The Ancient Glaciers Research Of Climate And Tectonic Movement Coupling Relations Of Luoji Mountain

Mount Luoji belongs to the eastern Tibetan Plateau, located in southwesternSichuan mountain, east of the Anning River valley, west of the Qionghai-large Qingliangzi-Pugh off depression Valley, which is one of the regions that has the ancientglaciation but no modern glaciation in eastern China, it is significant to study thedevelopment condition of paleo-glacier as well as the evolution of tectonic andclimate. With the methods that field investigation, sampling and sediment analyzing,sediment grain size characteristics and environmental magnetism were studies indetails. Combined with the ELA, recover the temperature and precipitation conditions.According to studying the relationship between environment revolution includingclimate change and tectonic uplift, we believe that the Luoji mountain once developedlarge-scale and relatively well-preserved temperate glacial landforms of every stage.According to analyzing the grain size characteristic and magnetic susceptibilityof the sediments in the study area, we find that grain composition of moraine belongsto different periods show little difference, the average particle size of the sedimentschanges between-0.55and2.233Ф and has the average of1.3709Ф, the average of1.5867Ф and1.4532Ф respectively corresponding to penultimate glacial cycle and thelast glacial cycle, due to the impact of tectonic movement in the penultimate glacialcycle that the average size of moraine is larger than in the last glacial cycle, indicatingthe extent of the glaciers at that time is large. The frequency magnetic susceptibility isbetween0.8%and6.88%, and the average value is3.75%, all these index show thatthe climate in last glacial cycle is dry and cold as well as weak pedogenesis. Theaffected factors on the glacial deposit are not only the mother lithologic, but also thecomplicated climate conditions.According to calculating the ELA, we can conclude that the modern theory ELAof Mount Luoji is5103±200m, the pale-ELA in Neoglaciation, the late and the earlystage of the last glacial cycle, penultimate glacial cycle and the antepenultimateglacial are respectively corresponding to4044m,3984m,3842m,3694m and3430m.Compared with adjacent mountains in glaciations positive and negative sent atdifferent stage, together with the development of the cirque, we find that the tectonicuplift of the mountain has impact on not only ELA, but also glacial landforms atpenultimate glacial cycle and the antepenultimate glacial. The bordering mountains ofeastern Tibetan Plateau is intensively influenced by "Gong he Movement", which result in local uplift, there is a complex relationship among mountain uplift and localtectonic movements together with climate change.