水化学和同位素揭示的广东儒洞地热咸水形成机制OA北大核心CSTPCD
The formation mechanism of geothermal salty water based on hydrochemistry and isotopes in Rudong geothermal field,Guangdong Province
地热咸水的形成机制是开发地热资源的重要参考,地热咸水中的化学组分可以揭示经历的水化学作用,同位素的示踪可以指示地下水的来源和水化学过程.因此,选用水化学和同位素来揭示广东儒洞地热咸水的来源和形成机制.研究表明,广东儒洞地热田发育高盐度地热水(TDS>8000 mg/L),Cl-和Ca2+的含量分别高达 5059.76 mg/L和 1991.42 mg/L,为Cl-Ca·Na型水.K-Mg温标和玉髓温标估算热储温度 88.13~121.42℃,循环深度 1963~2790 m.水文地质条件和氢氧同位素结果证实,地热水来自于东部丘陵地区的大气降水补给,补给高程为 260~315 m.通过离子比例系数和87Sr/86Sr分析,儒洞地热田地下水运移的环境较封闭,高温下发生了较充分的花岗岩矿物的溶解,同时围岩中蒸发成因盐岩的溶解提供了主要水化学组分,海水入侵的可能性较小,地热咸水和围岩存在一定的阳离子交换作用.因此,围岩中的蒸发成因盐岩的溶解和花岗岩矿物的溶解是地热咸水化学成分形成的主因.
The formation mechanism of geothermal salty water is important scientific basis for the exploitation of geothermal resources.The chemical components in geothermal salty water can reveal the experienced hydrochemistry,and the isotopic tracing can indicate the source of groundwater and hydrochemical processes.Therefore,water chemistry and isotopes were chosen to reveal the source and formation mechanism of geothermal salt water in Rudong geothermal field,Guangdong.The hydrochemisty indicates that the Rudong geothermal field develops high salinity geothermal water(TDS>8000 mg/L)with Cl-and Ca2+contents as high as 5059.76 mg/L and 1991.42 mg/L,respectively,which is Cl-Ca·Na type water.The reservoir temperatures estimated with K-Mg geothermometer and chalcedony geothermometer are about 88.13~121.42℃,and the circulation depths are about 1963~2790 m.Hydrogeological conditions and hydrogen-oxygen isotope results confirm that the geothermal water comes from atmospheric precipitation recharge in the eastern hills with the recharge elevations of 260~315 m.Based on the ion ratio coefficient and 87Sr/86Sr,the environment for groundwater transport in the Rudong geothermal field is relatively closed,and the dissolution of granite minerals occurs more fully at high temperatures,while the dissolution of evaporative salt rock in the surrounding rocks provides the main water chemical components.The possibility of seawater intrusion is weak,and there is a certain cation exchange between the geothermal salty water and the surrounding rocks.Therefore,the dissolution of evaporative salt rock in the surrounding rocks and the dissolution of granite minerals are the main source of chemical composition for the geothermal salty water in Rudong geothermal field.
邵誉炜;毛绪美;查希茜;李翠明;赵桐
中国地质大学(武汉)环境学院,湖北武汉 430074
地球科学
地热咸水水化学氢氧同位素87Sr/86Sr地热温度计广东
geothermal salty waterhydrochemistryhydrogen and oxygen isotopes87Sr/86SrgeothermometerGuangdong Province
《地质通报》 2024 (005)
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国家自然科学基金项目《富CO2热泉水14C年龄校正及其指示的广东深部地热水更新能力研究》(批准号:41440027)
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