Mars Global Surveyor
Mars Orbiter Camera
Unconformity in Gale Crater Mound
MGS MOC Release No. MOC2-265G, 4 December 2000
A hint as to the complexity of the history recorded in the rocks
of the Gale Crate central mound is shown by the partial emergence
of a buried crater from beneath a light-toned, massive (i.e.,
not layered) rock unit. The massive light-toned rock covers the upper
left quarter of the image on the left, which is a subframe of
Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image M03-01521.
The picture on the right is a colored map showing the different
layered and massive rock units identified in the Gale Crater mound;
the white box indicates the location of the picture on the left.
The crater seen here formed in a previously-existing layered rock
unit that was later buried by the light-toned massive unit seen
at the upper left. This means that there is a gap in the geologic
record---some of the history of this location is missing---because
the gray-toned rock into which the crater formed was exposed to the
atmosphere and eroded and hit by meteorites (to form craters) before
the light-toned massive material was deposited and the record resumed.
In geologic terms, this kind of relationship is called an
unconformity. Refer to
"Oblique view of Gale Crater Mound," MOC2-265E, December 4, 2000 to see the location of the color map relative to the entire
mound. For additional information about Gale Crater, see
Sediment History Preserved in Gale Crater Central Mound, MOC2-260, 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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