基于主导离子分类的呼和浩特盆地浅层地下水化学特征研究

Chemical characteristics of shallow groundwater in Hohhot basin

根据主要离子的毫克当量百分比是否超过50%,将呼和浩特盆地浅层地下水化学类型划分为主导离子型和无主导离子型,并在此基础上利用Piper三线图和各种离子比例系数对研究区浅层地下水的化学特征进行了研究。结果表明,浅层地下水阳离子水化学类型具有较强的水平分带性,阴离子中HCO3主导型水分布十分广泛。Ca主导型水全部为HCO3主导的低矿化度水,主要受溶滤作用控制;大黑河冲湖积平原中西部HCO3主导的Na主导型水的形成受阳离子交换作用和脱硫酸作用影响,该区域湖相沉积环境为其提供了有利的物质基础和环境条件;无主导阳离子型水和Mg主导型水的水化学组成是Ca主导型水向Na主导型水演化的中间状态。

The chemical types of the shallow groundwater in Hohhot basin were classified into dominant ion types and non-dominant ion types according to whether the percentage of milliequivalent of major ions exceeded50%.The chemical characteristics of shallow groundwater was studied by Piper diagram and ion ratios on the basis of that classification.The results indicated that the chemical types of cation in shallow groundwater showed strong horizontal zonation,and the anion type of HCO3 dominant groundwater was widely distributed in study area.The Ca dominant groundwater with low TDS was also HCO3 dominated,which was controlled by lixiviation.The formation of Na dominate groundwater with HCO3 dominated of anion distributed in the west-central part of the Daheihe alluvial-lacustrine plain was affected by the cation exchange and desulfurization.The lacustrine sedimentary environment provided the favorable material foundation and environment condition;The chemical composition of non-dominant cation type and Mg dominant groundwater was the intermediate state of the evolution from the Ca dominant groundwater to the Na dominant groundwater.