豫西鸡冠洞不同尺度滴水水化学分析及对区域极端干旱的响应

论文对自2009年10月到2015年12月豫西鸡冠洞两处滴水：鲤鱼戏水（LYXS）和天宫冰灯（TGBD）进行了连续定点监测及取样分析,并结合2015年8月4—6日对其进行的暴雨监测,从不同时间尺度上分析了滴水的滴速、pH值、HCO^-₃、电导率、Ca²⁺、Mg²⁺、Ba²⁺、Sr²⁺、元素比值等指标的变化特征及其与降水的关系。结果表明：1）年际尺度上,鸡冠洞滴水的水化学特征响应ENSO循环引起的多雨年与干旱年降水的变化,其主要受控于土壤CO₂的溶解、上覆物质的淋滤、先期沉积作用（PCP）的强弱;2）季节尺度上,滴水受岩溶水运移路径、淋滤作用、水-岩反应时间及先期沉积作用等因素综合影响表现出明显的季节变化特征;3）在单场降雨尺度上,滴水的水化学特征都不同程度表现出随滴率的变化而变化的趋势,主要受到岩溶水的运移路径、活塞效应、稀释作用等因素影响,而与水-岩反应时间关系不大;4）受到2013年区域极端干旱后“老水”的滞留与2014年新降水的稀释作用影响,其滴水水化学指标的极端值出现在降水量有所回升的2014年。

Hydrogeochemical Characteristics of Dripwater in Jiguan Cave,Henan Province at Different Scales and the Response to Regional Extreme Drought Event

Geochemical dynamics of dripwater at LYXS and TGBD in Jiguan Cave were monitored from October 2009 to December 2015, and the rainstorm from August 4th to 6th in 2015 was monitored. Characteristics of the dripwater, including dripping speed, pH value, HCO^-₃, electrical conductivity, Ca²⁺, Mg²⁺, Ba²⁺, Sr²⁺, element ratio, and its relationship with precipitation, were analyzed at different time scales, and their responses to the extreme drought events were analyzed. The results showed that: 1) At inter-annual scale, the hydrochemical characteristics of dripwater responded to the precipitation difference between wet years and dry years. It was mainly controlled by the dissolution of soil CO₂, leaching effect and the intensity of prior calcite precipitation (PCP) effect. 2) Affected by the migration path of karst water, the leaching effect, the time of water-rock interaction and the PCP effect, there were obvious seasonal variations of the characteristics of dripwater. 3) At single rainfall scale, the hydrochemical characteristics of dripwater varied with the dripping rate. It was mainly influenced by the migration path of karst water, piston effect and dilution effect and had little relation with the time of water-rock interaction. 4) Affected by retention of the old water in the extreme drought year of 2013 and the dilution effect of the new precipitation in 2014, the extreme values of the hydrochemical indicators appeared in 2014 when the precipitation rebounded. The decrease rates of EC, HCO^-₃, Ca²⁺, Mg²⁺, Ba²⁺, Sr²⁺, were 12%, 35%, 35%, 28%, 89% and 95%, respectively.