宁夏清水河上游浅层地下水咸化作用研究
Study on the Salinization Mechanism of Shallow Groundwater along the Upstream Qingshui River in Ningxia

摘要： 认识干旱区地下咸水的形成机制对水资源管理和规划具有重要意义。在宁夏清水河平原上游采集52组浅层地下水化学样品和8组易溶盐样品，分析了地下水咸化的水文地球化学作用，利用元素质量平衡法计算了各作用对地下水盐分的贡献比率。结果表明：沿径流方向，地下水咸化程度呈增加趋势。咸化作用主要为岩石风化，并具空间分异，在补给区以碳酸盐风化为主，在强径流区硫酸盐风化占优，在弱径流区硫酸盐和岩盐风化共同提供了68%～93%的盐量。随着地下水TDS增加，蒸发岩贡献比率上升，碳酸盐和硅酸盐贡献比率下降。蒸发岩风化是导致浅层地下水咸化的首要因素。
Abstract: Research on salinization mechanism of groundwater in arid areas is of great significance for water resources management. Fiftytwo groundwater samples and eight rock samples were taken from the upstream Qingshui river plain in Ningxia. Hydrogeochemical processes controlling groundwater salinization were studied and their contribution ratios to salinity were calculated using element mass balance method. The results show that the salinization extent increased along groundwater flow path. The salinization processes mainly depended on rock weathering and had a spatial variation. Carbonate weathering played a dominant role in recharge area and sulfate weathering in strong runoff area. In slow runoff area, 68-93 percents of total salt were supplied by sulfate and halite weathering. The contribution ratios of evaporite increased with groundwater TDS, while carbonate and silicate had an opposite trend, which indicated that evaporite weathering controlled groundwater salinization