Gully Alcoves at the Very Top of a Slope
NASA/JPL-Caltech/UArizona
Gully Alcoves at the Very Top of a Slope
PSP_007143_1370  Science Theme: Fluvial Processes
Several characteristics of crater wall gullies are visible in this image that provide possible insight into the formation mechanisms of gullies on Mars.

Gullies near the top (north) end of the image are deeper and originate in alcoves near the rim of the crater. Gullies near the middle of the image are shallow and contain a more complex array of small channels. These smaller gullies initiate from a uniform elevation within the crater wall rather than at the crater rim. This suggests that the materials which flow down the crater slopes to form the gullies originates at a specific layer exposed in the crater wall.

The undulating pattern of ridges on the crater floor (left side of the image) appear similar to features interpreted as elsewhere on Mars that involve ice-rich materials.


Written by: Kelly Kolb  (16 July 2008)
 
Acquisition date
04 February 2008

Local Mars time
14:51

Latitude (centered)
-42.837°

Longitude (East)
198.216°

Spacecraft altitude
252.8 km (157.1 miles)

Original image scale range
25.3 cm/pixel (with 1 x 1 binning) so objects ~76 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
1.8°

Phase angle
68.1°

Solar incidence angle
67°, with the Sun about 23° above the horizon

Solar longitude
27.0°, Northern Spring

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North azimuth:  97°
Sub-solar azimuth:  48.6°
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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.