Scientists have long known that Mars holds plenty of ice, but most of it is thought to be near the planet’s poles. So when spacecraft began detecting signs of hydrogen—often a clue that ice may lie just below the surface—near the Martian equator, researchers were puzzled. How could ice exist in one of the hottest and driest parts of the planet?
A new study published in *Nature Communications* offers a surprising answer: ancient volcanic eruptions may have delivered and trapped ice in these unlikely regions.
The study, led by Saira Hamid and her colleagues, used advanced computer models to simulate Mars’s climate and volcanic activity billions of years ago. Their results suggest that explosive eruptions between 4.1 and 3 billion years ago could have played a key role in transporting water and forming buried ice layers near the equator.
On early Mars, massive volcanoes frequently erupted with incredible force, releasing large amounts of gas and water vapor into the thin atmosphere. According to the team’s model, this vapor could have quickly frozen in the planet’s cold air, falling back to the surface as snow or ice. During a single three-day eruption, as much as five meters (around 16 feet) of ice could have accumulated in some areas.
Over time, these ice layers may have become buried under dust and volcanic debris, protecting them from evaporation and the harsh Martian environment. This means that some of this ancient ice could still be hidden beneath the surface today, waiting to be discovered by future missions.
The study also suggests that volcanic eruptions may have released large amounts of sulfuric acid into the atmosphere. This could have caused dramatic cooling, plunging Mars into a “global winter.” Such cold periods would have allowed ice to persist and build up over long stretches of time, even far from the poles.
If these models are correct, they could explain the elevated hydrogen levels that orbiters and landers have detected in Mars’s equatorial regions.
This discovery has big implications for the future of Martian exploration. Subsurface ice near the equator would be far easier for astronauts to reach than polar ice, providing a valuable source of water for drinking, fuel production, and life support.
Ultimately, this research reveals that Mars’s fiery volcanic past may have helped create—and preserve—the very ice that could support human life on the planet in the future. Hidden beneath its dusty red surface, the legacy of those ancient eruptions may still be shaping the story of Mars today.
https://knowridge.com/2025/10/volcanoes-may-have-hidden-ancient-ice-beneath-marss-equator/
