Research On The Cenozoic Uplift Law In The Middle Section Of Altun Tagh Fault

The Altun Tagh fault zone in the northern part of the Qinghai-Tibet Plateau is more than 1,600 kilometers long,and divides the Qinghai-Tibet Plateau,which has a softer lithosphere hardness,and the Tarim Plate,which has a harder lithosphere,into two parts.Relevant research on this fault zone will be a hot topic in the geological community for a long time,and the debate on it will always exist.The research on the Altun Tagh fault zone has achieved fruitful results,but the studies on the Cenozoic activities of the Altun Tagh fault zone including the start time of deformation are not very in-depth.There are still different understandings in many aspects,and more field research results are needed.Support related theories.Based on extensive field geological surveys,this paper focuses on stratigraphy and isotopic chronology and other research methods,combined with the Cenozoic sedimentary stratigraphic distribution and lithofacies combination changes in the Qaidam Basin.The Cenozoic uplift time and uplift characteristics were systematically discussed,and it was proposed that the Altun Tagh fault had multiple thrust-strike-slip-up movements in the Cenozoic,inferred the geological age of its specific activities,and discussed the Altun Tagh fault The uplift evolution of the belt.(1)The change of Cenozoic stratigraphic distribution and lithofacies combination shows that the Cenozoic(from Lulehe Formation to Shangyoushashan Formation)on both sides of the Altun Tagh fault zone is similar in lithofacies combination and has good stratigraphic consistency,belonging to the unified Cenozoic In sedimentary basins,the activity of the Altun Tagh fault zone in the early Cenozoic was weak,and the activity gradually increased from the Shizigou Formation period and thereafter.(2)Evidence from chronology shows that the activity of the Altun Tagh Fault has obvious phases.The Cenozoic uplift was dominated by strike-slip and squeeze.The uplift activity continued to strengthen and reached its peak in the Quaternary.The gold fault zone is still in the stage of continuous uplift.During the Cenozoic period,uplift occurred in the Altun Tagh Mountains as early as 48 Ma.After 16Ma,the left-lateral strike-slip phenomenon of the Altun Tagh Fault began to appear.(3)Evidence of apatite fission track verified the uplift and erosion process of the Altun Tagh fault in the Neogene.The Altun Tagh fault before 17Ma was in a relatively stable stage,17Ma-9Ma was in a rapid uplift stage,and the Altun Tagh fault was around 5Ma Uplifted to the surface,dividing the Tarim Basin and Qaidam Basin.(4)Through research,it is believed that the Altun Tagh fault has experienced complex development and evolution in a long period of time,and has re-uplifted during the Cenozoic period.Its Cenozoic uplift evolution is mainly divided into four stages:the Paleocene-Late Eocene period,the Tarim Basin and the Qaidam Basin are connected together,the Altyn Tagh Mountains have not yet begun to uplift,and the fault activity is weak;in the late Eocene-Middle Miocene,the Altun Tagh fault began to be weakly uplifted,the initial uplift was not large,and the Miocene uplift was the most intense;During the late Miocene-Pliocene,the uplift of the Altun Tagh Mountains decreased,and there were more piedmonts.The sedimentary range of the original basins in some areas extended westward from the Altun Tagh Mountains.The overall uplift and rapid uplift of the Qinghai-Tibet Plateau eventually became the present form.