Proterozoic crustal evolution in southwestern Africa.

Abstract

Recent work on the Precambrian Shield of southern Africa between the NE, 3500 m.y. old Kaapvaal and Zimbabwean Archaean nuclei and the SW, late Proterozoic-early Palaeozoic belts is reviewed. In the latter part of the subcontinent, no trace of Archaean crust has been confirmed, the oldest fragment being the 2000 m.y.-old volcanoplutonic Richtersveld subprovince. Palaeomagnetic reconstructions suggest the existence in the late Precambrian of the Adamastor Ocean, separating cratonic blocks in southern Africa and extending into South America and Antarctica.-P.Br.