25 February 2004
Gullies cut material that mantles the slopes of a deep pit within a crater in Noachis Terra near 50.1°S, 356.4°W in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. Gully channels seem to originate at layer outcrops in the upper walls of the pit. These may have formed by downslope movement of liquid water mixed with debris in the geologically recent martian past. Similar gullies are found throughout much of the martian middle and high latitudes. Sunlight illuminates the scene from the upper left; the picture covers an area 3 km (1.9 mi) wide.