花岗岩带状热储水化学与锶同位素地球化学特征

Water chemistry and strontium isotope geochemistry characteristic of granitic banded thermal reservoirs

江西省明月山地区位于宜春市西南部,地热资源丰富,揭示其水化学特征有利于地热资源保护和合理开发利用。收集并检测了39个水样本,采用水化学分析方法、相关分析法、水化学特征系数法分析了不同类型水样水化学组分含量特征及相关关系、水化学类型、钠氯系数、γMg/γCa系数和脱硫系数,同时根据锶同位素比值及浓度特征探明不同类型水的区别,阐明了研究区内水岩作用。结果表明:①不同类型的水样水化学组分之间存在一定的差异,TDS、pH、K^(+)、Na^(+)、HCO_(3)^(-)、SO_(4)^(2-)、F^(-)在地下冷水与地热水中均有不同程度的升高,地表水主要为Ca(HCO_(3))_(2)和NaHCO_(3)型水,地热水以NaHCO_(3)型水为主,泉水以Ca(HCO_(3))_(2)为主,地下冷水两个样品均为NaHCO_(3)型水。②γNa/γCl和γMg/γCa的比值表明研究区地下水成因主要受大陆溶滤水演化的影响,脱硫系数表明研究区内地下水含水层封闭性较差,控制研究区内地热水水化学演化的主要因素为岩石风化作用。

The Mingyue mountain in Jiangxi Province is located in the southwest of Yichun City,with rich geothermal resources.Revealing its hydrochemical characteristics is beneficial for the protection and rational development and utilization of geothermal resources.In this paper,39 water samples were collected and tested.The content characteristics and correlation of hydrochemical components,hydrochemical types,sodium chloride coefficient,γMg/γCa coefficient and desulfurization coefficient of different water samples were analyzed by hydrochemical method,correlation analysis method and hydrochemical characteristic coefficient method.Meanwhile,according to the characteristics of strontium isotope ratio and concentration,the differences between different types of water samples were clarified,and the water-rock interaction in the study area was understood.The results showed that:①There were certain differences among the hydrochemical components of different types of water samples,TDS,pH,K^(+),Na^(+),HCO_(3)^(-),SO_(4)^(2-) and F^(-) were all increased in different degrees in cold groundwater and geothermal water.The surface water was mainly Ca(HCO_(3))_(2)and NaHCO_(3)type,the geothermal water was mainly NaHCO_(3)type,and the spring water was mainly Ca(HCO_(3))_(2)type.The two samples of cold groundwater were all NaHCO_(3)type.②The ratio ofγNa/γCl andγMg/γCa indicated that the genesis of groundwater in the study area was mainly affected by the evolution of continental lixiviation water.The desulfurization coefficient indicated that the groundwater aquifer in the study area was poorly sealed,and the main factor controlling the hydrochemical evolution of geothermal water in the study area was rock weathering.