Evaluation of soil zone processes and a novel radiocarbon correction approach for groundwater with mixed sources

Estimation of Groundwater Residence Time Using Radiocarbon and Stable Isotope Ratio in Dissolved Inorganic Carbon and Soil CO2

“…Assuming bedrock carbonates as the other contributor to the DIC (hard-water effect) with a δ 13 C value of ∼0 ± 2‰ (Ripperdan 2001) and free from 14 C, we correct its contribution to the radiocarbon ages calculating the factor q (Equation 3, Table 3). The factor q can also be affected by dissolution of soil carbonate from shallow zones with 14 C content neither zero nor modern (e.g., Solder and Jurgens 2020) though the deep soil carbonates are mostly free from 14 C. The contribution from soil carbonates and carbonate nodules are neglected in the present case as the contribution from dissolution of such carbonates in alluvial settings with relatively fast recharge is expected to be low. However, this needs to be tested measuring 14 C content in soil DIC and soil carbonate.…”