柴北缘大柴旦地区地下热水成因:来自水化学及氢、氧、锶同位素的约束  

Gensis of geothermal water in the Da Qaidam area,northern margin of the Qaidam Basin:Constraints from hydrochemistry and isotopes of hydrogen-oxygen-strontium

作　　者：王兵 秦西伟 任二峰[1,2] 蒋子文 冯宁 李国荣 杨莎[1,2] 李玮 WANG Bing;QIN Xi-wei;REN Er-feng;JIANG Zi-wen;FENG Ning;LI Guo-rong;YANG Sha;LI Wei(Department of Geological Engineering,Qinghai University,Xining 810016,China;Key Laboratory of Cenozoic Resource&Environment in North Margin of the Tibetan Plateau,Xining 810016,China)

机构地区：[1]青海大学地质工程系,西宁810016 [2]青藏高原北缘新生代资源环境重点实验室,西宁810016

出　　处：《矿物岩石地球化学通报》2024年第1期167-177,共11页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：青海省科技计划项目(2021-ZJ-937Q)。

摘　　要：为探究柴达木盆地北缘的大柴旦地热田的水化学特征及成因模式,本文对研究区14组地下热水进行了水化学组分和同位素(δD,δ^(18)O,^(87)Sr/^(86)Sr,3 H)分析。结果表明,大柴旦地下热水出露温度为52~74℃,溶解性总固体浓度(TDS)为959.8~1451.3 mg/L。地下热水的水化学类型为Cl-Na型,区内地下热水的水化学成分主要来源于蒸发岩和硅酸盐矿物的溶解;氢、氧稳定同位素特征表明,大气降水及冰雪融水是地下热水主要补给来源,且部分温泉有岩浆水的补给,估算的补给高程为3591~4374 m。3 H测年结果表明,区内地下热水主要由1952年之前的古水补给、蒸发作用和水-岩反应增强导致。XSWQ-06和XSWQ-07样品有明显的氧漂移。基于SiO_(2)地热温标、多矿物平衡法和硅焓模型估算出的地下热水的热储温度为171~227℃,循环深度为4.7~6.9 km。该地区地热资源具有较大的开发利用潜力。In order to explore the hydrochemical characteristics and genetic model of the geothermal field in Da Qaidam,the northern margin of the Qaidam basin,14 groups of groundwater sample of this area were analyzed for hydrochemical components and isotopes(δD,δ^(18)O,^(87)Sr/^(86),3 H)in this study.The results show that the outlet temperature of underground hot water in Da Qaidam is 52~74°C,and the total dissolved solids(TDS)content is 959.8~1451.3 mg/L.The hydrochemical types of the groundwater are all the Cl-Na type,and according to the ion correlation and 87Sr/86Sr value,the main solutes of groundwater in the area originate from the dissolution of evaporites and silicate minerals.Stable isotopes of hydrogen and oxygen show that atmospheric precipitation is the main source of groundwater recharge and part of the groundwater is recharged by magma water,and the estimated recharge elevation is 3591~4374 m.XSWQ-06 and XSWQ-07 have significant oxygen drift,mainly due to evaporation and enhanced water-rock reaction.Based on the SiO_(2) geothermal temperature scale,the multi-mineral equilibrium method and the silicon enthalpy model,the thermal storage temperature of underground hot water in the area is estimated to be 171~227°C,and the circulation depth is estimated to be 4.7~6.9 km.The geothermal resources in this area have great potential for development and utilization.

关 键 词：水文地球化学 地下热水 热储温度 成因分析 大柴旦 

分 类 号：P595[天文地球—地球化学]