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Gold-bismuth-telluride-sulphide assemblages at the Viceroy Mine, Harare-Bindura-Shamva greenstone belt, Zimbabwe

Published online by Cambridge University Press:  05 July 2018

T. Oberthür*
Affiliation:
Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, D-30655 Hannover, Germany
T. W. Weiser
Affiliation:
Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, D-30655 Hannover, Germany
*

Abstract

Gold mineralization at the Viceroy Mine is hosted in extensional veins in steep shear zones that transect metabasalts of the Archaean Arcturus Formation. The gold mineralization is generally made up of banded or massive quartz carrying abundant coarse arsenopyrite. However, most striking is a distinct suite of Au-Bi-Te-S minerals, namely joseite-A (Bi4TeS2), joseite-B (Bi4Te2S), hedleyite (Bi7Te3), ikunolite (Bi4S3), ‘protojoseite’ (Bi3TeS), an unnamed mineral (Bi6Te2S), bismuthinite (Bi2S3), native Bi, native gold, maldonite (Au2Bi), and jonassonite (AuBi5S4). The majority of the Bi-Te-S phases is characterized by Bi/(Se+Te) ratios of >1. Accordingly, this assemblage formed at reduced conditions at relatively low fS2 and fTe2. Fluid-inclusion thermometry indicates depositional temperatures of the main stage of mineralization of up to 342°C, in the normal range of mesothermal, orogenic gold deposits worldwide. However, melting temperatures of Au-Bi-Te phases down to at least 235°C (assemblage (Au2Bi + Bi + Bi7Te3)) imply that the Au-Bi-Te phases have been present as liquids or melt droplets. Furthermore, the close association of native gold, native bismuth and other Bi-Te-S phases suggests that gold was scavenged from the hydrothermal fluids by Bi-Te-S liquids or melts. It is concluded that a liquid/melt-collecting mechanism was probably active at Viceroy Mine, where the distinct Au-Bi-Te-S assemblage either formed late as part of the main, arsenopyrite-dominated mineralization, or it represents a different mineralization event, related to rejuvenation of the shear system. In either case, some of the gold may have been extracted from pre-existing, gold-bearing arsenopyrite by Bi-Te-S melts, thus leading to an upgrade of the gold ores at Viceroy. The Au-Bi-Te-S assemblage represents an epithermal-style mineralization overprinted on an otherwise mesothermal (orogenic) gold mineralization.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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References

Afifi, A.M., Kelly, W.C. and Essene, E.J. (1988a) Phase relations among tellurides, sulfides, and oxides: I. Thermodynamical data and calculated equilibria. Economic Geology, 83, 377394.CrossRefGoogle Scholar
Afifi, A.M., Kelly, W.C. and Essene, E.J. (1988b) Phase relations among tellurides, sulfides, and oxides: II. Application to telluride-bearing ore deposits. Economic Geology, 83, 395404.CrossRefGoogle Scholar
Baldock, J.W., Styles, M.T., Kalbskopf, S. and Muchemwa, E. (1991) The Geology of the Harare Greenstone Belt and Surrounding Granitic Terrain. Zimbabwe Geological Survey Bulletin, 94, 213 pp.Google Scholar
Bartholomew, D.S. (1990) Gold deposits of Zimbabwe. Zimbabwe Geological Survey, Mineral Resources Series, 23, 75 pp.Google Scholar
Bayliss, P. (1991) Crystal chemistry and crystallography of some minerals in the tetradymite group. American Mineralogist, 76, 257265.Google Scholar
Blenkinsop, T.G., Oberthiir, T. and Mapeto, O. (2000) Gold mineralization in the Mazowe area, Harare- Bindura-Shamva greenstone belt, Zimbabwe: I. Tectonic controls on mineralization. Mineralium Deposita, 35, 126137.CrossRefGoogle Scholar
Bowell, R.J., Foster, R.P. and Stanley, C. (1990) Telluride mineralization at the Ashanti gold mine, Ghana. Mineralogical Magazine, 54, 617627.CrossRefGoogle Scholar
Boyle, RW. (1979) The geochemistry of gold and its deposits. Geological Survey of Canada, Bulletin, 280, 584 pp.Google Scholar
Buchholz, P., Oberthiir, T., Liiders, V. and Wilkinson, J. (2007) Multistage Au-As-Sb mineralization and crustal-scale fluid evolution in the Kwekwe district, Midlands greenstone belt, Zimbabwe: A combined geochemical, mineralogical, stable isotope, and fluid inclusion study. Economic Geology, 102, 347378.CrossRefGoogle Scholar
Cepedal, A., Fuertes-Fuente, M., Martin-Izard, A., Gonzalez-Nistal, S. and Rodriguez-Pevida, L. (2006) Tellurides, selenides and Bi-mineral assemblages from the Rio Narcea Gold Belt, Asturias, Spain: genetic implications in Cu-Au and Au skarns. Mineralogy and Petrology, 87, 277304.CrossRefGoogle Scholar
Ciobanu, C. and Cook, N. (2002) Tellurides, selenides (and Bi-sulphosalts) in gold deposits. In Extended Abstracts, 11th Quadrennial IAGOD Symposium, Windhoek, Namibia, July 2002.Google Scholar
Ciobanu, C.L., Cook, NJ. and Spry, P.G. (2006a) Preface — Special Issue: Telluride and selenide minerals in gold deposits — how and why? Mineralogy and Petrology, 87, 163169.CrossRefGoogle Scholar
Ciobanu, C.L., Cook, N.J., Damian, F. and Damian, G. (2006a) Gold scavenged by bismuth melts: An example from Alpine shear-remobilizations in the Highis Massif, Romania. Mineralogy and Petrology, 87, 351384.CrossRefGoogle Scholar
Ciobanu, C.L., Birch, W., Pring, A. and Cook, NJ. (2007) Au-Bi-Te-S assemblages from Maldon gold deposit, Victoria, Australia. Geological Society of America Annual Meeting, Denver, 2007. GSA Abstracts with Programs, 39, No. 6, 626.Google Scholar
Cook, NJ. and Ciobanu, C.L. (2004) Bismuth tellurides and sulphosalts from the Larga hydrothermal system, Metaliferi Mts., Romania: Paragenesis and genetic significance. Mineralogical Magazine, 68, 301321.CrossRefGoogle Scholar
Cook, NJ. and Ciobanu, C.L. (2005) Tellurides in Au deposits: implications for modelling. Pp. 13871390 in: Mineral Deposit Research: Meeting the Global Challenge (Mao, J.W. and Bierlein, F.P., editors). Springer, Berlin Heidelberg, New York.CrossRefGoogle Scholar
Cook, NJ., Ciobanu, C.L., Wagner, T. and Stanley, CJ. (2007) Minerals of the system Bi-Te-Se-S related to the tetradymite archetype: Review of classification and compositional variation. The Canadian Mineralogist, 45, 665708.CrossRefGoogle Scholar
Dobbe, R. (1993) Bismuth tellurides (joseite B, bismuthian tsumoite) in a Pb-Zn deposit from Tunaberg, Sweden. European Journal of Mineralogy, 5, 165170.CrossRefGoogle Scholar
Dobosi, G. and Nagy, B. (1989) The occurrence of an Au-Bi sulfide in the Nagybörzsöny hydrothermal ore deposit, Northern Hungary. Neues Jahrbuch fur Mineralogie, Monatshefte, 1989, Heft 1, 814.Google Scholar
Douglas, N., Mavgrovenes, J., Hack, A. and England, R. (2000) The liquid bismuth collector model: An alternative gold deposition mechanism. In: Geological Society of Australia, 15th Australian Geological Convention, Sydney, Abstracts, 135.Google Scholar
Fleischer, R. and Routhier, P. (1973) The consanguineous origin of a tourmaline-bearing gold deposit: Passagem de Mariana (Brazil). Economic Geology, 68, 1122.CrossRefGoogle Scholar
Foster, R.P. and Piper, D.P. (1993) Archaean lode gold deposits in Africa - crustal setting, metallogenesis and cratonization. Ore Geology Reviews, 8, 303347.CrossRefGoogle Scholar
Foster, R.P. and Wilson, J.F. (1984) Geological setting of Archaean gold deposits in Zimbabwe. Pp. 521551 in: Gold 82: The Geology, Geochemistry and Genesis of Gold Deposits (Foster, R.P., editor.), Balkema, A.A., Rotterdam, The Netherlands.Google Scholar
Foster, R.P., Mann, A.G., Stowe, C.W. and Wilson, J.F. (1986) Archaean gold mineralization in Zimbabwe. Pp. 43112 in: Mineral Deposits of Southern Africa (Anhaeusser, C.R. and Maske, S., editors). Geological Society of South Africa, Johannesburg, South Africa.Google Scholar
Frost, B.R., Mavrogenes, J.A. and Tomkins, A.G. (2002) Partial melting of sulfide ore during medium- and high-grade metamorphism. The Canadian Mineralogist, 40, 1 — 18.CrossRefGoogle Scholar
Godovikov, A.A., Kochetkova, K.V. and Lavrent'ev, Yu. G. (1970) Study of the bismuth sulfotellurides of the Sokhondo deposit. Geologija i Geqfizika, 11, 123127 (in Russian).Google Scholar
Goldfarb, R.J., Groves, D.I. and Gardoll, S. (2001) Orogenic gold and geologic time: a global synthesis. Ore Geology Reviews, 18, 175.CrossRefGoogle Scholar
Groves, D.I., Goldfarb, R.J., Gebre-Mariam, M., Hagemann, S.G. and Robert, F. (1998) Orogenic gold deposits: a proposed classification in the context of their crustal distribution and relationship to other gold deposit types. Ore Geology Reviews, 13, 727.CrossRefGoogle Scholar
Groves, D.I., Goldfarb, R.J., Robert, F. and Hart, C.J. (2003) Gold deposits in metamorphic belts: overview of current understanding, outstanding problems, future research, exploration significance. Economic Geology, 98, 129.Google Scholar
Hamasaki, F., Murao, S., Hoshino, K., Watanabe, M. and Soeda, A. (1986) Unnamed Au-Bi sulfide from the Tsugahira mine, southern Kyushu, SW Japan. Neues Jahrbuch für Mineralogie Monatshefte, 1986, Heft 9, 416422.Google Scholar
Kalbskopf, S. (2002) The Economic Geology of the Bindura Greenstone Belt and Surrounding Terrain. Zimbabwe Geological Survey Bulletin, 97, Part 2, 203 pp.Google Scholar
Kontoniemi, O., Johanson, B., Kojonen, K. and Pakkanen, L. (1991) Ore mineralogy of the Osikonmäki gold deposit, Rantasalmi, southeastern Finland. Geological Survey of Finland, Special Paper, 12, 8189.Google Scholar
Ladeira, E. A. (1991) Genesis of gold in Quadrilatero Ferrifero: A remarkable case of permanency, recycling and inheritance. Pp. 11—30 in: Brazil Gold ‘91 (Ladeira, E.A., editor), Balkema, A.A., Rotterdam, The Netherlands.Google Scholar
Lehrberger, G., Preinfalk, C. Morteani, G. and Lahusen, L. (1990) Stratiforme Au-As-Bi-Vererzung in Cordierit-Sillimanit-Gneisen des Moldanubikums bei Oberviechtach-Unterlangau, Oberpfalzer Wald (NE-Bayern). Geologica Bavarica, 95, 133176.Google Scholar
Maufe, H.B. (1920) The Geology of the Enterprise Mineral Belt. Geological Survey of South Rhodesia, Bulletin, 7, 55 pp.Google Scholar
Nekrasov, I.J., Iakovlev, J.V., Soloviev, L.I. and Leskova, N.V. (1988) On the first find of a new gold-bismuth sulfide. Doklady Akademii Nauk SSSR, 299, 2, 438441 (in Russian).Google Scholar
Nickel, E.H. and Nichols, M.C. (2002) Mineral Database. Materials Data Inc., Livermore, CA, USA.Google Scholar
Oberthür, T., Vetter, U., Schmidt Mumm, A., Weiser, T., Amanor, J.A., Gyapong, W.A. Kumi, R. and Blenkinsop, T.G. (1994a) The Ashanti gold mine, Obuasi, Ghana: Mineralogical, geochemical, stable isotope and fluid inclusion studies on the metallogen-esis of the deposit. Geologisches Jahrbuch, D100. 31129.Google Scholar
Oberthür, T., Weiser, Th., Müller, P., and Schmidt Mumm, A. (1994a) Die Viceroy Goldmine, Arcturus, Simbabwe: Erste Daten einer ungewöhn-lichen Golderzparagenese. European Journal of Mineralogy, 6, Beiheft 1, 203.Google Scholar
Oberthür, T., Blenkinsop, T.G., Hein, U.F., Höppner, M., Hohndorf, A. and Weiser, T.W. (2000) Gold mineralization in the Mazowe area, Harare-Bindura-Shamva greenstone belt, Zimbabwe: II. Genetic relationships deduced from mineralogical, fluid inclusion and stable isotope studies, and the Sm-Nd isotopic composition of scheelites. Mineralium Deposita, 35, 138156.Google Scholar
Paar, W.H., Putz, H., Roberts, A.C., Stanley, CJ. and Culetto, F. (2006) Jonassonite, Au(Bi,Pb)5S4, a new mineral species from Nagyborzsony, Hungary. The Canadian Mineralogist, 44, 11271136.CrossRefGoogle Scholar
Pals, D.W. and Spry, P.G. (2003) Telluride mineralogy of the low-sulfidation epithermal Emperor gold deposit, Vatukoula, Fiji. Mineralogy and Petrology, 79, 285307.CrossRefGoogle Scholar
Pals, D.W., Spry, P.G. and Chryssoulis, S. (2003) Invisible gold and tellurium in arsenic-rich pyrite from the Emperor gold deposit, Fiji: Implications for gold distribution and deposition. Economic Geology, 98, 479493.Google Scholar
Pavlova, Z.N., Levin, V.L. and Tasov, B.M. (1991) New forms of occurrence of gold and bismuth in a copper-gold ore deposit of Kazakhstan. Izvestiya Akademiya Nauk Kazakhskoy SSR, 1991, 3, 6368 (in Russian).Google Scholar
Schmidt Mumm, A., Blenkinsop, T., Oberthür, T. and Weiser, Th. (1994) The Viceroy gold mine, Harare-Bindura greenstone belt, Zimbabwe: Structural setting, stable isotopes and fluid inclusion studies. European Journal of Mineralogy, 6, Beiheft 1, 252.Google Scholar
Schmidt Mumm, A., Blenkinsop, T. and Oberthür, T. (1995) The mineralization at the Viceroy gold mine, Harare-Bindura greenstone belt, Zimbabwe. Boletin Sociedad Española Mineralogia, 18-1, 224225.Google Scholar
Shackleton, J.M., Spry, P.G. and Bateman, R. (2003) Telluride mineralogy of the Golden Mile deposit, Kalgoorlie, Western Australia. The Canadian Mineralogist, 41, 15031524.CrossRefGoogle Scholar
Stocklmayer, V.R., Stidolph, P.A. and Clay, A. (1979) The Geology of the Salisbury-Enterprise Gold Belt. Rhodesian Geological Survey, Annals, IV (1978), 112.Google Scholar
Tomkins, A.G., Pattison, D.R. and Zaleski, E. (2004) The Hemlo gold deposit, Ontario: an example of melting and mobilization of a precious metal-sulfosalt assemblage during amphibolite facies metamorphism and deformation. Economic Geology, 99, 10631084.CrossRefGoogle Scholar
Tomschi, H.P. (1987) Goldvorkommen im Archaischen Harare-Bindura-Greenstone Belt, Zimbabwe: Zusammenhänge zwischen Lagerstattenbildung und Greenstone Belt Entwicklung. PhD thesis, University of Cologne, Germany, 257 pp.Google Scholar
Türmänen, T.O. and Koski, R.A. (2005) Gold enrichment and the Bi-Au association in pyrrhotite-rich massive sulfide deposits, Escanaba trough, southern Gorda ridge. Economic Geology, 100, 1135—1150.Google Scholar
Twemlow, S.G. (1984) Archaean gold-telluride mineralization of the Commoner Mine, Zimbabwe. Pp. 469492 in: Gold ‘82 (Foster, R.P., editor), Balkema, A.A., Rotterdam, The Netherlands.Google Scholar
Vial, D.S., Fusikawa, K., Castro, E.P. and Vieira, M.M. (1988) The sulfide tourmaline-quartz-vein gold deposit of Passagem de Mariana, Minas Gerais, Brazil. Geological Society of Australia, Abstract series (Gold ‘88), 22, 3035.Google Scholar
Vial, D.S., Duarte, B.P., Fusikawa, K. and Vieira, M.B. (2007) An epigenetic origin for the Passagem de Mariana gold deposit, Quadrilatero Ferrifero, Minas Gerais, Brazil. Ore Geology Reviews, 32, 596613.CrossRefGoogle Scholar
Warren, H.V. and Peacock, M.A. (1945) Hedleyite, a new bismuth telluride from British Columbia, with notes on wehrlite and some bismuth-tellurium alloys. University Toronto Studies, Geology Series, 49, 5569.Google Scholar
Zav'lyalov, E.M. and Begizov, V.D. (1983) New data on the constitution and nomenclature of the sulfotellurides of bismuth of the joseite group. Zapiski Vsesoyuznogo Mineralogicheskogo Obshchestva, 111, 589601 (in Russian).Google Scholar