Structural and sedimentary characteristics of the Liangjia-Wangchang strike-slip region, Yitong Basin, China

The Yitong Basin, a typical strike-slip basin, is part of the northern segment of the world-famous Tanlu strike-slip fault area in China. Research is needed to understand how the strike-slip tectonic environment affects the development of structures and depositional systems within the basin. The aim of this paper is to analyze how the right-lateral strike-slip movement of the northwestern boundary faults in this region controls extensional faulting, and to analyze differences in two main sedimentary sequences (termed SYSQ1 and SYSQ2) that result from strike-slip movement. The study is based on geological and geophysical data. The following conclusions are drawn: (1) The two periods of strike-slip movement of the boundary fault generated two episodes of extensional fault inside the basin. The extensional faults have a characteristically episodic activity related to the episodic strike-slip movement. The extensional faults have small fault throw, and their activity lags behind the strike-slip movement of the northwestern boundary faults. (2) The strike-slip movement of the boundary faults generated the extensional faults inside the basin and changed the locus of depocenters, with complimentary changes in the paleogeomorphology and in the distribution of depositional facies. It is this strike-slip movement that caused the differences in sedimentary and structural characteristics between sequences SYSQ1 and SYSQ2.

► The extensional faults were episodically active with the episodic strike-slip movement.
► These kinds of extensional faults have small fault throw.
► The activity of the extensional faults lags behind the strike-slip movement.
► The strike-slip movement changed the subsidence center and paleogeomorphology.
► The changed paleogeomorphology resulted in the change of depositional facies.