3D Rheological Structure of the Continental Lithosphere Beneath China and Adjacent Regions

AbstractRheological structure controls the intensity and styles of the lithospheric deformation. With the constraint of the upper mantle temperature derived from seismic velocity and the surface temperature from observation of meteorological stations, we have calculated the three‐dimensional thermal structure of the continental lithosphere beneath China and adjacent regions according to the observed thermal parameters. Based on the 3D thermal structure and strain rates derived from GPS observation, we have calculated the rheological structure of the continental lithosphere with the constraint of three deformation mechanisms: frictional strength, fracture strength, and creep strength. The results show that a weak ductile lower crust is widespread beneath China and adjacent regions. The weakest and thickest lower crust is found beneath the Tibetan Plateau. The rheological strength and effective viscosity of the lower crust are usually lower than that of the upper crust and the lithospheric mantle for two orders of magnitude. The lithospheric strength and effective viscosity of the Tibetan Plateau is lower than that of North China, South China and Indian plate. In general, the lateral variations of the lithospheric rheology are consistent with the spatial patterns of late Cenozoic crustal deformation and gravity lineament.