Terraced mesas in Martian crater
Click for full resolution image.
The cool image to the right, reduced and annotated to post here, was a captioned photo released by the Mars Reconnaissance Orbiter (MRO) science team earlier this week. Taken by MRO’s high resolution camera, it shows in color a beautifully stair-stepped mesa located in an unnamed 22-mile-wide equatorial crater in Arabia Terra, the large transitional zone between the lowland northern plains and the southern cratered highlands. As the caption notes,
Several craters in Arabia Terra are filled with layered rock, often exposed in rounded mounds. The bright layers are roughly the same thickness, giving a stair-step appearance. The process that formed these sedimentary rocks is not yet well understood. They could have formed from sand or volcanic ash that was blown into the crater, or in water if the crater hosted a lake.
If volcanic ash, the layers are signalling a series of equal eruptions of equal duration, which seems unlikely. Water is also puzzling because of the equatorial location. Like yesterday’s mystery cool image, water is only likely here at a time when the red planet’s rotational tilt, its obliquity, was much higher, placing this at a higher latitude than it is today.
Regardless, make sure you look at the full image here. This crater floor is chock-full of more such terraced mesas, some of which are even more striking than the sample above.
I have also posted below the MRO context camera photo of the entire crater.
Click for full image.
The white box indicates the location of the mesas above.
To my eye, the floor of this crater suggests that it was once water- or ice-filled, with the low point and last area where water/ice existed the crater’s northwest quadrant. The areas to the east and south would have experienced I think repeated exposures and then burials by that water/ice as that material slowly sublimated away over many cycles of slow retreat. It was this repeated process that would have created the stair-stepped terraces.
In a sense, we might be looking at the final product of a crater that was once glacier-filled (like the many found today in the Martian mid-latitudes) but now devoid of any H2O.
The dark streaks by the way are wind-blown sand ponds and dunes, as shown in this high resolution MRO image. Apparently the sand is being piled up against cliff faces and along what appear to be now dry drainage paths, following the grade downward to the crater floor’s low point in the northwest quadrant.
Readers!
Every February I run a fund-raising drive during my birthday month. This year I celebrate my 72nd birthday, and hope and plan to continue writing and posting on Behind the Black for as long as I am able.
I hope my readers will support this effort. As I did in my November fund-raising drive, I am offering autographed copies of my books for large donations. Donate $250 and you can have a choice of the hardback of either Genesis: the Story of Apollo 8 or Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space. Donate $200 and you can get an autographed paperback copy of either.
Please consider supporting my work here at Behind the Black. 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 full resolution image.
The cool image to the right, reduced and annotated to post here, was a captioned photo released by the Mars Reconnaissance Orbiter (MRO) science team earlier this week. Taken by MRO’s high resolution camera, it shows in color a beautifully stair-stepped mesa located in an unnamed 22-mile-wide equatorial crater in Arabia Terra, the large transitional zone between the lowland northern plains and the southern cratered highlands. As the caption notes,
Several craters in Arabia Terra are filled with layered rock, often exposed in rounded mounds. The bright layers are roughly the same thickness, giving a stair-step appearance. The process that formed these sedimentary rocks is not yet well understood. They could have formed from sand or volcanic ash that was blown into the crater, or in water if the crater hosted a lake.
If volcanic ash, the layers are signalling a series of equal eruptions of equal duration, which seems unlikely. Water is also puzzling because of the equatorial location. Like yesterday’s mystery cool image, water is only likely here at a time when the red planet’s rotational tilt, its obliquity, was much higher, placing this at a higher latitude than it is today.
Regardless, make sure you look at the full image here. This crater floor is chock-full of more such terraced mesas, some of which are even more striking than the sample above.
I have also posted below the MRO context camera photo of the entire crater.
Click for full image.
The white box indicates the location of the mesas above.
To my eye, the floor of this crater suggests that it was once water- or ice-filled, with the low point and last area where water/ice existed the crater’s northwest quadrant. The areas to the east and south would have experienced I think repeated exposures and then burials by that water/ice as that material slowly sublimated away over many cycles of slow retreat. It was this repeated process that would have created the stair-stepped terraces.
In a sense, we might be looking at the final product of a crater that was once glacier-filled (like the many found today in the Martian mid-latitudes) but now devoid of any H2O.
The dark streaks by the way are wind-blown sand ponds and dunes, as shown in this high resolution MRO image. Apparently the sand is being piled up against cliff faces and along what appear to be now dry drainage paths, following the grade downward to the crater floor’s low point in the northwest quadrant.
Readers!
Every February I run a fund-raising drive during my birthday month. This year I celebrate my 72nd birthday, and hope and plan to continue writing and posting on Behind the Black for as long as I am able.
I hope my readers will support this effort. As I did in my November fund-raising drive, I am offering autographed copies of my books for large donations. Donate $250 and you can have a choice of the hardback of either Genesis: the Story of Apollo 8 or Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space. Donate $200 and you can get an autographed paperback copy of either.
Please consider supporting my work here at Behind the Black. 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.
Beautiful, some of those dune are miles high, perfect for skiing.
I’m sure some rich person will ship containers full of blue sand for there private resort.
“The healing power of blue crystal sand, all the way from Mars.”
I have not seen any pictures of any territory on Mars ( or any other planet except Earth ) that is as interesting and beautiful ! Why didn’t we send the rover there ? ! This area has to be checked out with a rover ASAP , perhaps a drone of some kind. Somebody make sure Musk sees these pictures ! And President Trump ! ( You could show Biden , but he wouldn’t understand or remember after a few minutes. )
Beautiful yes but it reminds me of looking at PCB board while repairing it under a microscope
Beautiful yes but it reminds me of looking at PCB board while repairing it under a microscope
I love the way the dunes have created fractal patterns, some radiating outward’s from the cone, others developing into a nearly complete circle.
To get a size comparison, the normal dunes which are huge, make a beautiful regular pattern but are microscopic compared to the mountain dunes. All on top of of a fractured bedrock that seems rather smooth.
There are semi circular peaks that surround two of the cones at equal distance. I believe this is evidence that the cones are meteor impacts on something soft that eroded away leaving the melted hardened impact site behind. I see no evidence of volcanic cinder cones, so meteor impact residue is the best explanation. (is my guess)