NASA confirms thousands of ancient massive volcanic eruptions on Mars

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

By emitting water vapor, carbon dioxide, and sulfur dioxide into the air, these explosions passed through the Martian surface over a period of 500 million years about 4 billion years ago. Scientists reported this estimate in a paper published in the journal Geophysical research letters in July 2021.

“Each of these eruptions would have had a significant climatic impact, perhaps the gas released made the atmosphere thicker or blocked the Sun and made the atmosphere colder,” said Patrick Whelley, a geologist at Goddard Space. NASA Flight Center in Greenbelt, Maryland, who led the Arabia Earth analysis. “Martian climate modelers will have some work to do to try to understand the impact of volcanoes.” After the equivalent of 400 million Olympic-sized pools of molten rock and gas exploded on the surface and spread a thick blanket of ash up to thousands of miles from the site of the eruption, a volcano of this magnitude it sinks into a giant hole called a caldera. Boilers, which also exist on Earth, can be tens of miles wide. Seven boilers on Arabian Earth were the first gifts the region could have hosted from volcanoes capable of super eruptions.

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

“We read this paper and were interested in tracking it, but instead of looking for the volcanoes themselves, we looked for ash because these evidence can’t be hidden,” Whelley said.

Whelley and her colleagues came up with the idea of ​​looking for ash evidence after meeting Alexandra Matiella Novak, a volcanologist at the Johns Hopkins Laboratory of Applied Physics in Laurel, Maryland. Matiella Novak was already using data from NASA’s Mars Reconnaissance Orbiter to find ash elsewhere on Mars, so she teamed up with Whelley and her team to look specifically at Arabia Earth.

The team’s analysis tracked the work of other scientists who previously suggested that the minerals on the surface of Arabian Earth were of volcanic origin. Another research group, learning that the basins of the Arabian Earth could be boilers, had calculated where the ashes of possible super eruptions in this region would have settled: traveling through the wind, towards the this, would be thinned from the center of the volcanoes or in this case, what is left, the boilers.

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

The team used images from the MRO Compact Reconnaissance Image Spectrometer for Mars to identify surface minerals. Looking at the walls of canyons and craters hundreds to thousands of miles from the boilers, where the ash would have been carried by the wind, they identified volcanic minerals turned to clay by water, including montmorillonite, imogolite and al. lofà. Then, using MRO camera images, the team made three-dimensional topographic maps of Arabian Earth. By placing the mineral data on the topographic maps of the analyzed canyons and craters, the researchers were able to see in the mineral-rich deposits that the ash layers were very well preserved; just as it would have been when it was cool.

“That’s when I realized that this wasn’t a coincidence, but a real sign,” said Jacob Richardson, a NASA geologist Goddard who worked with Whelley and Novak. “We’re actually seeing what was expected and that was the most exciting moment for me.”

The same scientists who originally identified the boilers in 2013 also calculated the amount of material that would have exploded from the volcanoes, based on the volume of each boiler. 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 question that remains is how a planet can have only one type of volcano spilling over a region. On Earth, volcanoes capable of super eruptions — the most recent erupted 76,000 years ago in Sumatra, Indonesia — are scattered around the world and exist in the same areas as other types of volcanoes. Mars also has many other types of volcanoes, including the largest volcano in the solar system, called Olympus Mons. Olympus Mons is 100 times larger in volume than Earth’s largest volcano, Mauna Loa, in Hawaii, and is known as the “shield volcano,” which drains lava down a mountain with gentle slopes. Arabia Earth has so far the only evidence of explosive volcanoes on Mars.

Supereruptive volcanoes may have concentrated in regions of the Earth, but have physically and chemically eroded or moved around the planet as continents have shifted due to plate tectonics. Such explosive volcanoes could also exist in regions of the moon Io of Jupiter or could have been clustered on Venus. Whatever the case, Richardson hopes Arabia Earth will teach scientists something new about geological processes that help shape planets and moons.

“People will read our newspaper and say,‘ How? How could Mars do that? How can such a small planet melt enough rock to feed thousands of super eruptions in one place? “, He said.” I hope these questions provide much more research.