Isotopic communication across the water - rock interface: Preservation in solids and signatures in fluids

Water - rock interactions are characteristically associated with isotopic fractionation between phases, yet their remains significant uncertainty in the degree to which these isotope ratios record the conditions of mineral formation or equilibration, and thus their fidelity as proxy records. Here, we present a novel generic modeling framework allowing sub-grid scale tracking of the isotopic signatures recorded in newly formed minerals over the timescale of precipitation and continued isotopic exchange between phases. We demonstrate that the surface area of the solid phase strongly influences the extent to which isotopes reflect the conditions of formation through time.