岩溶地下河水文地球化学对降雨的响应：以重庆雪玉洞地下河系统为例

通过对降雨条件下重庆雪玉洞地下河水文地球化学指标的监测,发现各种指标对降雨响应迅速,且存在相关性.采用主成分分析对各指标数据进行处理,提取能代表82.761%信息量的3个主成分,来分析降雨条件下岩溶地下河水文地球化学的特征及其成因.结果表明,以全Fe、全Mn、Al3+等浓度升高为代表的土壤淋失和以K+、Na+、Sr2+浓度降低、EC下降为代表的稀释效应,对水文地球化学特征变化的贡献率为41.718%,降雨加剧了岩溶区土壤的侵蚀,同时危及饮用水的安全,应引起相关部门的足够重视;岩溶水对白云岩的溶解和补给区农业活动、洞穴生物对水文地球化学特征变化的贡献率为29.958%;以Ca2+浓度升高为代表的岩溶水对灰岩的溶蚀作用对水文地球化学特征的贡献率为11.084%.

Formation of Geochemistry in Underground River Under Rainfall Conditions:An Example for Underground River at Xueyu Cave,Chongqing

Through the monitoring of geochemical indexes in underground river of Xueyu Cave in Chongqing under rainfall conditions, we found that all indexes responded quickly to rainfall, and there was a correlation among them. Each index was analyzed with the principal component analysis, three main components were extracted which can represent 82.761% of the information to reflect the formation of geochemistry in underground river under rainfall conditions. The results showed that the contribution rates of soil leaching represented as increased concentration of total Fe, total Mn and Al³⁺, and dilution effect represented as reduced concentration of K⁺, Na⁺ and Sr²⁺ to the change of geochemical characteristics were 41.718%, which should be paid more attentions for its great damage to karst soil and safety of drinking water. Karst water dissolution of dolomite and recharge area of agricultural activities, caverns were 29.958%, as for karst water on limestone dissolution represented as increased concentration of Ca²⁺ the contribution rate was 11.084%.