宁东煤田东北部高矿化度地下水分布特征及形成机制

宁夏宁东煤田东北部地下水矿化度较高，且具有分布不均和变化较大的特点。通过分析地下水矿化度的空间分布特征，结合区域地质构造、地下水补给径流条件，借助Piper三线图、Gibbs图、离子比例系数等手段，深入研究高矿化度地下水的形成机制。结果表明，宁东煤田东北部地下水矿化度为0.30~23.56 g/L，平均值为5.84 g/L，淡水、微咸水、咸水、盐水所占比例分别为3.16%、50.00%、33.68%、13.16%。水平方向上，基岩裂隙水矿化度由东向西逐渐降低，在鸳鸯湖矿区南部形成高矿化度异常带。此外，在研究区西部及南北部的零星地区出现矿化度较高区。矿化度整体较高与石膏、盐岩及黄铁矿溶解和地下水长期滞流有关，而矿化度由东向西逐渐降低则受鄂尔多斯台地逆冲推覆构造前缘坳陷影响。鸳鸯湖矿区南部位于鄂尔多斯台地南北冲断体系的过渡带，褶曲较完整，地下水环境相对封闭，形成高矿化度异常带。垂直方向上，从Ⅰ含水层至Ⅴ含水层深部含水层的矿化度比浅部高，主要与深部地下水环境封闭，更新较慢有关。该研究将为相似矿区地下水资源开发与利用提供理论依据。 

Distribution characteristics and formation mechanism of high salinity groundwater in northeast Ningdong Coalfield

High salinity groundwater is widely and unevenly distributed in northeast Ningdong Coalfield of Ningxia Hui Autonomous Region, and it varies greatly throughout the coalfield. This paper studies the distribution characteristics and formation mechanism of high salinity groundwater. Firstly, spatial distribution characteristics of high salinity groundwater was researched, and then, Piper trilinear graph, Gibbs graph and ion proportionality coefficient were used to investigate the formation mechanism of high salinity groundwater. The results show that groundwater salinity value varies from 0.30 g/L to 23.56 g/L, and the average value is 5.84 g/L. The proportions of fresh water, brackish water, salt water and salt water are 3.16%, 50.00%, 33.68%, 13.16% respectively. In the horizontal direction, the salinity of bedrock fissure water decreases gradually from east to west, and a high salinity anomaly zone is formed in the south of Yuanyang Lake mining area. In addition, high salinity anomaly zones occur in scattered areas of the west, north and south of the coalfield. The high salinity is related to the dissolution of gypsum, salt rock and pyrite and the long-term retention of groundwater. The mineralization gradually decreases from east to west due to the influence of the Ordos thrust nappe structure. However, Yuanyang Lake mining area is located in the transition zone of the south and north thrust systems of Ordos platform, with relatively complete folds and relatively closed groundwater environment. Thus, groundwater salinity is particularly higher than other area. In the vertical direction, from aquiferⅠ to aquiferⅤ, the groundwater salinity increase gradually. This is mainly related to the slow closure and regeneration of deep groundwater environment. The research will provide theoretical basis for the development and utilization of underground resources in Ningdong Coalfield and similar mining areas.