1. Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, 1350 Copenhagen K, Denmark
2. Nano-Science Center, Department of Chemistry, University of Copenhagen, 2100 Copenhagen Ø, Denmark
3. Department of Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
4. Department of Earth Sciences, Utrecht University, 3508TA Utrecht, Netherlands
5. Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
6. Department of Plant and Environmental Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark