The Study Of Tectonic Evolution Of Late Paleozoic Strata In The East Of Inner Mongolia

The eastern part of Inner Mongolia is lacated in the east of the Central Asia Orogenic Belt which is grippde by north china plate and siberia plate.It is a complex block of many microplates, which closes to west of pacific plate.It is a important part of trench-arc-basin system of Northeastern Asia continental margin. The paper carefully researches deformation characteristics and times of the folds and faults based on the collection and analysis of amounts of data and previous research results. The paper researches the tectonic evolution of Late Paleozoic strata in the study area, and through analysis on the regional tectonic stress field revealed the dynamic context of Late Paleozoic tectonic evolution. The followings are initial understanding:一,Late Paleozoic strata has mainly experienced three tectonic deformation in the study area.1. The first structural deformation of ate Paleozoic strata performaned EW folds and faults. Structure of this period mainly develops in the southern part of the study area, deformation strength increases in the direction of Sylla-lun River collision, there are relatively closed in the folds and thrust faults. As to the stack transformation of NE structure of the second phase, the first structural deformation only reserves in the south of the study area, EW structure have been constructed completely in the majority of the northern region.2. The second structural deformation of late Paleozoic strata performaned NE or NNE wide folds and large strike-slip faults, it has extensive distribution space, and it forms the main structural framework of Late Paleozoic strata. The fold deformation relatively closed near tectonic belt or rock. The period of structural deformation stacked on the early EW structure near Silamulun river collision belt in the southwest, it strongly transformed the early structure. The period of structural deformation often across Silamulun river collision belt and develop on both sides. On the whole NEE fold hub are main in the southwest and it gradually becomes NE to NNE. The period structure was constructed by the third period NW faults, particularly in the northern part of the study area, the NW faults cut and left offset the second phase of NE faults and fold.3.The third structural deformation of late Paleozoic strata is characterized by the NW brittle faults, There are large NW faults and NW outcrop-scale faults in the study area. These large NW faults perform river system cutting Xing'an Mountains in the current landscape, often have the characteristics of left slip and stack on the first two structures. They cut and left offset the early EW and NE structure.二,Regional tectonic setting Of structural deformation Of late Paleozoic strata has been determined in the study area.The North China Plate subducted northward and it inpacted with Jiameng plot, the first phase of EW structural deformation was formed in the context of the fomer squeezing field.The second phase of NE-NNE structure and the third phase of NW structure were under the control of the western Pacific tectonic system, as the Western Pacific Yi Zenai Kawasaki plate obliquely subducted towards Eurasia,the second phase of NE-NNE structure and the third phase of NW structure were formed in the context of NW-SE compresso-shear field in the northeast region. 三,I put forward the preliminary model of tectonic evolution Of Late Paleozoic stratum.After the end of Late Paleozoic sedimentary, north China plate begins to dive towards north and collide with Jia Meng plot.It leads to the first period of deformation of Late Paleozoic stratum and forms EW Fault and fold structure. The closure of Silamulun river splicing tape marks the end of the tectonic system of the ancient Asian Ocean and that the Western Pacific tectonic system begins to control regional tectonic evolution in the northeast region. The Western Pacific Yi Zena Kawasaki plates began to subduct in the Jurassic - the Cretaceous period. It causes the entire northeast region to be NW-SE twisting stress field and forms the secone period of NE-NNE structure.The period of structure stacks on the the first phase of EW structure,and it has a strong transformation for the first phase of EW structure.As the Western Pacific Yi Zena Kawasaki plate continues to obliquely subduct,in NW-SE pressure-twisting field, it begins to form the third phase of NW twisting faults.These stacking NW structure cut the first period of EW structure and the second period of NE structure,and current main structural pattern is formed in the study area.