江西省安福地区地热水化学特征研究

为研究江西安福地区水文地球化学特征及控制因素, 本文采集了15组样品, 采用水化学、同位素分析等方法进行研究。结果表明: 研究区地热水以Na-HCO3型水为主, 地下水以HCO3-Na·Ca型为主, 地表水由西南向东北从HCO3-Na·Ca向HCO3-Ca型水演化。水化学组分演化过程主要受岩石风化作用控制, 地层封闭性较差, 水中的Na+、HCO– 3、Sr2+来源于硅酸岩风化溶解。由稳定同位素特征可知, 研究区地热水补给来源为大气降水。研究区热储温度为49.8~101.4 ℃, 地热水循环深度为1 502.6~1 513.6 m。热水在沿断裂带上升过程中与浅层冷水发生混合, 其混合比例为76.1%~87.5%。研究成果为安福地区水循环演化提供依据, 有利于地热资源的合理开采与保护。

Hydrochemical Characteristics of Geothermal Water in Anfu Area, Jangxi Province

To study the hydrogeochemical characteristics and control factors in the Anfu area of Jiangxi Province, we collected 15 groups of geothermal water samples and analyzed their isotopic and hydrochemical characteristics. The results revealed that the geothermal water in the study area was dominated by Na-HCO3-type water. The groundwater primarily comprised HCO3-Na·Ca-type water, and the surface water changed from HCO3-Na·Ca-type to HCO3-Ca-type from the southwest to the northeast in the region. Rock weathering primarily controlled the evolution process of hydrochemical components in the area, and the formation sealing was poor. Na+, HCO– 3, and Sr2+ in water originated from the weathering and dissolution of silicate. According to the analysis of stable isotope characteristics, the geothermal water in Anfu was of meteoric origin and had a slight 18O shift. The geothermal reservoir temperature in the study area ranged between 49.8–101.4 °C, and the geothermal water circulation depth was between 1502.6–1513.6 m. The geothermal water rising in the study area was mixed with shallow cold water, and the mixing ratio was calculated to be 76.1%~87.5%. These results provide a basis for understanding the evolution of the water cycle in the Ji’an area, which is conducive to the rational exploitation and protection of geothermal resources.