1. Geosciences Department, Warner College of Natural Resources, Colorado State University, Fort Collins, Colorado, U.S.A.
2. Department of Earth and Space Sciences, University of Washington, Seattle, Washington, U.S.A.
3. Scripps Institution of Oceanography, University of California, San Diego, California, U.S.A.
4. Department of Geosciences, Penn State University, University Park, Pennsylvania, U.S.A.
5. Department of Earth and Planetary Sciences, Washington University, St. Louis, Missouri, U.S.A.
6. Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, U.S.A.