CO2在洞穴空气和滴水水文过程中的变化——以贵州织金洞为例

摘要

Carbon dioxide(CO2) was studied in Zhijin cave in Guizhou province during a one-year period from January 2015 to Decemner 2015.Partial pressures of the CO2 corresponding to aqueous carbonates PCO2(w)compared with the partial pressure in cave air,PCO2(a).Analysis results show:PCO2(a) of each monitoring point has obvious seasonal variation, which is high in summer and low in winter.The seasonal variation of PCO2(w)in each monitoring point is similar to that in summer.A high summer, winter low change characteristics was also shown.But its degree of change is not PCO2(a) significantly;At the same time the Moon Palace PCO2(w) were relatively stable, the CO2 source may be located deeper epikarst zone or vadose zone;The SIc value of the water drop point of Zhijin cave is more than 0, mainly in the sedimentary environment.But in different seasons, the change of the value is very different, which is high in winter and low in summer;At the same time, the SIc value of the winter is more than that of the deposition line, which may be controlled by the PCP process(i.e.prior calcite precipitation).While the relatively low summer SIc is mainly on the roof covering the soil CO2, precipitation, soil microorganism and plant respiration factors of common coupling results.%通过对织金洞水汽CO2为期一年(2015年1月至2015年12月)的监测,将洞穴空气中的CO2(PCO2(a))和洞穴滴水中CO2(PCO2(w))分压进行比较.分析结果显示:各监测点PCO2(a)均具有明显的季节变化,表现为夏季高,冬季低;各监测点PCO2(w)的季节变化与相似,也呈现出夏季高,冬季低的变化特征;但变化程度没有PCO2(a)明显;同时玉兔宫的PCO2(w)变化相对稳定,其CO2来源可能位于更深部的表层岩溶区或包气带;织金洞滴水点SIc值均大于0,主要以沉积环境为主;但不同季节其变化值有很大不同,表现为冬季高,夏季低;同时冬季SIc值基本位于沉积线以上,可能是受PCP过程控制.而夏季SIc相对较低,主要是洞顶上覆土壤CO2、降水土壤微生物和植物呼吸等因素共同耦合的结果.