Department of Earth and Environmental Sceinces, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180 ; Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch rd. NW, Washington, DC 20015
Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch rd. NW, Washington, DC 20015
Department of Earth and Environmental Sceinces, Rensselaer Polytechnic Institute, 110 Eighth St., Troy, NY 12180