Mineral resources of Southern Africa in time-stratigraphic perspective

The tectono-stratigraphic setting of mineral deposits in southern Africa is reviewed with reference to 5 outline maps portraying stages in the evolution of the subcontinent.The Early and Middle Archaean Eras are characterized by deposits of Cr, Au and Fe; the Late Archaean by Au, U and Ni. In the Early Proterozoic the intrusion of vast mafic complexes supplied Cr, Ni, Pt, Cu and V-Fe ore, while sedimentary basins received Fe, Mn, Cu, Pb and Zn in marginal seas. The Middle Proterozoic was a singularly poor metallogenic Era, producing only pegmatite minerals and a variety of Cu deposits. The Late Proterozoic is typified by widespread occurrence of Cu, Pb, Zn and local U in geosynclinal belts; pegmatite minerals formed on a large scale in rejuvenated basement. Carbon is the most important element of Phanerozoic deposits, accounting for the fossil fuels besides appearing as diamond in kimberlite. It also contributed to the precipitation of sandstone-type U. Post-Gondwana morphology and climate effected further surface concentration and dispersal of minerals.