Numerical Model of Diffusion-Driven Fe–Mg Isotopic Fractionation

FeMg_diffusion_modeling.py: Python script modeling isotopic fractionation in Mg–Fe interdiffusion systems. The algorithm follows Dauphas et al., (2010) and Sio et al., (2013). MELTS_results.dat: Output from MELTS simulations for the magmatic evolution of CE-5 basalts. FeMg_diffusion_modeling.py reads this data to set initial diffusion temperatures (T0) for olivine grains with different compositions in CE-5 basalts. The four columns represent temperature (T), molar fraction of forsterite in olivine (Fo), mass fraction of olivine (ol_frac, %), mass fraction of melt (melt_frac, %). CE-5 basalt clast.xlsx: Table S1. Measured isotopic data of mineral separates from a CE-5 basalt clast (#CE5C0000YJYX048). Table S2. Measured chemical data of mineral separates from the CE-5 basalt clast. Table S3. The mineral abundance in each mineral separate, which is calculated based on the chemical data and the compositions of minerals in the clast (Boschi et al., 2023). Table S4. Modeled cooling rates of three olivine samples. Different combinations of βFe and βMg are used to assess the effects of varying β values and potential anisotropy.