Prediction of self-diffusion and heterodiffusion coefficients in zircon

An empirical model interconnecting point defect parameters with bulk properties of solids has been employed to calculate the self-diffusion coefficients of O and Si in zircon. Meanwhile, the model is extended to heterodiffusions for the first time in this study, which are estimated for Pb, Ti, Li, trivalent cations (REEs: Sm, Dy, Yb), and tetravalent cations (Th, U, Hf) diffusing in zircon. For most cases, our empirically estimated diffusivities under anhydrous conditions agree well with the experimental measurements over the temperature ranges investigated in the laboratory, as compared to the estimates derived from the anion porosity, although the estimated activation energies of the diffusion have a little bit large uncertainties in some cases.

► Self-diffusion of O and Si in zircon was calculated from the compensation effect. ► Heterodiffusion coefficients in zircon were calculated from a single measurement. ► Our calculated results from the cBΩ model agree well with the experimental ones. ► The cBΩ model gives a correct estimation of the activation energy for the most cases.