Brian J Anderson, Johns Hopkins Univ, Laurel, MD, United States, Regupathi Angappan, Johns Hopkins University, Department of Earth and Planetary Sciences, Baltimore, MD, United States, Sarah K. Vines, University of Texas at San Antonio, San Antonio, TX, United States, Sabine Stanley, University of Toronto, Toronto, ON, Canada and Robin J Barnes, JHU/APL, Laurel, MD, United States