芙蓉洞洞穴水离子浓度和元素比值变化特征及其环境意义

摘要

On the basis of monitoring data on geochemistry of the spring water, drip water and pool water in the Furong Cave from Mar. 2006 to Feb. 2009 and the local instrumental data, it is concluded that the concentration of Sr2+ , Ca2+ , Mg2+ and their ratio depending not only on the variations in precipitation and temperature but also on the overlying rock and soil. The average Ca2+ concentration in No. 6 spring water out of the cave is 45. 81 mg/L, but the average Ca2+concentration in No. 1 and No. 3 drip water in the cave is 64. 59 mg/L, but the average Ca2+concentration in No. 2 and No. 4 pool water drops to 24. 74 mg/L(fall by about 61. 7%), leading by precipitation of Ca2+. The variations in Mg2+ and Sr2+ concentrations in the spring water, drip water and pool water are of no difference with that of the Ca2+. In each water, the Cl- concentration ranges little, averaging 1. 72 ±0. 2 mg/L. The interaction time between the karst water and the bedrocks, and the prophase deposition during the transference of karst water, have important impact on the contents of each kind of element and ion. The variations of Mg/Ca and Sr/Ca, controlled by the prophase deposition in dry season and the corrosion of rocks in rainy season as well as the dilution of rainwater, could responding to extreme, drought or flood, climate events.%通过对芙蓉洞2006年3月-2009年2月期间泉水和洞穴滴水、池水的地球化学指标监测,结合当地的器测数据,初步认为洞穴滴水的Sr2+、Ca2+、Mg2+浓度及其比值既取决于环境降水和温度的变化,也受到上覆岩土作用的影响.芙蓉洞外山上的6#泉水Ca2+平均浓度为45.81mg/L,洞内1#、3#滴水Ca2+的平均浓度64.59 mg/L,2#和4#池水中由于Ca2+沉积,浓度下降到24.74 mg/L,下降了大约61.7%.Mg2+和Sr2+的浓度在泉水、滴水和池水中的变化规律与Ca2+基本一致.各种水体中C1-的浓度变化幅度较小,平均浓度为1.72 ±0.2 mg/L.岩溶水与基岩作用时间长短以及运移过程中Ca2+的前期沉积作用对各元素与离子含量变化具有重要作用.旱季Ca2+的前期沉积作用和雨季基岩的溶蚀及雨水的稀释作用主导着岩溶水中Mg/Ca与Sr/Ca的变化,这些指标能对于旱和洪涝等极端气候事件做出响应.