河北承德偏硅酸矿泉水成因模式:岩石风化与水岩作用证据  

Formation mechanism of metasilicate mineral water in Chengde, Hebei Province: Evidence from rock weathering and water-rock interaction

作　　者：孙厚云 孙晓明[1,3] 卫晓锋 陈自然[2] 刘卫 黄行凯 李霞[3] 殷志强[3] 刘文波[3] SUN Houyun;SUN Xiaoming;WEI Xiaofeng;CHEN Ziran;LIU Wei;HUANG Xingkai;LI Xia;YIN Zhiqiang;LIU Wenbo(School of Water Resources and Environment,China University of Geosciences(Beijing),Beijing 100083,China;Beijing Institute of Geology for Mineral Resources Co.,Ltd.,Beijing 100012,China;China Institute of Geo-Environment Monitoring,Beijing 100081,China;514 Brigade of North China Geological Exploration Bureau,Chengde 067000,Hebei,China)

机构地区：[1]中国地质大学(北京)水资源与环境学院,北京100083 [2]北京矿产地质研究院有限责任公司,北京100012 [3]中国地质环境监测院,北京100081 [4]华北地质勘查局五一四地质大队,河北承德067000

出　　处：《中国地质》2022年第4期1088-1113,共26页Geology in China

基　　金：中国地质调查局项目“承德市生态文明示范区综合地质调查”(DD20190822)和“地球关键带生态地质调查”(DD20190536)资助。

摘　　要：【研究目的】承德地处京津冀水源涵养功能区,矿泉水资源丰富,研究其赋存分布与形成机制对矿泉水可持续利用与水源涵养优化具有重要意义。【研究方法】采用岩石地球化学和水化学分析、化学风化指数、矿物表面微观形态分析,同位素示踪等方法系统梳理了研究区地下水偏硅酸空间分异的影响因素,从岩石风化与水化学耦合角度探讨了偏硅酸矿泉水的成藏机制。【研究结果】结果表明:研究区常温水体偏硅酸含量达30 mg/L以上样品占比达5.16%,地热水偏硅酸平均含量达61.76 mg/L。偏硅酸矿泉水成藏受岩石风化和地质构造控制,风化酸性介质影响,水化学形成作用制约。风化敏感程度愈高,易风化矿物含量愈高的含水介质赋存地下水偏硅酸含量愈高。研究区硅酸盐岩总体处于初等化学风化——长石类矿物和辉石等镁铁质矿物风化形成高岭石、蒙脱石和伊利石阶段。构造深部幔源CO_(2)、工矿活动和人类生产生活输入的外源硫酸和硝酸共同参与岩石风化脱硅过程,偏硅酸矿泉水、地热水温泉出露处多为构造复合部位或主干断裂与次级断裂的交汇部位。【结论】承德市偏硅酸矿泉水成因模式可概化为构造断裂深循环淋溶型、风化裂隙浅循环淋溶型和层间孔隙裂隙-补给富集埋藏型3类。植被覆盖较好的玄武岩、火山碎屑岩、陆源碎屑岩流域山前宽缓沟谷与导水断裂交汇带,侵入岩导水导热断裂带、侵入岩与围岩接触带,花岗岩、片麻岩和陆源碎屑岩与碳酸盐岩接触带为偏硅酸矿泉水开采潜力区。[Objective]The orientation of Chengde City's primary function of ecological environment in Beijing-Tianjin-Hebei Urban Agglomeration is a water conservation area due to its abundant water resource endowment.It is of great significance to clarify the occurrence,spatial variation,and formation mechanism of metasilicate mineral water for the sustainable utilization of water resources and the optimization of water conservation.[Methods]Multivariate statistical analysis,rock-wreathing lithogeochemical,hydrogeochemical,and multiple isotopic(δD,δ^(18)O andδ^(13)C)approaches were systematically conducted to identify the influencing factors of the enrichment and spatial variation of metasilicic acid in groundwater in the study area under a water-rock interaction perspective of the Earth’s Critical Zone.[Results]The results showed that the normal temperature water samples with soluble SiO_(2) concentrations higher than 30 mg/L accounted for 5.16%,while the average concentration of soluble SiO_(2) of geothermal water reaches 61.76 mg/L.The enrichment of soluble SiO_(2) in groundwater was controlled by the rock-weathering desiliconization process and water yield property and transmissivity of geological structures,simultaneously restricted by the recharge of weathering medium acidic substances and hydrochemical formation process in aqueous porous media.The higher the weathering sensitivity of water-bearing media,or the higher the content of easily weathered minerals in exposed strata,the higher the concentration of soluble SiO_(2) in aquifers tend to obtain.The hypergene silicate rock of the study area was generally in the primary chemical weathering stage that kaolinite,montmorillonite,and illite were formed during the dissolution of feldspar minerals,pyroxene,and other mafic minerals.The mantle-derived CO_(2),exogenous sulfuric acid,nitric acid generated by mining,artificial and agricultural activities were demonstrated to be jointly involved in the rock weathering process.The metasilicate mineral water and geothermal

关 键 词：偏硅酸矿泉水 水文地球化学 岩石风化 水岩相互作用 水文地质调查工程 承德 河北省 

分 类 号：P641.5[天文地球—地质矿产勘探]