Tag: glaciers

A map of glaciers on Mars.

According to new research, scientists now think that the glaciers on Mars are almost pure ice, protected from sublimation by a thin cover of dust and debris.

Work over the last 20 years has demonstrated that at least some of these glaciers are mostly pure ice with only a thin cover of rock and dust, but according to a new paper published in Icarus, glaciers all over the planet actually contain more than 80% water ice, a significant finding. Ultimately, this means that Mars’s glacial ice deposits are nearly pure across the globe, providing a clearer understanding of Mars’ climate history and a possible resource for future utilization.

The researchers analyzed mid-latitude glaciers at five different locations in both the north and south hemispheres, and found that at every location the data suggested almost pure ice.

The map to the right, from earlier research, shows the prevalence of near-surface ice once you get above 30 degrees latitude. From the poles to the mid-latitudes it appears there is an ice sheet or “ice table” just below the surface. In the mid-latitudes glaciers dominate, as this appears to be the region where that ice is beginning to dissipate. In the equatorial regions little or no near-surface ice has been detected, though there has been some evidence in some places of ice at deeper depths.

This data once again demonstrates that Mars is not a desert like the Sahara, as we once believed. Instead, it more resembles Antarctica, where there is ice everywhere that simply needs to be processed for use.

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My headline is a bit of a guess, but it is an educated guess for today’s cool image. The photo to the right, cropped, reduced, and sharpened to post here, was taken on October 30, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The location, as indicated by the white dot in the overview map above, puts this impact in a relatively flat area of Deuteronilus Mensae, the westernmost chaos region of the 2,000 mile long mid-latitude strip I call glacier country.

In other words, there is likely a lot of near surface ice here, as this impact makes very plain. If you imagine dropping a pebble into a thick layer of soft ice cream, you might get a crater reminiscent of this. I use for comparison ice cream on Earth because the lighter Martian gravity probably makes Martian ice softer and more slushy.

As I have said many times before, Mars is strange, Mars is mysterious, and above all Mars is alien.

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Today’s cool image takes us back to the mesa in Mars’ glacier country that first clued me in on the prevalence of ice in the Martian mid-latitudes. The photo to the right, rotated, cropped, and reduced to post here, was taken on November 13, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows a viscous flow coming down from a hollow on that mesa’s southern wall.

The new image has likely been taken to see if anything has changed since the previous image was taken in 2014. Based on the resolution published at the MRO website, nothing seems to have changed, though with more sophisticated software higher resolution versions of the images are available that might show some changes.

In my first post about Mars’ glacier country in December 2019, this flow was one of four that I featured coming off this same 30-mile wide mesa, as shown by the first overview map below.
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Mars’ glacier country.

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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on December 12, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small patch of layered glacial features flowing in all directions. The overview map above marks its location by the red dot, at 40 degrees north latitude in the region dubbed Deuteronilus Mensae, on the western end of the 2,000 long strip from 30 to 60 degrees north latitude that I dub Mars’s glacier country because practically every image in this region shows glacial features.

What makes the glacial features in this picture so remarkable is their number, their somewhat chaotic nature, and the evidence of many layers, suggesting a cyclical process of ebb and flow over the eons.

Below I zoom into one section of this photo, showing that section at full resolution.
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Today’s cool image, taken on July 1, 2020 by the high resolution camera on Mars Reconnaissance Orbiter, is of a mound-like mountain on Mars that to all intents and purposes appears covered by glacial ice, some eroded, some not.

The image to the right, rotated, cropped, and reduced to post here, shows this mound. Both the flow coming down from the mountain top down the north slope as well as the flow in the north that appears to begin in a small crater suggest glacial features.

Even more convincing are what appear to be patches of glacial ice on the southern slopes, resembling the kind of glacial patches you see everywhere in Glacial National Park. The second photo to the right, taken by me on our visit to Glacier National Park in 2017, shows similar patches hugging the mountainside at Grinnell Glacier.

This Martian mountain is located in the southern hemisphere inside Hellas Basin on its eastern interior rim. (See the overview map below, with the location of this photo the small white box south of Harmakhis Valles.) Thus, you would expect the north-facing slope to get more sunlight (and more heat) than the south-facing slopes. Yet, from this image there appears to be greater erosion on the south-facing slopes. A puzzle indeed.
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Cool image time! The photo to the right, cropped and reduced to post here, shows the interior south-facing rim of a small crater in the southern cratered highlands of Mars. Taken on May 30, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), the image release is merely labeled “Gullied Slope”. The photo was taken as part of regular monitoring of these gullies since 2011 to see if they change from season to season. The 2011 image was captioned by planetary scientist Alfred McEwen, who wrote the following about the gullies:

These are erosional features with depositional fans. Some of the gully fans have a bluish color: these are probably quite recent deposits, less than a few tens of years old.

Since they were considered so very young, it makes great sense to look at them frequently. In making a quick comparison between the 2011 and 2020 images however I could not spot any changes, but that might be because the versions I downloaded are not at the fullest resolution.

This crater, at 39 degrees south latitude, is also worthwhile because its floor appears covered with glacial material, what scientists have dubbed concentric crater fill. As McEwen noted in his 2011 caption,

On the floor of the crater (bottom of this image) are ridges that likely formed from the flow of ice, perhaps a few million years ago.

Those glaciers, generally protected by thin layers of dust and debris, are considered inactive at this time in Martian geological history. The many ridges however hint at the many many cycles in the Martian climate, fluctuating between periods when these mid-latitude glaciers were growing while the polar ice caps were shrinking, and periods when the mid-latitude glaciers were shrinking while the polar ice caps were growing.

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Cool image time! The photo to the right, rotated and cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on May 25, 2020. The entire image was dubbed “Cluster of Filled Craters”, but I decided to highlight the crater of the cluster that was most strangely distorted of them all. The material that fills all the craters in the full image is almost certainly buried ice and is dubbed concentric crater fill by scientists.

This crater is located in the northern lowland plains the mid-latitudes between 30 and 60 degrees, where planetary scientists have found ample evidence of many such filled craters and glaciers.

Not only does the crater’s interior seemed filled with glacial material, its distorted rim suggests that it has been reshaped by glacial activity that might have covered it entirely over the eons as the mid-latitude glaciers of Mars waxed and waned with the extreme shifts that happen regularly to Mars’ rotational tilt. Moreover, there is strong evidence that in these lowland northern plains an underground ice table exists close to the surface, allowing for more distortion over time.

The overview map below provides some location context.
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Click for full resolution image.

Cool image time! The image to the right, rotated, cropped, and reduced to post here, was taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) on April 6, 2020.

The image shows the dying edge of a debris flow coming down from a mesa, the edge of which can be seen as the dark slopes in the upper left. The white arrows point up slope. It is located in the chaos terrain of a mid-latitude region called Deuteronilus Mensae, in the transition zone between the southern highlands and northern lowlands, where many such glacial-like features are found. I featured a similar nearby glacial edge only two months ago, where the image showed the glacier’s break up and collapse at its edge.

Here, the debris flow isn’t breaking up so much as crumbling away, its edge a line of meandering depressions, with the uphill slope covered with many knobs and tiny depressions, reminiscent to me of the many features I see in caves, where the downward flow of water shapes and erodes everything to form cups and holes and knobs, all the same size. If you click on the full resolution image and zoom into that debris slope and then compare it with the linked cave formation photo, you will see the resemblance.

We are almost certainly looking at a buried inactive glacial flow coming off that mesa, though it appears to be eroding at its foot. The overview image to the right shows the context, with the red dots indicating this image as well as similar features in adjacent mensae regions (featured in the linked images above). While the chaotic and rough terrain found along this transition zone does not make them good first settlement sites, the ample evidence of vast reservoirs of buried ice, combined with a variety of topography, will likely someday make this good real estate for those living on Mars.

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Cool image time! Using both Martian orbiters and rovers scientists are increasingly convinced that Mars has lots of buried glaciers in its mid-latitudes. These glaciers are presently either inactive or shrinking, their water ice sublimating away as gas, either escaping into space or transporting to the colder poles.

The image to the right, cropped and reduced to post here, shows some apparent proof of this process. Taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) on December 23, 2019, it shows a weird meandering ridge crossing the floor of a crater. The north and south parts of the crater rim are just beyond the cropped image, so that the gullied slope in the image’s lower left is actually a slope coming down from that rim.

My first reaction upon seeing this image was how much that ridge reminded me of the strange rimstone dams you often find on cave floors, formed when calcite in the water condenses out at the edge of the pond and begins to build up a dam over time.

This Martian ridge was certainly not formed by this process. To get a more accurate explanation, I contacted Dan Berman, senior scientist at the Planetary Science Institute in Arizona, who had requested this image. He explained:
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