The Formation And Evolution Of Jing Peng Palaeo-lake,hexigten,Inner Monglia

Palaeo-JingPeng lake,which has been got great attention of scholars at home and abroad,located in Inner Mongolia Hexigten and in the southwest side of Daxinganling Mountains,nearby the arid and semi-arid and sub-humid climatic boundary.This paper,taking Palaeo-JingPeng lake sediments as the research object,based on predecessors' research,through many field investigations and uses A variety of indoor analysis,such as the method of Sedimentology and stratigraphy,chronology,and remote sensing,systematic and intensive to discuss the formation and evolution of palaeo-Lake,and relation between the ancient lake evolution and the development process of Xilamulun River.The study shows that:1.The research area is located in the upper of Xilamulun River,which has rich river terrace,the development of the water system,and The large difference of terrain.Generally there are 5 to 6 river terraces.The terrace type is based on rock-seated terrace and the accumulation terrace,and the few visible erosion terraces.Different sections of the river have different Valley landscape.2.Comprehensive analysis of the lacustrine sedimentary section feature,we find that Palaeo-JingPeng sediments distributed in the two shores for the upper of Xilamulun River.There are distributed of dendrites in the plane,and the distribution area is about 232 km 2.The highest elevation of the lacustrine sediments is between 921 and 1120 m,and the sediments are different from different river sections.3.Age data measured before and previous materials showed that the age of the Palaeo-JingPeng sediments is between 11 and 34 ka,and the time span is from Q_p^3-3 to Qh1,with deposit age of about 23 ka.4.According to the geologic features of the study area and the characteristics of typical deposition profile,we tentatively suggest that the Palaeo-JingPeng lake is an ancient quake lake which The cause likely due to seismic activity and others caused landslides or debris to blocked river bed that the upper Xilamulun River water accumulated for lake.5.Tectonic movement,climate change and water network changes these three factors play an important role in the process of evolution of the Palaeo-JingPeng lake.