Cenozoic basin structural differences of Jiyang depression and its formation mechanism
Zhang Kuihua1,2, Xue Yan2, Wu Zhiping1, Nie Wenlong3, Hu Jiashan2
1. School of Geosciences, China University of Petroleum, Qingdao 266555;
2. Western Department, Research Institute of Exploration and Development, Shengli Oilfield Company, Dongying, Shandong 257015;
3. Research Institute of Oil Engineering and Technology, Shengli Oilfiled Company, Dongying, Shandong 257000
In order to investigate the basin structure spatial-temporal differences of Jiyang depression and its dynamical mechanism, the present basin structure and its Cenozoic structural evolution process were analysed in detail by use of fault activity analysis, balance profile restoration and stretching rate statistics. Then the differences were analysed by "structural differences inside sags"-"structural differences between sags"-"regional structural differences" three levels, and the formation mechanism was discussed. The results show that the differences inner and between the sags were mainly controlled by the different development of pre-existing NW faults and the main fractures in different evolution stages. Otherwise, controlled by the subduction direction changes between Pacific-oceanic plate, Indian plate and Eurasian plate, the movement of Tan-Lu fault zone changed from left-lateral strike slip to right-lateral strike slip. At the same time, deep-seated mantle material experienced a change from upwelling to sinking. The combined action of the above caused regionally structural transformation of Jiyang depression.