The Late Jurassic to Early Cretaceous Strike-Slip Faults in the Subei-South Yellow Sea Basin, Eastern China: Constraints From Seismic Data

摘要

Late Jurassic-Early Cretaceous strike-slip faults play an important role in basin formation and igneous activities in eastern China and the adjacent areas. Because of the lack of seismic data, their distribution and effect on the formation of basins and igneous activities in the Subei-South Yellow Sea Basin (SB-SYSB) are still poorly understood. In this study, based on systematic analyses of the acquired seismic data, the Late Jurassic-Early Cretaceous strike-slip faults in the SB-SYSB were identified and characterized. The strike-slip faults can be divided into two sets, a NE-NNE trending sinistral strike-slip fault system and a NW trending dextral fault system. They present in seismic sections as a flower structure or Y/V-shaped structure, respectively. In map view, they show horsetail splay faults, en echelon reverse faults, pull-apart structure, linear structure, or curvilinear structure. These faults resulted in different types of subbasins in the SB-SYSB, such as transpressional/transtensional subbasins and pull-apart subbasins. The close relationship between the strike-slip faults and the distribution of igneous rocks in the SB-SYSB suggest that the strike-slip faults probably acted as efficient pathways for magma intrusion during the Late Jurassic-Early Cretaceous. The sinistral displacement was characterized by thrusting-folding deformation structures, which show a tendency to decrease toward the Sulu orogenic belt, indicating that the Sulu orogenic belt has probably weakened the strike-slip movement in the basin. We infer that the sinistral strike-slip movement in the SB-SYSB was most likely controlled by the subduction of the paleo-Pacific plate and the Tan-Lu strike-slip faulting.