U-series Dating of Fossil Teeth and Carbonates from Snake Cave, Thailand

Abstract

Snake Cave (Thailand) is an important site for the study of the evolution in Southeast Asia, leading to a discovery of rich and various faunas, including a human tooth. Fossils of large and small mammals converge to indicate, on the basis of faunal assemblage, a late Middle Pleistocene age for the fossiliferous layers; on the other hand, previous U-series dating of carbonates furnished a lower limit for the fossils of about 130ky.In order to achieve a better comprehension of the chronology of the cave, the Uranium-series method for absolute age determination has been applied to some carbonates older than those studied previously and to fossils themselves.We used the isochron technique approach to yield valuable ages because spleleothem samples consist in a mixture of calcite and detrital contamination. The results obtained suggest that the main fossiliferous level is older than about 160ky. The application of the U-series method to tooth samples from this tropical cave leads to erroneous ages, probably because of post depositional groundwater movements.