Click for full image.
As a break from Wuhan flu madness I give you another cool image, cropped and reduced to post here, taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I call this stucco on Mars because that is exactly what it looks like. It is as someone laid down a layer of damp concrete and then ran over it roughly with a trowel to raise the knobs scattered across the surface.
The uncaptioned MRO image calls this “Aligned Mounds with Broad Summit Pits”. Those aligned mounds run across the top of the image. I suspect they are pedestal craters, left over because the impact had packed and hardened the crater so that it resisted erosion as the surrounding terrain was worn away.
The two insets, posted below at full resolutoin, focus on one of those pedestal craters as well as the distinct mesa at the bottom of the photo.
This particular mound is intriguing because it seems to really be a cluster of four craters packed close together. One of smaller craters even seems to have a central peak. If these were caused by an impact, it was likely a single event, such as multiple pieces hitting at the same time, either from a shattered asteroid or from secondary ejecta from a nearby larger impact.
If these pits were not made by impact, I don’t have a clue what caused them. Though this certainly doesn’t look like a typical volcanic feature pushed up from below, it certainly could be, considering the different gravity and chemistry of Mars. In that alien environment it would be a big mistake to expect such things to look just like they do on Earth.
The mesa near the bottom of the photograph, shown to the right, provides evidence that considerable surface material here has eroded away. That the top of the mesa appears much higher than the top of the mounds just adds a bit of new complexity to this geology that needs explaining.
In fact, I wish I had some information on the actual height of this mesa. It appears we are looking straight down upon it, so it is difficult to estimate a height. The impression given however is of some considerable height. From the side this straight-sided pinnacle should look quite impressive.
The map to the right gives us some context. This stucco is located in the southern highlands, near the transition zone down to the northern lowlands, and about 800 miles to the west of Jezero Crater, where the rover Perseverance will hopefully land successfully in 2021.
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