Here we report 14CDOC and 81Kr groundwater dating results together with hydrochemical data, stable water isotopes, noble gases and out-diffusion experiments that indicate that the thermal groundwater consists of at least two groundwater sources: a formerly unknown young groundwater component with apparent water ages between 9,800 and 18,700 a and an old groundwater component, which shows an apparent water age of up to approximately 300 ka. The results of the out-diffusion experiments with core material from the Upper Jurassic aquifer (UJA) suggest that diffusion processes between rock-matrix water and more mobile fracture water represent a controlling mechanism for groundwater flow and the observed extended apparent groundwater ages within the UJA.
Theis Winter & Florian Einsiedl (2022): Combining 14CDOC and 81Kr with hydrochemical data to identify recharge processes in the South German Molasse Basin; Vol. 612,
J. of Hydrology,
ISSN 0022-1694,
https://doi.org/10.1016/j.jhydrol.2022.128020