1. 1 Geological Surveys of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark
2. 2 INEOS Energy Teknikerbyen 5, DK-2850 Virum, Denmark
3. 3 Copenhagen University, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark
4. 4 School of Geographical and Earth Sciences, University of Glasgow, University Avenue, Glasgow G12 8QQ, Scotland