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Reviews in Economic Volume 11

METAMORPHOSED AND METAMORPHOGENIC DEPOSITS

CONTENTS

Ores and : Introduction and Historical Perspectives F.M. Vokes Regional Metamorphic Remobilization: B. Marshall, F.M. Vokes, and A.C.L. Larocque Upgrading and Formation of Ore Deposits Discriminating between Regional Metamorphic Remobilization and B. Marshall and P.G. Spry Syntectonic Emplacement in the Genesis of Massive Metamorphic Fluids and Their Relationship to the Formation of I. Cartwright and N.H.S. Oliver Metamorphosed and Metamorphogenic Ore Deposits Regional Metamorphism and Ore Formation: C.A. Heinrich, A.S. Andrew, and M.D. Knill Evidence from Stable Isotopes and Other Fluid Tracers Fiuid Inclusions in Metamorphosed and Synmetamorphic B. Marshall, A.D. Giles, and S.G. Hagemann (Including Metamorphogenic) Base and Precious Metal Deposits: Indicators of Ore-FormingConditions and/ or Ore-Modifying Histories? Sulfidation and Oxidation Haloes as Guides in the P.G. Spry Exploration for Metamorphosed Massive Sulfide Ores Meta-Exhalites as Exploration Guides to Ore P.G. Spry, J.M. Peter, and J.F. Slack Metamorphism of -Hosted Sulfide Deposits S.J. Barnes and R.E.T. Hill Metamorphism of Ni-Cu in Mafic-Ultramafic Intrusions: F. Mancini and H. Papunen The Svecofennian Saaksjarvi Complex, Southern Finland Mineralization and Metamorphic Remobilization in R. Höll and R. Eichhorn the Felbertal Deposit, Central , Austria Gold Deposits in Amphibolite and Granulite Terranes J. Ridley, D.I. Groves, and J.T. Knight of the Archean Yilgarn Craton, Western Australia: Evidence and Implications of Synmetamorphic Mineralization Subduction-Related Deposits? Constraints, W.L. Griffin, S.Y. O’Reilly, and R.M. Davies Possibilities, and New Data from Eastern Australia

Editors F.M. Vokes, B. Marshall, and P.G. Spry

SOCIETY OF ECONOMIC , INC. Society of Economic Geologists, Inc.

Reviews in , Vol. 11 Metamorphic and Metamorphogenic Ore Deposits F.M. Vokes, B. Marshall, and P.G. Spry, Editors

Additional copies of this publication can be obtained from

Society of Economic Geologists, Inc. 7811 Shaffer Parkway Littleton, CO 80127 www.segweb.org

ISBN: 978-1-629495-69-9 The Authors:

Anita Andrew Alan D. Giles Robin E.T. Hill CSIRO Division of Petroleum Dewrtment of Applied Geology CSIRO, Exploration and Mining Resources University of Technology- Sydney Private Bag, PO Wembley PO Box 136 North Ryde PO Box 123 Broadway Western Australia 6014 New South Wales 1670 New South Wales 2007 Australia Australia Australia Tel. +61.8.9333.6373 Tel. +6.2.9490.8743 .TeL +61.2.6287.3681 Fax: +61.8.9383.7993 Fax: +61.2.9490.8921 Fax: +61.2.6288.2876 e-mail: [email protected] e-mail: [email protected] e-mail: [email protected] Rudolf HoB Stephen J. Barnes William L. Griffin Institut fiir Allgemeine und CSIRO Division of Exploration GEMOC Angewandte Geologie and Mining Department of Earth and Planetary Ludwig-Maximillians-Universiilit Private Bag, W~mbley Sciences Luisenstrasse 37 Western Australia 6014 Macquarie University D-80333 Miinchen Australia Sydney . Germany Tel. +61.8.9333.6375 New South Wales 2109 Tel. +49.89.5203.214 Fax: +61.8.9383.7993 Australia Fax: +49.89.5203.293 e-mail: [email protected] Tel. +61.2. 9850.8954 e-mail: rudolf.hoell@ Fax: +61.2.9850.8943 iaag.geo.unimuenchen.de Ian Cartwright e-mail: [email protected] Department of Earth Sciences Matthias D. Knill Monash University David I. Groves SIG Schweizerische Industrie- Clayton Centre for Strategic Deposits Gesellschaft Holding AG Victoria 3168 University of Western Australia Industrieplatz Australia Nedlands 8212 Neuhausen am Rheinfall Tel. +61.3.9905.4887 Western Australia 6907 Switzerland Fax: +61.3.9905.4903 Australia Tel. +41.52.674.6123 e-mail: [email protected] Tel. +61.8.9380.2685 Fax: +41.52.674.6556 Fax: +61.8.9380.1178 e-mail: [email protected] Rondi M. Davies e-mail: dgroves®geol. uwa.edu.au GEMOC Joseph T. Knight Department of Earth and Planetary Steffen G. Hagemann BHP Discovery Sciences Department of Geology and Level 3, QCL House Macquarie University 40 McDougall St. Sydney Centre for Strategic Mineral Deposits Milton, Brisbane New South Wales 2109 University of Western Australia Queensland 4064 Australia Nedlands Australia Tel. +61.2.9850.8258 Western Australia 6907 Tel. +61.7.3307.9600 Fax: +61.2.9850.6904 Australia Fax: +61.7.3307.9500 e-mail: [email protected] Tel. +61.8.9380.1517 e-mail: [email protected] Fax: +61.8.9380.1178 Roland Eichhorn e-mail: shageman@geol. uwa.edu.au Adrienne C.L. Larocque Bayerisches Geologisches Landesamt Department of Geological Sciences HeBstrasse 128 Christoph A. Heinrich 125 Dysart Road D-80797 Miinchen Institut fiir Isotopengeologie und University of Manitoba Germany Mineralische Rohstoffe Winnipeg, Manitoba R3T 2N2 Tel. +49.841.9511.139 Departement Erdwissenschaften NO Canada Fax: +49.89.1213.2647 ETH Zentrum Tel. +1.204.474.7413 e-mail: [email protected] CH-8092 Zurich Fax: +1.204.474.7623 Switzerland e-mail: [email protected] Tel. + 41.1.632.6851 Fax: +41.1.632.1179 e-mail: [email protected]

ii Franco Mancini Jan M. Peter Mineral and Fuel Resources of Canada Department 601 Booth Street Geological Survey ofJapan Ottawa, Ontario KIA OE8 1-1-3 Higashi, Tsukuba 305 Canada Japan Tel. +1.613.992.2376 Tel. +81.298.543627 Fax: +1.613.996.9820 Fax: +81.298.543633 e-mail: [email protected] e-mail: [email protected] John Ridley Brian Marshall GEMOC Department of Applied Geology Department of Earth and Planetary University of Technology- Sydney Sciences PO Box 123 Broadway Macquarie University New South Wales 2007 Sydney Australia New South Wales 2109 Tel. +61.2.9514.1775 Australia Fax: +61.2.9514.1755 Tel. +61.2.9850.8371 e-mail: [email protected] Fax: +61.2.9850.8943 e-mail: [email protected] Nicholas H.S. Oliver Economic Geology Research Unit John F. Slack School of Earth Sciences U.S. Geological Survey James Cook University National Center, MS 954 Townsville Reston, VA 20192 Queensland 4811 USA Australia Tel. +1.703.648.6337 Tel. +61.7.4781.5049 Fax: +1.703.648.6383 Fax: +61.7.4725.1501 e-mail: [email protected] e-mail: [email protected] Paul G. Spry Suzanne Y O'Reilly Department of Geological and GEMOC Atmospheric Sciences Department of Earth and Planetary 253 Science I Sciences Iowa State University Macquarie University Ames, lA 50011-3212 Sydney USA New South Wales 2109 Tel. +1.515.294.1837 Australia Fax: +1.515.294.6049 Tel. +61.2.9850.8258 e-mail: [email protected] Fax: +61.2.9850.6904 e-mail: [email protected] Frank M. Vokes Institutt for Geologi og Bergteknikk Heikki Papunen Norges tekniske naturvitenskapelige Department of Geology Universitet University ofTurku N-7034 Trondheim FIN-20014 Norway ,, Turku Tel. +47.7359.4808 ,. Finland Fax: +47.7359.4814 Tel. +358.2.333.5480 e-mail: [email protected] Fax: +358.2-333.6580 e-mail: [email protected]

iii PREFACE

Many of the world's largest deposits of base and precious thors are followed by Heinrich, Andrew, and Knill, who use metal ores are located in metamorphic terclnes. Deforma­ mass-balance and metal- arguments to constrain tion, metamorphism, and the accompanying fluid-flow metamorphogenesis, before discussing the contributions regimes have tremendous capacity to both form and modifY of stable isotopes and other fluid tracers in studies of meta­ such deposits. Nevertheless, ideas regarding-the relationships morphic ore formation. Marshall, Giles, and Hagemann of specific deposits to metamorphic and_ deformational close the section on fluids by focusing on the application of processes affecting their host rocks have varied over the years; fluid-inclusion studies to determine the genesis and fluid once again, these relationships and associated concepts are history of metamorphosed-metamorphogenic deposits. being scrutinized and intensely questioned. It is, therefore, Exploring for and assessing ore deposits in metamorphic an appropriate time to review knowledge and beliefs per­ terranes are facilitated by the recognition of a range of taining to several aspects of these ores. Not only is such a re­ lithologic-mineralogic guides that result from metamor­ view ofacademic interest (important and exciting as this may phism of preexisting ores and their associated host rocks. be), but also, a better understanding of the timing of miner­ These ore indicators have district-wide and more local sig­ alization relative to deformation, metamorphism, and re­ nificance for exploration. Spry reviews exploration guides gional and local fluid flow is essential to more effective ex­ provided by the mineralogical changes produced by sulfi­ ploration for, and exploitation of, these types of ore. dation and oxidation processes in the vicinity of sulfide It has not been practical to cover all aspects of ores in ores; Spry, Peter, and Slack evaluate the use of characteris­ metamorphic terranes in this volume. The individual pa­ tic horizons of metamorphosed exhalites as guides to the pers are authoritative, being based on the original research presence of possible economic, exhalative ores. of well-recognized experts in their respective fields, and in The remaining five papers are devoted to aspects of a se­ many cases they present new data. While a degree of bal­ lected number of ore types found in metamorphic ter­ ance has been sought, it is recognized that some important ranes. Two papers deal with the metamorphism ofNi-(Cu) ore types and related processes lack consideration. This is ores of magmatic affiliation found in Precambrian rocks: undoubtedly the case for some nonsulfidic ore types, and Barnes and Hill review the metamorphism of komatiitic with one exception, most nonmetallic mineral deposits in volcanic-hosted Ni ores in Archean terranes, and Mancini metamorphic terranes. Furthermore, contact metamor­ and Papunen consider Ni-Cu ores associated with Pro­ phic ores have received no attention because their ore-gen­ terozoic mafic-ultramafic intrusions in the Fennoscandian erating events are predominantly magmatic-hydrothermal shield. Holl and Eichhorn present a reassessment of the (rather than regional metamorphic), and in any case, such metamorphic development of the Felbertal scheelite de­ ores would warrant a whole volume to do them justice. posits in the central Alps of Austria. Evidence for the meta­ The distinction between metamorphosed, metamor­ morphogenic (synmetamorphic) origin of important Au phic, and metamorphogenic mineral deposits is ad­ deposits in high-grade metamorphic terranes in the dressed, and the terms defined, in an introductory chap­ Archean Yilgarn craton of Australia is discussed by Ridley, ter by Vokes that also reviews the historical development of Groves, and Knight. The final paper, by Griffin, O'Reilly, ideas on ores in metamorphic terranes. Aspects of this ter­ and Davies, deals with the possibility of subduction-related minology have also been developed in several other pa­ diamond deposits, this being the only nonmetallic ore pers (e.g., Marshall, Vokes, and Larocque; Marshall and type considered in the volume. Spry; and Heinrich, Andrew, and Knill). It is apparent that Throughout the volume, the spelling "terrane" has been some see metamorphogenic as a subset of syntectonic-syn­ used, regardless of whether it relates to, for example, are­ metamorphic, whereas others apply it to any deposit gion of high-grade metamorphism or a geotectonic entity. formed during metamorphism, irrespective of the nature Where the use is not obvious from the context, clarifica­ of the transporting fluid. tion is provided by way of a footnote. The currently most contentious aspect of ores in meta­ Reviews in Economic Geology volumes have in the past, with morphic terranes is the distinction between metamor­ one exception, been produced in connection with a Soci­ phosed-remobilized preexisting deposits and those thought ety of Economic Geologists Short Course devoted to the to have been formed by metamorphic-deformational theme of each volume. T his is not the case with the pre­ events. Marshall, Vokes, and Larocque review the possible sent volume, principally because of the difficulty in bring­ roles of metamorphic remobilization in the upgrading of ing together such a widely distributed set of authors. We existing deposits and the formation of new ones, while Mar­ nevertheless hope that the volume will provide an up-to­ shall and Spry thoroughly review the problem of metamor­ date and relatively comprehensive coverage of the rela­ phosed versus metamorphogenic ores, present guidelines tionships between metamorphism-deformation and fluid to aid in discriminating between these ores, and apply their flow, and the formation and modification of metallic min­ guidelines to a range of major ore deposits. eral deposits. The generation of metamorphic fluids, the magnitude and complexity of fluid-flow regimes, and the all-important Frank M. Vokes role of these fluids in modifying existing ores and forming Brian Marshall new ones are covered by Cartwright and Oliver. These au- Paul G. Spry

iv BIOGRAPHIES ANITA S. ANDREW received her B.Sc. (Hons.) and Ph.D. monds from a number of localities. She also has carried degrees from the University of Sydney, with thesis study ad­ out similar studies of from Myanmar, Thailand, dressing the scale of fluid movement during metamor­ and the Slave craton of Canada. phism. Mter holding a postdoctoral position at Virginia Polytechnic Institute and State University, she joined Com­ ROlAND EICHHORN is a graduate ofLudwig-Maximilians monwealth Scientific and Industrial Research Organisa­ University of Munich, Germany, where he obtained a tion (CSIRO) as a Research in 1982. There she Diplom degree in geology in 1991 and a Ph.D. degree in applied isotopic techniques to problems of 1995. He was guest scientist at several renowned isotope and mineral exploration. In 1993, she moved to the newly laboratories, such as the Max-Planck Institut for formed Division of Petroleum Resources at CSIRO, re­ in Mainz (Germany), the Institute de Physique de Globe in searching problems related to petroleum exploration; in Paris (France) and the SHRIMP II laboratory of Curtin particular, she worked on developing new isotopic tech­ University (Western Australia). Research interests have fo­ niques for inter- and intrabasinal correlations. Currently, cused on isotopic and g~ochronologic aspects of ore-form­ Andrew the CSIRO Petroleum Exploration and Ap­ ing processes of tungsten deposits, especially in areas of praisal research program. She is an author of more than multistage metamorphosed complexes. He is now employed 90 scientific and technical publications. by the Geological Survey of Bavaria (Germany), currently working on a statewide geotope mapping, evaluation, and STEVEN BARNES is a research scientist at the CSIRO Di­ protection program and as a specialist for geologic GIS map vision of Exploration and Mining in Perth, Western Aus­ publications via internet and on CD-ROMs. tralia. He completed his B.A. degree in and Petrology at Cambridge University in 1977. Mterward, he ALAN D. GILES is the Senior Technical Officer in the De­ earned M.Sc. (1979) and Ph.D. (1983) degrees from the partment of Applied Geology, University of Technology, University of Toronto, with master's work focusing on the Sydney. He received the degree of B.App.Sc. (Hons.) from Katiniq nickel sulfide deposit, and doctoral work on plat­ the New South Wales Institute of Technology (NSWIT), in inum reef mineralization in the ·Stillwater Complex. He 1983. Following a short period in metalliferous explo­ then spent two years as a postdoctoral fellow in experi­ ration, he joined the University of Technology (formerly mental petrology at the NASA:Johnson Space Center in the NSWIT), where he has particularly concentrated on Houston. Barnes has been a member of the CSIRO Mag­ technology pertinent to deformed and metamorphosed matic Ore Deposits team since 1985, with an intervening ore deposits. His research publications and nearly com­ spell as exploration for Hunter Re­ pleted Ph.D. involve fluid-inclusion studies on massive-sul­ sources Ltd., from 1988 to 1990. His research interests in­ fide ore deposits in metamorphic terranes. However, he clude genesis of magmatic sulfide ore deposits, petrogen­ also has undertaken consulting work for industry on in­ esis of , petrogenesis and tectonic setting of clusion systems in topaz, sapphire, , petroleum, ep­ Archean greenstone terranes, of ithermal gold, and porphyry style deposits. and , geochemistry and metallogenesis of plat­ inum group elements, and fluid- interactions in ultra­ WllLIAM L. GRIFFIN is a Chief Research Scientist of the mafic rocks. CSIRO and an adjunct professor at Macquarie University. He has spent most of his research career studying high­ IAN CAR'IWRIGHT is currently Senior Lecturer in pressure metamorphic rocks in both the and mantle, crustal fluid flow at the Department of Earth Sciences, using petrology, major and trace element geochemistry, Monash University, Australia. He received his B.S. degree and isotopic techniques. Since 1986, a large 'part of this ef­ from the University College of Wales, U.K., in 1982, and fort has been directed toward all aspects of the distribu­ his Ph.D. from the same institution in 1986. Prior to arriv­ tion of diamond in the lithosphere, including both dia­ ing at Monash in 1990, he was a research fellow at the Uni­ mond genesis and diamond exploration. versity of Wisconsin, Madison. His research interests en­ compass fluid flow in a range of geologic environments, DAVID GROVES is Professor of Economic Geology and including metamorphic, ore-forming, and hydrogeologic Director of ~.the Centre for Strategic Mineral Deposits systems. Most of his research involves the application of within the Department of Geology and Geophysics, Uni­ petrology, stable isotopes, and other geochemical tracers versity of Western Australia. He received his Ph.D. degree to constrain conditions of fluid-rock interaction, pathways from the University of Tasmania, with study focused on of fluid flow, fluid volumes, and the timing and duration -sulfide deposits, under the supervision of Mike of fluid-flow events. Solomon, and.. has since researched , nickel, -cop­ per, PGE, andlgold deposits. Currently, he leads an inte­ RONDI M. DAVIES is now completing a Ph.D. study on grated research team that is studying the genesis of ore de­ the diamonds of eastern Australia, which has included de­ posits, with special emphasis on orogenic lode gold tailed studies of morphology, internal structure, inclusion deposits, and assisting in the development of exploration chemistry, N aggregation and isotopic composition of dia- models based on deposit and genetic models. His recent

v BIOGRAPHIES (continued) research has been on the global characteristics of lode entist with CSIRO, Perth, Western Australia, working on gold deposits and the generation of worldtclass deposits the genesis of magmatic sulfide deposits associated with within the deposit style. mafic and ultramafic rocks.

STEFFEN G. HAGEMANN received a B.Sc. degree from RUDOLF HOLL is Professor of Geology at the Institute the johann-Wolfgang Goethe University in Frankfurt, Ger­ for General and Applied Geology at the University of Mu­ many, and an M.Sc. degree from the University of Wiscon­ nich. He studied economics and geology and received a sin-Milwaukee. Master's degree work involved-courses and Diplom-Volkswirt degree in economics and a Diplom-Geologe research at the UW-Madison, San Diego State University, degree in geology at the University of Munich. He earned and Universidade de Brasilia, Brazil. He obtained his his doctoral degree in geology for research of , Ph.D. in economic geology from the University of Western cinnabar, and tungsten deposits in Turkey. Projects he has Australia in 1993, working in the Key Centre for Strategic worked on include economic geology, economics in geol­ Mineral Deposits (headed by David I. Groves) within the ogy, , regional geology, mapping, and super­ Department o,f Geology and Geophysics. Subsequently, vising of mapping for the state of Bavaria. He discovered Hagemann held a National Science Foundation-spon­ the Felbertal scheelite deposit and numerous other sored postdoctoral position at the UW-Madison, with brief scheelite occurrences in central Europe. stints at the University of Toronto and the University of Saskatoon, before accepting a position as Assistant Profes­ JOSEPH T. KNIGHT earned his B.Sc. (Hons.) degree in sor at the Technical University of Munich. Currently he is geology from Nottingham University, and an M.Sc. degree a Senior Lecturer at the Centre for Strategic Mineral De­ from the Camborne School of Mines. His Ph.D. work, at posits at the University of Western Australia. Research in­ the University of Western Australia, was on the geology of terests are the structural-hydrothermal architecture and the Coolgardie Goldfield. Currently, Knight is working for processes that form orogenic gold, intrusion-hosted (oxi­ BHP Minerals Discovery as Principal Geologist based in dized) gold, volcanic-hosted massive sulfides, high-grade Brisbane, Australia. banded- formation and emerald deposits, and the re­ lationship between transcrustal tectonic zones and metal­ MATTHIAS KNILL studied economic geology and petrol­ lic ore deposits. ogy at ETH Zurich, Switzerland, and then completed a Ph.D. degree on the Lengenbach deposit in the Swiss Alps CHRISTOPH HEINRICH studied geology and petrology at the same University. This was the first modern geo­ at ETH (Zurich), completing a Ph.D. degree on high-pres­ chemical study of a small but famous deposit that had pre­ sure metamorphic petrology in the central Alps. He then viously been mainly the focus of mineralogical interest. emigrated to Australia to study economic geology at the Previously a research scientist and information officer as­ CSIRO in Sydney and worked as a research scientist at the sociated with the Swiss nuclear waste management pro­ Australian Geological Survey in Canberra until 1994, gram, NAGRA, he is now in charge of corporate commu­ when he was appointed Professor of Mineral Resources at nications at the Swiss Industrial Company Holding Ltd. the Swiss Federal Institute of Technology and the Univer­ sity of Zurich. His current research concentrates on the ADRIENNE LAROCQUE is an Assistant Professor in the chemical, thermal, and mechanical aspects of fluid trans­ Department of Geological Sciences at the University of port in the Earth's interior, to quantify the processes of hy­ Manitoba. She received her Ph.D. from Queen's University, drothermal ore formation. His ore fluids group in Zurich Ontario, in 1993. Her thesis on the topic of metamorphic combines studies with experimental and numeric remobilization in a gold-rich Archean VMS deposit was su­ model simulations, with a particular interest in metamor­ pervised by C.J. Hodgson and Louis Cabri. Adrienne made phic and magmatic-hydrothermal systems. Heinrich is a extensive use of SIMS (secondary ion mass spectrometry) board member of the Swiss Geotechnical Commission and for her doctoral work, and since then has applied SIMS in the Society for Geology Applied to Ore Deposits (SGA). other areas of geochemical research. Before taking up her He serves on the SEG Distinguished Lecturer Commission position in Manitoba, Adrienne was a Director's Postdoc­ and on the editorial board of Economic Geology. toral Fellow at Los Alamos National Laboratory. There she worked with Don Hickmott on ion implantation for stan­ ROBIN E. T. HILL graduated from the University of dardization of SIMS analyses and studied metal residence Queensland, Australia, in 1964, with the degree of Bache­ and mobility in volcanic systems with Fraser Goff. Larocque lor of Applied Science. He earned the degree of Ph.D. continues to use various microbeam techniques to study from Queen's University, Kingston, in 1968 (experimental base and precious metal mobility and accumulation in geochemistry). Since then, he has completed postdoctoral magmatic and hydrothermal systems. research, at Pennsylvania State University, on the role of carbon dioxide in mantle-derived silicate melts, was senior FRANCO MANCINI received an M.Sc. degree in Earth nickel research geologist with a mineral exploration com­ Sciences in 1989 from the University of Rome, Italy, and a pany in Canada, and since 1973 has been a research sci- Ph.D. degree in Geology and Mineralogy from the Uni-

vi BIOGRAPHIES (continued) versity ofTurku, Finland, in 1996. He has been involved in and geochemistry, and the composition, evolution, and various studies of regionally metamorphosed Ni-Cu ore thermal state of the continental lithosphere. deposits, including the effects of hydrothermal alteration and the remobilization of sulfides. His research interests HEIKKI PAPUNEN received his M.Sc. degree from also include crystal chemistry as a tool to characterize the Helsinki University (1960) and Ph.D. from University of effects of metamorphism on ore deposits. He is presently Turku, Finland ( 1971). He joined the Department of Geol­ a postdoctoral research assistant/scientist at the transmis­ ogy, University of Turku, where he is now Professor and sion electron microscope laboratory of the Geological Sur­ head of the department. He has been involved in ore geol­ vey of Japan, where the research centers on the mi­ ogy, mineralogy, and exploration-related research, particu­ crostructures in a number of minerals from regionally larly in the fields of ore deposits associated with mafic and metamorphosed Mn-Fe ores. ultramafic rocks. He has served on the editorial boards of Economic Geology and Lithos, as leader of the International BRIAN MARSHALL became adjunct Professor in Geology Geological Correlation 'Programme (IGCP) Project 161 at the University of Technology, Sydney, Australia, in 1997. (Ore deposits related to mafic and ultramafic rocks), and as He received his B.Sc. (Hons.) degree in Geology (1959) the chairman of a commission of International Association from Imperial College, London University, and his Ph.D. on the Genesis of Ore Deposits (lAGOD). He has also acted (1966) from Bristol University, U.K. He has variously as a chairman of organization committees for several sym­ worked for the Tasmanian Geological Survey (1963-1966), posia and field courses, including the 5th International for large and small companies in full-time base and pre­ Platinum (1989) and 4th Biennial SGA Meeting (1997). He cious metal exploration (1970-1974), and in a range of was elected President of SGA for 1999-2000. consulting activities (over some 30 years). Marshall's in­ termittent academic career commenced at Melbourne JAN M. PETER is an economic geologist for the Mineral University (1966-1967), continued at the University of Resources Division of the Geological Survey of Canada New South Wales (1967-1970), and recommenced in (GSC) in Ottawa. He received his B.Sc. (Hons.) degree in 1974 when he joined the New ~outh Wales Institute of Geology from the University of British Columbia in 1983 Technology (now, University of Technology) as a senior and his M.Sc. and Ph.D. degrees from the University of lecturer. Although for many years a structural geologist, Toronto in 1986 and 1991, respectively. His graduate train­ he applied the principles of this discipline in the sphere of ing focused on sea-floor hydrothermal mineralization and deformed and metamorphosed base and precious metal ancient analogues. Prior to joining the staff of the GSC in deposits. Over the past 15 years, this initial interest in the 1994, he was an Natural Sciences and Engineering Re­ imposed geometry and mechanical response of deposits search Council (NSERC) postdoctoral fellow at the GSC. has evolved into a more general consideration of fluid-re­ Peter's research has dealt with the setting and depositional lated processes of remobilization of sulfides versus their processes of modern sea-floor hydrothermal mineraliza­ host rocks, and mobilization and emplacement-site geol­ tion at the sedimented Guaymas basin and Middle Valley ogy in the context of syntectonic deposits. sites, the genesis of the Windy Craggy deposit, and genesis of hydrothermal sediments (iron formations) related to NICHOLAS OLIVER (B.Sc., Hons., University of Queens­ massive sulfide deposits of the Bathurst -zinc mining land, 1981; Ph.D., Monash University, 1988) has a wealth camp, in New Brunswick, and their application to the ex­ of field and analytical experience in appraisal of alteration ploration for concealed mineralization. systems in metamorphic rocks and ore deposits, mostly in Australia. These include studies of regional albitization, JOHN RIDLEY received his Ph.D. degree (l982) from Ed­ veining and related Cu-Au mineralization in the Mount inburgh University, where his work focused on metamor­ Isa block, greenstone-hosted Au in the Yilgarn and Pilbara phic and . Mter completing a postdoc­ cratons, Cu in the Kanmantoo district of South Australia, toral fellowship in Switzerland and a short contract with and iron in the Hamersley province of Western Australia. the Norwegian Geological Survey, he taught at the Uni­ He has published papers on mechanical constraints on versity of Zimbabwe, the University of Western Australia, fluid flow in these systems as well as a range of more geo­ and ETH, Zgrich. In Western Australia, his major research chemical-isotopic-petrologic papers. He was appointed as interest was the gold deposits of the Archean Yilgarn cra­ the W.C. Lacy Professor of Economic Geology in the ton, which are hosted in high-grade metamorphic rocks, School of Earth Sciences at james Cook University in 1997. with emphasis on the tectonic environment of these de­ posits and their structural, geochemical, and petrological SUZANNE Y. O'REILLY is Professor of Geology at Mac­ characteristics,· He was recently appointed as lecturer in quarie University and Director of the ARC National Key economic geo'togy at Macquarie University, Sydney. Centre for Geochemical Exploration and Metallogeny of Continents (GEMOC), which aims to understand the de­ PAUL G. SPRY is Professor and Chairman of the Depart­ velopment of the Earth's outer 300 km. Her research in­ ment of Geological and Atmospheric Sciences at Iowa State terests include geochemistry, xenolith petrology University in Ames, Iowa. He completed B.Sc. (Hons.), and

Vll BIOGRAPHIES (continued) M.Sc. degrees at the University of Adelaide in 1976 and ore deposits. Recently he directed a major USGS project 1978, respectively, and a Ph.D. degree at th"e University of on the Bald Mountain massive sulfide deposit in northern Toronto in 1984. Paul has conducted research on various Maine. His current research is focused on volcanogenic metamorphosed massive sulfide deposits in South Africa, and sedex-type mineral deposits in Alaska. Canada, Norway, Australia; and the United States, with a focus on the origin of meta-exhalites, sulfidation halos, and FRANK M. VOKES, Emeritus Professor of Ore Geology at mineralogical anomalies. Other research int~rests include the Norwegian University of Science and Technology, the petrologic, mineralogic, stable isotope, and fluid inclu­ Trondheim, received his undergraduate and master's sion characteristics of epithermal and mesothermal gold­ training in mining engineering and geology at Leeds Uni­ telluride deposits. Paul served on the editorial board of Eco­ versity, England, from 1945 to 1950. After working for sev­ nomic Geology from 1993 to 1998. eral years on the Zambian belt, he investigated massive cupriferous sulfide deposits in northern Norway. JOHN F. SLACK received a B.S. degree in geology from The resulting publication was the emphasis of his doctoral West Virginia University in 1970, an M.S. in geology from work at the University of Oslo (Ph.D., 1957). After docu­ Miami (Ohio) University in 1972, and a Ph.D. in economic menting deposits in Canada and massive sul­ geology from Stanford University in 1976. Since 1974 he fides on Cyprus, interspersed with teaching and research has been employed by the U.S. Geological Survey, first in at Oslo, he moved in 1966 to Trondheim, where he fur­ Menlo Park, California, and since 1976 in Reston, Virginia. ther developed his interests in massive sulfide deposits, es­ His Ph.D. research was on multistage vein ores in south­ pecially their metamorphism and deformation. From 1974 western Colorado. Early work for the U.S. Geological Sur­ to 1984, Vokes was leader of IGCP Project no. 60 on Cale­ vey involved research on Appalachian massive sulfide de­ donian strata-bound sulfides and later, chairman of the posits, concurrently with mineral-resource assessments of IAGOD working group on ores and metamorphism. He is Wilderness areas and the Glens Falls (NY-VT-NH) a past President of SGA and former Regional Vice-Presi­ CUSMAP quadrangle. A significant part of his career has dentofSEG. been devoted to the study of tourmaline in hydrothermal

viii CONTENTS Chapter 1-0res and Metamorphism: Chapter 5-Regional Metamorphism and Ore Introduction and Historical Perspectives Formation: Evidence from Stable Isotopes and Frank M. Vokes Other Fluid Tracers ABSTRACT...... I Christoph A. Heinrich, Anita S. Andrew, INTRODUCTION ...... } and Matthias D. Knill OVERVIEW OF EARLY LITERATURE ...... 2 .ABSTRACT ...... 97 AsPECTS OF PRESENT SITUATION ...... 7 INTRODUCTION ...... 97 CONCLUSIONS ...... 13 METAMORPHIC ORE FORMATION: SOME AcKNOWLEDGMENTS ...... l3 BASIC REQUIREMENTS ••.•••...•...• : ...... 98 REFERENCES ...... 13 LENGENBACH, A METAMORPHOSED, -HOSTED, BASE METAL DEPOSIT ...... ! 02 Chapter 2-Regional Metamorphic Remobilization: METAMORPHIC COPPER ORE FORMATION Upgrading and Formation of Ore Deposits AT MOUNT ISA ...... ' ...... l04 Brian Marshall, Frank M. Vokes, and Adrienne C.L. Larocque BASE METAL DEPOSITS.IN SILICATE-RICH METAMORPHIC .ABSTRACT ...... 19 ROCKS ...... l07 INTRODUCTION ...... 20 MESOTHERMAL GoLD DEPOSITS ...... ! 08 TERMINOLOGY AND CONCEPTS ...... 21 IMPLICATIONS: METAMORPHOGENIC GoLD VS. TEXTURAL AND MINERALOGICAL UPGRADING ...... 23 BASE METAL DEPOSITS ...... 112 THE COMPOSITION OF SOURCE OR . SUMMARY AND CONCLUSIONS ...... 112 PARENT MINERALIZATION ...... 23 ACKNOWLEDGMENTS ...... ll4 TRANSFER PROCESSES IN METAMORPHIC REFERENCES ...... 114 REMOBILIZATION ...... 24 MAGMATIC AND -RELATED REMOBILIZATION ...... 28 Chapter 6-Fiuid Inclusions in Metamorphosed and Syn­ EMPLACEMENT-SITE PROCESSES AND RELATIONSHIPS ...... 30 metamorphic (Including Metamorphogenic) Base and TRANSPORT RATES AND DISTANCES ...... 32 Precious Metal Deposits: Indicators of Ore-Forming CoNCLUSIONS ...... :...... 34 Conditions and/or Ore-Modifying Histories? AcKNOWLEDGMENTs ••••••.•••.•••••••••.••••••••••••••••••••.••..••.••••••••• 34 Brian Marshall, Alan D. Giles, and Steffe:n G. Hagemann REFERENCES ...... 35 .ABSTRACT ...... 119 INTRODUCTION ...... 120 Chapter 3-Discriminating between Regional FLUID INCLUSIONS, REGIONAL METAMORPHISM, Metamorphic Remobilization and Syntectonic AND LATE TECTONICS ...... 122 Emplacement in the Genesis of Massive Sulfide Ores FLUID INCLUSION CHARACTERISTICS OF Brian Marshall and Paul G. Spry MASSIVE SULFIDE DEPOSITS IN THE .ABSTRACT ...... 39 Low-TEMPERATURE REGIME ...... 127 INTRODUCTION ...... 39 FLUID INCLUSION CHARACTERISTICS OF GOLD ScoPE oF PROBLEM ...... 40 DEPOSITS IN THE HIGH P-T (INTERMEDIATE- GUIDELINES FOR SUCCESSFUL DISCRIMINATION.: ...... 49 TO HIGH-TEMPERATURE) REGIME ...... 132 SOME CONTENTIOUS EXAMPLES ...... 53 CONCLUSIONS AND IMPLICATIONS ...... l43 CONCLUSIONS ...... 72 ACKNOWLEDGMENTS ...... 144 AcKNOWLEDGMENTS ...... 73 REFERENCES ...... 144 REFERENCES ...... 73 Chapter 7-Sulfidation and Oxidation Haloes as Guides Chapter 4-Metamorphic Fluids and Their Relationship in the Exploration for Metamorphosed Massive to the Formation of Metamorphosed and Sulfide Ores Metamorphogenic Ore Deposits Paul G. Spry I. Cartwright and N. H. S. Oliver .ABSTRACT ...... 149 ABsTRACT ...... 81 INTRODUCFION •..•...•..•••••: •..•..•..•.•••••••••••••.••••.•.•...••.•••...•. 149 INTRODUCTION ...... 81 FERROMAGNESIAN.SILICATES ...... : ...... 150 FLUIDS IN METAMORPHIC TERRANES ...... 82 ZINCIAN SPINEL (GAHNITE) AND ZINCIAN STAUROLITE ••. 156 VARIATIONS IN FLUID PRODUCTION IN TIME AND SPACE ..••85 DISCUSSION AND APPLICATION TO EXPLORATION ...... 157 FLUID MIGRATION AND CHANNELING ...... 85 AcKNOWLEDGMENTs ...... 159 VEINS •••••.•••••••••• ; ...... 88 REFERENCES ;·,.:;·;·••••••..••••••• •• •• : ••••••••...•••••••••••••••••••••••.•••••••• 159 METAL TRANSPORT AND ORE DEPOSITS.•••••••••••.•....••••••••••• 89 \ DISCUSSION ...... 89 Chapter 8-Meta-Exhalites as Exploration Guides to Ore SUMMARY ...... 92 Paul G. Spry, Jan M. Peter, andJohn F. Slack ACKNOWLEDGMENTS ...... 92 .ABSTRACT ...... 163 REFERENCES ...... 92 INTRODUCTION ...... 163 IRON FORMATIONS ...... 164 CHARACTERIZATION OF THE HOST ROCKS ...... 240 COTICULES ...... 175 CHARACTERIZATION OF ORE MINERALS ...... 252 TOURMALINITES ...... 180 SuMMARY oF HosT-RocK AND ORE MINERAL DATA ...... 254 APATITE-RicH R ocKS ...... ) ...... 186 INTERPRETATION OF THE DATA ...... 256 -GAHNITE HORIZONS ...... : . .'...... 187 CONCLUSIONS ...... 260 STAUROLITE-BEARING ROCKS ...... ;· ...... 187 ACKNOWLEDGMENTS ...... 263 EXPLORATION GUIDES ...... 187 REFERENCES ...... 263 SUMMARY ...... ;.··· .., ...... 193 ACKNOWLEDGMENTS •... ;...... 194 Chapter 12-Gold Deposits in Amphibolite and Gran­ REFERENCES ...... : ...... 195 ulite Facies Terranes of the Archean Yilgarn Craton, Western Australia: Evidence and Implications of Syn­ Chapter 9-Metamorphism of Komatiite-Hosted Nickel metamorphic Mineralization Sulfide Deposits J Ridley, D. I. Groves, andJ T. Knight Stephen J Barnes and Robin E. T. Hill ABSTRACT ...... 265 ABSTRACT ...... 203 INTRODUCTION ...... 266 INTRODUCTION ...... 203 GEOLOGIC SETTING: HIGHER METAMORPHIC GRADE 'IYPES OF KOMATIITE-HOSTED NICKEL DEPOSITS ...... 203 TERRANES OF THE YILGARN CRATON ...... 266 PHASE EQUILIBRIA ...... 204 LODE GOLD DEPOSITS IN AMPHIBOLITE AND LOW-TEMPERATURE METAMORPHISM OF GRANULITE FACIES TERRANES OF THE SULFIDE-BEARING ULTRAMAFIC ROCKS ...... 204 YILGARN CRATON ...... 268 HIGH-TEMPERATURE METAMORPHISM OF CONSTRAINTS OF THE TIMING AND CONDITIONS OF SULFIDE-BEARING ULTRAMAFIC ROCKS ...... 210 MINERALIZATION OF DEPOSITS IN CONCLUSIONS ...... 213 HIGH-TEMPERATURE TERRANES ...... 279 ACKNOWLEDGMENTS ...... 214 SUMMARY OF DISTINCTIVE TIMING CRITERIA ...... 284 REFERENCES ...... 214 IMPLICATIONS ...... 285 ACKNOWLEDGMENTS ...... 286 Chapter 10-Metamorphism of Ni-Cu Sulfides in REFERENCES ...... 287 Mafic-Ultramafic Intrusions: The Svecofennian Saaksjarvi Complex, Southern Finland Chapter 13--Subduction-Related Diamond Deposits? Franco Mancini and Heikki Papunen Constraints, Possibilities, and New Data from ABSTRACT ...... 217 Eastern Australia INTRODUCTION ...... 217 W. L. Griffin, Suzanne Y. 0 'Reilly, and Rondi M. Davies METAMORPHISM OF THE HOST ROCKS ...... 219 ABSTRACT ...... 291 METAMORPHISM AND DEFORMATION OF SULFIDES ...... 224 INTRODUCTION ...... 291 CONCLUSIONS ...... 229 POSSIBLE EXAMPLES OF PHANEROZOIC ACKNOWLEDGMENTS ...... 230 SUBDUCTION-RELATED DIAMONDS ...... 293 REFERENCES ...... 230 CONSTRAINTS ON SUBDUCTION MODELS ...... 295 EAsTERN AusTRALIAN DIAMONDS: OccuRRENCE Chapter 11-Tungsten Mineralization and Metamorphic AND PREVIous WoRK...... 297 Remobilization in the Felbertal Scheelite Deposit, EASTERN AUSTRALIAN DIAMONDS: NEW DATA ...... 300 Central Alps, Austria EASTERN AUSTRALIAN DIAMONDS: A Rudolf Holt and Roland Eichhorn SUBDUCTION ORIGIN? ...... ············••·••···· ...... 303 ABSTRACT ...... ; ...... 233 SUMMARY ...... 307 INTRODUCTION ...... : ...... 234 ACKNOWLEDGMENTS ...... 308 THEORIES OF GENESIS ...... ;·...... 234 REFERENCES ...... 308 GEOLOGIC SETTING ...... 239 METAMORPHISM AND TECTONIC ACTM'IY ...... 239