Mesozoic inverted structure analysis of the southern margin of the Junggar Basin
Wang Tianbao1, Jia Dong1, Wei Dongtao2, Wang Yanjun2, Li Yiquan1, Zhang Han2
1. Institute of Energy Sciences, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093;
2. Research Institute of Petroleum Exploration & Development-Northwest, PetroChina, Lanzhou 730000
The dynamic of the first-order fold-thrust belts were modeled by the combination of the numerical modeling and balanced cross-section techniques,with the constraints from the outcrop,well drilling and logging data.Moreover, 94 seismic sections collected from southern margin of the Junggar Basin were analyzed with the fault-related fold theory.The results indicate that the Junggar Basin showing extensional conditions with the development of the Kalazha and Changji normal faults from the Middle Triassic to Middle Jurassic.This tectonic frame was in charge of the sedimentary characteristics; the switch of the stress field from the extension to compression occurred in the Middle-Late Jurassic.As a result of this switch,normal faults developed earlier reversed to reverse fault(Qigu fault)and controlled the initial development of the first-order anticlines.Meanwhile,the initial from of the Qigu and Changji anticlines developed; The Qigu,Changji and Kalazha anticlines finally shaped with the strong compression.