Evidence of recent volcanic activity on Mars shows eruptions may have taken place in the past 50,000 years, according to a new study by researchers at the University of Arizona’s Lunar and Planetary Laboratory and Planetary Science Institute.
Most of the volcanism on the Red Planet occurred 3-4 billion years ago, with smaller eruptions in isolated places continuing perhaps 3 million years ago. But, until now, there was no evidence that Mars could still be volcanically active.
Using data from satellites orbiting Mars, the researchers discovered a previously unknown volcanic deposit. They detail their findings in the article “Evidence of a geologically recent explosive volcanism at Elysium Planitia, Mars”, published in the journal Icarus.
“It is possibly the youngest volcanic deposit ever documented on Mars,” said lead study author David Horvath, who did the research as a postdoctoral researcher at UArizona and is now a Planetary researcher. Science Institute. “If we were to compress the geological history of Mars into a single day, it would have happened in the very last second.”
The volcanic eruption produced a smooth, dark, 8-mile-wide deposit surrounding a 20-mile-long volcanic fissure.
“When we first noticed this deposit, we knew it was something special,” said study co-author Jeff Andrews-Hanna, associate professor at the UArizona Lunar and Planetary Laboratory and lead author. of the study. “The deposit was unlike anything else found in the region, or even on all of Mars, and more closely resembled features created by ancient volcanic eruptions on the Moon and Mercury.”
Further investigation showed that the material’s properties, composition and distribution are what one would expect for a pyroclastic eruption – an explosive eruption of magma driven by expanding gases, much like the opening. of a shaken soda can.
The majority of volcanism in the Elysee Planitia area and elsewhere on Mars consists of lava flowing on the surface, similar to recent eruptions in Iceland studied by co-author Christopher Hamilton, Arizona associate professor of science lunar and planetary. While there are many examples of explosive volcanism on Mars, they happened a long time ago. However, this repository looks different.
“This feature covers the surrounding lava flows and appears to be a relatively cool, thin deposit of ash and rock, representing a different eruption style than previously identified pyroclastic features,” Horvath said. “This eruption could have spewed ash up to 6 miles into Mars’ atmosphere. It is possible that these types of deposits are more common but have been eroded or buried.”
The site of the recent eruption is about 1,600 kilometers from NASA’s InSight lander, which has been studying seismic activity on Mars since 2018. Two earthquakes, the Martian equivalent of earthquakes, have been discovered in the region around the Cerberus Fossae, and recent work has suggested the possibility that these could be due to the movement of magma deep underground.
“The young age of this deposit absolutely raises the possibility that there could still be volcanic activity on Mars, and it is intriguing that the recent earthquakes detected by the InSight mission originate from the Cerberus Fossae,” Horvath said. In fact, the research team predicted it would be a likely location for earthquakes several months before NASA’s InSight lander landed on Mars.
A volcanic deposit like this also raises the possibility of habitable conditions below the surface of Mars in recent history, Horvath said.
“The interaction of the ascending magma and the icy substrate of this region could have provided favorable conditions for microbial life quite recently and raises the possibility of an existing life in this region,” he said.
Similar volcanic cracks in this region were the source of huge flooding, possibly 20 million years ago, when groundwater burst onto the surface.
Andrews-Hanna’s research group continues to investigate the causes of the rash. Pranabendu Moitra, a researcher in the Arizona Department of Geosciences, probed the mechanism behind the eruption.
An expert in similar explosive eruptions on Earth, Moitra developed models to examine the possible cause of the Martian eruption. In a forthcoming article in the journal Earth and Planetary Science Letters, he suggests that the explosion could have been the result of gases already present in the Martian magma, or that it could have occurred when the magma came in contact with Martian permafrost.
“The ice melts into water, mixes with the magma and vaporizes, forcing a violent explosion of the mixture,” Moitra said. “When water mixes with magma, it’s like pouring gasoline on a fire.”
He also points out that the youngest volcanic eruption on Mars occurred just 10 kilometers from the planet’s youngest high-impact crater – a 6-mile-wide crater named Zunil.
“The ages of the eruption and the impact are indistinguishable, raising the possibility, even speculative, that the impact actually triggered the volcanic eruption,” Moitra said.
Several studies have found evidence that large earthquakes on Earth can cause an eruption of magma stored below the surface. The impact that formed the Zunil crater on Mars would have rocked the Red Planet like an earthquake, Moitra explained.
While the most spectacular giant volcanoes elsewhere on Mars – such as Olympus Mons, the highest mountain in the solar system – tell a story of the ancient dynamics of the planet, the current hotspot of Martian activity appears to be in the plains relatively devoid of solar system features. the Elysée region of the planet.
Andrews-Hanna said it was remarkable that an area hosts the epicenters of current earthquakes, the most recent flooding, the most recent lava flows and now an even more recent explosive volcanic eruption.
“This may be the most recent volcanic eruption on Mars,” he said, “but I think we can be sure it won’t be the last.”
The volcanic deposit described in this study, along with the ongoing seismic rumble inside the planet detected by InSight and possible evidence of methane plume releases to the atmosphere detected by NASA’s MAVEN orbiter, suggest that Mars is far from a cold and inactive world, Andrews -Hanna said.
“All of this data seems to tell the same story,” he said. “Mars is not dead.”