1. Department of Applied Geology, Western Australian School of Mines, Curtin University, Bentley, GPO Box U1987, Perth, WA 6845, Australia
2. Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
3. School of Earth Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia