PLEISTOCENE STRATIGRAPHY, CHRONOLOGY, AND TAPHONOMY OF A TYPICAL MOUSTERIAN (MIDDLE PALEOLITHIC) SITE IN SAHARAN NORTH AFRICA

Middle Paleolithic sites that can be assigned to the Typical Mousterian are uncommon in the eastern Sahara Desert. One is located in southern Egypt at Bir Tarfawi. The artifacts were found lying on a surface composed of sandy mudstone plates, beneath pale brown sandy muds. The paleolandscape at the time the artifacts were deposited was probably the surface of a pan or seasonally dry lake. The muddy sands and sandy muds contain freshwater molluscs. The cemented plates likely were formed at a time when the surface of the basin became dry.

There are two taphonomic interpretations for the spatial distribution of the artifacts. There is some clustering of the artifacts which may be the result of redistribution of artifacts caused by a short intense episode of flooding. Another possibility is that the spatial distribution directly reflects Pleistocene hominid activity. The textures of the sediments (medium and fine sands and muds) imply a medium-to-low energy environment for transportation and deposition, connected with local rainfall and/or fluctuating groundwater levels.

The stratigraphy and chronology of the locality indicate the presence of pluvial conditions within the basin during the later part of the middle Pleistocene or the early late Pleistocene. The artifact-bearing playa-pan deposits unconformably overlie a freshwater limestone. Uranium-series dates on this limestone range from about 172 to 118 ka. Two sets of racemization dates on ostrich eggshell from the playa-pan deposits provide an approximate age of 130 to 125 ka. These dates may indicate that a large freshwater lake was present in the basin during oxygen isotope stage (OIS) 6. The Typical Mousterian assemblage may be associated with a less intense pluvial interval during the beginning of OIS 5.