The eroding north wall of glacial-filled Harmakhis Valles
Click for original image.
Cool image time! The picture to the right, cropped and reduced to post here, was taken on February 8, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
We are looking at the 2,400-foot-high cliff, its lower walls clearly cracking horizontally as they sag downward, with other large sections higher up appearing to have been eroded away in larger pieces.
Yet, the ground below this cliff wall appears to have no debris piles, the kind you would expect below a landslide. Instead, that ground appears to be very glacial in nature, with many linear parallel lines suggesting layers.
The overview map below provides us the context, and an explanation as to where that debris has gone.
The red dot on the overview map near the middle of Harmakhis Valles marks this location, the north wall of that meandering canyon. The canyon itself has been shown with numerous orbital pictures to be filled with a glacier flowing downhill into Hellas Basin.
At 39 degrees south latitude, this cliff is right in the middle of the mid-latitude bands where many glacial features are found on Mars, so it is not surprising that the canyon is glacial filled. A March 19, 2011 MRO context camera picture of this location, showing the entire canyon, makes very clear that glacier. It resembles remarkably many similar glaciers on Earth, such as the Concordia glacier in the Himalayas below the world’s second highest peak, K2.
So, that debris might have fallen from the cliff wall, but it landed on a glacier that, while not appearing active now, at one point in the past was flowing downhill. Over time that glacier carried that debris away.
Readers!
My annual February birthday fund-raising drive for Behind the Black is now over. Thank you to everyone who donated or subscribed. While not a record-setter, the donations were more than sufficient and slightly above average.
As I have said many times before, I can’t express what it means to me to get such support, especially as no one is required to pay anything to read my work. Thank you all again!
For those readers who like my work here at Behind the Black and haven't contributed so far, please consider donating or subscribing. My analysis of space, politics, and culture, taken from the perspective of an historian, is almost always on the money and ahead of the game. For example, in 2020 I correctly predicted that the COVID 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. Every one of those 2020 conclusions has turned out right.
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
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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 and reduced to post here, was taken on February 8, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
We are looking at the 2,400-foot-high cliff, its lower walls clearly cracking horizontally as they sag downward, with other large sections higher up appearing to have been eroded away in larger pieces.
Yet, the ground below this cliff wall appears to have no debris piles, the kind you would expect below a landslide. Instead, that ground appears to be very glacial in nature, with many linear parallel lines suggesting layers.
The overview map below provides us the context, and an explanation as to where that debris has gone.
The red dot on the overview map near the middle of Harmakhis Valles marks this location, the north wall of that meandering canyon. The canyon itself has been shown with numerous orbital pictures to be filled with a glacier flowing downhill into Hellas Basin.
At 39 degrees south latitude, this cliff is right in the middle of the mid-latitude bands where many glacial features are found on Mars, so it is not surprising that the canyon is glacial filled. A March 19, 2011 MRO context camera picture of this location, showing the entire canyon, makes very clear that glacier. It resembles remarkably many similar glaciers on Earth, such as the Concordia glacier in the Himalayas below the world’s second highest peak, K2.
So, that debris might have fallen from the cliff wall, but it landed on a glacier that, while not appearing active now, at one point in the past was flowing downhill. Over time that glacier carried that debris away.
Readers!
My annual February birthday fund-raising drive for Behind the Black is now over. Thank you to everyone who donated or subscribed. While not a record-setter, the donations were more than sufficient and slightly above average.
As I have said many times before, I can’t express what it means to me to get such support, especially as no one is required to pay anything to read my work. Thank you all again!
For those readers who like my work here at Behind the Black and haven't contributed so far, please consider donating or subscribing. My analysis of space, politics, and culture, taken from the perspective of an historian, is almost always on the money and ahead of the game. For example, in 2020 I correctly predicted that the COVID 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. Every one of those 2020 conclusions has turned out right.
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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