1. Department of Geology and Geophysics; University of Wyoming; Laramie WY USA
2. Department of Geosciences, Warner College of Natural Resources; Colorado State University; Fort Collins CO USA
3. Department of Land, Air and Water Resources; University of California; Davis CA USA
4. Wollongong Isotope Geochronology Laboratory, School of Earth and Environmental Sciences; University of Wollongong; Wollongong Australia