Geochemistry and Deep Geothermal Processes of Geothermal Springs Along The Xianshui River Fault Zone, Western Sichuan Plateau, China

The eastern margin of the Qinghai-Tibet Plateau, which located in the border of Songpan-Ganzi, Sichuan-Yunnan and South China blocks, is one of the most intense Cenozoic tectonic activity areas in Chinese mainland. The eastern margin of the Qinghai-Tibet Plateau has a high heat flow background related to Cenozoic plate interaction, high-temperature geothermal manifestations such as boiling springs, fumaroles, hydrothermal explosions and geysers are occurred on the surface, and are mainly distributed in the Xianshui River fault zone (XSF), Litang fault zone and Jinshajiang fault zone. In recent, with the support of "The National Key Research and Development Plan of Deep Resources Exploration and Mining (No.2017YFC0601205)", a systematic geological survey and evaluation of hot springs in western Sichuan was carried out. Therefore, combining with the research results of project, the hot springs developed along the XSF are systematically analyzed and regionalized. 58 hot springs were discovered in the XSF, of which 18 hot springs were high-temperature spring (>60℃), 28 hot springs were medium-temperature spring (40-60℃), and 12 hot springs were low-temperature spring (25-40℃). These hot springs were basically distributed in beads-shaped along the XSF, and most of them are concentrated distributed in group. Based on the zonality of the XSF and the characteristics of occurrence and distribution of hot springs, along the XSF can be divided into six hydrothermal areas: Luhuo, Daofu, Qingning-Bamei, Yalahe-Zhonggu, Kangding and Moxi hydrothermal area. The XSF is relatively active and has a certain degree of zonality, according to the seismic data and slip rate. Therefore, there is a good coupling relationship among the hydrothermal activity, earthquake, and fault near the XSF. It presents a coupling relationship between the the earthquake and hydrothermal activity. adjacent rocks and fault zones experienced intense compression and cutting, caused by the intense compression-slip of the XSF and resulting in the favorable environment of the deep circulation and reserve of the underground water and play a significant role in conduction and reservoir heat.