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Mars Global Surveyor
Mars Orbiter Camera

Mars Shoreline Tests: Massifs in the Cydonia Region

MGS MOC Release No. MOC2-182, 1 October 1999


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Mars Global Surveyor's (MGS) Mars Orbiter Camera (MOC) took the above picture (second of the two) of some massifs and mesas in the Cydonia region of Mars in early September 1998. The purpose of this image--number SPO2-532/04---was to test the hypothesis that the martian northern plains were once the site of an ocean or large sea. According to this hypthesis, and according to peer-reviewed and published maps, each one of the mesas and massifs in the two pictures above should have shorelines around their margins. The hypothesis holds that these were once islands and that waves would lap--and sometimes crash--against these landforms, rip off huge chuncks of rock, and create steep cliffs and stair-stepped terraces in the rock.

The first picture above shows the regional context of the MOC high resolution view in Cydonia. The context picture, from Viking orbiter image 227S11, is illuminated from the right. The second picture above is a figure that shows the full SPO2-532/04 MOC image and two expanded views of portions of this image. Mesas are flat-topped uplands, and massifs are the more triangular, massive peaks. If an ocean had been present in this region, terraces that indicate erosion or "bathtub rings" of salt or carbonate deposits left by the retreat of this ocean as it dried up might be found around each mesa and massif. No such features are found, nor is it at all obvious why these mesas and massifs were portrayed in previously published figures as having shorelines around them. The MOC image is illuminated from the left.

For a higher-resolution view of the context image (495 Kbyte), CLICK HERE.

For a higher-resolution view of the narrow angle camera figure (890 Kbyte), CLICK HERE.

For additional MOC image tests of proposed martian shorelines, see the following:

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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