A prelanding assessment of the ice table depth and ground ice characteristics in Martian permafrost at the Phoenix landing site

Journal of Geophysical Research E: Planets
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Abstract

We review multiple estimates of the ice table depth at potential Phoenix landing sites and consider the possible state and distribution of subsurface ice. A two-layer model of ice-rich material overlain by ice-free material is consistent with both the observational and theoretical lines of evidence. Results indicate ground ice to be shallow and ubiquitous, 2-6 cm below the surface. Undulations in the ice table depth are expected because of the thermodynamic effects of rocks, slopes, and soil variations on the scale of the Phoenix Lander and within the digging area, which can be advantageous for analysis of both dry surficial soils and buried ice-rich materials. The ground ice at the ice table to be sampled by the Phoenix Lander is expected to be geologically young because of recent climate oscillations. However, estimates of the ratio of soil to ice in the ice-rich subsurface layer suggest that that the ice content exceeds the available pore space, which is difficult to reconcile with existing ground ice stability and dynamics models. These high concentrations of ice may be the result of either the burial of surface snow during times of higher obliquity, initially high-porosity soils, or the migration of water along thin films. Measurement of the D/H ratio within the ice at the ice table and of the soil-to-ice ratio, as well as imaging ice-soil textures, will help determine if the ice is indeed young and if the models of the effects of climate change on the ground ice are reasonable.

Publication type Article
Publication Subtype Journal Article
Title A prelanding assessment of the ice table depth and ground ice characteristics in Martian permafrost at the Phoenix landing site
Series title Journal of Geophysical Research E: Planets
DOI 10.1029/2007JE003067
Volume 114
Issue 3
Year Published 2009
Language English
Publisher American Geophysical Union
Publisher location Washington, D.C.
Contributing office(s) Astrogeology Science Center
Description 14 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Geophysical Research E: Planets
Other Geospatial Mars
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