Northern Hemisphere gullies on west-facing crater slope

Like many midlatitude Martian craters, this impact crater has gullies along its walls that are composed of alcoves, channels, and debris aprons. The origins of these gullies have been the subject of much debate; they could have been formed by flowing water, liquid carbon dioxide, or dry granular flows. The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took the image on April 13, 2010.