Large Southern Hemisphere Gully
Large Southern Hemisphere Gully
PSP_007126_1210  Science Theme: Aeolian Processes
This image shows a large gully in the wall of a crater in the southern hemisphere. Such gullies are among the most recent landforms on Mars, and were probably carved by liquid water.

The source of the water is still unknown; it could have been groundwater from a shallow aquifer or melted snow or ground ice from a different climate.

This gully is not particularly fresh, but it is among the largest observed; several sub-channels merge in the alcove on the upper slope, in the north part of the image. Numerous faint troughs and lineations are visible downslope, likely indicating old channels that have been buried or reworked. The upper alcove exposes a dense cluster of boulders not seen on the adjacent slope. This could indicate that smaller material has been removed by the gullies, exposing the boulders without transporting them far.

Written by: Colin Dundas  (16 April 2008)
Acquisition date
02 February 2008

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
253.3 km (157.4 miles)

Original image scale range
50.7 cm/pixel (with 2 x 2 binning) so objects ~152 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
78°, with the Sun about 12° above the horizon

Solar longitude
26.4°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  51.7°
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Merged IRB
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IRB color
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Black and white
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non-map           (148MB)

IRB color
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non-map           (130MB)

Merged IRB
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Merged RGB
map-projected  (226MB)

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

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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.