6 April 2004
This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies in the wall of a large impact crater in Newton Basin near 41.9°S, 158.1°W. Such gullies may have formed by downslope movement of wet debris--i.e., water. Unfortunately, because the responsible fluid (if there was one) is no longer present today, only the geomorphology of the channels and debris aprons can be used to deduce that water might have been involved. The image covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left.