Figure: Layered rock deep in martian crust

Mars Orbiter Camera (MOC) High Resolution Images:
Western Tithonium Chasma/Ius Chasma, Valles Marineris

On October 3, 1997, the MOC acquired this image of the western Tithonium Chasma/Ius Chasma portion of the Valles Marineris, centered at 6.6 ^oS, 90.4 ^oW, at 1:16 PM PDT. Although the lighting beneath the spacecraft was very poor, the camera was canted towards the sun, and the illumination was equivalent to roughly 5 PM local time (the sun was about 17^o above the horizon). In the image, the canyon floors are mostly shadowed, but steep slopes in the area are exquisitely highlighted.

Most remarkable about the MOC image is the discovery of light and dark layers in the rock outcrops of the canyon walls. In the notable, triangular mountain face (at the top of the image), some 80 layers, typically alternating in brightness and varying in thickness from 5 to 50 meters are clearly visible. This shear mountain cliff, over 1000 m tall, is only one of several outcrops that, together, indicate layering almost the entire depth of the canyon.

This type of bedrock layering has never been seen before in Valles Marineris. It calls into question common views about the upper crust of Mars, for example, that there is a deep layer of rubble underlying most of the martian surface, and argues for a much more complex early history for the planet.

Credit: Malin Space Science Systems/NASA

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, CA. 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, CA and Denver, CO.

http://mars.jpl.nasa.gov/mgs/gallery/20061121a.html

and

http://www.msss.com/mars_images/moc/11_10_97_release/1303/