CAINOZOIC ENVIRONMENTAL-CHANGE IN SOUTHERN AFRICA, WITH SPECIAL EMPHASIS ON THE LAST 200 000 YEARS

Since the end of the Cretaceous, Africa's latitudinal drift has been r elatively small and has not significantly modified the general pattern of stepwise cooling and aridification that has characterized the Cain ozoic era. Tectonic uplift has, in contrast, strongly influenced regio nal climates in east and southern Africa, especially during the late N eogene, and has accentuated the east-west moisture gradient which has prevailed, with minor interruptions, since the Oligocene. In common wi th most other midlatitude regions, southern African environments respo nded dramatically to the global episode of cooling and drying between 2.8 and 2.6 myr which ushered in the cyclical fluctuations of the Plei stocene. The establishment of ii winter rainfall regime in the southwe stern part of the subcontinent probably dates from around 2.6 myr. In the north east, new proxy data spanning the last 200 000 years indicat e that summer rainfall varied in relation to receipts of solar insolat ion at precessional frequencies. Superimposed upon these cyclical chan ges were a number of less regular variations which, on the basis of th e larger body of evidence available for the Holocene, elicited specifi c localized responses. These diachronistic changes argue for the invol vement of factors other than solar insolation alone in the more recent evolution of southern African climates.