地质通报2024，Vol.43Issue(5)：779-788,10.DOI:10.12097/gbc.2023.04.011
水化学和同位素揭示的广东儒洞地热咸水形成机制
The formation mechanism of geothermal salty water based on hydrochemistry and isotopes in Rudong geothermal field,Guangdong Province
摘要
Abstract
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.关键词
地热咸水/水化学/氢氧同位素/87Sr/86Sr/地热温度计/广东Key words
geothermal salty water/hydrochemistry/hydrogen and oxygen isotopes/87Sr/86Sr/geothermometer/Guangdong Province分类
天文与地球科学引用本文复制引用
邵誉炜,毛绪美,查希茜,李翠明,赵桐..水化学和同位素揭示的广东儒洞地热咸水形成机制[J].地质通报,2024,43(5):779-788,10.基金项目
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) （批准号:41440027）
