Estimation of the Cenozoic Strike-slip Displacement for Major Faults in the Liaodong Bay Depression and its Geological SignificanceEI北大核心CSCD

Estimation of the strike-slip displacement of faults in basins or covered regions has always been a hot and knotty issue. Based on the fine interpretation of 3D seismic data, we estimated the strike-slip displacements of the Cenozoic evolutionary stages of the main faults in the Liaodong Bay Depression, and analyzed their geological significance, using methods of physical modeling experiments and structural analysis. The results showed that two thirds of the strike-slip displacements of the major faults were converted into the horizontal displacement of those secondary extension faults in the Liaodong Bay Depression. It should be noted that the Liaodong Bay Depression isn't a pure strike-slip basin, and its Cenozoic evolution also influenced by extension, thus, extension amount produced by mantle upwelling should be detracted. Strike-slip movements were generated in the depositional stage of the first and second members of the Shahejie Formation, and the strike-slip displacements of major faults in different evolution stages vary considerably. In terms of the Cenozoic cumulative strike-slip displacement, the displacement of faults in the Liaozhong Sag is the largest, followed by those in the Liaodong Sag, and those in the Liaoxi Sag is the smallest. Among all of the faults, the Liaozhong1 fault had the largest strike-slip displacement. As to the displacement in different stages, the strike-slip displacement of all major faults showed the largest displacement in depositional stage of the Dongying Formation. The Neogene strike-slip displacement of faults is bigger than that of the depositional stage of the first and second members of the Shahejie Formation in the Liaoxi region, while it showed an opposite trend in the eastern Liaodong Bay Depression. The difference of relative strength between extensional and strike-slip stress controlled the difference of structural styles and basin structures in different evolution stages and structural locations in the Liaodong Bay Depression. The Cenozoic strong strike-slip effects in the Liaozhong and Liaodong Sag were presented by the obvious strike-slip characteristics on major faults and structural styles. In the Liaoxi Sag, the obvious “extension strike-slip” superimposed structural style was caused by the extension effects in the early Paleogene and strike-slip effects of the Dongying Formation and Neogene. © 2018, Science Press. All right reserved.