Widespread exposures of extensive clean shallow ice in the mid-latitudes of Mars

Journal of Geophysical Research: Planets
By: , and 



Although ice in the Martian midlatitudes is typically covered by a layer of dust or regolith, it is exposed in some locations by fresh impact craters or in erosional scarps. In both cases, the exposed ice is massive or excess ice with a low lithic content. We find that erosional scarps occur between 50° and 61° north and south latitude and that they are concentrated in and near Milankovič crater in the northern hemisphere and southeast of the Hellas basin in the southern hemisphere. These may represent locations of particularly thick or clean bodies of ice. Pits created by retreat of the scarps represent sublimation-thermokarst landforms that evolve in a manner distinct from other ice-loss landforms on Mars. New impact craters reveal that clean subsurface ice is widespread at middle- and high-latitudes in both hemispheres at depths less than 1 m. Both the depth to ice and the ice content appear to exhibit significant variability over tens to hundreds of meters. The lowest-latitude exposed ice is near 39°N and is at the edge of a region where impact exposures between 40° and 50°N are common, consistent with other indications of a high ice content. This lowest-latitude ice may be currently unstable and subliming. Impact craters on lineated valley fill excavate ice blocks that may represent the top of debris-covered glacial ice. Together, these landforms indicate widespread, clean subsurface ice at middle-latitudes on Mars. The distribution and properties of this ice could provide information about past climate conditions.

Publication type Article
Publication Subtype Journal Article
Title Widespread exposures of extensive clean shallow ice in the mid-latitudes of Mars
Series title Journal of Geophysical Research: Planets
DOI 10.1029/2020JE006617
Volume 126
Issue 3
Year Published 2021
Language English
Publisher Wiley
Contributing office(s) Astrogeology Science Center
Description e2020JE006617, 28 p.
Google Analytic Metrics Metrics page
Additional publication details