Dunes in Proctor Crater (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)

This image shows the edge of a Dark Dunefield on the Floor of Proctor Crater, an approx. 150 Km diameter Impact Crater located in the Southern Highlands of Mars.

Many smaller and brighter "Bed-Forms", most likely small dunes or Granule Ripples, cover the substrate between the larger Dark Dunes as well as most of the Floor of Proctor Crater. In many locations, large (Erratic) Boulders are seen on the same surfaces as the bright Bed-Forms.
The Dark Dunes stratigraphically overlie the small bright Bed-Forms, indicating that the Dark Dunes formed more recently. However in several areas, the Dark Dunes appear to influence the orientation of the small Bright Dunes, possibly by wind flowing around the larger ones, suggesting that both Dark and Bright Bed-Forms are coeval.