Grey Hill Zircon – A Natural High 176Yb/177Hf Zircon Reference Material for LA‐MC‐ICP‐MS Hf Isotope Measurement

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Titel: Grey Hill Zircon – A Natural High 176Yb/177Hf Zircon Reference Material for LA‐MC‐ICP‐MS Hf Isotope Measurement
Autoren: Piero A.B. de Sampaio, Hugo K.H. Olierook, Denis Fougerouse, Bradley J. McDonald, Ninna K. Jensen, James N. Connelly, William D.A. Rickard, David W. Saxey, Noreen J. Evans, Martin Bizzarro, Nicholas J. Gardiner, Joshua M. Garber, Luc S. Doucet, Zheng‐Xiang Li
Weitere Verfasser: University of St Andrews.Centre for Clean Energy Research, University of St Andrews.Centre for Energy Ethics, University of St Andrews.School of Earth & Environmental Sciences
Quelle: Geostandards and Geoanalytical Research.
Verlagsinformationen: Wiley, 2025.
Publikationsjahr: 2025
Schlagwörter: Zircon, Isobaric interference, Geochemistry and Petrology, Hf isotopes, LA-MC-ICP-MS, Geology, DAS, Reference material
Beschreibung: Accurate measurements of Hf isotope ratios in zircon rely on adequate correction for isobaric interferences, which increase in complexity as the ratio of heavy rare earth elements (HREE) to Hf increases. Currently, synthetic high‐HREE zircons are commonly used to bracket the highest naturally occurring HREE/Hf zircon grains during laser ablation‐based measurement but these are in limited supply. We present results for Grey Hill zircon, a new high 176Yb/177Hf zircon with a weighted mean age of 482.97 ± 0.17 Ma (2s). We show that Hf is homogeneously distributed at the microscale in Grey Hill zircon, whereas Yb is heterogeneously distributed in oscillatory‐ and sector‐zones following observed cathodoluminescence patterns. Atom probe tomography measurements show that Hf and Yb are homogeneously distributed at the nanoscale. Chemical abrasion solution multi‐collector inductively coupled plasma‐mass spectrometry (CA‐S‐MC‐ICP‐MS) yielded a mean 176Hf/177Hf of 0.282854 ± 0.000023 (2s, n = 15), with a correlation to 176Lu/177Hf that corresponds to radiogenic ingrowth since ca. 483 Ma. If analyses are back‐calculated to the crystallisation age, the CA‐S‐MC‐ICP‐MS data yield a 176Hf/177Hf(t) of 0.282805 ± 0.000010 (2s), which we recommend be used as the reference ratio for Grey Hill zircon. Non‐abraded, in situ LA‐MC‐ICP‐MS analyses yielded results consistent with the CA‐S‐MC‐ICP‐MS mean. Importantly, LA‐MC‐ICP‐MS analyses do not show any correlation with HREE, and there is no apparent difference in measured 176Hf/177Hf between pristine and altered domains. The grains have 176Yb/177Hf (0.094–0.48) and 176Lu/177Hf (0.0028–0.014) ratios that are much higher than all commonly used natural reference materials. Thus, Grey Hill zircon is a useful natural reference material for LA‐MC‐ICP‐MS Hf isotope measurement to guarantee accurate isobaric interference correction across the full spectrum of naturally occurring zircon grains. Grey Hill zircon concentrates can be requested from the authors.
Publikationsart: Article
Dateibeschreibung: application/pdf
Sprache: English
ISSN: 1751-908X
1639-4488
DOI: 10.1111/ggr.70016
Zugangs-URL: https://hdl.handle.net/10023/32957
Rights: CC BY
Dokumentencode: edsair.doi.dedup.....3869b0682d05b51a9bec4815570a71ef
Datenbank: OpenAIRE
Beschreibung
Abstract:Accurate measurements of Hf isotope ratios in zircon rely on adequate correction for isobaric interferences, which increase in complexity as the ratio of heavy rare earth elements (HREE) to Hf increases. Currently, synthetic high‐HREE zircons are commonly used to bracket the highest naturally occurring HREE/Hf zircon grains during laser ablation‐based measurement but these are in limited supply. We present results for Grey Hill zircon, a new high 176Yb/177Hf zircon with a weighted mean age of 482.97 ± 0.17 Ma (2s). We show that Hf is homogeneously distributed at the microscale in Grey Hill zircon, whereas Yb is heterogeneously distributed in oscillatory‐ and sector‐zones following observed cathodoluminescence patterns. Atom probe tomography measurements show that Hf and Yb are homogeneously distributed at the nanoscale. Chemical abrasion solution multi‐collector inductively coupled plasma‐mass spectrometry (CA‐S‐MC‐ICP‐MS) yielded a mean 176Hf/177Hf of 0.282854 ± 0.000023 (2s, n = 15), with a correlation to 176Lu/177Hf that corresponds to radiogenic ingrowth since ca. 483 Ma. If analyses are back‐calculated to the crystallisation age, the CA‐S‐MC‐ICP‐MS data yield a 176Hf/177Hf(t) of 0.282805 ± 0.000010 (2s), which we recommend be used as the reference ratio for Grey Hill zircon. Non‐abraded, in situ LA‐MC‐ICP‐MS analyses yielded results consistent with the CA‐S‐MC‐ICP‐MS mean. Importantly, LA‐MC‐ICP‐MS analyses do not show any correlation with HREE, and there is no apparent difference in measured 176Hf/177Hf between pristine and altered domains. The grains have 176Yb/177Hf (0.094–0.48) and 176Lu/177Hf (0.0028–0.014) ratios that are much higher than all commonly used natural reference materials. Thus, Grey Hill zircon is a useful natural reference material for LA‐MC‐ICP‐MS Hf isotope measurement to guarantee accurate isobaric interference correction across the full spectrum of naturally occurring zircon grains. Grey Hill zircon concentrates can be requested from the authors.
ISSN:1751908X
16394488
DOI:10.1111/ggr.70016