Mechanism for the subglacial formation of cryogenic brines

Abstract Cryogenic brines are under-studied, despite the fact that they may contain information about past ice-sheet behavior. form through cryoconcentration of seawater, although specific setting and mechanism formation have been debated. Previous conceptual models brine require seawater isolation from ocean in a closed basin experiencing freezing. We propose instead pore spaces marine sediments subjected to repeat cycles advance retreat. During periods basal freezing, produces hypersaline which experience downward flow driven by unstable density stratification. Our advection-diffusion model porewater chemistry evolution successfully recreates two deep Antarctic cores containing cryogenic (AND-1B AND-2A), suggesting can be formed repeated waters within subglacial sediment modern ice sheets.