Spatiotemporal Characteristics And Environment Of Quaternary Glacier Deposits In Middle Tenasserim Chain

The Quaternary glacial sediments contain a certain amount of environmental change information,which is of great significance for studying the evolution characteristics of the climate environment in different periods.He read that the middle section of Weng Mountain is located in the western part of the Hengduan Mountains and preserves good Quaternary glaciers.In this paper,he studied the glacial sediments in the middle section of the Wengshan Mountains,using a combination of field geomorPHology investigation and laboratory test analysis,using optical luminescence?OSL?and electron spin resonance?ESR?dating methods for the ice age.The series was initially divided.Through the environmental indicators such as particle size,geochemical elements,mineral analysis,magnetic susceptibility and loss on ignition,the Quaternary glacial sediment characteristics under different time and space conditions in the study area were analyzed in depth.The results display that:?1?The OSL dating combined with the ESR dating results of glacial sediments in the region,the glaciation occurred at least four times during the Quaternary period above 4200m above sea level in the study area,followed by the Holocene/small ice age in the Holocene/small ice age corresponding to the deep sea oxygen isotope?MIS=marine oxygen Isotope stages?,the last ice age?LGM/MIS2?,the last ice age?MIS3b?,the penultimate ice age?MIS6?.?2?The overall sedimentary characteristics of glacial sediments are mixed in size,no bedding,no sorting,and the degree of weathering is weakened from the MIS6 to the MIS1.?3?The statistical analysis of glacier sediment size in the study area?2mm showed that the average particle size?Mz?was 176.78?m,the grain size composition was dominated by sand?72.72%?,followed by silt?25.29%?and clay?1.98%?.),the average particle size of the hail is 145.11?m,the sand content is 67.02%,the sand is 30.35%,the clay is 2.63%;the ice water sediment has an average particle size of 224.29?m,the sand grade is 81.28%,and the silt is 17.71%,the clay was 1.01%.The fine-grained part mainly exhibits bimodal or multi-peak on the particle size frequency curve,reflecting that the material source of the sediment is complex and the dynamic formation is diverse.The average particle size of the hail is spatially smaller than the source of the glacier.The smaller the particle size,the more the glacier is affected by the intensity of the glacier and the length of the weathering.?4?The magnetic susceptibility of glacial sediments is 8.72×10^-8m³·kg^-1298.00×10^-8m³·kg^-1,and the average value and fluctuation range of volcanic sediments are larger than that of glacial deposits.The size fraction of the concentrated distribution of magnetite is similar to that of ice water sediment.?5?Geochemical and mineralogical index reaction The overall characteristics of the paleoclimate in the study area are cold and dry.The climate is the most dry during the last ice age.The climate is relatively dry during the last glacial period,and the precipitation is increased relative to the last ice age.The ice-water sediment profile in the middle of the last glacial period of the Qufu trough can be divided into three stages.The weathering effect of the stage 1 is strong,and the climate is warmer and moister than the general characteristics of the 2nd and 3rd stages;the stage 2 weathering and temperature and humidity The conditions are general;the weathering effect of stage 3 is the weakest,and the climate is colder and drier than that of stages 1,2.The penultimate ice age precipitation is more than the last ice age and the last ice age,but the temperature is lower.