Mars Global Surveyor
Mars Orbiter Camera

Alternating Light- and Dark-toned Layers in Holden Crater

MGS MOC Release No. MOC2-262, 4 December 2000


(A) Holden Crater Context

Image source: Viking Orbiter Mosaic, U.S. Geological Survey

(B) Layers in Holden Crater

"Colorized" subframe of MOC image M03-02733

While many of the layered outcrops in craters and chasms on Mars are seen as stair-stepped series of cliffs and benches composed of similar materials with similar thicknesses (e.g., as in the crater at 8°N, 7°W and in Candor Chasma), other layer outcrops are expressed on relatively smooth, rounded slopes as alternating light and dark bands. The best example of this variety of layered sedimentary material is found in southern Holden Crater. Holden is located at 26.5°S, 33.9°W, and has a diameter of 141 km (88 mi). The context in Picture A, above, shows that a valley, Uzboi Vallis, enters the crater on its southwestern side. Not too far from where Uzboi Vallis meets Holden Crater, rounded slopes and buttes consisting of alternating light and dark bands are seen. The origin of these layers is not known, but like those found in other craters on Mars, they might have resulted from deposition of sediment in a lake that would have occupied Holden Crater. Alternatively, these are materials deposited by falling out of the air, the same way that volcanic ash is deposited on Earth. The Viking mosaic (Picture A) images are illuminated by sunlight from the upper right. The MOC image (Picture B) is illuminated from the upper left. North is up.

Additional Image Viewing Options:

(A) Holden Crater Context:

(B) Layers in Holden Crater:

A brief description of how the color was generated:

The MOC narrow angle camera only takes grayscale (black and white) pictures. To create the color versions seen here, we have taken much lower resolution red and blue images acquired by the MOC's wide angle cameras, and by the Viking Orbiter cameras in the 1970s, synthesized a green image by averaging red and blue, and created a palette of colors that represent the range of colors on Mars. We then use a relationship that correlates color and brightness to assign a color to each gray level. This is only a crude approximation of martian color and should only be considered representative of Mars. It is likely the colors would not look like this to a human observer at 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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