Palaeofluvial geomorphology in southern Africa: a review

Abstract

This article presents an overview of palaeofluvial geomorphology research in southern Africa. For the purposes of this article this includes South Africa, Zimbabwe, Namibia, Lesotho, Swaziland and Botswana. Although interest in fluvial systems has a long history in southern Africa, the scientific study of rivers was initiated by the discovery of the first alluvial diamond along the banks of the Orange River in 1867. Since then, significant progress has been made in unravelling the fluvial history of southern Africa from the early Archaean Ventersdorp Contact Reef River to modern channel process studies. The development of an understanding of palaeofluvial systems has occurred along two main lines. The first was alluvial diamond exploration work undertaken by the large mining houses. The second line was of a more ‘academic’ interest and included determining the impact of superimposition, tectonics, base level and climate changes. The review suggests that southern Africa fluvial systems have shown large-scale changes in drainage pattern, discharge and sediment yield and that these can be related to a complex set of causative factors including the geological template, the Jurassic rifting of Gondwana, tectonic episodes and climate change.