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Mineralogy and mineral chemistry of oxide-facies manganese ores of the Postmasburg manganese field, South Africa

Published online by Cambridge University Press:  05 July 2018

J. Gutzmer  and
N. J. Beukes
J. Gutzmer
Affiliation:
Department of Geology, Rand Afrikaans University, P.O. Box 524, Auckland Park, 2006, South Africa
N. J. Beukes
Affiliation:
Department of Geology, Rand Afrikaans University, P.O. Box 524, Auckland Park, 2006, South Africa
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Abstract

The diagenetic to very low-grade metamorphic manganese ores of the Postmasburg manganese field provide a unique example of oxide-facies manganese ores in a Palaeoproterozoic palaeokarst setting. The ores are composed mainly of braunite group minerals, including braunite, partridgeite and bixbyite, with rare braunite II and Ca-poor, silica-depleted braunite. Iron-poor partridgeite is distinguished from Fe-rich bixbyite and the occurrence of Ca-poor, silica-depleted braunite is reported for the first time. Braunite and partridgeite formed during early diagenesis but remained stable under greenschist facies metamorphic conditions. In contrast, bixbyite is apparently a product of metasomatic remobilisation under peak metamorphic conditions. It is suggested that local variations of the metamorphic mineral association reflect variations of the host rock composition and that they are not related to changing P-T conditions of metamorphic alteration, a model promoted by previous authors. The phase chemistry of braunite, braunite II and bixbyite is explained by the existing polysomatic stacking model for the braunite group. However, the chemical composition of partridgeite and Ca-poor, silica-depleted braunite can only be explained by introducing a distinct module layer, with partridgeite composition, to the existing polysomatic stacking model.

Keywords

braunitebixbyitepartridgeiteCampbellrand SubgroupTransvaal Supergroupmanganese orePostmasburgSouth Africa
Type
Mineralogy
Information
Mineralogical Magazine , Volume 61 , Issue 405 , April 1997 , pp. 213 - 231
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1997

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References

Abs-Wurmbach, I. and Langer, K. (1975) Synthetic Mn3+-kyanite and viridine (Al2−x-Mnx 3+)SiO5, in the system Al2O3-MnO2-SiO2 . Contrib. Mineral. Petrol., 49, 21-38.CrossRefGoogle Scholar
Abs-Wurmbach, I., Peters, Tj., Langer, K. and Schreyer, W. (1983) Phase relations in the system Mn-Si-O and experimental and petrological study. Neues Jahrb. Mineral. Abh., 146, 258-79.Google Scholar
Afifi, A.M. and Essene, E.J. (1988) Minfile Version 3-88 (software package).Google Scholar
Anovitz, L.M., Perkins, D. and Essene, E.J. (1991) Metastability in near-surface rocks of minerals in the system Al2O3-SiO2-H2O. Clays Clay Miner., 39, 225–33.CrossRefGoogle Scholar
Bárdossy, G. (1982) Karst Bauxites - Bauxite Deposits on Carbonate Rocks. Elsevier, Amsterdam, 441 pp.Google Scholar
Baudracco-Gritti, C. (1985) Substitution du manganese bivalent par du calcium dans les minéraux du groupe: Braunite, neltnerite, braunite II. Bulletin de Minéralogie, 108, 437-45.CrossRefGoogle Scholar
Beukes, N.J. (1986) The Transvaal Sequence in Griqualand West. In Mineral Deposits of Southern Africa (Annhaeusser, C.R. and Maske, S., eds.). Geol. Soc. S. Afr., Johannesburg, 1, 819-28.Google Scholar
Beukes, N.J. and Smit, C.A. (1987) New evidence for thrust faulting in Griqualand West, South Africa: Implications for stratigraphy and the age of red beds. Trans. Geol. Soc. S. Afr., 90, 378-94.Google Scholar
Brannath, A. and Smykatz-Kloss, W. (1992) Mineralogische Untersuchungen an einigen hes-sischeu Mangan-Eisenerzvorkommen. Chemie der Erde, 52 3–31.Google Scholar
Coles-Phillips, F.C. (1931) Ephesite (soda-margarite) from the Postmasburg district, South Africa. Mineral. Mag., 22, 482-5.Google Scholar
Chudoba, K. (1929) Über ‘Mangandiaspor’ und Manganophyll von Postmasburg (Griqualand West, Südafrika). Neues Jahrb. Mineral., Beilagen Band 64 A, 11-8.Google Scholar
Dasgupta, H.C. and Manickavasagam, R. (1981) Chemical and X-ray investigation of braunite from the metamorphosed manganiferous sediments of India. Neues Jahrb. Mineral. Abh., 142, 2, 149-60.Google Scholar
Dasgupta, S., Bannerjee, U., Fukuoka, M., Bhattacharya, P.K. and Roy, S. (1990) Petrogenesis of metamorphosed manganese deposits and the nature of the precursor sediments. Ore Geol. Rev., 5, 359—84.CrossRefGoogle Scholar
De Villiers, J. (1960) Manganese Deposits of the Union of South Africa. Geol. Surv. S. Afr., Pretoria, 280 pp.Google Scholar
De Villiers, J.E. (1943a) A preliminary description of the new mineral partridgeite. Amer. Mineral., 28, 336-8.Google Scholar
De Villiers, J.E. (1943b) Gamagarite, a new vanadium mineral from the Postmasburg manganese deposits. Amer. Mineral., 28, 329-35.Google Scholar
De Villiers, J.E. (1945a) Some minerals occurring in South African manganese deposits. Trans. Geol. Soc. S. Aft., 48, 17–25.Google Scholar
De Villiers, J.E. (1945b) Lithiophorite from the Postmasburg manganese deposits. Amer. Mineral., 30, 629-34.Google Scholar
De Villiers, J.E. (1983) The manganese deposits of Griqualand West, South Africa: Some mineralogic aspects. Econ. Geol., 78, 1108-18.CrossRefGoogle Scholar
De Villiers, J.E. (1992) On the origin of the Griqualand West manganese and iron deposits. S. Afr. J. Sci., 88, 12-5.Google Scholar
De Villiers, J.P.R. and Buseck, P.R. (1989) Stacking variations and nonstoichiometry in the bixbyite-braunite polysomatic mineral group. Amer. Mineral., 74, 1325-36.Google Scholar
De Villiers, P.R. and Herbstein, F.H. (1967) Distinction between two members of the braunite group. Amer. Mineral., 52, 20-30.Google Scholar
Feenstra, A. (1996) An EMP and TEM-AEM study of margarite, muscovite and paragonite in polymeta-morphic metabauxites of Naxos (Cyclades, Greece) and the implications of fine-scale mica interlayering and multiple mica generations. J. Petrol., 37, 201-33.CrossRefGoogle Scholar
Frenzel, G. (1980) The manganese ore minerals. In Geology and Geochemistry of Manganese (Varentsov, I.M. and Grasselly, Gy., eds.). Schweizerbartsche Verlagsbuchhandlung, Stuttgart, 1, 25–157.Google Scholar
Grobbelaar, W.S. and Beukes, N.J. (1986) The Bishop and Glosam manganese mines and Beeshoek iron ore mine of the Postmasburg area. In Mineral Deposits of Southern Africa (Annhaeusser, C.R. and Maske, S., eds.). Geol. Soc. S. Afr., Johannesburg, 1, 957-61.Google Scholar
Gutzmer, J. (1996). Genesis and alteration of the Kalahari and Postmasburg manganese deposits, Griqualand West. South Africa. PhD thesis (unpubl.), RAU, Johannesburg, 513 pp.Google Scholar
Gutzmer, J. and Beukes, N.J. (1995). Fault-controlled metasomatic alteration of Early Proterozoic sedi-mentary manganese ores in the Kalahari manganese field, South Africa. Econ. Geol., 90, 823-44.CrossRefGoogle Scholar
Hall, A.L. (1926) The manganese deposits near Postmasburg, West of Kimberley. Trans. Geol. Soc. S. Afr., 29, 17-66.Google Scholar
Harlow, G.E., Dunn, P.J. and Rossman, G.R. (1984) Gamagarite: A reexamination and comparison with brackebuschite-like minerals. Amer. Mineral., 69, 803-6.Google Scholar
Hou, B. (1994) Primary braunite in Triassic sedimentary manganese deposits of Dounan, Yunnan, China. Ore Geol. Rev., 9, 219-39.Google Scholar
Kleyenstüber, A.S.E. (1985) A regional mineralogical study of the manganese-bearing Voëlwater Subgroup in the Northern Cape Province. PhD thesis (unpubl.), RAU, Johannesburg, 328 pp.Google Scholar
Mason, B. (1944) The system Mn2O3-FezO3: Some comments on the names bixbyite, sitaparite and partridgeite. Amer. Mineral., 29, 66—9.Google Scholar
McSwiggen, P.L., Morey, G.B. and Cleland, J.M. (1994) The origin of aegirine in iron formation of the Cuyuna Range East Central Minnesota. Canad. Mineral., 32, 589-98.Google Scholar
Nel, L.T. (1929) The geology of the Postmasburg manganese deposits and the surrounding country. Explanation of the geological map. Geol. Surv. S. Aft., Pretoria, 109 pp.Google Scholar
Nell, J., Pollak, H. and Lodya, J.A. (1994) Intersite cation partitioning in natural and synthetic alpha-(Fe,Mn)2O3 (bixbyite) solid solutions determined from 57Fe Mössbauer spectroscopy. Hyperfine Interactions, 91, 601-5.CrossRefGoogle Scholar
Ostwald, J. (1982) Some observations on the mineralogy and genesis of braunite. Mineral. Mag., 46, 506-7.CrossRefGoogle Scholar
Ostwald, J. (1992) Diagenetic and supergene braunites in the Proterozoic Manganese Group, Western Australia. Mineral Mag., 56, 611—6.CrossRefGoogle Scholar
Ostwald, J. and Bolton, B.R. (1990) Diagenetic braunite in sedimentary rocks of the Proterozoic Manganese Group, Western Australia. Ore Geol. Rev., 5, 315-23.CrossRefGoogle Scholar
Ostwald, J. and Nayak, V.K. (1993) Braunite mineralogy and paragenesis from the Kajlidongri mine, Madhya Pradesh, India. Mineral. Depos., 28, 153—-6.CrossRefGoogle Scholar
Plehwe-Leisen, E. von (1985) Geologische und erzpe-trographische Untersuchungen der Manganerze des Postmasburgfeldes, Nördliche Kapprovinz, Südafrika. Dissertation (unpubl.), Ludwig-Maximilians Universitäit München, Munich, 129 pp.Google Scholar
Ramdohr, P. (1969) The Ore Minerals and their lntergrowths. Pergamon Press, Oxford, 1174 pp.Google Scholar
Ramdohr, P. and Frenzel, G. (1956) Die Manganerze. In Symposium Sobre Yacimientos de Manganeso, Mexico City (J.G. Reyna, ed.), 19-73.Google Scholar
Rösler, H.J. (1984) Lehrbuch der Mineralogie (third edition). VEB Vedag, Leipzig, 833 pp.Google Scholar
Roy, S. (1981) Manganese Deposits. Academic Press, London, 458 pp.Google Scholar
Roy, S., Bandopadhyay, P.C., Perseil, E.A. and Fukuoka, M. (1990) Late diagenetic changes in manganese ores of the Upper Proterozoic Penganga Group, India. Ore Geol. Rev., 5, 341–57.CrossRefGoogle Scholar
Schneiderhöhn, H. (1931) Mineralbestand und Gefüge der Manganerze yon Postmasburg, Griqualand West, Stidafrika. Neues Jahrb. Mineral., Beilagen Band 64 A, 701-26.Google Scholar
Serdyuchenko, D.P. (1980) Precambrian biogenic-sedimentary manganese deposits. In Geology and Geochemistry of Manganese (Varentsov, I.M. and Grasselly, G., eds.). Schweizerbartsche Verlagsbuchhandlung, Stuttgart, 2, 61—88.Google Scholar
Van Schalkwyk, J.F. and Beukes, N.J. (1986) The Sishen iron ore deposit, Griqualand West. In Mineral Deposits of Southern Africa (Annhaeusser, C.R. and Maske, S., eds.). Geol. Soc. S. Afr., Johannesburg, 1, 931-56.Google Scholar
Van Wyk, J.P. (1980) Die geologie van die gebied Rooinekke-Matsap-Wolhaarkop in Noord-Kaapland met spesiale verwysing na die Koegas-Subgroep, Transvaal-Supergroep. MSc thesis (unpubl.), RAU, 159 pp.Google Scholar
Van Wyk, J.P. and Beukes, N.J. (1982) The geology of the Sishen iron ore deposit. In Proceedings. 12th CMMI Congress (H.W. Glen, ed.). Geol. Soc. S. Afr., Johannesburg, 203-11.Google Scholar