Fault Tectonic Deformation And Evolution Of Litang Area

Litang regional fault structure located in the Sanjiang Tethyan orogenic belt, eastern margin of the Songpan- Garz orogenic belt southwest margin of the west side of the Yangtze plate, the continental crust is an important part of China Sanjiang Tethyan orogenic belt and Songpan- Garz orogenic belt.Litang area is located in the eastern edge of the Tibetan Plateau, where the fracture geometry structure, kinematics, kinetics for Sanjiang Tethyan orogenic belt, Songpan- Garz orogenic belt and the formation and evolution of the Yangtze plate is important. Litang area from plane geometry faults spread from the point of view can be divided into three main directions of fracture, namely north-south(N-S) fracture, north west- south east(NW-SE) to rupture and North East- South West( NE-SW) to break. In this paper, structural analysis method for faults geometry Litang region were observed in outcrop scale, kinematics and dynamics analysis and fault structure of the sub-regional and regional tectonic evolution of tectonic deformation fracture were discussed.This paper argues that since the Triassic, the number of faults deform Litang areas up to at least 6 times. In the early evening curtain Indo happened NW-SE direction collision squeezed under stress in this period, a NW trending cleavage, this article will squeeze the role of collisions in the study area as the first phase of construction deformation. The second phase of the maximum principal stress direction NE-SW, occurred late in the Indo-night curtain. Under the stress of this period, a fault plane tendency for NE, SW faults. Filled with a lot of late quartz veins within the fault zone. The third phase is tensile stress nature, the minimum principal stress direction NNE-SSW, this late in the Yanshan under stress, to the previously formed for NW faults are stretched, expanded(in this case the formation of quartz veins). Fourth stress direction EW, in the mid-Himalayan movement in this period of stress effect on the early times to the formation of faults, joints and faults within quartz veins varying degrees of dislocation, and the formation of the current sub-NE trending faults.Fifth stress direction NE- SW, in the early Pleistocene stress on this period, once again to the pre-formed faults, joints and veins within the fault of the different levels of error, and to strengthen the NW trending faults.Sixth stress direction unknown nature, formation time at the latest, about the early Pleistocene. Features many faults narrow(2-3cm), filled with a lot of fault gouge and crushed inside, and no quartz veins filling.It is much more regional stress direction of times now created a complex geological structure of Litang area faults.