Volcanoes on Mars Trail of a sudden small eruption

Does our neighboring planet still have the remnants of its previous fire? This now points to a discovery: the dark deposition around a fissure in the Martian surface could be the effect of a volcanic eruption that occurred only in the last 53,000 to 210,000 years. InSight has also detected underground seismic activity in the area. So Mars could remain volcanically active, which also increases the possibility of life-friendly conditions underground, the scientists say.

Our neighboring planet was once “hot-blooded” – evidenced by the occasional remnants of giant volcanic cones and rock deposits on its surface. But these volcanic effects are pretty much ancient: Most of the volcanic activity on the Red Planet occurred three to four billion years ago – after which they boiled less and less. It is assumed thus far that small eruptions occurred even about three million years ago. But the current study now points to more recent activities: “It could be the smallest volcanic deposit that has been documented on Mars so far,” says lead author David Horvath of the University of Arizona.

A dark deposit on the horizon

Horvath and colleagues discovered the structure on satellite imagery of the Elysium Planetia region in the Cerberus Fusai fracture zone. It is a dark sediment approximately 13 kilometers wide and encircles an almost 30-kilometer fissure in the Earth’s interior in a strikingly uniform pattern. “When we first noticed this deposit, we knew it was private,” says senior author Jeff Andrews Hana of the University of Arizona. “The sediments were unlike anything that had been discovered in the region or even on Mars entirely until now.” The features indicate that it could be a volcanic eruption effect – an explosion of material propelled by expanding gases, such as the opening of a shaky soda bottle.

“This phenomenon covers the surrounding rock formations and looks like relatively fresh ash deposits and rocks,” Horvath reports. So scientists assume that the cause of this is the eruption of lava. Through so-called stratigraphic analyzes of the surface structures in the region, scientists have also been able to narrow down when deposition occurs. Accordingly, it is likely that it was only between 53,000 and 210,000 years old. “If we had compressed the geological history of Mars into a single day, it would have happened at the last moment,” Horvath says.

Co-author Pranabindo Muitra suggests that the explosion was caused by gases already present in Martian magma or that it occurred when the magma touched the permafrost in the interior of the Martian surface. “The ice melts in the water, mixes with magma and evaporates, causing the mixture to explode violently,” says Muetra. This process could be caused by impact tremors: the impact of the volcanic eruption is located only about ten kilometers from a small crater called Zunil. “Despite speculation, it appears likely that the impact caused the volcanic eruption,” says Muitra.

There is an underground rumble in the area

Another feature of the site in Cerberus Fossae is even more interesting: This region is the focus of discovery by NASA’s InSight probe, which has been investigating seismic activity on Mars since 2018. InSight has detected two earthquakes with foci in the region around Cerberus Fossae. There were already doubts that these earthquakes could be due to the movement of magma underground. The young volcanic impact site seems to fit this one. “The age of these sediments indicates that there may still be volcanic activity on Mars,” Horvath says. “It is surprising that the earthquakes detected by the Insight mission came from Cerberus Fusai.”

As he and his colleagues point out, knowledge about volcanoes on Mars also has a role in assessing the question of whether microbial life could exist underground. “The interaction between the ascending magma and the icy substrate of this region could have created favorable conditions for microbial life relatively recently and thus increases the possibility of life in this area,” Horvath says.

So it seems clear: the exciting region and the most recent trace of a volcanic eruption on Mars will now remain the focus of science.

Source: University of Arizona, Articles: Icarus.2021.114499

11. May 2021

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