Lacustrine Paleoenvironments of the Area of Bir Tarfawi-Bir Sahara East Reconstructed from Fossil Ostracods and the Chemistry of their Shells

Abstract

Several seasons of detailed geoarchaeological work by the Combined Prehistoric Expedition have shown that the climate in this now hyper-arid sector of the Eastern Sahara was considerably wetter on a number of occasions during the past two hundred thousand years (Wendorf and Schild 1980; Kowalski et al. 1989; Szabo et al. 1989). During these more humid intervals, the water-tables were often very close to the surface and shallow lakes occupied deflational hollows in the general vicinity of Bir Sahara East and Bir Tarfawi in the southwestern desert of Egypt. In both localities, at least five discrete lake events have been identified, although it is not certain that the Sahara East lakes were synchronous with those at Tarfawi. The two oldest lakes at Tarfawi, the Sand Pan and the Tarfawi White Lake, may date respectively to 175 and 160 ka; three younger Tarfawi lakes (Grey Phases 1–3 of the East Lake) all have Uranium-series ages closely bracketed within a period of 10 kyr about 135 ka, although preliminary thermoluminescence dates are consistently younger (Chs. 13 and 14, this volume). The youngest lake at Tarfawi, the Green Phase, may date to about 70 ka.