Tectonic evolution of the Cuvette Centrale, Zaire

Abstract

The Cuvette Centrale (Central Basin) of Zaire is an infra-Cambrian to Recent basin with up to 9 km of sedimentary section. Basin subsidence can be largely explained by a postulated Late Proterozoic failed rift and subsequent thermal relaxation. Seismic reflection profiles and well data reveal a Palaeozoic development of the basin punctuated by two regional deformational episodes; one in the Early Palaeozoic (Late Cambrian) and a second in the Late Palaeozoic (Late Permian-Triassic). Both episodes result from NE-SW contraction, with the Late Palaeozoic episode being largely a reactivation of the Early Palaeozoic structures. The timing of the two deformations correlates with collisional events at continental margins some distance from the Congo Basin. In the Early Palaeozoic the deformation appears to be related to the late stages of the West Congolian fold and thrust belt and coincides regionally with the Pan-African event sensu stricto. The Late Palaeozoic deformation coincides with collisional tectonics along the southern margin of Gondwana and the generation of the Cape and Sierra Ventana Foldbelts. It is postulated that in both the Early and Late Palaeozoic, Africa and Gondwana experienced widespread intracontinental deformation generated by distant collisional processes much as Central Asia is experiencing today.