Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on February 4, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the terminating cliffs of the north pole ice cap of Mars, dubbed Rupes Tenius on this side of the icecap.
At this point the elevation difference of the icecap’s edge from top to bottom is not significant, only about 1,500 feet or so, though this is a very rough estimate. As with all other images of the ice cape’s edge, there are many many layers visible, all indicating a different cycle in the climate history of Mars as its rotational tilt swings from about 11 degrees to 60 degrees over eons.
Moreover, at this point there is likely not that much difference between the terrain on top and the terrain below. Both will be mixed ice and dust and coarse rocks, though the percentages will be shifting towards less ice as we go down.
The white rectangle on the ice cap’s left edge on the overview map to the right marks the location of Rupes Tenius, which extends more or less from here to the east, where Chasma Boreale begins.
The edge of the north pole ice cape at the top of this overview map is much steeper and higher then at Rupes Tenius, and is also where MRO has spotted numerous avalanches occurring, as they happen.. At the more subdued cliffs of Rupes Tenius such avalanches have not yet been seen, though it is likely they happen, though not as frequently, and certainly not with as much drama because the cliffs are not as high.
The answer to many questions about the geological history of Mars is locked in these ice cap layers. All geologists need to do is to drill some long core samples into the ice cap, either here or in fact anyone on the cape. A review of that core will then quickly outline that entire geological history, and help explain other geological features everywhere else on the planet.
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