Zircon M127 – A Homogeneous Reference Material for SIMS U–Pb Geochronology Combined with Hafnium, Oxygen and, Potentially, Lithium Isotope Analysis

Year:

2016

Type of Publication:

Article

Keywords:

zircon, reference material, SIMS, U–Pb geochronology, oxygen isotopes, hafnium isotopes, lithium isotopes, Zircon, matériau de référence, SIMS, géochronologie U-Pb, isotopes d'oxygène, isotopes du hafnium, isotopes du lithium

Authors:

Nasdala, Lutz; Corfu, Fernando; Valley, John W.; Spicuzza, Michael J.; Wu, Fu-Yuan; Li, Qiu-Li; Yang, Yue-Heng; Fisher, Chris; Münker, Carsten; Kennedy, Allen K.; Reiners, Peter W.; Kronz, Andreas; Wiedenbeck, Michael; Wirth, Richard; Chanmuang, Chutimun; Zeug, Manuela; Váczi, Tamás; Norberg, Nicholas; Häger, Tobias; Kröner, Alfred; Hofmeister, Wolfgang

Journal:

Geostandards and Geoanalytical Research

Volume:

40

Number:

4

Pages:

457-475

ISSN:

1751-908X

BibTex:

@article{GGR:GGR12123, author = "Lutz Nasdala and Fernando Corfu and John W. Valley and Michael J. Spicuzza and Fu-Yuan Wu and Qiu-Li Li and Yue-Heng Yang and Chris Fisher and Carsten M{\"u}nker and Allen K. Kennedy and Peter W. Reiners and Andreas Kronz and Michael Wiedenbeck and Richard Wirth and Chutimun Chanmuang and Manuela Zeug and Tam{\'a}s V{\'a}czi and Nicholas Norberg and Tobias H{\"a}ger and Alfred Kr{\"o}ner and Wolfgang Hofmeister", abstract = "In this article, we document a detailed analytical characterisation of zircon M127, a homogeneous 12.7 carat gemstone from Ratnapura, Sri Lanka. Zircon M127 has TIMS-determined mean U–Pb radiogenic isotopic ratios of 0.084743 ± 0.000027 for 206Pb/238U and 0.67676 ± 0.00023 for 207Pb/235U (weighted means, 2s uncertainties). Its 206Pb/238U age of 524.36 ± 0.16 Ma (95% confidence uncertainty) is concordant within the uncertainties of decay constants. The δ18O value (determined by laser fluorination) is 8.26 ± 0.06‰ VSMOW (2s), and the mean 176Hf/177Hf ratio (determined by solution ICP-MS) is 0.282396 ± 0.000004 (2s). The SIMS-determined δ7Li value is −0.6 ± 0.9‰ (2s), with a mean mass fraction of 1.0 ± 0.1 μg g−1 Li (2s). Zircon M127 contains ~ 923 μg g−1 U. The moderate degree of radiation damage corresponds well with the time-integrated self-irradiation dose of 1.82 × 1018 alpha events per gram. This observation, and the (U–Th)/He age of 426 ± 7 Ma (2s), which is typical of unheated Sri Lankan zircon, enable us to exclude any thermal treatment. Zircon M127 is proposed as a reference material for the determination of zircon U–Pb ages by means of SIMS in combination with hafnium and stable isotope (oxygen and potentially also lithium) determination.", doi = "10.1111/ggr.12123", issn = "1751-908X", journal = "Geostandards and Geoanalytical Research", keywords = "zircon, reference material, SIMS, U–Pb geochronology, oxygen isotopes, hafnium isotopes, lithium isotopes, Zircon, mat{\'e}riau de r{\'e}f{\'e}rence, SIMS, g{\'e}ochronologie U-Pb, isotopes d{\&}#039;oxyg{\`e}ne, isotopes du hafnium, isotopes du lithium", number = "4", pages = "457--475", title = "{Z}ircon {M}127 – {A} {H}omogeneous {R}eference {M}aterial for {SIMS} {U}–{P}b {G}eochronology {C}ombined with {H}afnium, {O}xygen and, {P}otentially, {L}ithium {I}sotope {A}nal", url = "http://dx.doi.org/10.1111/ggr.12123", volume = "40", year = "2016", }

Abstract:

In this article, we document a detailed analytical characterisation of zircon M127, a homogeneous 12.7 carat gemstone from Ratnapura, Sri Lanka. Zircon M127 has TIMS-determined mean U–Pb radiogenic isotopic ratios of 0.084743 ± 0.000027 for 206Pb/238U and 0.67676 ± 0.00023 for 207Pb/235U (weighted means, 2s uncertainties). Its 206Pb/238U age of 524.36 ± 0.16 Ma (95% confidence uncertainty) is concordant within the uncertainties of decay constants. The δ18O value (determined by laser fluorination) is 8.26 ± 0.06‰ VSMOW (2s), and the mean 176Hf/177Hf ratio (determined by solution ICP-MS) is 0.282396 ± 0.000004 (2s). The SIMS-determined δ7Li value is −0.6 ± 0.9‰ (2s), with a mean mass fraction of 1.0 ± 0.1 μg g−1 Li (2s). Zircon M127 contains ~ 923 μg g−1 U. The moderate degree of radiation damage corresponds well with the time-integrated self-irradiation dose of 1.82 × 1018 alpha events per gram. This observation, and the (U–Th)/He age of 426 ± 7 Ma (2s), which is typical of unheated Sri Lankan zircon, enable us to exclude any thermal treatment. Zircon M127 is proposed as a reference material for the determination of zircon U–Pb ages by means of SIMS in combination with hafnium and stable isotope (oxygen and potentially also lithium) determination.