The best example of this variety of layered sedimentary material is found in southern Holden Crater. 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.
North is up.
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.