Groundwater Dating on Carbon-14 DIC: Identification and correction for mineralization of sedimentary organic carbon

摘要

Groundwater dating on ~(14)C of DIC requires identification of the source term indicative of the groundwater age, i.e. the portion of DIC in a groundwater introduced by recharge. Quantification of DIC from other sources is made mainly by means of the delta~(13)C value. On mineralization of sedimentary organic carbon (SOC), the delta~(13)C value of DIC generated cannot be distinguished from the source term, i.e. soil CO_2. In a groundwater where mineralization of SOC has occurred, the source term therefore cannot be identified by the delta~(13)C value of DIC. Furthermore, if the occurrence of mineralization of SOC is not recognized or is ignored, evaluation of the source term on the basis of the delta~(13)C value leads to overestimation of the groudwater age.