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 DEPARTMENT OF MINES

HON. JAMES E. MALONEY, Minister D. P. DOUGLASS, Deputy Minister M. E. HURST, Provincial Geologist

Niobium-Bearing Complexes East of Lake Superior

By G. E. PARSONS

Geological Report No. 3

TORONTO Printed and published by F"rank Fogg, Printer to the Queen©s Most Excellent Majesty 1961

TABLE OF CONTENTS Geological Report No. 3

PAGE Abstract...... viii

CHAPTER I INTRODUCTION General...... l Previous Geological Work and History of Discoveries...... , ...... 2 Nomenclature...... 3 Mineralogy and Geochemistry...... 4 General Geology...... , ...... 6 Origin and Age of Carbonate-Alkali ne Complexes...... 6

CHAPTER II SEABROOK LAKE AREA I introduction...... 11 Location and Access...... 11 History and Previous Work...... 11 Present Mapping...... 12 Topography...... 12 General Geology...... 12 Table of Formations...... 13 Description and Distribution of Rock Types...... 13 Granite...... 13 Diabase...... 13 Fenitic Granite and Granite Breccia...... 13 Ijolite, Biotite Pyroxenite, and Related Breccia...... 14 Mafic Breccias...... 18 Carbonatites...... 18 Miscellaneous Rocks...... 19 Alkaline Dikes...... : ...... 20 Structure...... 20 Mineralization ...... 20 Magnetic Data and Radioactivity...... 20 Magnetic Data...... , ...... 20 Radioactivity...... 22

CHAPTER III FIRESAND RIVER AREA Introduction...... 23 General...... 23 Acknowledgments...... 23 Previous Mapping and Work Done...... 23 Present Mapping...... 23 Topography...... 24 General Geology...... 24 Table of Formations...... 24 Description and Distribution of Rock Types...... 24 Country Rocks...... 24 Alteration of Country Rocks...... 25 Mafic Carbonate and Silicate Rocks...... 25 Calcite Carbonatite...... 26 Dolomitic Core Rock...... 26 Basic Dikes...... 27 Structure...... 27 PAGE Magnetic Data and Radioactivity...... 28 Economic Geology...... 29 Mineralization...... 29 Description of Properties...... 29 Algoma Ore Properties Limited...... 29 Morrison et al Claims...... 30 CHAPTER IV NEMEGOSENDA LAKK AREA Introduction...... 33 General...... 33 Acknowledgments...... 33 Previous Mapping and Work Done...... 33 Present Mapping. . . . . , ...... 33 Topography...... 33 General Geology...... 34 Table of Formations...... 35 Description and Distribution of Country Rocks...... 35 Country Rocks...... 35 Alteration or Fenitization of Country Rocks...... 35 Fenites...... 36 Ijolite or Ijolitic Fenite...... 36 Red Alkaline Fenite...... 36 Pyroxenide Fenites...... 36 Intrusive, Replacement, and Rheomorphic Types...... 39 Silicate Rocks...... 39 Carbonate Rocks...... 40 Igneous Contact Rocks...... 40 Syenitic Rocks and Breccias...... 40 Alkaline Intrusives...... 41 Alkaline or Nepheline Syenites...... 41 Miscellaneous Rocks...... 43 Late Mafic and Porphyry Dikes...... 43 Late Carbonate-Quartz-Chlorite Dikes and Carbonate Veins 43 Structure...... 43 Magnetic Data...... 44 Radioactivity...... 45 Economic Geology...... 45 Mineralization...... 45 Description of Properties...... 46 Dominion Gulf Company...... 46 Zone D...... 46 East Ore Area...... 49 Continental Wood Products...... 50 CHAPTER V LACKNER LAKE AREA Introduction ...... 51 Acknowledgments...... 51 Previous Mapping and Work Done...... 51 Present Mapping...... 52 Topography...... 52 General Geology...... 52 Table of Formations...... 53 Description and Distribution of Country Rocks...... 53 Country Rocks...... 53 Alkaline and Carbonate Rocks...... 53 Ijolite and Ijolitized Breccia...... 53 PAGE Foliated Ijolitic, Malignitic, and Syenitic Rocks...... 54 Carbonatite...... , ...... 54 Nepheline Syenites...... 56 Mafic Alkaline Dikes...... 58 Structure...... 58 Magnetic Data and Radioactivity...... 58 Economic Geology...... 59 Mineralization...... 59 Description of Properties...... , ...... 60 Apamag Mines Limited...... 60 Claymac Mines Limited...... 60 Dominion Gulf Company...... 60 Le Brasseur Derraugh MacDonnell Property...... 61 Multi-Minerals Limited...... 61 Nos. 3, 4, and 5 Anomaly Zones...... 61 No. 6 Body...... 63 Pyrochlore Zone in Wall of No. 6 Body...... 67 No. 8 Zone...... 67 Calcite Zone...... 68 Ontario Rare Metal Mines Limited...... 68 M. Silverman Claims...... 68 Hebden (Portage) Complex...... 68 References...... 69 Index...... 71 Map Case...... at back of report

PHOTOGRAPHS PAGE Fenitized granite with fractures filled with pyroxene. Seabrook Lake area...... 14 Fenitized granite breccia showing greenstone-like streaks. Seabrook Lake area...... 15 Foliated carbonatite in highly altered breccia. Seabrook Lake area. . . . 16 Ijolitized breccia with biotite-pyroxene-rich fragments in a lighter- coloured, nepheline-rich matrix. Seabrook Lake area...... 16 Ijolite and semi-foliated biotite pyroxenite. Seabrook Lake area...... 17 Medium-grained ijolite. Seabrook Lake area...... 17 Inclusions of red fenitized granite in a foliated carbonatite. Seabrook Lake area...... 19 Foliated carbonatite dike cutting greenstones. Firesand River area. . . . 27 Pyrochlore showing in foliated carbonatite. Firesand River area...... 30 Gabbro fractured and partly replaced by pyroxene, biotite, and nepheline. Nemegosenda Lake area...... 37 Remnant fragments of gabbro in ijolite. Nemegosenda Lake area...... 37 Syenite with poikilitic orthoclase phenocrysts in a matrix of orthoclase, nepheline, aegirite, and biotite. Nemegosenda Lake area...... 42 Drill core. Foliated carbonatite with fragments of wrall rock. Lackner Lake area...... 57 Nepheline syenite cutting feldspar-rich gneiss. Lackner Lake area. . . . . 57 Feldspathic gneiss cut by alkaline mafic dikes. Lackner Lake area. . . . . 59 Pitted weathered surface of foliated rocks of niobium. Lackner Lake area...... 63 MAPS AND FIGURES (in the text) PAGI-: Key map showing the location of the Firesand River area, the Neme- gosenda River area, and the Lackner River area...... viii Carbonate-alkaline complexes in the eastern part of northern Ontario. . 2 General composition of alkaline silicate rocks...... 4 Sections across volcanic necks in Africa and carbonate-alkaline com plexes in Ontario, east of Lake Superior...... 8, 9 Key map showing the location of the Seabrook Lake area...... 11 Ground magnetic map of the Seabrook Lake complex...... 21 Aeromagnetic sketch map, Firesand River complex...... 28 Main pyrochlore showing, Morrison et al claims. Firesand River area. . 31 Sketches from photomicrographs of partially pyroxenitized red alkaline fenite and wallastonite-bearing fenite. Nemegosenda Lake area. . . 38 Sketches of core of biotite-feldspar pegmatite-type rock. Nemegosenda Lake area...... 40 Vertical sections, Zone D, Dominion Gulf Company. Nemegosenda Lake area...... 47 Sketches of structure of malignite breccia, Dominion Gulf Company. Nemegosenda Lake area...... 48 Sketches of core of pyrochlore-bearing carbonate, Multi-Minerals Limited. Lackner Lake area...... 55 Vertical sections across Nos. 3 and 4 zones, Multi-Minerals Limited. Lackner Lake area...... 62 Vertical section through the centre of a massive apatite-magnetite body. Lackner Lake area...... 64 Vertical section through the east end of a massive apatite-magnetite body. Lackner Lake area...... 65 Vertical section through No. 8 niobium zone, Multi-Minerals Limited. Lackner Lake area...... ,...... 66

GEOLOGICAL MAPS AND CHARTS (in the map case)

Map No. 2005 (coloured Seabrook Lake area, District of Algoma. Scale, l inch to J4 mile. Map No. 2006 (coloured) Firesand River area, District of Algoma. Scale, l inch to 24 mile- Map No. 2007 (coloured) Nemegosenda Lake area, District of Sudbury. Scale, l inch to J4 mile. Map No. 2008 (coloured) Lackner Lake area, District of Sudbury. Scale, l inch to J4 mile. Chart A Map of the Lackner Lake area showing Ground Magnetic Contours.

ABSTRACT The report describes the gross geological and magnetic features of four niobium-bearing carbonate-alkaline complexes: Scabrock, Firesand, Nemegosenda, and Lackner. The accompany ing maps are on a scale of l inch to ^ mile. The Seabrook complex is Y*i square mile in area. It consists of ijolite, in situ and injected breccias, and carbonatite dikes; the country rocks are granite and diabase dikes. Niobium is present as the mineral pyrochlore, but so far no important concentrations have been located.

Scale l inch to SO miles

Key map showing the location of the Fire sand River area (map No. 20O6), the Nemegosenda River area (map No. 2007), and the Lackner River area (map No. 2008).

The Firesand complex is distinctly circular and 1^ square miles in area. A dolomite core is surrounded by calcite carbonatite interzoned with biotite-pyroxene-calcite rock and country rocks of greenstone and granite. Pyrochlore is present in the calcite carbonatite, but no potential ore zones have been denned to date. The Nemegosenda complex is 9 square miles in area; a core of nepheline syenite is surrounded by a fenite aureole. The country rocks are gneiss. Niobium is quite prevalent in the fenites; one zone is reported to contain 20,000,000 tons of 0.5 percent Nb205 , which is available for open-pit mining. Large tonnages of lower grade material are indicated. The Lackner complex is 9 square miles in area; it consists of several ring-zones of mafic silicate rocks enclosed in nepheline syenite. Pyrochlore is widespread in the mafic silicate rocks and in apatite-magnetite zones. The complex has been extensively explored, and main- millions of tons in several large zones grading from 0.17 to 0.33 percent Nb205 are reported. Niobium-Bearing Complexes East of Lake Superior Districts of Algoma and Sudbury

BY G. E. Parsons1

CHAPTER I Introduction

GENERAL The first major niobium deposit in Canada was discovered on the Manitou Islands, Lake Nipissing, Ontario, in 1952. This was quickly followed in succeed ing years by major discoveries at Oka, Quebec, in 1953; at Lackner Lake, Ontario, in 1954; and Nemegosenda Lake, Ontario, in 1955. Niobium mineralization, with a similar geological environment to that of the deposits mentioned above, has now been located in six other areas in Ontario. In 1952 the price of niobium-tantalum concentrates was doubled by an agency of the United States government, and this stimulated prospecting for niobium in Canada. The search for uranium and iron deposits, which was then at its peak, contributed to niobium discoveries, since most of the finds were originally staked for iron or uranium. The widespread use of aeromagnetic sur veys and the development of the X-ray fluorescence method of assaying for niobium speeded the search for, and evaluation of, deposits. Niobium is used at present as an additive to steel to prevent intergranular corrosion when subjected to high temperature and chemical corrosion, as an absorber of residual gases in vacuum tubes, and as carbides in blades and other parts of jet motors. It is also being used as a fuel-alloying and fuel-cladding metal in fast nuclear reactors. The chief hope for a greatly expanded market is possibly in missile production and especially in the introduction of automotive gas turbines. The locations of nine of the niobium-bearing complexes in the east half of northern Ontario are shown in the accompanying figure. This report describes four of those lying east of Lake Superior and one satellite body. The emphasis is placed on their gross geological and magnetic features, niobium mineralization, and their present state of exploration and development. The report is largely a compilation and correlation of data assembled by companies and individuals who have worked in these areas and has been made possible only by their whole hearted co-operation, for \vhich the author is deeply indebted. The project is one that actually deserves and requires several years© mapping and laboratory study for adequate coverage, and not a few months as has been attempted. However,

Consulting geologist, Toronto. Niobium-Bearing Complexes East of Lake Superior the author has spent considerable time on the Lackner and Memegosenda com plexes, particularly since 1954, so that he is not a stranger to the areas. Neverthe less, he will be the first to admit that this presentation is an inadequate treatment of a most complex and intriguing geological problem.

1. Clay Township 2. Cargill Lake 3. Firesand River 4. Nemegosenda Lake 5. Portage Lake t. Lackner Lake 7. Seabrook Lake l. Iron Island 3. Manitou Islands

Carbonate-alkaline complexes in the eastern part of northern Ontario.

PREVIOUS GEOLOGICAL WORK AND HISTORY OF DISCOVERIES On the map accompanying his report (Bell 1883) Robert Bell notes at Trout Lake (Nemegosenda Lake), an area of "red and reddish grey syenite granite with patches of grey amygdaloids containing calc-spar, fluorspar and apatite sur rounded by hornblendic schists." This is the first known description of one of the alkaline areas covered in this report. Bell made a side trip to Trout Lake while on a more extensive survey from Michipicoten to James Bay. B. F. Haanel (1909, pp. 110, 111) records the first discovery of nepheline syenite in the Lackner area when he examined the McVittie magnetite showings discovered late in the last century. T. L. Gledhill (1927, pp. 43, 44) gives the first published description of the Firesand carbonatite when he described the "Gibson Iron Claims," which were staked several years prior to 1927. Geological Report No. 3

In 1949 radioactivity was detected in the "limestone" at Seabrook Lake, and also on claims embracing the McVittie magnetite showings in the Lackner area. In 1951, H. B. Hatch of Nemegos Uranium Corporation obtained evidence of niobium in samples from the McVittie claim group. In 1953 the first niobium mineralization in the Firesand area, at Michipicoten, was detected. The first concentrated search for niobium ore zones in the areas covered by this report was made in 1954. This resulted from work carried out by Multi- Minerals Limited under H. L. Garvie on the former Nemegos Uranium Corpora tion claims in the Lackner area. By the fall of 1954 five companies were drill- testing properties in the Lackner area, and Algoma Ore Properties Limited was working in the Firesand area. In the spring of 1955 niobium mineralization was located by Dominion Gulf Company at Nemegosenda Lake. This was the first of the areas described in this report that had not been previously staked as an iron or uranium prospect. The company was attracted to the area by the results of an aeromagnetic survey, and the finding of a boulder of nepheline syenite, the year before, six miles to the southwest in Borden township. NOMENCLATURE Generally accepted terms as used in the description of similar alkaline and carbonatite rock areas throughout the world are employed in this report. These are listed below with explanatory notes: Alkali, Alkalic, and Alkaline. These terms are used in a similar sense by different authors to designate minerals and rocks relatively rich in sodium and potassium. Aegirite and Aegirine. Both terms are used for the same sodium-ferric iron pyroxene; the author has followed Dana©s System of Mineralogy and used the term aegirite. Carbonatite. The term karbonatite was introduced by Brbgger (Von Eckermann 1948) to embrace a family of carbonate-rich and silicate-carbonate rocks, which he believed to be igneous in origin and crystallizing from a carbonatic magma derived from an alkaline magma that had become enriched in CO2 by the assimilation of sedimentary limestone. Pecora (1956, pp. 1537-56), who reviewed the carbonatite problem, defines "carbonatites as, . . . a special kind of carbonate-rich rock genetically related to the alkalic rock-forming process and alkalic-magma irruptions." The author has attempted in this report to use the term only for the carbonate-rich foliated rocks that occur as distinctly definable masses with relatively sharp boundaries, and to avoid its use for what appear to be carbonate-bearing rocks of a definite metasomatic replacement type. Fenite. Von Eckermann defines this term as "in-situ metasomatically altered (without sub stantial material exchanges) older contacting rocks irrespective of composition, but the term does not apply to mobilized (rheomorphic) and transported hybridic mixed rocks even if their origin may be fenitic." Foyaite. The original Foya type from Portugal has orthoclase as its chief constituent with nepheline, sodalite, and various ferromagnesian minerals. The composition referred to in this report and in the accompanying figure is that used by Brogger and von Eckermann for their classical memoirs on Fen in Norway, and Alno in Sweden, respectively. Ijolite. This is a rather melanocratic crystalline rock consisting of nepheline and soda pyroxene. Strictly speaking it defines rocks containing about equal proportions of these two minerals; however, normally the percentages may be highly variable. Melteigite is a related type rich in soda pyroxene, and urtite is a type rich in nepheline. Juvite. This is a leucocratic variety of nepheline syenite consisting of about equal proportions of nepheline and alkali feldspar and minor ferromagnesian minerals. Here it has been used for a distinctive coarse nepheline-rich syenite in the Nemegosenda complex. Jacupirangite. This is used here for a melanocratic series of rocks consisting of varying amounts of apatite, magnetite, and pyroxene. Strictly speaking it applies to rock consisting essentially of titanian augite with accessory magnetite, apatite, nepheline, etc. Malignite. This is a mesocratic to melanocratic variety of nepheline syenite. Here it has been specifically used for rocks with about equal proportions of alkali feldspar and sodic pyroxene. Niobium (Columbium). This element, No. 41, was first named columbium; however, by inter national agreement in 1949, chemists agreed to use the term niobium, a later name for the same element. Pulaskite. This term is used for a feldspar-rich alkaline syenite with minor amounts of nepheline and mafic minerals. Sovite. The term was introduced by Brogger for the calcite-rich member of his carbonatite family. Such terms as biotite-sovite, apatite-sovite, sovitic fenite, etc. introduced by Von Eckermann are very useful names for carbonate-rich rocks in these complexes. Niobium-Bearing Complexes East of Lake Superior

MINERALOGY AND GEOCHEMISTRY A rather characteristic and diagnostic suite of minerals is encountered in these niobium-bearing, carbonate-alkaline complexes. The chief silicate minerals are alkali feldspar, nepheline, soda pyroxene, and ferrie biotite. Locally, garnets, wollastonite, and titanite are also present. The chief carbonate is calcite; however, dolomitic, ferruginous, and mangani- ferous types are present or indicated. The simple oxides include magnetite, ilmenite-magnetite, and hematite. The sulphides pyrite and pyrrhotite are common minor accessory minerals. Occasionally sphalerite, chalcopyrite, and galena are noted.

General composition of alkaline silicate rocks.

Other minerals present in varying amounts are apatite, zircon, scapolite, sodalite, zeolites, pyrochlore, fluorite, monazite, olivine, serpentine, barite, and riebeckite. Certain mineralogical and geochemical characteristics and tendencies warrant special notation, as for example: The feldspars are all of the alkali (Na,K) types; Ca in silicate form is found in such minerals as garnet, wollastonite, and titanite. The mafic minerals are generally Na or iron-rich types or both, such as aegirite and aegirite-augite or ferrie biotite. Quartz is absent except as a secondary mineral in faults, and the silica- deficient mineral nepheline is abundant in the silicate rocks. In some complexes Ca is abundant in the form of carbonates and locally also as apatite. Geological Report No. 3

W q 0 0 o o -d 0 0 -6 H .0 "O 10 1C ^ IO - ~ " - Z O en ^ Ci o ro*} o 0 o o o o 0 j ^o CD o oo ^^ -s; ^ t ^""^ CN oo CN U 0 0 o O 0 O 0 g o O 0 Q - U c CN OO ©t CN 00 -t Ci 8 8 ^^ i. CN

cr. 2 Q. o 0 0 a o 0 O 0 0 "^^ i-O r^ R o R -f S H o o 1C o IO Z c -H " o g w U s fc K E O o 0 o o 0 o O o CM C IO rs CN "t CN CN L- ^ ^ o C/l ^ OJ w a S Ml ci o o o O o O *3^ U o o 8 o o o O ci rt tt, 8 o o 1C O MM O. 1 ^0 VO o ro ~ f~ C? ^c ^ Q Z in APUSKASI 1C o o 0 0 o O 0 SELECTE CN oo o oo 1C o oy rt * l CN 8 CN tn rt "rt 0 0 o 0 0 O 0 O 0 o O co 8 o o 8 o 8 8 O O ~* ^•V* tn IO IO \o IO H^4 C1J 1-1 o 0 O O o C CN rt CN CN -* 2•a; W K i o o o O o 0 0 0 o c o o o O o ^5 ^5 ^^ 0 H *o t^ IO IO IO S" o CN- O O O Z ^ CN "^ fN fN ^- c ~ w OJ H P E Z b* Z u -C M rt rt ©S 1 rt ci a o Is Z c l m O a; 2 Q U w .2'C CM rt ^i UH carbonatitedikecuttingbreccia;maficas 500ft.NW.ofNo.2claimoutcroppostan Multi-MineralsD.H.NX2;carbonatited O C/} 35-ft.wide,carbonatitedikeacutcoarse carbonatitedikecutting(Morrgreenstonea 700W.ft.ofNo.2claimoutcroppost,an 78;brown-weathering carbonatewithwhite MattagamiMiningcalcite-magnetitebody. 6 wing)actinolite,magnetite,andpyrochsome; ClaymacD.H.No.2;carbonatitedike whitecalcite;visiblepyrochloreindike.rse ofcalcitewithoutcropcoarsesomecoarsen IX w OJ silicates,darkmagnetite,andpyrrhotiteaor H ni *^ Z -t; 'o gnetite,hematite,anddarksilicates. a J CJJ )78;brown-weatheringcarbonate. H r U Remarks H H O t/2 Z xrt" ite,apatite,andbiotite. o ^ en nite;minorapatite. o U4 ©f. ©porphyroblasts."i ci t/T ^ C w rt z x 'o w - ? *— J M-" f| f^ CM S tt. S CM 0 O u -C ©c r g.- M en E u E g g ^ 4J C r-M C n H C QJ K w X O bc o E 8* O CN O O CN o t: O cj o tn Jn z JJ tl, i fe fe U, b tu fi. tn .i w J2 "2 0 o u z g o o D - ^j rt rt rt o ,o U en t/i v **" S X! .c o -^ be 3 u o .h rt T3 "O CM J CO c/) d, J U U C C -t; i ^^ ^^ Ci " ^- O d o ci H "o. i: U W U, S ^ U ffi c O CM 3 c^ Niobium-Bearing Complexes East of Lake Superior

A distinct accumulation in these complexes of such elements as Na, K, Ca, Fe, Ti, P, Zr, Mn, C, Nb, U, Th, Ce, F, Ba, and Sr is indicated. Spectrographic analyses were made on hand-picked carbonate grains from nine samples of carbonatites from the area east of Lake Superior described in this report, and from the Kapuskasing area. The results are tabulated in the accompanying tables. Partial chemical analyses were made on six samples, and these are presented in the second table. These analyses were all made by the Provincial Assay Office. Although the data are insufficient to draw any definite conclusions, a distinct pattern for the minor constituents in the carbonates of alkaline and related carbonatite areas mav exist.

QUANTITATIVE SPECTROGRAPHY ANALYSES OF CARBONATITE ROCK SAMPLES (The selected carbonate samples for the analyses in the previous table were taken from these samples, and the sample numbers correspond in both tables.)

Sample No. Area Al 20;i Si02 MgO Fe203 percent percent percent percent A ...... 0.04 5.40 1.11 1 59 B...... 0.03 2 45 0.56 1.26 C.... 0.05 1.17 1.17 1.90 D...... 0.13 3 95 0.77 1.93 E...... ,...... 2.28 13.7 6.25 4.20 G...... Lackner 0.15 1.14 0.17 0.59

GENERAL GEOLOGY The locations of the known niobium-bearing carbonate-alkaline complexes in the eastern part of northern Ontario are given in the figure on p. 2. They cut a variety of rock types, and there is no evidence of regional or local structures determining their distribution. Six of the nine shown on the figure fall in a belt trending slightly east of north, which is more or less at right angles to the Keewatin-Timiskaming fold axis. This corresponds, in some respects, to the situation in eastern Quebec where the belt of the Monteregian Hills trends at right angles to the Appalachian fold axis. It has been suggested by several authors that a belt of alkaline complexes may extend northwestward from the Monteregian Hills, through the Lake Nipissing and Chapleau occurrences, to Port Coldwell on the north shore of Lake Superior. The evidence now indicates that the complexes in the area east and north of Lake Superior may eventually be found to trend, in belts, in a northerly direction, which is almost at right angles to the Monteregian trend. The complexes described in this report range from predominantly carbonate to predominantly alkaline silicate types. While some are characterized by few rock types, others like Nemegosenda have many rock types. The following table briefly summarizes some of their features, and the cross-sections, on pages 8 and 9, illustrate their similarity to some of the African volcanic complexes.

ORIGIN AND AGE OF CARBONATE-ALKALINE COMPLEXES Until recently, geologists in North America have generally explained the carbonates in carbonate-alkaline complexes as originating from sedimentary limestones, and the associated alkaline rocks as a product of reaction between Geological Report No. 3

FEATURES OF CARBONATE-ALKALINE COMPLEXES

Dominant Rock Types Name Size (roughly in order Country Rock (square miles) of abundance)

3/10 (satellite of Lackner) Biotite-pyroxene- carbonate rock y* diabase dikes Biotite-pyroxene- carbonate breccias Fenitic breccias Carbonatites \y± greenstones Biotite-pyroxene- carbonate rocks

Nemeerosenda ...... 9 Nepheline syenite Gneiss Hydrated red fenite Pyroxenitic fenite plus additional and most of above types

Lackner. Nepheline syenite Gneiss and Matachewan Foliated ijolitic malignitic diabase and syenitic rocks Ijolite breccias plus miscellaneous additional types

limestone and intrusives. The two better-known Canadian carbonate-alkaline areas, such as those on the Manitou Islands, Lake Nipissing, and at Oka, Quebec, are sufficiently close to areas of Grenville-type limestones that the authors of papers on these areas could refer to this limestone to explain the foliated carbonate rocks. However, in the case of the complexes described in this report, the widely scattered and isolated occurrences of alkaline and carbonate rocks cutting Keewatin greenstone, granite, diabase, and gneiss, and the lack of sedimentary limestone as a source carbonate, would indicate that the carbonates are not of sedimentary origin. The field evidence also reveals conclusively that the car bonates are magmatic in origin and not sedimentary. The statement of Dixey, Smith, and Bisset on the origin of the limestone in the volcanic necks in Nyasaland (figure on p. 9) seems equally applicable here. They state: "Without claiming for these limestones a mode of emplacement similar to that of ordinary intrusions one may confidently regard them as of magmatic origin and comparable to the magmatic limestones or carbonatites of Alno in Sweden, and of the Fen district in Norway." Von Eckermann (1948) postulated for the Alno area a magmatic melt or liquid "consisting of mainly carbonates, predominantly potassic and containing as additional essential components: lime, magnesia, alumina, iron, titanium and phosphorus, as well as free carbon dioxide, much fluorine and comparatively little water" as the cause of the explosive effects, of the fenitization, of the carbonatites, and finally of the intrusives. The evidence in the complexes under consideration certainly suggests a similar type of origin, although the abundance of nepheline and aegirite in some of the complexes indicates that there may be more soda present than might be derived from the country rocks. Niobium-Bearing Complexes East of Lake Superior

^ Carbonatite

NAPAK VOLCANO, UGANDA

Fractured, pyroxenttized and nvphelinized. Ijolite Gradational contact Biotitized, carbonated zones PORTAGE LAKE, ONTARIO

Carbonatite Ijolite, pyroxenite; breccia

ite, diabase dikes

Breccia Gradational contact, fenitized (granite and diabase fragments Mafic bre in a pyroxenitized matrix.) (biotite, pyroxene, calcite Breccia and secondary minerals.) (fragments, mostly iranite; carbonated, ferruginous.) CORE SOUTH APPENDAGE

SEABROOK LAKE, ONTARIO

. Keewatin greenstone (basic lava).©//, syenite, granite. i Ferruginous, dolomitic Calcite carbonatite Biotite-pyroxene- carbonatite plus. carbonatized rock; plus pyroxenitized greenstone. FIRESAND RIVER, ONTARIO

Scale of Miles l

Sections across volcanic necks in Africa and carbonate-alkaline complexes in Ontario, east of Lake Superior. (References: (a) B. King, "The Napak Area of Southern Karamoja, Uganda," Memoir V, Geol. Surv. Uganda, 1 948; (e. f, g) F. Dixey, W. C. Smith, and C. B. Bisset, "Chilwa Series of Southern Nyasaland," Geol. Surv. Nyasaland Protectorate, 1955.)

8 Geological Report No. 3

\ Limestone, agglomerate, Impregnated with feldspathic material; breccia, feldspar rock. replaced by pyroxene; shattered.

CHILWA ISLAND, NYASALAND

Nepheline Nepheline syenite syenite

v© © Gneiss * Tinguaite Limestone, feldspar ~ rock, agglomerate

TUNDULU NECK, NYASALAND

MAUZE HILL

Syenrte and /A < Limestone i gneiss x, riddled with red feldspar rock g SONGWE AND MAUZE HILLS, NYASALAND

.Sovite(carbonate) breccia Malignite masses and dikes y y Jacupirangite and biotite-feldspar breccias l in breccia zone

* Nepheline syenite nitic fenite l alkaline (foliated ijolite) (Orthoclase phenocryst J Feldspathic breccia plus and aegirite in red ; (feldspar, nepheline, calcite.) hydrated matrix) \© v v Syenite contact breccia

NEMEGOSENDA LAKE, ONTARIO

Scale of Miles Niobium-Bearing Complexes East of Lake Superior

The evidence in these and related complexes suggests the following very general and much-simplified sequence of events in their formation: 1) Drilling of a central diatreme by explosive gases, and possible ejection of volcanic rocks. 2) Alkaline metasomatism of the country rocks, creating fenites, ijolites, etc. 3) Carbonatization of the volcanic rocks in the neck and the fenites; the emplacement of carbonatites in the central diatreme and ring-like zones around it. This may be restricted to the upper parts of the complex. 4) Emplacement of nepheline syenite especially at depth. The accompanying sections taken across some African and Ontario carbonate- alkaline complexes are intended to illustrate this sequence, that is, a series of types ranging from volcanic necks to intrusive plugs.

Age No rocks are known to cut the five carbonate-alkaline complexes described in this report. The youngest rocks cut by them are diabase dikes considered to be Matachewan in age, although some may be early Keweenawan. In the Cargill complex, in the Kapuskasing area, a pyroxenite mass associated with, and cut and altered by, carbonates is definitely cut by a northeast-trending diabase dike that is probably Keweenawan in age. If this pyroxenite is an early facies of this Cargill complex, as is highly probable, then it must be concluded that this complex was emplaced prior to the Keweenawan diabase dike. The northerly trend of the belts of these alkaline complexes, as mentioned in the last section, suggests a relation to the Matachewan diabase dikes that have a similar over-all trend, especially in the Chapleau area and an extensive region to the east and north of it. In this respect, Dixey, Smith, and Bisset (figure P. 9) consider that the Nyasaland volcanic necks closely followed the emplacement of north-south-trending dolerite dikes. The complexes in Lake Nipissing are older than the adjacent Ordovician sediments, which indicates they may be Precambrian in age and hence not related to the Post-Devonian (Tertiary?) Monteregian Hills of the Appalachian region. In conclusion, it may be stated the carbonate-alkaline complexes of the Lake Superior area are definitely younger than diabase dikes of Matachewan age, and possibly older than olivine diabase dikes of Keweenawran age. They are probably related in age to the Sudbury nickel irruptive or the Keweenawan period of volcanism, or both.

10 CHAPTER II Seabrook Lake Area

INTRODUCTION

Location and Access Seabrook Lake is in the southwestern part of Township 5E, District of Algoma. The carbonate-alkaline complex is at the south end of the lake. The area is readily accessible by an old lumber road, which branches off the Thessalon-Chapleau highway (the Mississagi Road) opposite Aubrey Falls on the Mississagi River.

Sole l inch lo 50 miles

Key map showing the location of the Sea brook Lake area (map No. 2005).

History and Previous Work W. D. Harding (1950), during his reconnaissance mapping along the Mississagi Road in 1949, also examined the rocks along the shore of Seabrook Lake. In the same year, prospecting, which was prompted by uranium discoveries in 1948 north of Sault Ste. Marie, and by the opening of the Mississagi Road, resulted in the discovery of radioactivity at Seabrook Lake and also at Aubrey Falls, six miles southeast. Harding describes the Seabrook Lake discovery as giving high geiger counter readings from a band of crystalline limestones on the west shore of the lake. W. Bussineau and others have prospected and held claims in the heart of the area for several years. They carried out bulldozer stripping, which has greatly increased the amount of exposed rock; their work was mostly devoted to extending showings of a hematite-bearing rock. 11 Niobium-Bearing Complexes East of Lake Superior

The first indication of niobium mineralization was obtained by George Gilbert of Algoma Ore Properties Limited from a sample rich in magnetite that he collected early in 1954. This sample came from the northeast corner of the main peninsula in the south end of the lake, and assayed several percent niobium pentoxide. During part of 1956 and 1957, Tarbutt Mines Limited held under option claims covering the main part of the area. They completed a ground magneto meter and geological survey and some packsack drilling.

Present Mapping In the late fall of 1957 the author spent three weeks mapping and studying the area. Picket lines cut by Tarbutt Mines Limited, and air photographs, were used for control. Another week was spent in the area, in the fall of 1958, for the Ontario Department of Mines, to complete the investigation so that a map could be compiled for publication. This data is presented at a scale of l inch to ^ mile on map No. 2005 (in map case).

Topography The area around Seabrook Lake is one of rather bold relief typical of the Algoma district. The peninsula in the southwestern part of the lake marks the heart of the carbonate-alkaline complex. The arcing parts of the lake adjoining this peninsula, together with the small lakes to the south, indicate the area of brecciation between the granites and the alkaline and carbonate suite of rocks. A sharply defined north-south lineament through the heart of the area is indicated by magnetic data to be a late fault. This area is on the west edge of the region swept by the Mississagi for st fire in 1948, so that underbrush and slash are now prevalent. Outcrops are abundant, although usually of small size over most of the central part of the alkaline area, and very abundant on the south appendage.

GENERAL GEOLOGY

The Seabrook Lake carbonate-alkaline complex is one of the smaller ones so far found in Ontario. The area underlain by these rocks is little over half a square mile, although the area strongly affected by, or containing a fair proportion of these rocks is twice that size. In addition, dikes or vein-dikes of related rock types, or both, occur for several miles from Seabrook Lake. In shape, the carbonate-alkaline complex is essentially a circular body, with an appendage extending three-quarters of a mile to the south. The rocks in the complex are dominated by breccia types, and their miner alogy is dominated by pyroxene, biotite, nepheline, carbonate, and secondary minerals. Feldspar is only a minor constituent of the whole mass. Outcrops and magnetic observations indicate that the heart of the area is underlain by carbonates. Surrounding this is a heterogeneous group of rocks called mafic breccias, which are cut by many narrow foliated carbonate dikes. On the south side, and in the appendage on that side, the rocks consist of ijolites, pyroxenites, and related breccia. These rocks and the mafic breccias grade to altered and fractured country rocks. The country rocks are granites cut by diabase dikes. 12 Geological Report No. 3

TABLE OF FORMATIONS PRECAMBRIAN POST-MATACHEWAN Carbonate and Alkaline Rocks: Mafic alkaline dikes. Miscellaneous rocks. Carbonatite. Mafic breccia. Ijolite, pyroxenite, and related breccia. Fenitized granite and granite breccia. MATACHEWAN ? Diabase.

Intrusive Contact ALGOMAN ? Granite.

Description and Distribution of Rock Types

GRANITE The granite is mostly massive, uniform, and medium-grained, and consists of pink feldspar, quartz, and a small amount of biotite. Coarse pegmatitic as well as gneissic facies are sometimes present. Locally the granite is a deeper red and slightly radioactive. This granite surrounds the carbonate-alkaline complex and occurs in an extensive area well beyond it.

DIABASE Many diabase dikes are present in the surrounding country as well as in the immediate vicinity of Seabrook Lake. Only a few were mapped, to establish their general trends. They are of a dark-green, uniform, diabasic type. Some are characterized by scattered to fairly thickly packed large phenocryst^ of light-green plagioclase, which often have a rounded corroded outline. This type of dike strongly resembles some of those of Matachewan age in the type locale in the Matachewan area. With one or two possible exceptions, these dikes all strike northwest. They cut the granites, but none has been found cutting the carbonate-alkaline rocks. Some of these dikes are cut by carbonate veins, or by carbonate-mafic silicate zones, and one is cut by a distinctly feldspathoidal alkaline dikelet. They give distinct linear magnetic anomalies that terminate as the breccia zone surrounding the alkaline-carbonate area is approached. At Aubrey Falls, six miles southwest of Seabrook Lake, these northwesterly trending diabase dikes are cut by a slightly north-of-east trending dike of porphyritic diabase.

FENITIC GRANITE AND GRANITE BRECCIA In the immediate vicinity of the carbonate-alkaline rock area, and also in scattered zones around it, the granites are variously pyroxenitized and carbon- atized, or both. This pyroxene or carbonate mineralization fills the fractures and replaces particularly the quartz eyes in the granite (see photo, page 14). A blue amphibole was also observed replacing quartz veins. Some of the wider fractures are filled with a fine, dark, greenstone-like rock. 13 Niobium-Bearing Complexes East of Lake Superior

The fractured granite grades into a breccia consisting of variously sized and shaped fragments of granite, the above-mentioned greenstone-like rock and, locally, diabase. The matrix appears to be mostly granulated granite and pyroxene. A thin section shows the pyroxene to be sodic and introduced. In some outcrops, this rock might be mistaken, on first impression, for a basal-type conglomerate. There are several excellent outcrop areas of this breccia on the southwest and south flanks of the complex. Along the northwest side of the main peninsula, which contains the heart of this complex, there are several outcrops of a highly carbonatized fenitized granite breccia. They weather rusty red to brown. The fragments are mostly variously altered granites, although other types, including occasional fragments of foliated carbonatite, are present. (See photo, page 16, top.).

Fenetized granite with fractures filled with pyroxene, and quartz eyes partly to completely replaced by pyroxene. Some incipient brecciation is present in the centre of the picture. Seabrook Lake area.

Outcrops indicate that the width of this fenitized granite breccia zone ranges from a few to several hundred feet. Topographically depressed areas and the magnetic data indicate that the breccia zone may be more prevalent than outcrops indicate.

IJOLITE, BIOTITE PYROXENITE, AND RELATED BRECCIA A group of rocks, consisting of various proportions of pyroxene, nepheline, biotite, and sometimes feldspar, are present on, and as an elongation of, the south flank of the main carbonate-alkaline core. In composition they may be divided approximately into two types, biotite pyroxenite and ijolite, although these rocks are quite variable in composition and gross features, even in the same outcrop. The biotite pyroxenite, besides biotite and pyroxene, normally contains some fine interstitial nepheline. The ijolite consists of varying but generally nearly 14 Geological Report No. 3

Two photographs of fenitized granite breccia that show the greenstone-like streaks partly to com pletely brecciated into fragments. The matrix in both photographs is darker than the granite fragments due to pyroxenitization. Seabrook Lake area.

15 Niobium-Bearing Complexes East of Lake Superior

Fragment of foliated carbonatite in highly altered breccia. Seabrook Lake area.

An ijolitized breccia with biotite-pyroxenc-rich fragments in a lighter-coloured nepheline-rich matrix. The field evidence suggests that this type is a nephelenized, biotitized, pyroxenitized granite breccia. Seabrook Lake area.

16 Geological Report No. 3

The left-hand part of the photograph shows ijolite with irregular nepheline stringers and blotches; the upper part shows a semi-foliated biotite pyroxenite with one nepheline-bearing "band" visible. Seabrook Lake area.

A medium-grained ijolite; the light mineral is nepheline, and the dark mineral is mostly pyroxene. Seabrook Lake area.

17 Niobium-Bearing Complexes East of Lake Superior equal amounts of nepheline and pyroxene. Although these rocks are generally medium-grained, occasionally the pyroxene crystals are coarse. The nepheline ranges from minute interstitial grains to rather coarse euhedral phenocrysts. There are some good exposures of a quite attractive ijolite with abundant rec tangular nepheline phenocrysts. "Fragments" are numerous in some outcrops, and relic-type "fragments" in most outcrops. They are generally of the type rich in pyroxene and biotite, although nepheline-rich types are also present (see photo, page 16, bottom). Some outcrops show a type of foliation often due to narrow strings of nepheline crystals or narrow zones richer in nepheline (see photo, page 17, top). Some outcrops are cut by a mesh of nepheline stringers. A distinct contact may be present between the biotite pyroxenite and ijolite, but neither type shows any chilling or change of texture at these contacts (see photo, page 17, top). A narrow, dark, meandering dike with coarse feldspathoid phenocrysts strung along its centre was found cutting both types. The transition from pyroxenitized granite breccia to ijolite, in two areas, where exposed, occurs over a few feet. A feldspar-pyroxene facies exists between them, with relict fragments. No ijolite dikes were found cutting other rocks in the area. In both the Lackner and Nemegosenda alkaline complexes there are exposed excellent examples of similar ijolitic rocks that have been created by the replace ment of fractured and brecciated pre-existing rocks. From this fact and the evidence given here, it is considered that these rocks are predominantly metaso matic in origin. MAFIC BRECCIAS In the central core area there is a heterogenous group of rocks grading inward from the carbonatized granite breccia. Mineralogically they are characterized by the presence of carbonate, biotite, pyroxene, and secondary minerals, and by the absence of feldspar and nepheline. The proportions of these constituent minerals vary greatly. Other minerals noted were magnetite, sulphides, fluorite, chlorites, and dull earthy mineral mixtures. The outcrops are often deeply weathered, and display a fragmental texture; this brecciated or fragmental character is not always readily discernible on freshly broken surfaces. Dark biotite-rich soils are common to areas underlain by these rocks. These rocks are almost always cut by many foliated carbonatite dikes. However, one outcrop of this breccia had a conspicuous content of small white, angular, carbonate fragments, some of which were definitely foliated. No evi dence of in situ brecciation of the foliated carbonatite dikes was noted. Possibly some of these breccias are of an injected type; on the other hand, there is ample evidence that some of them are more highly altered granite breccias, or biotitized and carbonatized ijolites. In mapping, a line between the granite breccias and these breccias was drawn wrhere the granite fragments were no longer recognizable. Magnetically, these rocks are represented by a distinct anomalous area surrounding the magnetically weak central core.

CARBONATITES These are distinctly foliated rocks consisting chiefly of calcite. The foliation is accentuated by a minor content of such minerals as pyroxene, amphibole, mag netite, chlorite, and a red, earthy mineral mixture. The foliation indicates that these dikes are essentially ring-like structures.

18 Geological Report No. 3

There are excellent examples of these rocks cutting fenitized granites imme diately south of the southwest bay, and also along the east shore of the main peninsula on Seabrook Lake. An apparent dike occurs on the west shore of the lake, about 3,000 feet north of the main alkaline core in an area where only granite and diabase are exposed. There are zones of coarse calcite crystals in this dike and, although the contacts are not exposed, the evidence indicates both walls to be rich in biotite; this dike is about 35 feet wide. Dikes of these foliated carbonates are most abundant in the area of the mafic breccia. They also appear to increase in number as the centre of the area is approached. Only two outcrops exist in the magnetically weak core, and these are both carbonates. This evidence is taken to indicate that the topographically low area in the core is underlain by carbonate rocks.

Inclusions of red fenitized granite in a foliated carbonatite that is cutting fenitized granite. Seabrook Lake area.

The contacts of these carbonate dikes are quite sharp, with no signs of chilling or of an increased amount of carbonate replacement in contacting rocks adjacent to them. Along some contacts there is some evidence of spalling off of thin layers of the rock wall.

MISCELLANEOUS ROCKS In the western part of the main peninsula there is an area of highly decom posed red rocks, which are relatively rich in red earthy hematite. There is evidence of fragments and partly hematized carbonate dikes. It is quite possible that these rocks are surficially altered mafic breccias and carbonatite dikes. On the west shore, north of the main alkaline rock peninsula, there are two outcrops of a uniform, medium-grained rock consisting of about equal proportions of brown biotite and a light-green silicate. These exposures occur in an area of granite, fenitized granite, and diabase, and appear to be part of a dike-like mass. 19 Niobium-Bearing Complexes East of Lake Superior

ALKALINE DIKES There are a number of small occurrences of what appear to be late lampro- phyre-type dikes; one was noted cutting granite breccia on the extreme south flank, and another cutting mafic breccia, on the north flank. A lamprophyre dike, with numerous pebbles of granite and altered granite, occurs several miles from Seabrook Lake along the road from the lake to the main highway.

Structure The general distribution of the rocks, the magnetic data, and the average trends of the foliated carbonate dikes indicate that the centre of the area is a circular pipe-like body. Although there is ample evidence of in situ brecciation along the borders of the complex, it is also probable, as some evidence suggests, that there are breccias present of injected types. A late fault running through the heart of the complex is indicated by a topographical lineament, by an interruption in the magnetic trends, and by an offsetting of the rock formations.

Mineralization There are showings of fluorite, magnetite, hematite, and pyrochlore, with an unidentified radioactive mineral accompanying pyrochlore, but these minerals have not so far been located in sufficient quantities to constitute an orebody. As in the other areas described in this report, the carbonate and alkaline rocks here all contain niobium. A sample of typical ijolite assayed 0.03 percent Nb205. Assays of samples of mafic breccia and calcite carbonatites range from 0.01 to 0.33 percent Nb20s. This last assay was from a carbonatite dike in fenitized granite at location B on the accompanying map (No. 2005, map case). The best niobium assays obtained so far (over l percent Nb2O6) have been taken from a small magnetite-rich zone in foliated carbonates on the north-east corner of the main peninsula, and marked as Location A on the accompanying map. The Provincial Assay Office of the Ontario Department of Mines made a study of material from Location A. Minute, honey-yellow, octahedral crystals were separated and identified by X-ray methods as non-metamict pyrochlore. A spectrographic analysis of clean magnetite crystals showed titanium 1-10 per cent, and niobium 0.5-5.0 percent in addition to iron. A sample of magnetite when heated and X-rayed gave a clear ilmenite pattern, but no clue as to the form in which the niobium occurs. The hematite mineralization is exposed in an area about 300 feet square. Although it may underlie a larger area, its iron content, as revealed in exposures, is not sufficient to make ore. In 1958 the only claims in the area were eleven held by W. Bussineau; these cover part of the carbonate-alkaline complex.

MAGNETIC DATA AND RADIOACTIVITY

Magnetic Data A condensed presentation of the ground magnetic data is given in the accompanying figure. This is compiled from a survey by G. W. Sander for 20 Geological Report No. 3

Magnetic contours in thousands of gammas

Linear magnetic trends

Ground magnetic map of the Seabrook Lake complex, after a survey by Tarbutt Mines Limited. 21 Niobium-Bearing Complexes East of Lake Superior

Tarbutt Mines Limited submitted for assessment work to the Ontario Depart ment of Mines. 1 Some of the more salient features of these data are: 1) The magnetic aureole around the central core and its offset by a north- south-trending fault. This aureole corresponds to the area underlain by the rocks called mafic breccia. 2) The magnetic anomaly extending south from this central area. It is underlain by ijolites and pyroxenites, although these rocks are not all magnetic. 3) The numerous northwesterly trending magnetic anomalies in the granite area and their disappearance as the carbonate-alkaline complex is approached ; all the outcrops found on these trends are diabase dikes.

Radioactivity Radioactivity is weak over most of the area. The highest values encountered were about ten times background. Although the pyrochlore areas are radioactive, the best assays for niobium do not correspond with the highest radioactive readings.

KJnt. Dept. Mines, File No. 63.799.

22 CHAPTER III Firesand River Area

INTRODUCTION

General The Firesand River carbonatite complex lies along the common boundary of Township 28 and Township 29, Range XXIII, District of Algoma. It is in the area generally referred to as the Michipicoten area. It is about 4^ miles due east of the town of Wawa and is readily accessible by a branch road from the highway joining Hawk Junction and Wawa; the distance from Wawa is 9 miles by road.

Acknowledgments The author is indebted to officials of Algoma Ore Properties Limited for making available the results of their exploration work, and in particular he wishes to acknowledge the co-operation of G. S. Gilbert, exploration manager, and A. M. Goodwin, chief geologist. While in the field, R. Morrison, N. Morrison, F. Krimpotich, and W. Jarvis rendered the author many favours, which he gratefully acknowledges.

Previous Mapping and Work Done In 1927, T. L. Gledhill (1927, pp. 43, 44) in his report on the Michipicoten. Gold area described showings on the "Gibson Iron Claims;" these showings were on what is now called the Firesand River carbonatite. In 1931, E. S. Moore (1932, pp. 42, 43) noted this area of carbonates and drew attention to the fact that they are different from the siderites of theMichi- picoten-Goudreau area and resemble more ordinary limestone or dolomite. In 1951, Algoma Ore Properties Limited tested the area by diamond-drilling for iron. Niobium was first detected in the area in 1953. In 1955 this company re-examined its claims for niobium and drilled a number of additional holes.

Present Mapping In July and August 1958 the author spent seventeen days in the area on behalf of the Ontario Department of Mines. This time was spent examining the Algoma Ore Properties© core, and mapping the calcite carbonatite outcrops and the outlying claims beyond those shown on the existing maps of the company. Recent claim survey plans were used for control in compiling the geological map (No. 2006, map case). Considerable time was spent tying in the many streams, beaver ponds, lakes, and the old base and picket lines. Nearly all the geology of the central dolomite core was taken from Algoma Ore Properties© maps. Dense underbrush over much of the outcrop area made mapping difficult, and very close traversing would have been necessary to include all the exposures; this would have taken up more time than could be allotted to the project. 23 Niobium-Bearing Complexes East of Lake Superior

Topography The core of the area is an oval-shaped hill rising about 150-200 feet above the surrounding terrain. The area east of the hill consists largely of a flat sand plain. The areas to the north, west, and south are dissected by many sharp draws and valleys. Although most of these depressions trend in a northeasterly direction, some trending north-south and east-west are also present. Streams, beaver dams, and long narrow lakes are common features of the northeasterly-trending valleys. Although outcrops are generally scarce, rubble areas are fairly common; pits indicate that overburden is light over much of the area except in the sand plain.

GENERAL GEOLOGY

The geology of the Michipicoten area, in which the Firesand complex occurs, has been described as a typical Precambrian Keewatin-Algoman geological province. The Keewatin formations consist of acid to basic lavas, tuffs, and banded iron formation. The Algoman intrusives range from granite to syenite, with porphyry and lamprophyre dikes. These rocks are all cut by diabase dikes classed as Keweenawan in age. In the past, there has been a small amount of gold produced from a number of mines in the area. At present, Algoma Ore Properties has two producing siderite mines, the Helen and Sir James mines; these are 3^ miles northwest and 3 miles north, respectively, of the centre of the area described in this chapter. The Firesand complex is about 1^ square miles in area, and aeromagnetic data indicate it to be uniquely circular and isolated in character. It consists predominantly of carbonate rocks a dolomitic core surrounded by calcite carbonatite rings interzoned with a mafic carbonate and silicate rocks, and green stone. These interzoned rocks may actually be more crescent-shaped, inclusion- type masses, than rings maintaining a constant width completely around the core. Rocks with feldspar or feldspathoids as a significant constituent represent a very small part of the total mass.

TABLE OF FORMATIONS PRECAMBRIAN CARBONATE AND ALKALINE ROCKS: Basic dikes. Dolomitic core rocks. Calcite carbonatite. Mafic carbonate and silicate rocks. COUNTRY ROCKS: Matachewan(?) diabase. Algoman granites and syenites. Keewatin greenstones.

Description and Distribution of Rock Types

COUNTRY ROCKS From the evidence of surface outcrops, the chief rock types along the west and northwest flanks of the carbonatite area are Keewatin-type greenstones. These are mostly a dark-green, dense andesitic or basaltic type. On the north side, there is also some evidence of the presence of dacites or quartz-bearing

24 Geological Report No. 3 syenitic rocks, or both. Drill holes penetrating towards the east flank indicate from inclusions in the carbonatite that the country rock here is greenstone. Outcrops along the southwest flank indicate that the chief rock type here is a rock ranging from a quartz-bearing syenite to granite. A few outcrops of green stone and one of diabase indicate that these two types are present on the south flank.

ALTERATION OF COUNTRY ROCKS In outcrops there is very little macroscopic evidence of alteration of the country rocks. However, all the contacts exposed on surface are with narrow carbonatite dikes, and none are with the main carbonatite masses. The only noticeable effects in these surface exposures are local ribbing along numerous intersecting fractures, and a deeper green-black weathering of the greenstones. There is no evidence of a rusty carbonate-type of alteration. In drill core, the amount of alteration of the greenstone is highly variable. Narrow fractures filled with biotite or a green pyroxene, or both, are common. Fragments of greenstone with black biotite selvages are common to some of the carbonatites. Uniformly developed small black biotite porphyroblast^ are a frequently occurring feature in some of the greenstones adjacent to carbonatites. A thin section of greenstone from diamond-drill hole No. 18 (Algoma Ore Properties) revealed a fine-grained mosaic of fresh, bright-green pyroxene in a matrix mainly composed of feldspar. This was cut by intersecting fractures filled with coarser pyroxene and calcite. The central area between some of the fractures showed a strong development of small books of brown biotite. It is highly probable that further petrographic work would indicate that the green stones are more highly pyroxenitized than is evident in hand specimen. With such a large volume of injected carbonates in the area, strong carbonatization of the country rocks would be expected. The biotite-calcite rocks, occurring as masses in the carbonatite and described in the next section, are possibly the result of carbonate metasomatism. An interesting point is that this carbonate metasomatism is preceded by pyroxenitization of the greenstones, and that the contact between these two types of metasomatism occurs over a few inches.

MAFIC CARBONATE AND SILICATE ROCKS Under this heading is a group of fairly mafic and closely associated rock types. They occur chiefly as zones intermixed with the calcite carbonatite and fenitized greenstone. The most abundant type is a fine-grained, dark biotite-calcite rock with or without pyroxene. The mafic minerals generally exceed the calcite content. Some varieties of this type are distinctly replaced pyroxenitized greenstone. On the other hand, a variety occurring in dike-like masses resembles an intrusive rock. A very distinctive type, which has been called a mafic silicate rock on the geological map (Map No. 2006, map case), consists of varying proportions of biotite, pyroxene, nepheline, black garnet, unidentified light-coloured silicates, apatite, and calcite. The biotite replaces the pyroxene, and the garnet often has inclusions, among which is nepheline. Some of the calcite partly replaces nephe line. This rock type ranges from fine to coarse-grained, with the medium-grained varieties more prevalent. Some of the dike-like masses have finer-grained borders and replace greenstone. Calcite is generally more prevalent in the centre of these "dikes" and sometimes becomes abundant enough for the rock to be called a carbonatite. A number of these "dikes" are exposed, cutting greenstone 25 Niobium-Bearing Complexes East of Lake Superior on the west flank, and in one exposure this type forms a zone along one wall of a calcite carbonatite dike. Some core specimens of this type are identical to specimens from the Hebden (Portage) Lake section of the Lackner area. They also show some marked similarity to zones and dike-like masses of greenish-black garnets, nepheline, orthoclase, apatite, and aegiritic augite cutting the foliated rocks in the fire tower section of the Lackner area. Some of these zones in this part of the Lackner area also have foliated calcite carbonatite centres. The evidence indicates that this group of rocks, referred to as mafic carbonate and silicate types, are essentially metasomatized greenstones and other country rocks, the end phase of which is a biotite-calcite type. In some cases an inter mediate ijolitic phase is indicated.

CALCITE CARBONATITE Outcrops, rubble areas, and diamond-drill holes indicate that this rock is the dominant type, in widths up to 2,000 feet, in the area immediately surrounding the topographically high, dolomitic core. The calcite carbonatite is interzoned with the mafic and country rocks previously described. Either a number of calcite carbonatite rings are present in this zone, or else these interzoned rocks are inclusions in a single ring. In the greenstones on the northwest flank, there are a number of exposures of this calcite carbonatite rock indicating additional ring-like structures. One of these exposures is shown in the photograph on the opposite page. The foliation in these rocks tends to surround the central dolomitic core and dips steeply inwards. This calcite carbonatite is a very distinctive rock consisting usually of rather coarse calcite with varying amounts of biotite, apatite, magnetite, pyrrhotite, aegirite, pyrochlore and, locally, actinolite. The total of these minerals generally averages about 15 percent, although they may be abundant over short widths. The magnetite is present in some areas in a sufficient quantity to create magnetic anomalies. It occurs as small, perfect-to-rounded and distorted octahedra. Immediately south of the main dolomite hill there are some outcrops of a rather distinctive rock. This rock consists of coarse, white calcite rhombs in a medium- to light-brown-weathering carbonate, and is marked as porphyritic carbonatite on the map. A chemical analysis of this type is given in the table on page 6. Normally, exposures of these rocks are completely disintegrated to a granular mass.

DOLOMITIC CORE ROCK This rock occupies the central part of the area, which stands up as a distinct hill. In outcrops it weathers a deep rusty brown, indicating its ferruginous nature. Locally, massive hematite has developed in it as a surficial-type deposit. Foliation is faint or absent. The unweathered rock is best seen in drill core. It is fine-to-medium grained. The mafic content ranges from minor to major amounts, and consists chiefly of chlorites and unidentified secondary minerals. None of the fresh primary mafic minerals common to the calcite carbonatite, such as aegirite, biotite, apatite, and magnetite, were noted in this rock. In some of the drill holes, quartz and brecciated quartz mineralization is common. Barite is also reported in surface trenches but was not specifically noted by the author. There is evidence that this dolomitic core may be the calcite carbonatite and mafic rocks, previously described, which have been dolomitized and altered. 26 Geological Report No. 3

BASIC DIKES In the Algoma Ore Properties© drill core there is evidence of dikes, a few feet wide, composed of dark-grey, fine-grained basic rocks with chilled contacts. A few were noted cutting greenstone in outcrops in the Morrison claims. The distinctive biotite and olivine lamprophyre dikes, described by Gledhill (1927, pp. 14-17) and Frohberg (1937, p. 39) in the gold area a few miles to the southwest of the Firesand complex, are possibly related to it in origin. Their mineral assemblage certainly suggests a similarity to that encountered in late dikes occurring with these carbonate-alkaline complexes. The minerals reported in these dikes are olivine, biotite, augite, apatite, magnetite, rutile, carbonates, serpentine, and chlorite.

Foliated carbonatite dike (on the right) cutting greenstones (on the left) on a stream northeast of Claim S.S.M.21668. Firesand River area.

Structure Aeromagnetic data indicate that this carbonatite complex is a remarkably circular structure. Both the distribution and foliation of alkaline and carbonate rocks conform with this type of structure; however, there is insufficient evidence to prove or define it in detail. Foliation in the calcite carbonatite indicates that the rocks in the complex dip steeply inward. There is some evidence of radiating structures being present in the form of narrow carbonate dikes and veins. Topographical features indicate many faults and joints of a regional type traversing the area. Two trends are particularly pronounced, in north-south and northeast directions. A left-hand displacement is common for north-south striking faults north of this carbonatite area. Although this is suggested in the case of one fault, there is insufficient information on this carbonatite to state that this is the common direction of displacement. 27 Niobium-Bearing Complexes East of Lake Superior

MAGNETIC DATA AND RADIOACTIVITY No ground magnetic surveys have been made over the complex. However, Algoma Ore Properties covered the area with one of its airborne surveys, and they have kindly permitted the publication of the results (see figure below).

Aeromagnetic sketch map, Fircsand River complex.

The unique, isolated and circular character of the anomaly is indeed striking. The dolomite core is represented by a central magnetic low, and the area under lain by the magnetite-bearing calcite carbonatite rings is represented by an encircling magnetic high. The two lobes in the south contact are probably due to diabase dikes. 28 Geological Report No. 3

The similarity of this magnetic pattern to that common to small intrusive syenite stock bosses is outstanding. Radioactivity is slight over most of the area. Several times background is generally the highest reading that can be obtained. The radioactivity over the best showing of rather coarse pyrochlore mineralization on the Morrison claims is almost non-detectable. There are a number of very radioactive carbonate- thorium-bearing showings, both to the north and southwest of this carbonatite complex, which are possibly related to it in age.

ECONOMIC GEOLOGY

Mineralization Hematite was the first mineral in the area to attract prospectors. Work by Algoma Ore Properties, however, indicated that the high grade occurrences of this mineral are surficial in origin, and that the possibilities of outlining an orebody of this mineral are rather remote. The results of core assays made by Algoma Ore Properties indicate that niobium is present as a minor constituent in these alkaline and carbonate rocks; a few assays also indicate that it is present in the fenitized greenstones. The best and most consistent content is found in the calcite carbonatite. The higher- grade sections in this rock are visibly little different from the adjacent lower- grade material; possibly magnetite crystals are more prevalent in the higher- grade sections. Some of the better-grade sections are in the carbonatite adjacent to the other rocks, indicating a contact association. Pyrochlore is the only mineral that has been visually noted and identified. A study was made, by the Provincial Assay Office, on pyrochlore-bearing calcite carbonatite from the Morrison showing at location B shown on the geological map (No. 2006, map case); this showed the pyrochlore to be only partly metamict, giving a good X-ray pattern without heating. The results of a spectrographic analysis of this pyrochlore are listed below. PERCENTAGE Over 10...... Nb 5-15...... Ca 1-10...... Zr, Ti 0.5-5.0...... Th, Ce, Na 0.1-1.0...... La, Fe 0.05-0.5..:...... Y Not detected...... Ta, U A study of the magnetite revealed that it contained both titanium (5-15 percent) and niobium (0.05-0.5 percent). An X-ray pattern of this magnetite revealed ilmenite but no niobium mineral.

Description of Properties

ALGOMA ORE PROPERTIES LIMITED

Algoma Ore Properties Limited is a wholly owned subsidiary of Algoma Steel Corporation. In 1958 they held 33 surveyed claims and 5 unsurveyed claims, covering the central and major part of this carbonatite structure. They have completed a geological survey, a dip-needle survey covering part of the claim group, and twenty-two diamond-drill holes. In addition, several short holes have 29 Niobium-Bearing Complexes East of Lake Superior been drilled by small portable diamond-drills. The first work was done to explore iron possibilities, but more recent exploration has concentrated on testing the niobium content. Surface sampling gave results of up to 0.52 percent Nb2O6 in calcite carbona tite outcrops and rubble areas. At Location C on the geological map, small, well- formed, light-brown octahedra of pyrochlore occur in a disintegrated calcite carbonatite exposure, with magnetite crystals of similar size and shape, and apatite and biotite. Surface sampling of the dolomitic core area by Algoma Ore Properties re vealed only very low niobium content, except at Location D. Here, assays up to 1.32 percent Nb2O6 have been obtained in a very rusty outcrop. Of the 22 holes drilled, 13 were drilled in the more favourable calcite car bonatite zone. These were holes Nos. 10-22, totalling slightly over 7,700 feet. The niobium content in the core ranged from a trace to 0.62 percent Nb2O5 ; the latter assay was in hole No. 11 between 450 and 460 feet. Some of the other sections giving niobium assays are as follows:

Nb,O 6 Extent Hole No. Footage percent feet 0.30.. . . . 50 11 780-830 0.24.. . . . 53 18 17-70 0.25.. . . . 30 19 160-190 0.25...... 140 20 540-680

Holes Nos. 11, 18, 19, and 20 are shown on the geological map (No. 2006, map case).

MORRISON ET AL CLAIMS

Pyrochlore showing in foliated carbonatite on the Morrison et al claims at Location B on the geological map (No. 2006). Firesand River area.

30 o o o CN l Q. O

O) O

O)

•o o

X Q. Niobium-Bearing Complexes East of Lake Superior

Nine claims on the northwest flank were held jointly by N. and R. Morrison, F. Krimpotich, and W. Jarvis of Wawa. Their work consisted of prospecting and trenching, which has increased the amount of carbonatite exposed and disclosed showings with visible pyrochlore. The two main showings are marked as locations A and B on the geological map. (Map No. 2006, map case). The showing at Location A occurs in a trench on the east side of a hill, 300 feet east and 100 feet north of No. 4 post of surveyed claim S.S.M. 21664. Here, typical, crumbly calcite carbonatite is exposed across a 20-foot width. Assays of up to 0.29 percent Nb2O5 have been obtained across this width. Small amber- coloured octahedra of pyrochlore are visible in a more solid rib of carbonates. The showing at Location B occurs in a creek bed, 1,100 feet S.81 0W. of the No. 4 post of surveyed claim S.S.M. 21685. It has been well exposed by a recent wash-out along the creek. The geology is shown in the accompanying figure. Here, pyrochlore crystals up to /4-inch across, with magnetite crystals up to /4 inch in diameter, and rosettes of actinolite, are particularly plentiful along the northwest side of the exposure. The exposed width of this calcite carbonatite is 15 feet, and its southeast contact with the greenstones is not exposed. In view of the size and uneven distribution of the pyrochlore, close drilling or bulk sampling would be required to obtain a reliable estimate of the niobium content. Pyrochlore-bearing carbonatite boulders are plentiful for 300 feet upstream and 200 feet downstream along the general strike of the zone.

32 CHAPTER IV Nemegosenda Lake Area INTRODUCTION

General The Nemegosenda alkaline complex is about nine square miles in area. It lies in the northwestern part of Chewett and the adjoining townships of McGee, Pattinson, and Collins. It is generally centred on Nemegosenda Lake, which is 16 miles northeast of the town of Chapleau. Chapleau is a railway and lumbering town on the main transcontinental Canadian Pacific railway line, 170 miles northwest of the city of Sudbury. 1

Acknowledgments The author is indebted to R. D. Wyckoff, vice-president of Dominion Gulf Company, for making available all the information assembled by that company in their exploration of the area. He is also indebted to A. K. Temple, formerly of Dominion Gulf Company, for the privilege of incorporating in this report petro graphic data from a paper he prepared for publication in 1957 entitled "The Petrology of the Nemegosenda Alkaline Complex, Ontario."

Previous Mapping and Work Done As mentioned in the introductory paragraphs in Chapter I of this report, Bell of the Geological Survey of Canada gave the first and only recorded descrip tion of the rocks at Trout (Nemegosenda) Lake, on a map dated 1883. There was no evidence of staking or prospecting in the area prior to Dominion Gulf Company©s entry in 1955. This is the only company that has done any work in the area, and this work is reviewed in the descriptions of properties. The author was closely associated with all this work.

Present Mapping The mapping for this chapter of the report consisted of ten days© field work, which was concentrated on mapping of ground not previously mapped by Dominion Gulf Company. This chapter is largely a compilation of data collected by that company.

Topography There is no prominent topographical expression of the circular Nemegosenda alkaline complex. However, the west shore of the lake, and also ridges of gneiss along the east, northeast, and south flanks, are sufficiently arced to suggest a circular structure. The area underlain by the alkaline rocks is topographically depressed, but due to glacial fill, this is not particularly obvious.

rrhe Foleyet-Chapleau highway to be completed in 1961 will pass 3 miles south of the area. 33 Niobium-Bearing Complexes East of Lake Superior

East of the lake the terrain is mostly a plateau, 150 feet above the lake; this changes to rock ridges and glacial hills as the rim of the complex is reached. To the south, west, and north of the lake, the topography ranges from highly dis sected plateau to rock ridges and sand and gravel hills. Outcrops over the alkaline area are few and widely scattered. They are mostly found along the lake shore or near the rim of the complex. Boulders of alkaline rocks are locally abundant over the complex and are liberally scattered for several miles to the south. Diamond-drilling indicates, locally at least, that the rock surface is highly erratic, and that some deep sand-and gravel-filled gorges exist.

GENERAL GEOLOGY The Nemegosenda complex is approximately circular and 3-4 miles in diameter. It consists predominantly of alkaline silicate rocks, and occurs in a region dominated by gneisses. There is no evidence of other intrusive masses in the surrounding area except similar carbonate-alkaline complexes, possibly some gabbro, and diabase dikes. A general idea of the geology of the alkaline area as a whole can be obtained from the scattered outcrops, the ground magnetic data, and diamond-drilling. Detailed information is only available for parts of the north and east flanks where the diamond-drilling has been concentrated. The alkaline complex may be divided into two main units, the syenite core and the metasomatic aureole. The syenite core, which is about 3 miles in diameter, is composed of a number of rather distinct types. These rock types are predominantly leucocratic and differ in texture and in their proportions of alkali feldspars, nepheline, biotite, and soda pyroxene and amphibole. The rocks of the so-called metasomatic aureole may be divided into three general zones; from the syenite core outwards, these zones are: syenide contact zone, pyroxenide zone, and red alkaline fenite zone. The red alkaline fenites are among the oldest rocks present. So far, they have been found on the north and adjoining parts of the west and east flanks adjacent to the fenitic (metasomatically altered) gneisses. They mark a zone of hydration and oxidation. The pyroxenide zone represents a zone of dehydration and reduction, with the development of crystalline pyroxene-rich rocks. This pyroxene is either superimposed on the red alkaline fenites, or with orthoclase, forms a rheomorphic type occupying openings in, or replacing, fractured and brecciated fenitic rocks. This zone represents a type of "basic front." The syenide contact zone represents the transition from the fenitized rocks of the metasomatic aureole to the granitoid textured rocks of the syenite core. Towards the core, this zone shows a marked increase in alkali feldspar, biotite, and nepheline, and a marked decrease in soda pyroxene and pyrochlore. Cutting the above-mentioned rocks of the metasomatic aureole there is a wide range of rock types occupying and replacing breccia zones. These zones are chiefly composed of such minerals as magnetite, apatite, biotite, alkali feldspar, and calcite, with one or two of these minerals dominating particular parts of a breccia zone. Specific types of these rocks have been called jacupirangite, biotite-feldspar pegmatites, and sovites. All rocks are cut by carbonate veins and late mafic dikes.

34 Geological Report No. 3

TABLE OF FORMATIONS PRECAMBRIAN ALKALINE ROCKS Alkaline Intrusives: Quartz-carbonate-chlorite dikes and late carbonate veins. Late malic dikes, porphyry dikes. Alkaline syenites: pulaskite, juvite, foyaite, malignite. Igneous Contact Rocks: Syenite rocks and breccias. Intrusive, Replacement, and Rheomorphic Rocks: Malignite, malignitic breccia. Biotite-feldspar pegmatite. Jacupirangite. Sovites and sovite breccias. Fen iles: Pyroxenitic fenite. Red alkaline fenite. Ijolite, ijolitic fenite. COUNTRY ROCKS: Gneisses, gabbro, etc.

Description and Distribution of Rock Types COUNTRY ROCKS The country rocks surrounding the alkaline complex are acid to rather basic gneisses. These are cut by a small gabbro mass on the north flank, and in at least two areas by a biotite pyroxenite, which has been grouped with these rocks because its age could not be determined. The gneisses consists chiefly of bands of hornblende-oligoclase-andesine and quartz-oligoclase-biotite. Red garnets are present locally in both types and are sometimes abundant. On the northeast flank there are outcrops of a very distinctive dioritic orthogneiss now variously fenitized. They originally consisted of uniformly distributed augite phenocrysts in an andesine matrix. This type is also exposed on the southwest flank. On the extreme north flank, in Collins township, on the west side of Nemegosenda Lake, there is a coarse-grained gabbro consisting of andesine- labradorite laths, augite, olivine, and magnetite. Except where attacked by alkaline metasomatic solutions emanating from fractures, the minerals in this gabbro are quite fresh. A general parallel orientation of the feldspar and augite gives the rock a foliated fabric. This rock has sufficient magnetite to be outlined readily by magnetic surveys. ALTERATION OR FENITIZATION OF COUNTRY ROCKS The macroscopically visible features in these rocks denoting proximity to the alkaline area are a reddening of the white feldspar and the development of bright green pyroxene and blue sodic amphibole. These mafic minerals usually fill and extend from fractures. They show a preference for quartz, if that mineral is present. Briefly, petrographic studies of the alteration of the gneisses reveal destruction of quartz, the calcic-sodic feldspars, common augite, and hornblende, and their replacement by such minerals as sodic pyroxene, ferrie biotite, hydrated mineral mixtures, alkali feldspar, etc. This metasomatic alteration shows a striking similarity to that described by Von Eckermann (1948) for the Alno area, Sweden, and is covered in detail by Temple in his study of this area for Dominion Gulf Company.

35 Niobium-Bearing Complexes East of Lake Superior

FENITES Ijolite or Ijolitic Fenite Rocks consisting of nepheline, biotite, and pyroxene with minor amounts of magnetite, calcite, and apatite are exposed in a number of places in Collins town ship, west of Nemegosenda Lake. In the same locality there are also outcrops of gabbro and gneiss cut by numerous intersecting fractures, and in various stages of replacement by the above-mentioned mineral suite (photo, page 14). The nephelinization of the calcic feldspar is macroscopically quite evident. The ijolite resulting from this replacement process often shows evidence of the original fractures as well as relic fragments of gabbro and gneiss (photos, page 15).

Red Alkaline Fenite This term is used for a very distinctive, dense brick-red, radioactive, foliated to schistose rock. Macroscopically, twinned feldspar porphyroblasts and needles of bright green pyroxene are usually visible. Dark chloritic phases are common to some areas, but the indications are that this chloritization is related to altera tion associated with late faulting. Petrographic studies by Temple and others indicate this rock averages about 40 percent aegirite, 20 percent fresh feldspar, and 35 percent hydrated material, mostly after feldspar, with minor amounts of aegirite-augite, carbonates, biotite, apatite, scapolite, and fluorite. The hydrated material is a very fine grained, semi-opaque, hematite-stained mosaic. The fresh feldspars are anortho clase and orthoclase; where they both occur in the same porphyroblast, the orthoclase appears to replace the anorthoclase. These porphyroblasts often have rings of rounded aegirite crystals and occasionally some small inclusions of hydrated material. In the matrix of this fenite, small aegirite crystals are found around the edges of irregular masses of the red hydrated material. Scattered outcrops, boulder erratics, diamond-drill holes, and magnetic data indicate that this rock underlies a crescent-shaped area that reaches a maxi mum width of j?4 mile on the north flank. In outcrops, the foliation strikes parallel to the circular outline of the alkaline complex and dips steeply inward. Drilling in the Zone D area, however, indicates a considerable variation in the strike and dip. This fenite is consistently radioactive, and the niobium content is generally in excess of 0.2 percent Nb.2O5 . The fact that the unaltered gneisses contain no niobium, and the partly fenitized gneiss gives definite traces of this element, suggests that at least part of the niobium was introducted by metasomatic solutions, thus giving additional support to the view that this fenite is hydrated and alkalized gneiss.

Pyroxenitic Fenites This term is used for dark-green, pyroxene-rich rocks that are massive to highly foliated and fragmental. The generally massive and weakly foliated vari eties are uniform, fine-grained, crystalline, and with the same scattered soda- orthoclase porphyroblasts as are found in the red alkaline fenites. The matrix contains both feldspar and nepheline, hence they could be classed as ijolitic and malignitic rocks. The highly foliated and fragmental varieties occur as zones in the above- mentioned rocks and in partly pyroxenitized red alkaline fenites. The fragmental types appear to be formed largely by a ripping-apart process. The matrix is 36 Geological Report No. 3

Gabbro fractured and partly replaced by pyroxene, biotite, and nepheline. Nemegosenda Lake area.

Remnant fragments of gabbro in ijolite. Nemegosenda Lake area.

37 Niobium-Bearing Complexes East of Lake Superior

A sketch from a photomicrograph of partially pyroxenitized red alkaline fenite in the zone D area (Dominion Gulf Company); the sodic pyroxene is black, the orthoclase is white, and the hydrated material of the fenite stippled. The typical texture of the fenite is still present.

A sketch from a photomicrograph of wollastonite-bearing fenite from the East ore area (Dominion Gulf Company); the sodic pyroxene is black, the wollastonite laths are stippled, and the nepheline is clear. usually more pyroxenide and often contains such minerals as garnet, wollasto nite, and magnetite. These minerals may become quite abundant, and also develop in the adjacent non-brecciated and fragmental fenites. This mineral ization is accompanied by higher niobium content and the wollastonite-garnet mineralization both by rare-earth minerals and niobium.

38 Geological Report No. 3

On the paragenesis of the garnetiferous pyroxenide fenite, Temple notes that the aegirite-augite develops along the grain boundaries of hydrated feldspar, and is followed by the recrystallization of the hydrated material to nepheline, which later exhibits a porphyroblastic tendency. Garnet and magnetite follow nepheline, preferentially replacing pyroxene. The garnet content is inversely proportional to the pyroxene content. Temple also notes that the garnet is always spotted with magnetite. A partial chemical analysis of the garnet in dicates it is andradite (CaO, 31 percent; Fe2O3 , 30 percent). These rocks form a few isolated outcrops along the east flank, and drilling in the same area has shown them to extend across a quarter-mile width where they are the chief host rock for breccia types described below. Since they grade into the red alkaline fenites, and the evidence indicates that they are formed by the pyroxenitization, reduction, dehydration, and recrystallization of these rocks, it is supposed that the pyroxenide fenites are present, more or less con tinuously, around the complex between the red fenites and the syenite core; this supposition is supported by the magnetic data.

INTRUSIVE, REPLACEMENT, AND RHEOMORPHIC TYPES Under this heading are grouped mixed suites of rocks that are principally related to, and fill, breccia zones in the fenites. On the geological map (No. 2007, map case) they are divided into two groups: those having essentially a carbonate matrix (sovites), and those having normally a silicate matrix. The latter types have a higher niobium content than the surrounding rocks and constitute most of the potential ore zones. Silicate Rocks Malignite and Malignitic Breccia.—The known occurrences of these rocks are found chiefly in Dominion Gulf Company©s niobium-bearing Zone D, and are described later in this report under the section on that property. Jacupirangite and Biotite-Feldspar Pegmatite.—These two types appear to be closely related in mode of origin and occurrence. In fact, there is considerable evidence to suggest that they may be end, or near-end, members of a rock series. For these reasons they are described together. The term jacupirangite embraces a group of mafic rocks consisting of widely varying amounts of apatite, magnetite, pyroxene, and biotite. Pyrochlore is a consistent, minor constituent occurring in sufficient quantity to be economically interesting. The term biotite-feldspar pegmatite is used for a group of coarse-textured rocks consisting of biotite, orthoclase, and anorthoclase, with varying amounts of magnetite, pyroxene, apatite, and calcite. Minor accessory minerals are sul phides, graphite, pyrochlore, and zircon. The pyrochlore occurs as a finely disse minated replacement of fenite fragments, or as minute grains generally associated with pyroxene, magnetite, or apatite. These rocks are well developed in the East ore area, and appear to have been formed in, with or without injection into, linear breccia zones in the fenites. Fenite fragments, variously altered and replaced, are common constituents. Chilled contacts with the fenites are non existent, and books of biotite and acicular feldspar, identical to that in the zones themselves, are found as porphyroblasts in the fenite walls (see photo, page 40). The zones of these rocks strike parallel to the rim of the complex, and dip inwards. They range in width from a few feet to a few hundred feet. No outcrops occur; they are, however, the main constituent of radioactive soils found over the east flank of the complex. Niobium-Bearing Complexes East of Lake Superior

The zones of jacupirangite are quite magnetic, and the pegmatites also have sufficient magnetite to create linear magnetic zones. Carbonate Rocks Sovites and Sovitic Breccias.—The term sovite is used for a group of rocks in which the consistent and characteristic minerals are calcite and biotite, with or without pyroxene. They range in habit from true intrusive dike-like masses to replacement types in breccia zones. They have only been encountered in the east and northeast flanks where exploration by diamond-drilling has been con centrated. They correspond to rocks of similar composition in the other complex, except that the typical foliated carbonatite-types are rare. They mostly occur in lenticular-like masses in the fenites.

O.D.M.403 © -.V

Sketches of core from drill hole No. 16 of biotite-feldspar pegmatite- type rock. Natural size: white laths are feldspar; stippled areas are pyroxenitic fenite; black is mostly biotite. Upper sketch shows feldspar crystals piercing a fenite fragment; lower sketch shows porphyroblast* and irregular clots of biotite and feldspar that have developed in in fenite wallrock.

One distinctive type consists of red fenite fragments in a sovitic matrix. It is cut by dikes of another very uniformly textured sovitic type. The marginal zones of these dikes are finer-grained than their centres. Another type consists of patches of biotite and fine-grained calcite in a matrix of coarse white calcite. Apatite and pyroxene are present locally. A mass of this rock encountered in a drill hole was remarkably uniform in texture and composition. The east or lower contact was banded, and the upper contact, with a steadily increasing content of aegirite and a light mauve-coloured feldspar, graded into a malignitic rock. This type differs from all the other carbonate rocks encountered in that it contains niobium in significant amounts, especially in a zone adjacent to the upper contact.

IGNEOUS CONTACT ROCKS Syenitic Rocks and Breccias These rocks mark the transition from the metasomatic fenitic aureole to the true intrusives of the core. In the Zone D area on the north flank, there is an agglomeration of types ranging from relatively uniform syenide rocks to breccias and pseudo-breccias. Here, the fenites may be observed in various stages of recrystallization, with or 40 Geological Report No. 3

without fracturing, to syenide rocks. The uniform phases are difficult to separate from the intrusive syenite. Pseudo-breccias originate by the accentuation of the pre-existing fragmental texture of the fenites by recrystallization and replace ment, and by the direct results of feldspathization and recrystallization of the fenites away from intersecting fractures. These fractures may be filled with pyroxene and magnetite, and the unfeldspathized central area may still be essentially a fenite. Some breccia areas consist of partly to completely feld- spathized, with or without recrystallization, fenite fragments in a dark matrix of orthoclase, biotite, magnetite, and pyroxene. The diagnostic mineral changes, from the fenites to these syenide rocks, are marked development of magnetite and biotite, and also an increase in orthoclase and nepheline as the intrusive syen ide core rocks are approached. In the East ore area, drill holes have cut rocks located between pyroxenide fenites and the alkaline intrusives of the core, although the intrusives were not cut. The rocks intersected by the drill holes are predominantly leucocratic types cut by biotite-rich dikes and coarse biotite-calcite-magnetite-apatite bodies. The leucocratic types consist of a mosaic of albite crystals with interstitial cancrinite, sodalite, calcite, and biotite. These rocks may correspond to the feldspar-rich rocks noted in the Nvasaland volcanic necks.

ALKALINE INTRUSIVES Alkaline or Nepheline Syenites A group of rather distinctive nepheline syenite rocks are encountered in the central part of the area. The indications are that they occupy over half the area of the complex. There are insufficient data to define the limits of the different rock types, but a circular zonal distribution does not seem possible. The only evidence of their attitude is found immediately south of the Zone D niobium area on the north flank, where an outer expansion at depth is indicated. The syenite dikes in this area are radial in strike and vertical in dip. The southern and south western part of the igneous core is occupied by a coarse nepheline-rich syenite (juvite), and the rest of the area by medium-grained leucocratic to mesocratic rock types (pulaskite to malignitic foyaites). These syenites will be described by areas. North Flank, East Shore of Lake.—On the east shore of Nemegosenda Lake, at the common boundary of Collins and Chewett townships, along a rock bluff, and in the collar of the adit and drill holes in the same area, is a distinctive syenite called pulaskite. In composition it approaches that of a foyaite, at least locally, and the average composition may be between that of a foyaite and of a pulaskite. The rock at first glance appears to be feldspar-rich, but closer examination and thin-section study indicate that nepheline and altered nepheline may equal the feldspar content. The mafix minerals are aegirite and biotite, each ranging up to 15 percent. Two distinct textural types are present, a coarse poikilitic type and a fine to medium granitoid type; all transitional phases between these are found. The poikilitic type occurs mainly adjacent to the contacting rocks. Poikilitic orthoclase crystals up to 2 inches long and ^ inch wide are set in a darker matrix of nepheline, biotite, aegirite, and orthoclase. The granitoid type has small books of biotite evenly distributed in a fine grained matrix of pink nepheline, semi-transparent orthoclase, and aegirite. On the weathered surface it has a distinct blue cast caused by the weathering of fine grained nepheline. 41 Niobium-Bearing Complexes East of Lake Superior

The contacts between the dikes of this syenite and the intruded syenide fenites and breccias are sharp; however, the corresponding contact between the main mass of syenite and these intruded rocks is indistinct. East Shore, Concession V.— On the point on the east shore of the lake on the line between concession V and concession VI, and immediately north of it, there are reddish-brown bluffs of massive, jointed, granitoid, medium-textured syenite. Macroscopically, this rock consists of about equal proportions of mafic minerals and light-red feldspar. Nepheline is visible locally. Thin sections indicate it to be composed of 40-50 percent alkali feldspar, in part as perthitic intergrowths; 5-10 percent nepheline and altered nepheline; 20 percent biotite; 10-20 percent sodic hornblende; and minor pyroxene, apatite and magnetite. In composition it

Syenite immediately south of niobium Zone D with poikilitic orthoclase phenocrysts in a matrix of orthoclase, nepheline, aegirite, and biotite. Nemegosenda Lake area. closely resembles Lawson©s type of malignite from the Maligne River in north western Ontario, and also a type called miascite from the Ural Mountains. South from this outcrop area there are several rock bluffs along the lake shore, and isolated outcrops inland in concession V. These isolated outcrops, and boulders in the same area, are of a fresh feldspar-rich type with up to 15 percent black hornblende. The feldspars are mostly lath-shaped and are often twinned. The exposures along the shoreline are quite variable in composition and are for the most part considerably altered. Both the mafic minerals and the nepheline are variously altered to mixtures of secondary light-green minerals, so that an estimate of the average content of the original minerals is macroscopically impossible; however, they seem to range in type from intermediate to nepheline- rich syenite. South and Southwest Flanks.—A very distinctive rock called juvite is exposed on the two islands in the lake, also on the point on the east shore in the centre of concession IV, and was encountered in holes drilled in the vicinity of this point.

42 Geological Report No. 3

In addition, boulder erratics are scattered along the west shore of the lake, in concessions IV and V, McGee township, as well as in the glacial terrain for many miles to the south of the lake. This rock is a coarse-grained leucocratic type consisting of about equal amounts of nepheline and alkali feldspar. The nepheline occurs both as euhedral and anhedral crystals, and is variously altered to such minerals as carbonates, cancrinite, sericite, and hematite. This alteration causes the colours of the nepheline to range from grey, to light-green, yellow, and to red. Biotite, zircon, and apatite are minor accessories.

MISCELLANEOUS ROCKS

Late Mafic and Porphyry Dikes A number of feldspar porphyry dikes have been encountered in diamond-drill holes in the east flank. Macroscopically they are quite fresh-looking, have feld spar phenocrysts, and cut all other rocks; they resemble dikes that might accompany a normal syenite intrusive. In addition, mesocratic to melanocratic dikes are frequently encountered cutting both the country rocks and the alkaline rocks. No attempt has been made to classify them; they resemble the types found with the other complexes. Biotite-rich types are the most common. One variety is rich in serpentine, some of which is in the form of chrysotile veinlets. Most of them have carbonates and apatite as an accessory constituent, and the dikes contain little if any niobium.

Late Carbonate-Quartz-Chlorite Dikes and Carbonate Veins Very distinctive, dike-like, medium-grained rocks consisting of calcite rhombs in a chlorite with or without a quartz matrix are common to the entire area tested by diamond-drilling. Occasionally they are extensively replaced by graphite, and often contain pyrite, galena, and sphalerite, but no niobium. The evidence indicates that they accompanied late faulting, and possibly are mostly fault- fillings or in gash and other tension fractures off faults. The rocks in the vicinity are generally highly altered, being mostly chloritized and reddened. The contacts of these dikes are always sharp and are sometimes fine-grained. Calcite veins and stringers are found cutting most of the rock types, and are undoubtedly of several generations. Certain types that appear to be late in the alkaline process tend to bleach the dark-green pyroxene, eventually destroying it with the other alkaline minerals.

Structure Aeromagnetic data indicate that the general regional trend of the gneissic country rocks is northeasterly. In the vicinity of the alkaline area, the strike of these rocks tends to parellel the rim of the complex, and the rocks dip inward; however, the same gneiss bands do not circle the area. Insufficient mapping has been done to decipher the change in structure from the regional trend to the local trends. The distinctive dioritic orthogneiss exposed around the northeast flank adjacent to the alkaline rocks does not occur on the south flank; however, it re-appears on the southern part of the west flank, striking at right angles to the rim of the complex. This suggests that this rock once crossed the area now occupied by alkaline rocks. 43 Niobium-Bearing Complexes East of Lake Superior

Foliation in the fenitized rocks encircles the intrusive core and dips steeply inward. Breccia zones with varying types of mineralization such as the jacu- pirangites, biotite-feldspar pegmatites, and the sovitic rocks, are also found along linear zones or masses elongated parallel to the circular outline of the complex. There is also some evidence of ring-like magnetic zones in the intrusive core. One drill hole indicates that these are due to magnetite in fractured and brecciated zones. The only available evidence of the attitude of intrusive core rocks is in the Zone D area on the north flank, where an outward dip is indicated by diamond- drilling. The magnetic data indicate several faults cutting and shifting, in particular the rocks of the metasomatic aureole. Generally the magnetic strength and pattern are distinctly different across these magnetic interruptions, possibly indicating considerable vertical movement with a change of rock types. The underground \vork on Zone D has shown that faulting is very prevalent in this area; this is discussed later in this chapter in the section on mineralization.

MAGNETIC DATA Dominion Gulf Company©s aeromagnetic survey in the fall of 1954 disclosed an independent circular anomalous area, which is now known to be underlain by the alkaline rocks. The maximum magnetic strength recorded, above that for the immediate area, was only 1,000 gammas. The flight elevation for the survey was l,000 feet. The ground magnetic data proved exceptionally valuable in the company©s exploration program. In the early stages, these data, together \vith the evidence from boulder erratics and spare outcrops, made it possible to build up a geological picture and to define the best areas for testing by diamond-drilling. Later, magnetic data gave valuable clues to the trends of the higher grade niobium- bearing zones in the East ore area. The anomalies as detailed by a ground magnetic survey fall into several groups, and the following pattern of types is indicated by exploration so far: 1) The anomalies in the syenitic contact zone usually tend to be strong iso lated "islands," and their niobium content low and erratic. 2) The anomalies in the pyroxenide fenite zone tend to be distinctly linear and locally quite strong. They invariably contain a significant nio bium content, although there is no direct relationship between the magnetic intensity and the amount of niobium. These anomalies are due to zones of magnetite with garnet replacing the fenites, dike-like zones of biotite-orthoclase pegmatite rock, or jacupirangite. 3) The lens-like anomalies in the red alkaline fenite zone are due to sovitic breccia and are very low in niobium content. The magnetic intensity is weak over Zone D, which is the major potential ore zone, but strong anomalous conditions in the syenitic contact rocks to the south indicate considerable action. The weak magnetic conditions over the zone itself are due in part to the flat-lying attitude of the main masses of pyroxenitic rocks, and in part to the lack of much magnetite. Some comment on the relationship between geochemical and geophysical data may be useful. From the similar ionic radii of iron (0.67) and niobium (0.69), a geochemical affinity might be expected between the minerals of these 44 Geological Report No. 3 elements. This is well exhibited in the Nemegosenda area in the close association of pyrochlore with magnetite and sodic-iron pyroxenes. This association is best developed in the pyroxenide zone. On the other hand, the magnetite may exist apparently under higher temperature conditions than pyrochlore, and also in sufficient quantity to create anomalous conditions in the syenitic contact rocks. Although pyrochlore may be present in these anomalies, the over-all content is generally low. However, pyrochlore exists in volume farther removed from the intrusive core, in the red alkaline fenite zone where magnetite is absent, and the iron is in the form of hematite dust, etc. The aeromagnetic and detailed ground magnetic data have been published elsewhere (C.I.M., 1957, pp. 184-95).

RADIOACTIVITY Early in the Dominion Gulf Company©s exploration, it became apparent that there was a marked correlation between the relative amounts of radioactivity and niobium. An exception to this occurred when abnormally high radioactivity was associated with such calcic silicate minerals as green garnet and wollastonite, and the calcium phosphate mineral apatite. In these cases, it was found that in addition to the niobium mineral pyrochlore, thorium-bearing rare-earth minerals were present. Using a Canadian Aviation Electronic scintillometer placed on the rock, a reading of 250 counts per second indicated that the rock could be expected to assay about 0.25 percent Nb2O6. The niobium content was generally found to increase in direct proportion to the increase in radioactivity. Invariably, radio activity of several thousand counts per second, especially if associated with the calcic minerals noted above, and if pyrochlore was not readily visible, was found to be due to rare-earth mineralization. Radioactive detection equipment proved an invaluable aid, not only in locat- in niobium-bearing mineralization in outcrops, boulders, soils, and drill core, but also in estimating roughly the amount of niobium present.

ECONOMIC GEOLOGY

Mineralization Pyrochlore is the only niobium mineral identified so far. It occurs as a minor constituent of all the alkaline rocks, except some of the late, mafic dikes, car bonate dikes, and veins. Most of the mineral occurs in the rocks between the alkaline intrusives and gneisses. The higher grade concentrations are found in the pyroxene-rich rocks, or in breccia zones rich in other minerals in these rocks. The pyrochlore occurs chiefly as finely disseminated, resinous yellow to brown grains. Occasionally it will rim or replace breccia fragments. The minerals most indicative of higher niobium content are acicular aegirite and aegirite-augite. Both fine magnetite and apatite, as replacement minerals along zones in the pyroxenide fenites or with jacupirangite-type mineralization, are accompanied by niobium in significant amounts. However, these same minerals have little significance as disseminations or veins in the syenitic contact rocks adjacent to the syenite core, or in the gneisses and adjacent ijolites. Wollastonite and garnet occurring in deformed zones in the pyroxenide fenites are good indicators of higher grade niobium mineralization; they are often accompanied by rare-earth minerals. 45 Niobium-Bearing Complexes East of Lake Superior

The minerals or elements present that might be of possible interest as a by product of a niobium operation, or that might be encountered in economic quan tities, are uranium, thorium, rare earths (cerium, yttrium, neodymium, and lanthanum), zirconium, apatite, and magnetite. Minerals of academic interest only are fluorite, barite, galena, sphalerite, chalcopyrite, and graphite. The potential ore zones of niobium, as outlined by Dominion Gulf Company, are reviewed in the following section, Description of Properties. The correla tion between niobium mineralization, magnetic data, and radioactivity has already been reviewed.

Description of Properties

DOMINION GULF COMPANY Late in 1954 this company completed the aeromagnetic survey that located the complex. Staking was begun in February 1955, and by the fall of that year, 196 claims had been staked; these claims were covered by detailed geological and magnetic surveys. By the fall of 1956 some 35,306 feet of diamond-drilling had been completed in 68 holes. Early in 1958 an adit was driven 580 feet to obtain a bulk sample for metallurgical extraction tests. These tests reached the pilot- plant stage in 1959. The company at present holds 2,346.6 acres of mining lands under patent, and 3,617.3 acres of water-bottom under lease, and a few unpatented claims. Following is a description of the higher grade niobium zones.

Zone D This zone straddles the common boundary of Chewett and Collins townships, immediately east of the lake. It was found by cross-sectional drilling carried out to test the contact between the syenite intrusives and the alkaline fenites. No part of the zone is exposed. A total of 19,485 feet of drilling in 35 holes has been done on and in the general area of the zone. A 580-foot adit penetrated 235 feet into the zone at approximately lake level. This work has indicated 20,000,000 tons of 0.47 percent Nb.2O5 material in a block 600 by 800 feet in size and to depths up to 600 feet. The figure on page 47 shows sections, west-east and southwest-northeast across the zone, based on information from drill holes. The zone lies between an extensive area of fenites to the north, and syenide contact rocks and the intrusive core to the south. The important ore-bearing rock is a dark-green variety called malignite. It consists of orthoclase and aegiritic augite, the latter being the predominant mineral. Calcite is invariably present, and chemical analyses indicate that it may average about 10 percent. Usually minor amounts of nepheline, magnetite, sulphides, apatite, and always pyrochlore, are present. This rock occurs: as nearly flat-lying masses up to 200 feet thick, as dikes of various widths and trends, as irregular stringers, as a matrix to brecciated fenites and feldspathized fenites, and as a replacement of fenites. The larger masses are usually fine- to medium-grained, although textural varia tions are common. Some of these textural features are: rosettes of acicular pyroxene, patches of acicular pyroxene and orthoclase, vug-like areas with pyrox ene and orthoclase growing into a carbonate centre, seams of coarser malignite traversing finer-grained material of similar composition, and relic ghost-like fragments (see figure, page 48). Some of the dikes have very coarse borders, with 46 Geological Report No. 3

Fenite; fractured, brecciated and replaced or cut by malignite

Vertical sections, Zone D of Dominion Gulf Company.

47 Niobium-Bearing Complexes East of Lake Superior

Sketches of the wall of the adit to illustrate the structure of the malignite breccia of Zone D of Dominion Gulf Company. The stippled areas are red fenite, the white areas are feldspathic alteration zones, and the shaded areas are malignite. The manner in which the coarse acicular aegiritic augite occurs is shown in the upper sketch.

48 Geological Report No. 3 acicular pyroxene projecting inwards at right angles to the walls and piercing tabular orthoclase crystals. The middle parts of these dikes are uniformly fine-grained. The niobium-bearing rock next in importance in this zone is the red alkaline fenite variously replaced or cut, or both, by thin, narrow seams of aegirite-augite. The niobium content varies more or less directly with the amount of this pyroxene present in seams or as a replacement mineral; it equals the malignite in grade in the upper limits, and fenites in the lower limits. A salmon-pink leucocratic feldspathic rock occurs as: (1) fractured and brecciated masses, with the fractures filled with malignite; (2) isolated blocks and fragments in malignite; and (3) as the contacting-altered-wallrock zone along malignite dikes. It is more prevalent in the upper and inner parts of Zone D. This rock consists chiefly of albite and anorthoclase, and replaces the red alkaline fenite. It is low in niobium content, but makes ore if sufficiently traversed by malignite-filled fractures. The niobium content is found in a uniformly disseminated resin-coloured, pyrochlore, which is readily visible with a hand lens. Chemical tests have proved that the pyrochlore is not locked in the pyroxene or feldspar crystals but is interstitial to them. Post-Ore Faulting. — Evidence of this type of faulting is very prevalent in the adit and drill core. In the first part of the adit there are a series of strong faults trending northeasterly, parallel to the sharp bluff on the east side of the lake, and cutting off Zone D on its west side. Although a right-hand movement is suspected, the extension of this zone has not yet been located by drilling. In the ore zone proper the most prevalent type of faulting strikes northwest, accompanied by solutions that chloritized the adjacent rocks and introduced carbonate over widths of tens of feet. This alteration had no effect on the niobium content except the dilution caused by the introduced carbonates. Some of these faults are shown in the figure on page 47. Origin of Zone D.— Zone D is evidently a contact phenomenon between the intrusive syenite and the red alkaline fenite. The alteration of the red alkaline fenite in this contact zone to a feldspar rock has involved, among other things, the extraction of the pyroxene and pyrochlore-forming ions; these ions accumulated in the rock called malignite. As the intrusive syenite encroached on and absorbed the feldspar rock, the pyroxene-rich and relatively pyrochlore-rich malignite phase moved outward along, and occupied, zones of weakness and openings. The zones of weakness were probably caused by the syenite intrusion understoping the fenites, or by a subsidence in the complex as a whole. The latter is common to late stages in the formation of alkaline complexes.

East Ore Area This ore area embraces a magnetic anomaly, about 4,000 feet long and 1,200 feet wide, in the south half of concession VI and the north half of concession V, lots 8 and 9, Chewett township. Interest in the area was originally stimulated by the presence of numerous radioactive boulders and soils. It has been partially tested by 7,690 feet of diamond-drilling in 19 holes. This is insufficient to outline definitely the higher-grade niobium zones but, taken with the magnetic data, does indicate the possibilities of the area. A brief description of the zones follows. It is not possible to give the true widths of the zones due to lack of data on their dips. 49 Niobium-Bearing Complexes East of Lake Superior

Zone A.— This is a distinct linear magnetic zone 3,000 feet long. It has been tested in three holes along a 300-foot length. These holes gave an average of 0.45 percent Nb206 over 116 feet of core. The zone is a pyroxenitic fenite type (locally quite fragmental) interbanded with red fenite with or without replace ment by fine magnetite and green garnets. There are narrow sections rich in apatite. Pyrochlore is locally visible as well as the rare-earth mineral, monazite. Zone B.— This is a distinct linear magnetic anomaly 400 feet west of Zone A. It has been cut by six holes along its 1,700-foot length; these gave an average of 0.43 percent Nb205 over 101 feet of core. The mineralization is similar to Zone A except that the central higher-grade shoot is normally a jacupirangite. Zone E.— This zone lies immediately west of Zone B and has only a weak magnetic expression. It has been cut by four holes, which gave 0.43 percent Nb206 over 43 feet of core. It is a typical orthoclase-biotite pegmatite zone, having an indicated westward dip of 60 degrees. Zone F.— This zone lies west of Zone E and is of a similar mineralogical type. It has been cut by three holes along a 1,500-foot length. The grade averaged 0.37 percent Nb206 over 169 feet of core. Zone G.— This zone lies west of Zone F and appears to branch off it. It has been cut in three holes along a 400-foot length and has a magnetic expression 800 feet long. The mineralization is variable, but the chief niobium-bearing rocks are magnetite-bearing pyroxenite, and brecciated pyroxenite in a matrix of biotite and apatite. CONTINENTAL WOOD PRODUCTS Continental Wood Products, a subsidiary of Canadian International Paper Company, holds under patent an extensive area to the south of Dominion Gulf Company©s holdings. Alkaline rocks are present, or indicated, in the following parcels of this land: lot 10, concession V; the north half of lots 8, 9, and 10, concession IV, Chewett township; and a strip along the west shore of Neme- gosenda Lake in concessions IV, V, and VI, McGee township. No mineral exploration has been carried out by the company. Outcrops of red alkaline fenite occur along or near the west shore of Nemegosenda Lake in concession V, McGee township. Radioactivity tests in these outcrops indicate that they contain about 0.20 percent niobium pentoxide, the normal content for that rock type. On a point on the east shore of the lake, in the north half of lot 11, concession III, there is a 4-foot-wide pegmatitic dike, which consists chiefly of coarse orthoclase and aegirite and contains abundant visible pyrochlore.

50 CHAPTER V Lackner Lake Area

INTRODUCTION The Lackner alkaline complex is the largest of those described in this report. It is slightly over 9 square miles in area, and lies along the common boundary of the townships of McNaught and Lackner, District of Sudbury. Lackner Lake marks the approximate centre of the area, which is 14 miles east of Chapleau and 13 miles south of the Nemegosenda alkaline area described in Chapter IV. The area is accessible by a road from the Canadian Pacific Railway station of Nemegos, a distance of about 7 miles. This niobium-bearing area is also referred to as the Nemegos area.

Acknowledgments The author is indebted to H. Garvie of Multi-Minerals Limited for making available all the information assembled by that company, for the use of their camps, and for the privilege of examining their drill core. Information on file at the resident geologist©s office of the Ontario Department of Mines at Kirkland Lake was particularly valuable in assembling data on the various properties, and the author gratefully acknowledges the assistance of W. S. Savage, the resident geologist. The author also acknowledges the co-operation of R. W. Hodder, who has been studying the area for the Geological Survey of Canada.

Previous Mapping and Work Done The first recorded reference to the geology of the area is by Haanel (1909, pp. 110, 111) who, early in the century, described magnetite showings and noted the occurrence of nepheline syenite. R. W. Hodder studied the complex for the Geological Survey of Canada in the summer of 1956, and his report (Hodder 1958) was the first published description of the area. In 1954, E. Neczkar (1958) mapped the Multi-Minerals section of the area, and, in 1958, published a paper on the petrology of the area. Late in the last century, mineral exploration started on magnetite veins; two claims, W.D. 275 and W.D. 276, in McNaught township, were patented to cover this mineralization. In 1949, Archie Burton and his son Martin, prospect ing for a Buffalo, N.Y., syndicate, discovered strong radioactivity on the above claims. Nemegos Uranium Corporation was formed to explore these and adjacent claims. Their development program was concentrated on developing apatite, magnetite, and uranium ore deposits. In 1951, Dominion Gulf Company covered the area with an aeromagnetic survey, and later staked and investigated anoma lies on the east flank of the structure. During 1951 niobium was detected in samples assayed by Nemegos Uranium Corporation, but the indications were not further investigated. Early in 1954 exploration by Multi-Minerals Limited under H. L. Garvie, proved the presence of extensive niobium-bearing mineralization on the claims

51 Niobium-Bearing Complexes East of Lake Superior previously held by Nemegos Uranium Corporation. This started a wave of exploration, the results of which are detailed under the various properties described. Present Mapping The field investigation for the present report involved one month©s field work. Considerable time was required to tie-in the various picket-line grids made by the companies who had done work in the area, so that a base map, incorporating their work, could be compiled. Although most of the work was on compiling, reviewing, and correlating the known data, the author has seen most of the outcrops in the area and has logged much of the core. All the outcrops shown in Lackner township and about half those shown in part of McNaught township (see map No. 2008, map case), have been mapped by the author. The remainder of the outcrop information was taken from the property maps of Multi-Minerals Limited. The author has specifically attempted to avoid unnecessary duplication of the work done by Hodder for the Geological Survey of Canada, who concentrated on the petrography and on the Multi-Minerals section of the area. Consequently the description of rock types has been restricted to generalities, with the emphasis on presenting the over-all geological and magnetic picture and the results of exploration in the area so far. It was considered desirable to include in this report a section on the Lackner Lake complex so that all the known niobium occurrences in the general area east of Lake Superior would be covered.

Topography The Lackner alkaline complex is a very distinctive topographical feature. A range of hills encircling Lackner Lake rises several hundred feet above the general surrounding Precambrian peneplain. There are several marked valleys and gulleys, sharp draws cutting through the ring of hills. In the north flank, there are two gorges with shear cliffs over 100 feet high. Although the overburden is generally indicated from drilling to be relatively light, outcrops are only plentiful locally. The east and south flanks have very little outcrop. GENERAL GEOLOGY The Lackner complex is chiefly composed of alkaline silicate rocks. The dominant features are circular-trending and inward dipping zones of mesocratic to melanocratic, foliated, alkaline silicate rocks enclosed in nepheline syenite. These nepheline syenites are predominantly coarse-grained and leucocratic, although melanocratic to mesocratic types are present. As in the other areas described, gradational contacts between rock types are prevalent, as well as a great variety of textures and mineral combinations. The outcrops of country rocks examined and the aeromagnetic data indicate that the geological environment for this complex is very similar to that of the Nemegosenda area; that is, gneiss cut by diabase dikes. The important niobium-bearing zones, except for some bodies of apatite and magnetite and a few carbonatite zones, are confined to the foliated rocks. These foliated rocks carry sufficient magnetite to create anomalies, so that ground geophysical surveys readily define these economically important rocks. As far as mineral exploration is concerned, the ground magnetic pattern is of paramount importance, and for this reason the known data have been compiled on Chart A (map case).

52 Geological Report No. 3

TABLE OF FORMATIONS PRECAMBRIAN POST-MATACHEWAN Alkaline and Carbonate Rocks: Mafic dikes. Nepheline syenite. Carbonatite. Foliated ijolitic, malignitic, and syenide rocks. Ijolite, ijolitized breccia. Intrusive Contact MATACHEWAN Diabase. Intrusive Contact LAURENTIAN Gneiss.

Description and Distribution of Rock Types COUNTRY ROCKS The gneiss around the alkaline complex consists of varying proportions of hornblende, feldspar, biotite, quartz, and red garnets. This gneiss is locally reddened, pyroxenitized, and biotitized. Aeromagnetic data indicate that the regional trend of this rock is northeasterly. Gabbroic rock is indicated from the drilling of small magnetic anomalies immediately southeast of the area. In addition to surrounding the complex, gneiss occurs in outcrops and in drill holes in the alkaline complex proper, where it is mostly of a grey feldspathic type and locally replaced by biotite and pyroxene. Quartz, although present in places, was only noted in abundance in fragments of gneiss in a late mafic dike in the east flank. A thin section indicates that both albite and orthoclase feld spars are present. Titanite is a common and very characteristic mineral, especially so of the pyroxenitized facies in drill holes under No. 6 orebody on the Multi-Minerals property (see figures, pages 64 and 65). These gneisses are cut by leucocratic nepheline syenite (type 6), of which there is ample evidence in both drill core and outcrops. No such intrusive contacts exist between these gneisses on the one hand and the ijolite (type 3) and foliated rock (type 4) on the other. If such contacts did exist, they must have been obliterated by later metasomatism. A number of diabase dikes are indicated by drilling, magnetic data, and out crops to occur outside the alkaline complex, but not within it. They trend slightly west of north, are dark green, and resemble dikes of Matachewan age.

ALKALINE AND CARBONATE ROCKS Ijolite and Ijolitized Breccia These are dark-green pyroxene-nepheline rocks apparently formed by the metasomatic replacement of brecciated and fractured rocks. Three general rock types (3a, 3b, and 3c) are distinguished on the geological map (No. 2008, map case). Type 3a is mostly fine-grained, with blebs or intersecting fractures filled with magnetite or nepheline, or both. It is also characterized by many "fragments" of a syenide rock. These fragments consist of a mesh of slender feldspar crystals, and their borders have a "moth-eaten" appearance. There is ample evidence in outcrops to indicate that this rock type developed through the fracturing and brecciation of a pre-existing rock. The fractures are mostly filled with massive magnetite, and the fragments are un- pyroxenitized remnants between intersecting fractures. There is evidence in one outcrop to indicate that the syenitic character of the fragments may also be 53 Niobium-Bearing Complexes East of Lake Superior

metasomatic in origin, and that the pre-existing rock may not have been syenite. The distribution of rock type 3a suggests that it is of later age than the foliated rocks yet to be described. Its niobium content is generally low (0.01 percent Nb2O5); however, higher-grade areas, with pyrochlore in nepheline-filled fractures, do occur. Rock type 3b is similar to type 3a except that magnetite veins and blebs are usually absent. Rock type 3c is found only in the Hebden (Portage) Lake complex and is described in the section on that area, at the end ol this chapter.

Foliated Ijolitic, Malignitic, and Syenitic Rocks Included here are a group of rocks that apparently once ringed the complex but, owing to later syenitic injections, now constitute a number of partial rings. They are typically foliated, and range from melanocratic pyroxene-rich types to near-leucocratic feldspar-rich types. They contain sufficient fine magnetite to cause magnetic anomalies. As a group, they definitely have a higher niobium content than the other rock types of the area. The author believes that they may have a complex history of origin, but suggests that they may have originally been a metasomatic aureole around a central diatreme or plug. An attempt has been made on the geological map (No. 2008, in map case) to divide the rocks into three groups: 4a, 4b, and 4c. Rock type 4a includes the melanocratic types, which are usually pyroxene and nepheline-rich, and rock types 4b and 4c include the mesocratic and near-leucocratic types respectively, which indicate a progressive increase in feldspar and decrease in mafic minerals. The increase in feldspar is accompanied by an increase in grain size. Fragments and xenolith-like features are common to most of the rock types. Elongated, tabular alkali feldspar porphyroblasts are abundant in the more leucocratic types and are usually found in all types. The long axis of these feldspars is generally slightly inclined to the over-all foliation trend. Zones with an abnormal amount of such minerals as garnet, apatite, magne tite, and wollastonite, are found in these rocks. They are also cut by nepheline syenite, carbonatite, and late mafic dikes. On the other hand, the contact between the syenitic type 4c and the nepheline syenites of the core appears to be gradational. Further descriptions of these foliated rocks are given in the section on the Multi-Minerals© orebodies under Descriptions of Properties.

Carbonatite Most of rocks contain calcite as a minor constituent; those in which calcite is the major component make up only a small part of the whole complex. In the general area of Pole Lake, on the north flank, there are some narrow, granular foliated zones of calcite and yellow garnet cutting the foliated silicate rocks. These calcite zones are bordered by a coarse mineral assemblage of nepheline, feldspar, pyroxene, magnetite, and black garnet; in this respect they show a close similarity to some of the mineral combinations associated with foliated carbonatite dikes in the Firesand carbonatite complex. This type of yellow garnet-calcite mineralization also occurs in a drill hole southeast of Daer Lake. Diamond-drilling in the No. 8 pyrochlore-bearing zone on the Multi-Minerals property disclosed two carbonatite dikes. The upper one has been fairly exten sively drilled as a potential carbonate-type niobium zone; it is a typical calcite

54 Geological Report No. 3

carbonatite averaging 80 percent coarse white calcite. The minor constituents are green pyroxene, biotite, apatite, magnetite, and yellow-brown pyrochlore. The accompanying photographs and the sketches of core in the accompanying figures illustrate the general character of this rock and the points discussed below. Its position in No. 8 zone is shown in the figure on page 66.

Sketches of pieces of NX core (natural size) of the pyrochlore-bearing carbonatite dike in No. 8 niobium zone, Multi-Minerals property. The black crystals are pyroxene, the fine stippling is mostly apatite and magnetite, and the pyrochlore crystals are marked P. Note that the pyrochlore occurs imbedded in the calcite crystals as well as along lines of weakness, and that the more mafic streak in the left-hand sketch shows evidence of being a crush-zone cutting across the calcite crystals. The walls of this carbonatite dike are quite sharp, with angular and ragged fragments of wallrock in the dike itself. The wallrock is fractured and locally may be altered or partially altered to a fine-grained pink mosaic of nepheline, feldspar or calcite, or both. The fractures may be filled with calcite or biotite, or both. A narrow selvage of biotite normally surrounds the fragments of wall- rock in the dike proper. These fragments show no signs of a preferred orienta tion, i.e. parallel to the foliation, and may actually be across a line of foliation (see figures above). The author did not detect any preferred orientation for the 55 Niobium-Bearing Complexes East of Lake Superior calcite or pyroxene crystals. Some of the foliation is due to narrow crush-zones with an increased content of accessory minerals; this is illustrated in the figure, which has been carefully traced from specimens of core. Diamond-drilling indicates that this carbonatite dike is lens-like along strike and dip. The origin of this type of carbonatite dike-like body is a controversial sub ject; nevertheless, it may have been formed in openings created by movement along an irregular fault plane, and the foliation, rather than being evidence of magmaflowage, may have been due partly to successive periods of deposition from solutions and partly to crush-zones created by movement along the fault. This possibility is specially noted because, if correct, then the emplacement of the bodies is structurally controlled, and a predictable pattern for their bulging and pinching may exist. Nepheline Syenites Three general varieties have been recognized, although the mapping has not been done in sufficient detail to define adequately their distribution and relation to one another. Rock type 6a is a generally equigranular, medium-grained, near-leucocratic type, exposed mostly along the gorges on the north flank. It consists mainly of about equal amounts of nepheline and alkaline feldspar and about 20 percent mafic minerals, mostly pyroxene but including also magnetite and biotite. No distinct contact can be drawn between this type and the foliated syenide types to the north; in fact, there is evidence that the area marked on the map as under lain by this type also contains partially assimilated zones of the foliated rocks. Rock type 6b includes a group of mesocratic to near-melanocratic syenide types. Normally they are medium to coarse-grained and range from a granitoid to a porphyritic texture. Generally they consist of about equal parts of mafic minerals sodic pyroxene or black biotite, or both, and leucocratic minerals feldspar or nepheline, or both. The two main areas in which these rocks are known to occur are those where the foliated rocks tend to finger out on the northwest and northeast flanks. The rocks were also cut in drill holes on the inner side of zones of foliated rocks of type 4 on the northeast flank, drilled by Claymac Mines, and on the south flank, drilled by Apaniag Mines Limited and Dominion Gulf Company. A few outcrops of a distinctly porphyritic type occur on the west flank, and one outcrop is cut by a coarse leucocratic nepheline syenite dike. Rock type 6c is a leucocratic, coarse-grained, inequigranular nepheline syenite, consisting of laths of alkali feldspar in a nepheline matrix. The mafic minerals are biotite and pyroxene, and seldom constitute over 10 percent. The feldspar laths are often crudely oriented, giving a semi-foliated texture. The main exposures of this rock are in the outer part of the complex, and in fact there is sufficient evidence to suggest that a complete ring of this rock type comprises the outer zone of this alkalic structure. Dikes of this rock type are found cutting the gneisses, the ijolitic breccias (rock type 3), and the foliated rocks (rock type 4). A few drill holes and outcrops in the inner part of the structure provide evidence to suggest that this rock is present there, but the author would be unwilling to state that it is the dominant rock of the depressed central core. On the east flank there is an area with erratically distributed magnetic anomalies; two drill holes and some exposures indicate that these anomalies are caused by pods and small bodies of apatite and magnetite in this type of syenite (6c). Inclusions of gneiss, some of which are partially replaced by apatite, are also present in this syenite. 56 Geological Report No. 3

Foliated carbonatite with fragments of wallrock. Lowest row of core is wallrock with fractures filled with black biotite and white calcite. Lackner Lake area.

Nepheline syenite cutting feldspar-rich gneiss (upper part of photograph), and with dark pyroxene- biotite-rich fragment (lower right). Camp area at Multi-Minerals Limited, Lackner Lake area.

57 Niobium-Bearing Complexes East of Lake Superior

Mafic Alkaline Dikes Dark, fine-grained dikes are found throughout the area, cutting both the alkaline and gneissic rocks, but are possibly more prevalent in the latter. Their composition is indicated, by a number of thin sections, to be variable; usually the major constituents are pyroxene, biotite, feldspar, and calcite, with occasional fresh olivine. The accessory and secondary minerals include magnetite, apatite, scapolite, sodic amphibole, chlorite, etc. One of these dikes, traced by drilling on the Multi-Minerals property, appeared to be a thin sheet-like mass dipping gently outwards. A similar trend was noted for a dike at surface on the former Dominion Gulf Company property on the east flank. This dike has abundant angular fragments of coarse leuco cratic nepheline syenite, as well as definite fragments of a quartz-bearing gneiss. This would indicate that the material had moved from the gneiss through the outer coarse nepheline syenite ring. A ring-like feeder source in the gneiss is indicated for these near-flat dikes. Some drill holes show many of them to be present, confirming the view that most of them may be nearly-flat lying.

Structure Plotting of magnetic data illustrates the circular pattern inherent to the area. This circular pattern is also confirmed by the distribution of the major rock types and by the foliation present in some of these types. Drilling by Multi-Minerals Limited in the general area of their orebodies indicated dips as flat as 45 degrees inward for the foliated rocks, carbonatite dikes, and the outer ring of coarse leucocratic nepheline syenite. The dips of foliation in the outcrops are generally steeper, and in some cases are nearly vertical. Magnetic data indicate that the main mass of foliated rock, as exposed on the west flank, breaks and fingers into several zones as it swings around into the other flanks; these zones are separated by syenite. This suggests that there may be more than one ring, or partial ring, of injected nepheline syenite. Late faulting is indicated by topographical depressions, and confirmed in some cases by interruptions in the magnetic pattern. Some of these probable faults are shown on the geological map (No. 2008, map case).

MAGNETIC DATA AND RADIOACTIVITY

The whole alkaline complex has been covered by the ground magnetic surveys of various companies. The results of these surveys have been compiled on Chart A (in map case). Although this type of compilation is rather unsatis factory owing to difference in instruments, operators, base magnetic values, etc., nevertheless the close association of niobium mineralization with magnetite- bearing formations strongly justifies presentation of this data. The surveys, on ground held by M. Silverman and on that originally held by Dominion Gulf Company, are indicated to have a comparable base gamma value, so this base gamma value was accepted for the compilation. The magnetic readings over ground held, or formerly held, by Multi-Minerals Limited and on the Le Brasseur, Derraugh, and MacDonnell property were reduced by 7,500 gammas, and the surveys by Claymac Mines Limited were reduced by 4,000 gammas, so that they would be roughly comparable in magnetic intensity to the surveys mentioned above. For the isolated Hebden Lake complex, the gamma values are presented as so much above the base level for the immediate area. 58 Geological Report No. 3

The stronger anomalies, i.e. those over 5,000 gammas, are due to magnetite veins or blebs in ijolite breccia, to massive magnetite-apatite bodies, or to a replacement of foliated rocks by these minerals. The foliated ijolites and malignitic rocks give distinct linear anomalies, generally under 5,000 gammas. The intrusive syenites, even when melanocratic, are relatively non-magnetic. Radioactivity is widespread throughout the complex and is particularly noticeable in the foliated rocks and ijolites. It is generally most pronounced in the rocks that contain such minerals as apatite, dark-green garnets, and mag netite. It is due both to pyrochlore and rare-earth minerals such as monazite. As in the Nemegosenda area, rare-earth minerals usually cause the highest radioactive anomalies.

Feldspathic gneiss cut by alkaline mafic dikes in Multi-Minerals Limited camp area. Lackner Lake area.

ECONOMIC GEOLOGY

Mineralization The complex has been the object of extensive exploration for magnetite, apatite, and niobium. All zones of any size found to date are restricted to the wrest flank on ground held by Multi-Minerals Limited, which is in the area where the mafic metamorphic-type rocks are most prevalent. Niobium is present in all the alkaline rocks as a minor constituent. The mafic facies of rock types that might be classed as replacement, metasomatic, or metamorphic in origin, in contrast to distinctly intrusive types, contain niobium usually in excess of 0.10 percent Nb2O5. In the Multi-Minerals© No. 8 zone there is distinct evidence that the higher-grade zones are due to additional pyrochlore along irregular stringers and fractures, and in narrow altered zones.

59 Niobium-Bearing Complexes East of Lake Superior

In the area of Nos. 3, 4, and 5 zones there is evidence to suggest a close spatial association of the pyrochlore with zones replaced by apatite; the sections richer in pyrochlore lying between the apatite-rich sections. The pyrochlore-bearing mafic rocks (ijolitic and nialignitic types) in the Lackner area are of comparable type to those rocks called pyroxenide fenites in the East ore zone in the Nemegosenda Lake area. There, however, assays of specific mineralogical bands have shown definitely the close association of higher niobium values with zones richer in such minerals as apatite, finely disseminated or fine-grained magnetite, green garnet, and possibly, wollastonite. In the Multi- Minerals property in the Lackner area an association of this type is not visually evident or indicated in the assays, although apatite and magnetite are definitely present, and are an important constituent of the better niobium-bearing zones. Garnet has not been noted in the Multi-Minerals ore area, and zones rich in wollastonite show no enrichment in niobium mineralization. On the other hand, in the fire tower section of the Lackner area, mineralization consisting of apatite, magnetite, pyroxene, and green garnet does contain about l percent Nb2O5. However, the evidence indicates that it occurs in small lenses rather than zones of any linear extent. E. H. Nickel, who made mineralogical studies of both the pyrochlore in the ijolite wallrock zone (Nickel 1955) of No. 6 body and in No. 8 zone (Nickel 1956) on the Multi-Minerals property, reports the pyrochlore is different in the two zones. The chief differences that he notes are: (1) the No. 6 zone pyrochlore is metamict, but that in No. 8 zone gives a weak X-ray pattern without ignition; (2) the No. 6 zone pyrochlore contains approximately 17 percent combined U.fO8 and ThO2, but No. 8 zone contains only l percent U:jO9 and no thorium; and (3) the pyrochlore in No. 8 zone contains nearly four times as much iron and titanium as that in No. 6 zone.

Description of Properties APAMAG MINES LIMITED Early in 1955 this company drilled four holes, totalling 1,089 feet, on a 27-claim block in the southeastern part of the area. A fifth hole, 1,041 feet, was completed in 1957. Twenty-two of these claims were previously held by Dominion Gulf Company who had covered them with a magnetometer survey. The claims have been allowed to lapse. The holes are plotted on the geological map (No. 2008, map case). CLAYMAC MINES LIMITED Claymac Mines Limited held thirty claims in Lackner township on the north and northeast flank of the alkaline complex. They completed a ground magnetometer survey, and nine holes, totalling 2,722 feet in 1954. By 1958 the claims had been reduced to eight, all on the northeast flank. The magnetometer survey located only one anomaly of any linear extent; this was tested by three holes (Nos. 5, 6, and 7). The anomaly was due to a fine- textured, foliated ijolitic horizon bordered by nepheline syenite. The highest Nb2O5 content was in hole No. 6, which averaged 0.13 percent from 203 to 274 feet. 1 DOMINION GULF COMPANY In 1951 this company completed an aeromagnetic survey that covered the alkaline complex, and staked thirty claims on the east flank of this area in Lackner

Assays filed with assessment report for diamond-drilling.

60 Geological Report No. 3 township. In 1952 they carried out a geological and magnetic survey of these claims, and in 1954 carried out additional geological and magnetic studies, and completed three diamond-drill holes totalling 1,988 feet. This work indicated low linear magnetic anomalies associated with foliated intermediate to mafic alkaline rocks, and strong isolated anomalies associated with granular apatite-magnetite pods and bodies in nepheline syenite. Hole No. l, testing the strongest and largest anomaly of the latter type, cut 200 feet of almost massive apatite-magnetite, from 400 to 600 feet in the hole. Informa tion supplied by Dominion Gulf Company indicates that this material averaged 39.0 percent Fe (soluble), 5.0 percent P, and 0.15 percent Nb2O5. A mafic en velope surrounding this body gave slightly higher assays in niobium. Magnetic data indicated this body to be too small to warrant further testing, and the claims were allowed to lapse.

Le BRASSEUR—DERRAUGH—MacDONNELL PROPERTY Three privately incorporated companies, Le Brasseur Lackner Incorporated, Derraugh Lackner Incorporated, and MacDonnell Lackner Incorporated, were formed by Buffalo, N.Y., interests on claims around and east of the fire tower in Lackner township. These interests at present hold six patented claims (S.53643- 45, S.54097-98, and S.54101). Initially they also held four surveyed claims (S.58584-87). They completed a magnetometer survey, and in 1952 drilled four holes totalling 1,007 feet to locate the cause of the higher magnetic anomalies. This work was done before interest developed in niobium, and no work has been done since. Rock outcrops are fairly plentiful, and the claims cover the foliated rocks on the north flank that are a potential location for niobium mineralization. Small highly radioactive pods of apatite and magnetite have been noted by the author, and samples taken by him assayed up to l percent Nb2O5. In addition, narrow pyrochlore-bearing syenite dikes are present. A body of granular calcite and yellow garnets is indicated by boulders and a few outcrops; however, the niobium content of this body would appear to be quite low.

MULTI-MINERALS LIMITED This company holds 51 patented claims covering most of the west flank of the complex. These claims include a group previously held by Nemegos Uranium Corporation, who optioned them to Northrim Exploration Company in 1953, who in the same year sold them in turn to Multi-Minerals Limited. Magnetic and geological surveys and over 66,000 feet of diamond-drilling had been completed by the end of 1958. Metallurgical extraction tests have been made on the magnetite-apatite as well as on the niobium-bearing bodies. The magnetic anomalies have been given numbers by the company officials, and associated mineralized zones have been given the same number; these numbers have been retained in this report.

Nos. 3, 4, and 5 Anomaly Zones This is an anomalous area about 3,000 feet long, consisting of two main linear anomalies, which appear to terminate at both ends in strong cross faults. This 3,000-foot length is also indicated to be divided into three sections by two more faults with several hundred feet of horizontal displacement. The locations of the mineralized zones are shown in map No. 2008, and anomalies are shown 61 Niobium-Bearing Complexes East of Lake Superior

on Chart A. The accompanying figure is a vertical cross-section through No. 3 and No. 4 zones. Company officials estimated in their annual report for 1955 that the No. 3 and No. 4 zones contain 10,000,000 tons grading 15.5 percent magnetite, 19.5 percent apatite, and 0.23 percent Nb2O6 .

R39 R53

Vertical section across Multi-Minerals© No. 3 and No. 4 zones. Note that the niobium mineralization is associated with the same general zone as the apatite-magnetite mineralization, but that the niobium content is not directly proportional to the amount of that mineralization. Assays supplied by Multi-Minerals Limited. Lackner Lake area.

The mineralization is essentially apatite replacing foliated to massive dark- green ijolitic rock. Sufficient magnetite accompanies the apatite to cause mag netic anomalies of several thousand gammas above the neighbouring areas. The pyrochlore is readily visible in the medium-grained ijolite, between sections rich in apatite. It occurs as finely disseminated grains and along irregular seams, without any apparent alteration of the adjacent rock. Visually, there is little apparent macroscopic difference between the ijolitic rocks of the higher-grade niobium zones and the ijolites in the hanging wall, except possibly the former are less foliated and more massive. 62 Geological Report No. 3

In some of the holes penetrating well into the footwall of the southern part of the zone, there is evidence that these rocks are pyroxenitized or partly pyro- xenitized gneiss, which is in turn underlain by nepheline syenite. The footwall of the northern part of the zone is nepheline syenite.

No. 6 Body This body is a very uniform mass of granular magnetite and apatite. It has been thoroughly tested and outlined by diamond-drilling. It strikes northwest and dips more or less vertically. It has a maximum length of 800 feet and a maximum width of 200 feet, and tapers to a point at a vertical depth of between 400 and 500 feet below surface. Company officials estimate that it contains 5,000,000 tons grading 70 percent magnetite, 22 percent apatite, and 0.17 percent

Pitted weathered surface of the foliated rocks of niobium zone No. 8, Multi-Minerals Limited. Lackner Lake area.

Nb2O5. The magnetite is titaniferous; the niobium mineral has been identified as pyrochlore, and the mineralization is quite radioactive. In addition to these minerals, there is a small amount of pyroxene and pyrrhotite. Occasionally mas sive veins and spots of magnetite, as well as seams of pure apatite, occur in the granular-type mineralization. The rocks surrounding the body are chiefly ijolitic types ranging from a rather uniform to the very blotchy types previously described as ijolite rock type 3a. Some of the syenite that alters to this ijolite type occurs on the south side. A syenite dike occurred in the body near the east wall of the pit, but the evidence was not clear as to whether it cut the apatite-magnetite mass or was a pre-existing dike that was not replaced. The walls of the massive mineralization are sharp, even when there is no evidence of faulting along a contact. All the diamond-drill holes passing through the body at depth along the west and northwest sides, of which fourteen were examined, passed into a different mineralogical zone from that surrounding the body. This disclosed an abrupt 63 Niobium-Bearing Complexes East of Lake Superior

64 Geological Report No. 3

i

5 l

65 Niobium-Bearing Complexes East of Lake Superior

66 Geological Report No. 3 termination of the magnetite mineralization (mostly as veins) common to ijolite rock type 3a, and the appearance of titanite. This titanite-bearing and magnetite- free zone appears directly correctable with similar rocks exposed in the Multi- Minerals© camp area, and on the high ground to the southwest of No. 6 body. It is essentially a leucocratic, feldspathic, and gneissic rock with locally mafic- rich bands and areas, and cut by mafic dikes (see photo on page 59.) The mafic rocks range from pyroxene-rich to biotite-rich, mostly with varying concentra tions of titanite. All these types are cut by coarse-grained nepheline syenite masses and associated stringers and dikelets. Apatite is common and locally plentiful in some of the blocks of gneiss in these syenites. A similar condition was noted on the east flank of the complex, where definite blocks and fragments of gneiss are caught up in nepheline syenite. This same area also has pods and small bodies of massive magnetite and apatite in the nepheline syenite. Pyrochlore Zone in Wall of No. 6 Body About 200 feet south of No. 6 body there is an outcrop of ijolite breccia cut by numerous nepheline-filled fractures carrying considerable pyrochlore. Com pany officials estimate, from five drill holes, there is 2,000,000 tons of possible ore grading 0.28 percent Nb2O5. No. 8 Zone This is predominantly a silicate-type niobium-bearing zone. It lies north of the No. 6 massive apatite-magnetite zone. It has been diamond-drilled along a 1,500-foot length to vertical depths of about 1,000 feet. True widths of up to 1,000 feet averaging slightly over 0.25 percent Nb2O5 are indicated. In this zone there are higher grade sections averaging about 0.33 percent Nb2O5 over widths up to 200 feet wide.1 These higher-grade sections are mainly found in the central and footwall parts of the zone; this is shown on map No. 2008. A vertical section, showing the individual Nb2O5 assays and some of the macroscopically visible features evident in the core, is presented in the accompanying figure. This zone lies in rocks classed as foliated types and dips at 45 160 degrees inward with them. The rocks in the zone generally range from a malignite to an ijolitic malignite in composition. However, in addition to feldspar, pyroxene, and nepheline, they also contain magnetite, apatite, calcite, zircon, sulphides, and pyrochlore. The magnetite occurs as finely disseminated grains or aggre gations throughout the zone but never occurs as veins. Feldspar porphyroblasts are generally present. A foliated, finely fragmental fabric is very characteristic of the zone (see figure opposite); however, coarser-grained, more granitoid, massive types are also present. The higher-grade niobium values are mostly associated with more granu lated sections with shred-like fragments and altered streaks, which have a pale grey or straw-yellow cast. Fine pyrochlore is normally visible along these streaks; it also occurs as scattered grains throughout the zone. Two carbonatite dikes are present in the zone (see figure opposite). The upper one has been extensively drilled as a carbonate-type orebody and is described below as the "calcite zone". On both sides of these dikes the host rocks contain other narrow carbonatite "dikelets" and calcite veins. In addition, there are dense, pink altered zones consisting of a fine-grained mosaic of nepheline and feldspar with or without calcite. Biotite is also abundant. The evidence does not indicate that this alternation is accompanied by an increase in niobium, in fact, it may cause a slight dilution of the niobium content.

Averages calculated by the author from assays supplied by company officials. 67 Niobium-Bearing Complexes East of Lake Superior

Calcite Zone This is the company©s designation for the carbonatite dike mentioned above. It has been drilled along a 500-foot length, and it pinches and bulges along that length as well as in dip. The greatest true width encountered was 100 feet. The indicated grade is variable, but may average slightly under 0.20 percent Nb.2O5 . The character of the zone has been described in the section on carbonatites. The typical distribution of the pyrochlore in this zone is shown in the figure on page 00. Company officials report that tests indicate that a pyrochlore con centrate can be produced from this material by simple mechanical means.

ONTARIO RARE METAL MINES LIMITED In 1954-55, this company completed a magnetometer survey, and five dia mond-drill holes totalling 2,281 feet, on twenty-seven claims in the southeastern part of McNaught township. This work indicated that the claims were underlain by gneisses and cut by northerly-trending diabase dikes. In the area of holes Nos. 1-4, the magnetic data indicate many faults trending in a northeasterly direction, near which there are many isolated small magnetic highs. The drill holes encountered much faulting as well as gabbroic rocks. The gneisses that were cut in the drill holes are locally reddened and pyroxenitized or biotitized, or both. They are also cut by numerous mafic dikes. Only traces of niobium were obtained in assavs of the core.

M. SILVERMAN CLAIMS This group consists of sixty-eight claims in the southern part of Lackner township and the southeastern part of McNaught township. In 1954 a magneto meter survey, and fourteen drill holes, totalling 4,117 feet, were completed. This group is situated immediately south and east of the Multi-Minerals group. The magnetometer survey indicated several anomalous areas on the east and south flanks of the alkaline complex. These anomalous areas were tested by short drill holes; the holes are shown on map No. 2008, and the anomalies on Chart A. Hole No. 9 indicated that the anomaly in that area is due to magnetite in nepheline syenite; hole No. 10 indicated this anomaly to be caused both by mafic rocks and magnetite veins. The rest of the drilling indicated that the anomalies were mostly due to mafic bands bordered by nepheline syenite. The niobium analyses obtained from the split core ranged up to a maximum of 0.29 percent Nb2O5 over 5 feet, but the more mafic foliated rocks generally ranged from 0.07 to 0.14 percent Nb2O6 , according to information supplied by M. Silverman.

HEBDEN (PORTAGE) COMPLEX A distinctly circular, magnetically anomalous area exists as an outlier to the main Lackner alkaline complex northeast of Hebden (Portage) Lake in Lackner township. This anomalous area is 3,000 feet in diameter. In 1954, Chyka Mines Limited made a ground magnetic survey of the area and tested it with twenty-eight diamond-drill holes. The author briefly checked the core and examined a few of the surface exposures. 68 Geological Report No. 3

The drilling indicates that this magnetically anomalous area is underlain chiefly by ijolite. The ijolite consists of nepheline, pyroxene, and minor amounts of titanite, magnetite, apatite, calcite, and sulphides. In texture it ranges from a fine-grained to a very coarse pegmatitic rock. Its contact with the surrounding gneiss is gradational; pyroxene, nepheline, and minor titanite and calcite have formed in fractures and along the foliation of the contacting gneisses. Although the magnetic anomaly is distinctly circular, its internal pattern is extremely erratic, with variously oriented linear, as well as crescent-shaped, anomalies. Drilling indicates that these zones are ijolite partly to completely replaced by biotite, magnetite, and calcite.

REFERENCES

Bell, Robert 1883: Map showing approximately the geology of the basin of Moose River and adjacent country; scale, l inch to 8 miles. Map 159, Geol. Surv. Canada, 1883. This map accompanies Report of Progress for 1880-1-2, pt. C, sec. 1. C. I. M. 1957: Mining geophysics; Canadian Institute of Mining and Metallurgy, Congress volume, 6th Commonwealth Mining and Metallurgical Congress, 1957. Frohberg, M. H. 1937: The gold deposits of the Michipicoten area; Ontario Dept. Mines, Vol. XLIV, 1935, pt. 8. Gledhill, T. L. 1927: Michipicoten gold area, District of Algoma; Ontario Dept. Mines, Vol. XXXVI, 1927, pt. 2. Haanel, B. F. 1909: Summary Report for 1909; Mines Branch, Dept. Mines Canada. Harding, W. D. 1950: Preliminary report on the geology along the Mississagi Road; Ontario Dept. Mines, P. R. 1950-6, 1950.

Hodder, R. W. 1958: Alkaline rocks and niobium deposits near Nemegos, Ontario; Geol. Surv. Canada, Paper 57-8. Moore, E. S. 1932: Goudreau and Michipicoten gold areas, District of Algoma; Ontario Dept. Mines, Vol. XL, 1931, pt. 4. Neczkar, E. 1958: Paragenesis of rock-forming minerals of nepheline syenite and adjacent wallrocks near Nemegos, Ontario; Master©s thesis, University of Toronto, 1958. Nickel, E. H. 1955: Interim MD test report No. 710ML; Mines Branch, Dept. Mines & Tech. Surv. Canada 1955. 1956: Report No.©MD 3112; Mines Branch, Dept. Mines & Tech. Surv. Canada, 1956.

Pecora, W. T. 1956: Carbonatites: a review; Bulletin, Geological Society of America, 1956, Vol. 67, No. 11. Von Eckermann, H. 1948: The alkaline district of Alno Islands; Sveriges Geologiska Undersokning, No. 36, Sweden, 1948. 69

INDEX

Circular structures...... 12, 27, 34, 56, 68 Acknowledgments...... 23, 33, 51 Magnetic anomalies...... 28, 44, 58 Aegirite...... 3, 36, 46, 48 See also Ring structure. Niobium assoc. with...... 45, 49, 50 Clay calcite, analysis...... 5 Africa, volcanic necks ...... 7-9 Claymac Mines Ltd...... 60 Age relations...... 10 Collins tp...... 35,36,41,46 Algoma district Columbium. See Niobium. Firesand R. area ...... 23-32 Contact rocks...... 40, 44 Scabrock L.area...... 11-22 Continental Wood Products...... 50 Algoma Ore Properties Ltd...... 23, 29-32 Core rocks...... 18 Alkaline rocks...... 20, 33, 41, 53 Dolomite...... 26, 28, 30 Fenite...... 34, 36, 49,50 Syenite...... 34, 41 Alteration...... 10 Country rocks...... 7, 24, 35, 53 Fenite...... 36, 49 Granite...... 13 Gabbro...... 36,37 Gneisses...... 35, 36 D Granite...... 13-15, 19 Derraugh Lackner Inc...... 61 Greenstones...... 25 Diabase...... 10, 13 Nepheline...... 43 Dolomitic core rock...... 26, 28, 30 Analyses, spectrographic...... 5, 6, 29 Dominion Gulf Co...... 33, 51, 60 Apamag Mines Ltd...... 60 Nemegosenda Lake property...... 46-50 Apatite...... 45, 60-67 Aubrey Falls...... 11, 13 Aureoles. Economic geology. Magnetic...... 22 Firesand R. area...... 29-32 Metasomatic...... 34, 44, 54 Lackner L. area ...... 59-69 B Nemegosenda L. area...... 45-50 Seabrook L. area...... 20 Basic dikes...... 13, 27 Biotite pegmatite...... 39, 40 Biotite pyroxenite ...... 14,17 Borden tp...... 3 Faulting...... 49,61 Breccia. Fenites. Granite, notes and photos...... 13-16 Alkaline...... 34, 36, 50 Ijolitic...... 7,53,67 Alteration...... 10, 36, 49 Mafic...... 18, 20 Magnetic data...... 44 Malignite...... 48 Mineralization...... 45, 49 Sovitic...... 40 Origin...... 7, 10 Syenitic...... 40, 41 Pyroxenitic...... 36-39 Burton, A. and M...... 51 Term defined...... 3 Bussineau, W...... 11, 20 Fenitization. Of gneisses...... 35 C Of granite, notes and photos. . . 13-15, 19 Firesand River area. Calcite. See Carbonate. Carbonates, analyses...... 5, 6 Canadian I nternational Paper Co...... 50 Map, geological...... in map case Carbonate. magnetic...... 28 See also Carbonatite. Report on...... 23-32 Analyses, spectrographic...... 5 Rock types...... 7 Veins...... 43 Foliated rocks...... 7, 44 Carbonate-alkaline complexes. . . 12, 24, 33, 53 Photos...... 19,27,30,57,63 Origin and age ...... 6,10 Formations, tables of...... 13, 24, 35, 53 Sections ...... 8,9 Foyaite...... 3, 41 Carbonatite...... 26 Analyses, spectrographic...... 6 Foliated, photos...... 16, 19, 27, 30, 57 Lackner L. area...... 54-56,67 Gabbro, notes and photos...... 35-37 Niobium in...... 20, 29, 32, 55, 68 Garnetiferous rocks. Origin, magmatic...... 7, 10 Carbonatite...... 54 Porphyritic...... 26 Fenite...... 38,39 Seabrook L. area...... 18-20 Gneiss...... 35, 53 Term defined...... 3 Niobium in...... 45, 60 Cargill complex ...... 5,10 Silicate, mafic...... 25, 26 Chewett tp...... 33,41,46,49,50 Garvie, H.L...... 3, 51 Chvka Mines Ltd...... 68 Geochemistry...... 4-6 71 Niobium-Bearing Complexes East of Lake Superior

Geology, economic. See Economic geology. Malignite...... 39, 42, 48 Geology, general...... 6-10 Niobium in...... 46, 49, 67 Firesand R. area...... 24-27 Term defined...... 3 Lackner L. area...... 52-58 Mapping, notes on...... 12, 23, 33, 52 Nemegosenda L. area...... 34-44 Maps, geological, coloured. Seabrook L. area...... 12-20 Firesand R. area...... in map case Geology, structural...... 27, 43, 58 Lackner L. area...... in map case Gilbert, George S...... 12, 23 Nemegosenda L. area...... in map case Gneisses...... 35, 53 Seabrook L. area...... in map case Fenitized...... 35, 36 Maps, magnetic...... 21, 28 Mafic dikes in, photo...... 59 Lackner L. area...... in map case Goodwin, A. M...... 23 McGeetp...... 43, 50 Granite...... 13 McNaughttp...... 51, 68 Breccia, fenitized, notes and Metasomatism. photos...... 13-16 See Alteration; Aureoles. Inclusions, photo...... 19 Miascite...... 42 Greenstone, notes and photo...... 24-27 Michipicoten area. See Firesand R. area. H Mineralization...... 20, 29, 45, 59 Harding, W. D...... 11 Mineralogy of the complexes...... 4-6 Hatch, H. B...... 3 Monazite...... 50, 59 Hebden Lake complex...... 7, 68, 69 Morrison, N. and R...... 23 Hematite...... 19, 20, 26, 29 Claims, notes and photo...... 30 32 Historical notes...... 2, 11, 51 Multi-Minerals Ltd...... 51 Hodder, R. W...... 51 Property, report and sections. . . . .61-68 I N Ijolite...... 14, 36, 53, 54, 69 Neczkar, E...... 51 Magnetic intensity...... 22, 59 Nemegos Uranium Corp...... 3, 51, 61 Niobium in...... © ...... 20, 62, 63 Nemegosenda Lake area...... 3 Origin...... 7, 10 Map, geological...... in map case Photos...... 17,37 Report on...... 33-50 Term defined...... 3 Rock types...... 7 Inclusions, granite, photo...... 19 Nepheline rocks...... 3 Intrusives, alkaline...... 41-43 See also Ijolite; Nepheline syenite. Nepheline syenite...... 7, 41, 56 J Alteration...... 43 Jacupirangite...... 34, 39, 45, 50 Apatite-magnetite in...... 61 Term defined...... 3 Emplacement of...... 10 Jarvis, W...... 23,32 Photos...... 42,57 Juvite...... 3,41,42 See also Malignite. Nickel, E. H...... 60 K Niobium. Kapuskasing area ...... 5,10 See also Pyrochlore. Keewatin greenstones...... 24-27 Assays../...... 20, 30, 62, 66 Krimpotich, F...... 23, 32 Ore reserves...... 46, 62, 63, 67 Uses...... l Nomenclature, geological...... 3 Lackner Lake area. Northrim Exploration Co...... 61 Carbonates, analyses...... 5, 6 Map, geological...... in map case O magnetic...... in map case Ontario Rare Metal Mines Ltd...... 68 Report on...... 51-69 Ore reserves...... 46, 62, 63, 67 Rock types...... 7 Lamprophyre...... 20, 27 Le Brasseur Lackner Inc...... 61 Limestones, magmatic...... 7 Pegmatite...... 39, 40, 50 See also Carbonatites. Pole Lake...... 54 Porphyritic carbonatite...... 26 M Porphyry, feldspar...... 43 MacDonnell Lackner Inc...... 61 Portage Lake...... 68 Mafic rocks...... 25, 43, 58 Properties, descriptions of...... 29, 46, 60 Breccias...... 18, 22 Pulaskite...... 3, 41 Photo...... 59 Pyrochlore...... 20 Pyrochlore in...... 60 Analysis, spectrographic...... 29 Magnetic data...... 20, 28, 44, 58 Assoc. with magnetite...... 45 Maps...... 21, 28, in map case Firesand R.area...... 29-32 Magnetite...... 32, 53 Lackner L. area...... 55,59-69 Lackner L. area,...... 59-69 Nemegosenda L. area...... 45, 49, 50 Niobium in...... 20, 29 Pyroxenite...... 14, 50 72 Geological Report No. 3

Pyroxenitization. Sudbury district. Fenites...... 36-39 See Lackner L. area; Nemegosenda Granite...... 13, 18 L. area. Greenstones...... 25 Surveys, geological...... 2, 23, 33, 51 Syenite. Q See also Nepheline syenite. Quart7-carbonate veins...... 43 Core rock...... 34 Magnetic data...... 44 R Radioactivity...... 22, 29, 45, 59 T In fenite...... 36 Tarbutt Mines Ltd...... 12, 21, 22 Rare-earth minerals...... 45, 46, 50, 59 Temple, A. K...... 33, 36 Ring structure...... 26, 28, 44,54 Thorium...... 45, 46, 60 See also Circular structures. Titanite...... 53, 67 Topography...... 12, 24, 33, 52 Trout Lake. See Nemegosenda L. area. Sander, G. W...... 20 Savage, W. S...... 51 U Sea b rook Lake area. Uranium...... 46, 60 Carbonate, analyses...... 5, 6 See also Pyrochlore. Map, geological...... in map case magnetic ...... 21 V Rock types...... 7 Veins, carbonate...... 43 Sections. Volcanic necks, notes and sections...... 7-10 Carbonate-alkaline complexes...... 8, 9 Volcanic rocks...... 24 Dominion Gulf property...... 47 Multi-Minerals property...... 62, 64-66 Volcanic necks, Africa...... 8, 9 Wollastonite...... 38, 45, 60 Silicate rocks...... 4, 25, 26, 39 Wyckoff, R. D...... 33 Silverman, M...... 68 Sovite...... 3,40 Structures...... 20, 27, 43, 58 Zirconium ...... 46

2,000—1961—3,222 73

Niobium Report Chart A Lackner Lake Area Ground Magnetics

Salt l kick to SO mta

SYMBOLS

Open muskeg, swamp or marsh, with boundary.

Muskeg or swamp, with boundary.

Motor road.

Wagon road.

Township boundary, approximate loca tion only.

Property boundary, surveyed, approxi mate location only.

Property boundary, unsurveyed, ap proximate location only.

Picket line.

Building.

Magnetic contour, value in hundreds K N E R of gammas above base level of area.

NOTE

Magnetic data compiled by G. E. Parsons from geophysical surveys by mining companies and individual claim holders.

LIST OF PROPERTIES 1 Claymac Mines, Ltd. 2 LeBrasseur-Derraugh-MacDonnell. 3 Multi-Minerals, Ltd. 4 M. Silverman.

" fef vT~?

Scale: l inch to tt mile Published 1961 Chart A. Map of the Lackner Lake Area showing Ground Magnetic Contours. Map 2005 ONTARIO SEABROOK LAKE AREA DEPARTMENT OF MINES

HON. JAMES A. MALONEY, Minister of Mines D. P. Douglass, Deputy Minister M. E. Hurst, Provincial Geologist

83018©

47000'

Scale l Inch to SO mil

LEGEND

PRECAMBRIAN

POST-MATACHEWAN CARBONATE AND ALKALINE ROCKS

Mafic alkaline dikes*

Miscellaneous rocks. SYMBOLS

Carbonatite. Muskeg or swamp with boundary. Mafic breccia. Motor road.

Ijolite, pyroxenite and related breccia. Wagon road.

Fen it ized granite breccia. Small rock outcrop.

Fenitized granite. Boundary of rock outcrop.

Geological boundary, defined.

Geological boundary, approximate. INTRUSIVE CONTACT

Geological boundary, assumed. ALGOMAN (?)

Geological boundary as indicated by Granite. geophysical data.

Strike and dip. *0ccurs cutting fenitized granite breccia (4).

Strike and vertical dip.

Strike and dip of foliation. SOURCES OF INFORMATION Strike of vertical foliation. Geology by G. E. Parsons, 1957, 1958.

Fault, assumed. Cartography by F. W. Love, Ontario Department of Mines.

Township boundary, approximate loca Base map derived from surveys of the Division of tion only. Surveys and Engineering, Ontario Department of Lands and Forests, with additional information by S30 18© G. B. Parsons. Building. Magnetic declination approximately 6" West, 1953. Published 196t Map 2005 SEABROOK LAKE AREA

DISTRICT OF ALGOMA

Scale 1:15,840 or l Inch to Y* Mile

Chains 20 10 1 Mile

Feet 1000 O 1000 2000 3000 4000 5000 Feet H H M H H Is

Metres 100 O 0.2 0.4 0.6 0.8 1 Kilometre Map 2006 ONTARIO FIRESAND RIVER AREA DEPARTMENT OF MINES

HON. JAMES A. MALONEY, Minister of Mines D. P. Douglass, Deputy Minister M. E. Hurst, Provincial Geologist

84040'

SYMBOLS

Open muskeg, swamp or marsh. 48000'-

Muskeg or swamp with boundary. Sctfe l inch to H

•s.o. Beaver dam.

Motor road. LEGEND

Wagon road. PRECAMBRIAN

Small rock outcrop. CARBONATE AND ALKALINE ROCKS

Boundary of rock outcrop. Dolomitic core rocks.

Geological boundary, defined. Calcite carbonatite*

2a Mafic carbonate rocks. Geological boundary, assumed. 2b Mafic silicate rocks. 2c Fenitized greenstone.

Strike and dip. COUNTRY ROCKS

Diabase (Matachewan), Strike and dip of foliation.

Granite, syenite (Algoman), Strike of vertical foliation.

Greenstone (Keewatin). Lineament or fault,

Township boundary, approximate loca tion only. *77ie area interpreted as underlain by this rock also included zones of 1 and 2. Surveyed line, approximate location only.

Picket line, approximate location only.

SOURCES OF INFORMATION Building.

Geology by G. E. Parsons, 1958. Drill hole, with number. Geological plans o/ Algoma Ore Properties Ltd. 84040' Visible pyrochlore location, referred to Cartography by F. W. Love, Ontario Department of by letter in report, Mines, Published 1961 Base map derived from surveys of the Division of Survey s and Engineering,Ontario Departmentof Lands and Forests, mining claim surveys and air photo Map 2006 graphs, with additional information by G. E. Parsons. FIRESAND RIVER AREA NOTES DISTRICT OF ALGOMA The designating letters "SSM" have been omitted on this map from the numbers marking the mining claims recorded at the office of the Sault Ste. Marie Mining Division. Scale 1:15,840 or l Inch to 1A Mile Magnetic declination approximately 6" West, 1958.

Chains 20 y. y, 1 Mile

Feet 1000 O 1000 2000 3000 |ii|-|-l M M M-g

Metres 100__O 0.2 0.4 0.6______O.B 1 Kilometre STH M H——-l l————l l l l l l——^ ONTARIO Map 2007 NEMEGOSENDA LAKE AREA DEPARTMENT OF MINES

HON. JAMES A. MALONEY, Minister of Mines D. P. Douglass, Deputy Minister M. E. Hurst, Provincial Geologist

PATTINSON

ALKALINE INTRUSIVES Alkaline syenites: 9a Juvite, coarse, leucocratic, nephe line-r i eh . 9b Malignite, half feldspar, half mafic minerals. 9c Foyaite, one-third nepheline, one- third feldspar, one-third mafic min erals. 9d Pulaskite, feldspar-rich. 9e Foyaite-Pulaskite.

IGNEOUS CONTACT ROCKS

Syenitic breccia and intrusive-contact rocks. NEMEGOSENDA INTRUSIVE REPLACEMENT AND/OR RHEOMORPHIC** ROCKS Carbonate rocks : 7a Calcite carbonatite or sovite. 7b Biot/te-pyroxene-carbonate rock (sovite) and breccias. Silicate rocks: 6a Malignite, malign/tic breccia. 6b Biotite-feldspar pegmatite. 6c Jacupirangite.

Pyroxenide fenite.

lio/itized breccia.

COUNTRY ROCKS intrusives. *** 2a Biotite pyroxenite 2b Gabbro. Gneiss: 1a Dioritic gneiss. 1h Hornblende-feldspar gneiss, le Quartz-feldspar-biotite gneiss

fenitlzed, development of sodic and f or amphibole, reddening , etc.

Magnetically anomalous areas inter MCGEE preted as due to rock types 5, 6 and 8.

*The alkaline rocks are listed approximately m order of formation. However, certain types may have been Introduced at more than one time-period.

* ©Rheomorphic is used for rock material mobilized as a result of chemical change and rise in temperature.

***Fenite is used for ©in situ© metasomatical/y altered country rocks, irrespective of composition, adjacent to an alkaline or carbonatite complex.

****These rocks are listed under ©Country Rocks although they may be part of the alkaline suite.

Muskeg or swamp, with boundary

Small rock outcrop.

Boundary of rock outcrop.

Geological boundary, defined.

Geological boundary, assumed . Boulders 9a

l lb Strike and dip. Quartz-pegmatite dikes

Strike and vertical dip.

Strike and dip of foliation,

Strike of vertical foliation.

Fault, indicated or assumed.

Township line, approximate location only.

Surveyed line, approximate location only.

Higher grade niobium zones, with Do minion Gulf reference letter. (See re port).

SOURCES OF INFORMATION

Geology by G. E. Parsons, 1958.

Cartography by D. F. Jupe, Ontario Department of Mines.

Base map derived from surveys of the Division of Surveys and Engineering, Ontario Department of Lands and Forests, and air photographs, with ad ditional information by G. E, Parsons. The subdivision of Pattinson and Collins Townships was annulled in 1957. Former subdivision posts along the township boundaries are not shown Magnetic declination approximately T West, 1958. Published 1961 Map 2007 NEMEGOSENDA LAKE AREA

DISTRICT OF SUDBURY

Scale 1:15,840 or l Inch to 1A Mile

Chains 20 y. y. 1 Mile IZ Feet 1000 5000 Feet

Metres 100 O 0.2 0.4 0.6 0.8 *f- -fs^ i l l l l ' Map 2008 ONTARIO LACKNER LAKE AREA DEPARTMENT OF MINES

HON. JAMES A. MALONEY, Minister of Mines D. P. Douglass, Deputy Minister M. E. Hurst, Provincial Geologist

47" 50© 470 50

Sctlt l inch to 50 mitn

SYMBOLS

Open muskeg, swamp or marsh, with boundary. Muskeg or swamp, with boundary. LACKNER

LEGEND Wagon road.

PRECAMBRIAN Small rock outcrop.

POST-M AT ACHE WAN

Boundary of rock outcrop. ALKALINE AND CARBONATE ROCKS

Mafic dikes.* Geological boundary, defined. Nepheline syenite intrusives; 6a Leucocratic, grades into 4c. Geological boundary, approximate. 6b Mesocratic to melanocratic, malignite, ijolite, 6c Coarse, leucocratic, inequigranular. Geological boundary, assumed. LACKNER Carbonatite.

Strike and dip. Foliated ijolitic, malignitic and syenitic rocks: 4a Melanocratic, pyroxene-rich. Strike and dip of foliation. 4b Mesocratic. 4c Leucocratic, grades into 6a.

Strike of vertical foliation. Ijolite, ijolitized breccia: 3a Breccia with magnetite veins and A Area of isolated high magnetic blebs. ' anomalies indicating small masses,' 3b 3a without magnetite, Fault, indicated or assumed. ' of apatite and magnetite , 3c Portage Lake type.

Township boundary, approximate loca INTRUSIVE CONTACT tion only. MATACHEWAN Property boundary, approximate loca tion only. Diabase.

Claim line, surveyed, approximate lo cation only. INTRUSIVE CONTACT

LAURENTIAN (?) Picket line. Gneiss: la Unaffected by alkaline solution. 1b Partly fenitized. Location of mining property, surveyed. See list of properties.

Location of mining property, unsur- *0ccurs cutting 1 and 6 in drill holes. veyed. See list of properties.

Building.

Orebody, projected to surface. SOURCES OF INFORMATION

Reference number, Multi-Minerals po Geology by G. E. Parsons, 1958. tential orebody. (See report). Geological plans of mining companies.

Drillhole with number. Letter indicates Cartography by D. F. Jupe, Ontario Department of company. Minos. A Apamag Mines. C Claymac Mines. Base map derived from surveys of the Division of D Dominion Gulf, Surveys and Engineering, Ontario Department of L LeBrasseur-Derraugh- Lands and Forests, mining claim surveys and MacDonnell, air photographs, with additional information by R Ontario Rare Metal Mines. G. E. Parsons. S M. Silverman. No letter Multi-Minerals,

LIST OF PROPERTIES^ The designating letter "S" has been omitted from 1 Claymac Mines, Ltd. the numbers on this map marking the claims recorded 2 LeBrasseur-Derraugh-MacDonnell. 83*05© at the of/ice of the Sudbury Mining Division. 3 Multi-Minerals, Ltd. 4 M. Silverman, Magnetic declination approximately 7" West, 1958. Published 1961 Map 20Q8 LACKNER LAKE AREA

DISTRICT OF SUDBURY

Scale 1:15,840 or l Inch to H Mile

Chains 20 1 Mile

Feet 1000 O 3000 5000 Feet H M M M H ^

Metres 100 O 0.8 —l