The Preliminary Study On The Quaternary Glacial Landforms And Glacial Age In The East Slope Of Xiao Xiangling Mountain,Sichuan

Xiaoxiangling is located at the eastern margin of Hengduan Mountains,above 2300 m above sea level to preserve the exact Quaternary glacier relics.Depth study of the Quaternary glaciers in the region of the geomorphic features,glacial series,moraine composition and source,which will not only help to explore the basic characteristics of the Quaternary glacier development in the Hengduan Mountains,but also provide geomorphology and chronology support for global environmental change research.The main peak and adjacent area of the east slope of Xiaoxiangling mountain in the Panxi Plateau are the key research areas,and the methods of field analysis,experimental analysis and age determination are used.The main purpose of this study is to restore the evolution history of glaciation in the region and to explore the influencing factors of controlling glaciation.The main conclusions are as follows:(1)Glacier erosion geomorphology: The Xiaoxiangling area is formed by a Quaternary glacier to form a complete glacier eroded geomorphology-horn,ridge,ice bucket and glacier trough.Dongpo is a typical ice bucket landform,the ice bucket mainly toward the northeast,southeast,most of the empty bucket,the bottom of the bucket and the exit at the very little or no morain.According to the shape of the bucket and the bottom of the ice bucket elevation from top to bottom can be divided into three levels: the bottom of the ice at an altitude of4055-4120 m for the first level,the bottom of the ice at an altitude of 3942-3953 m for the second level,ice Fighting at altitudes between 3703-3710 m for the third level.Glacier trough development of large numbers,the impact of the mountain to show the east and west,most of the glacier trough shape integrity,for the U-type.(2)Glacier accumulation of landform: There are three clear formations of moraines distributed in the glacier troughs of the east slope of Xiaoxiangling,the main elevation is2300-3500 m,the lateral moraine develops the largest and the inner moraine is shorter.In the same valley,the shady slope side of the moraine embankment than the sunny slope of the lower and lowe distribution.The lower limit of the distribution of the high-side moraine is2300 m and the lower end of the low-lying moraine is 2620 m.The third set of moraines distributed in the bottom of the valley upstream to the shape of the arc-shaped moraine ridge preserved,blocking the flow of water to form the moraine lake.Through the field topography method,laboratory sedimentology,geochemical element analysis,combined with ESR data,it is concluded that there were three ice events in the study area since the Quaternary period.The age of the formation of the high gaolin in the long trench is roughly 135.3-199.6 ka,which is developed in the penultimate ice age(MIS 6),the low side moraine is 73.6-80.8ka(MIS 4),the bottom of the valley is the youngest,For the last ice age(MIS 2)product.(3)Experimental analysis of indoor sediments: Sediment composition in the Xiaoxiangling area is dominated by sand,and the distribution of moraines is poor,indicating that the overall glaciation is small in scale.The content of coarse sand and medium sand in the first glacial period was higher than that in the second glacial period,indicating that the first glaciation was stronger than the second glaciation.There are differences in the parameters of the sediments of the two samples separated by a certain distance from the same section,indicating that the depositional environment of glacier is complicated.The comprehensive analysis of the chemical elements of the moraine shows that the sediments of the Xiaoxiangling have obvious characteristics of the glacier sediments,and the weathered degree of the high side morals is higher than that of the low side morals.(4)The tectonic uplift and favorable temperature and precipitation conditions of the glacial stage jointly control the development of the Xiaoxiangling glacier and promote the occurrence of ice entering the various stages.