ESR(Electron Spin Resonance) Chronology Of The Sankeshu And Jijiazhuang Paleolithic Sites In The Nihewan Basin,North China

The well-developed Late Cenozoic lacustrine strata,rich Paleolithic sites and mammalian fossils in the Naihewan Basin are ideal areas for studying the origin and evolution of ancient humans,and have received wide attention from geologists,archaeologists and paleontologists at home and abroad.More than 100 Palaeolithic sites have been discovered in this basin,however,due to the lack of suitable dating methods,many important sites,especially those in the Middle Pleistocene period,lack absolute dating data,making the study of Palaeolithic sites lack the chronological framework of this period.Electron spin resonance dating is a dating technique developed in the 1970 s that is capable of determining the age of geological samples throughout the Quaternary range and has been widely accepted in practice by the geological community.For the determination of the age of Middle Pleistocene sites,the ESR method has achieved several successful examples and has broad application prospects.The Sankeshu site is located in the eastern part of the Neihewan Basin.A large number of stone tools and mammal fossils were excavated in 2008,especially several "Donggutuo Core",which provide important information for the study of the development of small stone tool culture in northern China,and is a valuable Paleolithic site.Stratigraphic comparisons and magnetic stratigraphic evidence suggest that the Sankeshu site is a Middle Pleistocene site,however there are no independent chronological studies.The Jijiazhuang site is located within the Yuxian Basin,which is an important part of the Nihewan Basin(senso lato)with well-developed Nihewan layers.The discovery of this site enriches the Paleolithic archaeological data of the Yuxian Basin,and it expands the geographic scope of ancient human activities in the Nihewan Basin(senso lato),providing valuable clues for studying the evolutionary migration and adaptive behavior of early ancient humans to their environment.The mammalian faunal facies and magnetic stratigraphic evidence likewise suggest that the Jijiazhuang site is a Middle Pleistocene site.In this study,the sediment samples from the Sankeshu and Jijiazhuang sites were independently dated using the quartz Ti-Li center ESR dating method,and the ages of the Sankeshu and Jijiazhuang sites were 599±70 ka and 545±40 ka,respectively.the dating of these two sites provides a necessary basis for understanding the evolution of ancient humans and the development of lithic culture in the Neihewan Basin.