Mantle dynamics in the SE Tibetan Plateau revealed by teleseismic shear-wave splitting analysis

The tectonic evolution of the southeastern Tibetan Plateau is key to understanding mechanism growth whole Plateau. Its imprint on lithospheric and asthenospheric mantle rock fabrics expected have a strong signature seismic anisotropy. In this study, we measure splitting delays fast polarization directions (FPD) with minimum-transverse-energy intensity methods using core-refracted phases (e.g., SKS, SKKS, PKS) recorded by ChinArray experiment. potential complex anisotropic structures, i.e., frequency-dependent two-layer anisotropy, are investigated in particular. FPDs consistent different frequency bands, but delay times measured at low (8–20 s) often larger than those high (2–8 s). measurements can be better explained anisotropy model many stations. Splitting intensities also inverted constrain depth distribution upper mantle. Combined models, these results suggest patterns lithosphere asthenosphere. lithosphere, shows distinct blocks, while oriented along major boundaries. asthenosphere, continuous NW-SE spread from plateau Youjiang Orogen southwestern margin Yangtze craton, implying extrusion plateau. northern Indochina block, dominant E-W may indicate flow driven eastern subduction subsequent rollback Indian plate.