New spacecraft observations from Mars indicate that the Red Planet is not geologically dead deep inside, but rather possesses enough internal heat to maintain dormant volcanic activity. Researchers studying volcanic fissures along the Alba Mons region detected hydrogen chloride gas escaping to the surface, pointing to the existence of a subterranean magma chamber.
Gas Seepage from Alba Mons Fissures
The European Space Agency mission ExoMars Trace Gas Orbiter originally reported traces of hydrogen chloride gas in the Martian atmosphere in 2021. While this compound typically escapes from magmatic vents on Earth, its presence on Mars followed an unexpected seasonal pattern. The gas normally reaches peak levels in the northern hemisphere during winter and largely disappears in the summer due to local dust and water cycles.
However, researchers noticed an exception to this rule in early summer above volcanic fissures on the flanks of Alba Mons, located in the planet’s Tharsis region. The Alba Mons area is the largest volcano on Mars in terms of surface area, sharing the same regional expanse as Olympus Mons, the tallest volcano in the solar system. Using the orbiter’s CaSSIS camera, scientists identified fresh, narrow fissures measuring hundreds of metres long in the Alba Mons region, accompanied by surface colour changes.
The research team theorizes that magmatic gases rise through these internal rifts from a dormant magma chamber. During the freezing Martian winter, falling temperatures down to -120°C cause ice to block the fissures, trapping the gases below. When that ice directly sublimates into gas during the early summer months, the trapped compounds are released, creating the localized hydrogen chloride spikes detected by the orbiter.
Linking Martian Gas Seeps to Volcanic Origins
Pinpointing the volcanic origin of the gas required extensive cross-disciplinary analysis of atmospheric and geological data. Daniel Mège, a scientist at the Space Research Centre of the Polish Academy of Sciences, noted the immediate geological implications upon reviewing the spatial distribution of the seeping gas.
Looking at the spatial distribution of the seeping, it became instantly obvious to me that there was something volcanic behind it, but it had to be demonstrated
Daniel Mège, Space Research Centre of the Polish Academy of Sciences
Verifying the finding required ruling out alternative explanations for the atmospheric data. According to Mège, evaluating chemical processes in the Martian atmosphere formed a major component of the investigation.
A huge part of the work consisted of examining all the possible chemical processes going on in the Martian atmosphere.
Daniel Mège, Space Research Centre of the Polish Academy of Sciences
The findings were published on November 4, 2026, in the journal Science Advances. Researchers involved in the study emphasize that the data demonstrate the planet’s capacity to retain internal heat over geological timescales. An international research team led by Alexander Trokhimovskiy notes that the release of hydrogen chloride comes from hot magma beneath the surface.
Implications for Habitable Niches
The discovery of active magmatic venting opens new avenues in the search for potential past or present microbial life on Mars. In the planet’s earlier history, higher concentrations of magmatic gases like hydrogen chloride would have contributed to a thicker atmosphere and a warmer climate capable of supporting liquid water across broad surface areas.
When molten lava forces its way through the Martian crust and encounters subterranean groundwater, it can generate warm hydrothermal systems. On Earth, these environments serve as prime habitats where microorganisms develop and find shelter from harsh surface conditions. Investigators suggest that targeting the seeping fissures in the Alba Mons region could offer similar protected niches for astrobiological exploration, noting that finding such life might require digging a depth ranging from twenty centimeters to one hundred meters.
Earlier coverage: 32 Martian Craters Reveal Seasonal Ice Shifts