Cambrian Granite-Related Hydrothermal Alteration and Cu-Au Mineralisation. in the Southern Mt Read Volcanics, Western Tasmania, Australia

Transcription

1 Cambrian Granite-Related Hydrothermal Alteration and Cu-Au Mineralisation in the Southern Mt Read Volcanics, Western Tasmania, Australia William F. Wyman (MSc, BSc) Submitted in_jiiiiiwfulfillment of the requirements for the degree of Doctor of Philosophy (Geology) University of Tasmania February 2001 UNIVERSITY OF TASMANIA

2 ii THESIS STATEMENT This thesis contains the results of five years research undertaken at the Centre for Ore Deposit research, University of Tasmania, between April, 1995 and July, The author states that this thesis contains no material that has been accepted for the award of any other higher degree or graduate diploma in any tertiary institution, and to the best of the author's knowledge and belief, it does not contain any material previously published or written by another person except where due reference is made in the context of the thesis. This thesis may be made available for loan and limited copying in accordance with the Copyright Act (1968). /1)~ J?! ~ v--- William F. Wyman / Dated: Distribution List 1. University Copy 2. University Copy 3. Prof. Ross Large 4. Dr. Dave Cooke 5. AMIRA 6. Bill Wyman 7. Bill Wyman 8. Spare unbound copy

3 iii ABSTRACT, i I The Darwin Granite is located in the south central portion of the Cambrian Mt. Read Volcanic Belt in western Tasmania. It has been dated at , -21 Ma by Adams et al. (1985) and is of particular interest because of it's association with several nearby Cu-Au prospects and its apparent contemporaneous timing with respect to ore formation at the Mt. Lyell mining field. The main aims of this research are to determine the nature and origin of the Darwin Granite, its relationship to the various volcanic suites in the Mt. Read Volcanics, and its relationship to the hydrothermal alteration and copper-gold mineralisation in the district. I The Darwin Granite is a highly fractionated phanerocrystalline 1-Type magnetite series equigranular granite with Suite I characteristics as defined by Crawford et al. (1992). The main pink granite phase is intruded by smaller white leucocratic, phanerocrystalline, equigranular to porphyritic, medium to coarse-grained granodiorite and microgranite phases. GENMIX modeling of major elements and REE data supports a model that the granodiorite and microgranite formed from fractionation of the pink granite phase. Negative Nd(sooMa) values indicate the Darwin Granite was derived from partial melting of a crustal source. REE patterns and abundances in host Central Volcanic Complex (CVC) rocks have virtually identical Suite I characteristics, but REE and trace element data suggest the Darwin Granite was not comagmatic with the volcanic units and they were sourced from a magma with REE and trace element characteristics similar to the Murchison Granite. A Murchison-like parental granite has not been identified in the study area, although geochemical evidence suggests that such a granite occurs beneath the study area. Numerous small tonnage, relatively high grade copper-gold prospects are located along exposed flanks and subsurface projections of the Darwin Granite. With increasing distance from the granite, ore styles are variable from iron-oxide veins and stockworks containing pyrite and chalcopyrite ± specular-hematite ± magnetite ± tourmaline and quartz-pyrite-chalcopyrite veins, to disseminated pyrite-chalcopyrite ± covellite, to veins containing quartz, bornite, neodigenite, chalcopyrite and hematite. At the Jukes Prospect, alteration and ore related assemblages are hosted in coherent dacitic volcanics of the CVC. Mineralisation occurs as disseminated pyrite and chalcopyrite, magnetite-pyrite ± tourmaline ± scheelite veins, chalcopyrite-pyrite-magnetite veins, magnetite± chlorite hydrothermal breccias, and quartz-chalcopyrite stringers. Hydrothermal sericite, chlorite and K-feldspar alteration styles occur throughout a 15 km X 3 km zone that extends northward from the Darwin Granite to the Jukes Prospect and regional aeromagnetic data suggests that the Darwin Granite underlies the entire northerly trending belt (Leaman and Richardson, 1989; Payne, 1991; Large et al., 1996). Hydrothermal alteration zones around the Darwin Granite and Jukes Prospect represent different parts of the same hydrothermal system. Hydrofracturing and phreatic brecciation of the cupola region released magmatic-hydrothermal fluids which reacted with country rocks and resulted in a complex zoned alteration system. The inner zone is composed of intense secondary K-feldspar assemblages associated with copper mineralisation and grades outward to zones of chlorite and sericite assemblages. Accessory minerals in the K-feldspar zone include sericite, chlorite, pyrite, magnetite, and chalcopyrite. In the chlorite zone accessory sericite, pyrite, magnetite occur as well as chalcopyrite veins. Initial sericite ± chlorite alteration styles were associated with microfracture and vein formation around and above the granite.

4 Total mass changes at the Jukes Prospect were minor and typically involved replacement of one mineral with another without significant nett mass changes. In sericite altered rocks, K 2 0 gains effectively balanced A(Na GaO) depletions (from plagioclase destruction) and total mass changes were small. In K-feldspar altered rocks, K 2 0 gains were larger and were accompanied by minor Si0 2 and Fe gains, although the total mass changes were still small (av. 6.1 gms/100gms). Total mass changes in chlorite altered rocks effectively balance A(K MgO + Fe ) gains with A(Na GaO + Si0 2 ) losses. In contrast to the minor mass change at the Jukes Prospect, large mass changes occurred near the Darwin Granite. In the dacites, large gains in Si0 2 (+80 gms/100gms) accompanied smaller mass gains in Al 2 0 3, K 2 0, Ba and Sr, while depletions of Si0 2 and Al occurred in adjacent andesites. The mass changes observed are explained by invoking a magmatic hydrothermal model in which magmatic fluids exsolved from the Darwin Granite. These fluids mixed with modified seawater in reaction zones around the hotter portions of the upflow or discharge zones and K 2 0, and Fe rich alteration assemblages resulted. Monomineralic vein phases suggest that close to the center of the hydrothermal system fluids were buffered by water (high volume, water/rock ratio). Farther from the systems centre, polymineralic veins and alteration styles suggest rock buffering due to lower water/rock ratios. The widespread occurrence of tourmaline throughout the Jukes-Darwin area suggests significant B in the mineralising fluids. Boron, in addition to H 2 0, may have depressed the solidus temperature of the Darwin Granite allowing the ascending granite additional time for cooling and intrusion to a higher crustal level (and a lower lithostatic pressure regime) than otherwise may have occurred. The higher level of intrusion allowed the granite to reach a level at which second boiling occurred releasing enough mechanical energy to fracture host rocks at depths of 4-5 km (Burnham and Ohmoto, 1980; Burnham, 1985) consistent with estimated depths of emplacement at Mt Darwin. Whole rock o 18 0 data for the Darwin Granite is consistent with crystallisation from a magma with o 18 0 values between 9%o and 10.5%o. Magmatic fluids in equilibrium with the granite had o 18 0 values around 9 ± 1o/oo. Limited quartz and K-feldspar data suggest that they formed from the same fluid at "C, -60"C and o 18 0fluid value of -6 ± 1%o. Magnetite o 18 0 values are 6 to 7.5 ± 1%o at temperatures of "C. Quartz, K-feldspar and magnetite probably formed from nearly pure magmatic fluids, the likely source of which was the Darwin Granite. Sulfur isotopes in the Jukes-Darwin system suggests that the initial sulfur budget was dominated by magmatic sulfur (o 34 S = 6%o) and volcanic rock sulfur (o 34 S = %o) and the seawater contribution was small (<25%). As the hydrothermal system developed, the contribution of rock sulfur and magmatic sulfur decreased and the contribution of reduced seawater sulfate increased, consistent with the arguments of Solomon et al. (1988). o 34 S values (average 7%o) from the Prince Lyell Cu-Au deposit at Mt. Lyell are interpreted to represent magmatic values but are not uniquely definitive of a genetic source of sulfur. Based on o 34 S values, either Suite II andesites (Crawford et al., 1992) or Cambrian granites could have provided the magmatic sulfur in the Mt. Lyell pyritechalcopyrite ores. REE patterns for the Prince Lyell Suite II andesites and Suite I Murchison diorite and granodiorite are nearly identical to REE patterns in apatite at Prince Lyell and the Garfield Cu-Au Prospect. iv

5 v However, apatite t:.nd(soomal values from the two prospects are different and are strong evidence that the Prince Lyell and Garfield apatites were derived from different source rocks. The Prince Lyell apatite t:.nd 1500 maj values suggest that the apatites were derived from a primitive Suite I diorite or granodiorite precursor with a crustal signature similar to the Darwin and Murchison Granites. This evidence, combined with similar REE patterns, support the interpretation that magmatic fluids derived from a Suite I granite were directly responsible for apatite-magnetite ores at Prince Lyell. Although the magnetite-apatite was almost certainly derived from a Suite I granite precursor, the source granite is either too deep to be geophysically detectable or the fluids migrated from the east, probably along the Great Lyell Fault.

6 vi ACKNOWLEDGMENTS I First and foremost my most sincere thanks to my wife Tina and my sons, Daniel and Joe. They have survived five years of my moodiness, absence and 'personal growth', while providing me with unwavering love and support. To them I am profoundly grateful. Secondly, I thank my parents Dick and Anne, without whose encouragement and financial support, this thesis would not have been possible. I am greatly indebted to my supervisors, Ross Large and Dave Cooke for their encouragement, patience and direction over the course of this project. In addition, thank you to Mike Solomon for reviews of Chapters S-7, Gary Davidson for reviewing Chapters 8 and 9," Rick Varne for his unselfish and most welcome review of Chapter 3, Tony Crawford for reviewing my REE interpretations and to Ron Berry, Bruce Gemmell and Clive Surrett for discussions and suggestions that have helped to guide this research. Thank you to Peter McGoldrick for taking me under his wing early in my stay and introducing me to volleyball. I would also like to extend my thanks to the support staff at the Centre for Ore Deposit Research and the Geology Department for their assistance and advice, especially to Peter Cornish, Simon Stephens, Christine Higgens, Marilyn Feast, Nilar Hlaing, Katie McGoldrick, Di Steffens, Jessica Tyler, Lyn Starr, 1\lathan Duhig and Andrew Jones. Thank you to Dave Steele for his guidance and assistance concerning the Electron Microprobe. A special thanks to June Pongratz for helping me with my computer frustrations and to Mike Blake and Wally Herrmann for stepping out of the mold and talking about more stimulating subjects in the tea room than footy. This research was supported by the Australian Mineral Industries Research Association Limited (AMIRA) Project P439 (Studies of VHMS related alteration: geochemical and mineralogical vectors to mineralisation). P439 was sponsored by: Aberfoyle Resources Limited, Copper Mines of Tasmania, Denehurst Limited, Mineral Resources Tasmania, Normandy Exploration, Pasminco Exploration, Queensland Metals Corporation Limited, RGC Exploration and Rio Tinto Exploration. Additional logistic support and helicopter access to the more remote areas was received from RGC Exploration and I would specifically like to thank Scott Halley, Kim Denwar, Mike Vicary, Bruce and Chopper for their help. I am also grateful to the Kevin Wills and Will Godsall from Copper Mines of Tasmania, who gave me several surface tours of the Mt. Lyell lease and underground tours of the Prince Lyell mine as well as unrestricted access to their data base and core. And finally, thank you to my office mates and fellow students, Ali Raos, Catherine Reid, Steve Hunns, Russell Fulton, Cathryn Gifkins, Andrew Rae and Bruce Anderson. You have made it all bearable and I wish you all the best. Cheers

7 vii TABLE OF CONTENTS Title Page i Statement... ii Abstract...iii Acknowledgments... vi Table of Contents... vii List of Figures xiii List of Tables... xvii List of Plates xviii 1.0 INTRODUCTION 1.1 PREAMBLE AIMS LOCATION AND ACCESS PREVIOUS WORK WORK PLAN Sampling and Sample Numbers ORGANISATION OF THESIS REGIONAL GEOLOGY, STRUCTURAL SETTING AND MINERALISATION OF THE SOUTHERN MT. READ VOLCANIC BELT 2.1 INTRODUCTION REGIONAL SETTING Regional Geology of the Southern Mt. Read Volcanics in the Mt. Darwin-Mt. Lyell Area THE WESTERN VOLCANO-SEDIMENTARY SEQUENCE CENTRAL VOLCANIC COMPLEX (CVC) EASTERN QUARTZ-PHYRIC SEQUENCE TYNDALL GROUP AND CORRELATES DARWIN GRANITE ANDESITIC-BASAL TIC VOLCANICS CAMBRIAN AND ORDOVICIAN RELATIONSHIPS Structure of the Southern Mt. Read Volcanics STRUCTURAL SETTING STRUCTURE OF THE MT. DARWIN-MT LYELL AREA Geochronology TECTONIC MODELS FOR THE MT. READ VOLCANICS GEOLOGY AND MINERALISATION IN THE MT. LYELL FIELD Geology of the Mt. Lyell Field Hydrothermal Alteration Ore Styles Genesis of the Mt. Lyell Ore Deposits Lead Isotopes at Mt. Lyell OTHER CAMBRIAN GRANITE-RELATED Cu-Au PROSPECTS IN THE MRV PETROGRAPHY AND GEOCHEMISTRY OF CAMBRIAN GRANITES IN WESTERN TASMANIA 3.1 INTRODUCTION MORPHOLOGY AND PETROLOGY OF THE DARWIN, MURCHISON AND ELLIOTT BAY GRANITES Cambrian Granite Field Relationships, Residual Gravity and Aeromagnetic Data SURFACE AND SUBSURFACE FEATURES OF THE MURCHISON GRANITE DARWIN GRANITE SURFACE AND SUBSURFACE MORPHOLOGY ELLIOTT BAY GRANITE SURFACE AND SUBSURFACE INTERPRETATIONS Petrography of the Murchison, Darwin and Elliott Bay Granites PETROLOGY OF THE MURCHISON GRANITE PETROLOGY OF THE DARWIN GRANITE, FOUR PHASES Pink Granite White granite Quartz-Feldspar Porphyry Microgranite Dykes Classification of Granites by Modal Mineralogy Summary PETROGRAPHY AND GEOCHEMISTRY OF CAMBRIAN VOLCANIC ROCKS IN THE JUKES DARWIN AREA 4.1 INTRODUCTION PHYSICAL CHARACTERISTICS (NATURE) OF THE CAMBRIAN VOLCANIC ROCKS Yolande River Sequence Central Volcanic Complex Eastern Quartz-Phyric Sequence Tyndall Group PETROLOGY OF THE CAMBRIAN VOLCANIC ROCKS Yolande River Sequence... 49

8 FINE TO MEDIUM-GRAINED QUARTZ-FELDSPAR-PHYRIC LAVA FINE TO MEDIUM-GRAINED QUARTZ-FELDSPAR-PHYRIC VOLCANICLASTIC SANDSTONE SILTSTONES AND MUDSTONES SHALE ANDESITES Central Volcanic Complex FELDSPAR-PHYRIC LA VAS AND Sl LLS QUARTZ-FELDSPAR-PHYRIC VOLCANICLASTICS AND MASS-FLOW DEPOSITS Tuffaceous-Ash/Sandstone Facies QUARTZ-FELDSPAR ± BIOTITE PORPHYRY DYKES Quartz± Feldspar Biotite Porphyry Dykes: Type Quartz-Feldspar Biotite-Porphyry Dykes: Type Eastern Quartz-Phyric Sequence QUARTZ-FELDSPAR-PHYRIC VOLCANICLASTICS AND MASS-FLOW DEPOSITS Quartz-Feldspar-Phyric Rhyolite Quartz-Feldspar-Phyric Dacite QUARTZ-FELDSPAR-PHYRIC DACITE PORPHYRY Quartz-Feldspar-Phyric Dacite VOLCANICLASTIC SANDSTONE Tyndall Group Correlates VOLCANIC ROCK GEOCHEMISTRY Constraints on the Data Major Element Geochemistry Summary Trace Element Geochemistry... 82, Summary Classification of Volcanic Rocks in the Study Area Rare Earth Element Geochemistry SUMMARY ALTERATION STYLES, MINERAL ASSEMBLAGES, TEXTURES AND ZONING IN THE STUDY AREA 5.1 INTRODUCTION PETROGRAPHIC DESCRIPTIONS OF ALTERATION FEATURES IN THE STUDY AREA Alteration Features in the YRS QUARTZ-FELDSPAR-PHYRIC VOLCANICLASTICS AND LAVAS SANDSTONE Alteration Features in the CVC QUARTZ-FELDSPAR-PHYRIC VOLCANICLASTICS Tuffaceous-Ash/Sandstone Facies FELDSPAR-PHYRIC DACITE QUARTZ-FELDSPAR± BIOTITE PORPHYRY DYKES Alteration Features in the EQPS Alteration Features in the Darwin Granite ALTERATION FEATURES IN PINK GRANITE ALTERATION IN THE WHITE GRANITE ALTERATION IN THE QUARTZ-FELDSPAR PORPHYRY ALTERATION IN THE MICROGRANITE TEXTURAL AND PETROGRAPHIC CHARACTERISTICS OF REGIONAL DIAGENESIS AND METAMORPHISM Diagenesis and Low-Grade Burial Metamorphism DIAGENETIC ALTERATION CHARACTERISTICS OF VOLCANIC ROCKS, A REVIEW CHARACTERISTICS OF LOW GRADE BURIAL MET AMORPHISM OF VOLCANIC ROCKS, A REVIEW Regional Diagenetic and Metamorphic Alteration Styles and Textures in the Study Area NTERPRETATION OF ALTERATION FEATURES IN THE JUKES-DARWIN AREA Diagenetic and Metamorphic Features in the YRS Diagenetic and Metamorphic Features in the CVC Diagenetic and Metamorphic Features in the EQPS Effects of the NNW Devonian Dynamic Metamorphic Event on Volcanic Rocks of the Study Area Summary TEXTURAL AND PETROGRAPHIC CHARACTERISTICS OF GRANITE-RELATED HYDROTHERMAL ALTERATION Hydrothermal Alteration Styles in Volcanic Rocks in the Study Area SERICITIC-DOMINATED HYDROTHERMAL ALTERATION IN VOLCANIC ROCKS CHLORITE-DOMINATED HYDROTHERMAL ALTERATION IN VOLCANIC ROCKS K-FELDSPAR-DOMINATED HYDROTHERMAL ALTERATION IN VOLCANIC ROCKS HYDROTHERMAL SILICA ALTERATION IN VOLCANIC ROCKS Hydrothermal Alteration in the Darwin Granite HYDROTHERMAL ALTERATION IN THE PINK GRANITE HYDROTHERMAL ALTERATION IN THE WHITE GRANITE viii

9 HYDROTHERMAL ALTERATION IN THE QUARTZ-FELDSPAR PORPHYRY HYDROTHERMAL ALTERATION IN THE MICROGRANITE Hydrothermal Alteration in Volcanic Rocks HYDROTHERMAL ALTERATION IN THE YOLANDE RIVER SEQUENCE HYDROTHERMAL ALTERATION IN THE CENTRAL VOLCANIC COMPLEX Feldspar-Phyric Dacite Quartz-Feldspar-Phyric Volcaniclastics Quartz Feldspar ± Biotite Porphyry Dykes Other Alteration Styles Garfield Andesites ZONATION OF GRANITE-RELATED HYDROTHERMAL ALTERATION STYLES Zonation Around the Darwin Granite Alteration Zones Along Jukes Road DISCUSSION THE GEOCHEMISTRY OF HYDROTHERMAL ALTERATION IN ROCKS OF THE JUKES-DARWIN AREA 6.1 INTRODUCTION GEOCHEMISTRY OF THE CAMBRIAN GRANITES IN THE SOUTHERN MT. READ VOLCANICS Sampling and Analytical Methods Major, Trace and Rare Earth Elements Immobile Elements Immobile Elements within the Granites Classification of Granites Classification of Granites by Molar Ratio Classification of Granites by Tectonic Setting and Source Rock Rare Earth Element Geochemistry Immobility of REE Model Partial Melting and Fractional Crystallization Comparison of the Cambrian Granites with the Devonian Granites of Western Tasmania ALTERATION MINERAL CHEMISTRY IN VOLCANIC ROCKS Chlorite PIMA Analyses of Sericite and Chlorite Apatite Carbonate MASS CHANGES IN THE JUKES-DARWIN AREA MASS CHANGE TRENDS IN RELATION TO HYDROTHERMAL ALTERATION STYLES ALTERATION REACTIONS Replacement of Feldspars by Sericite Chlorite Replacement of Feldspars and Ferromagnesian Minerals Secondary K-feldspar Deposition Secondary Quartz Deposition Replacement Reactions for Ferro magnesian Minerals Chalcopyrite Deposition SUMMARY OF THE GEOCHEMICAL STUDIES AT MT. LYELL ALTERATION INDICES SUMMARY MINERALISATION IN THE JUKES-DARWIN AREA 7.1 INTRODUCTION VEIN STYLES AND MINERAL ASSEMBLAGES QUARTZ VEINS Syn-Tectonic Quartz Veins Pre-Tectonic Quartz Veins White Quartz Veins Quartz± Tourmaline± Epidote Veins Fine-Grained Quartz Veins TOURMALINE VEINS The Significance of Boron MAGNETITE VEINS BARITE VEINS HYDROTHERMAL BRECCIAS Magnetite-Tourmaline Breccias Chlorite-Tourmaline Breccias Discussion of Breccias PARAGENE$1S Early Hydrothermal Alteration and Mineralisation... XX Middle Alteration (M1, Pre-Breccia) Hydrothermal Breccia Formation Middle Alteration (M2, Post-Breccia) Late Alteration and Mineralisation ix

10 7.5 DISCUSSION OXYGEN-DEUTERIUM ISOTOPE GEOCHEMISTRY IN THE JUKES-DARWIN AREA 8.1 INTRODUCTION MINERAL SEPARATION AND ANALYTICAL METHODS RESULTS DISCUSSION Oxygen Isotopes in the Darwin Granite Temperature and Isotopic Composition of the Hydrothermal Fluids DISCUSSION OF FLUID TEMPERATURES AND COMPOSITIONS Quartz and K-feldspar Evidence Chlorite Evidence Magnetite Evidence Water to Rock Values SUMMARY SULFUR ISOTOPES IN THE JUKES-DARWIN AREA 9.1 INTRODUCTION MINERAL SEPARATION AND ANALYTICAL METHODS RESULTS DISCUSSION Magmatic Sulfur Seawater Sulfur Formation Mechanism for 5%o to 9%o sulfide population Sulfate Compositions Heavy Sulfide Populations A REVIEW OF PREVIOUS SULFUR ISOTOPE STUDIES IN THE JUKES-DARWIN AREA AND COMPARISONS TO THE CURRENT STUDY A SUMMARY OF SULFUR AND LEAD ISOTOPES IN THE MT. LYELL FIELD A SULFUR ISOTOPE MODEL FOR THE Cu-Au ORES IN THE JUKES-DARWIN AREA SUMMARY SUMMARIES, CONCLUSIONS AND GENETIC MODEL FOR THE JUKES-DARWIN HYDROTHERMAL SYSTEM INTRODUCTION A COMPARISON OF THE JUKES-DARWIN HYDROTHERMAL SYSTEM TO MT. LYELL Alteration Assemblages and Mass Changes Geochemistry Summary and Speculation DISCUSSION OF THE CAMBRIAN GRANITE GENETIC MODEL OF LARGE ET AL. (1996) CONCLUSIONS GENETIC MODEL FOR THE DARWIN GRANITE AND ITS ASSOCIATED Cu-Au DEPOSITS Background Tectonic Setting into which the Cambrian Granites Evolved Overall Model for the Formation of Cambrian Granites and their Relationship to Associated Cu-Au Deposits: the Big Picture Detailed Genetic Model for the Jukes-Darwin System Recommendations for Further Work References... : Appendices Appendix A. Sample Descriptions and Cross-Reference.... A-1 Appendix B. Other Cambrian Granite-Related Cu-Au Prospects in the MRV... B-1 Appendix C. Geochemical Data for the Cambrian Granites of Western Tasmania... C-1 Appendix D. Normative Granite Mineralogy... D-1 Appendix E. Summary of REE Data for Cambrian Granites... E-1 Appendix E-1. Granite REE, Continued Appendix E-2. Microprobe Analytical Results for Minerals in the Darwin Granite.... E-2-1 Appendix F. Sr and Nd Data... F-1 Appendix G. Results of XRD Analyses... G-1 Appendix H. Volcanic Rock Geochemical Data... H-1 Appendix I. Feldspar Microprobe Data from the Jukes Road Appendix J. Microprobe Analytical Results for Micas from the Jukes Road.... J-1 Appendix K. PIMA spectra for rocks from the Jukes-Darwin area.... K-1 Appendix L. PIMA Data for Jukes Road and Mt. Darwin Samples... L-1 Appendix M. Summary of Carbonate Microprobe Analyses... M-1 Appendix N. Analytical Results of Vein Analyses from Mt. Darwin... N-1 Appendix 0. Alteration and Mineralisation Paragenesis: Notes and References X

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