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Cool image time! The picture to the right, cropped to post here, was taken on November 30, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a variety of ridges in a region of Mars called Arabia Terra, which is also the largest transition zone between the Martian southern cratered highlands and the northern lowland plains.
While this picture illustrates some nice geological facts about Mars (see below), I post it simply because of the dramatic sharpness of the ridge on top of the mesa, which I guess is several hundred feet high, but only a few feet across, at most, at its peak. A hike along this ridgeline would be a truly thrilling experience, one that the future human settlers on Mars will almost certainly find irresistible. Put this location on your planned tourist maps of Mars. It will likely be an oft-visited site.
Now for the geology. The black dot just south of 30 degree north latitude marks the location of this mesa. As it is in the dry equatorial regions, it is thus no surprise that the terrain in this picture appears bone dry.
However, the parallel small ridges to the south of the mesa, that are also aligned with the ridge, suggest to my eye the possibility of past glacial activity. Once, ice might have slid across this ground, leaving behind scour marks and those parallel ridges.
Or not. I am guessing. The parallel ridges could also be the result of wind erosion caused by north-south prevailing winds. These ridges might also be volcanic dikes, where lava pushes up through cracks, and remains long after the surrounding terrain erodes away because the lava is harder and more resistant to erosion.
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