华北断陷盆地中北部地热水地球化学特征及成因初探  

A Primary Study on Geochemical Characteristics and Genesis of Geothermal Water in the North-Central Part of the North China Downfaulted Basin

作　　者：路畅 李营[1] 陈志[1] 杨江 LU Chang, LI Ying, CHEN Zhi,YANG Jiang(CEA Key Laboratory of Earthquake Forecasting, Institute of Earthquake Science, China Earthquake Administration, Beijing 100036,China)

机构地区：[1]中国地震局地震预测重点实验室中国地震局地震预测研究所

出　　处：《矿物岩石地球化学通报》2018年第4期663-673,795,共11页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家自然科学基金项目(41573121);中国地震局地震预测研究所基本科研业务费专项(2018IEF0301);中国地震局地震监测预报司2018监测预报领域专项经费项目(YBZX-DQHX2018-03)

摘　　要：为探讨唐山-天津地区地热水的水化学类型、控制因素及其补给来源,2016年8月在华北断陷盆地中北部采取了21个温泉、地热井水样,进行离子特征,3He、4He、20Ne气体同位素及δD与δ18O稳定同位素分析。结果显示,华北断陷盆地中北部地热井温度为27. 5-92. 6℃,TDS（Total dissolved solids）为430. 3-2370. 8 mg/L,δD和δ18O分别为-74. 04‰--69. 27‰与-10. 32‰--8. 04‰; Na＋为主要阳离子,阴离子浓度变化较大,无明显空间分布规律。该区域水化学类型可以分为9类：Na-Cl·SO4、Na-Cl·SO4.HCO3、Na-Cl·HCO3、Na-HCO3、Na-SO4、Na-HCO3·SO4、Na-SO4·HCO3、Na-HCO3·Cl、Na-HCO3·SO4·Cl,水化学类型与含水层的岩性有关。He、Ne气体同位素组分表明,区域内地热水中气体具有幔源、壳源、大气来源的混合特征。H、O同位素组成指示地下水的补给来源为大气降水,δD平均值为-71. 62‰,基本等同于华北地区现今δD的平均值（约-70‰）,暗示其地下水年龄较小,补给时的气候条件与现今接近。S3、S6、S14、S17、S20有明显的氧漂移,主要原因是地热水温度较高,以及大陆效应与高程效应的影响。In order to discuss the chemical types,controlling factors,and supply sources of the waters in the TangshanTianjin area,the ion characteristics,3 He,4 He,20 Ne gas isotopes,and δD and δ18 O stable isotopes of 21 water samples,which were collected from 21 hot springs and geothermal wells in the north-central part of the North China Downfaulted Basin,have been analyzed in this paper. The results show that the waters of those geothermal wells have temperatures ranging from 27. 5 ℃ to 92. 6 ℃,contents of the total dissolved solids（ TDS） ranging from 430. 3 to 2370. 8 mg/L,and the δD and δ18 O values ranging from-74. 04‰ to-69. 27‰ and from-10. 32‰ to-9. 04‰,respectively. They contain main cation of the Na＋with the obviously irregular variation of anion concentrations in the spatial distribution. They can be classified into 9 types of the Na-Cl·SO4,Na-Cl·SO4·HCO3,Na-Cl·HCO3,Na-HCO3,Na-SO4,Na-HCO3·SO4,Na-SO4·HCO3,Na-HCO3·Cl,and Na-HCO3·SO4·Cl. Their chemical types are related to the lithologies of the aquifers.The He and Ne isotope compositions show that the gases of the geothermal waters in the region have the feature of mixing by mantle,crustal,and atmospheric sources. The hydrogen and oxygen isotope compositions indicate that the recharge source of groundwater is the meteoric water. The average δD of the groundwater is-71. 62 ‰,which is basically accordant with the average δD value of current meteoric water in the North China（ about-70 ‰）,suggesting that the groundwatercould be recently supplied with the climate condition at that time similar to the present. The obvious oxygen isotope drift phenomena of the S3,S6,S14,S17,and S20 samples could be mainly caused by the relatively high temperature of groundwater with minor influence by the continental effect and elevation effect.

关 键 词：地热水 氢氧同位素 氦同位素 离子浓度 

分 类 号：P592[天文地球—地球化学]