학술논문
An inter-laboratory evaluation of OD-3 zircon for use as a secondary U-Pb dating standard.
Document Type
Article
Author
Iwano, Hideki; Orihashi, Yuji; Hirata, Takafumi; Ogasawara, Masatsugu; Danhara, Tohru; Horie, Kenji; Hasebe, Noriko; Sueoka, Shigeru; Tamura, Akihiro; Hayasaka, Yasutaka; Katsube, Aya; Ito, Hisatoshi; Tani, Kenichiro; Kimura, Jun‐Ichi; Chang, Qing; Kouchi, Yoshikazu; Haruta, Yasuhiro; Yamamoto, Koshi
Source
Subject
*ZIRCON
*LASER ablation
*RADIOACTIVE dating
*INDUCTIVELY coupled plasma mass spectrometry
*MASS spectrometry
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Language
ISSN
1038-4871
Abstract
Zircon OD-3 from the Paleogene Kawamoto Granodiorite ( Mihara body) in Japan has been identified as a potential multi-grain secondary standard for U-Pb dating. We have carried out an inter-laboratory evaluation in order to evaluate possible heterogeneity amongst the OD-3 zircon grains. U-Pb ages were obtained using two analytical techniques (a sensitive high-resolution ion microprobe and a laser ablation-inductively coupled plasma-mass spectrometry) in eight laboratories. All the 238U-206Pb ages show good agreement, with an overall weighted average 238U-206Pb age of 33.0 ± 0.1 Ma (2σ). The U-Pb age results revealed no significant variation or heterogeneity in the U-Pb ages of the OD-3 grains. Twelve fission-track ( FT) ages from three laboratories are also reported, and have a weighted average of 32.6 ± 0.6 Ma (2σ). Despite the different closure and annealing temperatures of the U-Pb and FT chronometers, respectively, the FT age is in good agreement with the U-Pb age. This suggests that the OD-3 zircon had a relatively fast cooling history and has not experienced later thermal annealing. The chronological dataset reported here clearly demonstrates that the OD-3 zircon could be a useful and reliable secondary standard for use during U-Pb dating studies of Cenozoic zircons. [ABSTRACT FROM AUTHOR]