Radionuclide dating was carried out on 1 cm thick samples following freeze-drying, homogenization and placement in cylindrical transparent polystyrene containers that were sealed with an aluminum-composite foil in order to keep the samples Radon-tight. The activity concentrations of the radionuclides were measured gamma-spectrometrically after at least 3 weeks using Canberra-Eurisys Broad Energy Germanium (BEGe-5030) detectors. The activity concentrations were calculated with the LabSOCS (Canberra) calibration software taking into account the self-absorption of γ-rays in both samples and beakers as well as the summation-effects due to simultaneous emissions of several gammas from one nuclear decay. Measuring time was up to 24 h per sample until counting uncertainties of <5 % were achieved.