STUDY ON STRUCTURAL STRESS FIELDS SINCE PERMIAN,BACHU AREA,TARIM BASIN

Three periods of structural stress fields can be recognized since Permian in northwest of Tarim Basin and adjacent areas based on structural evolution analysis,which is the end of Permian,the Triassic to paleogene and Neogene.Based on the research of stress-response structures of dykes,joints,slickensides,folds and faults,and analysis of the comparison characters of field of stress,it is found that the direction of the maximum principal stress formed by the collision of middle Tianshan island arc and Tarim basin was NW.The direction of maximum principal stress Triassic to paleogene was NNE,which developed by repression of dextrorotary of Tarim basin.And it was N-S direction since Neogene in Bachu area as a result of the collision of Indian plate with Eurasian plate.Furthermore,the authors simulated the stress field since Neogene based on 2D finite-element method,to deeply analyze the distribution and direction of stresses in the research area.