海陆过渡界面浅层地下水可溶性SiO_2的变化特征——以雷州半岛和海南岛滨海地区为例  

Variation characteristics of dissolved SiO_2 in sea-land transition interface of shallow groundwater:Taking Leizhou Peninsula and Hainan Island coastline as examples

作　　者：黄向青[1] 何海军[1] 甘华阳[1] 路剑飞[1] 潘毅[1] 

机构地区：[1]广州海洋地质调查局国土资源部海底矿产资源重点实验室

出　　处：《水资源与水工程学报》2017年第2期62-67,共6页Journal of Water Resources and Water Engineering

基　　金：中国地质调查局"我国重点海岸带滨海环境地质调查与评价"项目(1212010914020)

摘　　要：硅为重要的地球化学元素,滨海地区作为地下水海陆过渡带,对地下水重要化学成分SiO_2的研究有助于进一步掌握海陆界面的水岩过程。在华南典型火山成因的雷州半岛和海南岛进行环岛浅层地下水连续取样和化学测试,分析模拟了可溶性SiO_2的变化、组成以及溶解平衡。结果表明:该地区地下水多为Na—Cl型,偏碱性,处于风化溶滤、蒸发浓缩状态或两者之间的过渡类型;地下水中可溶性SiO_2含量为2.80~106.0 mg/L,各测井变化较大,与周边环境条件有关,源自矿物溶解、海水入侵及其路径上的水岩作用;单个测井同一时段水样可溶性SiO_2含量呈波动变化,不同时段也变化明显;可溶性SiO_2以单分子正硅酸H4Si O4占据绝对优势,硅酸盐各类矿物呈现溶解、饱和、平衡的状态共存并且自身状态相互转化。总体来看,研究区地下水的饱和矿物种类比例偏高,因此,滨海地下水作为海陆过渡界面的高矿化度的开放体系,盐效应有促进不同矿物溶解或者饱和的作用。概而言之,上述可溶性SiO_2的水—岩过程受到多种因素影响,需要进一步加强研究。Due to the importance of silicon as a geochemical element,in coastal zone which is the transition zone of groundwater in coastal area,the study of the important chemical composition of groundwater SiO2 helps to further grasp the lithosphere rock process of sea-land surface. The continuous sampling and chemical tested of shallow groundwater were conducted in the typical volcanic caused region of south china,i. e.,along shoreline of Leizhou Peinsula and Hainan island. The change,composition and dissolving balance of dissolved SiO2 in shallow underground water were analyzed. The results revealed that,the types of underground water was primarily Na-Cl type,alkaline,either weathered and leached,evaporation concentration or transitional type between the two. Ranging from 2. 8 to 106. 0 mg/L with significant spatial and time variation for different test wells,the concentration of dissolved SiO2 was related to nearby environment and derived from mineral dissolution,seawater intrusion and water-rock activity effect. The concentration series of dissolved SiO2 varied even for the single test well at the same period,also changed significantly in the different periods. H4 Si O4was the absolutely dominant among three chemical species of dissolved SiO2.Different silicate minerals had coexistence of dissolution,saturation and r balance states and mutualy transformed between different states of themselves. Overall,the proportion of saturated mineral species in groundwater of the study area was high. Therefore,coastal groundwater as the sea-land transition interface on the open system of high salinity,salt had a promoting effect on dissolve or saturation of different minerals. In general,the water-rock process of soluble SiO2 was affected by many factors,needed further strengthen the research.

关 键 词：滨海地区 浅层地下水 海水入侵 可溶性二氧化硅 SiO2变化特征 

分 类 号：P342.1[天文地球—水文科学]