Slope Streaks in Acheron Fossae
NASA/JPL-Caltech/UArizona
Slope Streaks in Acheron Fossae
PSP_001656_2175  Science Theme: Mass Wasting Processes
This observation shows a portion of the wall (light-toned material) and floor of a trough in the Acheron Fossae region of Mars.

Many dark and light-toned slope streaks are visible on the wall of the trough surrounded by dunes. Slope streak formation is among the few known processes currently active on Mars. While the mechanism of formation and triggering is debated, they are most commonly believed to form by downslope movement of extremely dry sand or very fine-grained dust in an almost fluidlike manner (analogous to a terrestrial snow avalanche) exposing darker underlying material.

Some of the slope streaks show evidence that downslope movement is being diverted around obstacles, such as large boulders, and a few appear to originate at boulders or clumps of rocky material. These slope streaks, as well as others on the planet, do not have deposits of displaced material at their downslope ends. The darkest slope streaks are youngest and can be seen to cross cut and lie on top of the older and lighter-toned streaks. The lighter-toned streaks are believed to be dark streaks that are lightening with time as new dust is deposited on their surface.



Written by: Maria Banks  (7 February 2007)

This is a stereo pair with PSP_002632_2175.
 
Acquisition date
03 December 2006

Local Mars time
15:25

Latitude (centered)
37.317°

Longitude (East)
229.117°

Spacecraft altitude
290.3 km (180.4 miles)

Original image scale range
58.1 cm/pixel (with 2 x 2 binning) so objects ~174 cm across are resolved

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50 cm/pixel and North is up

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Equirectangular

Emission angle
0.9°

Phase angle
51.8°

Solar incidence angle
51°, with the Sun about 39° above the horizon

Solar longitude
144.7°, Northern Summer

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North azimuth:  97°
Sub-solar azimuth:  353.6°
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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.