Research On The Uplift And Denudation Process Since The Late Mesozoic In The Northern Part Of The Great Khingan Mountains

The Great Kingan Mountains are located in the eastern part of the Central Asian orogenic belt between the Siberian craton and the North China Craton.Since the Mesozoic,the closed orogeny of the Mongolian-Okhotsk ocean in the north and the subduction of the Pacific plate in the east have affected the tectonic evolution of northeast China.To delve into the uplift process of the greater hinggan mountains and mechanism,this article selects the northern section of greater hinggan mountains as the research object,using apatite fission track,combining with the analysis of tectonic geomorphology of the northern section of the greater hinggan mountains were studied,analysis the greater Kingan mountains uplift period of time and in space,time and intensity differences,reveal the greater hinggan mountains uplift denudation process.Arc Gis was used to analyze DEM data in the study area,and the elevation of the study area ranged from 64 m to 1532 m.According to the degree of relief,the northern part of the Greater Khingan Range is mainly hilly,with the overall slope ranging from0 ° to 25°.The Hypsometric Integral shows that the whole basin in the northern part of Greater Khingan is in the old age stage,and four regions are in the transition stage from prime age to old age.The topographic strip section shows that there are three planation planes in the study area: the elevation of level ? planation plane is about 1400 m,and the elevation of level ? planation plane is about 1200?1300 m.The elevation of level ?planation plane is about 1000?1100 m.According to the cooling rate and the variation degree of the cooling rate,the uplift process of the northern Great Kingan Mountains can be divided into four stages and 11 tectonic events.The first stage is 135?104 Ma,and there are two tectonic events,which may be related to the continental interior debasement.The second stage was 104?65 Ma,and there were 6 tectonic events.The first stage was related to the closure of okhotsk sea,and the other stages were mainly caused by the Pacific plate and tanlu fault.In the third stage,the overall uplift and cooling of 65?23 Ma were slow and quiet,and jiayi fault of northern of Tanlu fault was in a state of tensioning and torsion,which could not transfer the remote effect of the Pacific plate to the Greater Hinggan Mountains.The fourth stage,23?0 Ma,has three tectonic events,which are mainly related to the activity of Pacific plate and Tanlu fault.The study area of 90?23 Ma is in planation state.It is speculated that the present Great Kingan Mountains is the result of uplift since 23 Ma.Based on the correlation analysis between HI value and temperature difference of thermal history samples since23 Ma,it is found that Pearson coefficient value increases gradually between 7 ma and0 Ma,and the correlation increases gradually,which contributes the most to the formation of neogene tectonic geomorphology.Three planation surfaces may be related to 23?17 Ma,9?5 Ma and 5?0 Ma tectonic events.