Global Comparison of Aqueous Geochemistry and Dissolved H 2 / CH 4 in Continental Low Temperature Serpentinization–Influenced Environments

ABSTRACT Since the 1960s, continental serpentinization‐influenced environments have served as natural laboratories for investigating low‐temperature aqueous geochemistry involving dissolved H 2 and CH 4 , with broad implications for deep Earth elemental cycles, energy resources, and astrobiology. Here, we compiled, homogenised, and analysed geochemical data (aqueous and dissolved gas) from 34 studies focused exclusively on hyperalkaline spring seepage manifestations. The resulting database includes 2309 individual measurements spanning 16 physical and chemical variables. Tropical environments exhibited higher median values in Fe, Ni, CO 3 2− , dissolved inorganic carbon, and dissolved CH 4 . Dissolved H 2 presented the highest median values in arid and cold continental settings. The arid environment also showed the highest median values in electrical conductivity (EC) and major ions (Na + , K + , Ca 2+ , Cl − ). PCA dimension 1 (49.7%) was dominated by major ions, EC, Fe, Ni, CH 4 , and H 2 , reflecting strong controls on solute and redox‐related chemistry, while Dimension 2 (8.7%) was primarily associated with water temperature. Tropical sites clustered toward Ni, Fe, oxidation–reduction potential, and Mg 2+ , reflecting oxidising conditions and elevated metal concentrations, which are potentially derived from intense rock and soil monsoonal weathering. Arid sites trend toward OH − , Cl − , Ca 2+ , Na + , EC, and H 2 , consistent with higher surface evaporative concentration and salinity in more evolved groundwater flows. Cold and temperate sites show greater variability, with hyperalkaline fluids tending toward higher pH and H 2 . Our global comparison provides a systematic synthesis and framework for identifying both common patterns and site‐specific differences in low‐temperature continental serpentinization, underscoring the potential influence of regional hydrology, particularly groundwater flow and residence times, and water availability, in regulating conditions for H 2 and CH 4 production.