One of the suggested goals for this observation was to investigate the relation of dune material with wall rock as a suspected sand source.
Outcrops of dark material are located upslope of the dune field. Adjacent HiRISE images (e.g, PSP_007218_1660 ) show evidence that the dunes may be locally derived, perhaps being composed of the same material that makes up the wallrock. This area is also being studied to see if any of the dunes are active, in which case changes in the position of dunes and ripples may be seen.
Coprates Chasma is part of the large Valles Marineris canyon, the largest one in the Solar System.
This caption is based on the original science rationale.
Written by: HiRISE Science Team (audio by Tre Gibbs) (30 January 2013)
This is a stereo pair with ESP_025731_1655 .
More info and image formats at http://hirise.lpl.arizona.edu/ESP_025164_1655
Image: NASA/JPL/University of Arizona