Geothermal data analysis at the high-temperature hydrothermal area in Western Sichuan

作     者：ZHANG Jian LI WuYang TANG XianChun TIAN Jiao WANG YingChun GUO Qi PANG ZhongHe 

作者机构：Key Laboratory of Computational Geodynamics Chinese Academy of Sciences University of Chinese Academy of Sciences Institute of Geology and Geophysics Chinese Academy of Sciences 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2017年第60卷第8期

页      面：1507-1521页

核心收录：

学科分类：070904[理学-构造地质学] 070801[理学-固体地球物理学] 0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 41574074, 41174085, 41430319) the Innovation Team Project of Chinese Academy of Sciences (Grant No. KZZD-EW-TZ-19) the Strategic Pilot Technology of Chinese Academy of Sciences (Grant No. XDA1103010102) 

主　　题：Western Sichuan Plateau Fracture zone and thermally conductive structure Deep thermal structure Heat flow estimation 

摘      要：The western Sichuan hydrothermal area is located at the northeastern margin of the eastern syntaxis of the Qinghai-Tibet Plateau, which is also the eastern end of the Mediterranean-Himalayan geothermal activity zone. There are 248 warm or hot springs in this area, and 11 have temperatures beyond the local boiling temperature. Most of these hot springs are distributed along the Jinshajiang, Dege-Xiangcheng, Ganzi-Litang, and Xianshuihe faults, forming a NW-SE hydrothermal belt. A geothermal analysis of this high-temperature hydrothermal area is an important basis for understanding the deep geodynamic process of the eastern syntaxis of the Qinghai-Tibet Plateau. In addition, this study offers an a priori view to utilize geothermal resources, which is important in both scientific research and application. We use gravity, magnetic, seismic, and helium isotope data to analyze the crust-mantle heat flow ratio and deep geothermal structure. The results show that the background terrestrial heat flow descends from southwest to northeast. The crustal heat ratio is not more than 60%. The high temperature hydrothermal active is related to crustal dynamics processes. Along the Batang-Litang-Kangding line, the Moho depth increases eastward, which is consistent with the changing Qc/Qm(crustal/mantle heat flow) ratio trend. The geoid in the hydrothermal zone is 4–6 km higher than the surroundings, forming a local platform. The NW-SE striking local tensile stress zone and uplift structure in the upper and middle crust corresponds with the surface hydrothermal active zone. There is an average Curie Point Depth(CPD) of 19.5–22.5 km in Batang, Litang, and Kangding. The local shear-wave(S-wave) velocity is relatively low in the middle and lower crust. The S-wave shows a low velocity trap(Vs3.2 km s.1) at 15–30 km, which is considered a high-temperature partial melting magma, the crustal source of the hydrothermal active zone. We conclude that the hydrothermal system in this area can