Though the surface of the Red Planet has not hosted earthquakes or volcanic eruptions as has the surface of Earth, winds and seasonal changes shape and reshape the Martian landscape.
The above mounds on what appears to be a hard, bumpy terrain of permafrost are called barchan dunes. Barchans generally form where there’s a supply of sand and a prevailing wind.
In this photo, a prevailing wind blows sand into these 100-meter wide mounds to create the structures. The “arms” or “horns” of the dunes point in the downwind direction, indicating that the prevailing winds blow toward the northwest.
Typically, the leading/upwind edge of the dune is gently sloped and more rounded.
Scientists plan to use repeat imaging of this dune field to determine if the dunes are presently moving.
The photo was taken using the High-Resolution Imaging Science Experiment (HiRISE) camera on board NASA’s Mars Reconnaissance Orbiter (MRO).
Sources: Discovery News July 17, 2012 HiRISE July 11, 2012
Photos credit NASA/JPL/University of Arizona