CO_2在洞穴空气和滴水水文过程中的变化——以贵州织金洞为例

Variations of CO_2 in Dripwater Hydrological Process and Air in Zhijin Cave in Guizhou Province

通过对织金洞水汽CO_2为期一年(2015年1月至2015年12月)的监测,将洞穴空气中的CO_2(P_(CO_2(a)))和洞穴滴水中CO_2(P_(CO_2(w)))分压进行比较。分析结果显示:各监测点P_(CO_2(a))均具有明显的季节变化,表现为夏季高,冬季低;各监测点P_(CO_2(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P_(CO_2(a))明显;同时玉兔宫的P_(CO_2(w))变化相对稳定,其CO_2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CO_2、降水土壤微生物和植物呼吸等因素共同耦合的结果。

Carbon dioxide(C02)was studied in Zhijin cave in Guizhou province during a one-year period from January2015to Decemner2015.Partial pressures of the C02corresponding to aqueous carbonates Pc〇2(y}compared with the partial pressure in cave air,f*c〇2(a).Analysis results show:Pc〇2(-a^of each monitoring point has obvious sea-sonal variation,which is high in summer and low in winter.The seasonal variation of Pc〇2(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 f*c〇2⑷significantly;At the same time the Moon Palace f*c〇2⑷were relatively stable,the C02source may be located deeper epikarst zone or vadose zone;The Sic value of the water drop point of Zhijin cave is more than0,mainly in the sedimentary environment.But in different seasons,the change of the value is very dif-ferent,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 rel-atively low summer Sic is mainly on the roof covering the soil C02,precipitation,soil microorganism and plant res-piration factors of common coupling results.