Aeolian Accumulation And Their Paleoenvironmental Implication Scince The Late Pleistocene At Nyingchi

Aeolian is dust accumulation formed in a specific Quaternary environment that con-tains rich information about atmospheric circulation and sedimentary environment.Loess is a natural archive for studying regional and global climate changes,and is widely used to reconstruct quaternary climate evolution.The extensive aeolian depos-its in terraces,foothills and mountains of the Yarlung Tsangpo valley in the southern Tibetan Plateau.Therefore,the study of aeolian deposits is of great significance for understanding the environmental changes in the southern Tibetan Plateau.Here,we investigated an aeolian accumulation profile of 7.6 m thickness in Nyingchi area（LZ4 section）.Based on 7 AMS ¹⁴C ages,multiproxies analysis are car-ried out to interpret palaeo-environmental informations.Moreover,the driving mech-anism of the environment in the study area were explored.The aeolian deposit was formed during the period from about 37.6 to 2.4 cal.kyr BP,suggesting that sediments have deposited since the late Pleistocene;The evolution of environment in the Nyingchi area could be divided into six stages:37.6 to 33.8 cal.kyr BP,the summer monsoon was relatively strong,resulting in a warm and hu-mid climate and strong weathering and pedogenesis;33.8 to 30.7 cal.kyr BP,in the cold and dry period,the summer monsoon weakened slightly;30.7 to 26.2 cal.kyr BP,the climate shifted to warm and humid;26.2 to17.1 cal.kyr BP,the climate became cold and dry;17.1 to 14.4 cal.kyr BP,the climate gradually turned warm and humid,the summer monsoon increased,and the soil was relatively developed;During the 14.4 to2.4 cal.kyr BP,the region has experienced a dry and cold-relatively warm and hu-mid-dry and windy climate process.Compare the climatic record of LZ4 with the other records,the rapid climate change events can be identified from the LZ4 profile.The alternation of loess-paleosol was mainly the result of the joint influence of northern hemisphere solar radiation,In-dian monsoon and westerly wind.Therefore,the LZ4 record was not simplely corre-spondingto global climate change,and also influenced by regional factors.