1. University of California, Merced, 5200 N. Lake Road, Merced, California 95340, United States
2. Brown University, 324 Brook Street, Geochemistry 139, Box 1846, Providence, Rhode Island 02912, United States
3. Kansas Geological Survey; 1930 Constant Avenue, Lawrence, Kansas 66047, United States
4. University of Wisconsin, Madison, 550 North Park Street, Madison, Wisconsin 53706, United States