张掖盆地地下水锶元素地球化学特征研究

Study on Sr Geochemistry Characteristics of Groundwater in Zhangye Basin

为研究张掖盆地地下水中锶元素的地球化学特征,以盆地内15个钻孔中28组地下水水样的化学测试数据为基础,刻画盆地内地下水中Sr^(2+)的分布规律,并分析了Sr^(2+)与地下水中主要指标的相关性。结果表明,地下水Sr^(2+)浓度沿地下水的流动路径呈现出明显的水化学特征演化规律,总体上表现为山前冲洪积扇区浅层和深层地下水Sr^(2+)浓度普遍大于中部细土平原区的浅层和深层地下水Sr^(2+)浓度,SO_4·HCO_3型地下水中Sr^(2+)浓度大于HCO_3·SO_4型地下水中Sr^(2+)浓度值,浅层地下水中Sr^(2+)浓度大于深层地下水中Sr^(2+)浓度。Sr^(2+)浓度与TDS、TH及Ca^(2+)、Na^+、Mg^(2+)、HCO_3^-、SO_4^(2-)浓度正相关,表明地下水中Sr^(2+)主要来自水—岩相互作用过程中含锶矿物的溶解。研究成果开拓了地下水循环与演化研究的思路,提供了一种分析水文地质问题的新方法。

This paper analyzes the distribution of Sr2＋ concentration and the relationship between the chemical parameters and Sr2＋ concentration in the groundwater based on the chemical test data of 28 groundwater samples of 15 drill holes from the Zhangye basin to study the geochemical feature of Sr2＋ in the groundwater. The results reveal that the Sr2＋ concentration in the groundwater show an obvious evolution regulation of hydrochemical characteristics along the path of the groundwater recharge and discharge. The Sr2＋ concentration in the shallow and deep groundwater of the piedmont alluvial is greater than that in the central plains district. The Sr2＋ concentration in the SO4·HCO3 groundwater is greater than that in the HCO3·SO4 groundwater, and the Sr2＋ concentration in the shallow groundwater is greater than that in the deep groundwater. The Sr2＋ concentration positively correlates with TDS、TH、Ca2＋、Na＋、Mg2＋、HCO-3、SO2-4 concentration in the groundwater. Thus, the Sr2＋ concentration in the groundwater is mainly from the solution of Sr-bearing minerals during the water-rock interactions. This study develops a new way for researching the recycle and evolution of groundwater, and analyzing the problem of hydrology geology.