Post-Gondwana pedogenic ferromanganese deposits, ancient soil profiles, African land surfaces and palaeoclimatic change on the Highveld of South Africa

Mineralogy, geochemistry and geological occurrence of supergene manganese ore mineralization in North West Province, South Africa

“…African erosional surfaces termed African 1 and African 2 surfaces of erosion which are estimated to have started developing during the late Cretaceous period in post-Gondwana times [Vafeas et al, 2018[Vafeas et al, , 2019. The widespread mineralization of secondary manganese oxide and oxyhydroxides is evident mostly in the form of barium and potassium-bearing manganese mineral phases across the latter platform which stretches from the town of Krugersdorp in the east to the town of Mafikeng in the west.…”

“…On the basis of the analyzed samples he came to a conclusion that the dolomites contained a relatively high content of manganese (up to 7.5 wt%) and can therefore represent protores from which the overlying supergene mineralization was derived [De Villiers, 1960]. Later a number of authors opened a research in the region where these deposits were studied in Ryedale Mine near the town of Ventersdorp and in the West-Wits Mine near Krugersdorp [Beukes et al, 1999;Gutzmer and Beukes, 1994;Pack et al, 2000;Van Niekerk et al, 1999a, 1999b. Their studies led to the discovery of a new deposit being hosted by the Permian Ecca strata of the Karoo Supergroup in Ryedale mine.…”

“…Therefore, De Villiers's ore genetic model had to be modified to include this newly discovered kind of ore deposit. Most of the research which was carried out in the North West region previously was mainly focused on studying the mineral constituents of manganese wad and therefore less attention was given to the manganese nodules mineralization in the overly-ing alluvium as they were often regarded as simply gravels coated with Mn oxyhydroxides [Beukes et al, 1999;Gutzmer and Beukes, 1994;Pack et al, 2000;Van Niekerk et al, 1999a, 1999b. Results on mineral composition of the wad have shown that the wad comprised mainly of cryptomelane and pyrolusite and other accessory minerals such as kaolinite, silica.…”

Detection of concealed Cu–Zn massive sulfide mineralization below eolian sand and a calcrete cover in the eastern part of the Namaqua Metamorphic Province, South Africa

“…Aridification and major climate deterioration were the most important climatic changes (Van Niekerk et al, 1999), which began during the late Pliocene (Partridge et al, 1987). These changes occurred together with major changes in the extent of the earth's ice caps, at the beginning of the middle Pleistocene (Partridge et al, 1987).…”

Precise SHRIMP U-Pb zircon age constraints on the lower Waterberg and Soutpansberg Groups, South Africa

“…Along this lineament folding of WUBS I and II took place prior to deposition of WUBS III (Figures 1 and 3A). The cause of this crustal shortening event, which not only reactivated the Thabazimbi-Murchison Lineament but also affected other strata on the Kaapvaal Craton as far south as the Witwatersrand area (Van Niekerk et al, 1999) is unknown. Either it is manifestation of a north-directed, compressional orogen that was situated to the south of the Kaapvaal Craton at that time, and that has since rifted away, or it represents far-field deformation related to the Limpopo Complex towards the end of deposition of WUBS II.…”