Underground Volcanoes May Be Present on Mars

The presence — or absence — of liquid water on Mars has significant implications for humanity: first, it is a crucial element for the red planet’s past habitabltiy, and second, the water, if it is there, may be used by human explorers as a resource. Last year, a study published in the Science journal suggested that liquid water exists under the south polar ice cap on Mars. However, a new study published in the AGU’s Geophysical Research Letters journal makes the argument that an underground heat source is needed for water to exist.

“We think that if there is any life, it likely has to be protected in the subsurface from the radiation,” said Ali Bramson, a postdoctoral research associate at the Lunar and Planetary Laboratory at the University of Arizona and a co-lead author of the new paper. “If there are still magmatic processes active today, maybe they were more common in the recent past, and could supply more widespread basal melting. This could provide a more favorable environment for liquid water and thus, perhaps, life.”

Scientists are interested in the presence of liquid water on Mars because it would be proof that the red planet was once habitable. The new study does not comment on the debate, but instead suggests that a heat source — the formation of a magma chamber — must have existed under the Martian surface to produce liquid water under the ice cap, which measures 1.5 kilometers in thickness. The authors do state that if the magmatic activity had not taken place, the presence of liquid water is unlikely.

“Different people may go different ways with this, and we’re really interested to see how the community reacts to it,” said Michael Sori, an associate staff scientist in the Lunar and Planetary Laboratory at the University of Arizona and a co-lead author of the new paper.

If recent magmatic activity did take place, that means that in terms of geology, Mars is an active planet. This would give scientists more information about the evolution of planets over time.

Last year’s Science study suggested that liquid water could be present under ice sheets, just as it does on Earth. However, on Earth, the heat of the planet causes the ice to melt. The study authors did not specify how the liquid water on Mars came to be. Because Mars has lower temperatures than Earth, it is unclear what would cause the melting.

“We thought there was a lot of room to figure out if [the liquid water] is real, what sort of environment would you need to melt the ice in the first place, what sort of temperatures would you need, what sort of geological process would you need? Because under normal conditions, it should be too cold,” Sori said.

Researchers who published the new study operated under the assumption that the liquid water does exist under the ice cap. They then focused on conditions necessary for the water to exist, including how much heat would need to come from the interior of the planet, and whether there could be enough salt, which lowers the ice’s melting point, at the ice cap base to melt the ice.

The study postulates that volcanic activity in the subsurface of Mars is a plausible explanation. They say that magma could have risen to the planet’s surface approximately 300,000 years ago and pooled right below the surface without breaking it. As it cooled, the heat from it melted the ice, and the magma chamber is still releasing heat, which explains the liquid water present today.

This is not the first time the idea of volcanic activity on Mars has been cited. However, most evidence points to volcanic activity millions of years ago, while the new study suggests that it is much more recent — and possibly still happening today.

“This would imply that there is still active magma chamber formation going on in the interior of Mars today and it is not just a cold, sort of dead place, internally,” Bramson said.

The new paper has added another layer to the existing debate about the presence of liquid water on Mars. However, if more studies agree with the newest model, it will prove to be an important piece of the puzzle.

Photo credit: NASA