Late Quaternary environmental change in central southern Africa: new data, synthesis, issues and prospects

Abstract

Much of the interior of central southern Africa is a sand sea, within which aeolian and lacustrine landforms and sediments of local and regional extent are preserved. Closed cave sites are restricted to very few locations, while fluvial systems traverse the margins of the interior. Until the early 1990s, chronologies of late Quaternary environmental and climatic changes developed for this region were based on only a limited number of proxy data sets, derived largely from lacustrine deposits and precipitates. In particular, directly determined ages from aeolian deposits, the most extensive suite of features in the region, were absent. The application of luminescence-dating techniques to dune sediments, and the development of further detailed chronologies from cave precipitates, is now providing a more comprehensive record for the last 50 ka, with some chronologies extending back a further 100 ka. We present and review these data, assess their contribution to enhanced understanding of late Quaternary environmental changes in the region, and for the first time assess them against corrected radiocarbon ages from lacustrine sites. It is concluded that there is now an enhanced understanding of the spatial and temporal complexity of climate changes affecting the region in the last glacial cycle, including a complex record of punctuated aridity, but that many issues, including data-set integration and forcing mechanism controls, are imperfectly understood.