滇中高原岩溶关键带典型含水系统水化学特征及成因分析

岩溶关键带水文地球化学过程的研究对于科学认识其内部的演化环境与结构特征具有重要意义。岩溶水是水-岩作用后主要的信息载体, 定量分析其水化学特征及成因是揭示岩溶关键带含水系统介质环境与水动力条件的有效手段。以滇中高原岩溶关键带3个典型岩溶含水系统为研究对象, 通过对不同含水系统出露的岩溶泉进行野外采样与室内测试, 综合采用数理统计分析、水化学图解、离子比例系数与水文地球化学模拟等方法, 深入剖析了各含水系统岩溶水水化学组分特征、成因作用和含水层介质特性, 并对关键带中水循环与水化学的内在联系及规律进行了探讨。结果表明: ①HCO₃-、Ca2+是各含水系统岩溶水中含量最高且来源稳定的离子组分, Mg2+是控制各含水系统水化学类型异化的关键因素; ②碳酸盐岩类的岩石风化、矿物溶解是各含水系统内岩溶水化学组分特征的主要成因作用, 岩溶水对华宁水系统含水层的溶蚀作用仍在发生, 阳离子吸附交替与硅酸盐岩类的风化溶解是区域岩溶水中Na+、K+的重要来源; ③区域岩溶的发育强度、岩溶含水层的出露条件及含水介质岩性与连通性共同塑造了滇中高原岩溶关键带不同含水系统地下水化学特性。研究成果丰富了对滇中高原岩溶关键带水文地球化学过程的认识, 为区域岩溶水资源的开发、利用与保护提供基于水化学的证据支撑。 

Hydrochemical characteristics and genesis analysis of typical aquifer system in karst critical zone of Central Yunnan Plateau

The study of hydrogeochemical processes in the karst critical zone (KCZ) is of great significance for the scientific understanding of their internal evolutionary environment and structural characteristics. Karst groundwater is the main information carrier after water-rock interactions. Quantitative analysis of its hydrochemical characteristics and causes is an effective means to reveal the medium environment and hydrodynamic conditions of the aquifer system in the KCZ. In this paper, three typical karst aquifer systems in the KCZ of the central Yunnan Plateau were taken as the research objects. Through field sampling and laboratory testing of karst springs exposed by different aquifer systems, mathematical statistics analysis, hydrochemical diagram, ion ratio coefficient and hydrogeochemical simulation were comprehensively used to deeply analyze the characteristics of hydrochemical components, genesis and aquifer medium of karst groundwater in each aquifer system; the internal relationship and law between the water cycle and hydrochemistry in the key belt were discussed. The results showed that: ①HCO₃- and Ca2+ were the highest and most stable ion components in regional karst groundwater, and Mg2+ was the key factor controlling the alienation of hydrochemical types in each aquifer system; ②The rock weathering and mineral dissolution of carbonate rocks were the main causes of the chemical composition characteristics of karst water in each aquifer system, and karst groundwater dissolution on the aquifer of the Huaning aquifer system was still occurring. The alternation of cation adsorption and the weathering and dissolution of silicate rocks were the main sources of Na+ and K+ in regional karst groundwater; ③The development intensity of regional karst, the exposed condition of karst aquifers and the lithology and connectivity of aquifer media jointly shaped the groundwater chemical characteristics of different aquifer systems in the KCZ of the Central Yunnan Plateau.