The zirconium stable isotope compositions of 22 geological reference materials, 4 zircons and 3 standard solutions

Shengyu Tian (1) , Edward C. Inglis (1) , John B. Creech (2) , Wen Zhang (3) , Zaicong Wang (3) , Zhaochu Hu (3) , Yongsheng Liu (3) , Frédéric Moynier (1)

1 IPGP (UMR_7154) - Institut de Physique du Globe de Paris
2 Macquarie University
3 CUG - China University of Geosciences [Wuhan]

We report stable Zr isotope compositions of four common natural zircon grains: Penglai, 91500, GJ-1 and Mud Tank, and 22 whole rock reference materials which include fifteen magmatic rocks, one metamorphic rock, six sediments or sedimentary rocks. In addition, the isotopic calibration of the three Zr standard solutions used in different publications (IPGP-Zr, SRM3169, NIST) has been determined. The data are reported as δ94/90ZrIPGP-Zr, the permille deviation of the 94Zr/90Zr ratio relative to the IPGP-Zr standard solution. The isotopic offsets among the three Zr standard solutions are small (less than 0.033 ± 0.033‰). The isotopic composition of the zircons agrees well with previous in-situ measurements, validating the in-situ measurements. On the other hand, all the samples analyzed in this study show a large range of Zr isotope compositions of 0.602‰. This confirms the fairly large natural Zr isotopic variations. The general variation of δ94/90ZrIPGP-Zr with magmatic evolution of the various igneous samples is in agreement with previous studies, with the most magmatically evolved samples being the isotopically heavier. The two magmatic zircons are isotopically lighter compared to the magmatic rocks, which is in agreement with the enrichment of heavy isotope in the evolved samples. This is ultimately controlled by the crystallization of isotopically light zircons.

Domaines: Planète et Univers [physics]

Shengyu Tian, Edward C. Inglis, John B. Creech, Wen Zhang, Zaicong Wang, et al.. The zirconium stable isotope compositions of 22 geological reference materials, 4 zircons and 3 standard solutions. Chemical Geology, 2020, 555, pp.119791. ⟨10.1016/j.chemgeo.2020.119791⟩. ⟨insu-02943024⟩