Effect of F-B-H2O on Zr diffusion in granitic melts: Implications for Zr mineralization and zircon growth

These data are supplementary data for the manuscript entitled "Effect of F-B-H2O on Zr diffusion in granitic melts: Implications for Zr mineralization and zircon growth". As a critical strategic metal, zirconium (Zr) is commonly associated with granitic rocks enriched in H2O, F and B. However, the individual and joint influence of these volatiles on Zr diffusion remains largely unclear. In this study, we conducted zircon dissolution experiments using a piston cylinder apparatus at 0.5 GPa and 1200–1400°C to determine Zr diffusivity in granitic melts with varying volatile concentrations as well as melt compositions. Our results showed that Zr diffusivity in hydrous peralkaline melts is ~4 times higher than those in hydrous metaluminous and peraluminous melts. In peralkaline melts with individual volatile present, Zr diffusivity increased with addition of F and H2O, whereas displayed a non-monotonic trend with increasing B2O3 concentration. In systems where multiple volatiles (F, B and H2O) coexist, the enhancement of Zr diffusivity was significantly weaker than the direct superposition of their individual effects. The effect of individual volatile is related to their distinct dissolution mechanisms, and the joint effect of multiple volatiles may be attributed to their mutually dependent speciation.