Slope Streaks in Terra Sabaea
NASA/JPL/UArizona
Slope Streaks in Terra Sabaea
PSP_001808_1875  Science Theme: Mass Wasting Processes
This observation shows the rim of a crater in the region of Terra Sabaea in the northern hemisphere of Mars.

The subimage is a close-up view of the crater rim revealing dark and light-toned slope streaks. Slope streak formation is among the few known processes currently active on Mars. While their 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.

Other ideas include the triggering of slope streak formation by possible concentrations of near-surface ice or scouring of the surface by running water from aquifers intercepting slope faces, spring discharge (perhaps brines), and/or hydrothermal activity.

Several of the slope streaks in this subimage, particularly the three longest darker streaks, show evidence that downslope movement is being diverted around obstacles such as large boulders. Several streaks also appear to originate at boulders or clumps of rocky material.

In general, the slope streaks do not have large deposits of displaced material at their downslope ends and do not run out onto the crater floor suggesting that they have little reserve kinetic energy. The darkest slope streaks are youngest and can be seen to cross cut and superpose older and lighter-toned streaks. The lighter-toned streaks are believed to be dark streaks that have lightened with time as new dust is deposited on their surface.


Written by: Maria Banks  (24 January 2007)
 
Acquisition date
15 December 2006

Local Mars time
15:36

Latitude (centered)
7.411°

Longitude (East)
46.994°

Spacecraft altitude
270.7 km (168.2 miles)

Original image scale range
54.4 cm/pixel (with 2 x 2 binning) so objects ~163 cm across are resolved

Map projected scale
50 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
7.4°

Phase angle
46.4°

Solar incidence angle
53°, with the Sun about 37° above the horizon

Solar longitude
150.7°, Northern Summer

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  16.2°
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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.