Gullies with Sharp Color Contrasts
NASA/JPL/UArizona
Gullies with Sharp Color Contrasts
PSP_003492_1405  Science Theme: Glacial/Periglacial Processes
This image shows a southern mid-latitude crater: it has bright landslides on its southeast and west walls, some of which have noticeable boulder tracks where boulders rolled down the slopes.

The most noticeable features of this crater are the gullies on the north wall. A couple of small gullies appear to emanate from an overhang. The others originate at or near layers up-slope. The layers are sturdy and resistant from erosion: the layers that appear to be decaying into resolvable boulders, instead of particles easily moved by the wind, are evidence of this.

The color portion of this observation is spectacular. Note the distinct, blue layers lining the south rim of the crater and the white-blue rocks poking through. Wind erosion will likely expose them as time continues.

The top part of the image captures the complex floor of a larger crater upon which the featured crater is superposed. There are a large number of dunes as well as prominent ridges. The color contrast of the gullies to their surroundings is quite distinct. The gullies have blue channels; however, their down-slope debris aprons are redder. This probably indicates a change in particle size, or that the debris aprons have been covered with dust to blend into their surroundings.

Written by: Kelly Kolb  (9 January 2008)

This is a stereo pair with PSP_003215_1405.
 
Acquisition date
25 April 2007

Local Mars time
15:50

Latitude (centered)
-38.976°

Longitude (East)
160.238°

Spacecraft altitude
251.6 km (156.4 miles)

Original image scale range
57.2 cm/pixel (with 2 x 2 binning) so objects ~172 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
28.9°

Phase angle
26.8°

Solar incidence angle
54°, with the Sun about 36° above the horizon

Solar longitude
225.8°, Northern Autumn

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North azimuth:  97°
Sub-solar azimuth:  15.3°
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POSTSCRIPT
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.