岩溶洞穴地下水水化学特征及其地球化学敏感性比较——以贵州双河洞和织金洞为例

Study on the water chemical characteristics and geochemical sensitivity of underground water in different lithologic development-a case study of Shuanghe cave and Zhijin cave system in Guizhou Province

不同岩性发育下的洞穴,其洞穴地下水的地球化学敏感性具有明显的差异。对织金洞、双河洞系统的大风洞和皮硝洞等不同岩性的洞穴地下水进行地球化学敏感性研究,对比不同岩性的洞穴水化学特征差异及影响因素。结果表明:(1)3个洞穴地下水水化学阳离子以Ca^(2+)、Mg^(2+)为主,阴离子以HCO_3^-和SO_4^(2-)为主;织金洞水化学类型为Ca-HCO_3型,皮硝洞为Ca·Mg-SO_4·HCO_3型,大风洞为Ca·Mg-HCO_3型。(2)白云岩洞穴(双河洞)地下水Mg^(2+)/Ca^(2+)明显高于灰岩洞穴(织金洞),但在含膏白云岩洞穴(皮硝洞)中,地下水Mg^(2+)/Ca^(2+)比值由于受白云岩和石膏的风化溶解的影响,Mg^(2+)/Ca^(2+)变化幅度较大。(3)3个岩溶洞穴地下水地球化学敏感性中,阳离子以Ca^(2+)最强;阴离子在织金洞和大风洞地下水中以HCO_3^-较强,而在皮硝洞地下水中SO_4^(2-)则表现出较强的敏感性,各主量离子的地球化学敏感性总体上表现为皮硝洞>织金洞>大风洞。因此通过对不同岩性的洞穴地下水进行地球化学敏感性研究,以期为岩溶区地下水环境和保护岩溶水文生态提供科学的依据。

The geochemical sensitivity of the underground water in different lithologic development is obviously different. Through the geochemical sensitivity study of Zhijin cave and Shuanghe cave system in different lithology of unground water, to contrast the difference of cave water chemical characteristics and the influencing factors in different lithology. The resuhs show that ： ①Ca^2 ＋ , Mg^2＋ are the main chemical cation while SO4^2- - and HCO3- are the main chemical anion of the groundwater in the cave. Among them, the water chemistry type of Zhijin cave is Ca- HCO3 type; Pixiao Cave is Ca（Mg） -SO4 （HCO3 ） type; Dafeng Cave is Ca （Mg） -HCO3 type. ②The content of Mg^2＋/Ca^2＋ in dolomite cave （Shuanghe cave） groundwater was significantly higher than limestone cave （Zhijin cave）. However, the ratio of Mg^2＋/Ca^2 ＋ varies greatly in the gypsum dolomite cave （PiXiao cave） groundwater due to the influence of dolomite and gypsum weathering dissolution. ③According to the geochemical sensitivity of the three karst caves groundwater, Ca^2＋ was the strongest chemical cation, HCO3^- was the strongest chemical anion in Zhijin cave and Dafeng cave groundwater, while SO2- showed the strongest sensitivity in Pixiao cave groundwater. The geochemistry sensitivi- ty of the main icon in three cave groundwater was Pixiao cave 〉 Zhijin cave 〉 Dafeng cave. The study of the underground water geochemical sensitivity in different lithology can provide a scientific basis for the karst groundwater environment and the protection of karst hydrology.