Meso-Cenozoic Tectonic Stress Field Numerical Simulation On Both Sides Of Yi-Shu Fault Zone

Choosing both sides of Yi-Shu fault zone,Jiaolai Depression and Western Shandong,as the target, this paper researches the numerical simulation of the tectonic stress field by analyzing the characteristics of geometry and kinematics and tectonic evolution in a same tectonic environment.The Jiaolai Depression experienced multi-stage tectonic evolution history and formed a complex structural pattern. In addition, it experienced different tectonic transformations since Late Mesozoic with extensional rift (Late Jurassic-Early Cretaceous and Paleocene-Early Eocene) and inversion compressing (Middle Eocene -Oligocene). The structure style of the Western Shandong is an extensional structural system in time of Late Meso-Cenozoic there are tectonic breccias, fault clay making up signs of faulting activity in the fault zone. Western Shandong experienced evolution of Late Jurassic-Early Cretaceous, Paleocene-Early Eocene and Middle Eocene- Oligocene, and each period shows different pattern of extensional structures.The tectonic stress field about study area in Meso-Cenozoic is simulated by the soft of ANSYS10.0. And then the evolution times of tectonic movement and the stress field characteristics in Shandong Province is obtained. In time of Late Jurassic-Early Cretaceous with NE-SW extensional orientation, a large number of EW faults in the Jiaolai Depression occurred, and NW faults in the West Shandong experienced tectonic inversion. In time of Paleocene - Early Eocene, the extensional orientation was SN, E-W faults in the Jiaolai Depression reached the strong extensional period and the Jiaolai Basin was formed. In this period, a part of NE faults in the West Shandong developed, and the movement of NW faults continued. In time of Middle Eocene-Oligocene, the transformation of Yi-Shu fault zone to Right-lateral strike-slip, the extensional orientation of the study area changed to NE-SW. So the Jiaolai Depression experienced the compression with the movement of NW faults continuing. In a word, the tectonic movement in both of the Yi-Shu fault zone decreased greatly, and started a relatively stable tectonic period.