title: An ice age recorded in the polar deposits of Mars.
abstract: Layered ice deposits at the poles of Mars record a detailed history of accumulation and erosion related to climate processes. Radar investigations measure these layers and provide evidence for climate changes such as ice advance and retreat. We present a detailed analysis of observational data showing that ~87,000 cubic kilometers of ice have accumulated at the poles since the end of the last ice age ~370,000 years ago; this volume is equivalent to a global layer of ~60 centimeters. The majority of the material accumulated at the north pole. These results provide both a means to understand the accumulation history of the polar deposits as related to orbital Milankovitch cycles and constraints for better determination of Mars' past and future climates.
authors.affiliation: Department of Space Studies, Southwest Research Institute, Boulder, CO 80302, USA. isaac@boulder.swri.edu.
authors.forename: Isaac B
authors.initials: IB
authors.lastname: Smith
authors.affiliation: Department of Space Studies, Southwest Research Institute, Boulder, CO 80302, USA.
authors.forename: Nathaniel E
authors.initials: NE
authors.lastname: Putzig
authors.affiliation: University of Texas Institute for Geophysics, Jackson School of Geosciences, University of Texas, J. J. Pickle Research Campus, Austin, TX 78758, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Holt
authors.affiliation: Planetary Science Division, Southwest Research Institute, Boulder, CO 80302, USA. McDonnell Center for the Space Sciences and Department of Earth and Planetary Sciences, Washington University, St. Louis, MO 63130, USA.
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Phillips