On the ages of humid Late Quaternary phases in southern African arid areas (Namibia, Botswana)

Oxygen isotope stages 6 and/or 7 were the last significantly more humid phases relative to today in the Namib and Kalahari Deserts. That it has been more humid at that time is shown by 230Th/234U dates of speleothem from the Namib and the Kalahari. 230Th/234U dates obtained from calcretes and lacustrine chalk from the southwestern and central Kalahari, as well as TL dates obtained from dune sands from the Etosha area support the cave evidence. At the same time there is evidence for late Quaternary variations in precipitation. Hereby the eastern regions (Botswana) experienced higher variations than the western regions (Namib Desert). These variations could not yet be closely dated.