The Stratum Characteristics And Geological Evolvement In The Northeast Of Keziletage In Xinjiang

The area be studied in this dissertation located at the northeast of Keziletage in XinJiang,it is a part of the west Beishan rift valley structure belt .Beishan rift valley structure belt developed in Talimu land core, it's north neighbour is Nalati-Hongliuhe suture belt and the south one is Dunhuang landmass. Here are a lot of ruptures and magma rocks in the belt.The stratum includes early proterozoic era metamorphic crystal basement,middle proterozoic era sedimented cover layer and later Paleozoic era rift valley sediment.Metamorphic crystal basement-Beishan rock group are stratified but out of order layers, which lava and few juvenility clastic rock were sedimented in shallow sea around or between the early proterozoic era landmass. Main period metamorphism of Beishan rock group is Xingdi period(1800Ma) middle press hornblende facies , the temperature of this facies is 580-680℃,and press is 0.58-0.69GPa. Main period of fade metamorphism is Aerjin period ,its temperature is 350-550℃and press 0.4-0.6Gpa. Nearby 500℃maybe the mostly temperature of Main period of fade metamorphism . In later Paleozoic era , Beishan valley developed from craze to lose , at the same time , lots of volcanoes broken forth and lava up invaded , what makes ground temperature grads hoist, rocks nearby lava occurred contact metamorphic, which produced nondirective biotite . The close of rift valley and Indo-China -The Himalayas period drive effect made intrusive rock to be cataclastic or mylonite.Middle proterozoic era sedimented cover layer-Gudongjing rock group are stratified but out of order layers, which juvenility clastic rock and few lava were sedimented in shallow sea ,its Main period metamorphism is the main period of fade metamorphism of Beishan rock group ,however the temperature and press are a little lower than that of Beishan rock group .There are below Carboniferous system Hongliuyuan group,up Carboniferous system Shibanshan group,Shengli spring group,Ganquan group and middle Permian Luotuogou group sedimented in later Paleozoic era , Hongliuyuan group,Shibanshan group,Shengli spring group,Ganquan group were sedimented when the rift valley drawing opening period for the first time ,and Luotuogou group was sedimented in the second shrinking closing period .