TY - JOUR
T1 - Age of Matuyama-Brunhes boundary constrained by U-Pb zircon dating of a widespread tephra
AU - Suganuma, Yusuke
AU - Okada, Makoto
AU - Horie, Kenji
AU - Kaiden, Hiroshi
AU - Takehara, Mami
AU - Senda, Ryoko
AU - Kimura, Jun Ichi
AU - Kawamura, Kenji
AU - Haneda, Yuki
AU - Kazaoka, Osamu
AU - Head, Martin J.
N1 - Publisher Copyright:
© 2015 Geological Society of America.
Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/4/24
Y1 - 2015/4/24
N2 - 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.
AB - 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.
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U2 - 10.1130/G36625.1
DO - 10.1130/G36625.1
M3 - Article
AN - SCOPUS:84929616855
SN - 0091-7613
VL - 43
SP - 491
EP - 494
JO - Geology
JF - Geology
IS - 6
ER -
