1. Department of Geological Sciences; Stockholm University; Stockholm Sweden
2. Department of Earth Sciences; University of Gothenburg; Gothenburg Sweden
3. Institute of Earth Sciences; University of Iceland; Reykjavík Iceland
4. School of Geosciences; University of Edinburgh; Edinburgh Scotland
5. Department of Earth Sciences; Uppsala University; Uppsala Sweden
6. Natural History Museum; University of Copenhagen; Copenhagen Denmark
7. Landsvirkjun; Reykjavík Iceland
8. NASA Ames Research Center, Earth Science Division; Moffett Field California USA
9. Karolinska Institutet; Stockholm Sweden