Mars was once home to seas and oceans, and perhaps even life. But our neighboring world has long since dried up and its atmosphere has been blown away, while most activity beneath its surface has long ceased. It’s a dead planet.
Or is it?
Previous research has hinted at volcanic eruptions on Mars 2.5 million years ago. But a new paper suggests an eruption occurred as recently as 53,000 years ago in a region called Cerberus Fossae, which would be the youngest known volcanic eruption on Mars. That drives home the prospect that beneath its rusty surface pocked with gigantic volcanoes that have gone silent, some volcanism still erupts to the surface at rare intervals.
“If this deposit is of volcanic origin then the Cerberus Fossae region may not be extinct and Mars may still be volcanically active today,” scientists at the University of Arizona and Smithsonian Institution, write in their paper — which was posted online ahead of peer review and has been submitted to the journal Icarus.
The site of the potential eruption, seen in images from Martian orbit, is near a large volcano called Elysium Mons. It is about 1,000 miles east of NASA’s stationary InSight lander, which touched down on Mars in 2018 to study tectonic activity on the red planet. Appearing like a crack in the surface, the feature looks like a recent fissure eruption, where subsurface volcanic activity has caused superheated volcanic ash and dust to burst through the surface. It is similar to deposits caused by pyroclastic eruptions that scientists have spotted on the moon, Mercury and Earth.
Originating from magma deep beneath the surface, the eruption would have reached a height of several miles before falling back to the ground. The amount of material is estimated at 100 times less than the eruption of Mount St. Helens in 1980, said Steven Anderson, an earth sciences professor at the University of Northern Colorado in Greeley, who was not involved in the paper.
It is the presence of darker material here, coupled with its symmetrical appearance around the fissure, that hints at an eruption. Known as a fault scarp, this type of feature is “very common in Hawaii” as magma near volcanoes causes the surface to expand and crack, says Robert Craddock from the Smithsonian Institution, a co-author on the paper.
By counting the number of craters visible around the feature and in the deposit itself, which is roughly six miles across, the team date the potential eruption ranging from 53,000 to 210,000 years ago. This would by far be the youngest known volcanic eruption on Mars.
“I think it’s pretty compelling,” Dr. Anderson said.
If it holds up to scrutiny, the discovery would have large implications for Mars. In geological terms, 53,000 years is the blink of an eye, suggesting Mars might well still be volcanically active now. It could also have big implications for the search for life on Mars.
Such volcanic activity could melt subsurface ice, providing a potential habitable environment for living things.
“To have life, you need energy, carbon, water and nutrients,” Dr. Anderson said. “And a volcanic system provides all of those.”
NASA’s InSight lander may have already recorded activity linked to this site. Using a seismometer, it has measured hundreds of “marsquakes” or vibrations in the Martian surface. But only two of these have been localized — and both came from Cerberus Fossae.
“It is certainly plausible that the tectonic activity is related to volcanic activity,” said Suzanne Smrekar from NASA’s Jet Propulsion Laboratory, who is the deputy principal investigator on the InSight mission.
It might be possible for InSight to look for more such activity soon.
“It is an exciting paper,” Dr. Smrekar said. “Understanding the present day activity on Mars is indeed a mystery and key to investigating its evolution and habitability.”
Augmented Reality: Explore InSight, NASA’s Latest Mission to Mars
The InSight spacecraft is heading to Mars to listen for marsquakes and study the planet’s structure.
Questions still remain, however. Lu Pan, a planetary scientist from the University of Copenhagen in Denmark, isn’t so sure about the team’s dating method.
“If you want to date a very recent surface, you rely on the population of small impact craters,” Dr. Pan said. “And we have yet to build this large database of small impact craters.”
Even in a conservative scenario, however, David Horvath of the University of Arizona, the paper’s lead author, said the eruption would have been only a million years ago. That alone would breathe new life into our understanding of Mars.
“It definitely leaves open the possibility that, deep in the surface, it may be active today,” he said.
Source: Read Full Article