Sand Sources Near Athabasca Valles
NASA/JPL/UArizona
Sand Sources Near Athabasca Valles
ESP_038224_1890  Science Theme: Fluvial Processes
This image shows a small channel cutting into young volcanic lavas in a region where massive catastrophic flooding took place in the relatively recent past. The Athabasca Valles region includes a vast lava flow, thought to be the youngest on Mars, with even younger outflow channels that were carved by running water. The source of the water is believed to be the Cerberus Fossae valleys to the north, which may have penetrated to an over-pressurized aquifer in the subsurface.

Nowadays, erosion by gravity, wind, and frost gradually wears down the rims of the outflow channels. In this scene, we see dark materials along the channel rim that were probably exposed by this erosion. The dark materials are less red than the surrounding surface and so they appear blue in this enhanced color picture. Viewed close up, the dark materials show ripples that suggest they are made up of mobile sand. It is possible that this sand originated elsewhere and simply collected where we see it today, but the fact that sand is not found elsewhere in the scene suggest to us that it is eroding out of the volcanic layers at the retreating rim of the channel.

Sand sources are important because mobile sand grains have only a limited lifetime, wearing down and chipping apart each time they impact the surface. Erosion of the volcanic materials in this region may provide sands to replace those that are destroyed. Few such sand sources have so far been identified on Mars.

Written by: Paul Geissler  (29 October 2014)
 
Acquisition date
21 September 2014

Local Mars time
15:47

Latitude (centered)
8.926°

Longitude (East)
155.992°

Spacecraft altitude
276.0 km (171.5 miles)

Original image scale range
27.8 cm/pixel (with 1 x 1 binning) so objects ~83 cm across are resolved

Map projected scale
25 cm/pixel and North is up

Map projection
Equirectangular

Emission angle
6.7°

Phase angle
52.6°

Solar incidence angle
59°, with the Sun about 31° above the horizon

Solar longitude
200.5°, Northern Autumn

For non-map projected images
North azimuth:  97°
Sub-solar azimuth:  350.3°
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Black & white is 5 km across; enhanced color about 1 km
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All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:
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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.