1. Department of Mineral Sciences, Smithsonian Institution; National Museum of Natural History; Washington District of Columbia USA
2. Department of Earth Sciences; University of Cambridge; Cambridge UK
3. Department of Geography; University of Cambridge; Cambridge UK
4. Department of Earth Sciences; University of Oxford; Oxford UK
5. Department of Geological and Mining Engineering and Sciences; Michigan Technological University; Houghton Michigan USA
6. Institut für Geophysik, Instituto Geofisico de la Escuela Politecnica Nacional; Quito Ecuador
7. Institut für Geophysik; Universitat Hamburg; Hamburg Germany