Tarim rotation mechanism and the differential deformation responses along the Tian Shan

Abstract

SUMMARY Rotation of rigid blocks within continental interiors far from the plate convergence boundary is an unusual process, the dynamics of which is not clear. The Tarim block, as a rigid Precambrian block in central Asia, is surrounded by the Tibetan–Pamir plateau to the south and Tian Shan mountains to the north. Numerous geophysical data suggested that the Tarim block experienced significant clockwise rotation in the Cenozoic. Meanwhile, contrasting deformation patterns and associated topographic responses were observed between the western–central and eastern Tian Shan. The relationship among the India–Asia collision, Tarim rotation, and Tian Shan responses are poorly constrained. Here, a series of large-scale, high-resolution 3-D numerical models were constructed. The model results reveal that the collision of the indenting Indian lithosphere with the southwestern rim of the Tarim block triggers clockwise rotation of the Tarim block. Further on, the Tarim rotation produces differential deformation responses along the strike of Tian Shan, that is convergence-induced higher compression and strong uplifting in central Tian Shan but divergence-induced less compression and moderate uplifting in eastern Tian Shan. Thus, the Tarim rotation serves as an indispensable linkage between the Tibetan plateau evolution and the far-field Tian Shan activation.