乌拉盖盆地第四系潜水水化学特征及成因分析

Chemical Characteristics and Genesis of Quaternary Phreatic Water in Wulagai Basin

为查明乌拉盖盆地第四系潜水化学特征及成因,应用化学参数统计、相关系数矩阵分析、派珀三线图解法、Gibbs图解法和离子比例系数分析等方法对乌拉盖盆地采取的45组潜水水样测试结果进行了数据分析。研究结果表明:乌拉盖盆地第四系潜水呈中性偏碱性水,溶解性总固体(TDS)浓度与总硬度大部分地区较低,基本为淡水和低硬度水,仅在径流排泄区及中部波状高平原边缘弱径流区一带溶解性总固体浓度与总硬度偏高;潜水水化学类型、各种主要离子及溶解性总固体浓度的变化具有规律性,各种主要离子与溶解性总固体浓度沿径流路程逐渐增高,越靠近排泄区越高,水化学类型由HCO_(3)-Na·Ca型水逐渐演变为HCO_(3)·Cl-Na·Mg、Cl-Na·Mg和HCO_(3)·SO_(4)-Na·Mg型水;乌拉盖盆地潜水的化学成分来源主要为硅酸盐和碳酸盐矿物的溶解,其形成与变化主要受溶滤作用、阳离子交替吸附作用的影响,靠近排泄区或弱径流区一带,蒸发浓缩作用为主要影响因子,大气降水的影响可忽略不计,少数地段受人类活动的影响。

To ascertain the characteristics and causes of Quaternary phreatic water chemistry in Wulagai basin,the data of 4 phreatic water samples taken in Wulagai basin was analyzed by means of chemical parameter statistics,correlation coefficient matrix analysis,Piper diagram,Gibbs diagram and ion proportion coefficient analysis.The research indicated that Quaternary phreatic water of Wulagai basin was neutral and alkaline water,the total dissolved solids and total hardness were lower in most areas,which was fresh water and low hardness water,only in the runoff discharge area and the weak runoff in the edge of the central undulating high plain,the total dissolved solids and total hardness were relatively high,the chemical types of phreatic water,the contents of main ions and total dissolved solids change regularly,the contents of main ions and total dissolved solids gradually increased along the runoff path,and the closer the area to the discharge area,the higher the contents of main ions,and the hydrochemical type gradually evolved from HCO_(3)-Na·Ca water to HCO_(3)·Cl-Na·Mg,Cl-Na·Mg,HCO_(3)·SO_(4)-Na·Mg water.The dissolution of aluminosilicate and carbonate minerals were the main sources of chemical composition of phreatic water in Wulagai basin,whose formation and change were controlled by leaching and cation alternating adsorption.The effect of concentration was relatively large,basically not affected by atmospheric precipitation,and a few sampling points were also affected by human activities.