Two-stage activity of the Altyn Tagh Fault during the Cenozoic: Evidence from seismic attributes analysis

The structure units of northwestern margin of the Qaidam Basin had experienced complex structural deformation with the Tibetan Plateau continuous extrusion and Altyn Tagh strike-slip since Cenozoic, faults widely developed. It is difficult to clarify the spatial distribution of variety faults in the original three-dimensional (3D) seismic data. Seismic attributes analysis provides a method to get an accurate and unbiased view of fault features, especially in the geological interpretation process of complex region. This paper analyzes the faults of different depth in Xiaoliangshan anticline in the western part of the Qaidam Basin, located in south side of the Altyn Tagh Fault, found early EW-trending thrust faults in the deep, and with the Allyn Tagh Fault strike-slip in the late, forming NW-trending wedge-shaped thrust fault from deep to shallow, the activity of deep NW-trending fault triggered shallow detachment fault. Through comprehensive analysis, we can infer that the Allyn Tagh early uplift led to the formation of the EW-trending oblique thrust fault, and the Altyn Tagh Fault strike-slip movement. in the late formed the NW-trending thrust fault in the limbs of Xiaoliangshan anticline since Cenozoic. The activity of faults had two stages.