Thursday, February 18, 2010

NASA MARS Rovers: Mojave Crater


Mars Rover Picture of Mojave Crater

A digital terrain model generated from a stereo pair of images provides this synthesized, oblique view of a portion of the wall terraces of Mojave Crater in the Xanthe Terra region of Mars.
This view, in which the vertical dimension is exaggerated three-fold compared with horizontal dimensions, shows the ponding of material backed up behind massive wall-terrace blocks of bedrock.
Hundreds of impact craters on Mars have similarly ponded features with pitted surfaces. These "pitted ponds" are thought to result when material melted by the crater-causing impacts is captured behind the wall terraces.

Mojave Crater is approximately 60 kilometers (37 miles) in diameter, centered at 327.0 degrees east longitude, 7.5 degrees north latitude. The portion of its northwestern edge shown here spans about 3.5 kilometers (about 2.5 miles) in width halfway between the bottom and top of the image. The view is toward the north.

Mojave is one of the freshest large craters on Mars. A survey of its features indicates very few overprinting craters on them, and an analysis of that infrequency suggests the crater may be as young as about 10 million years, very young for a crater of this size. The depth of the crater -- about 2.6 kilometers (1.6 miles) -- also demonstrates that Mojave has experienced little infilling or erosion.

Mojave gives us a glimpse of what a very large complex crater looks like on Mars. In a sense, it is a "Rosetta Stone" of craters, given that it's so fresh and most others -- especially this size -- have been affected by erosion, sedimentary infilling and overprinting by other geologic processes. Such fresh craters give insight into the impact process: ejecta, melt-generation, deposition, etc.

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