A new study suggests that massive, ancient explosive volcanic eruptions on Mars may be the source of vast, buried water-ice deposits unexpectedly found near the Red Planet's equator.
This hypothesis addresses the puzzling detection of excess hydrogen—suggestive of water ice—in low-latitude regions, such as the Medusae Fossae Formation (MFF), where surface ice is not expected to survive in the current climate.
How Volcanism Could Create Equatorial Ice
Water Injection: The models suggest that explosive eruptions, which occurred on Mars between 4.1 billion and 3 billion years ago, would have violently ejected large amounts of water vapor from the planet's interior high into the atmosphere.
Ice Precipitation: In the cold, ancient Martian atmosphere, this water vapor would have quickly frozen and fallen back to the surface as ice or snow, potentially along with volcanic ash (pyroclasts).
Insulation and Preservation: Researchers estimate that a single three-day eruption could have produced an ice deposit up to 16 feet (5 meters) thick near the volcano.
Over millions of years of repeated eruptions, these ice layers could be buried and insulated by thick layers of volcanic ash or dust, preventing them from sublimating (turning directly to gas) in the equatorial heat.
This mechanism provides an explanation for how significant stores of ice could have accumulated and persisted at low latitudes, independent of orbital changes (obliquity) that are typically blamed for moving ice away from the poles.
