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THE GEOLOGY, LITHOGEOCHEMISTRY AND PETROGENESIS OF INTRUSIONS ASSOCIATED WITH GOLD MINERALIZATION IN THE PORCUPINE GOLD CAMP, TIMMINS, CANADA by PETER J. MACDONALD Thesis presented as a partial requirement in the Master of Science (M.Sc.) in Geology School of Graduate Studies Laurentian University Sudbury, Ontario © Peter J. Mac-Donald, 2010 Library and Archives Bibliotheque et 1*1 Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A 0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-57704-2 Our file Notre reference ISBN: 978-0-494-57704-2 NOTICE: AVIS: The author has granted a non L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'Internet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distribute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author's permission. In compliance with the Canadian Conformement a la loi canadienne sur la Privacy Act some supporting forms protection de la vie privee, quelques may have been removed from this formulaires secondaires ont ete enleves de thesis. cette these. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n'y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. ••I Canada iii Abstract Most gold deposits within the Porcupine Gold Camp of the Abitibi greenstone belt are spatially associated with porphyry intrusions. These intrusions, however, are present beyond the immediate gold-hosting environment, extending over 80 kilometers along the Porcupine-Destor deformation zone (PDDZ). While petrographically similar, the intermediate to felsic intrusions along the PDDZ represent at least four distinct geochemically defined magmatic suites that span the deformation history of the Porcupine gold camp. The Timmins porphyry intrusive suite (TIS) intrusions are related to magma generated Dl-related crustal thickening related to uplift and extension as a result of flat subduction-related underplating of mafic crust, and resultant delamination and partial melting ca. 2690 Ma during Dl deformation at depths <40 kilometers. These TIS magmas were emplaced near surface and represent subvolcanic intrusions to coeval eruptive equivalents such as the Krist Formation pyroclastic volcanic rocks. Two additional suites of lower crustal sourced magmas, the Carr Township porphyry intrusive suite (CIS) and the granodiorite intrusive suite (GIS) were generated from mafic source rocks 10-15 m.y. later. The CIS was generated by lower crustal melting at shallower depths than the TIS, whereas the GIS was generated at greater depths than the TIS indicating that, in the immediate vicinity of Timmins, D2-related magmatism and thrust stacking significantly thickened the crust to in excess of 40 kilometers. The Holmer intrusive suite (HIS) is a late- to post-tectonic suite formed via the partial melting and fractionation of magma sourced from slab-melt altered mantle at depths >40 kilometers. Gold mineralization has long been recognized to be spatially associated with intrusions proximal to the PDDZ. Although there is no genetic link between spatially related porphyries and mineralization, gold mineralization is associated with sulphidized, sericite ± carbonate altered TIS intrusions emplaced during Dl and to a lesser extent with the late- to post-tectonic HIS and GIS intrusions. The spatial association of gold with the TIS intrusions is related to the intrusions and gold utilizing the same emplacement conduits, presumably reactivated regional faults, as well as the formation of dilation zones surrounding the intrusions during deformation. Similar to gold mineralization, copper mineralization is spatially associated to the Porcupine intrusive suites but does not have a genetic association. iv Acknowledgements This thesis would not have been possible without the interaction and support of many people, organizations and companies. I would like to begin by thanking my thesis supervisor Dr. Stephen Piercey, whose endless amount of patience, support and guidance have been a motivating inspiration to me. I also would like to thank my thesis committee members, Drs. Lafrance, Thurston and Ayer, along with my external examiner, Dr. Beakhouse, whose thoughtful edits have improved this thesis. Acknowledgement is given to the Discover Abitibi Initiative for financial support and the Ontario Geological Survey for publishing preliminary results. Staff from the Ontario Geological Survey are thanked for geological discussions and sharing knowledge of the Timmins region, including Brian Atkinson of the Resident Geologist office and Lindsay Hall and crew. The many companies, and people therein, are acknowledged for access to properties, drill core and logistics, including: The Porcupine Joint Venture (Alastair Still, Keith Green, Peter Harvey, Erik Barr, Bill MacRae, Steve Harding and Michael Nerup), Falconbridge Limited (Damien Duff and Cliff David), Kinross Au Corporation (Ryburn Norman), Lakeshore Au Corporation (Henry Marsden and Jacques Samson) and Tom Exploration Inc. (Chris Dupont). Roger Bateman and Dave Rhys are acknowledged for insight into the structural geology of the area, and Etienne Dinel is thanked for sample collection of porphyry intrusions within the Hoyle Pond deposit. Finally, I would like to thank my family and friends. Geoff for mentoring me into geology, Ed for showing me the results of determination, Dad for the knowledge that anything is possible; and Mom for motivating and enabling me to do so much. Lastly, and most importantly, I want to thank Christine for her love and support, I am not sure where I would be without it. V Table of Contents Abstract iii Acknowledgements iv Table of Contents v List of Figures viii List of Tables x Foreword xi Chapter 1: An Introduction to the Porphyry Intrusions of the Porcupine Gold Camp, Western Abitibi Subprovince, Ontario 1 1.1 Introduction 1 1.2 Geological Overview of the Porcupine Gold Camp 2 1.3 Previous Work 6 1.4 Objectives 9 1.5 Methodology 9 1.5.1 Geological Mapping and Sampling 9 1.5.2 Lithogeochemistry 10 1.6 Thesis Presentation 11 1.7 References 12 Chapter 2: The Lithogeochemistry and Petrogenesis of Intrusions Associated with Gold Mineralization in the Porcupine Gold Camp, Timmins, Canada 22 2.1 Abstract 22 2.2 Introduction 23 2.3 Regional Geological Setting 25 2.4 Geological Attributes 26 2.4.1 Geological Attributes of Porcupine Intrusive Suites 26 2.4.2 Geological Attributes of the Felsic Volcanic Suite 30 2.5 Lithogeochemistry 30 2.5.1 Previous Geochemical Studies 30 2.5.2 Sampling and Analytical Procedures 31 2.5.3 Alteration Geochemistry of the Porcupine Intrusive and Felsic Volcanic Suites ... 33 2.5.4 Lithogeochemistry of the Porcupine Intrusive and Felsic Volcanic Suites 34 2.5.4.1 Lithogeochemistry of the Timmins Porphyry Intrusive Suite (TIS) 34 2.5.4.2 Lithogeochemistry of the Carr Township Porphyry Intrusive Suite (CIS) 36 2.5.4.3 Lithogeochemistry of the Holmer Intrusive Suite (HIS) 37 2.5.4.4 Lithogeochemistry of the Granodiorite Intrusive Suite (GIS) 38 2.5.4.5 Lithogeochemistry of the Felsic Volcanic Suite (FVS) 39 2.6 Discussion 41 2.6.1 Petrogenesis of the Porcupine Intrusive Suites 41 VI 2.6.2 Petrogenesis of the Felsic Volcanic Suite (FVS) 44 2.6.3 Relationship of Voleanism to the Emplacement of the Porcupine Intrusive Suites 45 2.6.4 Geological Differences between Gold Mineralized and Barren Intrusions 45 2.6.5 The Relationship of the Porcupine Intrusive Suites to Gold Mineralization 47 2.6.6 The Relationship of the Porcupine Intrusive Suites to Copper Mineralization 50 2.7 Conclusions 51 2.8 References 53 Chapter 3: Summary and Direction of Future Research 94 3.1 Key Conclusions 94 3.2 Potential Direction for Future Research 96 3.3 References 98 Appendix A: Porphyry Intrusions of the Porcupine Gold Camp, Western Abitibi Subprovince, Ontario 100 A.l Abstract 100 A.2 Introduction 101 A.3 Previous Work 102 A.4 Regional Geology 103 A.5 Geology: Quartz Feldspar Porphyries 106 A.5.1 Timmins Porphyry Intrusive Suite - Main Camp 106 A.5.1.1 Field Relationships 107 A.5.1.2 Petrography 109 A.5.1.3 Alteration, Veining, and Mineralization 110 A.5.1.4 Deformation 113 A.5.1.5 Geochronology 114 A.5.2 Timmins Porphyry Intrusive Suite - Other 114 A.5.2.1 Field Relationships 115 A.5.2.2 Petrography 117 A.5.2.3 Alteration, Veining, and Mineralization 118 A.5.2.4 Deformation 119 A.5.2.5 Geochronology 120 A.5.3 Carr Township Intrusive Suite 120 A.5.3.1 Field Relationships 120 A.5.3.2 Petrology 121 A.5.3.3 Alteration,