TECTONIC EVOLUTION OF THE ZHUANGHAI AREA, BOHAI BAY BASIN, EAST CHINA: THE APPLICATION OF BALANCED CROSS SECTIONS

The technique of balancing cross-sections play an important role in studying the tectonic history of sedimentary basins. It can restore structural growth history of sedimentary basin, and be widely used to analysis of petroleum structures. The principle of balancing cross-sections is that matter after strata de-formation keeps constant as that before deformation. In this paper, we selected two seismic profiles and compiled two structural growth sections in the Zhuanghai area of the Jiyang sag. The whole area sufferred from compression and uplifting during the Triassic-middle Jurassic phase because of intense extrusion stress related to the Indo-China movement. During the late Jurassic and early Cretaceous, intense exten-sion occurred in East China, and the whole area rifted, leading to the huge thickness of sedimentary se-quence. In the late Cretaceous, the area suffered from uplift and compression associated with the sinistral strike slip of the Tanlu fault. In the Palaeogene, a rifting basin developed in the area. Finally, it became stable and was placed in its present position by dextral strike-slip motion since Neogene.