Structural Styles And Deformation Analysis Of Zhuyangguan-Xiaguan Fault Belt

Zhuyangguan-Xiaguan fault belt is the south dividing line of Erlangping back-arc basin and Qinling ancient island arc. In geometry it’s the north wing of northern Qinling positive flower structure. It is a series of decken stucture whcih trend towards S. It tends NWW-SEE, and trends in SSW. Rock bedding mainly trends in S, but inclination is unstable. Kinematic nature of Zhu-Xia fault belt is SSW-NNE nappe and subduction with sinistrality. Thus oblique nappe and subduction is Kinematic nature of Zhu-xia fault belt. It is caused by Erlangping back-arc basin subducted under the Qinling Group, and Qinling Group overthrust Erlangping. Regional tectonic stress field is characterized by σ1horizontal, strike-slip extrusion and One-way squeeze. It directs that Zhu-Xia fault belt formed in the power of regional squeeze with Strike-slip. The temperature and pressure of Zhu-Xia fault belt deformation environment is determined by micro data, Quartz C-axis fabric characteristics and mineral electron microprobe data. The fault belt’s center temperature is up to650℃, the highest pressure approaches0.65Gpa. The pressure and temperature decrease as the distance from the fault zone incressing. When Zhuyangguan-Xiaguan fault belt formed, it belonged to medium-high temperature and medium pressure environment, degree of metamorphism up to amphibolites facies.