DIRECT AGE ASSESSMENT OF MIDDLE PALAEOLITHIC AND LATER SKELETAL MATERIAL USING OPTICAL DATING

The accurate dating of human fossils, particularly diagnostic materials such as skulls, is a vitally important component in understanding the emergence and subsequent development of anatomically modern humans. The crucial middle-Palaeolithic period is beyond the range of 14C dating and sites generally contain little or no material for U-series or other radiometric dating techniques. Our approach has been to use Optical Dating to obtain ages for sediments attached to human skeletal material. Dating intra-cranial sedimentary material offers a potentially important new means by which age control may be generated for Middle Palaeolithic and other contexts where other dating approaches are not possible. Here we present dates for two skulls: (i) The ‘Hofmeyr skull’ discovered in Eastern Cape Province of South Africa displays both anatomically modern alongside distinctly archaic features. The presence of both distinctive modern and archaic attributes in the Hofmeyr skull give it great significance and may provide a key to understanding the transition from archaic to the modern form of humans. Attempts to date the skull using radiocarbon approaches have not been successful, due in part to high levels of decalcification. (ii) The ‘Taramsa skeleton’ found within a Middle Palaeolithic chert extraction pit on the Nile Valley (Egypt). The site contains remarkable assemblages of Middle Palaeolithic industries and the skeleton found in burial position is one of the most important finds in African palaeoanthropology. We discuss the association of the sediment and the burial age of the skulls. We also discuss the dosimetry which is complex and non-uniform in such archaeological contexts, with particular attention paid to the development of a numerical model of radiation dose deposition during burial. This approach offers a novel means of establishing the post mortem age of new and previously collected Middle Palaeolithic skeletal remains.