Scalloped Terrain with Layers
Scalloped Terrain with Layers
PSP_002162_2260  Science Theme: Climate Change
This observation shows an area in the northern mid-latitudes of Mars marked by large depressions in the mantle.

The large depressions have scalloped edges and appear to have formed from multiple, smaller scalloped depressions that have coalesced together. The color in this image (see sub image) clearly reveals several layers present within the depressions.

Scalloped pits such as these are typical features of the mid-latitude mantle and are most commonly found at approximately 55 degrees north and south latitude. The presence of scalloped pits has led to hypotheses of the removal of subsurface material, possibly interstitial ice, by sublimation (the process of a material going directly from a solid state to a gaseous state).

Typically, scalloped pits have a steep pole-facing scarp consisting of small pits and fractures and a gentler, smoother, equator-facing slope. This is most likely due to differences in solar heating.

A polygonal pattern of fractures (see subimage), commonly associated with “scalloped terrain,” can be found on the surrounding surface and within the depressions. The fractures indicate that the surface has undergone stress that may have been caused by subsidence, desiccation, or thermal contraction. These polygonal fractures are similar to permafrost (permanently frozen) polygons that form on Earth and are indicative of the presence of ground ice.

Scallop formation may be an ongoing process at the present time.

Written by: Maria Banks  (9 January 2008)

This is a stereo pair with PSP_001331_2260.
Acquisition date
11 January 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
301.2 km (187.2 miles)

Original image scale range
32.2 cm/pixel (with 1 x 1 binning) so objects ~97 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
58°, with the Sun about 32° above the horizon

Solar longitude
165.2°, Northern Summer

For non-map projected images
North azimuth:  98°
Sub-solar azimuth:  340.0°
Black and white
map projected  non-map

IRB color
map projected  non-map

Merged IRB
map projected

Merged RGB
map projected

RGB color
non-map projected

Black and white
map-projected   (1135MB)

IRB color
map-projected   (617MB)

Black and white
map-projected  (493MB)
non-map           (498MB)

IRB color
map projected  (177MB)
non-map           (368MB)

Merged IRB
map projected  (317MB)

Merged RGB
map-projected  (323MB)

RGB color
non map           (353MB)
Map-projected, reduced-resolution
Full resolution JP2 download
Anaglyph details page

B&W label
Color label
Merged IRB label
Merged RGB label
EDR products

IRB: infrared-red-blue
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.