珊瑚岛礁地下水水化学特征及其形成机制

Hydrochemical Characteristics and Formation Mechanism of Groundwater in Coral Islands

我国热带海洋地区珊瑚岛礁星罗棋布,岛礁地下水对海洋环境和植物生态格局具有重要意义。为了揭示岛礁地下水的演化机制,基于西沙某珊瑚岛礁水文地质勘察和野外水样品采集分析,开展岛礁地下水主要水化学离子现场和室内测试,分析珊瑚岛礁地下水水化学总体分布特征和主要离子组分之间的关系,探讨了研究区地下水演化过程。研究表明岛礁地下水水化学类型为Cl-Na型和Cl-Na·Mg型,在岛礁地下水潜水面处更易发生活跃的碳酸盐矿物的溶解作用,在海水掺混、蒸发浓缩和含水层矿物溶解及沉淀作用等综合影响下造成岛礁地下水不同离子组分的增加或减少。

Coral islands are distributed in the tropical and marine areas of China,and its groundwater is of great significance to the marine environment and plant ecological pattern.In order to reveal the evolution mechanism of groundwater in coral islands,this paper analyzed the overall distribution characteristics of groundwater hydrochemistry and the relationship between main ion components based on the hydrogeological survey of a coral island in Xisha and the collection and analysis of wild water samples by carrying out the main hydrochemical ion field and indoor tests,and it explored the evolution of groundwater.The results indicate that the groundwater hydrochemical types of coral islands are Cl-Na and Cl-Na·Mg,and the dissolution of active carbonate minerals is more likely to occur in the groundwater surface of coral islands.Under the effects of seawater blending,evaporation concentration,aquifer mineral dissolution and sedimentation,the different ion components of groundwater in coral islands would be increased or decreased.