Tectonic Deformation And Evolution Of Fold And Thrust Belt In South Of Tuo Lai Mountain Are, Qinghai

South of Tuo Lai mountain is located in the uplift of Qilian Mountains which is in thenortheastern margin of the Qinghai-Tibet plateau. Since Cenozoic Himalaya orogenic period,because of the remote effect of the subduction and collision between the India plate andEurasian plate, the Qilian-Nanshan mountains have been shortened, resulting in the stronguplift of the Qilian mountain. And South of Tuo Lai mountain has begun to uplift accordingly.The author conducted1:50000regional geological mapping in the study area, andobtained the crustal shortening rate39.6%,which is calculated by the method of balancedgeological section. Through the structural analysis theory and method, the evolution sequenceof structural deformation in Cenozoic has been established and divided into three stages ofstructural deformation: The first stage of structural deformation developed a series of broadand continuous symmetrical level of upright fold, axial is about285°; The second stage iscontrolled by the left strike-slip faults of west Hill Long and Rimucerxiuma, which destroyedthe level of upright fold, and formed leant plunging fold, axial is about136°; In the last stage,with the increase of NS periodic compressional stress, part of the folds deformed withtectonic superposition effect, axial of these folds is about95°.Meanwhile, in ordered to confirm the above division method. The author studied theplanation surface and obtained three-level planation surface, and confirmed the existence ofthree uplift process, which is correspond to the structural deformation. The first level ofplanation surface is5000m, the second is about4700m, and the last is about4400m.Throughthe analysis of apatite fission track data of Fengle river in the north of the study area. It alsoexperienced three phases of uplift: the first phase from89Ma to31Ma, the second phase from31Ma to8Ma and the last phase from8Ma till now. The last phase experienced the fastestuplift; combined several methods, it can be concluded that Xiarenci-Hill long experiencedthree stages of Cenozoic tectonic uplift which is in accordance of the periodic uplift of Qilianmountain.