1. Hawaii Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI 96822, USA.
2. Department of Earth and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095–1567, USA.
3. Department of Geological Sciences, Arizona State University, Tempe, AZ 85287–1404, USA.
4. Department of Mineral Sciences, U.S. National Museum of Natural History, Smithsonian Institution, Washington, DC 20560–0119, USA.