1. School of Biological, Earth and Environmental Sciences; University of New South Wales; Kensington NSW 2052 Australia
2. AOC Archaeology Group; St Margaret's Business Centre; Twickenham TW1 1JS UK
3. Department of Archaeology and Centre for Forensic Research; Simon Fraser University; Burnaby British Columbia V5A 1S6 Canada
4. Department of Earth Sciences; The Natural History Museum; London SW7 5BD UK