Indications of Ground Ice in Arcadia Planitia
NASA/JPL/University of Arizona
Indications of Ground Ice in Arcadia Planitia
PSP_004097_2185  Science Theme: Climate Change
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This HiRISE image shows a section of Arcadia Planitia, part of the northern plains of Mars. The plains are extremely smooth at large scale. As seen here, they are knobby and rough up close. The surface texture is likely related to several processes involving subsurface ground ice.

Sublimation (a direct transition from ice to gas, without melting to form liquid water) may be partly responsible; large parts of the Martian mid-latitudes have been mantled with a layer believed to be icy dust. This ice is now being lost in the current dry climate causing the ground to collapse slightly, leaving behind a knobby surface.

Another indication of icy ground is the array of cracks found in several parts of the image. These cracks are due to seasonal thermal contraction of frozen ground, creating stresses that fracture the surface. The cracks can form geometric patterns that interact with topography. Such fracture patterns are one of the most common landform in permafrost on Earth. There are also a few large, enigmatic mounds which may be ice-related; these are currently being studied by the HiRISE team.

Written by: Colin Dundas  (20 June 2007)
 
Acquisition date
11 June 2007

Local Mars time
14:57

Latitude (centered)
38.129°

Longitude (East)
190.206°

Spacecraft altitude
298.6 km (185.6 miles)

Original image scale range
29.9 cm/pixel (with 1 x 1 binning) so objects ~90 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
0.3°

Phase angle
75.3°

Solar incidence angle
75°, with the Sun about 15° above the horizon

Solar longitude
255.6°, Northern Autumn

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  316.9°
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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.