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THE PARAGENETIC RELATIONSHIP of EPIDOTE-QUARTZ HYDROTHERMAL ALTERATION WITHIN the NORANDA VOLCANIC COMPLEX, QUEBEC R' the PARAGENETIC RELATIONSHIPS of EPIDOTE-QUARTZ

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THE PARAGENETIC RELATIONSHIP of EPIDOTE-QUARTZ HYDROTHERMAL ALTERATION WITHIN the NORANDA VOLCANIC COMPLEX, QUEBEC R' the PARAGENETIC RELATIONSHIPS of EPIDOTE-QUARTZ TH 1848 THE PARAGENETIC RELATIONSHIP OF EPIDOTE-QUARTZ HYDROTHERMAL ALTERATION WITHIN THE NORANDA VOLCANIC COMPLEX, QUEBEC r' THE PARAGENETIC RELATIONSHIPS OF EPIDOTE-QUARTZ HYDROTHERMAL ALTERATION WITHIN THE NORANDA VOLCANIC COMPLEX, QUEBEC Frank Santaguida (B.Sc., M.Sc.) Thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Earth Sciences Carleton University Ottawa, Ontario, Canada May, 1999 Copyright © 1999, Frank Santaguida i The undersigned hereby recommend to the Faculty of Graduate Studies and Research acceptance of the thesis, THE PARAGENETIC RELATIONSHIPS OF EPIDOTE-QUARTZ HYDROTHERMAL ALTERATION WITHIN THE NORANDA VOLCANIC COMPLEX, QUEBEC submitted by Frank Santaguida (B.Sc., M.Sc.) in partial fulfillment of the requirements for the degree of Doctor of Philosophy ,n. cGJI, Chairman, Department of Earth Sciences \ NW Thesis Supervisor /4, ad,/ External Examiner ii ABSTRACT Epidote-quartz alteration is conspicuous throughout the central Noranda Volcanic Complex, but its relationship to the Volcanic-Hosted Massive Sulphide (VHMS) deposits is relatively unknown. A continuum of alteration textures exist that reflect epidote abundance as well as alteration intensity. The strongest epidote-quartz alteration phase is represented by small discrete "patches" of complete groundmass replacement that are concentrated in discrete zones. The largest and most intense zones are spatially contained in mafic volcanic eruptive centres, the Old Waite Paleofissure and the McDougall- Despina Eruptive Centre. Therefore, epidote-quartz alteration is regionally semi- conformable and is not restricted to the hangingwall or footwall of the VHMS deposits. Epidote-quartz alteration is absent from the alteration pipes associated with sulphide mineralization. Early formed epidote-quartz alteration was confined to the eruptive centres, but became more widespread as mafic volcanism progressed and the hydrothermal system matured. Pervasive silicification was also produced as the system matured, but is overprinted by epidote developed during the latter stages of volcanism. Widespread epidote-quartz alteration also flourished during these latter stages along permeable conformable zones, such as the Rusty Ridge formation, deep in the volcanic sequence. Large mass addition of Si, Al, Fei+, Ca, Mn, V, Cr, and Sr accompany depletion of Fee+, Mg, Na, K, Rb, Ba, and Zn in the epidote-quartz patches. Copper depletion is iii erratic. Large enrichments in Mn, V, and Cr are related to the modal abundance of epidote versus quartz in the alteration patches and highlight the areas of strong alteration. Background alteration prior to epidotization sufficiently enriched hydrothermal fluids in whole-rock components that produced the alteration patches. Fluid:rock ratios of 75-100 correspond to the enrichment that produced the epidote-quartz alteration. End-member epidote-clinozoisite compositions are prominent throughout the Noranda Cauldron, even at the micron-scale. At the patch-scale, iron-rich domains in epidote correspond to siliceous zones near the wallrock contact that reflect multiple episodes of hydrothermal alteration. At the cauldron-scale, Al-rich epidote is restricted to the eruptive centres where fluid circulation and temperatures are enhanced. The metasomatic changes due to epidote-quartz alteration are related to high fluid fluxes and cannot be explained by metamorphic processes. Epidote in the Noranda Cauldron is similar to the patchy alteration described in ophiolites and may have formed at moderate fluid temperatures (220-300 °C). Epidote-quartz alteration zones in Noranda do not represent the extensive, high temperature (300-400 °C), metal depletion zones that characterize epidosites deep in ophiolite sections. The Noranda Cauldron model closely corresponds to descriptions of epidote-quartz alteration in other VHMS districts. iv ACKNOWLEDGMENTS Funding for this thesis was provided by a Canadian Mining Research Organization project grant (CAMIRO project #94E07) and an NSERC grant to Dr. David Watkinson, Dr. Mark Hannington and Dr. Harold Gibson. In-kind support was also obtained from the Geological Survey of Canada and Carleton University. The participating mineral exploration companies are thanked for their continued interest in research projects oriented towards the understanding of VHMS deposits. I have benefited greatly through discussions with company geologists who helped focus the scope of this study. Inmet Exploration Ltd. is particularly noted for their field support and open use of files and maps of the Rouyn-Noranda area. I also wish to thank Dr. Alan Galley and Dr. Ian Jonasson of the GSC for several exchanges of ideas on the Noranda area geology. Mr. Richard Lancaster of the GSC provided boundless support for sample management, photography, and constant cynical dialogue. The micro-analytical expertise and cutting viewpoint of Mr. Peter Jones at Carleton University was also critical to the progression of this thesis. Thanks also go to the excellent technical assistance of Mr. Chris Rogers (Newf.') and Mr. Shawn Donaldson (`Big Boy'). I am forever personally indebted to my thesis supervisors. I maintained focus during this study by their collective insight into the scope of this thesis. Dr. Harold Gibson's wealth of knowledge in the field and on the Noranda geology set high standards of accomplishment which I hoped to have achieved. Dr. Mark Hannington's tenacity to v avoid the traps of details has made this study relevant to the grander schemes of VHMS deposit models. Dr. David Watkinson's even temperament was useful as motivation during times of reckless thought. I am grateful to my family and close friends who have supported me emotionally without question. My Mom and Dad have been particularly helpful in unconsciously reminding me that life is meant to be eaten and not just experienced. Finally, I wish to thank my wife, Suzi, who gets me through all the difficult "alterations" in life. vi TABLE OF CONTENTS CHAPTER 1: INTRODUCTION 1 Purpose 1 Scope 1 CHAPTER 2: GEOLOGIC SETTING 5 Volcanic Stratigraphy 5 VHMS Mineralization 7 Regional Hydrothermal Alteration and Metamorphism 10 CHAPTER 3: METHODS 17 Regional Mapping 17 Detailed Mapping 18 Whole Rock Geochemistry 18 Mineral Chemistry 19 CHAPTER 4: HYDROTHERMAL ALTERATION MINERAL 21 ASSEMBLAGES IN THE NORANDA VOLCANIC COMPLEX Background Alteration 22 Carbonate 25 Sericite-quartz 26 Chlorite-sericite 27 Silicification 28 Epidote-quartz 30 Stratigraphic Distribution 36 Summary 40 CHAPTER 5: RELATIONSHIPS OF EPIDOTE-QUARTZ ALTERATION 52 IN THE NORANDA MINE SEQUENCE Lac Duprat South 52 Old Waite-Norbec Mines Area 58 Ansil Hill 62 Amulet F Shaft Area. 65 Amulet Upper A Area. 68 VHMS Deposits 74 Summary 79 vii TABLE OF CONTENTS CHAPTER 6: WHOLE-ROCK METASOMATIC CHANGES 98 ASSOCIATED WITH EPIDOTE-QUARTZ Mass Balance Calculation Method 100 Conserved Elements 101 Least Altered Volcanic Rock Compositions 102 Mass Balance Results 104 Background Alteration 104 Epidote-Quartz Alteration 106 Spatial Distribution of Gains/Losses (Cauldron Scale) 109 Patch-scale Mass Gains/Losses 110 Lithologic Trends 113 Absolute Mass Changes 116 Mass Additions by Hydrothermal Fluids 118 Preliminary Whole-Rock Oxygen Isotope Data 121 for Epidote-Quartz Patches Summary 124 CHAPTER 7: ZONING OF ALTERATION MINERALS 143 Fe/Al Zoning in Epidote 143 Epidote Composition in Different Textures 147 Epidote Compositions in Different Lithologies 149 The Distribution of Epidote Compositions 150 Trace Elements in Epidote 151 The Distribution of Background Chlorite Compositions 152 Summary 153 CHAPTER 8: DISCUSSION 169 Alteration versus Metamorphic Origin of Epidote 169 Development of Epidote-Quartz Alteration in the Noranda Cauldron 171 Chemical Reactions Associated with Epidote-Quartz Alteration 178 Epidote-Quartz Alteration and Regional Oxygen Isotope Patterns 182 Epidote-Quartz Alteration and the VHMS Model 186 The Noranda Cauldron Model 186 The Ophiolite-Hosted VHMS Model 192 Comaprisons Between the Models 197 CHAPTER 9: CONCLUSIONS 206 REFERENCES 210 viii LIST OF TABLES page Table 4.1. Alteration Mineral Assemblages and Textures 43 within the CNVC. Table 5.1. Summary of Detailed Map Areas 81 Table 6.1. Least Altered Compositions of Andesitic Rocks 126 in the CNVC. Table 6.2. Summary of Mass Balance Results 129 Table 6.3. Absolute Mass Changes in the Rusty Ridge Formation 130 Table 6.4. Data for Water:Rock Ratio Calculations 131 Table 6.5. Preliminary Whole Rock Oxygen Isotope Data for 132 Epidote-Quartz Alteration Patches. Table 8.1. Chemical Reactions Representative of Alteration 199 Mineral Paragenesis in the CNVC. ix LIST OF MAPS page The Geology of the Central Noranda Volcanic Complex in pocket LIST OF FIGURES ls' Figure 2.1. Regional geology of the Rouyn-Noranda area 12 Figure 2.2. Geology of the Noranda Volcanic Complex 13 Figure 2.3. Eruptive centres within the Noranda Cauldron 14 Figure 2.4. Structural cross-section of the Noranda Cauldron 15 and location of massive sulphide deposits. Figure 2.5. Regional hydrothermal alteration and metamorphic 16 mineral assemblages in the Blake River Group. Figure 4.1. The distribution of hydrothermal alteration, central NVC 44 Figure 4.2. Alteration mineral assemblages within the 45 Noranda Mine Sequence. Figure 5.1. Lac Duprat South area alteration map 82 Figure 5.2. Epidote-quartz alteration within
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