Previous studies have shown that the uplift of Tibetan plateau started in response to the collision of Indian plate and Eurasian plate. During this process, the crust of Tibetan plateau has been greatly thickened whic...Previous studies have shown that the uplift of Tibetan plateau started in response to the collision of Indian plate and Eurasian plate. During this process, the crust of Tibetan plateau has been greatly thickened which leads to significant elevations. The elevation gradient is extremely large at the east boundary of Tibetan plateau where Longmenshan fault exists, dropping from 4500 to 500 m within a distance of 100 km, while it is more gentle at the south and north sides of Sichuan basin. Such a difference of elevation gradient has been explained with a crustal channel flow model. However, pre- vious crustal flow models consider the thickness of the lower crust as a constant which is highly simplified. Therefore, it is essential to build a more realistic crustal flow model, in which the thickness of the lower crust is variable and dependent on the inflow velocity of crustal materials. Here we build up both analytical and numerical models to study the mechanism and process of the uplift of Tibetan plateau at the eastern boundary. The results of the analytical model show that if the thickness of the lower crust can vary during the uplift process, the lower crustal viscosity of the Sichuan basin needs to be 1022 Pas to fit the observed elevation gradient. Such a viscosity is one-order magnitude larger than the previous results. Numerical model results further show that the state of stresses at the plateau boundary changes during uplift processes. Such a stress state change may cause the formation of different fault types in the Longmenshan fault area during its uplift history.展开更多
By considering that the coherent structure is the main cause of the Reynoldsstress, a new Reynolds stress expression was given. On this basis the velocity distribution in thetrapczoid-seclion open channel flow was wor...By considering that the coherent structure is the main cause of the Reynoldsstress, a new Reynolds stress expression was given. On this basis the velocity distribution in thetrapczoid-seclion open channel flow was worked out with the pseudo-spectral method. The results werecompared with experimental data and the influence of the ratio of length to width of thecross-section and the lateral inclination on the velocity distribution was analyzed. This model canbe used the large flux in rivers and open channes.展开更多
基金supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB18000000)Natural National Science Foundation of China (41374102 and 41422402)
文摘Previous studies have shown that the uplift of Tibetan plateau started in response to the collision of Indian plate and Eurasian plate. During this process, the crust of Tibetan plateau has been greatly thickened which leads to significant elevations. The elevation gradient is extremely large at the east boundary of Tibetan plateau where Longmenshan fault exists, dropping from 4500 to 500 m within a distance of 100 km, while it is more gentle at the south and north sides of Sichuan basin. Such a difference of elevation gradient has been explained with a crustal channel flow model. However, pre- vious crustal flow models consider the thickness of the lower crust as a constant which is highly simplified. Therefore, it is essential to build a more realistic crustal flow model, in which the thickness of the lower crust is variable and dependent on the inflow velocity of crustal materials. Here we build up both analytical and numerical models to study the mechanism and process of the uplift of Tibetan plateau at the eastern boundary. The results of the analytical model show that if the thickness of the lower crust can vary during the uplift process, the lower crustal viscosity of the Sichuan basin needs to be 1022 Pas to fit the observed elevation gradient. Such a viscosity is one-order magnitude larger than the previous results. Numerical model results further show that the state of stresses at the plateau boundary changes during uplift processes. Such a stress state change may cause the formation of different fault types in the Longmenshan fault area during its uplift history.
基金Project supported by Shanghai Key Subject Program
文摘By considering that the coherent structure is the main cause of the Reynoldsstress, a new Reynolds stress expression was given. On this basis the velocity distribution in thetrapczoid-seclion open channel flow was worked out with the pseudo-spectral method. The results werecompared with experimental data and the influence of the ratio of length to width of thecross-section and the lateral inclination on the velocity distribution was analyzed. This model canbe used the large flux in rivers and open channes.
