Myriad flows on mountainous inner crater wall on Mars
Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on February 27, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
That the science team labels this “Monitoring Slopes for Changes on Eastern Terraces of Mojave Crater” is quite understandable. The number of apparent dentritic channels suggests strongly the possibility of change over time, which is why MRO has been used repeatedly to monitor this location, beginning in 2006, when the science team noted this in a caption:
Aptly-named Mojave Crater in the Xanthe Terra region has alluvial fans that look remarkably similar to landforms in the Mojave Desert of southeastern California and portions of Nevada and Arizona.
Alluvial fans are fan-shaped deposits of water-transported material (alluvium). They typically form at the base of hills or mountains where there is a marked break, or flattening of slope. They typically deposit big rocks near their mouths (close to the mountains) and smaller rocks at greater distances. Alluvial fans form as a result of heavy desert downpours, typically thundershowers. Because deserts are poorly vegetated, heavy and short-lived downpours create a great deal of erosion and nearby deposition.
There are fans inside and around the outsides of Mojave crater on Mars that perfectly match the morphology of alluvial fans on Earth, with the exception of a few small impact craters dotting this Martian landscape.
The white dot on the overview map to the right marks the location, on the eastern rim of 37-mile-wide Mojave Crater. The inset shows the entire crater, with the white dot marking the area covered by the picture above.
Though such geology on Earth suggest intense but short rain-showers, that is not likely the cause of these features. This location, at the outlet of the Valles Marineris canyon system, is also believed to have been shaped by catastrophic floods, the remnants of which some scientists think left behind a short-lived inland sea.
The present theory for explaining these flows is that the leftover water from this sea impregnated the ground as ice. When the impact occurred that created Mojave Crater it melted that ice, which then flowed to form these channels. Whether there is any ice left in this terrain today is unlikely, as this crater is in the Martian dry tropics, where no near-surface ice is found. It isn’t impossible, however, which is one reason the scientists are monitoring the site for changes.
That’s the theory at least. No one should be surprised if new data, collected on the spot by future Martian colonists, results in a completely different explanation.
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.
Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on February 27, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
That the science team labels this “Monitoring Slopes for Changes on Eastern Terraces of Mojave Crater” is quite understandable. The number of apparent dentritic channels suggests strongly the possibility of change over time, which is why MRO has been used repeatedly to monitor this location, beginning in 2006, when the science team noted this in a caption:
Aptly-named Mojave Crater in the Xanthe Terra region has alluvial fans that look remarkably similar to landforms in the Mojave Desert of southeastern California and portions of Nevada and Arizona.
Alluvial fans are fan-shaped deposits of water-transported material (alluvium). They typically form at the base of hills or mountains where there is a marked break, or flattening of slope. They typically deposit big rocks near their mouths (close to the mountains) and smaller rocks at greater distances. Alluvial fans form as a result of heavy desert downpours, typically thundershowers. Because deserts are poorly vegetated, heavy and short-lived downpours create a great deal of erosion and nearby deposition.
There are fans inside and around the outsides of Mojave crater on Mars that perfectly match the morphology of alluvial fans on Earth, with the exception of a few small impact craters dotting this Martian landscape.
The white dot on the overview map to the right marks the location, on the eastern rim of 37-mile-wide Mojave Crater. The inset shows the entire crater, with the white dot marking the area covered by the picture above.
Though such geology on Earth suggest intense but short rain-showers, that is not likely the cause of these features. This location, at the outlet of the Valles Marineris canyon system, is also believed to have been shaped by catastrophic floods, the remnants of which some scientists think left behind a short-lived inland sea.
The present theory for explaining these flows is that the leftover water from this sea impregnated the ground as ice. When the impact occurred that created Mojave Crater it melted that ice, which then flowed to form these channels. Whether there is any ice left in this terrain today is unlikely, as this crater is in the Martian dry tropics, where no near-surface ice is found. It isn’t impossible, however, which is one reason the scientists are monitoring the site for changes.
That’s the theory at least. No one should be surprised if new data, collected on the spot by future Martian colonists, results in a completely different explanation.
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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