Curving Ridges in Aeolis Planum

Multiple processes, which may have occurred billions of years apart, are reflected in this HiRISE image of Aeolis Planum. Cutting across the scene are curvilinear ridges. These likely represent ancient, meandering river channels that flowed across the surface and buried themselves over time. The channels have subsequently been exposed to the surface by the wind, forming the cross-cutting ridges. Approximately north-south across the image are a series of linear ridges called "yardangs," which are streamlined landforms that also form due to wind-driven erosion. The orientation of the yardangs reflects the prevailing wind direction when they formed. Both sets of ridges emerged from the preferential removal of softer bedrock by the wind. https://photojournal.jpl.nasa.gov/catalog/PIA25989