Affiliation: | Department of Earth and Atmospheric Sciences, Purdue University, 550;Stadium Mall Drive, West Lafayette, IN 47907-2051, USA. E-mail: Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241;Broad Branch Road, N.W., Washington DC 20015, USA Department of Geosciences, State University of New York - Stony Brook, Stony Brook, NY 11794-2100;, USA Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ,;UK AIR-Worldwide Corp., 101;Huntington Ave., 22nd Fl., Boston, MA 02199, USA |