THEMIS Image of the Day, June 27, 2018. In this VIS image of part of Aram Chaos, the surface region is being dissected by linear valleys. As the dissection continues individual mesas will develop, creating the terrain termed chaotic. The linear nature of the valleys is most likely due to tectonic fractures.
Aram is a large and ancient impact crater which has been filled to the brim with later sediments. These became saturated with water, either when they were deposited or at some later time. Then in one of the martian climate’s grand changes, the water froze into ground ice.
Later still, after tectonic faulting, the ground ice melted and escaped along the fractures. This created the mesas by enlarging the fractures and eroding the sediment’s edges.
In this region of Aram Chaos the mesas are still large, with time the mesa edges will continue to erode and the mesas will become smaller and further from each other.
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