Short lifespans of serpentinization in the rocky core of Enceladus: Implications for hydrogen production

The discovery of a liquid ocean on Saturn's small moon Enceladus and evidence modern hydrothermal activity provide an unexpected new environment in which to expand the search for life. However, as with age moons themselves, any therein remains area debate. Based physical chemical observations from Cassini mission we can apply known mineral dissolution rates, estimated water-rock ratios Enceladus' density, variable water flow rates within rocky core constrain durations active serpentinization. On this basis developed 1-D reactive transport model compare effect initial olivine percentage, grain size, temperature, rate timespans primary alteration size density Enceladus'. In most cases, precipitation hydrous secondary minerals results water-limited regime. An front that propagates direction then controls overall alteration. Of parameters explored, high percentages slow fluid were strongest predictors long serpentinization times, while temperature had smaller effect. annual global H2 production all cases (> 1 × 1012 mol yr?1) is several orders magnitude greater than minimum release calculated observed plume (1 109 yr?1), suggesting ongoing processes are likely nearing completion. longest timescales indicate potential up ~75 Myr, consistent weathering terrestrial peridotite massifs. If produced sourced alteration, these suggest may have only very recently – even recent past 100 Myr.