Numerical modeling analysis of the rotation deformation mechanism of the eastern margin of the Tibetan Plateau

The Tibetan uplift is controlled by the continuous collision of Indian plate and Euro-Asia plate as well as South China block and Ordos block. The materials on the southeast margin of the Tibetan Plateau escaped southward. The crustal motion of eastern Tibet indicates the clockwise rotation around the eastern Himalayan syntaxis. Making use of the contact element viscoelastic finite element (FE) method, the authors analyzed the mechanism of the rotation of the eastern margin of the Tibetan plateau. The FE model simulated the geological block structure which is bounded by large active faults. The simulated GPS accords well with the measured GPS, and the tectonic stress state coincides well with the property of active faults. The boundary conditions of FE modeling show that the material escape of southeastern Tibetan Plateau resulted from the lower crust dragging and the gravity influence, that during the southward escape the shear extension dragging along the sagging fault induced by oblique subduction of India plate under the Myanmar plate caused the rotation of eastern Tibetan Plateau around the eastern Himalayan syntaxis, and influenced the active structural system of southeastern Tibetan plateau.