Potential consequences of a Mid-Pleistocene impact event for the Middle Stone Age occupants of Dakhleh Oasis, Western Desert, Egypt

While it is expected that prehistoric populations experienced the effects of impacts by extraterrestrial objects, there is little record of such events in occupied regions. We discuss the ramifications of an impact between 100 and 200ka into Dakhleh Oasis, at that time experiencing humid phase conditions and inhabited by Middle Stone Age people. Based on modeling of impact processes using estimated impact parameters, the impact blast would likely have felled or dismembered most trees over 280–2400km2 of the oasis, and inhabitants would have been injured over much of the region, although severely only near the blast location. The impact would not have vaporized much of the Dakhleh paleolake(s), although some water was probably lost through boiling and through waves initiated by the impact blast. Water quality would have decreased as lake turbidity increased, and soot from regional fires fell into the lake. A relatively small event would not have immediately ignited much of the oasis vegetation, but sedimentary evidence suggests that impact-generated fires did spread to significantly affect the landscape. The impact and resulting fires may have triggered mass wasting events as well as significant changes in erosion rates and have substantially affected human uses of the area.