High-precision U-series dating of Panxian Dadong hominin site, Guizhou Province, southwestern China

Abstract

Panxian Dadong, an important hominin cave site in Guizhou Province, southwestern China, has yielded significant discoveries, including four hominin teeth, thousands of stone artifacts and abundant mammalian fossils. Previous dating efforts, such as preliminary U-series dating of speleothem samples with alpha spectrometry, subsequent coupled ESR/U-Th dating of fossil teeth, and OSL dating of sediments yielded broadly consistent age results. These studies have widely placed the site within late Middle Pleistocene. In this study, we present updated systematic U-Th dating results obtained using high-precision multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The new data reveal that speleothem samples from bottom to top in Areas A and C yielded age ranges of 389 to 96 ka and 418 to 33 ka, respectively. In particular, Layer I in Area C was dated to 100-33 ka, indicating that human occupation of the site extended into the Late Pleistocene. A Bayesian analysis refined the age constraints for the hominin fossil-containing Layers VII-II in Area C to approximately ∼320-113 ka, suggesting an earlier dispersal to the region, potentially representing Denisovans or the recently proposed Homo juluensis. Additionally, the artifact-bearing deposits between the fourth and third flowstone layers in Area A, were dated to 389-285 ka, establishing Panxian Dadong as one of the earliest hominin settlement sites in southwestern China during the Middle Pleistocene.