Mars Global Surveyor
Mars Orbiter Camera
Layered and Massive Units, Candor Mensa
MGS MOC Release No. MOC2-265D, 4 December 2000
Not all martian sedimentary rocks are expressed as stacks of thin,
repeated beds, all of similar thickness, like those in west Candor Chasma or western
Arabia Terra; some of them consist of a single, thick layer with
very little clear evidence for bedding (geologists use the term
massive to describe such layers). On Mars, massive units are
typically found above layered units, indicating that they are younger
and that the depositional environment changed over time, from one that
was changing in a repeated, episodic fashion, to one in which little
change occurred over some period of time. This image, on the north
slope of Candor Mensa in the Valles Marineris, shows a transition from
layered lower units to a massive upper unit. The surface slopes
down from the top to the bottom of the image, sunlight illuminates the
scene from the lower right. The picture is a subframe of Mars Global
Surveyor (MGS) Mars Orbiter Camera (MOC) image M10-02361, obtained in
December 1999. The north slope of Candor Mensa can be seen in a
Viking orbiter image mosaic that is part of an accompanying release,
"Light-toned Layered Outcrops in Valles
Marineris Walls," MOC2-263, December 4, 2000.
Image Credit: NASA/JPL/Malin Space Science Systems
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.
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