Tag: Mars Reconnaissance Orbiter

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Today’s cool image is also today’s picture of the day from the science team of the high resolution camera on Mars Reconnaissance Orbiter (MRO. That picture, rotated, cropped, and reduced to post here, can be seen to the right. As the caption authors Sharon Wilson and Sarah Sutton write:

The smooth volcanic surfaces in the Gordii Fossae region are sometimes interrupted by long, narrow troughs, or fissures. These fissures form when underground faults, possibly involving magma movement, reach the near-surface, allowing material to collapse into pits or an elongated trough. This fissure appears to have erupted material that flowed onto the surface.

If you use your imagination, this trough resembles a gecko with its long tail and web-shaped feet!

This impression is even more evident in the wider image taken by MRO’s context camera below.
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on May 30, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the dusty dry floor of the chaos region of rough terrain in a side canyon of Valles Marineris, near its outlet. The color strip and the bright outcrops suggest that this terrain contains interesting minerals and resources. To determine exactly what those materials are however requires more information not available in this photo.

This ancient chaos terrain is the leftover eroded sea floor of a intermittent inland sea, leftover water from the catastrophic floods that are theorized to have flowed out of Valles Marineris and carved its gigantic canyons.

The overview map below shows this hypothesized sea.
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on August 29, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label an “inverted channel in Arabia Terra,” a small example of the more than 10,000 miles of fossilized rivers in this region on Mars that scientists have identified using MRO.

They are made of sand and gravel deposited by a river and when the river becomes dry, the channels are left upstanding as the surrounding material erodes. On Earth, inverted channels often occur in dry, desert environments like Oman, Egypt, or Utah, where erosion rates are low – in most other environments, the channels are worn away before they can become inverted. “The networks of inverted channels in Arabia Terra are about 30m high and up to 1–2km wide, so we think they are probably the remains of giant rivers that flowed billions of years ago. [emphasis mine]

Since this fossilized river is located at 11 degrees north latitude, smack in the middle of the dry equatorial regions of Mars, it has certainly been a dry desert for a very long time. You can see how barren the terrain appears by looking at the wider view afforded by MRO’s context camera below.
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Cool image time! The photo to the right, cropped, reduced and annotated to post here, was taken on July 30, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The left image shows a pit that the scientists label a “vent” near the giant volcano Pavonis Mons. The right image is identical, except that I have brightened it considerably to bring out the details in the shadowed area.

As you can see, this pit is filled, and does not appear to have any existing openings into more extensive underground passages.

The white dot on the overview map on the right shows this vent’s location, to the south of Pavonis Mons, and in line with the giant crack that splits three of Mars’ four largest volcanoes. The vent is even aligned the same as that crack, from the northeast to the southwest. The black dots mark the locations of the many cave pits found in this region.

Was this a volcanic vent? If you look at the full image you will see that this pit aligns with a shallower pit to the southwest, with a depression linking the two. Visually this suggests this is a faultline which in turn makes for a good outlet point for lava flow.

Though the data suggests this is a volcanic vent, that supposition is as yet unproven. The full image does not show much evidence of a flow from the pit, which suggests instead that we are merely looking at a spot where the ground cracked along fault lines.

Today’s cool image is another example of scientists finding cool things hidden within distant pictures. The small white rectangle on the overview map to the right shows us where we are heading, to the severely eroded lava plains to the southwest of Mars’ largest volcano, Olympus Mons.

The white spot is about 500 miles from the caldera of Olympus Mons. In elevation it sits about 58,000 feet below that caldera, more than twice the height of Mt. Everest. Yet, despite these great distances, the material at that white rectangle was almost certainly laid down during an eruption from Olympus Mons, thus illustrating the gigantic scale of volcanic events on Mars. Because of the red planet’s light gravity, about 38% of Earth’s, not only can lava flow farther, it does so much faster.

The second image below is a wide angle photo taken by the context camera on Mars Reconnaissance Orbiter (MRO) in January, 2012, rotated, cropped, expanded, and enhanced to post here.
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on July 2, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It provides us just one more clear example of the many glaciers found in that 2,000-mile-long strip of chaos terrain at 30 to 47 degrees north latitude that runs between the northern lowland plains and the southern cratered highlands, a region I like to call Mars’ glacier country.

What makes this glacial feature interesting is that these ice-filled alcoves are south-facing, which in the northern hemisphere means they get the most sunlight. Yet, the ice here remains, well-protected by its layer of dust and debris. Think of the dirty ice slush that manages to survive the longest on city streets in the spring. The dirt acts as protection so that the ice takes more time to melt.

The overview map as always provides our context.
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, shows one small section of a 30-mile-wide unnamed crater in the cratered equatorial regions of Mars northeast of Hellas Basin. Taken on July 21, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), the science team labeled merely as “Rocky crater fill.”

Being at 17 degrees south latitude, there shouldn’t be any ice features in this crater, and the high resolution image to the right seems to confirm this. All we see is an endless plain made up of innumerable small sharp rock ridges interspersed with small low areas filled with sand dunes. This is bed rock, and if its strange stucco-like appearance was caused by a past glacial era, that era is long gone.

Below is a mosaic showing the entire crater, created from two MRO context camera images.
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Cool image time! The photo to the right, rotated, cropped, reduced, and enhanced to post here, was taken on June 7, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The left image shows what the scientists have dubbed a “lozenge-shaped depression” in the middle of an unnamed 60-mile-wide crater in the southern cratered highlands of Mars. The right image shows the same exact depression, but I have brightened the photo in order to see the details in the shadowed depression.

Though the image is inconclusive, the bottom of the darkest spot in that depression cannot be seen, suggesting it could be an entrance into a larger void below.

Even if there is no voids below, why is this depression here? What caused it? The wider view of MRO’s context camera below might give us a hint.
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Today’s cool image provides a nice illustration why scientists have long assumed that in the distance past there had been catastrophic floods of liquid water on Mars. The photo to the right, rotated, cropped, and reduced to post here, was taken on July 6, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows an east-west gully cutting between mesas to the north and south.

Because the highest mesas seem to be aligned, this suggests they were once part of the same formation, and something came along to carve that gap and gully between them.

What made the break? The overview map below as usual provides some context, which also provides a possible explanation.
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Today’s cool image sits right on the southern edge of Mars’ northern glacier country, at 29 degrees north latitude. The picture to the right, cropped and reduced to post here, was taken of this location on June 4, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what appears to be the exposed and scraped bedrock and mesas on the floor of an unnamed 60-mile-wide crater.

That scraped bedrock is quite beautiful, reminiscent of the bare carved mesas and bedrock one sees throughout the southwest of the United States. To hike from that central valley to the top of the bright mesa would be a fine experience, especially because of the suggested change in colors in the color strip.

The overview map below gives more context.
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken by the wide angle context camera on Mars Reconnaissance Orbiter (MRO) in April 2019. It shows an area on Mars where a number of meandering curving channels flow downhill from the west to the east.

Earlier MRO images had already spotted these channels, so when this context image was taken the scientists also took a high resolution image of the same channels, with the white box indicating the area covered by the rotated, cropped, and reduced image below.

Both images are today’s MRO image of the day, where the MRO team notes that “The objective of this observation is to examine a complex network of channels. Some parts of the channels are quite curved.”
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on June 21, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The location is a very eroded crater at about 26 degrees north latitude. The image shows the crater’s crater floor, with a variety of bedrock-type features, sharp ridges, abrupt scarps, and flat smooth plateaus, with a hint of lobate glacial flows in the image’s southeast quadrant.

At 26 north latitude, it is unlikely that anything here is icy, unless it is very well protected by debris. Most of these features are almost certainly bedrock, though their formation could very well have been shaped by ice in past eons when this location was more amenable to water ice.

The wider MRO context camera image of the entire crater, plus the overview map, give a larger picture, and raise some interesting questions.
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Cool image time! The photo to the right, cropped, reduced, and rotated so that north is up, was taken on May 12, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the strange lacy patterns seen routinely in the very high northern latitudes surrounding the Martian north pole.

Located in a region of the vast northern lowland plains dubbed Scandia Tholi, such features are apparently common here. From a 2011 geology paper of the region’s geological history:

We find that Scandia Tholi display concentric ridges, rugged peaks, irregular depressions, and moats that suggest uplift and tilting of layered plains material by diapirs and extrusion, erosion, and deflation of viscous, sedimentary slurries as previously suggested. These appear to be long-lived features that both pre-date and post-date impact craters.

The small circular feature near the bottom of the picture appears to be a mesa, and might be a pedestal crater, so old that the surrounding terrain has worn away and left the hardened-by-impact crater as a butte. To its right is a larger circular mesa with its scarp well eroded into hollows. This might also be a pedestal crater, or not.

The white lacy patterns could be frost, either water ice or dry ice. That the white lace tends to favor the north-facing slopes lends support to this guess. The photo was taken in the early spring, so the thin mantle of carbon dioxide that falls to cover the polar region south to sixty degrees latitude is only beginning to sublimate away.

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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on June 17, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a somewhat straight depression with several wider and deeper pits along it.

The feature immediately suggests sinkholes that exist because the ground is sagging into voids below ground. Yet, both the straight and circular depressions also appear filled, showing no evidence that they connect to any below ground cavities.

Are the sinks the result of a fissure produced by a graben, when two large blocks shift relative to each other to cause a fissure to appear? Or are they evidence of an underground lava tube? Or maybe they are the filled remains of a now mostly buried canyon carved by water or ice?

As always, a wider view helps clarify things, though whether it answers the question is uncertain.
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on June 29, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The location is in Mars’ glacier country, that strip of chaos terrain that runs about 2,000 miles along the transition zone between the northern lowland plains and the southern cratered highlands at 30 to 47 degrees north latitude. This particular feature is located in Deuteronilus Mensae, the westernmost region of that strip of chaos.

I call this glacier country because practically every image taken by MRO’s high resolution camera in this region suggests the presence of glacial material covered by a protective layer of debris. The photo to the right is typical, though a bit more puzzling because of the depressions that appear to run along highpoints.

As usual, the overview map below helps explain what we are looking at.
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Cool image time! The photo to the right, cropped to post here, was taken on May 14, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels as “light-toned layered deposits.”

Their focus, rightly from a geologist’s perspective, is the contrast in color between different layers, suggesting different composition and thus a different formation history for each layer.

To me, what made this feature appealing is the thinness and number of its layers. It reminded me of fillo pastry, “unleavened flour dough formed into very thin sheets or leaves.”

If you look at the full image you will see that cropped section only covers one edge of a tongue-shaped plateau, with similar layers revealed along its entire cliff wall. It is almost like those layers have been peeling off for eons to leave the plateau behind.

The location below gives some context.
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