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影响洞穴次生化学沉积物-石笋的形成因素,包括降水、气温、水温和滴水的性质(如pH值、电导率、Ca2+、HCO3-浓度和滴率等)。通过对桂林盘龙洞8个滴水点的2个水文年的监测表明,洞穴滴水主要来源于大气降水(或土壤水),受控于水-土-岩的相互作用。洞穴滴水对大气降水的响应较快,具有季节性的变化特征。洞穴滴水的物理、化学特性受降水、洞顶基岩厚度及渗入水的滞留时间、滴率的快、慢的影响。洞穴滴水的温度变化不大,大约为19.4~21.2℃。年平均pH值为7.85。洞穴滴水的电导率、Ca2+、HCO3-浓度与气温、水温和滴水速率表现为正相关关系。在夏半年,大气降水量大,土壤湿度大,土壤中PCO2分压高,溶解的CaCO3多,表层带下渗岩溶水的岩溶作用强,滴水的电导率、Ca2+、HCO3-浓度增大,滴水中的碳酸盐沉积多;而在冬半年或冬季,其降水量小或少,滴水的电导率、Ca2+、HCO3-浓度降低,指示溶解的CaCO3少,表层带下渗岩溶水的岩溶作用弱,水中Ca2+离子含量低,滴水沉积物的沉积量或生长量减少。从大气降水到土壤水再到洞穴滴水这些过程可以看出,洞穴滴水形成的岩溶次生化学碳酸盐沉积物-石笋,可记录岩溶环境变化的信息,已成为研究岩溶地区过去环境变化记录的重要载体。
The formation of stalagmite, a secondary chemical deposit in caves, includes precipitation, temperature, water temperature and drip properties (such as pH, conductivity, Ca2 +, HCO3-, and drop rate). The monitoring of 8 hydrological years at 8 drip points at Panlong Cave in Guilin shows that the drip of caves mainly comes from atmospheric precipitation (or soil water) and is controlled by the water-soil-rock interaction. Cave drip response to atmospheric precipitation faster, with seasonal changes. The physical and chemical characteristics of cave drip water are influenced by precipitation, the thickness of bedrock bedrock, and the infiltration water retention time and drop rate. Cave drip temperature changes little, about 19.4 ~ 21.2 ℃. The average annual pH is 7.85. The conductivity, Ca2 + and HCO3- of cave drip water have a positive correlation with air temperature, water temperature and drip rate. In the summer half of the year, the atmospheric precipitation is large, the soil humidity is high, the partial pressure of PCO2 in the soil is high, the dissolved CaCO3 is more, and the karstification of the seepage karstification is stronger under the surface layer. The conductivity of the dripping water increases and the concentrations of Ca2 + and HCO3- increase, In the winter half year or winter, the precipitation is less or less, the conductivity of drip irrigation, Ca2 +, HCO3- concentration decreased, indicating less dissolved CaCO3, surface karstification under infiltration of karst water weak , The content of Ca2 + in water is low, and the deposition or growth of drip sediments is reduced. From the process of atmospheric precipitation to soil water to cave drip, it can be seen that the information about the change of karst environment can be recorded by the stratum of karst secondary chemical carbonate formed by cave drip, which has been recorded as the change of past environment in karst area Important carrier.