Glacier Scale And Climate Drivers Of Quaternary Glaciations In Middle Tenasserim Chain

Glaciers are the product of climate change,and the development and scale of glaciers are constrained by climate.Studying the changes of glaciers in the past can deeply understand the law of climate evolution.It plays a key role in studying climate evolution and understanding the history of glacial fluctuations.The middle Tenasserim chain is located in the transition zone from the Qinghai-Tibet Plateau to the Yungui Plateau,and is also on the southwest monsoon channel.During the Quaternary period,the area experienced multiple glaciers,leaving behind rich glaciers.Finding out the distribution law of glaciological relics in the middle section of Tenasserim chain can not only restore the scale of glaciation in the region,but also rebuild the changing climatic conditions of glaciers in the region.This is very important to understand the mechanism of regional glaciers' response to climate change and predict the future trend of glaciers.This article takes the Quaternary glacial relics in the middle Tenasserim chain as the research object,conducts field surveys on the glacier landforms of Juequ,Ruqu,and Quzha valleys,clarifies the scope of glaciation in different periods,and uses the glacial longitudinal flowline model The Degree day model and the glacier flow model reconstruct the glacier scale and the climatic conditions of the glacier development in different periods in the study area.Then explore the climate driving mechanism of each ice advance.Through the study of the above contents,the following conclusions have been initially obtained:(1)From 1988 to 2018,the modern glaciers in the middle part of Tenasserim chain are generally retreating.The glacier area in Juequ Valley decreased by 1.073km~2,and the glacier reserves decreased by 0.051km~3.The end of the glacier retreated about 45 m,and there is a tendency to accelerate retreat.An analysis of the changes in average temperature and annual precipitation between Changdu and Basu weather stations from 1980 to 2018 shows that the rapid heating from 1980 to 2008 is the main reason for the melting of glaciers in the region.The continuous increase in temperature and the reduction in precipitation during this period of2009-2018 are important factors leading to the acceleration of the retreat of glaciers.(2)The glacier area at the penultimate glacial period(MIS 6)in the Juequ trough valley in the middle part of the Tenasserim chain is 196.875 km~2,the glacier reserves are 37.406 km~3,and the average thickness of the glacier is 190m;The area is 161.153 km~2,the glacier reserves are 10.475 km~3,the average thickness of the glacier is 65m;the area of the glacier is 112.346km~2 at the last ice age(LGM),the glacier reserves are 4.831 km~3,the average thickness of theglacier is 43m;The glacier area is 19.491 km~2,the glacier reserves are 0.818 km~3,and the average glacier thickness is 42 m.(3)Set the late Quaternary MIS 6,MIS 3,LGM,and e H precipitations in the middle part of Tanian Thaengshan area to be 60?80%,50?80%,10?50%,50? 80% of modern precipitation respectively.The simulation results show that the ancient temperature is about5.5?6.5?,3.5?4.5?,3.5?5.0?,1.5?3.0?,respectively.It shows that the penultimate glacial period(MIS 6),the last glacial period(LGM)and the early Holocene(e H)are mainly driven by the development of glaciers in the low temperature environment,while the mid-last glacial period(MIS3)is a combination of abundant precipitation in the low temperature environment Together drive the development of glaciers.