Crustal development in the Kaapvaal craton, II. The Proterozoic

Abstract

Abstract The distribution of the sedimentary basins, the granites and mafic complexes is illustrated and their essential features described. The Limpopo mobile belt that separates the Kaapvaal and Rhodesian cratons is briefly described. The generation of the granites in the setting of the craton is discussed and evidence is presented to support the conclusion that the granite magmas were, in part, mantle-derived and, in part, derived by partial melting of the Archaean sialic crust. The distinctive feature of the granites is that their locus of emplacement provides the source material for the sedimentary basins, the depositional axes of which migrated across the craton complementary to the northward migration of the locus of granite emplacement. The parallelism of the chronology of crustal deformation and of magmatism in the Kaapvaal craton leads to an attempt to identify a concept that links responses in the crust to processes in the mantle. It is proposed as a working hypothesis that the proposals of Shaw et al. (1971) can be applied to the Kaapvaal craton. This involves a complex interaction of heat exchange as result of the dissipative energy of solid earth tides.