A giant African lake basin is providing information about possible migration routes and hunting practices of early humans in the Mesolithic and Neolithic, between 150,000 and 10,000 years ago.
     Oxford University researchers have unearthed new evidence from the lake basin in Botswana that suggests that the region was once much drier and wetter than it is today. They have documented thousands of stone tools on the lake bed, which sheds new light on how humans in Africa adapted to several substantial climate change events during the period that coincided with the last Ice Age in Europe.
     Researchers from the School of Geography and the Environment at the University of Oxford are surveying the now-dry basin of Lake Makgadikgadi in the Kalahari Desert. Their research was prompted by the discovery of the first of what are believed to be the world's largest stone tools on the bed of the lake. Although the first find was made in the 1990s, the discovery of four giant axes has not been scientifically reported until now. Four giant stone hand axes, measuring over 30 cm long and of uncertain age, were recovered from the lake basin. Equally remarkable is that the dry lake floor where they were found is also littered with tens of thousands of other smaller stone-age tools and flakes, the researchers report.
     Professor David Thomas, Head of the School of Geography and the Environment at the University of Oxford, said: "Many of the tools were found on the dry lake floor, not around its edge, which challenges the view that big lakes were only attractive to humans when they were full of water. It's likely that early human populations would have seen this area as a prolific hunting ground when food resources in the region were more concentrated than at times when the regional climate was wetter and food was more plentiful and the lake was full of water."
     Co-researcher Dr Sallie Burrough has dated the sediment and shorelines of the lake basin, which has shown that the mega lake was filled with water on multiple occasions in the last 250,000 years. Professor Thomas said: "The interior of southern Africa has usually been seen as being devoid of significant archaeology. Surprisingly, we have found and logged incredibly extensive Middle Stone Age artefacts spread over a vast area of the lake basin."
     The new research is the first time that this giant Botswanan lake basin in southern Africa has been the focus of scientific research, and these findings could provide new evidence to support the theory about a hominid migration through and expansion from Africa. Professor Thomas and Dr Burrough are planning further research into how the lake was formed and how it came and went. New research, beginning in 2010 and funded by the Leverhulme Trust, will investigate possible links between the lake basin and the Zambezi River.

Source: Physorg (10 September 2009)