白云岩喀斯特洞穴水理化性质特征及其环境指示研究:以绥阳双河洞为例

Study on the physicochemical characteristics and environmental indication of dolomite karst cave water in the Shuanghe Cave, Guizhou Province

为揭示白云岩岩层中发育洞穴中的洞穴水地球化学特征的动态变化特征、控制因素及其环境意义,从2015年4月至2015年9月对绥阳双河洞洞穴水的水化学指标进行了为期6个月的动态监测。结果表明:(1)双河洞洞穴水的水化学类型主要为HCO_3~–-Ca^(2+)-Mg^(2+)和SO_4^(2-)-HCO_3~–-Ca^(2+)-Mg^(2+)型水,阴离子中HCO_3~–和SO_4^(2-)是优势离子,阳离子中Ca^(2+)、Mg^(2+)为优势离子;(2)洞穴滴水中方解石饱和指数(SI_c)、白云石饱和指数(SI_d)之间有显著正相关性且与水样中气相二氧化碳分压对数(lg pCO_2)成反比;(3)洞穴水滴率、滴量、pH对气候有一定的响应,其地球化学指标具有显著的季节效应;(4)洞穴滴水中的电导率(EC)与Ca^(2+)离子浓度呈显著线性关系;(5)洞穴水中SO_4^(2-)和Cl^-含量占比(SC)对EC和总硬度(TH)之间的线性关系具有重要影响;(6)滴水中Sr/Ca、Mg/Ca比值表现出在略微滞后的情况下同步升高的现象,证明预先沉积作用(PCP)的存在。

In order to reveal the geochemical characteristics of dynamic variation of cave water and their controling factors and environmental significance, dynamic monitoring for a time of period of 6 months was carried out for the water chemistry indices of cave water from the Shuanghedong Cave, Suiyang, from June 2015 to September 2015. The results show thati （1） the Shuanghedong Cave water hydrochemical types are mainly HCO3-Ca2＋-Mg2＋ and SO2--HCO3-Ca2＋-Mg2＋ types, HCO3 and SO42- are the dominant anions, and Ca2＋, Mg2＋ are the dominant cations; （2） there is a significant positive correlation between Sic （the saturation index of calcite） and SId （the saturation index of dolomite） in the dripping water from the cave, and is inversely proportional to lg Pco2 （gaseous-phase carbon dioxide partial pressure logarithm） in the water samples; （3） water drop rate, drop amount and pH have a certain influence on climate, and the geochemical index shows a significant seasonal effect; （4） the EC and Ca2＋ ion concentrations in the water dripping from the cave are obviously linear; （5） the SC content of the cave water has a significant influence on the linear relationship between EC and TH; and （6） Sr/Ca and Mg/Ca ratios in cave water show a slight lag in the ease of synchronous elevation, indicating the existence of prior calcite precipitation （PCP）.