HILLENBRAND, Ian, U.S. Geological Survey, Denver Federal Center, Denver, CO 80225; Department of Geosciences, University of Massachusetts, Amherst, 627 N Pleasant St, Amherst, MA 01003-9354, WILLIAMS, Michael L., Department of Geosciences, University of Massachusetts Amherst, 627 N Pleasant St, Amherst, MA 01003, PETERMAN, Emily, Department of Earth and Oceanographic Science, Bowdoin College, Brunswick, ME 04011, JERCINOVIC, M.J., Department of Geosciences, University of Massachusetts, Amherst, 627 N Pleasant St, Amherst, MA 01003-9354 and DIETSCH, Craig, Department of Geosciences, University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221-0013