This mound on Mars in the center of this image, appears to have blocked the path of the dunes as they marched south across the scene.
Many of these transverse dunes in this Mars Reconnaissance Orbiter (MRO) image, have slipfaces that face south, although in some cases, it’s hard to tell for certain. Smaller dunes run perpendicular to some of the larger-scale dunes, probably indicating a shift in wind directions in this area.
Although it might be hard to tell, this group of dunes is very near the central pit of a 35-kilometer-wide impact crater. Data from other instruments indicate the presence of clay-like materials in the rock exposed in the central pit.
This image was acquired by the High Resolution Imaging Science Experiment (HiRISE) instrument aboard MRO on April 27, 2009, at 15:16 local Mars time. It is a stereo pair with image ESP_013319_1685.
Image Credit: NASA/JPL/University of Arizona
Caption: Nicole Baugh