Affiliation: | COMET, Department of Earth Sciences, Parks Road, Oxford, OX1 3PR, UK. E-mail:;Bullard Laboratories, Madingley Road, Cambridge CB3 0EZ, UK;Trofimuk United Institute, Koptyug Pr. 3, Novosibirsk 630090, Russia;Institute of Physics of the Earth, Russian Academy of Sciences, 123810 Moscow, B. Gruzinskaya 10, Russia |