Kathryn E. Snell (a), Henry C. Fricke (b), William C. Clyde (c) & John M. Eiler (a)
(a) Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA. E-mail: ksnell@caltech.edu
(b) Department of Geology, Colorado College, 14 E. Cache La Poudre, Colorado Springs, CO 80903, USA.
(c) Department of Earth Sciences, University of New Hampshire, 56 College Road, Durham, NH 03824, USA.