From NASA

Though Mars is the Red Planet, false-color images can help us learn about its weather and geology. This image shows a variety of wind-related features on the Red Planet near the center of Gamboa Crater. Larger sand dunes form sinuous crests and individual domes.

There are tiny ripples on the tops of the dunes, only several feet from crest-to-crest. These merge into larger mega-ripples about 30 feet apartthat radiate outward from the dunes. The larger, brighter formations that are roughly parallel are called ?Transverse Aeolian Ridges? (TAR). These TAR are covered with very coarse sand.

The mega-ripples appear blue-green on one side of an enhanced color cutout while the TAR appear brighter blue on the other. This could be because the TAR are actively moving under the force of the wind, clearing away darker dust and making them brighter. All…