Significant Zr isotope variations in single zircon grains recording magma evolution history.

ABSTRACT: Zircons widely occur in magmatic rocks and often display internal zonation finely recording the magmatic history. Here, we presented in situ high-precision (2SD <0.15‰ for δ⁹⁴Zr) and high-spatial-resolution (20 µm) stable Zr isotope compositions of magmatic zircons in a suite of calc-alkaline plutonic rocks from the juvenile part of the Gangdese arc, southern Tibet. These zircon grains are internally zoned with Zr isotopically light cores and increasingly heavier rims. Our data suggest the preferential incorporation of lighter Zr isotopes in zircon from the melt, which would drive the residual melt to heavier values. The Rayleigh distillation model can well explain the observed internal zoning in single zircon grains, and the best-fit models gave average zircon-melt fractionatio

SUBMITTER: Guo JL 

PROVIDER: S-EPMC7474644 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature