喀斯特流域水化学特征及水-岩作用分析——以后寨河流域为例

Analysis of Hydrochemical Characteristics and Water-Rock Interaction in Karst Basin——A Case Study of Houzhai River Basin

本文选取后寨流域作为研究对象,基于对水体中主要离子的主成分分析和离子比值分析,研究丰枯期水化学特征及水-岩作用程度。研究表明,水体中各离子的主成分荷载值和站点得分能够辨识流域内主要水化学成分及水-岩（T_2g^2、T_2g^3）作用特征,丰水期主成分反映碳酸盐岩可溶性和水动力条件组合的影响,枯水期主成分反映蒸发岩和水动力条件组合的影响。水流作用强的石灰岩地区,管道发育,水流变化迅速,水体中离子浓度低。随着白云岩含量增加或水流作用减弱,水体中离子含量增大。枯水期从上游至中下游水流作用减弱,蒸发作用增强。

The principal component analysis（ PCA） and the ion ratio analysis on water irons were applied for investigation of hydrochemical characteristics and water-rock interaction in dry and wet periods in the Houzhai River Basin. The research shows that the PCA load value and its site scores can be used to identify the main chemical components and thus water-rock interaction features of the lithology of T_2 g^2 and T_2 g^3 in the study catchment. During the wet period,the identified main components reflect the combination influence of dissolution of carbonate rocks and hydrodynamic condition; in dry season,they reflect the combination influence of evaporite rocks and hydrodynamic condition. Since well-developed conduits and rapid flow in limestones areas,iron concentration is low. However,as the dolomite area increases or the flow decreases,the iron concentration increases. During the dry period,the evaporite rocks take a more significant role on the iron concentration as the flow decreases from upstream to downstream.