Ancient flood lava on the upper slopes of the solar system’s largest volcano
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 13, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
In this one picture can be seen a glimpse of the entire history of the numerous lava eruptions that once dominated Mars when its giant volcanoes were active one to three billion years ago. The three aligned craterlike depressions likely signal the existence of a large lava tube below ground, placed there during an early large eruption, when the volcano was spewing out so much flood lava that such large tubes could form. The smaller meandering surface rills signal later eruptions that carried less flood lava and thus produced a smaller drainage features.
And finally, the rough and cracked appearance of the surface indicates the ancient age of those last eruptions, probably laid down about a billion years ago. Since then, the volcano has been dormant, and the frozen lava here has had time to erode, become roughened, and show signs of slowly wearing away.
The black dot on the overview map to the right marks the location, on the western upper flanks of Olympus Mons, the largest known volcano in the solar system. The caldera is only about 14 miles away, so because we are near the top of the volcano the surface lava at this spot is likely some of the last active lava spewed out. Though it is very old, it is also some of the youngest Olympus Mons’ lava.
Though Olympus Mons is more than twice as high as Mount Everest, the slopes on its flanks are extremely gentle. From high to low the descent here is about 700 feet, across a distance of about three miles. That is not a very steep grade, about 3%, and it continues unchanged at about that angle for many many miles.
One last caveat: The three aligned depressions might be indicating a vent from which lava also poured. Thus, some of the lava at this location might not have come from the volcano’s main caldera, but from an opening at this spot.
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.
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Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 13, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
In this one picture can be seen a glimpse of the entire history of the numerous lava eruptions that once dominated Mars when its giant volcanoes were active one to three billion years ago. The three aligned craterlike depressions likely signal the existence of a large lava tube below ground, placed there during an early large eruption, when the volcano was spewing out so much flood lava that such large tubes could form. The smaller meandering surface rills signal later eruptions that carried less flood lava and thus produced a smaller drainage features.
And finally, the rough and cracked appearance of the surface indicates the ancient age of those last eruptions, probably laid down about a billion years ago. Since then, the volcano has been dormant, and the frozen lava here has had time to erode, become roughened, and show signs of slowly wearing away.
The black dot on the overview map to the right marks the location, on the western upper flanks of Olympus Mons, the largest known volcano in the solar system. The caldera is only about 14 miles away, so because we are near the top of the volcano the surface lava at this spot is likely some of the last active lava spewed out. Though it is very old, it is also some of the youngest Olympus Mons’ lava.
Though Olympus Mons is more than twice as high as Mount Everest, the slopes on its flanks are extremely gentle. From high to low the descent here is about 700 feet, across a distance of about three miles. That is not a very steep grade, about 3%, and it continues unchanged at about that angle for many many miles.
One last caveat: The three aligned depressions might be indicating a vent from which lava also poured. Thus, some of the lava at this location might not have come from the volcano’s main caldera, but from an opening at this spot.
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.
The settling cracks along side the lava tube is evidence that this tube is very large.
A good measure of the slope is the “three pools” which are filled showing the Highwall on the right with the outflow on the left with the floor of the pool being level.
One of the cracks extended through the lower pool showing the volcano still settling. A dark smudge could be an out gassing vent? (there is bound to be many hollow cavities)
One item of note, the top of this volcano is above the Martian atmosphere… What we are seeing has been unaffected by Martian winds giving the lower half of the picture the appearance of lunar regolith. Impact craters big and small cover the surface.
Just came in from watching the annular eclipse, 93% covered in SLC. Wispy clouds parted just in time.
Spectacular as always.