Ra-Rn isotope dating of the Bad Brambach mineral waters

A new interpretation of Ra and Rn measurements in mineral waters of Bad Brambach is described. This interpretation is based on a simple model for groundwater dating which is derived by some simple assumptions from a transport equation. Some assumptions of the model are not proved by experiments until now. An application of the model to the mineral waters of Bad Brambach gives reasonable results and demonstrates the usefulness of the derived formula. The mineral waters of shallow springs have residence times in a Ra-rich zone of 30-200 days. Waters of deep wells are probably decended from another part of the aquifer system. They have residence times of about 600 days in a Ra-rich zone. (author)