UNRAVELLING PALEOLITHIC HOMININ ACTIVITY AT DAKHLEH OASIS, EGYPT: ESR DATING TEETH AND MOLLUSCS IN THE WESTERN DESERT

In Egypt’s hyperarid Western Desert, artesian spring deposits, buried soils, and lacustrine sediment, such as the calcareous silty sediment (CSS), all demonstrate that Dakhleh Oasis had surface water during at least four Quaternary pluvial periods. Paleolithic artefacts, fossil ungulate teeth, and snails all occur within the Pleistocene deposits and dot the modern deflated surface. During the late Middle Pleistocene, a paleolake with an area of > 60 km² existed, probably in a deflated basin belwo the Libyan Escarpment that likely formed during the Dakhleh impact event. The lake beds may have been > 10 m thick in places. South of Deir el Hagar at Bir Taleta, tooth fragments and Paleolithic tools, likely attributable to the Aterian and Middle Stone Age, and Neolithic artefacts sit in blowouts. The mid Holocene deposits form some of the surface, but Late Pleistocene and Holocene erosion has exposed the underlying red Palaeolake Kellis mud and silt, and in places, the Mut Formation shale, and the Taref Formation sandstone, thus deflating the heavier clasts from these layers to create the surficial lag. Artefacts ranging from Middle Stone Age (MSA) to Roman and modern debris occur in the lags and on the desert surface. Blowouts have also exposed Middle Pleistocene skeletal remains, including Gazella, Phacochoerus, Loxodonta africana, Hippopotamus, Pelorovis antiquus, Syncerus, Felis lybica, and Late Pleistocene bovids, equids, and other ungulates.

From Bir Taleta, > 50 herbivore tooth fragments and several mollusc shells have been independently dated with ESR using modelled time-averaged cosmic and sedimentary dose rates. Their age distribution shows that herbivores lived in the area briefly in early Marine (Oxygen) Isotope Stage (MIS) 3, molluscs for extended periods in MIS 1 and late 2, and herbivores in 5c-e, 6c, 7a, and 7c. During at least six periods during the later Quaternary, therefore, higher rainfall and/or groundwater tables made the Western Desert more habitable than today for herbivores, and thus, likely also for hominins in the absence of pumping technology.