Hydrogeochemical Characteristics and Conceptual Model of the Geothermal Waters in the Xianshuihe Fault Zone, Southwestern China

Abstract

Abundant geothermal waters have been reported in the Yalabamei, Zhonggu, Erdaoqiao, and Yulingong geothermal areas of the Xianshuihe Fault Zone of western Sichuan, southwestern China. This study focused on the hydrogeochemical evolution, reservoir temperature, and recharge origin of geothermal waters using hydrochemical and deuterium-oxygen (D-O) isotopic studies. Shallow geothermal waters represented by geothermal springs and shallow drilled water wells are divided into two hydrochemical groups: (1) the Ca–Na–HCO3 type in the Erdaoqiao area, and (2) Na–HCO3 in other areas. Deep geothermal waters represented by deep drilled wells are characterized by the Na–Cl–HCO3 type. The major ionic compositions of geothermal water are primarily determined by the water–rock interaction with silicate and carbonate minerals. The reservoir temperatures estimated by multi-geothermometries have a range of 63–150 °C for shallow geothermal water and of 190–210 °C for deep geothermal water, respectively. The δ18O and δD compositions indicated geothermal waters are recharged by meteoric water from the elevation of 2923–5162 m. Based on the aforementioned analyses above, a conceptual model was constructed for the geothermal system in the Xianshuihe fault zone.

Study on the genetic mechanism of high-temperature geothermal system and its engineering impact in the Woka graben, Tibet

“…The temperature of geothermal springs, as natural outcrops of geothermal water systems, is often low because of the mixing of shallow groundwater or surface water and cannot actually represent the temperature of the geothermal reservoir Li et al, 2020;Chang et al, 2021). Therefore, quantitative geochemical geothermometers such as SiO 2 and cation geothermometers are usually used to calculate the reservoir temperature (Fournier, 1977;Truesdell and Fournier, 1977;Fournier, 1979).…”

Hydrogeochemical Characteristics and Formation of Low-Temperature Geothermal Waters in Mangbang-Longling Area of Western Yunnan, China

“…e thermodynamic process of the groundwater system can be clarified by mineral equilibrium calculation, which is helpful to reflect the process of water-rock interaction [14]. Mineral saturation indices (SI) of geothermal waters were calculated for evaluating mineral equilibrium based on discharge temperature and pH.…”

“…Due to the intensive tectono-magmatic evolution, the Himalaya geothermal belt in China is the famous geothermal area for massive geothermal energy, including southern Tibet, western Yunnan, and western Sichuan [13,14]. Among them, western Yunnan possesses numerous and widespread high-and low-temperature geothermal waters, representing an outstanding natural laboratory for investigating the genetic mechanism for the geothermal system [15].…”

Analysis of the Formation Mechanism of Medium and Low-Temperature Geothermal Water in Wuhan Based on Hydrochemical Characteristics

“…Geothermal resources integrate heat, water, and minerals in a highly utilizable, low-cost, and environmentally non-polluting way and can be used for power generation, heating, aquaculture, medical care, and spa bathing, with considerable economic and environmental benefits [3][4][5][6]. Hydrological and hydrogeochemical methods have been used in the early stages of geothermal field exploration, where hydrochemical and isotopic signatures often retain detailed chemical information about the processes of the formation and evolution of the geothermal system, helping to analyze the origins, formation conditions, and geochemical processes of geothermal fluids, as well as to evaluate the recharge sources, ages, classification of hydrochemical types, and analysis of water-rock equilibrium states, reservoir temperatures, and circulation depths [4,[7][8][9][10][11][12].…”