Elemental partitioning in growing minerals: A theoretical model of non-equilibrium partitioning base

Abstract

In this talk, I will introduce the classical layer-by-layer crystal growth theory and a new theoretical model for impurity incorporation into growing minerals. The heterogeneous compositional distribution inside minerals is observed due to the surrounding chemical compositional variations during mineral growth. This is called a compositional zonal structure. However, considering the kinetics of elements at the crystal surface, the mineral composition can change in response to changes in supersaturation even if the surrounding chemical composition is unchanged. This is because the behavior at the crystal surface is different for each element. I have formulated the fraction of impurities incorporated into crystals as a function of supersaturation, taking into account the differences in surface behavior of the host elements, which mainly constitute the crystal, and other impurity elements. The new model of elemental partitioning may provide new perspectives on the causes of compositional zonal structure of minerals.