The first glacial evidence found on Mars back in 2007
Click for original image.
Cool image time! The picture to the right, cropped, reduced, sharpened, and annotated to post here, was taken on January 3, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the eastern wall of what the scientists call a graben, a large depression caused when the ground inside the depression suddenly shifted downward.
The elevation difference between the high and low points is about 3,500 feet. The streaks on the lower half of the cliff wall are slope streaks, a phenomenon unique to Mars that remains at this moment unexplained. Though the streaks resemble avalanches, they do not change the topography in any way, have no debris pile at their base, and appear instead to be a stain that appears at random times of the year that fades with time.
What is intriguing about this picture however is the wavelike floor on its western half. At first glance these waves suggest some form of dust dunes or lava flows, but neither conclusion appears correct. Instead, we are looking at what was one of the first discoveries on Mars of what scientists have determined to be glacial features.
Click for original image.
The green dot in the inset on the overview map to the right marks the location of this picture, on the northwestern flanks of the giant volcano Arsia Mons. The black dots mark the locations of pits — likely skylights into lava tubes — that have been featured as cool images previously. The MRO context camera image above, taken on January 21, 2007 and rotated so north is to the right, provides a full view of the entire graben depression, with those waves of material clearly appearing to flow to the north.
While the waves of material and their location on this giant volcano suggest they might be lava that filled the graben depression, a 2007 science paper using MRO images instead concluded that this material was an aging glacier covered with debris.
After detailed review of new observations, we interpret the fill material on the floor of the large graben at Arsia Mons to be waning stages of debris-covered glaciers that filled the graben in the past. The collections of ridges and furrows on the fill surface suggest that the two alcoves on the southeastern wall of the graben served as the accumulation areas for two large debris-covered glaciers that were the primary source of ice within the graben (Figures 3 and 4). Corresponding patterns of ridges and ridge packets on each of these glaciers (Figure 4) suggest that they formed simultaneously in the two cirque-like alcoves, with the same atmospheric source, and flowed northward along the long axis of the graben.
The paper from which I quote was one of the first that identified what appeared to be glacial features on Mars, here on the western flanks of Arsia Mons. Since then scientists have used MRO to take repeated pictures of the floor of this graben, monitoring it for changes. Unfortunately, the best images easily downloadable on the web do not have the resolution necessary for me to identify any changes, and I have not been able to find any more recent papers studying this graben. Since most of the glaciers on Mars are generally considered inactive, it is likely that this is the situation here as well.
The seasonal appearance of a long cloud originating over the western flanks of Arsia Mons however does suggest the possibility that these glaciers are shrinking, their ice sublimating into gas each year to form that cloud.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
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4. Donate by check, payable to Robert Zimmerman and mailed to
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You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
Click for original image.
Cool image time! The picture to the right, cropped, reduced, sharpened, and annotated to post here, was taken on January 3, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the eastern wall of what the scientists call a graben, a large depression caused when the ground inside the depression suddenly shifted downward.
The elevation difference between the high and low points is about 3,500 feet. The streaks on the lower half of the cliff wall are slope streaks, a phenomenon unique to Mars that remains at this moment unexplained. Though the streaks resemble avalanches, they do not change the topography in any way, have no debris pile at their base, and appear instead to be a stain that appears at random times of the year that fades with time.
What is intriguing about this picture however is the wavelike floor on its western half. At first glance these waves suggest some form of dust dunes or lava flows, but neither conclusion appears correct. Instead, we are looking at what was one of the first discoveries on Mars of what scientists have determined to be glacial features.
Click for original image.
The green dot in the inset on the overview map to the right marks the location of this picture, on the northwestern flanks of the giant volcano Arsia Mons. The black dots mark the locations of pits — likely skylights into lava tubes — that have been featured as cool images previously. The MRO context camera image above, taken on January 21, 2007 and rotated so north is to the right, provides a full view of the entire graben depression, with those waves of material clearly appearing to flow to the north.
While the waves of material and their location on this giant volcano suggest they might be lava that filled the graben depression, a 2007 science paper using MRO images instead concluded that this material was an aging glacier covered with debris.
After detailed review of new observations, we interpret the fill material on the floor of the large graben at Arsia Mons to be waning stages of debris-covered glaciers that filled the graben in the past. The collections of ridges and furrows on the fill surface suggest that the two alcoves on the southeastern wall of the graben served as the accumulation areas for two large debris-covered glaciers that were the primary source of ice within the graben (Figures 3 and 4). Corresponding patterns of ridges and ridge packets on each of these glaciers (Figure 4) suggest that they formed simultaneously in the two cirque-like alcoves, with the same atmospheric source, and flowed northward along the long axis of the graben.
The paper from which I quote was one of the first that identified what appeared to be glacial features on Mars, here on the western flanks of Arsia Mons. Since then scientists have used MRO to take repeated pictures of the floor of this graben, monitoring it for changes. Unfortunately, the best images easily downloadable on the web do not have the resolution necessary for me to identify any changes, and I have not been able to find any more recent papers studying this graben. Since most of the glaciers on Mars are generally considered inactive, it is likely that this is the situation here as well.
The seasonal appearance of a long cloud originating over the western flanks of Arsia Mons however does suggest the possibility that these glaciers are shrinking, their ice sublimating into gas each year to form that cloud.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
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