Gullies in a Crater Wall
Gullies in a Crater Wall
PSP_007977_2385  Science Theme: Glacial/Periglacial Processes
This image displays several nice examples (see the subimage) of classical "alcove-channel-apron" gullies in a 10 kilometer (about 6 miles) diameter crater located in Mars' Northern mid-latitudes.

The alcove is the cupped area near the crater rim where rock has eroded and been transported through the gully. The channel is the narrow route through which all of the alcove material is transported. That material is then deposited into the fan-shaped apron near the crater floor.

In 2006 the Mars Orbiter Camera (MOC) found evidence of new changes to the deposits in some Martian gullies. The formation mechanism for gullies on Mars is therefore an important topic of current debate: while gullies can form in the presence of water, there are also dry formation mechanisms that can produce very similar features. Scientists study gullies in part to try to help clarify the question of the history of water on Mars.

Written by: Nicole Baugh  (9 June 2008)

This is a stereo pair with PSP_008043_2385.
Acquisition date
09 April 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
307.2 km (190.9 miles)

Original image scale range
30.8 cm/pixel (with 1 x 1 binning) so objects ~92 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
48°, with the Sun about 42° above the horizon

Solar longitude
56.2°, Northern Spring

For non-map projected images
North azimuth:  98°
Sub-solar azimuth:  332.5°
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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’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.