Recent Horizontal Movement And Deformation in The Northeast Margin of Qinghai–Xizang Block

Abstract

AbstractMaking use of GPS observational data in area of the northeast margin of Qinghai–Xizang block in the years 1993 and 1999, the distribution figures of velocity field and apparent strain field of crustal horizointal movement of this area are given, and the method of directly solving the parameters of block rotation and deformation from displacement observation is presented, so the characteristics of tectonic block motion and deformation in this area are studied preliminarily. The results show that: (1) This area shows a whole motion toward east‐southeast (whose velocity is about 9mm/a); (2) Gunsu–Qinghai block in the south of this area moves faster, but Alashan block in the north of this area moves slower, the difference of motion velocity between two blocks is near 6 mm/a, the sinistral strike slip movement of Qilian–Haiyuan fracture zone is remarkable; (3) There exists NNE‐NEE compressional movement from west to east; (4) Inside Alashan block and Gansu–Qinghai block, there are NWW tensional deformations, the whole tensional deformation of Alashan block is even more obvious, moverover, in the meeting region of blocks in the west side of Ordos block, compressional movement is relatively remarkable.