Defrosted Margin of the North Polar Erg (natural colors; credits: Lunexit)

This image shows a traverse across a section of the North Polar Erg, a vast Sea of Sand that surrounds the Polar Cap.

The source of the dunes may be from the eroding North Polar Layered Deposits. Wind, acting on this mixture of sand, dust and ice, has formed several dune types on top of bright megaripples and polygons. A dark mantle of sand lies beyond the dunes.

The central part of the field contains transverse dunes with the dominant wind direction coming from the North/West-West. The outer edges of the Dunefield transition into "Star Dunes" (with multiple arms) and "Barchanoid Dunes" (crescent-like shape). The Star Dunes indicate a multidirectional wind regime or a change in wind direction over the Dunefield’s evolution.
The dunes are somewhat confined to their location and may have taken hundreds of years to form.