Elucidating the kinetics and mechanisms of heteroepitaxial nucleation and growth at mineral-water interfaces is critical to the development of predictive geochemical models since heteroepitaxy may lead to non-equilibrium conditions that cannot be described based solely on thermodynamic equilibrium assumptions. However, our understanding of heteroepitaxial nucleation and growth in conditions relevant to natural systems is limited due to the difficulties in detecting and probing mineral coatings and the lack of theoretical support. In the present work, the formation of heteroepitaxial carbonate coatings at calcite-water interfaces was investigated by exposing calcite (104) surfaces to divalent metal cation-bearing solutions supersaturated with respect to the coating phase. Heteroepitaxial growth experiments were performed using cadmium and manganese solutions of varying concentrations to cover a range of lattice misfits and saturation indices. In situ atomic force microscopy and ex situ X-ray photoelectron spectroscopy were employed to probe the reaction kinetics and the nature of the coating phases.

Heteroepitaxial nucleation and growth of metal carbonates at the calcite-water interface

245th National Meeting (2013)

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