塔里木盆地南部上地幔各向异性研究

The southern margin of Tarim, the front edge of the collision between the Tarim block and the Qinghai-Tibet Plateau, is an important place for understanding the interaction between the Qinghai-Tibet Plateau and surrounding blocks. The shear wave splitting method can obtain the media anisotropy characteristics of the lithospheric and asthenospheric mantle, and study of the lithosphere deformation and mantle flow. In this paper, we use the shear wave splitting method to analyze the SKS and SKKS phases recorded by eight broadband portable seismic stations jointly deployed by the Institute of Geology and Geophysics of the Chinese Academy of Sciences, Peking University and Southern University of Science and Technology in the southern Tarim Basin, and obtains anisotropy parameters in the upper mantle. The results show that the fast-wave polarization direction in the study area is generally consistent and nearly east-west, but there is a variation from the edge of the basin to the middle of the basin, and the delay time is about 0. 3 to 1. 5 s, and the difference is relatively large. Based on previous studies of shear wave splitting on the northern margin of the Qinghai-Tibet Plateau and around the Altyn Fault, most areas in the study area have the same direction of mantle flow and absolute plate movement. The SEE flow of the marginal asthenosphere disturbs the mantle flow under the Tarim block, and as it enters the Tarim block, the interference becomes weaker and weaker. At the same time, asthenosphere materials in the northern Qinghai-Tibet Plateau may affect the lithosphere of the Tarim Basin. As the mantle material continues to move northward, it gradually cools, and its influence on the inner lithosphere of the basin becomes weaker.