1. NORCE Norwegian Research Centre, Nygaardsgaten 112, 5008 Bergen, Norway
2. Department of Earth Science, University of Bergen, PO Box 7800, 5020 Bergen, Norway
3. Earth Science Analytics AS, Professor Olav Hanssens vei 7A, 4021 Stavanger, Norway
4. Department of Earth Sciences, Royal Holloway, University of London, Egham Hill, Egham TW20 0EX, UK