Mars Global Surveyor
Mars Orbiter Camera
Mid-Latitude Sedimentary Rock: Spallanzani Crater
MGS MOC Release No. MOC2-269, 31 January 2001
Although most of the best examples of
layered sedimentary rock
seen on Mars are found at equatorial and sub-tropical
latitudes, a few locations seen at mid- and high-latitudes suggest that
layered rocks are probably more common than we can actually see from
orbit. One extremely good
example of these "atypical" layered rock exposures is found
in the 72 km-diameter (45 miles) crater, Spallanzani (58.4°S, 273.5°W).
Located southeast of Hellas Planitia, the crater is named for
the 18th Century Italian biologist, Lazzaro Spallanzani (1729-1799).
Picture A presents a composite of the best
Viking orbiter image (VO2-504B55) of the region with 4 pictures obtained
June 1999 through January 2001 by the Mars Global Surveyor Mars Orbiter
Camera (MOC).
Each MOC narrow angle image is 3 km across. Taken in the
MOC's "survey mode," all four images were acquired at roughly 12
meters (39 ft) per pixel.
Picture B zooms-in on the portion of the composite image that includes
the 4 MOC images (the 100%-size view is 20 m (66 ft) per pixel).
Other craters in the region near Spallanzani show features--at Viking
Orbiter scale--that are reminiscent of
the layering seen in Spallanzani. Exactly what these layers are made of
and how they came to be where we see them today are mysteries, but it
is possible that they are similar to the materials seen in the
many craters and chasms of the equatorial latitudes on Mars.
Images 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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