Effective Elastic Thickness of Continental Lithosphere in Western China

Western China has the most spectacular tectonic features on the continental Earth. It possesses the world highest plateau (Tibet), the world largest intra-continental strike-slip fault (Altyn Tagh) and the world highest intra-continental mountain belt (Tienshan Mountains). As the convergence belt between India plate and Europe plate, this region is a good place for the study of lithosphere dynamics. In this paper, the authors use gravity data and topography data to demonstrate the correlation of these conspicuous upper crustal structures with the deformation of the upper mantle lithosphere in China. we compute the effective elastic thickness of the elastic plate using three-dimensional finite difference in space domain according to the rheology of the continental lithosphere. This model considers the variation of the mechanical strength in vertical and horizontal orientation. The modeling results show that the effective elastic thickness of the lithosphere in China varies significantly from elastic thickness of 6-10 km in highly deformed mountain belts to over 60 km in stable platform areas. The effective elastic thickness of Tibet, Tarim, southern Tienshan and northern Tienshan are separately 30, 40-50, 10-15 and 30 km. While the effective elastic thickness in the western portion of the Altyn Tagh fault (west of 90°E) is less than that in the eastern portion.