The Study Of The Development Process About Quaternary Fluvial Geomorphology In Northern Margin Of Tengger Desert Alxa Area

The subjects of this study is fluvial geomorphology which is located in northernmargin of Tengger Desert Alxa Area of Inner Mongolian Autonomous Region.There isimportant guide for palaeoenvironmemtal reconstruction by researching of fluvialgeomorphology development process.Based on the achievements of former research,the study uses the theory of thegeomorphology,Quaternary geology,palynology to analyze the characteristics ofoutcrops and samples which are eventually serve to study the river terraces,floodplains, pluvialin terraces in the study area.Combination of Climaticcharacteristics and neotectonic movement characteristics which reflected in thedrilling pollen data and remote sensing image.Finally established fluvialgeomorphology development process.Determine Eight formative stages of river terraces:they were1200-1300kaBP,145-150ka BP,75-85ka BP,30ka BP,12-14ka BP,8-9ka BP,6-7ka BP,4-5ka BP.According to this,the development process about Quaternary fluvial geomorphologydivided into three stages:Incising fast to become valleys between Early Pleistoceneand the middle stage of Middle Pleistocene;Incising slowly to become valleysbetween the late stage of Middle Pleistocene and the late stage of LatePleistocene;accumulating in the valleys between the early stage of Holocene and themiddle stage of Holocene.