河北平原深层碱性淡水形成的水文地球化学模拟——以保定、沧州地区为例

以揭示河北平原深层碱性淡水化学形成机制为主要研究目的, 选择河北平原深层碱性淡水发育的保定、沧州地区为典型研究区, 应用水文地球综合分析方法和地下水地球化学模拟技术, 探讨了深层碱性淡水水化学性质、分布规律及形成的自然环境; 依据质量守恒原理建立深层地下水质量平衡反应模型, 研究了从山前至滨海整个水流路径上所发生的水文地球化学作用及水、岩间的质量交换, 从而揭示了深层地下水化学演化规律的内涵及深层碱性淡水水化学形成机制.主要结论是深碱性淡水是由山前补给区HCO₃-Ca·Mg水逐步演化而来, 从山前至中部平原, 在地下水环境由开放转为封闭的过程中, 方解石、白云石溶解和沉淀, 钠长石、石膏、岩盐和菱铁矿的溶解, Ca-Na阳离子交换是控制其形成和演化的主要水文地球化学作用. 

Hydrogeochemical Modeling for the Formation of Deep-Lying Alkaline Fresh Groundwater in Heibei Plain:a Case Study in Baoding and Cangzhou Districts

The deep-lying alkaline fresh groundwater in sedimentary system in Hebei plain is taken as a research object for the purpose of revealing its chemical formation mechanism. Taking Baoding and Cangzhou districts where the deep-lying alkaline fresh groundwater is widely distributed as a typical study area and using the hydrogeochemical synthetic analysis and modeling methods, the authors discussed the chemical property, distribution and formation environment of deep-lying alkaline fresh groundwater. According to the principle of mass conservation, they set up a mass balance reaction model and studied hydrogeochemical reactions and mass transfer between water and rock along the flow path from piedmont to coastal area so as to have brought to light the chemical evolution law of deep-lying groundwater and the formation mechanism of alkaline fresh water. Their main conclusion is that the deep-lying alkaline fresh groundwater is originated from the evolution of the HCO₃-Ca·Mg water in piedmont area, and that from the piedmont the middle plain, the dissolution and precipitation of calcite and dolomite, the dissolution of albite, gypsum, halite and siderite, and the cation exchange of Ca-Na during the processes of groundwater environment changing from "open" to "closed" are the dominant hydrogeochemical reactions leading to its formation and evolution.