Evidence And Environmental Background Of The Prehistoric Human Activities In The Basins Of Qinghai Lake And Siling Co

The history of prehistoric human activities on the Qinghai-Tibet Plateau and its relationship with climate and environmental change is one of the more concerned issues in international earth environmental science,paleoanthropology and archaeology.At present,there have been many breakthroughs in the study of prehistoric human activities and their environmental background in this alpine region,but research on the following points is still relatively lacking:?1?The spatial distribution of prehistoric human activity sites on the plateau has been unbalanced,and the sites in the high altitude area and its hinterland of the plateau?>3500 meters?are sparsely distributed;?2?There are few reports on the discovery and dating of the native strata of the cultural heritage of the hunting population in the high-altitude area of the plateau.There have been no reports of stable isotope tracing studies on domestication of domestic animals in this area;?3?There is no more information about the changes in the habitat environment related to ancient human life in the study of the relationship between ancient people and land.Therefore,it is urgent to further study the relationship between ancient people and land in this high-altitude area.Qinghai lake and Siling Co are the two largest lakes on the Qinghai-Tibet Plateau.They must be important areas for ancient human activities for rich in water sources and food resources for human survival.Before the emergence of agriculture that provided a stable source of food,it was a suitable area for ancient humans to live and/or domesticate animals at high altitudes on the plateau.This paper takes the cultural relics unearthed from the sites of Qinghai Lake Basin?GLM?SS and DC?and Siling Co Basin?LD?and the lake swamp profile of Qinghai Lake Basin?LYG?as the research object.17 bone samples,15 organic matter samples,2 plant residues and 1screw shell sample were collected at four sites for carbon dating.In addition,the test and analysis of environmental substitution indicators such as loss on ignition,chromaticity,magnetic susceptibility and XRF core scanning were carried out on the lake swamp profile of the Qinghai Lake Basin and the cultural profile of the Siling Co Basin.Combined with the relevant site data and climate and environmental indicators published in the study area,we analyzed the way of life and environmental background of the prehistoric human activities in the key lake basins of the Qinghai-Tibet Plateau.The main conclusions are as follows:1:In the three prehistoric sites of Qinghai Lake Basin?GLM?SS and DC?,204samples of animal bones and teeth were systematically collected,and 64 samples were identified.Through the AMS ¹⁴C dating based on Capra collagen,it was found that the human activities time of GLM,SS and DC sites were 8.5 Cal ka BP,6.9-6.1Cal ka BP and 3.7-3.5 Cal ka BP,respectively?a represents the year,Cal represents the age of correction for 14C,BP is the date,and today it is calculated from 1950 a?.The?¹³C_collage?Collagen carbon isotope?,?¹³C_apatite?Apatite carbon isotope?and tooth series?¹³C_apatitepatite both reflects that the protein diet,the overall diet and the seasonal diet of Capra in Qinghai Lake Basin are mainly supplied by C3 plants,and there is no signal that ancient people used C₄ grains to supply Capra.2:Detailed photographing,measurement,classification and statistical work were carried out on 840 stone products unearthed in the native stratum of LD?Lingdong?in Siling Co Basin.391 stone tools and 449 unmodified stones were collected from in-situ sediments of 0-40 cm depth,which are classified in five categories:33 cores,199 flakes,27 blades including microblades,and 132 stone tools.Among 132 stone tools,104 scrapers,25 crude products,and 3 points were identified.Among 33 cores,10?3,2?2,and 4?cores,and 2 microcores,9 wedge-shaped,1 boat-shaped,1cylindrical,and 1 semi-conical microcores,and 3 levallois blade cores were identified using the criteria by Toth?1982?and Wei?1994?.7 AMS ¹⁴C and 2 OSL?photoluminescence?dating established the LD site age range of 6775-390 Cal a BP.This shows that the technical adaptability advantages of fine stone leaves and fine stone tools helped ancient hunting humans to live in the Siling Co Lake Basin with high risk of high-altitude hinterland resources in the plateau at least in the middle of the Holocene.3:The Qinghai Lake Basin and Selincuo Basin prehistoric?3.0 ka BP ago?ancient human hunting and survival patterns are rich in color,and the signs of agricultural development are not obvious.According to the 75 ¹⁴C data of 21 sites since 15 ka in the Qinghai Lake Basin,the Summed probability distribution of calibrated radiocarbon dates of archaeological sites in the Qinghai Lake Basin can be used to reflect the changes in human activities at the basin.The paleoenvironmental results of environmental quality indicators such as organic matter,brightness L*and Rb/Sr ratio in the LYG section of Qinghai Lake Basin show when the climatic and environmental conditions in the Qinghai Lake area are suitable,the frequency of ancient hunting crowds increases.The data analyzed in this study complements the organic carbon and nitrogen isotope data sets of animal bones since the Holocene in the Qinghai Lake Basin,and fills in the blanks of inorganic carbon and oxygen isotope data of animal bone apatite since the Holocene in the region.For the first time,the stable carbon and oxygen isotope values of Capra enamel sequences on the Qinghai-Tibet Plateau were used to refine the seasonal changes in the supply of plants.Relevant environmental indicator data were extracted from the peat sedimentary profile of less than 10 km from prehistoric human activities,which more accurately reflected the climate and environmental information of prehistoric human activities,providing direct evidence for studying the background of prehistoric human activities.LD is the first site that has been discovered in the hinterland of the plateau at an altitude close to 4,600meters above sea level with native stratigraphic information and continuous mid-to-late Holocene hunting crowds.We believe that the appropriate climatic environment in the middle Holocene on the Qinghai-Tibet Plateau and the"advanced"microlithic technology complement each other,prompting the high altitude area of the Qinghai-Tibet Plateau to become a gathering place for microlithic hunter collectors.This provides a reference forenriching the research on the evolution law and model of the relationship between ancient people and land in the high and cold regions.