. Hood (ed.), Geol. Surv. Can., Paper 68-53, p.63-77. Dana, E. S., and Ford, W. S. 1966: A Textbook of Mineralogy, 4th ed., John Wiley and Sons, Inc., New York, p.558. Dawson, J. B. 1964: An aid to prospecting for kimberlites; Econ. Geol., v. 59, no. 7, p.1385-6. Deer, W. A., Howie, R. A., and Zussman, J. 1962: Rock-Forming Minerals, v. 5, Non-Silicates, Longmans, London, p.30. Edwards, N., and Gratton-Bellew, P. 1969: Report on the Coral Rapids (Canada) investigation for Selection Trust Exploration Limited, Ontario Dept. Mines and Northern Affairs, Assessment Work Library, File no. 2.133, 15p. dated Dec. 1969. Accompanied by maps and figures. Fahrig, W. F., and Wanless, R. K. 1963: Age and significance of diabase dike swarms of the Canadian Shield; Nature, v. 200, no. 4910, p.934-937. Gaucher, E. G. 1968: Magnetic properties and gravity of selected anomalies; in A Preliminary Study of the Moose River Belt, Northern Ontario, Geol. Surv. Canada, Paper 67-38, p.12-36. 55 Heavy Mineral Indicators of the Moose River Basin

Gittins, J., Maclntyre, R. M., and York, D. 1967: The ages of carbonatite complexes in Eastern Canada; Can. J. Earth Sci., v. 4, no. 4, p.651-55. Gold, D. P. 1968: Natural and synthetic diamonds and the North American outlook; Earth and Mineral Sci., v. 37, no. 5, p.37-43, illus., tables. Gunn, C. B. 1967a: The origin of diamonds in drift of the north central United States: a discussion; J. Geol., v. 75, no. 2, March, p.232-233. 1967b: Provenance of diamonds in the glacial drift of the Great Lakes region, North America; unpublished M.Sc. thesis, University of Western Ontario, London, Canada, 132p. 1968: Relevance of the Great Lakes discoveries to Canadian diamond prospecting; Cana dian Min. J., v. 89, no. 7, p.39-42. Gurney, J. J., and Ebrahim, S. 1973: Chemical composition of Lesotho Kimberlites; in Lesotho Kimberlites, ed. b. P. H. Nixon, Lesotho National Development Corporation, p.280-284. Hobbs, W. H. 1899: The diamond field of the Great Lakes; J. Geol., v. 7, p.375-388, reprinted in Precambrian, v. 26, no. 3, March 1953, p.16-20. Hogg, N., Satterly, J. and Wilson, A. E. 1952: Drilling in the James Bay Lowland: Part I, Drilling by the Ontario Dept. of Mines; Ont. Dept. Mines, 61st Ann. Kept., v. 61, pt. 6, p.l 15-40, (published 1953). Hughes, O. L. 1965: Surficial geology of the Cochrane district, Ontario, Canada; in International Studies on the Quaternary, H. E. Wright Jr., D. G. Frey (eds.), Geol. Soc. Am., Spec. Paper 84, p.535-565. Innes, M. J. S., Goodacre, A. K., Weber, J. R., and McConnell, R. K. 1967: Structural implications of the gravity field in the Hudson Bay and vicinity; Can. J. Earth Science, v. 4, p.977-993. Keele, J. 1920: Mesozoic clays and sand in northern Ontario; Geol. Surv. Can., Sum. Rept., pt. D. p.35-39. Lee, H. A. 1965: Investigation of eskers for mineral exploration; Geol. Surv. Can., Paper 65-14, p.1-17. Lee, H. A., and Lawrence, D. E. 1968: A new occurrence of kimberlite in Gauthier Township, Ontario; Geol. Surv. Canada, Paper 68-22,16p. McDonald, B. C. 1969: Glacial and interglacial stratigraphy, Hudson Bay Lowland; in Earth Science Symposium on Hudson Bay, P. J. Hood (ed.), Geol. Surv. Can., Paper 68-53, p.78-99. 1971: Late Quaternary stratigraphy and deglaciation in eastern Canada; in The Late Cenozoic Glacial Ages, Karl Turekian (ed.), Yale University Press, p.331-353. McLearn, F. H. 1927: The Mesozoic and Pleistocene deposits of the Lower Missinaibi, Opasatika, and Mattagami Rivers, Ontario; Geol. Surv. Can., Sum. Rept. 1926, pt. C, p.16-47. Norris, A. W., Sanford, B. V., and Bell, R. T. 1968: Bibliography on Hudson Bay Lowlands: Geol. Surv. Can., Paper 67-60. Northern Miner 1968a: To seek diamonds in Montreal area; Jan. 18,1968, p.13 (53). 1968b: Kirkland Lake area attracts stakers hoping for diamonds; Mar. 7, 1968, p.l, 16 (185,200). 1968c: Plan drill program in Montreal areas; Mar. 14, 1968, p.3 (243). ODM-GSC 1964: Aeromagnetic Series, Map 2306G, Coral Rapids, Cochrane District, scale l inch to l mile. 56 Prest, V. K. 1970: Quaternary geology of Canada; in Geology and Economic Minerals of Canada, R. J. W. Douglas (ed.), Geol. Surv. Can., Econ. Geol. Kept. no. l, p.677-764. Rucklidge, J. 1967: A computer program for processing microprobe data; J. Geol., v. 75, no. l, p.126. Sanford, B. V., Norris, A. W., and Bostock, H. H. 1968: Geology of the Hudson Bay Lowlands (Operation Winisk); in Geol. Surv. Can., Paper 67-60, p.1-45. Satterly, J. 1948: Geology of Michaud Township; Ontario Dept. Mines, 57th Annual Repi., pt. 4, p.13. 1971: Diamond, U.S.S.R. and North America, a target for exploration in Ontario; Ont. Dept. Mines, Misc. Paper 48, 43p. Skimming, T. 1960: Unpublished report on kimberlite indicator minerals, James Bay Lowland; Selco Expl. Co. Ltd., Toronto. Skinner, R. G. 1971: Quaternary stratigraphy of Moose River basin, Ontario, Canada; PhD. thesis, University of Washington, 9 Ip. 1973: Quaternary stratigraphy of the Moose River Basin, Ontario. Geol. Surv. Can., Bull. 225. Stockwell, C. H., McGlynn, J. C., Emslie, R. F., Sanford, B. V., Norris, A. W., Donaldson, J. A., Fahrig, W. F., and Currie, K. L. 1970: Geology of the Canadian Shield, in Geology and Economic Minerals of Canada; R. J. W. Douglas (ed.), Geol. Surv. Can., Econ., Geol. Repi. no. l, p.43-150. Tremblay, M. 1963: Report of operations within the exploratory licence of occupation area 13304, Coral Rapids area, being parts of the Townships of Hobson, Ophir, Valentine, Heath, Pitt, and Wacousta, District of Cochrane for Canadian Rock Company Limited; Ontario Dept. of Mines and Northern Affairs, Assessment Work Library, File no. 83.1-30,16p. Tyrrell, J. B. 1916: Notes on the geology of Nelson and Hayes Rivers; Roy. Soc. Can. Trans., Ser. 3, v. 10, sec. 4, p.1-27. Watson, K. D. 1955: Kimberlite at Bachelor Lake, Quebec; American Mineralogist, v. 40, p.565-579. 1967: Kimberlites of eastern North America; in Ultramafic and related rocks, P. J. Wyllie, ed., John Wiley b Sons, New York, 464p. Wilson, H. D. B., and Brisbin, W. C. 1965: Mid-North American ridge structure; in Geol. Soc. Am., Abstracts for 1965, Special Paper no. 87, p.186-187. Wilson, W. J. 1906: Reconnaissance surveys of four rivers southwest of James Bay; Geol. Surv. Can., Ann. Rept., 1902-1903, v. 15, Repi. A, p.222-243.

57

INDEX

PAGE PAGE Abitibi Canyon Mafic Complex ...... 12 Dikes ...... 3,4,8,9,10 Abitibi River Formation ...... 9,10 Chemical analyses, table ...... 11 Access ...... 1-2 Diopside ...... 24,29 Acknowledgments ...... 2 Chemical analyses, table ...... 29 Adam Till ...... 15,18,19,21,32 Drumlinoid landforms ...... 18 Direction of ice movement, sketch map of .. 16 Drumlins ...... 6 Alkalic rocks ...... 12 Alluvial deposits ...... 19,21,31 Epidote ...... 22,24,29 Analyses Eskers ...... 6,17,18,20,21,34-45 Chemical, tables ...... 11,29,30,35,36 Abundance variation, figures . .38,39,42,43,44 Electron microprobe, table of ...... 28 Trace element analyses, tables ...... 35,36 Anglo American Corp. of South Africa Ltd., analyses by ...... 4 Faults ...... 8,12 Apatite ...... 8,22 Fluorite ...... 9 Aquitaine Co. of Canada Ltd., survey by ...... 33 Fluting, glacial ...... 6,15,18 \rchean ...... 6,12,34 Fluvial sediments ...... 15 Argillite ...... 34 Fossils ...... 22 kgillite-siltstone ...... 37,40 Vrgor Carbonatite Complex ...... 8,12 Gabbro ...... 8 krite ...... 22 Garnet ...... 22,24,26-29,32 iarlow-Ojibway (glacial lake) Photos ...... 25,27 deposits ...... 18,22,41,45 Pyrope ...... 3,4,12,24,26,29,30 Photo ...... 17 Microprobe analyses, table ...... 28 Geochemistry: iasalt ...... 10,37 of esker dasts and heavy minerals ...... 34-45 Jell Sea (post-glacial) ...... 15 Geology Quaternary ...... 4,6,13-18,19,31,32 Canadian Rock Co. Ltd., work by ...... 3 Regional ...... 6-18 Carbonatite rocks ...... 8,12 Geophysical surveys ...... 32-33 Cargill Carbonatite Complex ...... 12 Glaciofluvial deposits ...... 13,17 Chalcopyrite ...... 22,45 Glaciolacustrine deposits ...... 18 Chemical Analyses Gneiss ...... 6,8,10,12 Diopside, table ...... 29 Goldray Carbonatite Complex ...... 8,12 Esker clasts, table ...... 36 Granite ...... 8,10,37,40,41,45 Heavy Minerals, table ...... 35 Granodiorite ...... 8 Ilmenite, table ...... 30 Granulite ...... 8,12,21,31 Ultramafic dikes, table ...... 11 Gravel ...... 17,19,20,31,41 ;hert ...... 34,40 Greywacke ...... 34,37,41 Ihrome diopside ...... 4,24,29 '.hromium ...... 29 Jay ...... 9,41,45 Hard Metals Canada Ltd...... 4 Hay-gravel ...... 41 Heavy Minerals lay-Howells Carbonatite Complex ...... 8,12 Investigation of ...... 18-30 lay-silt ...... 18 Photo heavy mineral fraction ...... 23 lay till ...... 18 Separation of ...... 20-22 Cochrane Ice Sheet ...... 18 Photos ...... 19,21 ionglomerate ...... 9 Trace element analyses, tables ...... 35,36 ionrad Discontinuity ...... 12 Hematite ...... 22,24 k)pper ...... 34,37,40,41,45 setaceous rocks ...... 8,9 Ilmenite ...... 4,10,24,30 Chemical analyses, table ...... 30 •acite ...... 37 Intertill units ...... 13 tevonian rocks ...... 8,9,33 •iabase dikes ...... 8 James Bay Lowland, photo ...... 5 59 Heavy Mineral Indicators of the Moose River Basin

PAGE PAGE Kapuskasing Gravity High ...... 12-13 Pleistocene geology Kapuskasing horst structure ...... 8,12,31 See: Quaternary geology Kimberlite ...... 26,32 Precambrian rocks ...... 6,17,31,45,4f Dikes ...... 3,4,10 Pyrite ...... 22,4* Indicator minerals ...... 3,18,19,24-31,34 Pyrrhotite ...... 4* Pipes ...... 3,13,32,33 Kipling Tffl ...... 15 Quartzite ...... 40,41 Kipling-Cochrane Till ...... 18,21,37,40,41 Quartz monzonite ...... J Quaternary geology ...... 4,6,13-18,19,3: Lacustrine deposits ...... 6,13,15,22 Rock stratigraphic units, table of ...... l* Lake Barlow-Ojibway, glacial ...... 18 Transport patterns ...... 31 Lake Ojibway, glacial ...... 18 Lamprophyre ...... 31,32 Regional geology ...... 6-li Dike ...... 10 Rhyolite ...... 3" Sill ...... 9 Rhythmites ...... 13, l' Lead ...... 34,37,40,41,45 Rutile ...... 24,3( Lee Geo-Indicators Ltd...... 1,2 Lignite ...... 9 Sand ...... 9,15,17,18,15 Limestone ...... 22 Sandstone ...... 5 Limonite ...... 22 Sediments, varved ...... li Lithologic units, table of ...... 7 Selco Exploration Co...... ; Serpentine ...... 9, K Magnetite ...... 8,9,10,22 Sextant Formation, Lower Devonian ...... 9, K Maps, Geological ...... back pocket Shale ...... 9,2; Direction of ice movement ...... 16 Sills ...... 5 Marine clay ...... 13 Silt ...... i: Marine deposits ...... 13,15 Silt-clay rhythmites ...... 13, l' Matachewan Dikes ...... 8 Siltstone ...... 5 Mattagami Formation, Cretaceous ...... 9 Silurian ...... ! Metamorphic rocks ...... 6,8 Silver ...... 34,37,4: Metasediments ...... 12 Sphene ...... 2; Metavolcanics ...... 12,34 Staurolite ...... 2; Felsic ...... 45 Striations, glacial ...... 1. Mafic ...... 45 Sulphides ...... 37,41 See also-. Volcanic clasts Seel also: Chalcopyrite, Molybdenite, Microscopic analyses ...... 24 Pyrite, Pyrrhotite Table ...... 28 Migmatite ...... 6 Teetzel Carbonatite Complex ...... 1; Missinaibi Formation, Quaternary .. 15,19,20,22 Terminal moraine ...... l' Molybdenite ...... 45 Thomsonite (fibrous zeolite) ...... ' Molybdenum ...... 34,37,45 TiU ...... 13,15,17,20,31,33,37,41,4 Topography Natural Resources ...... 4-5 Tyrrel Sea, (post-glacial) ...... 1. Nickel ...... 34,37,40,41,45 Ultramafic rocks ...... 9-1 Chemical Analyses, table ...... l Ordovician rocks ...... 8 Upper Canada Mines Ltd...... 4, l1 Paleozoic-Precambrian boundary .. 5,17,20,45,46 Volcanic clasts, felsic, mafic ...... 6,34,37,40,4 Paleozoic rocks ...... 4,31,45,46 Peat ...... 13 Zeolites (Thomsonite) Pinard Moraine ...... 6,17,18 Zinc ...... 34,37,40,41,4

60

Moose River Basin Chart A—Figures 2 and 3

l i'' i f'——t -'P1 l .X'i f x ' r V'T^'

LEGEND

ID Mesozoic rocks.

9 Paleozoic rocks.

B Carbonatite complex.

7 Fe/sic intrusive rocks.

e Migmatites.

5 Granulites.

4 Mafic intrusive rocks.

3 Metasediments.

2 Felsic metavolcanics.

1 Mafic metavolcanics.

SYMBOLS

Major fault.

Gravity contour in mitiigals.

Kapuskasing Gravity High.

830 SMC 12985 Scale 1 inch to 16 miles (1.1,01 3, 760)

FIGURE 2—Regional geology with superimposed contours showing the Kapuskasing Gravity High.

B3 " SMC 12986 Scale 1 inch to 1 6 miles O 1.01 3, 760)

FIGURE 3—Regional aeromagnetic map. Map 2334 MOOSE RIVER BASIN Heavy Mineral l indicators

ONTARIO DIVISION OF MINES HOMOURABLE LEO BERNIER Minister of Natural Resources OR l K REYNOLDS, Deciuty Minister of Natural Resources G A Jewett, Executive Director Division of Mines E, G. Pye, D/recfor Geological Branch Map 2334 Heavy Mineral Indicators MOOSE RIVER BASIN JAMES BAY LOWLANDS

1:25,1440 or l Inrh to 4 Miles

SAMPLE LOCATION

Alluvium. LOWER CRETACEOUS OR UPPER JURASSIC Kipling-Cocnrane ti!i(KT)and outwash. Mattagami Formation - Kaolinitic quartz sand, fireclay, clay, lignite. Massive to stratified esker node grave/ft i. UNCONFORMITY PALEOZOIC LOWER TO UPPER DEVONIAN UnsubaiYided. Upper Abitibi River Formation, fos- Note: Numbers following symbols are sample numbers referred io in the text and tables. silifercus limestone. Middle Abitibi River Formation (Moose fl/vter Formation); ncn fen- si/ifeious limestone, shale, gypsum, DISTRIBUTION OF lla Sextant Formation: sandstone, PYROPE GARNETS IN arkose. ALLUVIAL AND ESKER SEDIMENTS

Pyrope discoveries reported by T, Skim ming, Se/co Exploration Company Ltm-

Pyrope discoveries reported oy M, Trem- , Canada ROCK Company Limited ARCHEAN AND PROTEROZOIC DIABASE Pyrope discoveries recorded oy this study.

INTRUSIVE CONTACT Note: Number following symbols indicate vi pyrope grains in tnc sample. PROTEROZOIC CARBONATITE COMPLEXES 8 Carbonatite, bto!itc-pyroxene-car- tionate rock, pyroxenite, syenite, gabbro.

GARDINER J! /nferred outline of drift-cove red meta- valcanic belts determined by correlation of esker pebble count data with aero FAULT CONTACT magnetic maps, FELSIC INTRUSIVE ROCKS \4inerai occurrences ir, heesy miners! fractions (py ^ p/nte-gcethite; cp chalcopyrite; sp - sphalerite; ua = 6 Massive and foliated granitic rocxs, barite; hem = hematite). granite pegmatite. Ratio of Paleozoic blocks and smaller INTRUSIVE CONTACT pieces (in black) io Precambrian blocks ULTRAMAFIC INTRUSIVE ROCKS and smaller pieces (in white) from allu vial samples usually close to bedrock. 5 Gabbro, metagabcro, anorthosdic gabbro, peridotite, serpentinite. Outline of area covered by Aquiiairte Company o/ Canada high sensitivity aeromagnetic survey. MIGMATITE-METASEDIMENTARY- METAVOLCANIC COMPLEX METAL AND MINERAL REFERENCE 4 Biottte-ouartz-feldspar gneiss, am f i, H-py.h phibolite, quartz-mice schist, fi Fe ,...... Iron mag ,.,.... Magnetite brid©granitic gneiss, lit-oar-litorsnite gyp.....,.. .Gypsum Nb., .. ,,., .Niobium METAMORPHIC CONTACT kaol ...... Kaolinite Ni. . . ., ., , .Nickel METASEDIMENTS f /O*259 Mg,...... ,. .Lignite Si, . ,....., Silica 3 Greywacke, arkose, quartzite, am phibolite, phyllite. SOURCES OF INFORMATION FELSIC TO INTERMEDIATE METAVOLCANICS Geology and legend from Maps 2161,2166and 2171 o the Geological Compilation Series, Ontario Depart 2 Rhyolite, dacite, trachyte Hows and ment of Mines. Scale 1 inch to 4 mites.

theological data compiled Dy Dr. W.J. Wolfe and Dr. H.A. Lee, W73. MAFIC TO INTERMEDIATE METAVOLCANICS Cartography by C.A. Love anti assrsfa/vK, Surveys 1 Andesite, basait;massise tc foliated and Mapping Branch, 1975. flows, pillowed lavas, amphibolite, amphibole schist, chlorite schist, mafic tuff.

NO OUTCROP

^Rapids "-OJ*"^"' aap,tt

NO OUTCROP

Mo- L ,0xbav. Kaput, l J Richter J -^

^sb n