数理统计方法在区域浅层地下水水文地球化学研究中的应用

Application of Mathematical Statistics Methods on the Study of Hydrogeochemistry for the Shallow Groundwater

通过对四川盆地大量浅层风化带裂隙水水化学数据的描述性分析、相关分析、因子分析,结合盆地地质—水文地质条件,分析和研究了浅层风化带裂隙水化学成分分布特征及形成作用。结果表明:区内浅层风化带裂隙水中主要阴阳离子为HCO3-和Ca2+,HCO3-、Ca2+、Mg2+在地下水中含量相对稳定,尤其是HCO3-绝对含量较大,相对含量差别不大;Na++K+、SO24-、Cl-在地下水中含量变化较大,是随环境因素变化的敏感因子;水化学成分特征的形成受大气降水和含水系统中岩石矿物成分的影响;总溶解固体值TDS<1 g/L的淡水在区内大面积分布,TDS值总体呈现出由盆地边缘向盆地中心的递增关系,表明溶滤作用由盆地周围向盆地中心的递增特点,但局部地区TDS值受大气降雨的影响。

Mathematical statistical methods, as supplements for computer modeling, have many advantages in the study of hydrogeochemistry for the shallow groundwater. Descriptives, correlation and factor analyses have been carried out for the water quality data of the groundwater samples from the shallow weathering zone of red beds in the Sichuan basin. It was found that the dominant cation and anion are HCO3^- and Ca^2 ＋ respectively; the concentrations of HCO3^- , Ca^2＋ and Mg^2＋ are in stabilization and in particular, the concentration of HCO3^- are steady with high values ; the concentrations of Na^ ＋ ＋ K ^＋ , SO4^2- and Cl^ - have high variations and are sensi- tive to many environmental parameters ; the geochemical composition of the water samples were controlled by at- mospheric precipitation and the mineral composition of the rock; freshwater with TDS 〈 1 g/L covers the most area with low TDS in the skirt and high TDS values in the central area of the basin and also TDS in local areas was controlled by atmospheric precipitation.