Overview

• Published in Science Advances, the study proposes that eruptions released reduced sulfur gases that could have trapped heat and allowed transient liquid water billions of years ago.
• The models favor H2S, S2, and possibly SF6 over SO2 as dominant volcanic outputs, indicating a chemically reduced atmosphere more capable of warming the planet.
• Curiosity’s discovery of an outcrop of elemental sulfur provides observational support for the prediction that emitted sulfur would precipitate in pure form on the surface.
• Comparisons between reduced sulfur in Martian meteorites and oxidized sulfur on the surface point to active sulfur cycling that would have shaped climate and mineralogy.
• The team plans further simulations to probe sources of early Martian water and assess whether volcanic sulfur chemistry could have sustained habitable niches.