Prehistoric Human Activities And Survival Strategies In The Tongtian River Basin

The Qinghai-Tibet Plateau,with its high altitude,cold climate,and oxygen deficiency,presents a formidable challenge for human survival due to its harsh environment and scarce biological resources.However,extensive evidence of ancient human remains found across the plateau confirms a long history of human activities in the region.Therefore,exploring the past human-environment relationships on the Qinghai-Tibet Plateau is crucial for understanding and comprehending human survival patterns and adaptation mechanisms in extreme environments.The Tongtian River Basin,located at the heart of the plateau,serves as a typical area for extreme environments and a crucial zone for humans to adapt to the plateau.Studies on prehistoric human activities and survival strategies in this basin present a scientific significance.In recent decades,significant progress has been made in research on human-environment relationships on the Qinghai-Tibet Plateau,deepening our understanding of human adaptation to the plateau,which was formerly hindered by the harsh natural environment and limited archaeological materials.However,research on prehistoric human activities,environmental backgrounds,survival strategies,and connections with adjacent regions in the Tongtian River Basin remains limited.This study focuses on the newly discovered archaeological sites of Laodaqiao（LDQ）and Daiqu（DQ）in the Tongtian River Basin,along with selected profiles and human activity remains found at these sites,299 lithic artifacts,five charcoal samples,15 optically stimulated luminescence（OSL）samples,and 207 environmental samples as research materials.Methodologies employed include lithic typology analysis,AMS¹⁴C and OSL dating,pollen,fungi,charcoal,grain size,color,total organic carbon（TOC）,geochemical elements,and lipid residue analysis.Additionally,existing research findings are systematically reviewed to elucidate the prehistoric human activities and reconstruct long-term environmental backgrounds in the Tongtian River Basin.Furthermore,the Qinghai-Tibet Plateau Environmental Index（LEI）is constructed using Geographic Information Systems（GIS）based on a geographically weighted regression model.The migration route of prehistoric populations on the plateau has been simulated using a flow of traffic accumulation model.Through a comprehensive analysis of these results,the study explores the historical evolution of human-environment relationships in different stages of prehistory in the Tongtian River Basin and elucidates their adaptation strategies.The main findings of this research are as follows:（1）The constructed Qinghai-Tibet Plateau Living Environmental Index（LEI）scores range from 0.367 to 4.387.The LEI was divided according to the degree of environmental suitability for living on the plateau.The results indicate that the Tongtian River Basin exhibits diverse and complex living conditions,encompassing areas classified as extremely poor,relatively poor,and moderate for survival.Specifically,both the LDQ and DQ sites are situated within zones characterized by relatively poor living conditions.The simulation of prehistoric human migration routes identified seven routes,covering a combined distance of 1486 km.The Tongtian River valley serves as the main artery,with secondary routes branching off in the eastern and western directions.The LDQ and DQ sites are strategically located at pivotal points where the secondary routes intersect with the main artery,indicating their advantageous positions for transportation and communication.（2）The lithic typology and OSL dating results from the LDQ site suggest that the production of core-flake lithic tools using the hard-hammer percussion technique occurred between 15.0 and 11.0 ka BP.Additionally,distinct peaks in the concentration of charcoal particles of different sizes in the LDQ1 and Zhongda profiles around 11.0 to 10.0 ka BP indicate the occupation of the region by core-flake lithic tool-using populations during 15.0 to 10.0 ka BP.According to the AMS14C and OSL dating results from the DQ site,it is suggested that the microlithic hunter-gatherers may have arrived in the Tongtian River valley as early as 9271±143cal a BP.Moreover,considering the peak concentration of charcoal particles（>100μm）in the LDQ1 profile around 5.0 ka BP,along with the upper lithic chronology of the LDQ1 profile and previous findings,it is inferred that the microlithic tool-using population was active in the basin from 9.2 to 4.8 ka BP.Synchronous peaks in charcoal and coprophilous fungi concentrations were observed in the LDQ1 profile,from 4.8 to 2.0 ka BP,coupled with an increase in the number of sites discovered during investigations,indicating extensive human activities in the region during this period.（3）According to the reconstructed paleoenvironmental sequence of the Tiantian River basin,it can be inferred that the climate fluctuated as follows:From 13.2 to 11.8ka BP,the climate exhibited cold and arid characteristics,with low vegetation coverage,strong wind,and sand activity.The vegetation consisted mainly of alpine desert grasslands,with overall low biological productivity.From 11.8 to 7.4 ka BP,wind activity on the plateau interior weakened,leading to favorable environmental conditions,and the alpine meadow vegetation developed.Forests began to grow in some areas,and rich vegetation coverage and concentration of total organic matter were detected during this time.From 7.4 to 1.0 ka BP,the climate shifted towards dry and cold conditions.Wind intensity increased,and dust storms became frequent,causing the vegetation to transit from alpine grasslands to alpine deserts,resulting in lower vegetation coverage and biological productivity.（4）The stone-core and flake technology population during 40.0 ka BP in this region mainly subsisted on animals such as sheep,horses,and deer.The core and flake lithic population engaged in exploration activities in the Tiantian River basin during 15.0 to 10.0 ka BP.By comparing with other sites from the same period,it is inferred that these people mainly consumed large and medium-sized mammals such as wild yaks,donkeys,and deer.The microlithic people in the basin preferred to conduct activities in the valleys with convenient transportation,abundant resources,and favorable living conditions during 9.2 to 4.8 ka BP.Lipid residue analysis indicated that historical people primarily consumed non-ruminant terrestrial animals,such as plateau pikas,groundhogs,and Tibetan foxes.Human activity in the Tiantian River basin significantly increased from 4.8 to 2.0 ka BP.There was a differentiation in subsistence strategies with altitude.In areas with harsh living conditions,the economic mode of the population gradually shifted from hunting and gathering to a nomadic economy,while the agricultural economy component strengthened in the low-altitude river valleys with relatively moderate living conditions.（5）Prehistoric human activity in the Tiantian River basin underwent a process from intermittent exploration to repeated occupation of the area and decreased mobility.Climate fluctuations,living conditions,and accessibility of transportation had a significant impact on the activities of hunter-gatherers but relatively less impact on agricultural populations.After the Holocene,technological advances,cultural expansion,and changes in subsistence patterns enabled ancient humans to adapt more actively to the extreme environments of the plateau.