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AGU: Geophysical Research Letters

 

Keywords

  • Pedestal craters
  • sublimation pits
  • ices

Index Terms

  • Planetary Sciences: Solid Surface Planets: Impact phenomena, cratering
  • Planetary Sciences: Solid Surface Planets: Ices
  • Planetary Sciences: Solid Surface Planets: Surface materials and properties
  • Atmospheric Processes: Climate change and variability

Abstract

GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L16104, 5 PP., 2008
doi:10.1029/2008GL034990

Martian pedestal craters: Marginal sublimation pits implicate a climate-related formation mechanism

Seth J. Kadish

Department of Geological Sciences, Brown University, Providence, Rhode Island, USA

James W. Head

Department of Geological Sciences, Brown University, Providence, Rhode Island, USA

Nadine G. Barlow

Department of Physics and Astronomy, Northern Arizona University, Flagstaff, Arizona, USA

David R. Marchant

Department of Earth Sciences, Boston University, Boston, Massachusetts, USA

Pedestal craters on Mars are defined by an outward-facing scarp forming a plateau perched tens of meters above the surrounding terrain. Their origin has been attributed to impact armoring of the surface and subsequent removal of inter-crater terrain by either eolian deflation or sublimation of an ice-rich substrate. We identified 2696 pedestal craters between ∼60°N and 60°S latitude; 98% are poleward of 33°N and 40°S. The majority of pedestal crater margins are smoothly sloped, but ∼3%, concentrated in Utopia Planitia and Malea Planum, display distinctive marginal pits. These pedestal crater scarps are anomalously tall (usually >80–100 m) and the pits resemble sublimation depressions seen on Earth and elsewhere on Mars, providing evidence for sublimation of volatiles in the scarp, where the armored surface has tapered. The pitted scarps provide insight into the origin of the general pedestal crater population, favoring formation via deposition of a volatile-rich substrate, impact armoring, and sublimation of intervening volatiles. Crater densities and overlapping pedestal craters suggest multiple periods of emplacement and loss of these climate-related, latitude-dependent deposits throughout the Amazonian.

Received 11 June 2008; accepted 16 July 2008; published 21 August 2008.

Citation: Kadish, S. J., J. W. Head, N. G. Barlow, and D. R. Marchant (2008), Martian pedestal craters: Marginal sublimation pits implicate a climate-related formation mechanism, Geophys. Res. Lett., 35, L16104, doi:10.1029/2008GL034990.

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