This color HiRISE view shows a pitted, blocky surface, but also more unusually, it has contorted, irregular features. Although there are impact craters in this area, some of the features (like in the lower center of the cutout) are too irregular to be relic impact craters or river channels. One possibility is that sedimentary layers have been warped from below to create these patterns. The freezing and thawing of subsurface ice is a mechanism that could have caused this. Acidalia Planitia is part of the northern plains of Mars, at a latitude of 44 degrees north.

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Photo credit: © NASA/piemags / Alamy / Afripics
License: Licensed
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Keywords: ., mars, orbiter, reconnaissance