The research progress and problems of the crustal shortening effect of the main terranes in Qinghai-Tibet Plateau, China.

In this paper, based on the systematic collection, analysis and research of the existing data achieved in Himalayas, Lhasa and Qiangtang terranes, we conducted the balanced cross-section study. In the north Qiangtang, the line-balanced cross-section study shows that the Jurassic strata shortened by 25.18%, and the result in south Qiangtang is 33.57%. The balanced cross-section in Lhasa terrane is divided into two sections by central volcanic rocks. The study shows that the Late Cretaceous strata of the south section is shortened by 20.68%, while 25.3% for the north section. The crustal shortening of Triassic Jiangxiong Group of Langjiexue terrane in the eastern part of the Tethyan Himalaya block is up to 75%, higher than previous studies of the Tethyan Himalaya, 56%-60%. After contrasting our research results and the existing data, we analyzed the shortening process and tectonic deformation of the three terranes, and draw the conclusion that the shortening process is not a uniform process in each terrane, and the intraterrane deformation is mainly absorbed by the boundary of the stable blocks, suture zones and large thrust systems. The Cenozoic internal deformation in Qiangtang and Lhasa terranes is not serious.