Abstract
The Postmasburg Mn/Fe-ores occur exclusively in dolomitic Precambrian sinkhole structures with siliceous breccias and shales as hostrocks. The main manganese minerals are braunite and bixbyite, apart from secondary alteration products of the psilomelane-manganomelane family. Various generations of ore minerals could be identified. The ore mineralization is subdivided into three different genetic types. They are classified either as pure karst deposits or as combined formations of karst origin and shallow marine sedimentation due to the transgression of the Banded Iron Formation (BIF) sea. Post-sedimentary metamorphism is identified as very low grade. The development of the different ore types is illustrated schematically.
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Altermann, W., Hälbich, I.W. (1990) Thrusting, folding and stratigraphy of the Ghaap Group along the southwestern margin of the Kaapvaal Craton. S. Afr. J. Geol. 4:553–566
Altermann, W., Hälbich, I.W. (1991) Structural history of the south-western corner of the Kaapvaal Craton and the adjacent Namaqua realm. Precambrian Res. 52:133–166
Barton, E.S., Altermann, W., Williams, I.S., Smith, C.B. (1994) U-Pb zircon age for a tuff in the Campbell Group, Griqualand West Sequence, South Africa: implications for Early Proterozoic rock accumulation rates. Geology 22:343–346
Beukes, N.J. (1978) Die Karbonaatgesteentes en Ysterformasies van die Transvaal Supergroep en Noord-Kaapland. Ph.D. thesis, Unpublished, Rand Afrikaans University, Johannesburg, 580 pp
Beukes, N.J. (1986) The Transvaal Sequence in Griqualand West. In: Anhaeusser, C.R., Maske, S. (eds.) Mineral deposits of Southern Africa. The Geological Society of South Africa, Johannesburg, pp. 818–828
Beukes, N.J. (1993) A review manganese deposits associated with the Early Proterozoic Transvaal Supergroup in Northern Cape Province, South Africa 16th Colloquium on African Geology, Ezulwini, Swaziland (abstract) 5 pp
Beukes, N.J., Smit, C.A. (1987) New evidence for thrust faulting in Griqualand West, South Africa: implications for stratigraphy and the age of red beds. S. Afr. J. Geol. 90 (4): 378–394
Beukes, N.J., Klein, C., Kaufman, A.J., Hayes, J.M. (1990) Carbonate petrography, kerogen distribution, and carbon and oxygen isotope variations in an Early Proterozoic transition from limestone to iron-formation deposition, Transvaal Supergroup, South Africa. Econ. Geol 85 (4): 665–690
Boardman, L.G. (1940) The geology of the manganese deposits on Aucampsrust, Postmasburg. Trans. Geol. Soc. S. Afr. 3:27–36
Bögli, A. (1978) Karsthydrographie und physische Speläologie. Springer, Berlin Heidelberg New York, 292 pp
Borchert, H. (1970) Lagerstättenkunde des Mangans. Glückauf, Essen, 160 pp
De Villiers, J. (1960) The manganese deposits of the Union of South Africa. Handbook 2 of the Geological Survey. Government Printer, Pretoria, 280 pp
De Villiers, J.E. (1944) The origin of the iron and manganese deposits in the Postmasburg and Thabazimbi areas. Trans. Geol. Soc. S. Afr. 47:123–135
De Villiers, J.E. (1983) The manganese deposits of Griqualand West, South Africa: some mineralogical aspects. Econ. Geol. 78:1108–1118
Frenzel, G. (1980) The manganese ore minerals. In: Varentsov, I.M., Grasselly, G.Y. (eds.) Geology and geochemistry of manganese I. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, pp. 25–157
Jahn, B.-M., Bertrand-Sarfati, J., Morin, N., Mace, J. (1990) Direct dating of stromatolitic carbonates from the Schmidtsdrif Formation (Transvaal Dolomite), South Africa, with implications on the age of the Ventersdrop Supergroup. Geology 18:1211–1214
Leisen, H. (1987) Geologisch-tektonische Kartierung der Griqualand West and Olifantshoek Sequenzen in der Nördlichen Kapprovinz, Südafrika, auf der Grundlage von Landsat-Mss-Daten und terrestrisch-photogrammetrischen Aufnahmen. Unpublished Ph.D.-thesis, Ludwig-Maximilian-University, Müchen, pp. 118
Leleu, M. (1966) Le karst et ses incidentes métallogéniques. Sci. Terre 11(4): 385–413
Maissonneuve, J. (1982) The composition of the Precambrian ocean waters. Sed. Geol. 31:1–11
Mason, B. (1944) The system of Fe2O3-Mn2O3: some comments on the names bixbyite, sitaparite and partridgeite. Am. Mineral. 29:66–69
Nel, L.T. (1929) The geology of the Postmasburg manganese deposits and the surrounding country. Geol. Survey, Johannesburg, 109 pp
Plehwe-Leisen, E. (1985) Geologische und erzpetrographische Untersuchungen der Manganerze des Postmasburgfeldes, Nördliche Kapprovinz, Südafrica. Unpublished Ph.D.-thesis, Ludwig-Maximilian-University, München, 129 pp
Ramdohr, P. (1975) Die Erzmineralien und ihre Verwachsungen, 4. Aufl., Akademie, Berlin, 876 pp
SACS (South African Committee for Stratigraphy) (1980) Stratigraphy of South Africa, Handbook 8, Part 1 of the Department of Mineral and Energy Affairs. Government Printer, Pretoria, 690 PP
Schulz, O. (1982) Karst or thermal mineralizations interpreted in the light of sedimentary ore fabrics. In: Amstutz, C.G. El Goresy, A. (eds.) Ore genesis-The state of the art. Springer, Berlin Heidelberg New York, pp. 108–117
Trendall, A.F., Compstone, W., Williams, I.S., Amstrong, R.A., Arndt, N.T., McNaughton, N.J., Nelson, D.R., Barley, M.E., Beukes, N.J., Laeter, J.R. de Retief, E.A., Thome, A.M. (1990) Precise Zirkon U-Pb chronological comparison of the volcano-sedimentary sequences of the Kaapvaal and Pilbara cratons between about 3.1 and 2.4 Ga. Proceedings 3rd International Archean Symposium, Perth, pp. 81–83
Van Schalkwyk, J.F., Beukes, N.J. (1986) The Sishen iron ore deposit, griqualand West. In: Anhaeusser, C.R., Máske, S. (eds.) Mineral deposits of southern Africa. The Geological Society of South Africa, Johannesburg, pp. 931–956
Visser, D.J.L. (1944) Stratigraphic features and tectonics of portions of Bechuanaland and Griqualand West. Trans. Geol. Soc. S. Afr. 47:197–254
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von Plehwe-Leisen, E., Klemm, D.D. Geology and ore genesis of the manganese ore deposits of the Postmasburg manganese-field, South Africa. Mineral. Deposita 30, 257–267 (1995). https://doi.org/10.1007/BF00196361
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DOI: https://doi.org/10.1007/BF00196361