Uranium in South Africa and South West Africa (Namibia)

Abstract

A number of genetically different uranium deposits occur in South Africa and South West Africa in rocks of widely differing ages. Early Proterozoic clastic rocks contain sedimentary uraninite, whose deposition in auriferous quartz-pebble conglomerates and carbon seams can be related to fluvial fans and algal mats. Recently discovered deposits of uranium in the Phanerozoic Karoo Supergroup occur as widespread but small bodies in channel sandstones of fluvial association. Carnotite deposits are developed in Cainozoic calcretes in the western, more arid, regions of southern Africa in which the uranium has been precipitated epigenetically from circulating groundwater. Uranium mineralization in magmatic rocks is present to a small extent in phoscorite and carbonatite of the middle Proterozoic Phalaborwa Igneous Complex, and is associated with alkaline lavas and intrusive rocks in the Pilanesberg alkaline complex of middle-late Proterozoic age. Multicyclic processes of ore formation have produced extensive deposits of uraninite-bearing alaskitic pegmatitic granites, of Phanerozoic age, in the Pan-African Damara metamorphic belt.