Age of Matuyama-Brunhes boundary constrained by U-Pb zircon dating of a widespread tephra

Yusuke Suganuma, Makoto Okada, Kenji Horie, Hiroshi Kaiden, Mami Takehara, Ryoko Senda, Jun Ichi Kimura, Kenji Kawamura, Yuki Haneda, Osamu Kazaoka, Martin J. Head

研究成果: Contribution to journalArticle査読

54 被引用数 (Scopus)

抄録

The youngest geomagnetic polarity reversal, the Matuyama-Brunhes boundary (MBB), provides an important datum plane for sediments, ice cores, and lavas. Its frequently cited age of 780 ka is based on orbital tuning of marine sedimentary records, and is supported by 40Ar/39Ar dating of Hawaiian lavas using recent age calibrations. Challenging this age, however, are reports of younger astrochronological ages based on oxygen isotope stratigraphy of high-sedimentation-rate marine records, and cosmogenic nuclides in marine sediments and an Antarctic ice core. Here, we present a U-Pb zircon age of 772.7 ± 7.2 ka from a marinedeposited tephra just below the MBB in a forearc basin in Japan. U-Pb dating has a distinct advantage over 40Ar/39Ar dating in that it is relatively free from assumptions regarding standardization and decay constants. This U-Pb zircon age, coupled with a newly obtained oxygen isotope chronology, yields an MBB age of 770.2 ± 7.3 ka. Our MBB age is consistent with those based on the latest orbitally tuned marine sediment records and on an Antarctic ice core. We provide the first direct comparison between orbital tuning, U-Pb dating, and magnetostratigraphy for the MBB, fulfilling a key requirement in calibrating the geological time scale.

本文言語英語
ページ(範囲)491-494
ページ数4
ジャーナルGeology
43
6
DOI
出版ステータス出版済み - 4 24 2015
外部発表はい

All Science Journal Classification (ASJC) codes

  • 地質学

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