Utopia Planitia Scallops, Polygons, and Boulders
NASA/JPL/University of Arizona
Utopia Planitia Scallops, Polygons, and Boulders
ESP_025620_2275  Science Theme: Glacial/Periglacial Processes
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This terrain is covered by pits and scallops (pits open on one side), perhaps due to collapse after sublimation of subsurface ice.

This full-resolution anaglyph sample shows that the surface is cut into many polygons about 10 meters wide, that form as ice expands and contracts with temperature changes. There are also many meter-scale boulders on the surface, which must be rocks rather than blocks of ice, or they would not be stable on the surface.

More than 10 meters thickness of ice must have sublimated from some areas. (Sublimation is the process of going from a solid directly to a gas). How did the ice get deposited? One idea is that it is from snowfall (in a different climate), but then it is difficult to explain the presence of the boulders. The other possibility is transport through the shallow subsurface in very thin films of water over many years.
Written by: Alfred McEwen  (22 February 2012)

This is a stereo pair with ESP_025277_2275.
 
Acquisition date
13 January 2012

Local Mars time
14:58

Latitude (centered)
47.067°

Longitude (East)
93.754°

Spacecraft altitude
301.5 km (187.4 miles)

Original image scale range
33.3 cm/pixel (with 1 x 1 binning) so objects ~100 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
26.4°

Phase angle
20.4°

Solar incidence angle
45°, with the Sun about 45° above the horizon

Solar longitude
56.6°, Northern Spring

For non-map projected images
North azimuth:  94°
Sub-solar azimuth:  340.5°
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ANAGLYPHS
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Full resolution JP2 download
Anaglyph details page

DIGITAL TERRAIN MODEL (DTM)
DTM details page

ADDITIONAL INFORMATION
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Black & white is 5 km across; enhanced color about 1 km
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All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
NASA/JPL/University of Arizona

POSTSCRIPT
NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.