Tag: geology

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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 23, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). This one-mile-wide unnamed crater was a featured image last week by the science team. As noted in the caption, written by Chris Okubo of the U.S. Geological Survey:

This area was covered by a large flood of lava, which we see as the generally flat areas surrounding the crater. As the lava flowed across, some of it flowed into this crater through a low spot along the crater rim.

Once in the crater, the lava heated ground water or ground ice in the floor, causing the water to boil and turn into steam. This steam then exploded through the overlying lava and created small, ring-shaped formations. These are called ”rootless cones,” and they record the presence of ground water or ground ice in the crater floor at the time of the lava eruptions.

In other words, when this crater was flooded with hot lava, it was filled with ice or water. That fact is significant because of the crater’s location, as shown in the overview map below.
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Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on May 31, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The camera team label this “patterned ground.” And it is indeed. Though the topography is almost flat for large distances, the ground itself has these various patterns on it, from meandering small ridges to stippled roughness to very smooth sections.

The location is at 4.6 degrees north latitude, in the dry equatorial regions of Mars. No near surface ice created these features. All we can deduce from this picture is that this landscape is relatively young, as there are no craters seen.

So what caused these features? The location as always provides a clue.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 29, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It falls into what I call my “What the heck?!” category of Martian land-forms, simply because their shape is so strange and inexplicable it is difficult to conceive a geological process that could create them.

Nor does it help much that we know what these land-forms are made of. The white dot on the overview map above marks the location, inside the 2,000-mile-wide northern mid-latitude strip I label glacier country, because almost every image taken shows glacial features. In this case, this strange geology is located on the floor of a canyon that is part of a large region of chaos terrain, a landscape typical of glacier country. This floor, as well as all the low areas, seems filled with glacial flows. This particular canyon appears to roughly flow downhill to the northwest, though the downhill grade in the entire region varies widely in all directions.

Based on all the orbital data, these flows are glacial in nature, the ice protected by a thin top layer of dirt and debris. The strange features at the top of all the small mesas in the picture above suggest that the wind possibly blew off the dirt and debris, exposing the ice and allowing it to sublimate away. This in turn produced the knobby hollows at the top of each mesa.

I am guessing, and no one should trust my guess considering I only make believe I’m a geologist on the internet.

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In honor of our just completed visit to the south rim of the Grand Canyon, today’s cool image takes us to another location on Mars that to me appears a perfect place to install some hiking trails. The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 30, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The image shows a two-mile wide canyon with a number of scattered narrow mesas within. The north and south rims rise about 550 feet above the canyon floor. The two mesas labeled “A” and “B” rise about 200 and 100 feet respectively.

The hiker in me immediately imagines what a great hike it would be to go up the western nose of either ridge and walk along its crest. The knife-edge nature of ridge “A” would mean that for a large majority of the hike you’d be at the north and south edges at the same time.
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Today’s cool image returns to the Martian north pole. The picture to the right, rotated, cropped, reduced, and enhanced to post here, was taken on July 3, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the top of a ridge near the edge of that icecap, with dunes visible in the hollow several thousand feet below.

The angle of this picture does not show us the many layers on the cliff leading down to those dunes. It does show evidence, however, of the top few layers on the flat crest of that ridge. The white lines delineate those layers, each line marking the edge of a series of wide terraces.

The dunes in the canyon below are of interest because their source is likely the dust that is mixed into thick icecap’s ice. As that ice sublimates away on the face of the cliff, the dust falls into the canyon, where it is trapped.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 1, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels it clumsily as “North Polar layered deposits structural geology in icy layers”. What we see are the many layers that make up the north polar cap, produced by the red planet’s many climate cycles that scientists think Mars has undergone over the eons as the red planet’s rotational tilt, or obliquity, rocked back and forth from 11 degrees inclination to as much as 60 degrees. At the extremes, the ice cap was either growing or shrinking, while today (at 25 degrees inclination) it appears to be in a steady state.

These layers are a mixture of ice and dust. The variations from dark to light likely indicate changes in the amount of dust in the atmosphere. Dark layers suggest the atmosphere was more dusty due to volcanic eruptions. Light layers suggest the planet’s volcanic activity was more subdued.

At least that’s one hypothesis.
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Cool image time! The picture to the right, cropped and sharpened to post here, was taken on July 2, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Labeled simply as “wavy terrain” by the MRO science team, it shows a relatively flat plain of hollows and terraced ridges that suggest the prevailing winds come from the west-southwest. As they blow, they slowly cause the layers of material to peel away, exposing those terraces.

This wavy landscape extends for many miles to the west, covering a region 135 by 160 miles in area. The layering and wavy nature of the terrain suggests the material here is fragile and easily peeled away by the winds of Mars’ very thin atmosphere. Think of the sandstone that forms Monument Valley and Canyonlands in the southwest United States, shaped almost entirely by wind.

And in fact, the overview map below confirms this.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was downloaded on July 1, 2025 from the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Labeled by the science team as a “flow,” it shows what appears to be a major collapse of the canyon’s south wall. The white dot on the overview map above marks the location, near the center of the 2,000-mile-long strip in the northern mid-latitudes of Mars that I label “glacier country” because almost every single high resolution image of this region shows glacial features.

This picture is no exception. First, the canyon appears filled with a glacial material, though its flow direction is unclear. Orbital elevation data suggests that this collapse is actually at the canyon’s high point, with the drainage going downhill to the east and west.

Second, the collapse itself doesn’t look like an avalanche of rocks and bedrock, but resembles more a mudslide. Since liquid water cannot exist in Mars’ thin atmosphere and cold climate, the soft nature of the slide suggests it is dirt and dust impregnated with ice. At some point, either because of the impacts that created the craters on its southern edge or because the sun warmed the ice causing it sublimate away thus weakening the ground structurally, the entire cliff wall slumped downward to the north.

The canyon itself is about 800 feet deep. It likely formed initially along a fault line, with ice acting over time to widen and extend it.

Today’s cool image revisits Lycus Sulci, the largest mountain range on Mars, about 1,400 mile wide and 1,800 miles long. The overview map to the right gives a sense of the roughness and chaotic nature of this region, extending north from Mars’ largest volcano, Olympus Mons.

At present scientists are unsure of the geology that formed Lycus Sulci, and how it is linked with Olympus Mons. The wide view to the right suggests it is the remains of a very ancient lava flow descending from the volcano that over time has become eroded to produce this wildly knobby terrain. That hypothesis remains unproven however. There is also evidence that the material here might instead be volcanic ash, deposited in many layers and eroded away with time.

The location of the cool image below is marked by the white dot, with the inset providing us a wider view of the surrounding terrain. Note the two craters to the north and west. Both appear to have been partly filled by flows coming from the south and east, respectively, adding weight to the theory that this region formed from lava flow.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on April 24, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and was posted yesterday by the science team to illustrate the vast lava flows that cover much of Mars. From the caption:

This image captures the edge of a lava flow that partially buries older terrain in the Martian Southern Highlands. Where the edge of the lava flow made contact with the higher-standing topography, it formed a rumpled and ridged surface.

This lava flow is one of many massive flows that extend southwest from Arsia Mons, one of the largest shield volcanoes on Mars.

The mountain to the south rises about 3,700 feet above that rumpled lava ocean at its base.
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on Februay 11, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The camera team posted it yesterday as their own cool image, labeling it “A Fissure and Channel near Pavonis Mons”. From the caption:

A linear trough strikes northeast, then abruptly ends (or changes into a narrow ridge). Where the trough ends, a sinuous channel has an east-southeast strike, trending at almost a right angle to the trough. What happened to form these features?

We can speculate that first there was a southwest-to-northeast trending fracture or fault, perhaps associated with a volcanic vent. Groundwater (or some other runny fluid) coursed through the fault until overflowing and forming the sinuous channel. Continued movement through the fault carved a trough up to the overflow point.

The arrows indicate the downhill grades. Though this caption mentions groundwater, it is far more likely that the “runny fluid” was lava, as shown by the overview map below.
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Today’s cool image illustrates again why I rail against those who still claim Mars is dry. The picture to the right, cropped, reduced, and sharpened to post here, was taken on June 2, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The picture was labeled simply as a “terrain sample” by the MRO camera team, which almost always signifies that it was taken not as part of any specific science research project or by request by a scientist, but to fill a gap in the camera’s schedule in order to maintain its proper temperature. When such a gap-filler picture is required, the team tries to pick interesting features in that time frame, but don’t always succeed.

In this case, that time frame placed MRO over the northern mid-latitudes and a region I label “glacier country” because practically every picture taken in this region shows glacial features. This picture is no exception. The white dot in the overview map above marks the location, in the Protonilus Mensae area of the 2,000-mile-long strip of glaciers. The arrow in the picture itself shows the downward grade of the glacial flow. The small 2,000-foot-wide crater appears as if the impact occurred on soft ice, and the stippled terrain surrounding it appears to resemble the feature geologists have labeled “brain terrain”, a surface feature unique to Mars and associated with near surface ice, though its exact formation process is not yet understood.

Nor have I cherry-picked this image to prove my point. Its glacial-like features are very typical for this region of Mars. Note for example the inset with the larger crater to the northeast. It appears almost buried by this glacial material, which has poured through the gap in its southwest quadrant to fill it. A close look at all the low lying terrain shows similar glacial-like flows.

Mars is surely not a paradise. It is bone-chillingly cold almost all the time. Its atmosphere is so thin and lacking in oxygen you would quickly suffocate if you tried to breath it. But the data continues to suggest that the red planet has ample supplies of near-surface ice outside of its dry tropics. All future colonists will need to do is dig a bit and process the water out.

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Cool image time! The picture to the right, cropped, reduced, sharpened, and brightened to post here, was taken on May 1, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The scientists label this very simply as a “wall on Ausonia Cavis”. Ausonia Cavis — 31 miles long and 20 miles wide at its widest — is one of the many gigantic sinks found in many places on Mars. This particular cliff wall is about 2,000 feet high, though from rim to floor of the sink is closer to 3,000 feet.

The image was likely taken to get a closer look at those gullies flowing down the cliff wall. Previous research of similar cliff walls in this region has found what appears to be seasonal water frost in such gullies, and this image was likely taken to see if more such frost could be spotted here as well.
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