Based on the teleseismic records of the dense broadband seismic array, the crustal anisotropy parameters of the west Ordos block and its adjacent regions were determined with P wave receiver functions. The results indicate that the dominant direction of the fast wave is N-S in the Alxa block, NEE-SWW in north Ordos block, N-S in south Ordos block, and E-W in the Yangtze block. The fast wave direction of crust anisotropy in north Ordos block is distinctly different from the south Ordos block and the Alxa block. The Dabashan thrust fold belt is a visible boundary of crust anisotropy, which implies that the crust anisotropy kept the information of ancient South China block and North China block. Comparing with the direction of the fast wave from the SKS splitting, we tentatively discussed the interaction mode between the crust and mantle. The crust and mantle are decoupled in south Ordos block and coupled in north Ordos block. Combining the results of previous geophysical studies, we presented a crust-mantle interaction model to explain the geophysical observations. The most prominent features of the model are the horizontal eastward expansion of the mantle material in the southern Ordos and the vertical upwelling of the mantle material in the northern Ordos. The different modes of movement of the mantle material led to the deep contrasting structures of north and south Ordos, including the crust anisotropy. The mantle upwelling also implies that north Ordos block might be currently experiencing craton destruction.

The deformation pattern and slip partitioning related to oblique underthrusting of the Tarim Basin in the eastern Tian Shan are not well understood because of the lack of interior deformation images. The Baoertu fault (BF) is an E-W-striking, ~350 km-long reactivated basement structure within the eastern Tian Shan. In this study, we quantify its late Quaternary activity based on detailed high-resolution remote sensing image interpretations and field investigations. Three field observation sites along an ~80 km-long fault segment indicate that the BF is characterized by sinistral thrust faulting. Based on surveying of the displaced geomorphic surfaces with an unmanned drone and dating of the late Quaternary sediments using radiocarbon and optically stimulated luminescence (OSL) methods, we estimate a late Quaternary left-lateral strike-slip rate of 1.87 ± 0.29 mm/yr and a N-S shortening rate of 0.26 ± 0.04 mm/yr for this fault. The lithospheric BF acts as a decoupling zone and accommodates the left-lateral shearing caused by the oblique underthrusting of the Tarim block. In the eastern Tian Shan, the oblique convergence is partitioned into thrust faulting across the entire range and sinistral slip faulting on the high-dip basement structure within the orogen. This active faulting pattern in the eastern Tian Shan of sinistral shearing in the center and thrust faulting at both sides can be viewed as giant positive flower structures.