ESR DATING FOR A NEW MIDDLE PLEISTOCENE HOMINID INCISOR AND MIDDLE PALEOLITHIC ARTEFACTS FROM OIS 9 AT PRADAYROL, LOT, FRANCE

In 1999, a hominid tooth was found associated with extinct Middle Pleistocene fauna at Pradayrol, France. ²³⁰Th/²³⁴U dating failed to give ages for stalagmitic deposits, because the calcite was too badly altered. ESR (electron spin resonance), however, can date mammalian tooth enamel ranging in age from 5 ka to 5 Ma, with 2-10% precision, by comparing the accumulated radiation dose in the teeth with the total radiation dose rate from the tooth and its environment. Near Caniac-du-Causse, Lot, France, the Pradayrol site occurs in a large abri with fill reaching 10-15 m. Only two stratigraphic units were partially excavated, but the site yielded more than 1000 artefacts. Most were sidescrapers made from quartzite and flint or flaking debris forming a Denticulate Mousterian assemblage. The small tool size suggests in situ production and raw material parsimony. In Layer 2A, an upper right permanent incisor from an adult hominid was found, which compares well in size and features with the Neanderthal teeth from La Chaise-de-Vouthon. Also found in Layer 2A were numerous extinct Middle Pleistocene fauna, including Dicerorhinus mercki, Equus mosbachensis, Canis etruscus, and Ursus deningeri, all suggesting an age > 150 ka. In order to determine an absolute age, four bovid teeth from Layer 2A were dated by ESR. Eighteen independent analyses from two bovid teeth from the layer containing the incisor were dated by standard and isochron ESR. Twenty associated sediment samples were tested by neutron activation analysis to determine the volumetrically averaged external dose rate. Isochron analyses indicate no significant U remobilization and linear U uptake (LU). Assuming LU in the teeth and the uraniferous sedimentary components, the four teeth averaged 330 ± 5 ka, which corresponds to early Oxygen Isotope Stage (OIS) 9.