1. Universität Potsdam, Institut für Geowissenschaften, Potsdam-Golm, Germany. (corresponding author)
2. University of Cagliari, Cagliari, Italy and Geological Survey of Denmark and Greenland, Aarhus, Denmark.
3. University of Cagliari, Cagliari, Italy.
4. Norwegian Geotechnical Institute (NGI), Oslo, Norway.