1. Research School of Earth Sciences, The Australian National University, Canberra ACT 2601 Australia
2. Research School of Engineering, The Australian National University, Canberra ACT 2601 Australia
3. Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3 Canada
4. Department of Earth Sciences, University College London, London, WC1E 6BT UK
5. School of Geosciences, The University of Sydney, Camperdown, NSW 2006 Australia
6. Department of Geosciences, SUNY Stony Brook, Stony Brook, NY 11794–2100 USA
7. CSIRO Energy, GPO Box 330, Newcastle NSW 2300 Australia