Tag: exploration

Cool image time! The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on August 5, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The central darker strip however comes from a September 27, 2008 image by MRO’s lower resolution context camera, inserted to fill in the blank section where one component on the high resolution camera has failed.

The picture focuses on what the scientists call a “pit interacting with a mound.” The 100-foot-deep pit is one of a very long meandering string of such pits, all of which suggest the existence of an buried river canyon into which debris is sinking. Altogether this particular string runs from several dozen miles, and its interaction with the triangular 300-foot-high mound suggests at first glance that the river that created the canyon did a turn to the left to avoid a large underground mountain, now mostly buried but revealed by its still exposed peak.

As is usual in planetary research, the first glance is often wrong. The overview map below provides a different answer, which says the formation of the aligned pits is related to the formation of the mound itself.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on June 30, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The science team calls the features here “narrow ridges”, but what makes these criss-crossing ridges interesting is their location within the picture.

They appear only inside the hollows and depressions, as if erosion had stripped out a top layer of softer material to reveal these ridges, made of a harder material. The almost random but straight orientations of the ridges also suggest they formed along faults or cracks, which also suggests we are seeing dikes where lava was pushed up from below.

Whether the eroded softer material is lava or volcanic ash is unclear, though it certainly resembles the ash layers seen in the giant Medusa Fossae Formation ash field on the opposite side of Mars.

As always, a wider look helps clarify things.
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Scientists mapping the location of mud volcanoes in chaos terrain in the dry equatorial regions of Mars have found numerous mud volcanoes, adding weight to the theory that an intermittent shallow lake once existed there.

The inset on the overview map to the right indicates the location of those mud volcanoes (of two types) in white and orange dots. What is significant is that none of the volcanoes are found on the mesas within this chaos terrain, only in the low flats below. From the caption:

Both feature types result from sedimentary volcanism – instead of magma upwells and eruptions, wet sediments, and salts reach and breach the surface, forming mounds and flows. Interestingly, these mounds only occur over the chaotic terrain floor materials and not on the mesas (red-shaded areas) they embay. This suggests a material composition link rather than a genesis by regional extensional forces generated by magmatic rises.

The blue areas are where this same science team think an intermittent inland sea once existed. This new data reinforces that hypothesis.

Features that look like mud volcanoes are common in the icy northern lowland plains. Finding them in the dry equatorial regions strengthens the theory that water was once common there. For this reason the scientists are proposing a mission to this location, especially because the possibility of water might increase the chances of discovering past life.

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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on June 23, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label “branching deposits,” two wiggling ridgelines with other ridges branching off from them.

What caused this? On Mars there are many such meandering ridges, all of which look like rivers that have positive relief, the opposite of what you would expect. The theory is that these weaving ridges were once canyons where either water or ice once flowed, compacting the streambed so that it was more dense than the surrounding terrain. When that terrain eroded away it left that streambed behind, as a raised meandering ridge.

That answer however might not apply here.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 13, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

In this one picture can be seen a glimpse of the entire history of the numerous lava eruptions that once dominated Mars when its giant volcanoes were active one to three billion years ago. The three aligned craterlike depressions likely signal the existence of a large lava tube below ground, placed there during an early large eruption, when the volcano was spewing out so much flood lava that such large tubes could form. The smaller meandering surface rills signal later eruptions that carried less flood lava and thus produced a smaller drainage features.

And finally, the rough and cracked appearance of the surface indicates the ancient age of those last eruptions, probably laid down about a billion years ago. Since then, the volcano has been dormant, and the frozen lava here has had time to erode, become roughened, and show signs of slowly wearing away.
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Cool image time! It is always dangerous to come to any quick conclusions about what you see from pictures from another planet. The photograph to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 19, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what at first glance looks like a surface similar to frosting seen on window panes on Earth in the winter, where water condensation freezes to form crystalline patterns.

Your first glance would be wrong. This terrain is about 120 miles north of the Martian equator, placing inside the dry equatorial regions where no near-surface ice is known to exist. If this geological feature is formed by the same condensation processes that create ice frost, then it must involve the deposition of some other type of material.

The explanation would also have to account for the change in the terrain, from finely patterned on the right to more crystalline on the left.
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