Today's Image of Mars comes from HiRISE shows a dune that lies close to an impact crater. This dune is special because it preserves the original bedform shapes of the sand dune, but lies over top of a previously eroded surface of sedimentary rock.
Scientists are still attempting to find a dune that has been directly impacted by an asteroid, in hopes that it will help them better understand dunes and how they are formed.
Click on the image to view it in high resolution. [See the original HiRISE caption for the image]