[SMP32-P21] Dissolution kinetics of forsterite olivine at >200 °C: implication for the kinetics of serpentinization.
Keywords:Serpentine, Reaction rate, Olivine, Dissolution rate
In this study, the dissolution rate of natural olivine ((Mg0.91, Fe0.09)2SiO4) was measured at 200-400 °C and 50 MPa using a flow-through reactor (Suzuki et al., 2015). A 0.5 mol/kg NaCl solution was introduced at a constant rate of 2.0 mL/min during experiments. A preliminary experiment revealed that steady-state dissolution rate of olivine at 200 °C and far-from-equilibrium conditions was ca. -4.8 [mol/m2/s] in log units. The obtained dissolution rate was consistent with the extrapolated dissolution rate (log10(Rate) = ca. -4.72 [mol/m2/s]), which was extrapolated from their pH-temperature dependence at 25-150 °C (Rimstidt et al., 2012). Based on dependences of temperature, salinity, and ΔG on dissolution rate, the timescales on hydrothermal alteration of peridotite will be discussed.
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