Tag: geology

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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on November 27, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this “exposed crater floor materials”. While properly vague, that hardly suffices. This image could easily fall into my “What the heck?!” category of Martian geology that is difficult to understand, no less explain.

The color strip suggests that dust dominates near the top and bottom, though dust is also present in the middle. The patches with the bluish tint in the middle suggests these lighter swirls and patches are bedrock.

Of course, none of that explains the weird shapes of these patches, nor why they exist at all.

Before delving into those weird shapes, we must note the two vertical black strips to the right of the color strip, indicating a gap in data. Such gaps have been appearing more frequently of late, suggesting MRO’s age, almost a decade in orbit around Mars, is beginning to show itself. A failure in 2023 in one filter band of the high resolution camera already leaves blank the color swath in black and white images. These new blank strips indicate further issues, warning us that we must be prepared for the loss of this camera and orbiter in the somewhat near future.
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Today’s cool image once again illustrates the fact that most of Mars Mars is not a dry desert like the Sahara, as most news sources and the general public still believes, but a cold icy place similar to Antarctica, with plenty of near surface ice covering almost the whole planet, except for the dry equatorial regions (the one region we have sent almost all our landers and rovers).

The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on November 26, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows one small section of the floor of an unnamed very old and eroded 82-mile-wide crater located in the northern mid-latitudes of Mars.

That location is indicated by the white dot on the overview map above. This part of the mid-latitudes is a region I dub “glacier country”, a 2,000-mile long strip where practically every image taken there shows very obvious glacial features.

Today’s image is no different. The 2-mile-wide crater in the upper left appears blobby, as if the impact had landed in mud. Its interior is filled with what the scientists believe is glacial debris. The surrounding landscape has a similar appearance, as if the ground was slushy and easily misshapen by seasonal temperature changes. To the southwest of the crater, within what appears to be a surrounding splash apron, there appears to be an eroded drainage channel, likely created by the flow of glacial ice downward.

So, when you read articles telling you Mars is dry and scientists are still hunting for water there, know that whomever wrote that article had no idea what he or she were talking about. The scientists studying Mars know that Mars has lots of water. Except for the tropics below 30 degrees latitude, there is near surface ice everywhere. Their questions revolve instead on figuring out how deep and extensive it is, and how it has shaped Mars’ overall geology.

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Today’s cool image could also be entered into my “What the heck?!” category of strange Martian geology. The picture to the right, cropped, reduced, and sharpened to post here, was taken on October 19, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this as “Round Deposits in Crater.” And yup, that’s what we have, round and flat small mesas inside an unnamed 3,500-foot-wide very shallow crater (no more than 10-20 feet deep) that also appears to be sitting higher than the surrounding landscape. Furthermore, several nearby craters are also raised, with one having its own oblong flat interior mesa. Moreover, the terrain around the crater appears stippled, as if it has been eroding or sublimating away.

The latitude, 37 degrees north, provides the first clue for explaining this weird landscape.
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Just because there are no new images coming back from Mars at this time because the Sun is in the way does not mean we can’t enjoy more cool Martian images. The picture to the right, cropped, reduced, and sharpened to post here, was taken on October 20, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

Labeled merely a “terrain sample,” this means it was taken not as part of any particular research project but to fill a gap in the camera’s schedule. The camera team needs to take regular photographs in order to maintain the camera’s proper temperature, and when there is a long gap they add a terrain sample image to the schedule. Usually they try to pick some target of interest.

In this case the target is this 2,500-foot-high cliff, in which we can see a whole range of Martian geological mysteries. First there are the slope streaks on the cliff, a feature unique to Mars but as yet unexplained. Resembling avalanches, these streaks leave no debris piles at their base, do not change the topography in any way, and can appear randomly throughout the year, fading with time. Though the streaks in this picture are dark, streaks can also be bright.

Both the parallel ridges at the base of the cliff, as well as the cliff itself, are remnants of other major geological events, at least based on present theories.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on October 24, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The science team labels this simply as “irregular terrain.” It is far more than that. We are looking at a three-mile-wide shallow canyon, with what appear to be eroding glacial features on the canyon floor.

The location is at 35 degrees north latitude, so finding glacial features here is entirely unsurprising, especially because this location is the southern edge of the 2,000-mile-long mid-latitude strip in Mar’ northern hemisphere I label glacier country, because almost every picture shows such glacial features.

In this case, the channel also suggests a much more complex geological history, that could involve flowing water though flowing glaciers are increasingly becoming an alternative explanation.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on September 9, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels “an inverted channel.” From the caption:

Topographic inversion is a process where geologic features that were once low-lying, like impact craters or riverbeds, become elevated over time, like mesas or ridges. In this process, a crater or channel is filled with lava or sediment that becomes lithified [hardened]. If this infill is more resistant to erosion than the surrounding landscape, the less-resistant material can be eroded away by wind or water. The former crater or valley fill, being more resistant, remains elevated as the landscape around it lowers. The original low-lying feature becomes a mesa or ridge.

In this image, an ancient river network and nearby impact craters have undergone topographic inversion. Impact craters contain round mesas within them, and the stream channel is defined by a network of ridges.

The location of this inverted channel makes its history even more interesting.
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Cool image time! On October 7, 2025, the science team that operates HiRISE, the high resolution camera on Mars Reconnaissance Orbiter (MRO), took its 100,000th picture since entering Mars orbit in March 2006.

The objective of this observation is to better resolve sand dunes and the rocky material underneath them. These dark, eroded rocks may be the source for some of these Syrtis Major sand dunes. Our image was suggested by a high school student enrolled in the Jefferson County Executive Internship program in Colorado in 2023, one of many public outreach programs the HiRISE Team engages in.

To celebrate this accomplishment and the fantastic geology of the scene, students and staff in the HiRISE Photogrammetry lab constructed this digital terrain model. This oblique image highlights the hummocky mounds of the plains that border Jezero Crater, which are among the oldest on Mars.

That oblique image, cropped, reduced, and sharpened to post here, is to the right. The location is about 50 miles to the southwest of Jezero Crater where the rover Perseverance landed.
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Cool image time! The picture to the right, cropped, reduced, sharpened, and annotated to post here, was taken on October 27, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have also rotate the image so that north is to the top.

The science team labels this “Exposure of North Polar Layered Deposits,” an apt description of the horizontal red and grey and blue layers that dominate the image and make this geology look more like an abstract painting than a natural landscape. What we are actually looking at is a canyon 800-to-1,200 feet deep within the north polar ice cap of Mars.

The picture was taken in the summer with the Sun about 12 degrees above the horizon to the south. Thus, the northern cliff face is illuminated, revealing its many colored layers, while the south face is mostly in shadow, hiding those layers.
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