| The remains of glaciers mainly refer to a series of deposits and eroded landforms directly formed during the development and retreat of glaciers.The confirmation and research of ancient glacier remains are of great scientific significance for in-depth analysis of the activities of ancient glaciers in my country and the laws of paleoclimate changes.Liangwang Mountain is located in the southeast of Kunming City,Yunnan Province,with geographic coordinates N24°46'06.3?,E102°55?08.2?,and the highest altitude is 2820 m.It is surrounded by three plateau lakes,Dianchi Lake,Fuxian Lake and Yangzonghai Lake.This paper studies and analyzes the eroded landform characteristics of the Liangwangshan area,the SEM micro-morphology characteristics of the quartz sand in the mixed deposits,the paleoenvironmental characteristics of the mixed deposits(mainly refers to the pollen analysis),and the glacial series,etc.Glaciers appeared in the region during the Quaternary Period,adding new content to the glacier relics at the southernmost tip of China,and providing important reference materials for improving the paleoclimate and paleoenvironmental evolution laws in southern China.This research mainly gained the following knowledge:(1)After investigation and research,the glacial relics preserved in the Liangwangshan area mainly include: blade ridges,horns,ice buckets,glacial troughs,ice boulders,lateral moraine dikes,moraine rocks,and glacier scratches.Using the ice bucket flatness index and trough power function model to quantitatively analyze the remaining glacial erosion landform,it is concluded that the flatness index of the ice bucket roughly ranges from 1.80 to 3.54,and the b value of the cross section of the glacial trough roughly ranges from 1.572 to 1.572 2.259.The moraines are gravel layers of mixed sizes.The gravel lithology is mainly limestone,which is angular or sub-angular,with low degree of weathering and poor sorting.Some moraines formed by glaciation can be found.(2)Through the analysis of the sporopollen in the Liangwangshan area,it is found that there is no fir in the modern Liangwangshan area,while the fir sporopollen appears frequently in some layers of the moraine section,and the fir sporopollen content in some layers can be as high as 12.3%,reflecting that time The climate in the Liangwangshan area is cold,which shows that the Liangwangshan area had the climatic conditions for the development of glaciers at that time.(3)The SEM micromorphological characteristics of quartz sand in the mixed deposits in the Liangwangshan area are mostly sharp edges-sub-edges,sub-ridges,and high-medium undulating quartz sand particles.Through research and statistics,it is found that the iconic micro-morphological features closely related to the genesis of glaciers,such as scratches,adhered fragments and cracks,all appear with a higher frequency,and the frequency of scratches is 8% to 36%;the frequency of adhered debris Between 14% and 30%;the frequency of cracks is between 6% and 22%,and the total frequency of micro-morphological features related to glacier genesis is higher than that of flowing water and wind.Based on the above results,it is confirmed that the genetic environment of the deposits at the Liangwang Mountain sampling site is a glacier environment.(4)From the results of the sedimentary characteristics of the mixed deposits,SEM characteristics of quartz sand,pollen analysis,and quantitative research on erosion landforms,it can be seen that there were glaciers in the Liangwangshan area during the Quaternary period,and some glacier relics remained in the Liangwangshan area.Through the discussion of the ancient balance line of Liangwang Mountain and the comparative analysis with the sporopollen content of fir in Kunming Basin,it can be known that the glacier period of Liangwang Mountain is the penultimate glacial period.By comparing the ice ages with neighboring mountains,it is concluded that the ability of Liangwang Mountain to develop glaciers at this low latitude during the Second Ice Age was mainly due to the global cooling during the Second Ice Age and the local climate produced by the three surrounding plateau lakes. |
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