Isotopic geothermometry and flow regimes in the Muschelkalk aquifer from northern Switzerland (Nagra deep drilling programme)

In the Muschelkalk aquifer of Northern Switzerland, two chemically different waters were found: a Na,Ca-Cl,SO4 type with low tritium and contents; and a Ca-SO 4 HCO 3 type which includes a modern water component. and values demonstrate that the dissolved sulphates are of Muschelkalk origin. Temperatures from l°0(CaC0o-H20) and 18 o(SO 4 -H 2 O) thermometry all lie within a narrow range (22-29°C and 43*58^C respectively). Application of geological constraints to this data indicates the existence of two separate groundwater-flow regimes within the study area.