In this VIS image, taken by the NASA - Mars Odyssey Orbiter on April, 9th, 2014, and during its 54.643rd orbit around the Red Planet, we can see very Dark Dunes (as a matter of fact, it is a quite large Dunefield) which are (is) located in a Surface Depression bounded (---> surrounded) by Water Ice.
The North Polar Water Ice is the bright Material clearly visible both at the top and bottom parts of this frame. On the other hand, the pink/reddish nuances that can be seen on the (otherwise completely white, with pale blue reflections) Water Ice are, most likely, the final result of the falling on the Ground of a relatively high quantity of Dust, that was previously suspended in the lower Strata of the Martian Atmosphere.
Latitude (centered): 83,1846° North
Longitude (centered): 115,7100° East
This image (which is a crop taken from an Original Mars Odyssey Orbiter b/w and Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 18489) has been additionally processed, magnified to aid the visibility of the details, contrast enhanced and sharpened, Gamma corrected and then colorized in Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.