1. School of Environment, Earth and Ecosystem Sciences; The Open University; Walton Hall Milton Keynes MK7 6AA UK
2. CNRS UMR 6112 Laboratoire de Planétologie et Géodynamique de Nantes; Université de Nantes; 2 rue de la Houssinière 44322 Nantes France
3. School of Physical Science; The Open University; Walton Hall Milton Keynes MK7 6AA UK
4. Department of Geography; Loughborough University; Loughborough LE11 3TU UK
5. British Geological Survey, Environmental Science Centre, Keyworth; Nottingham NG12 5GG UK
6. Department of Geography and Tourism; University of Iceland; Askja, Sturlugata 7 IS-101 Reykjavík Iceland