Tag Archives: ice scarps

The range for exposed ice scarps on Mars keeps growing

Overview of ice scarp locations on Mars

In January 2018 scientists announced the discovery of eight cliffs with visible exposed ice layers in the high mid-latitudes of Mars. At the time, those eight ice scarps were limited to a single crater in the northern hemisphere (Milankovic Crater) and a strip of land in the southern highlands at around latitude 55 degrees south.

In the past two years scientists have been using the high resolution camera on Mars Reconnaissance Orbiter (MRO) to monitor these scarps for changes. So far they have seen none, likely because the changes are below the resolution of the camera.

They have also been able to find more scarps in the southern hemisphere strip beyond that strip at 55 degrees south.

Now they have found more scarps in the northern hemisphere as well, and these are outside Milankovic Crater. As in the south, the new scarps are still all along a latitude strip at about 55 degrees.

The map above shows with the black dots the newer scarps located in the past two years. The scarp to the east of Milankovic Crater is typical of all the other scarps, a steep, pole-facing cliff that seems to be retreating away from the pole..

The scarp to the west of Milankovic Crater is striking in that it is actually a cluster of scarps, all inside a crater in the northern lowland plains. Moreover, these scarps are more indistinct, making them more difficult to identify. According to Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Arizona,
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Ice! Ice! Everywhere on Mars ice!

Ice scarp in Milankovic Crater
Click for full image.

In January 2018 scientists announced the discovery of exposed ice in a number scarp cliff faces found in the high-mid-latitudes of Mars.

These scarps, which have so far been found in one southern 50-55 degree latitude strip and in one crater, Milankovic, at the same latitude in the north, are important because they are one of the first places on Mars in its lower latitudes where we have found ice actually exposed and visible, not buried like the many buried glaciers very near the surface found in the 30 to 60 degree northern and southern latitude bands.

Since that press announcement, scientists have been monitoring these sites for changes, as well as expanding their survey to see if they can locate more of these scarps.

Overview map

My previous posts on this subject were mostly focused on that southern strip near Hellas Basin, as shown on the map on the right. In reviewing the most recent image download from the high resolution camera on Mars Reconnaissance Orbiter (MRO), I noticed that the only new images of ice scarps were taken in the northern location, in Milankovic Crater, as indicated by the white dot north of Olympus Mons. The first image above shows the north-facing scarp of one of these images, cropped to focus in on the color section where, if you look close, you will see a strip of blue across the base of the scarp. That’s the ice layer, exposed as the scarp sublimates away over time from the north to the south.

over view of all MRO images taken so far in Milankovic Crater

This scarp, labeled #2 on the overview map of Milankovic Crater on the right, is located inside the crater’s eastern rim. The second image, posted below and labeled #1 on the overview map, shows a wider area of several ice scarps located on the inside of the crater’s southwestern rim.

The red boxes in the overview map indicate all the images taken by MRO inside this crater. If you go to the camera’s archive and focus in on Milankovic Crater at 54.5 degrees north latitude and 213.3 degrees longitude, you can then click on each red box to see the high resolution image. In practically every image along the crater’s inside rim can be found numerous scarps.
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The expanding range for Martian ice scarps

Another ice scarp
Click for full image.
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The discovery in January 2018 of a number of Martian cliff faces, or scarps as the scientists dubbed them, with a visible and apparently very accessible underground layer of ice, had significant ramifications.

First, it proved that, in at least one area south of Hellas Basin and one spot in the northern hemisphere, an underground ice table existed on Mars at latitudes as far south as 55 degrees. Scientists had theorized that this ice table, comparable to the water table on Earth, existed, but here was visible proof.

Second, the discovery showed places where water could be accessed relatively easily by future colonists. There are plenty of indications from orbiter images and lander/rover data that water is present in many places on Mars, but here the water appeared almost pure and could be obtained without major digging or processing. Whether that ice table extends even farther south, making it even more accessible, remains as yet a scientific question.

In the next few months the scientists involved in this research located more ice scarps in areas beyond the range of those initial discoveries. Since then however even more scarps have been found, including the scarp in the image above and to the right, cropped, reduced, and annotated to post here.

This particular scarp is located inside a crater. The uncaptioned release from the high resolution camera on Mars Reconnaissance Orbiter (MRO), described it as a “Scarp in mantling material.” According to Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Arizona,
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