Dark Spot Near Olmpus Mons Volcano (natural colors; credits: Lunexit)

This image covers a relatively dark-toned patch of ground West of the Olympus Mons volcano. This spot is one of several "Dark Areas" in this Region of Mars.
These Dark Spots are distinctive because much of the surrounding area appears to be covered by light-toned dust.

In pre-HiRISE images, the origin of this Dark Spot was ambiguous. This HiRISE image reveals that the dark color is likely the result of accumulations of Basaltic Sand (smooth, brown-colored material in this natural color view) on top of otherwise relatively dust-free bedrock.
Evidence of layering is also visible within the dark area. There are alternating bands of lighter- and darker-toned material, consistent with alternating layers of bedrock. These alternating bands are not apparent outside of the Dark Area. This may mean that alternating layers of bedrock only occur within the dark area, or that these bedrock layers occur throughout the region but are covered and obscured by light-toned dust outside of the Dark Area.