Anna Mittelholz, University of British Columbia, Department of Earth, Ocean and Atmospheric Science, Vancouver, BC, Canada, Catherine Johnson, University of British Columbia, Department of Earth, Ocean and Atmospheric Sciences, Vancouver, BC, Canada, Roger J Phillips, Southwest Research Institute, Boulder, CO, United States, Benoit Langlais, Lab Planetologie Geodynamique, Nantes, France and Joshua M Feinberg, University of Minnesota, Minneapolis, MN, United States