It looks like a filmmaker's apocalyptic vision of Earth following a devastating natural disaster. But this colossal ice formation is actually a portion of the wall terraces of a huge crater on Mars.
Approximately 37 miles in diameter, a section of the Mojave Crater in the planet's Xanthe Terra region has been digitally mapped by Nasa scientists. The result is this digital terrain model that was generated from a stereo pair of images and offers a synthesized, oblique view of a 2.5-mile portion of the crater's wall terraces.
The sheer depth of the crater - about 1.6 miles - demonstrates that Mojave has experienced little infilling or erosion. The result offers scientists a tantalising glimpse of what a very large complex crater looks like on Mars because it remains so fresh while most others - especially this size - have been affected by erosion, sedimentary infilling and overprinting by other geologic processes.
Such a fresh crater provides an insight into the impact process. 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.
The portion of the Mojave Crater's north-western edge shown here spans 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 ten million years, very young for a crater of this size.
The fans and channels hint that impacts such as Mojave's may have unleashed water or water-ice from the subsurface to flow across the surface and, perhaps, condense as rain or snow for a brief period of Martian time.
This further suggests that early climate on Mars could have been heavily influenced by the intense bombardment about 3.9billion years ago when impacts creating craters Mojave's size and far larger were more common.
adapted from: http://english.kompas.com/read/2010/03/23/06011770/Mars.as.Youve.Never.Seen.It.before
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