摘要
作为我国近些年地热勘探取得重要突破的地热田,西藏南部古堆地热田以其浅埋、高温、富锂、活动剧烈为典型特征而为人们广泛关注。然而关于其水化学特征和成因人们还知之甚少。古堆高温富锂地热田由五个地热显示区组成,分别是布雄朗古、杀噶朗噶、巴布的密、茶卡和日若地热显示区,其中布雄朗古、杀噶朗噶地热显示区地热活动最为强烈。古堆地热田沸泉和热泉的水化学类型主要为Na-Cl型,温泉和冷泉的水化学类型主要为Na-Cl-HCO_(3)、Na-HCO_(3)-Cl和Na-HCO_(3)型,地表水化学类型主要为Ca-Mg-SO_(4)-HCO_(3)和Na-Ca-Mg-SO_(4)-Cl-HCO_(3)型,这些不同的水化学类型可能反映其不同的成因和物质来源;K-Na地温计显示布雄朗古、杀噶朗噶、巴布的密、茶卡有相似的热储温度(最高可达240.56℃),且明显高于石英和K-Mg地温计计算结果;除了部分沸泉,多数地热水在Na-K-Mg三角图中的投点都远离完全平衡线,表明地热水在从热储上升至地表的过程中没有达到完全的化学再平衡,可能与冷水发生了混合;通过对地热流体特征元素的分析发现Cl、Na、K、SiO_(2)、B、As、Li、Rb、Cs和F是古堆地热流体的特征化学组分,Cl和其他特征化学组分之间良好的线性关系,表明了深部母地热流体的存在;通过对古堆地热流体焓-氯图解的分析表明古堆地热田深部可能存在两类不同的母地热流体,其Cl含量、焓值和对应的温度分别为567 mg/L、1562.5 J/g、335.5℃和697 mg/L、1250 J/g、282.5℃,并且古堆地热田的母地热流体可能是通过与围岩的热传导、沸腾或者与浅部地表冷水混合的冷却方式上升至地表形成不同温度、水化学类型和活动强度的热泉,本研究对深入认识我国西藏南部高温富锂地热系统的水化学特征和形成过程具有重要理论意义,同时对将来合理利用我国西藏南部清洁地热能和地热型锂资源具有重要的现实意义。
As the important breakthrough in geothermal exploration in Southern Tibet in recent years,the Gudui(Gobdu)high-temperature geothermal system has attracted widespread attention for its typical characteristics of shallow burial,high temperature,high lithium content and intense activity.The boiling springs and hot springs in the Gudui geothermal system are mainly Na-Cl type,the warm springs and cold springs are mainly Na-Cl-HCO_(3),Na-HCO_(3)-Cl and Na-HCO_(3)types,and the surface water mainly belong to Ca-Mg-SO_(4)-HCO_(3)and Na-Ca-Mg-SO_(4)-Cl-HCO_(3)types;these differences may reflect their different origins and material sources.The comprehensive analysis of Na-K,quartz,K-Mg geothermometer indicate that the reservoir temperature was up to 240.56℃.Except for four samples,the results of Na-K geothermometer is always higher than the quartz and K-Mg geothermometers.Most geothermal water samples collected from Gudui are far from the full equilibrium line in Na-K-Mg ternary diagram,suggesting that the complete chemical re-equilibrium has not been achieved as these geothermal waters flow upward from reservoirs towards spring vents and possibly mix with cooler waters.Geochemical characteristics analysis indicates that Cl,Na,K,SiO_(2),B,As,Li,Rb,Cs and F are the characteristic components of Gudui geothermal waters.The good linear relations between Cl and other characteristic constituents reflect the existence of a parent geothermal liquid(PGL)below Gudui.Comprehensive comparative analysis of the chloride-enthalpy diagram suggests that there may be two kinds parent geothermal liquid below Gudui that have Cl-concentration,enthalpy value and their corresponding temperature are 567 mg/L,1562.5 J/g,335.5℃and 697 mg/L,1250 J/g,282.5℃.The PGL ascends to the surface through different channels and may cool by conduction of heat to reservoir host rocks,by boiling,or by mixing with cooler groundwater.This study is of great significance to deeply understand the hydrochemical characteristics and formation process of high-temperature lithium-rich geothermal system in southern Tibet,and has important practical significance for the rational utilization of clean geothermal energy and geothermal-type lithium resources in southern Tibet in the future.
作者
王晨光
郑绵平
张雪飞
邢恩袁
叶传永
任建红
黎明明
何江涛
王丰翔
WANG Chenguang;ZHENG Mianping;ZHANG Xuefei;XING Enyuan;YE Chuanyong;REN Jianhong;LI Mingming;HE Jiangtao;WANG Fengxiang(Hebei Key Laboratory of Strategic Critical Mineral Resources,Hebei GEO University,Shijiazhuang,Hebei 050031,China;Institute of Resource and Environmental Engineering,Hebei GEO University,Shijiazhuang,Hebei 050031,China;MNR Key Laboratory of Saline Lake Resources and Environments,Institute of Mineral Resources,CAGS,Beijing 100037,China;School of Gemology and Materials Technology,Hebei GEO University,Shijiazhuang,Hebei 050031,China;Hebei Key Laboratory of Green Development of Rock and Mineral Materials,Hebei GEO University,Shijiazhuang,Hebei 050031,China;College of Geoscience and Surveying Engineering,China University of Mining and Technology,Beijing 100083,China;Institute of Geological Surveying,Hebei GEO University,Shijiazhuang,Hebei 050031,China)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2024年第2期558-578,共21页
Acta Geologica Sinica
基金
河北地质大学2023年国家预研项目(编号QN202302)
河北省岩石矿物材料开发重点实验室开放基金课题(编号RM202311)
国家自然科学基金重大研究计划项目(编号91962219)
中国地质科学院矿产资源研究所基本科研业务费项目(编号KK2012)
国家重点研发计划“战略性矿产资源开发利用”重点专项青年科学家项目(编号2021YFC2900100)
中国地质调查项目(编号DD20160054)联合资助的成果。
关键词
西藏南部
古堆高温地热田
水化学特征
成因
hydrochemistry characteristics
origins
high temperature Gudui geothermal field
southern Tibet
