Climate Change Since 16 Ka BP In The Northern Margin Of Tarim Basin And Its Impact On The Evolution Of Civilization

Southern Xinjiang is located in the hinterland of Eurasia and belongs to a typical inland arid area.The oasis that widely exists in the edge of the desert and between the mountains forms a natural corridor,which provides a good environmental foundation for the development and exchange of culture,making it a bridge between Eastern and Western cultures.The development of human culture in this area is extremely dependent on the natural environment,and the rise and fall of culture is closely related to it.Therefore,this article attempts to study the climate change in the northern margin of Tarim Basin in southern Xinjiang and its impact on the environment,and then explore its impact on the cultural evolution of the region.Through the magnetic parameters of the Kansu section(magnetic susceptibility(?_lf),frequency magnetic susceptibility(?_fd),non-hysteretic residual magnetic susceptibility(?_ARM),saturated isothermal residual magnetization?SIRM?,"hard"residual magnetization?HIRM?),analys is of indicators such as granularity and chromaticity,selecting appropriate climate substitute indicators,and combining with photoluminescence dating?OSL?to establish a reliable chronological framework,thus rebuilding the history of climate change since 16 ka BP in the northern margin of Tarim Basin.In addition,the age samples of the sites in the study area were determined by AMS¹⁴C,combined with previous studies,the ancient cultural sequence in the southern Xinjiang region was established and improved.The main conclusions are as follows:?1?The magnetic minerals in the sediments of the Kansu section are mainly ferrimagnetic minerals,and contain a certain amount of incomplete antiferromagnetic minerals from the dust source area,and the concentration of magnetic minerals is relatively low.The nanometer-sized ferromagnetic minerals formed by soil formation contribute greatly to the susceptibility.The size of magnetic minerals is relatively coarse,mainly composed of multi-domain?MD?,pseudo-single domain?PSD?and coarse-grained stable single-domain?SSD?.The sediment particle size is mainly composed of silt,followed by clay,with the lowest content of sand,which is a typical aeolian depos it.Luminance?L*?can reflect the process of weathering and soil formation related to hydrothermal conditions and soil development degree,and is sensitive to climate and environmental evolution.?2?Using the parameters L*,?_fd,?_ARM/SIRM,clay component?<2?m?and sand component?>63?m?as climatic substitute indicators,the climate evolution process in North margin of Tarim Basin since 16 ka BP was revealed,The climate as a whole tends to become wet,which can be divided into the following four stages:the climate is generally arid but tends to become wet during the 16-12 ka BP stage;the precipitation increases and the soil development increases during the12-4 ka BP stage;during 4-2 ka BP,the climate continued to get wet,the wettest climate was around 2000 ka BP;2-0.5 ka BP at this stage,the climate was relatively dry,precipitation decreased,and the intensity of soil development was weakened.?3?Climate change has a decisive influence on the evolution of civilization in North margin of Tarim Basin.16-12 ka BP corresponds to the Paleolithic period,with fewer sites and more scattered distribution,which is related to the relatively arid climate in the early Holocene;12-4 ka BP is the Microlith Age,the Neolithic sites in this period were missing in North margin of Tarim Basin,and the large number of fine stone age sites in the later period is consistent with the humid climate change in the earlier period and the later dry period;4² ka BP is the Bronze Iron Age this period,the culture and the surrounding Eurasian continent and eastern inland areas were exchanged and developed.The number of sites has increased sharply,the business model has changed,and the culture has ushered in a great integration.It has been supported by the humid climate conditions during this period;since 2 ka BP,during the historical prosperity of the Han-Tang Silk Road in the historical period,North margin of Tarim Basin has experienced a decline in culture,which also is in line with the gradual drying of the climate during this period.