Geothermal‐type Lithium Resources in Southern Xizang, China

Abstract

AbstractHigh‐temperature geothermal water has abundant lithium (Li) resources, and research on the development and utilization of geothermal‐type lithium resources around the world are increasing. The Qinghai–Tibetan Plateau contains huge geothermal resources; especially, Li‐rich geothermal resources in southern Xizang, southwestern China, are widely developed. The Li‐rich geothermal spots in Xizang are mainly distributed on both sides and to the south of the Yarlung Zangbo suture zone. Such resources are often found in the intensely active high‐temperature Li‐rich geothermal fields and, compared with other Li‐rich geothermal fields around the world, the Li‐rich geothermal fluid in the Xizang Plateau, southern Xizang is characterized by good quality: the highest reported Li concentration is up to 239 mg/L; the Mg/Li ratio is extremely low and ranges from 0.03 to 1.48 for most of the Li‐rich geothermal fluid; the Li/TDS value is relatively high and ranges from 0.25–1.14% compared to Zhabuye Li‐rich salt lake (0.19%) and Salar de Uyuni (Bolivia) (0.08–0.31%). Continuous discharge has been stable for at least several decades, and some of them reach industrial grades of salt lake brine (32.74 mg/L). In addition, elements such as boron (B), caesium (Cs), and rubidium (Rb) are rich and can be comprehensively utilized. Based on still‐incomplete statistics, there are at least 16 large‐scale Li‐rich hot springs with lithium concentration of 20 mg/L or more. The total discharge of lithium metal is about 4300 tons per year, equivalent to 25,686 tons of lithium carbonate. Drilling data has shown that the depth is promising and there is a lack of volcanism (non‐volcanic geothermal system). With a background of the partial‐melting lower crust caused by the collision of the Indo‐Asia continent and based on a comprehensive analysis of the tectonic background of southern Xizang and previous geological, geophysical, and geothermal research, deep molten magma seems to provide a stable heat source for the high‐temperature Li‐rich geothermal field. The Li‐rich parent geothermal fluid rushes to the surface to form hot springs along the extensively developed tectonic fault zones in southern Xizang; some of the Li‐rich fluid flows in to form Li‐rich salt lakes. However, most of the Li‐rich geothermal fluid is remitted to seasonal rivers and has not been effectively exploited, resulting in great waste. With the continuous advance of lithium extraction technologies in Li‐rich geothermal fluid, the lithium resource in geothermal water is promising as a new geothermal type of mineral deposit, which can be effectively exploited. This is the first study to undertake a longitudinal analysis on the characteristics, distribution and scale, origin and utilization prospects of Li‐rich geothermal resources in southern Xizang, research that will contribute to a deeper understanding of Li‐rich geothermal resources in the area and attract attention to these resources in China.