Dynamic simulation of lithospheric evolution from the modern China mainland and its surrounding areas
中国大陆及周边地区现代岩石圈演化动力学模拟

Recent 0.2Ma evolution of lithosphere in the China mainland is modeled using finite element analysis.The effects of collision between Eurasia and Indian Plates on the strain and stress field in the China mainland are studied. Combining with GPS surveys, seismological data and geological analysis, we try to probe into the basic patterns of strain and stress field in this area on the time scales of several million years, 0.1 million years and tens of years. The results show that the India-Eurasia collision and the stress environment caused by the continuous northward extrusion of the Indian Plate play a key role in controlling the tectonic movement and lithospheric evolution of the Tibetan Plateau and its surrounding areas, while in the regions far away from the Tibetan Plateau, it becomes weak. Faults and gravity potential produce significant effects on the eastern and the western parts of the Tibetan Plateau and Tarim Basin. In the Tibetan Plateau, these effects increase the rate of lateral deformation; in the southern parts of Tibet, they create an extensional stress field, while in the Tarim Basin, they make it dextrorotate. The calculated horizontal velocities are well consistent with GPS surveys. However, in vertical dimension, quite large differences are observed in some areas, which means modern uplifting of the Qinghai_Tibetan Plateau depends not only on the Indian-Eurasian collision, but also on other kinds of mechanisms, such as mantle convections, isostatic effects and all kinds of erosions. The calculated stress field is consistent with the observed data. The Indo-Asian collision has mainly controlled the principle tensional stress field in the western part of China, but other kinds of mechanisms, such as gravity and mantle convections, have a very important impact on the eastern Tibetan Plateau. The Indo-Asian collision controls the seismicity of the western part of China, but except North China, where the seismicity is very active while the calculated stress level is very low. This puzzle probably means that other forces have made the North China block reactive.