ИСТИНА

Diffusion coefficients for Fo and Ni in olivine (DFo and DNi) are available for temperatures from 750 to 1400 °C, experiments were carried out on high-Fo olivine close to Fo90, from 1 bar to 120 kbar pressure, and an oxygen fugacity between 10-10 and 10-4 Pa, see review in (Chakraborty, 2010). Chakraborty (2010) built a set of formulas that quantitatively describe the dependency of DNi and DFo on olivine composition, P-T-fO2 conditions, and crystal orientation. Dohmen et al. (2007) and Chakraborty (2010) noted DNi may be "slightly slower" or "slightly smaller" compared to DFo. At the same time, other authors found DNi might be slightly higher than DFo under some conditions (e.g. Fig. 1 from Lynn et al., 2018). Given these uncertainties, we evaluate existing information about the relative diffusivities of Fo and Ni, which is crucial for the analysis of the Fo-Ni relationships.