摘要
The Xiangfan-Guangji fault zone experienced two phases of deformation events since collision and deep subduction of the Yangtze and north China plates in Middle Triassic. The earlier deformation event took place during the orogenic exhumation of the latest Middle Triassic to earliest Late Triassic, and resulted in formation of ductile shear zone along the southern border of the orogenic belt. The NW-SE shear zone dips SW steeply, shows NW-SE mineral lineation and thrusting dextral shear sense. It represents a boundary strike-slip shear zone developed during oblique exhumation of the orogenic belt. The exhumation caused previous E-W folds in the northern foreland fold and thrust belt being changed into NW-SE trends. The later deformation event in the fault zone happened in Late Jurassic, and resulted in brittle thrusts and NE-ward thrusting of the foreland fold and thrust belt over the orogenic belt. A series of thrusts in the foreland fold and thrust belt were also associated with this deformation event. The later thrusting in the Xiangfan-Guangji fault zone is coeval with sinistral faulting of the Tan-Lu fault zone, and represents initiation of the circum-Pacific tectonic regime.