Zn isotopic heterogeneity in the mantle: A melting control?

- New Zn isotope data on mantle peridotite xenoliths.
- Fertile (unmelted) Earth's mantle has uniform δ66Zn = +0.30 ± 0.03‰.
- Pristine melting residues have average δ66Zn = +0.14 ± 0.03‰.
- Modeling infers that high degrees of partial melting fractionate Zn isotopes.
- Zn isotope fractionation is also controlled by the initial pressure of melting.