The Age Determination Of The Yihe And Xihoudu Sites Based On The Evolution Of The Regional River And Lake Environment

The history of evolution of ancient humans has always been one of the major concerns of archeology and paleoanthropology.According to the existing research results,the evolutionary stages of ancient humans can be divided into:Homo habilis,Homo erectus,early Homo sapiens,and late Homo sapiens.The Kehe sites group is an important ancient human site found in China.As an ancient human site that was unearthed by early Homo sapiens and late Homo sapiens,it is of great significance to reveal the process of human evolution.Among them,site 6054 of Kehe Site is the site of the first site found,and site 6053 of Xihoudu Site is the earliest discovered Paleolithic paleo-human human site in the Early Pleistocene.Fossil antler fossils with cut marks and cautery traces have also been found at the site of Xihoudu site 6053.This may be the earliest trace of ancient human fire found in China.Since the discovery of the site,many scholars have had a keen interest in the issue of the age and conducted a lot of research.At present,there are conclusions in the study.One is to use the loess-palaeo-soil sequence overlaid on the cultural layer to infer.On the other hand,physical ageing of mammals and shell fossils in the same layer is performed.So far,these research results have not yet reached a consensus on the issue of the age.Therefore,this paper analyzes the formation age of the cultural layer of the site from the perspective of regional river and lake environmental evolution.In order to achieve the research goal,we first need to investigate and analyze the staged history of sedimentation and evolution of rivers and lakes in the area where the site is located.In the field work,the sampling of Xiwangliao-Xiaoyaoke section,Antouli section,Maya section,Weihe village section and Xiwang village section were selected.Based on the loess-paleosol sequence dating method,sample unit magnetic susceptibility,and paleomagnetic dating data of key horizons,the characteristics of geomorphological sedimentary bodies were analyzed to clarify the regions during the Quaternary,especially during the Middle Pleistocene and Middle-late Pleistocene.The phase history of sedimentary evolution of the river and lake environment.The results show that at least 6 large lakes occurred during the developmental accumulation period of S₁₄,S₁₁,S₈,L₆,S₂ and S₁ in the Weihe Basin.Retreat,and in the south of the Zhongtiao Mountain,the Weinan Basin is affected by the uplift of the mountain structure.The evidence of lake retreat can be found at least four times:S₁₄,L₆,S₂ and S₁.After each lake retreat occurs,the lacustrine deposits exposed to the atmosphere receive accumulation of loess-palaeosols,followed by a slow lake invasion process.The vertical profile of the regional geomorphic sedimentary body indicates that ancient lakes have the periodic characteristics of lake retreat and lake intrusion.Through investigating the profile of the excavation of the cultural layer at the site of6054 Kehe site and 6053 site of Xihoudu site,the section of the section can be summarized into three parts:the top of the loess-the accumulation of ancient soil gas,including the profile of cultural layers The fluvial and alluvial deposits,the lower lacustrine deposits and the older Quaternary early-middle strata.The results of the study indicate that according to the susceptibility data,the oldest loess-paleosol zone over the cultural layer of the site of the site of the Kehe Site 6054 is S₂,while the Xihoudu Site6053 site covers the oldest loess layer-The ancient soil strip is S₁₄.The age of the cultural stratification of the Kehe River site 6054 was before the lake retreat during the S₂ period and after the L ₆ lake retreat.The time of the cultural strata of the Xihoudu Site6053 site was before the lake retreat during the S₁₄ period.Based on the average age of paleosols of S₂ paleosol,L₆ loess and S₁₄ paleosols of loess-paleosol sequence,it is concluded that the age of cultural layer at the site of 6054 is 0.25 Ma.B.P.⁰.63.Ma.B.P.,the age of cultural layer at the site of 6053 is more than 1.09 Ma.B.P..