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Metamorphic Gold Exploration Timmins Abitibi Greenstone Ontario Geological Survey Open File Report 6101 Toward a New Metamorphic Framework for Gold Exploration in the Timmins Area, Central Abitibi Greenstone Belt 2002 ONTARIO GEOLOGICAL SURVEY Open File Report 6101 Toward a New Metamorphic Framework for Gold Exploration in the Timmins Area, Central Abitibi Greenstone Belt by P.H. Thompson 2002 Parts of this publication may be quoted if credit is given. It is recommended that reference to this publication be made in the following form: Thompson, P.H. 2002. Toward a new metamorphic framework for gold exploration in the Timmins area, central Abitibi greenstone belt; Ontario Geological Survey, Open File Report 6101, 51p. e Queen’s Printer for Ontario, 2002 e Queen’s Printer for Ontario, 2002. Open File Reports of the Ontario Geological Survey are available for viewing at the Mines Library in Sudbury, at the Mines and Minerals Information Centre in Toronto, and at the regional Mines and Minerals office whose district includes the area covered by the report (see below). Copies can be purchased at Publication Sales and the office whose district includes the area covered by the report. Al- though a particular report may not be in stock at locations other than the Publication Sales office in Sudbury, they can generally be obtained within 3 working days. All telephone, fax, mail and e-mail orders should be directed to the Publica- tion Sales office in Sudbury. Use of VISA or MasterCard ensures the fastest possible service. Cheques or money orders should be made payable to the Minister of Finance. Mines and Minerals Information Centre (MMIC) Tel: (416) 314-3800 Macdonald Block, Room M2-17 1-800-665-4480(toll free inside Ontario) 900 Bay St. Toronto, Ontario M7A 1C3 Mines Library Tel: (705) 670-5615 933 Ramsey Lake Road, Level A3 Sudbury, Ontario P3E 6B5 Publication Sales Tel: (705) 670-5691(local) 933 Ramsey Lake Rd., Level A3 1-888-415-9845(toll-free) Sudbury, Ontario P3E 6B5 Fax: (705) 670-5770 E-mail: [email protected] Regional Mines and Minerals Offices: Kenora - Suite 104, 810 Robertson St., Kenora P9N 4J2 Kirkland Lake - 10 Government Rd. E., Kirkland Lake P2N 1A8 Red Lake - Box 324, Ontario Government Building, Red Lake P0V 2M0 Sault Ste. Marie - 70 Foster Dr., Ste. 200, Sault Ste. Marie P6A 6V8 Southern Ontario - P.O. Bag Service 43, Old Troy Rd., Tweed K0K 3J0 Sudbury - Level B3, 933 Ramsey Lake Rd., Sudbury P3E 6B5 Thunder Bay - Suite B002, 435 James St. S., Thunder Bay P7E 6S7 Timmins - Ontario Government Complex, P.O. Bag 3060, Hwy. 101 East, South Porcupine P0N 1H0 Toronto - MMIC, Macdonald Block, Room M2-17, 900 Bay St., Toronto M7A 1C3 This report has not received a technical edit. Discrepancies may occur for which the Ontario Ministry of Northern Devel- opment and Mines does not assume any liability. Source referencesare included in the report and users are urged to verify critical information. Recommendations and statements of opinions expressed are those of the author or authors and are not to be construed as statements of government policy. If you wish to reproduce any of the text, tables or illustrations in this report, please write for permission to the Team Leader, Publication Services, Ministry of Northern Development and Mines, 933 Ramsey Lake Road, Level B4, Sudbury, Ontario P3E 6B5. Cette publication est disponible en anglais seulement. Parts of this report may be quoted if credit is given. It is recommended that reference be made in the following form: Thompson, P.H. 2002. Toward a new metamorphic framework for gold exploration in the Timmins area, central Abitibi greenstone belt; Ontario Geological Survey, Open File Report 6101, 51p. iii Contents Abstract ................................................................................................................................................................ ix Introduction .......................................................................................................................................................... 1 Terminology ......................................................................................................................................................... 2 Acknowledgements .............................................................................................................................................. 3 Methodology ........................................................................................................................................................ 3 Petrography.................................................................................................................................................. 4 Rock Associations and Metamorphic Zones................................................................................................ 4 Metamorphic Grade at Township Scale ............................................................................................................... 5 Keefer Township.......................................................................................................................................... 5 Denton Township......................................................................................................................................... 6 Thorneloe Township .................................................................................................................................... 6 Carscallen Township.................................................................................................................................... 6 Bristol Township.......................................................................................................................................... 7 Ogden Township.......................................................................................................................................... 7 Tisdale Township......................................................................................................................................... 8 Whitney Township....................................................................................................................................... 8 Metamorphism and the Geological Setting of Mineralization.............................................................................. 9 Metamorphism and Deformation................................................................................................................. 9 Metamorphism and Magmatism .................................................................................................................. 9 Metamorphism and Alteration.............................................................................................................................. 10 Metamorphism and Mineralization....................................................................................................................... 11 Pre-metamorphic (Synvolcanic) Magmatism............................................................................................... 11 Archean Regional Metamorphism ............................................................................................................... 11 Syn- to Post-orogenic Archean Contact Metamorphism..............................................................................12 Proterozoic Metamorphism.......................................................................................................................... 13 Conclusions and Recommendations..................................................................................................................... 13 References ............................................................................................................................................................ 14 Appendix 1: Table 2 - Metamorphic Data............................................................................................................ 16 Appendix 2: Table 3 - Location, Grade and Rock Type Data for Figure 2 .......................................................... 42 Metric Conversion Table...................................................................................................................................... 51 FIGURES 1. Townships in study area and distribution of thin sections ........................................................................... 3 2. Preliminary metamorphic map of the Timmins area .................................................................... back pocket 3. Depth-time diagram for mineralized greenstone from Timmins area of Abitibi greenstone belt ................ 12 v TABLES 1. Characteristic minerals and mineral assemblages in low grade, transition, and higher grade zones in eight rock associations/types.................................................................................................................... 4 2. Metamorphic data (location, mineral assemblages, modes, textural observations, alteration) .................... 18 3. Summary of location, grade and rock type data depicted on map................................................................ 43 vii Abstract This report summarizes the results of a pilot study that makes the first step toward a new metamorphic framework for the Timmins camp. The report examines the constraints that metamorphic data and concepts impose on the timing, duration, and nature of deformation, magmatism, alteration and gold mineralization. The data and interpretations are based on reconnaissance petrography of 341 thin sections from locations
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