1. Department of Geography, University of California Santa Barbara, Santa Barbara, CA, USA.
2. Department of Earth and Environmental Sciences, St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, USA.
3. Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA, USA.
4. Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
5. Department of Earth and Atmospheric Sciences, Indiana University, Bloomington, IN, USA.
6. Department of Earth Science, University of California Santa Barbara, Santa Barbara, CA, USA.