10 October 2004
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows ripples on the surface of a dune in a crater west of Sinus Meridiani near 2.5°N, 9.3°W. Most martian dune surfaces do not show ripples at the scale of MOC images---a higher resolution (better than 15 cm/pixel) view would be needed. These ripples are probably not typical sand ripples; they may be coarser-grained granule ripples (usually made up, in part, of grains 1-4 millimeters in size). The light-toned features in the image are wind-eroded outcrops of sedimentary rock. The image covers an area about 1.5 km (~0.9 mi) wide. Sunlight illuminates the scene from the upper left.