The Main Stages of the Late Quaternary Evolution of the Kalahari Region, Southern Africa

The palaeogeographical and palaeoclimatic development of the Kalahari region provides strong evidence that South African climatic changes in precipitation and temperature, as well as in surface winds are closely related to variations in intensity of the general circulation rather than in shifts of the climatic belts. According to the great diversity of palaeoclimatic evidence, the palaeo-climatic reconstruction is incomplete. Further finds of datable material will supplement this record and possibly add to the complexity of the evidence. The Middle Wisconsin interstadial period is characterized by pluvial conditions in the Kalahari (>30,000-ca. 19,000 yr BP). Last glacial maximum climatic conditions prevail between ca. 19,000 and 13.000 yr BP. A large increase in meridional and, over southern Africa, in W-E temperature gradients’ cause a change in the frequency of occurrence and in velocity of winds. The last glacial maximum was more arid in South West Africa than today, but more humid in the southern Kalahari than today. It is not quite clear whether the phase of greater glacial humidity in the Kalahari is restricted to only a short time span, probably between ca. 17,000 and 15.000 yr BP. The period between ca. 13,000 and 10,000 yr BP presents the transition from glacial climatic conditions to the post-glacial climatic optimum. During the Holocene temperature maximum around 9,500 yr BP geomorphic and palaeopedologic features indicate wetter conditions in the Kalahari. The results show that different palaeoclimatic indicators (geomorphic, sedimentological, palaeobotanical, palaeontological, archaeological, etc.) yield different time-stratigraphic periods for the Late Quaternary. That may be the reason, apart from the fact that many deposits have alternative explanations, that a great variety of palaeoclimatic and palaeogeographic reconstructions exist for southern Africa.