Scarps and Pits
Scarps and Pits
ESP_078316_2260  Science Theme: Glacial/Periglacial Processes
Some areas of Mars show a kind of selective erosion. In this image, an overlapping pit formed between one level of the surface and another. One idea is that the ground once contained significant amounts of ice in layers a few meters thick that have evaporated. Without the ice, the ground surface subsides and collapses down to a new and somewhat level surface.

Alternatively, the terrain may have been ice rich. The loss of this cement-like ice then left the surface unable to resist erosion from the wind, and allowed the surface to gradually deflate down to a new more resistant level. Either way, the current curved scarps, a few meters high between these layers may, suggest that the process is ongoing.

Written by: Mike Mellon  (18 July 2023)

Acquisition date
11 April 2023

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
301.3 km (187.2 miles)

Original image scale range
60.3 cm/pixel (with 2 x 2 binning) so objects ~181 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

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

Solar longitude
49.6°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  344.5°
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Black and white
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non-map           (198MB)

IRB color
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Black & white is 5 km across; enhanced color about 1 km
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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.