The chronology of the top part of the core SIS11-3 is based on excess 210Pb and anthropogenic gamma emitting radionuclides. The analyses of samples down to 66 cm depth were conducted by gamma spectrometry with a reverse electrode coaxial HPGe detector. The efficiencies for the factory characterized detector were calculated using LabSOCS (Laboratory SOurceless Calibration System), a Genie 2000 software calibration tool, based on defined sample to detector geometry and sample density and composition.Due to the low masses of the 1 cm sediment core increments, each time three freeze-dried 1 cm intervals were pooled, i.e. three of the small sample containers were placed side by side in a triangular arrangement onto the detector front window. Because of the long measurement times needed and limitations in detector time, every second of these pooled samples was measured, plus an additional sample at 60-63 cm.

Gamma spectrometry was performed in the Bremen State Radioactivity Measurements Laboratory (Landesmessstelle für Radioaktivität), Institute of Environmental Physics, University of Bremen.All activity concentrations are reported per mass dry sediment.For the sediment chronology, the piecewise Constant Flux - Constant Sedimentation (CF-CS) model was applied. The deepest analyzed sample was excluded from the analysis, because it likely represents a much older material (below hiatus).