ABSTRACT
The Kouzhen-Guanshan Fault is the boundary structure between the Weihe Graben and the Ordos Block. In this paper, seven directional samples were collected from the bedrock section at Kouzhen Town in the western section of the fault. The microstructural characteristics of thin sections were observed under a microscope in an attempt to reveal the structure and evolution of The Kouzhen-Guanshan Fault. Microstructural analysis shows that the fault experienced at least two tectonic events: Caledonian compressive tectonic movement and Himalayan tensile tectonic movement. Among them, the tensile motion reflects that the fault has a sinistral movement component. This is consistent with the tectonic evolution of the Weihe Graben and the extension background of sinistral movement formed by the extrusion of the Qinghai-Tibet Plateau since Cenozoic. The comprehensive analysis shows that the microstructure characteristics of the Kouzhen-Guanshan Fault are highly coupled with the regional tectonic background, which can provide a scientific basis for understanding the formation, evolution, and kinematic characteristics of the fault.
