Thrust Tectonics in the Eastern Segment of the Intraplate Yanshan Orogenic Belt,Western Liaoning Province,North China

The tectonic framework, kinematics and the development of the thrust fault system of the eastern segment of the Mesozoic intraplate Yanshan orogenic belt in western Liaoning province are described in the paper. The tectonic settings and the significance of this fault system have been evaluated following the aforementioned de-scription. The thrust fault system consists of six master thrust faults. Both the northwestern and the southeast-ern faults of them extend east-north-east. The thrust faults between them take, however, the orientation of north-east-north. All these thrust faults tend to be connected together in the northeast and the southwest part respectively. In the northeastern part they tend to get together along the Lingyuan-Dongguanyingzi thrust fault. In the southwestern area they seem to be getting together along Yaolugou-Jinxi fault zone and its coun-terpart , Miyun-Xifengkou fault zone to the west. Structurally all those thrust faults form a tectonic frame-work which looks like a large-scale duplex. Both the geological interrelations and the dating results define a de-velopment sequence of the thrust fault system in this area. The thrusting commenced before Middle Jurassic and reached its deformation peak at the end of Jurassic. The tectonic framework of thrust faults in the area formed as a result of the extensive contraction during this time interval. Top-to-the-southeast movement dominates the thrusting of this tectonic system, which differ profoundly from those thrust faults in the middle and western parts of the intraplate Yanshan orogenic belt in propagation vergence. The spatial and temporal relations be-tween these thrust faults and the east-west trending dextral fault systems in the middle part suggests a unified tectonic model. This model implies that the top-to-northwest thrusting in middle and western part and the top-to-southeast thrusting in the eastern segment of Yanshan intraplate orogenic belt might formed as a result of a right lateral transform deformation along the latitude fault zones.