Fig. 3: Plots showing Zn isotopic variation (Δ66Zn = δ66Znsample – δ66Zninitial) versus the fraction of retained Zn (fZn) related to the Zn evaporative loss.
From: Impact-induced sublimation drives volatile depletion in carbonaceous meteorites
Dashed lines represent the Zn isotopic fractionation factors. In (A), the α values range from 0.9999 to 0.9990, indicating the limited Zn isotopic fractionation expected under high-P conditions associated with impact events. The data sources of reported materials are summarized in reference34. In (B), theoretical fractionation factors for evaporation into a high vacuum are displayed (0.9753 for elemental Zn, 0.9897 for ZnS, and 0.9927 for ZnCl2). The CI chondrites ([Zn] = 309 µg/g; δ66Zn = 0.46‰)12,14,49 are used to represent the starting material for CY chondrites. The initial material for CM chondrites is based on the water- and volatile-rich CM sample Lonewolf Nunataks 94101 (LON 94101; [Zn] = 144 µg/g; δ66Zn = 0.32‰)19. Small colored dots in the background represent results from a Monte Carlo simulation. The simulation follows the Rayleigh distillation model: δ66Zn = (1000 + δ66Zn0) × f α−1 – 1000, where δ66Zn0 is the initial Zn isotopic composition, α is the fractionation factor, and f is the evaporative loss ratio of Zn. The δ66Zn0 is assigned randomly following a normal distribution (mean ± σSD). The simulation incorporates isotopic fractionation under different scenarios characterized by α values of 0.9847 (±0.00005), 0.9897 (±0.00005), 0.9927 (±0.00005), and 0.9990 (±0.00005). Each scenario is simulated over 10,000 trials to ensure robust statistical outcomes. The f is randomly selected between 0 and 1 in each trial.
