Freeze‐Thaw Cycling Accelerated Olivine Weathering and Water Sequestration on Icy Mars

Abstract Geological evidence and paleoclimate models suggest that freeze‐thaw (FT) cycling has played a pivotal role in shaping the Martian surface composition throughout geological time. Here we show the experimental investigation of the sulfuric acid weathering of olivine under simulated FT conditions (193–293 K). Our results reveal that FT cycling enhances both mechanical and chemical weathering processes, with the lifetime of olivine decreasing 23 times compared to those under continuous freezing conditions. Cryogenic weathering promotes olivine hydroxylation and generates secondary phases (e.g., hydrated sulfates and amorphous silica) that collectively retain substantial water in the solid phase. Quantitative comparisons show these cryogenic weathering products retain approximately sevenfold higher water content per unit ion release compared to equivalent materials formed at ambient temperatures. These findings highlight FT cycling as an efficient geological mechanism for simultaneous mineral alteration and water sequestration, advancing mechanistic understanding of Martian hydrological evolution and habitability potential.