The southernmost extent of Mars’ youngest lava flood event
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 24, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
Labeled “flow margin in Elysium Planitia,” it shows the very edge of what scientists believe was the most recent large lava event on Mars, dubbed the Athabasca Valles, that is thought to have occurred only 600 million years ago. In only a matter of weeks the fast flowing lava covered a region about the size of Great Britain. What we see here is the southernmost edge of that flow, with the smooth terrain on the west an older lava flood plain, covered by the new flood lava from Athabasca on the east.
The polygon cracks likely indicate cracks that formed during the hardening process (like the polygon cracks in drying mud). Hot lava then pushed up from below to form the ridges. It is also possible the ridges are what scientists call “wrinkle ridges,” formed when material shrinks during the drying process.
The white dot on the overview map to the right marks the location, with the white rectangle in the inset indicating the area covered by the picture above. That inset, created from a global mosaic of MRO’s context camera images, makes the flow margin very evident, flowing past a small hill and some ridges before ending to the south.
Athabasca might be the youngest known lava flow on Mars, but in this region between the giant Martian volcanoes the surface is covered for thousands of miles with many such flood lavas, each layer signaling a past eruption. Some of that lava came down from the big volcanoes, travelling many many hundreds of miles. Others erupted out of nearer vents, such as Athabasca, which spewed from a point near the western end of the Cerberus Fossae cracks and ran west and south from there.
In all cases the lava flowed fast, because in Mars’ lower gravity it acts more like water.
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Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on August 24, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
Labeled “flow margin in Elysium Planitia,” it shows the very edge of what scientists believe was the most recent large lava event on Mars, dubbed the Athabasca Valles, that is thought to have occurred only 600 million years ago. In only a matter of weeks the fast flowing lava covered a region about the size of Great Britain. What we see here is the southernmost edge of that flow, with the smooth terrain on the west an older lava flood plain, covered by the new flood lava from Athabasca on the east.
The polygon cracks likely indicate cracks that formed during the hardening process (like the polygon cracks in drying mud). Hot lava then pushed up from below to form the ridges. It is also possible the ridges are what scientists call “wrinkle ridges,” formed when material shrinks during the drying process.
The white dot on the overview map to the right marks the location, with the white rectangle in the inset indicating the area covered by the picture above. That inset, created from a global mosaic of MRO’s context camera images, makes the flow margin very evident, flowing past a small hill and some ridges before ending to the south.
Athabasca might be the youngest known lava flow on Mars, but in this region between the giant Martian volcanoes the surface is covered for thousands of miles with many such flood lavas, each layer signaling a past eruption. Some of that lava came down from the big volcanoes, travelling many many hundreds of miles. Others erupted out of nearer vents, such as Athabasca, which spewed from a point near the western end of the Cerberus Fossae cracks and ran west and south from there.
In all cases the lava flowed fast, because in Mars’ lower gravity it acts more like water.
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.
Darn youngsters,
Always hogging the news.