Ancient Martian landslides

Ancient Martian landslides
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on December 23, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The image was labeled “Landslides in Orson Welles Crater” because the full photo shows at least two large and obvious slides, with the biggest shown to the right.

These avalanches are likely ancient because both have craters on them suggesting the material has not moved for a very long time. Yet when both flowed they did so almost like mud, the material moving downhill almost in a single blobby mass. Both have this look, as do many Martian landslides, which I think is why the scientists usually label them mass wasting events.
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Where the flood lava of two gigantic Martian volcanoes meet

Where the flood lava of two gigantic Martian volcanoes meet
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Today’s cool image illustrates once again the importance of looking not simply at the picture but at the surrounding larger context in order to understand the Martian features within the photograph.

The photo to the left, cropped, reduced, and sharpened to post here, was taken on January 31, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The location is at 26 north latitude, so it is in the dry equatorial regions. It shows what appears to be a large Martian flood lava plain, with at least two different flood lava events appearing to flow to the northeast, with the second only partly covering the first.

From this high resolution image it seemed probable that the source of the flow was from the southwest, an assumption that at first glance is strengthened by the overview map below.
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Confused glaciers in a Martian crater

Confused glaciers in a Martian crater
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Cool image time. The picture to the right, cropped to post here, was taken on February 2, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows a strangely blobby crater in the northern mid-latitudes where glacial features are frequently found inside craters.

In this case however the glacier seems very confused. As this is in the northern hemisphere, you would expect glacial material to survive on the north-facing southern interior slopes of the crater, where there is year-round less sunlight. The mottled eroded terrain in the south part of the crater floor suggests this. However, the crater also clearly has a terraced glacier on its south-facing northern interior slopes.

Why has the glacial material survived in both places, but not in the center of the crater?

In addition, there is that strange roughly circular feature attached to the south side of the crater. What formed it? Is it a glacier on the plains surrounding the crater? Or are we looking at volcanic material?

This crater is also unique. The crater just to its southwest (partly seen in the cropped image above), is a much more typical glacial-filled mid-latitude crater, its interior material more evenly distributed and its circular rim only slightly distorted.
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A half-mile high Martian cliff on the verge of collapse

A half-mile Martian cliff on the verge of collapse
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on December 24, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows erosion gullies coming down off a mountain side, just north of a massive cliff that I estimate to be around 2,000 to 3,000 feet high.

Note the north-south-trending cracks. These suggest that this entire half-mile-high cliff face is slumping downward, cracking as it does so. The cracks at the start of the high flat-topped thumb-shaped mesa near the image bottom are especially intriguing. They suggest that this entire mesa might eventually separate and give way.

There is a specific reason this cliff face is slumping, as shown in the overview map below.
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A verde valley on Mars

A verde valley on Mars
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In the southwest where I live, a valley dubbed “verde” (which means “green” in Spanish) is generally a place with a somewhat persistent river with lots of lush plant life. The Verde Valley in Arizona is the perfect example, with “close to 80% of the valley’s land … national forest.”

On Mars there is also a verde valley, but the name is not descriptive in the least. The picture to the right, rotated, cropped, and reduced to post here, was taken on January 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows one section of the Martian Verde Vallis, draining south to north.

The dark rippled patches inside this shallow canyon are sand dunes. In fact, though MRO has not taken many high resolution images of Verde Vallis, every one shows the valley with further patches of ripple dunes. See for example this image of a section of the valley just a bit farther north.
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The ubiquitous presence of ice in the Martian mid-latitudes

Ice in the Martian mid-latitudes
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Cool image time! The picture to the right, rotated, cropped, rotated, and sharpened to post here, was taken on November 28, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “crater with mesa”, it gives us another example of the presence of glacial ice in the mid-latitudes of Mars.

That mesa is what planetary scientists have labeled “concentric crater fill,” a glacial feature found in numerous craters throughout the mid-latitude bands from 30 to 60 degrees latitude. The ground in the terrain surrounding the crater could be also be impregnated with ice, but based on the location as shown in the overview map below, it is just as likely to be lava.

In fact, the location of this particular crater illustrates why concentric crater fill might become the best source of ice for future colonists.
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Endless ripple dunes in Mars’ third largest impact basin

Ripple dunes in Mars' third biggest impact basin
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Cool image time! The picture to the right, cropped to post here, was taken on November 30, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The section cropped shows only a small portion of the endless ripple dunes seen in this area. The color strip provides us some interesting other details as well as mysteries. The orange indicates dust on the ridges as well as the higher terrain near the center of the picture. The green in the hollows as well as to the east and west suggests coarser materials that have settled in lower elevations. This supposition is reinforced by the orange area near the bottom of the picture where the ripples have mostly dissipated. This is a high spot, and we appear to be looking at a dusty surface. (This impression is clearer in the full image.)

The latitude is high, 48 degrees south, but as far as I know orbital images have not found a lot of ice evidence in this part of Mars.
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Geological evidence of past glacier found in Mars’ dry equatorial regions

Overview map

Scientists have uncovered geological evidence of a past glacier in westernmost end of the giant Martian canyon Valles Marineris, right at the point where it transitions into the complex chaos region dubbed Noctis Labyrinthus. The white dot on the map to the right indicates the location.

The surface feature identified as a “relict glacier” is one of many light-toned deposits (LTDs) found in the region. Typically, LTDs consist mainly of light-colored sulfate salts, but this deposit also shows many of the features of a glacier, including crevasse fields and moraine bands. The glacier is estimated to be 6 kilometers long and up to 4 kilometers wide, with a surface elevation ranging from +1.3 to +1.7 kilometers. This discovery suggests that Mars’ recent history may have been more watery than previously thought, which could have implications for understanding the planet’s habitability.

โ€œWhat weโ€™ve found is not ice, but a salt deposit with the detailed morphologic features of a glacier. What we think happened here is that salt formed on top of a glacier while preserving the shape of the ice below, down to details like crevasse fields and moraine bands,โ€ said Dr. Pascal Lee, a planetary scientist with the SETI Institute and the Mars Institute, and the lead author of the study. [emphasis mine]

You can read the paper here [pdf]. The research specifically suggests that near surface water ice in the dry equatorial regions of Mars could have been there much more recently that previously believed. It also suggests, by the rarity of this discovery, that there is likely almost no near surface ice in the equatorial regions, at present.

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A Martian crater, ice, and dust devil tracks

A Martian crater, ice, and dust devil tracks
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 2, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It is once again a terrain sample image, taken not for any specific research but to fill a gap in the schedule so as to maintain the camera’s proper temperature.

What this picture shows is that even though Mars has a thin atmosphere that produces dust devils, the propagation of dust devils is not uniform across the red planet’s surface. In this picture there are a lot of devil tracks, going in many different directions. Yet few of the many cool images I post from MRO show this number of tracks. In many cases the ground might not be agreeable to leaving tracks, but that cannot be the entire explanation.
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Splats on Mars!

Splats on Mars
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Cool image time! The picture to the right, cropped and sharpened to post here, was taken on February 3, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a number of crater splats of varying sizes. If you look at the full image, you will find several even bigger splats to the north of the one in the picture to the right. You will also see many more similar-sized crater splats to the south.

I cannot provide any confident explanation about what caused these splats, other than to assume that most here are secondary impacts from ejecta thrown out by a larger impact somewhere nearby. I also assume all these small impacts occurred at the same time because they all appear to have hit the ground when it had the same thick liquid consistency, a condition that was probably temporary. Note for example how many of the other craters in the full image do not have this same splattered look.
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Ice volcano in the Martian high northern latitudes?

Ice volcano on Mars
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That the Martian surface becomes increasingly icy as one approaches its poles is becoming increasingly evident from orbital images. Today’s cool image provides us another data point.

The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on January 4, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It is once again another terrain sample image, taken not as part of any particular research project but to fill a gap in the camera’s schedule so as to maintain its temperature. With such pictures, it is hard to predict what will be seen, though the scientists try to find interesting things. In this case the camera team succeeded quite nicely, capturing what appears to me to be a small volcano with two calderas.

This volcano however has almost certainly not spouted lava but mud and water.
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Cracks in Martian lava

Cracks in Martian lava
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Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on January 25, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It was taken not as part of any specific research project, but to fill a gap in MRO’s picture-taking schedule in order to maintain the camera’s temperature. When such pictures need to be taken, the camera team tries to find something of interest in the area to be shot. Sometimes the picture is boring. Sometimes fascinating. Today’s picture I think falls into the latter category.

This is a lava flood plain, as shown in the overview map below. The meandering ridges are likely what geologists call lava dikes, places where lava was extruded out through a fissure. This suggests that the flat flood lava was an older crust, and that there was hot molten lava below it that eventually pushed its way up through cracks in that crust.

This hypothesis however is not certain, as the meandering nature of the ridges does not correspond well with what one would expect from such crustal cracks.
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Flat-topped mesas in the icy northern lowland plains of Mars

Flat-topped Martian craters
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Cool image time! The picture to the right, cropped and rotated to post here, was taken on December 27, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what the scientists have labeled “flat topped hills in Utopia Planitia.”

Utopia Planitia is the largest impact basin on Mars, approximately 2,100 miles across and located in the northern lowland plains.

Orbital evidence strongly suggests it is a region with a lot of near surface ice. The picture to the right reinforces that conclusion, as the entire flat plain surrounding these buttes appears like an ice field. Moreover, the full image shows many craters filled with glacial features, most of which also have softened features, as if with time the ice that impregnates their material has sublimated away.
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An inactive volcanic vent on Mars

An inactive volcanic vent on Mars
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Cool image time! The picture to the right, rotated, cropped, and reduced to post here, was taken on October 5, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled by the science team as “Vents and Lava Flows on Flank of Pavonis Mons,” the section to the right shows the picture’s largest vent. The downhill grade is to the south.

In the full photo you can see that this vent sits on top of a flat mound of hardened lava, all of which flowed from the vent in the distant past. The main flow of course went to the south, out the channel and down the flanks of Pavonis Mons, the middle volcano in the line of three just to the west of Mars’ giant Valles Marineris canyon. The caldera peak of Pavonis Mons is about 35 miles away, and sits at a height of 47,000 feet elevation, far higher than Mount Everest but still only the fourth highest Martian volcano.

In the full picture, the entire surface also generally flows south, except for a crack that goes from northeast to southwest, possibly caused when the mountain flank sagged to the south.
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Sightseeing in the region near the Starship Mars landing zone

Sightseeing in the region near Starship's landing zone
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Cool image time! The picture to the right, cropped and reduced to post here, was taken on November 30, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a bulbous hill in the icy northern lowland plains of Mars. That it is icy here is indicated by the glacier features that appear to fill the small crater near the bottom of the picture.

You can get a better sense of stark alien nature of this terrain by looking at an MRO context camera image of the same area, taken on April 1, 2008. The subject hill is the first hill on the image’s west side, going from the top. This is a flat plain interspersed with crater splats, mounds of a variety of sizes, and a puzzling meandering dark line that suggests a crack from which material is oozing.

The geology to be studied here might be endless but for tourists the views will be astounding in their alienness.
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A Martian glacier waterfall?

A Martian glacier waterfall?
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Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken on October 25, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small meandering canyon that appears to drain into a larger side canyon, all part of a region of chaos terrain dubbed Galaxias Chaos in the Martian northern mid-latitudes.

Though the latitude is 35 degrees north, where we should see lots of evidence of glacial features, especially because this is chaos terrain — terrain unique to Mars — that generally appears formed by such processes, I find few outright obvious glacial features in this cropped portion or in the full image.
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The barren and icy northern lowland plains of Mars

The barren and icy northern lowland plains of Mars
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Cool image time! The picture to the right, cropped and sharpened to post here, was taken on January 2, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Taken to fill a gap in the camera’s planned image schedule in order to maintain its temperature, the location was in this sense picked not for any particular scientific research project, but because the camera team decided they might find something interesting at this spot.

What they found is a vast flat plain of polygons, a feature found frequently on the surface of Mars and thought to be formed from processes similar to the drying that creates similar polygon cracks in dried mud here on Earth. In this case, the cracks are almost certainly in ice. As Colin Dundas of the U.S. Geological Surveyโ€™s Astrogeology Science Center in Arizona explained to me previously,
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Layers upon layers on Mars

Layers on Mars
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Today’s cool image once again illustrates that the geology of Mars will almost certainly center on a study of layers, as increasingly the orbital and rover images are telling us that the red planet is covered with innumerable layers, one after another, each created by another cycle, some seasonal, some global, and some related to climate and the planet’s fluctuating rotation tilt as well as its orbit around the Sun. And some might also be random volcanic events, unrelated to the cycles.

The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 10, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled by the science team “Layering in western Arabia Terra”, this section only shows a small amount of the layering visible in the full image. From east to west the ground rises in a series of terraces, each representing a different layer of distinct geology.
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Meandering ridges in Greg Crater

Meandering ridges in Greg Crater
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on November 29, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label “curved ridges.”

These might be inverted channels, the beds on which either water or ice flowed, compacting it down so that it became very resistant to erosion, and thus remains when the surrounding terrain was worn away. However, none of them seem to follow any grade. A more likely explanation is that these are ancient moraines, the debris pile pushed ahead of a glacier and then left behind when the glacier goes away.

The location is the reason I favor this explanation.
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Soft Martian buttes

Soft Martian buttes
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 1, 2023 by the high resolution camera on Mars Reconnaissance Orbiter to fill a gap in its shooting schedule so that the scientists could maintain the camera at its proper temperature.

In other words, the picture was not taken as part of any particular research project. Its target was in a sense chosen almost at random, though the science team always tries to find something of interest in such situations. In this case I think they succeeded, as these soft terraced buttes illustrate well the alien nature of Mars. The ground is barren, with absolutely no evidence of any life, and it appears that the buttes have been softened and eroded by eons of wind action. You can see evidence of this by the handful of dust devil tracks that cross the buttes.

There is more.
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