The problems in ESR dating of tooth enamel of Early Pleistocene and the age of Longgupo hominid, Wushan, China

Quite often ESR dating of tooth enamel provides underestimated ages. The fa ctors, which may account for the age suppression are studied. For dating of the samples of Early Pleistocene, thermal fading of the g = 2.0018 signal during the burial time may also lead toage underestimation. Isothermal anne aling of the g = 2.0018 line was studied in this work and a mixed first- an d second-order kinetics was observed. Its implication to the practical dati ng purpose is discussed. It is suggested that if no uranium leakage is dete cted, ESR EU ages of Early Pleistocene enamel samples should be considered only as the lower limits of the true ages. Combined ESR and magnetic dating of the Longgupo profile, Wushan, China, assigns the Olduvai subchron to th e fossil hominid-bearing layers of 7-8 of this profile. (C) 2000 Elsevier S cience Ltd. Ail rights reserved.