The whittling away of Mars’ biggest volcanic ash field
Click for original image.
Cool image time! The picture above, cropped to post here, was taken on July 2, 2026 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
The science team labels this “layers in a low spot in Aeolis Mensae.” Aeolis Mensae is a high plateau of volcanic ash, part of the vast Medusae Fossae Formation, the largest volcanic ash field on Mars, as shown on the overview map to the right. This image however is inside a 4.5-mile-wide canyon, about 1,500 feet deep, that cuts into Aeolis about 25 miles, as shown by the inset. The white bar indicates the area covered by the picture above, with the elevation drop from the east to the west about 770 feet.
So what are we looking at? My guess is that this canyon was somehow carved out of that plateau of volcanic ash, with the stippled canyon floor a series of exposed layers going downhill to the west. I also suspect the erosion was mostly from wind, considering the delicate nature of each upper layer. The prevailing wind in this region are mostly coming from north, based on global dune patterns. As it is funneled into this canyon it is likely pressed against that eastern wall, where it swirls about and peels off dust to carry it away. The result are the layers and delicate features.
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