Icy Erosion
Icy Erosion
ESP_042886_1480  Science Theme: Landscape Evolution
This image shows an interesting collection of kilometer-scale craters with flat and smooth floors. The craters themselves may be the result of secondary impacts, craters caused by debris from a distant larger impact. Since then, the surface has been significantly modified and reworked, muting the craters and flattening their floors.

Presently, there are a few sand dunes and a broad overlay of a dusty soil mantle. This soil mantle occurs over much of the middle latitudes of Mars. Here, as elsewhere, the mantle covers these craters, but a closer inspection reveals that its smooth texture becomes significantly pitted and bumpy on the pole facing slopes of each crater interior wall.

It has been hypothesized that this pitting of the mantle is the result of the evaporation of shallow ice. As subsurface ice is lost, the removal of this bonding ice cement allows soil grains to be eroded by the wind. Then the resulting deflation of the soil forms the observed pitted textures. Alternatively, the loss of relatively pure underground ice deposits would cause a reduction of the surface soil and collapse to form the same textures.

Written by: Mike Mellon (audio: Tre Gibbs)  (23 December 2015)
Acquisition date
20 September 2015

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
254.5 km (158.2 miles)

Original image scale range
50.9 cm/pixel (with 2 x 2 binning) so objects ~153 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
65°, with the Sun about 25° above the horizon

Solar longitude
43.9°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  48.8°
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IRB color
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Black and white
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non-map           (80MB)

IRB color
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non-map           (80MB)

Merged IRB
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Merged RGB
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RGB color
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B&W label
Color label
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RGB: red-green-blue
About color products (PDF)

Black & white is 5 km across; enhanced color about 1 km
For scale, use JPEG/JP2 black & white map-projected images

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’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.