Dunes with Unusual Gully
Dunes with Unusual Gully
PSP_006648_1300  Science Theme: Aeolian Processes
Seen here is the eastern edge of a dune field in a large, degraded crater in the southern hemisphere. Similar to other dunes on Mars, these dunes are dark-toned and contain gullies.

Gullies are features found on slopes and dunes in the mid-latitudes of both hemispheres. Both slope and dune gullies were initially suggested to be a result of liquid water from the surface or subsurface. Slope and dune gullies usually have different morphologies: dune gullies are more linear and have levees bordering their channels. They typically have no distinguishable, or very small, alcove and debris aprons. Slope gullies, on the other hand, often have deeply incised alcoves and channels that exhibit fluvial characteristics such as streamlined islands.

What is highly unusual about this dune field is that one of its gullies has the morphology of a slope gully (approximately 3 kilometers across)! This dune gully has a very incised alcove, what appears to be streamlined islands on the channel floor, and a large, feathery debris apron.

Written by: Kelly Kolb  (13 February 2008)
Acquisition date
27 December 2007

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
249.7 km (155.2 miles)

Original image scale range
25.0 cm/pixel (with 1 x 1 binning) so objects ~75 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection

Emission angle

Phase angle

Solar incidence angle
64°, with the Sun about 26° above the horizon

Solar longitude
8.8°, Northern Spring

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  49.3°
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   (921MB)

IRB color
map-projected   (419MB)

Black and white
map-projected  (456MB)
non-map           (530MB)

IRB color
map projected  (174MB)
non-map           (418MB)

Merged IRB
map projected  (196MB)

Merged RGB
map-projected  (201MB)

RGB color
non map           (405MB)
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

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NASA/JPL/University of Arizona

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.