1. Geology Department, Western Washington University, Bellingham, Washington 98225, USA
2. Department of Geoscience, University of Iowa, Iowa City, Iowa 52242, USA
3. Department of Earth and Planetary Sciences, University of California, Davis 95616, California, USA
4. Department of Geology and Natural Resources, Institute of Geosciences, University of Campinas (UNICAMP), Campinas 13083-855, Brazil
5. Department of Geological Sciences, Stanford University, Stanford, California 94305, USA
6. School of the Environment, Washington State University, Pullman, Washington 99164, USA