The European Space Agency (ESA) has released images of Danielson and Kalocsa craters in the Arabia Terra region of Mars. Danielson is about 60 kilometers in diameter, and Kalocsa is about 33 kilometers across.
The “yardangs” in Danielson crater were formed by a combination of processes. Following the impact, wind blown sediments filled the floor of the crater. At some stage, the material came in contact with water and solidified. The solidified material has since been eroded by more wind blown sand, with the hardest parts now exposed by the sandblasting effect. The direction of the wind can be seen from the parallel lines in the image.
Yardangs are found on Earth, notably in North Africa, Central Asia and Arizona in the United States.
The dark sand dunes extending across the yardang fields appears to be recently formed and composed of volcanic material.