title: Extreme lithium isotopic fractionation in three zircon standards (Plešovice, Qinghu and Temora).
abstract: To understand the behavior of Li in zircon, we have analyzed the abundance and isotopic composition of Li in three zircon standards (Plešovice, Qinghu and Temora) widely used for microbeam analysis of U-Pb ages and O-Hf isotopes. We have mapped Li concentration ([Li]) on large grains, using a Cameca 1280HR Secondary Ion Mass Spectrometer (SIMS). All zircons have a rim 5-20 μm wide in which [Li] is 5 to 20 times higher than in the core. Up to ~20‰ isotopic fractionation is observed on a small scale in the rims of a single zircon grain. The measured δ(7)Li values range from -14.3 to 3.7‰ for Plešovice, -22.8 to 1.4‰ for Qinghu and -4.7 to 16.1‰ for Temora zircon. The [Li] and δ(7)Li are highly variable at the rims, but relatively homogenous in the cores of the grains. From zircon rim to core, [Li] decreases rapidly, while δ(7)Li increases, suggesting that the large isotopic variation of Li in zircons could be caused by diffusion. Our data demonstrate that homogeneous δ(7)Li in the cores of zircon can retain the original isotopic signatures of the magmas, while the bulk analysis of Li isotopes in mineral separates and in bulk-rock samples may produce misleading data.
authors.affiliation: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.|ARC Centre of Excellence for Core to Crust Fluid Systems and GEMOC, Department of Earth and Planetary Sciences, Macquarie University, NSW 2019, Australia.|College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yu-Ya
authors.initials: YY
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Xian-Hua
authors.initials: XH
authors.lastname: Li
authors.affiliation: ARC Centre of Excellence for Core to Crust Fluid Systems and GEMOC, Department of Earth and Planetary Sciences, Macquarie University, NSW 2019, Australia.
authors.forename: William L
authors.initials: WL
authors.lastname: Griffin
authors.affiliation: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Yan-Jie
authors.initials: YJ
authors.lastname: Tang
authors.affiliation: ARC Centre of Excellence for Core to Crust Fluid Systems and GEMOC, Department of Earth and Planetary Sciences, Macquarie University, NSW 2019, Australia.
authors.forename: Norman J
authors.initials: NJ
authors.lastname: Pearson
authors.affiliation: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.|College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: ARC Centre of Excellence for Core to Crust Fluid Systems and GEMOC, Department of Earth and Planetary Sciences, Macquarie University, NSW 2019, Australia.|Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Mei-Fei
authors.initials: MF
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Qiu-Li
authors.initials: QL
authors.lastname: Li
authors.affiliation: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Tang
authors.affiliation: ARC Centre of Excellence for Core to Crust Fluid Systems and GEMOC, Department of Earth and Planetary Sciences, Macquarie University, NSW 2019, Australia.
authors.forename: Suzanne Y
authors.initials: SY
authors.lastname: O'Reilly