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View Diary: Getting to Know Your Solar System (11): Mars (Vol. 1) (38 comments)

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  •  For sheer beauty, I quite like this one (8+ / 0-)

    In the Arabia Terra region. The contrast is created by layers of ancient, light colored material, and new, dark material, as well as the varying elevation of the layers.

    Mars' Arabia Terra region
    NASA/JPL/Malin Space Science Systems (2006)
    The very ancient and the modern come together in this small, approximately 3 km by 3 km (1.9 mi by 1.9 mi) area on the floor of an unnamed impact crater in western Arabia Terra.

    Old are the light-toned, layered mounds scattered across the image. The layers form stair-steps leading to the top of each mound. In most cases, the 'steps' are not clean, but are instead covered with debris eroded from the next layer, or step, above. The mounds are remnants of layered rock that once covered the entire scene. They were deposited as sediment in the large, unnamed crater in which these landforms occur. Their regular thickness and repeated character suggest that episodic, or perhaps cyclic, processes brought sediment to the crater floor. If the crater contained water at the time the sediments were deposited, then they represent lakebed materials. The processes that (a) brought sediment to this site, (b) cemented the sediment to form rock, and (c) eroded the sediment to form the mounds we see today, all occurred at some time in the distant past.

    New are the dark-toned sand dunes and intermediate-toned ripples. The dark dunes were formed of sand that in relatively recent times has been blown by wind from the northeast (upper right) toward the southwest (lower left). The dunes have slowly encroached upon the older, light-toned, layered mounds. Surrounding each mound is a suite of intermediate-toned ripples. These are large ripples, relative to counterparts on Earth, and are most likely made up of grains somewhat coarser than sand, typically of several millimeters in size. The ripples form a pattern that is generally radial to each mound, indicating that they formed in winds that interacted with these topographic obstacles. The dark dunes are generally younger than the ripples, as dark sand has encroached upon and over-ridden some of the ripples.

    This image is one of the favorites of the MOC operations team at Malin Space Science Systems, because it is not only pretty, it also emphasizes aspects of both the ancient and modern sedimentary processes and materials on Mars. Sediments, sedimentary rocks, and the environments in which they were deposited have been a key theme of the MOC science investigation from the beginning, more than 20 years ago, when MOC was selected by NASA to be built and sent to Mars.

    Fry, don't be a hero! It's not covered by our health plan!

    by elfling on Sun Mar 18, 2012 at 10:35:43 PM PDT

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