1. Formerly Aarhus University, HydroGeophysics Group, Department of Geoscience, Aarhus, Denmark; presently Geological Survey of Finland, Espoo, Finland.
2. University of Milano, Department of Earth Sciences “Ardito Desio,” Milano, Lombardia, Italy.
3. Jilin University, College of Geo-exploration Sciences and Technology, Changchun, China. (corresponding author)
4. Geological Survey of Denmark and Greenland, Copenhagen, Denmark.
5. Aarhus University, HydroGeophysics Group, Department of Geoscience, Aarhus, Denmark.