David P Gillikin, Union College, Geology, Schenectady, NY, United States, Heidi O'Hora, University of Michigan, Earth and Environmental Sciences, Ann Arbor, MI, United States, David Hays Goodwin, Denison University, Geosciences, Granville, OH, United States and Alan D Wanamaker, Iowa State University, Geological and Atmospheric Sciences, Ames, IA, United States