Numerical simulation of the geodynamical condition about the channel flow model in Tibetan plateau

Being a possible geodynamical mechanism, "crustal flow" comes up with corresponding models in resolving and predicting the tectonics, metamorphism and exhumation of high terranes in the Himalayan-Tibetan orogenic system. This paper adopts 2-D viscoelastic models to discuss the geodynamical boundary condition for the deep material flow in Tibetan plateau, based on the average geophysical model of the crust and upper mantle. The result shows: (1) As non-smoothly contact mode, the solid materials of the lower crust and upper-mantle lid beneath the Tibetan plateau do not have the boundary condition to move mutually, which means that "channel flow" model cannot independently occur freely nearby Moho interface. The simultaneous transfer of the deep medium of "lower crust and upper-mantle lid" can possibly happen by the enough force source, which takes the low-velocity layers as upper detachment interface at depths 20 similar to 30 km, and the top of asthenosphere as lower detachment interface at depths 100 similar to 110 km. (2) "Channel flow" is hard to move without the former sufficient and necessary conditions. So, the deep materials flow in Tibetan plateau is not universal, and only happens in local and particular circumstance.