Novel Methods for Concomitant Determination of the Stable Zr Isotope Composition, Lu-Hf Isotope Systematics and U-Pb Age of Individual Zircons

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The stable Zr isotope ratios in zircon yield a novel geochemical tracer that, together with the Lu-Hf and U-Pb radiogenic isotope systems, allows for a better understanding of the magmatic evolution of silicate melts. We present a solution-based procedure for coupled stable Zr, Lu-Hf and U-Pb isotope ratio determinations for individual zircons using a 91Zr-96Zr tracer purified from Hf and a late-spiking protocol for Zr. This method yields high-precision Zr and Hf isotope results while maintaining low blank levels for U-Pb isotope and Lu/Hf ratio determinations. With a two-fold improvement on the precision relative to previous solution-based work, we report δ94ZrIPGP-Zr values (deviation of the 94Zr/90Zr ratio in the sample relative to the IPGP-Zr reference material) and associated intermediate precisions (2s) for the zircon reference materials 91500, Mud Tank, Plešovice and Penglai of -0.041 ± 0.015‰, 0.018 ± 0.013‰, 0.089 ± 0.020‰ and -0.117 ± 0.021‰, respectively. Furthermore, this method yields un-biased δ94ZrIPGP-Zr and 176Hf/177Hf results for 25-ng Zr and 0.56-ng Hf aliquots of the Mud Tank zircon with intermediate precisions (2s) of 0.027‰ and 1.7 ε (parts per ten thousand), respectively. Thus, the presented method is applicable for the analysis of extremely small and rare zircon grains.

OriginalsprogEngelsk
TidsskriftGeostandards and Geoanalytical Research
Vol/bind48
Udgave nummer1
Sider (fra-til)5-28
Antal sider24
ISSN1639-4488
DOI
StatusUdgivet - 2024

Bibliografisk note

Funding Information:
We thank Prof. Frédéric Moynier for providing the Zr‐Zr tracer and IPGP‐Zr standard, and Prof. Martin Whitehouse and Prof. Xian‐Hua Li for providing the piece of Mud Tank zircon and the Penglai zircon megacrysts, respectively, that were used in this study. Financial support for this project was provided by grants from the Carlsberg Foundation (CF18_1105) and the European Research Council (ERC Advanced Grant Agreement 833275 — DEEPTIME) to M.B. There are no conflicts to declare. Scientific editing by Thomas C. Meisel. 91 96

Publisher Copyright:
© 2023 The Authors. Geostandards and Geoanalytical Research published by John Wiley & Sons Ltd on behalf of International Association of Geoanalysts.

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