Mars Global Surveyor
Mars Orbiter Camera

Martian Gullies

MGS MOC Release No. MOC2-1163, 25 July 2005

NASA/JPL/Malin Space Science Systems

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a gullied crater wall in the Terra Sirenum region of Mars. The fluids that formed the gully channels and deposited debris in aprons at the base of the crater wall may have percolated through layers in the layered bedrock exposed in the crater wall. As fluid seeped out of the ground, it undermined overlying layers of rock, and caused the formation of several compex alcoves, higher in the crater wall. The formation of alcoves requires the undermining and collapse of layered material at a point where the channel begins; this is a key observation supporting the hypothesis that martian gullies require groundwater, not snowmelt or other exotic processes or fluids, to form.
Location near: 37.3°S, 153.2°W
Image width: ~3 km (~1.9 mi)
Illumination from: upper left
Season: Southern Spring

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Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, California. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, California and Denver, Colorado.

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