Serpentinization-driven redox disequilibria in the Jezero Paleolake as a potential energy source for primitive life on early Mars

We propose that fracture-localized serpentinization of the olivine-rich Seitah formation in Jezero crater on Mars could have delivered hydrogen to sustain a redox potential. Using Perseverance data, we calculate the formation could have generated 0.7–1.3 mol H₂ per kg of serpentinized rock. H₂-rich and CO₂-poor fluids introduced to Jezero’s circumneutral paleolake bottom waters would have created a redox disequilibrium with dissolved inorganic carbon (DIC). At this pH, carbonate equilibria maintain DIC predominantly as bicarbonate (HCO₃ − , 80–95% of DIC) with dissolved CO₂(aq) suppressed (5–20%). Under low-temperature paleolake conditions (0–10 °C), the reaction is kinetically inhibited, allowing H₂–CO₂ redox disequilibria to persist. We use a sensitivity-based kinetic framework to show H 2 –CO 2 disequilibria lifetimes within Jezero extend from centuries to millions of years under representative activation energy bounds. Chemoautotrophs can exploit H₂–CO₂/HCO₃ − redox gradients. We apply an energy-flux framework, calculate chemical affinities of 10–30 kJ mol − ¹ H₂, and estimate that individual serpentinization vent fields could support microbial populations of 10¹⁴–10¹⁶ cells. Our results demonstrate that the paleolake possessed the conditions necessary to produce a redox battery that could power primitive life. Similar environments on early Mars could have had the same potential.