NASA Confirms Thousands of Massive, Ancient Volcanic Eruptions on Mars

September 15, 2021

mars arabia terra.jpg
This image shows several craters in Arabia Terra that are filled with layered rock, often exposed in rounded mounds. The image was taken by a camera, the High Resolution Imaging Experiment, on NASA's Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/University of Arizona

Scientists found evidence that a region of northern Mars called Arabia Terra experienced thousands of “super eruptions,” the biggest volcanic eruptions known, over a 500-million-year period.

Some volcanoes can produce eruptions so powerful they release oceans of dust and toxic gases into the air, blocking out sunlight and changing a planet’s climate for decades. By studying the topography and mineral composition of a portion of the Arabia Terra region in northern Mars, scientists recently found evidence for thousands of such eruptions, or “super eruptions,” which are the most violent volcanic explosions known.

Spewing water vapor, carbon dioxide, and sulfur dioxide into the air, these explosions tore through the Martian surface over a 500-million-year period about 4 billion years ago. Scientists reported this estimate in a paper published in the journal Geophysical Research Letters in July 2021.

“Each one of these eruptions would have had a significant climate impact – maybe the released gas made the atmosphere thicker or blocked the Sun and made the atmosphere colder,” said Patrick Whelley, a geologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who led the Arabia Terra analysis. “Modelers of the Martian climate will have some work to do to try to understand the impact of the volcanoes.”After blasting the equivalent of 400 million Olympic-size swimming pools of molten rock and gas through the surface and spreading a thick blanket of ash up to thousands of miles from the eruption site, a volcano of this magnitude collapses into a giant hole called a “caldera.” Calderas, which also exist on Earth, can be dozens of miles wide. Seven calderas in Arabia Terra were the first giveaways that the region may once have hosted volcanoes capable of super eruptions.

Once thought to be depressions left by asteroid impacts to the Martian surface billions of years ago, scientists first proposed in a 2013 study that these basins were volcanic calderas. They noticed that they weren’t perfectly round like craters, and they had some signs of collapse, such as very deep floors and benches of rock near the walls.

“We read that paper and were interested in following up, but instead of looking for volcanoes themselves, we looked for the ash, because you can’t hide that evidence,” Whelley said.

Whelley and his colleagues got the idea to look for evidence of ash after meeting Alexandra Matiella Novak, a volcanologist at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland. Matiella Novak already had been using data from NASA’s Mars Reconnaissance Orbiter to find ash elsewhere on Mars, so she partnered with Whelley and his team to look specifically in Arabia Terra.

The team’s analysis followed up on the work of other scientists who earlier suggested that the minerals on the surface of Arabia Terra were volcanic in origin. Another research group, upon learning that the Arabia Terra basins could be calderas, had calculated where ash from possible super eruptions in that region would have settled: traveling downwind, to the east, it would thin out away from the center of the volcanoes, or in this case, what’s left of them – the calderas.

“So we picked it up at that point and said, ‘OK, well, these are minerals that are associated with altered volcanic ash, which has already been documented, so now we’re going to look at how the minerals are distributed to see if they follow the pattern we would expect to see from super eruptions,” Matiella Novak said.

The team used images from MRO’s (Mars Reconnaissance Orbiter) Compact Reconnaissance Imaging Spectrometer for Mars to identify the minerals in the surface. Looking in the walls of canyons and craters from hundreds to thousands of miles from the calderas, where the ash would have been carried by wind, they identified volcanic minerals turned to clay by water, including montmorillonite, imogolite, and allophane. Then, using images from MRO cameras, the team made three-dimensional topographic maps of Arabia Terra. By laying the mineral data over the topographic maps of the canyons and craters analyzed, the researchers could see in the mineral-rich deposits that the layers of ash were very well preserved – instead of getting jumbled by winds and water, the ash was layered in the same way it would have been when it was fresh.

“That’s when I realized this isn’t a fluke, this is a real signal,” said Jacob Richardson, a geologist at NASA Goddard who worked with Whelley and Novak. “We’re actually seeing what was predicted and that was the most exciting moment for me.”

The same scientists who originally identified the calderas in 2013 also calculated how much material would have exploded from the volcanoes, based on the volume of each caldera. This information allowed Whelley and his colleagues to calculate the number of eruptions needed to produce the thickness of ash they found. It turned out there were thousands of eruptions, Whelley said.

One remaining question is how a planet can have only one type of volcano littering a region. On Earth volcanoes capable of super eruptions – the most recent erupted 76,000 years ago in Sumatra, Indonesia – are dispersed around the globe and exist in the same areas as other volcano types. Mars, too, has many other types of volcanoes, including the biggest volcano in the solar system, called Olympus Mons. Olympus Mons is 100 times larger by volume than Earth’s largest volcano of Mauna Loa in Hawaii, and is known as a “shield volcano,” which drains lava down a gently sloping mountain. Arabia Terra so far has the only evidence of explosive volcanoes on Mars.

It’s possible that super-eruptive volcanoes were concentrated in regions on Earth but have been eroded physically and chemically or moved around the globe as continents shifted due to plate tectonics. These types of explosive volcanoes also could exist in regions of Jupiter’s moon Io or could have been clustered on Venus. Whatever the case may be, Richardson hopes Arabia Terra will teach scientists something new about geological processes that help shape planets and moons.

“People are going to read our paper and go, ‘How? How could Mars do that? How can such a tiny planet melt enough rock to power thousands of super eruptions in one location?’” he said. “I hope these questions bring about a lot of other research.

News Media Contact
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.

Written by Lonnie Shekhtman
NASA’s Goddard Space Flight Center, Greenbelt, Md.



We can compare and contrast today's article, above, with that below, from 2011.


Twenty volcanoes have been identified on Mars. There are two major volcanic regions, Elysium and Tharsis. The largest volcano, Olympus Mons, is located in the Tharsis region.


An image of Olympus Mons and a detailed image of the volcanic cone with the ages of the different lava flows (estimated by counting the number of impact craters). The youngest lava flow is estimated to be about 140 million years ago, which scientists estimate was the last time a volcano erupted on Mars while the dinosaurs were still roaming our planet.

Olympus Mons sits on the same volcanic “bulge” as the three volcanoes of Tharsis Montes — Ascraeus Mons, Pavonis Mons, and Arsia Mons.

When the four mega-volcanoes formed so close together it proved to be more weight than Mars’ surface could bear. The volcanoes made the planet tip over a bit. Some 3 billion years ago, Mars’ outer layers slipped under their weight. The crust and mantle traveled moved an estimated 20 degrees, moving from the polar regions toward the equator. It was enough to change the course of rivers and to dramatically alter the planet’s climate.

Olympus Mons is a shield volcano, which means it oozed huge amounts of lava, rather than simply blowing its top in a catastrophic eruption. Earth’s biggest volcanoes are also shield volcanoes. This lets them grow slowly over time. Unlike Olympus Mons, Arabia Terra appears to possess the only evidence of being an explosive volcano..

However, Earth’s plate tectonics also spread magma out, which keeps terrestrial volcanoes from indefinitely growing taller. Mars, on the other hand, is too small a planet for plate tectonics.

Olympus Mons is some 3.5 billion years old, which means the volcano formed relatively early in Mars’ history. Astronomers suspect, see article above, Olympus Mons could have stayed volcanically active for some 500 million years. That’s much longer than any volcano on Earth remains active.


See: See:

Today Olympus Mons is a dormant shield volcano on Mars and is the largest volcano in the Solar System. Located in the Tharsis region of Mars, along with three other large volcanoes, Olympus Mons measures an incredible 27 km in height, which is 3 times taller than Mount Everest. The mountain was formed from a single hotspot that flowed for an estimated 500 million years. The absence of plate tectonics, which allowed this unimpinged flow, also prevented the massive back pressure that would have blown the top off of the volcano, which would have lowered its overall height.

In the northern part of the Tharsis volcanic province we find Alba Mons, also known as Alba Patera. It is a very unique volcanic structure for several reasons. The volcano features unnaturally low slopes formed by numerous and extensive lava flows and it features a double caldera with the central figure being up to 1.5 km high. Alba Mons, and it's widespread and extensive flows, makes this one of the largest volcanoes in the Solar System by area. Some scientists point to the volcano’s unique location, the antipodal opposite on Mars surface, to the Hellas impact basin as a possible reason its formation and continuation. Seismic waves from the impact may have traveled through the planet causing a weakening of the crust at the point of origin for Alba Mons, much like a contra coup injury to the brain which leaves a bruise on the brain on the opposite side from the initial injury.

Arabia Mons, like Mount Vesuvius which buried Pompeii and Herculaneum*, or the catastrophic eruption of Thera in the Aegean Sea which destroyed the island of Santorini, buried and preserved the city of Akrotiri **. was an explosive volcano on Mars.

It is interesting to note the increased current scientific curiosity concerning Mars, keeping in step with a similar inquisitiveness evinced over Venus and Jupiter. Then to imagine Olympus Mons belching emissions for 500 million years, throughout much of the reign of dinosaurs, as it slowly builds the largest volcanic structure in the Solar System while altering the climate and topography of Mars in the process is quite something. I wonder if these eruptions were visible from our planet? I guess we'll never know.


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Nov 27, 2019
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I love reading the geology in this post. It makes me wonder about the solar system when it was brand new. It was one hot on-fire metal (and other elements) conglomeration at one time. I can almost picture the flying debris, all rotating and cooling, etc. I love imagining what all of that looked like early on.
Jul 29, 2021
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This is my opinion.
The world of science and technology is vast but still tight area and 'information field'. Centuries ago a discovery of archaeology, astronomy, physics, technology, works of philosophers and physics was often a stand alone discovery.
Today, looking through the intertwined scientific fields synchronous discoveries and inspections is not a surprise.
Information sharing, patterns and unbelievable volume of what we have now in exploration, science and technology make them synchronized and more effective with that.
We are closer together in thoughts and deeds as never before, that's why volcanoes are in the spot for several planets at the same time.
And one more thing, this what makes more understanding of the Earth as a part of the Solar system in detail, not separating 'here' and 'somewhere in space'.
Though many thing we definitely won't know for sure, we can picture them quite precisely :)
Unlike the volcanoes on Earth, which move due to the underlying tectonic plates, volcanoes on Mars are stationary because there is no plate motion and subduction zones.

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Because Mars has no underlying plate tectonics, its volcanoes are stationary. However, Martian volcanoes are similar to earth's in respect to their ratios of height and base radius, see above. It is an interesting comparison between the two planets' distinctly different vulcanism.
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