[Spatial and Temporal Variation Characteristics of Drip Water Hydrogeochemistry in the Xueyu Cave of Chongqing and Its Implications for Environmental Research].

Geochemical indexes of drip water were monitored to unveil their seasonal variability and response mechanism to the external climate from March 2015 to March 2017 at four sites in Xueyu Cave, Chongqing municipality. The results showed that four drips show a significant difference in ion concentration and discharge despite all sites having simple HCO3--Ca2+ waters and being super-saturated with respect to calcite. Being subject to geochemical processes, such as bedrock dissolution, dilution, and prior calcite precipitation (PCP), the geochemistry indexes, such as Ca2+, Mg2+, HCO3-, EC, pH, pCO2, and SIc, at the four sites showed extraordinary seasonal variations and could perfectly respond to external climate events. Due to the difference of migration pathways and PCP intension, different types of drip water had diverse seasonal variations in Mg/Ca. Affected by soil CO2 content and hydrodynamic conditions, the δ13CDIC of all sites had correlations with external temperature or precipitation. On a short time scale, the δ13CDIC values reflected the precipitation amount in the site with its flow path controlled by conduit flow.