Aaron Grey Stubblefield, Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY, United States, Timothy T Creyts, Columbia University-LDEO, Palisades, NY, United States, Jonathan Kingslake, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States and Marc W Spiegelman, Columbia University, New York, NY, United States