Preservation of Midlatitude Ice Sheets on Mars

A. M. Bramson, S. Byrne, J. Bapst

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Excess ice with a minimum age of tens of millions of years is widespread in Arcadia Planitia on Mars, and a similar deposit has been found in Utopia Planitia. The conditions that led to the formation and preservation of these midlatitude ice sheets hold clues to past climate and subsurface structure on Mars. We simulate the thermal stability and retreat of buried excess ice sheets over 21 Myr of Martian orbital solutions and find that the ice sheets can be orders of magnitude older than the obliquity cycles that are typically thought to drive midlatitude ice deposition and sublimation. Retreat of this ice in the last 4 Myr could have contributed ~6% of the volume of the north polar layered deposits (NPLD) and more than 10% if the NPLD are older than 4 Myr. Matching the measured dielectric constants of the Arcadia and Utopia Planitia deposits requires ice porosities of ~25–35%. We model geothermally driven vapor migration through porous ice under Martian temperatures and find that Martian firn may be able to maintain porosity for timescales longer than we predict for retreat of the ice.

Original languageEnglish (US)
Pages (from-to)2250-2266
Number of pages17
JournalJournal of Geophysical Research: Planets
Volume122
Issue number11
DOIs
StatePublished - Nov 2017

Keywords

  • Mars
  • ice
  • midlatitudes
  • obliquity cycles
  • sublimation lag
  • thermal stability

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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