Our findings suggest that Mars has retained enough internal heat to support volcanic activity until recently, and possibly still does,
Daniel Mège said, according to Space.
The European Space Agency’s ExoMars Trace Gas Orbiter detected hydrogen chloride gas above volcanic fissures on Alba Mons during the cold aphelion season, Universe Today reported.
For decades, researchers assumed Mars was geologically dead once its interior cooled and its geodynamo shut down. The latest data point comes from atmospheric readings gathered by the Trace Gas Orbiter.
Alba Mons is a massive shield volcano in the northern Tharsis region of Mars, stretching further across the surface than Olympus Mons despite standing lower. High-resolution orbital cameras recently revealed narrow fissures less than a meter wide on the volcano’s slopes.
On Earth, volcanoes regularly vent hydrogen chloride from underground magma chambers. Mars normally shows traces of this corrosive gas only during the warm perihelion season as a result of atmospheric dust and water cycles. Finding the gas in cold aphelion over fresh cracks points to a different origin entirely. We needed to be rigorous, critical and creative to explain the presence of hydrogen chloride,
Mège told Space.
The research team calculated gas seepage rates and published their findings in Science Advances on Nov. 4. Their work rules out standard atmospheric aerosols as the source for the aphelion detections, pointing instead to a subsurface volcanic plumbing system. Universe Today reported that the authors view the gas as potential seepage from active magma chambers at depth.
Mège noted to Space that if hydrothermal systems remain active underground, they could theoretically provide the heat and chemical energy needed to support microorganisms.
Alba Mons is a shield volcano located in the northern Tharsis region of Mars. It is the largest volcano on the planet by surface area, with volcanic flows extending more than 1,300 kilometers from its summit.
Hydrogen chloride normally appears in the Martian atmosphere only during perihelion due to seasonal warming and solar interactions with dust and water. Detecting the gas during the cold aphelion season suggests it is leaking from underground sources rather than forming through atmospheric chemistry.
Orbital cameras on the ExoMars Trace Gas Orbiter and NASA’s Mars Reconnaissance Orbiter identified fresh fissures less than a meter wide grouped into belts along topographic ridges.
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