Comparison of Quaternary environmental change in eastern and southern Africa using cave speleothem, tufa and rock shelter sediment data

Abstract

Speleothem, tufa and sand dune age data for Namibia, Botswana and the Transvaal of South Africa have provided a detailed record of wet and dry periods in the southern African summer rainfall zone to 300 ka. Three sites record moister conditions between 202–186 ka. The period 50–14 ka was characterized by five wet periods at 50–43, 38–35, 31–29, 26–21, and 19–14 ka. There is also strong evidence for increased moisture during the mid and late Holocene from 6.9–2.6 and 1.8–0.5 ka. Ages from submerged speleothems in Namibia and for dune activity at Etosha Pan and in the Kalahari Desert indicate significant dry periods at 35–31, 29–28, and 11–8 ka. Speleothem, tufa and rock shelter sediment data for Somalia show wet conditions at 260–250, 176–172, 160, 116–113, 87–85, 13, 10, 7.5, 5, and 1.5 ka. The most obvious differences in the last 35 ka, between the two records, are that southern Africa experienced wet conditions in late glacial times, when East Africa was dry, and East Africa experienced wet conditions in the early Holocene, when southern Africa was dry.