The endless volcanic ash of Mars’ Medusae Fossae Formation
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and enhanced to post here, was taken on January 6, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows a small but typical area of the Medusae Fossae Formation, what is thought to be the largest volcanic ash deposit on Mars.
The picture itself was a “terrain sample,” taken by the MRO science team not as part of any specific research but to fill a gap in the camera’s schedule so as to maintain its temperature. The terrain itself looks like a field of sand that someone had run a fine comb across. In this case, the comb was the winds of Mars, prevailing from the southeast to the northwest. The crescent-like divots in the picture’s lower right are probably caused by some hard underground feature that the winds cannot blow away. Instead, it blows around, like water in rapids flowing around a rock, and takes the ash with it as it does so.
The white dot near the center of the overview map to the right marks this picture’s location, inside Medusae.
Scientists estimate the size of the entire Medusae ash deposit to be comparable to about the size of India and in some places as much as a thousand feet deep. They believe the ash is volcanic pyroclastic ash, material released quickly during a violent volcanic eruption such as the one that occurred at Mount St. Helens in 1980. Nor does all of the deposit have this endless combed look. Because the ash drapes the underlying topography, it sometimes shows hints of those underlying structures. And of course, the edges and gaps in the deposit result in more complex topography. See for example this July 2021 cool image only a few miles to the southwest of today’s picture. This endless plain of ash suddenly ends, as the ground drops down into a canyon.
The mystery is that this formation, while smack dab in the middle of volcano country surrounded by Mars’ biggest volcanoes, it is too far away from those volcanoes for the ash from their eruptions to have been blown here by the wind, based on our present understanding of Mars’ atmosphere. Scientists are therefore unsure how the ash got here. Though much of the terrain here, between these giant volcanoes, is flood lava laid down by nearby vents and not from the big mountainous volcanoes, such flood lava doesn’t produce explosive pyroclastic ash. Instead, this lava flows out from the vents more gently, steadily without explosive events.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the 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. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
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, cropped, reduced, and enhanced to post here, was taken on January 6, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows a small but typical area of the Medusae Fossae Formation, what is thought to be the largest volcanic ash deposit on Mars.
The picture itself was a “terrain sample,” taken by the MRO science team not as part of any specific research but to fill a gap in the camera’s schedule so as to maintain its temperature. The terrain itself looks like a field of sand that someone had run a fine comb across. In this case, the comb was the winds of Mars, prevailing from the southeast to the northwest. The crescent-like divots in the picture’s lower right are probably caused by some hard underground feature that the winds cannot blow away. Instead, it blows around, like water in rapids flowing around a rock, and takes the ash with it as it does so.
The white dot near the center of the overview map to the right marks this picture’s location, inside Medusae.
Scientists estimate the size of the entire Medusae ash deposit to be comparable to about the size of India and in some places as much as a thousand feet deep. They believe the ash is volcanic pyroclastic ash, material released quickly during a violent volcanic eruption such as the one that occurred at Mount St. Helens in 1980. Nor does all of the deposit have this endless combed look. Because the ash drapes the underlying topography, it sometimes shows hints of those underlying structures. And of course, the edges and gaps in the deposit result in more complex topography. See for example this July 2021 cool image only a few miles to the southwest of today’s picture. This endless plain of ash suddenly ends, as the ground drops down into a canyon.
The mystery is that this formation, while smack dab in the middle of volcano country surrounded by Mars’ biggest volcanoes, it is too far away from those volcanoes for the ash from their eruptions to have been blown here by the wind, based on our present understanding of Mars’ atmosphere. Scientists are therefore unsure how the ash got here. Though much of the terrain here, between these giant volcanoes, is flood lava laid down by nearby vents and not from the big mountainous volcanoes, such flood lava doesn’t produce explosive pyroclastic ash. Instead, this lava flows out from the vents more gently, steadily without explosive events.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the 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. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
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.
Martian Volcanos