Giant, Explosive Volcanoes Discovered On Mars

For a long time, scientists have known that the Martian surface was modified by volcanoes that were active billions of years ago. But a new study suggests that some ancient volcanoes were more violent than we once thought.

Researchers from the Natural Museum of History, London, and NASA have found evidence that the Red Planet was once home to giant, explosive volcanoes known as supervolcanoes, changing our understanding of how the atmosphere and sediments were formed on early Mars.

The findings were reported on Wednesday, Oct. 2, in the journal Nature.

The discovery is explained in a Nature Video. We’ve pulled out the highlights.

We know that Mars is covered with craters, cracks, and mounds.

These were formed by impacts from space, erosion, and volcanoes.

A volcano is a crack in a planet's crust, from which lava, ash, rock, and gases erupt.

A supervolcano refers to an extremely large, explosive volcano that produces more than 1,000 cubic kilometers of volcanic material during an eruption.

That's 1,000 times larger than the eruption of Mount St. Helens in 1980, which ejected just 1 cubic kilometer of material.

Although many volcanoes build a mountain of lava around the volcano vent, supervolcanoes are different because of the size of the eruption.

Supervolcanoes eject so much material that the volcano collapses in on itself, forming a bowl-shaped depression known as a caldera. For example, a supervolcano beneath Yellowstone National Park created a large caldera when it erupted 640,000 years ago.

In the study, scientists focused on an ancient, cratered region of Mars known as Arabia Terra.

Arabia Terra contains deposits of layered materials that could have come from volcanoes that exploded, but until now, scientists have been unable to find visual evidence of these supervolcanoes in the region.

The researchers focused on several irregularly-shaped craters located within Arabia Terra.

Like calderas on Earth, these craters appeared to be formed by supervolcanoes -- through massive explosive eruptions followed by a collapse.

One crater in particular, Eden Patera, displayed strong evidence that it was formed by a supervolcano and not an impact from a meteorite or other space material.

That's because Eden Patera (left) lacked the defining features of an impact crater (right), like a raised rim, central mound, or a ring of ejecta, outlined in red by three consecutive rings.

On Earth, calderas are usually surrounded by huge mounds of material that explode from the volcano vent.

Scientists don't see those giant mounds around Eden Patera, meaning the supervolcano must have exploded with such a force that it hurled billions of tons of material far from the source.

That material could have spread around the entire planet.

The supervolcanoes in Arabia Terra may even be the source of fine-grained deposits seen by NASA rovers at the Meridiani Planum and Gale crater landing sites

The discovery of supervolcanic structures changes our understanding of ancient Mars, including how the atmosphere formed from volcanic gases and how sediments formed from volcanic ash.

This is the first time supervolcanoes have been recognised on Mars.

Supervolcanoes are just one example of Mars' harsh environment.

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