Numerical Analysis and Simulation Experiment of Lithospheric Thermal Structures in the South China Sea and the Western Pacific

• Published in: Journal of earth science (Wuhan, China) China), 2009-02, Vol.20 (1), p.85-94
• Main Author: 林舸 彭美丽 赵崇斌 张露 张德圣 刘士林
• Format: Article
• Language: English
• Subjects: Biogeosciences; Cenozoic; Earth and Environmental Science; Earth science; Earth Sciences; Fluctuations; Geochemistry; Geology; Geotechnical Engineering & Applied Earth Sciences; Heat transfer; Lithosphere; Marine; Marine geology; Numerical analysis; Ocean basins; Oceans; Simulation; Studies; Temperature; Upper mantle; 地壳浅部; 岩石圈厚度; 岩石圈热结构; 数值分析; 模拟实验; 海洋盆地; 西太平洋地区
• ISSN: 1674-487X; 1867-111X
• DOI: 10.1007/s12583-009-0009-0

The asthenosphere upwelled on a large scale in the western Pacific and South China Sea during the Cenozoic, which formed strong upward throughflow and caused the thermal structure to be changed obviously. The mathematical analysis has demonstrated that the upward throughflow velocity may have varied from 3×10^11 to 6×10^12 m/s. From the relationship between the lithospheric thickness and the conductive heat flux, the lithospheric heat flux in the western Pacific should be above 30 mW/m^2, which is consistent with the observed data. The huge low-speed zone within the upper mantle of the marginal sea in the western Pacific reflects that the upper mantle melts partially, flows regionally in the regional stress field, forms the upward heat flux at its bottom, and causes the change of the lithospheric thermal structure in the region. The numerical simulation result of the expansion and evolution in the South China Sea has demonstrated that in the early expansion, the upward throughflow velocity was relatively fast, and the effect that it had on the thickness of the lithosphere was relatively great,resulting in the mid-ocean basin expanding rapidly. After the formation of the ocean basin in the South China Sea, the upward throughflow velocity decreased, but the conductive heat flux was relatively high, which is close to the actual situation. Therefore, from the heat transfer point of view, this article discusses how the upward heat flux affects the lithospheric thermal structure in the western Pacific and South China Sea. The conclusions show that the upward heat throughflow at the bottom of the lithospheric mantle resulted in the tectonic deformation at the shallow crust. The intensive uplifts and rifts at the crust led to the continent cracks and the expansion in the South China Sea.