Giant Mars Volcano Spews Toxic Gas Hinting At Hidden Hot Magma

by Aaron Leong — Thursday, November 05, 2026, 10:53 AM EDT

The white spots may be caused by deposition around vents where magmatic gases may be escaping from Mars' interior — White spots could be deposition around vents where magmatic gases escape from Mars' interior - Image: ESA/TGO/CaSSIS

New data from the European Space Agency's ExoMars Trace Gas Orbiter suggests that Mars might not be entirely geologically dead under the surface after all, pointing instead to a planet that is simply dormant.

Sure, Mars boasts some of the most massive colossal volcanoes in the entire solar system, monsters like Olympus Mons that make Earth’s tallest peaks look like pimples, but the common consensus has been that these fiery behemoths went cold billions of years ago. We figured the planet's core had cooled down, leaving behind a relatively quiet and frozen museum piece.

However, fresh atmospheric data and orbital imagery have zeroed in on Alba Mons, a shield volcano situated in the Mars' northern hemisphere, where scientists have noticed strange, localized spikes of hydrogen chloride gas. On Earth, HCl is the standard calling card of active magmatic vents that escape from hot churning rock deep beneath the crust.

Even though much of the atmospheric gas on Mars fluctuates predictably with shifting seasons and global dust storms, these specific HCl plumes didn't follow the usual script. Instead, they kept popping up in a very specific place and during an odd time of the Martian year, right above a network of newly highlighted fissures slicing across the flanks of Alba Mons.

The northern flanks of the Alba Mons volcano on Mars in wider context - Image: MEX/HRSC/ESA/DLR/FU Berlin, G. Michael

Pinpointing these micro-signatures from orbit was no easy feat either. Co-lead author Daniel Mège, a professor at the Space Research Centre of the Polish Academy of Sciences, described the amount of effort in teasing out the truth from complex data sets. “The Trace Gas Orbiter was able to find the smoking gun. It was like looking for a needle in a haystack,” Mège explained, stressing the sheer challenge of spotting a handful of gas molecules while zipping through space. He added, “Our findings suggest that Mars has retained enough internal heat to support volcanic activity until recently and possibly still does.”

If hot magma is indeed lurking close enough to the surface to leak gas through fractures, it could no doubt shift how we view the red planet's modern geology. It means Mars still harbors pockets of residual internal warmth.

Even more exciting is what this means for the search for past or present life. Where there is volcanic heat, there is the potential for geothermal activity, hydrothermal systems, and melted subsurface ice. As Mège pointed out, “Looking for Martian life in the seeping fissures of the Alba Mons region would make a lot of sense. If hydrothermal systems are active, they could contain the niches we are looking for.”