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

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• 作者：Lutz Nasdala ; Fernando Corfu ; John W. Valley ; Michael J. Spicuzza ; Fu-Yuan Wu ; Qiu-Li Li ; Yue-Heng Yang ; Chris Fisher ; Carsten Mü ; nker ; Allen K. Kennedy ; Peter W. Reiners ; Andreas Kronz ; Michael Wiedenbeck ; Richard Wirth ; Chutimun Chanmuang ; Manuela Zeug ; Tamá ; s Vá ; czi ; Nicholas Norberg ; Tobias H&auml ; ger ; Alfred Krö ; ner and Wolfgang Hofmeister
• 刊名：Geostandards and Geoanalytical Research
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：40
• 期：4
• 页码：457-475
• 全文大小：1159K
• ISSN：1751-908X

文摘

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.