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Cool image time! Above is an image taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) in November 2018 of an area in the vast relatively featureless northern lowlands of Mars. I have rotated, cropped, and reduced it to post here.

I have also indicated two sections, indicated by the white boxes, that I have cropped out of the full resolution image to highlight some interesting features. Both images can be seen in full resolution below.

While the northern lowlands seem featureless from a distance, with few craters, a closer look always reveals many things that are both baffling and fascinating. In this case the region is called Galaxias Colles, a region of mesas and knobby hills. This particular image was dubbed “Cones in Galaxias Colles,” and was clearly taken to get a better look at these strange blobby features.
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Cool image time! In a sense, to announce that scientists have found an oddly shaped crater on Mars is to state the obvious. In the years since the first Martian fly-by by Mariner 4 in 1965, scientists have been discovering numerous odd-shaped craters on Mars, every single of which has challenged our assumptions about the planet’s geology. I myself have posted a half dozen such posts since January (January 7, January 10, January 14, March 26, March 27, June 12).

Yet, it is always worth looking when another one crops up, because of the fact that they challenge our assumptions about Martian geology. They are also always cool to look at! On the right, cropped and reduced to post here, is an image taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on April 19, 2019 of what the scientists have dubbed an “Odd Shaped Crater in Arabia Terra.”

Arabia Terra is one of the largest regions of the transition zone between the northern lowlands and the southern highlands. This crater is located, as shown by the red cross in the overview map to the right, near its northern edge, in an area where the descent into the northern lowlands is somewhat abrupt and broken up by large craters and chaos terrain.

The crater itself holds numerous geological mysteries. Its shape suggests two impacts of different sizes overlapping each other, but without any remnant of the inner rim of the second impact. Where did that remnant go? Or maybe this wasn’t caused by two impacts, but by one impact that reshaped the surface in this odd and inexplicable way.

Then there is the three teardrop-shaped patterns in the crater’s floor. They look like the brushstrokes of a giant-sized painter. Were they caused by the wind? And if so, why in this pattern?

Planetary geologists could probably come up with a dozen more questions. The number tells us how little we know about Mars.

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Cool image time! The image on the right, cropped to post here, was part of the monthly image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO). The release came with no caption, and was merely titled Aonia Terra, indicating that it was part of the vast cratered region ranging from 30 to 81 degrees latitude south of Valles Marineris.

These craters are at the high latitude of 73 degrees, so they are relatively close to the south pole. Based on what I have recently learned about the Martian poles, the higher the latitude the more water you will find saturated in the ground. In many ways one could refer to this ground as a kind of permafrost.

The lander Phoenix landed at about 68 degrees north latitude, slighter farther from the north pole, and was able to find water by merely scraping off a few inches of ground.

Thus, we should not be surprised by the muddy look of these craters. Their bolides landed on ground that was likely saturated with water, and went splat when they hit.

The scientific puzzle is why one crater seems to sit above the general surface, as if the ground resisted the impact, while the other seems to be mostly sunken, as if the ground was so soft that when the bolide hit, it sunk as if it landed on quicksand, leaving only a vague trace of an impact crater.

Don’t ask me for an explanation. I only work here.

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Cool image time! The picture on the right, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter in December 2018 and released earlier this year. It shows a filled fault/fissure in a region dubbed Cereberus Palus, located south of the giant volcano Elysium Mons and to the west of Olympus Mons. This region is also biggest and most extensive sections of the transition zone between Mars’s southern highlands and the northern lowlands. This area however is so far from the lowlands its geology is more likely influenced more by the volcanism that created Elysium Mons to the north.

The overview map to the right illustrates this geography, with the black square indicating the location of this image.

The image itself strengthens my uneducated conclusion. This region of Cereberus Palus is filled with many faults, cracks caused as the terrain was stretched by the rising volcano. In some cases, as shown here, the cracks became filled with lava from below, as indicated by the lighter color of the material in those filled cracks..

What struck me most about this image was the terrain on the picture’s right. Looks exactly like the stucco on the outside of my house. It is as if a plasterer came by before the lava solidified and ran his putty knife over the surface to create the multiple small ridges.

It is worthwhile checking out the full resolution image. The details are especially intriguing.