Measurements of the concentrations of dichlorodifluoromethane CFCtritium 3Hand sulfur hexafluoride SF6 in groundwater from basaltic aquifers in Jeju Island, Korea, demonstrate a terrigenic source of SF6. This work has been carried out on samples from two aquifers, Blumau, an aquifer of fluvial origin, in Austria, and the East Midlands Triassic Sandstone in the UK. Conceptual models of shallow groundwater flow and solute transport in this system have been developed but are difficult to evaluate using physical characterization or short-term tracer methods due to extreme spatial variability in hydraulic properties. An aliquot of approximately 30 cm 3 of seawater is introduced into a glass stripping chamber where the dissolved gases are purged with purified gas, and the evolved CFCs are concentrated in the same cold trap. We present the methods employed for arriving at an age-date for a given sample of argon degassed from groundwater.
The injection and detection protocols of the radiotracers are explained.
Dating of Young Groundwater