TY - JOUR
T1 - Characteristics in trace elements compositions of tephras (B-Tm and To-a) for identification tools
AU - Nara, Fumiko Watanabe
AU - Yokoyama, Tatsunori
AU - Yamasaki, Shin Ichi
AU - Minami, Masayo
AU - Asahara, Yoshihiro
AU - Watanabe, Takahiro
AU - Yamada, Kazuyoshi
AU - Tsuchiya, Noriyoshi
AU - Yasuda, Yoshinori
N1 - Funding Information:
Acknowledgments—We are grateful to M. Niwa (JAEA) and T. Kato (Nagoya University) for their important comments to improve this manuscript, and to S. Maruyama (KYOTO FISSION-TRACK Co. Ltd) for his comments and suggestions on the LA-ICP-MS analysis. We also acknowledge M. Shimizu, A. Sano and T. Mitsuguchi (JAEA) for their help with EPMA and LA-ICP-MS measurements at Tono Geoscience Center. We are also grateful to K. Seto (Shimane University), M. Saito-Kato (National Museum of Nature and Science) and K. Gotanda (Chiba University of Commers) for their kind support in collecting the lake sediment sample, and Dr. I. K. Abdulzahra for his kind to ensure our S-ICP results. This work is supported by the 2012 Joint Research Program (No. A-1, 2012) of International Research Institute of Disaster Science (IRIDeS), Tohoku University, Japan. We are grateful to Dr. M. Yoshikawa and anonymous reviewer for their comments to improve our paper.
Funding Information:
We are grateful to M. Niwa (JAEA) and T. Kato (Nagoya University) for their important comments to improve this manuscript, and to S. Maruyama (KYOTO FISSION-TRACK Co. Ltd) for his comments and suggestions on the LA-ICP-MS analysis. We also acknowledge M. Shimizu, A. Sano and T. Mitsuguchi (JAEA) for their help with EPMA and LA-ICP-MS measurements at Tono Geoscience Center. We are also grateful to K. Seto (Shimane University), M. Saito-Kato (National Museum of Nature and Science) and K. Gotanda (Chiba University of Commers) for their kind support in collecting the lake sediment sample, and Dr. I. K. Abdulzahra for his kind to ensure our S-ICP results. This work is supported by the 2012 Joint Research Program (No. A-1, 2012) of International Research Institute of Disaster Science (IRIDeS), Tohoku University, Japan. We are grateful to Dr. M. Yoshikawa and anonymous reviewer for their comments to improve our paper.
Publisher Copyright:
Copyright © 2021 by The Geochemical Society of Japan.
PY - 2021
Y1 - 2021
N2 - The absolute date of the Millennium Eruption (ME) of Changbaishan Volcano is widely recognized as AD 946. The Baegdusan-Tomakomai (B-Tm) tephra dispersed during the ME is a robust-age key bed. In order to identify the tephra, refractive index and major-element compositions of volcanic glass shards are conventionally used. Meanwhile, trace-element analysis using the inductively coupled plasma mass spectrometry (ICP-MS) technique for the volcanic glass shards and bulk samples of the B-Tm tephra is still limited. Here we give a detailed description of major- and trace-element compositions for the glass shards and bulk sediments of the B-Tm and Towada caldera eruptions (To-a) tephra deposits from the Lake Ogawara sediment core, Tohoku region, northern Japan to identify the tephras. The depth profiles of the major and trace elements show the significant peaks for the K2O and some trace elements (Zn, Rb, Zr, Nb, Sn, Y, La, Ce, Nd, Th, and U) at the B-Tm tephra layer in the Lake Ogawara sediment core, but no peaks of these elements at the To-a tephra layer. High concentrations of the trace elements in the B-Tm tephra layer were observed in individual glass shards as well as in the bulk sediment. These concentrations are highlighted by the elemental abundance pattern normalized by the crustal abundance. The elemental pattern in individual glass shards from other Japanese tephras showed significant differences from those of the B-Tm tephra, especially in REE compositions. The trace-element compositions of the glass shards and bulk sediments show a strong tool for distinguishing the B-Tm tephra from other Japanese tephras.
AB - The absolute date of the Millennium Eruption (ME) of Changbaishan Volcano is widely recognized as AD 946. The Baegdusan-Tomakomai (B-Tm) tephra dispersed during the ME is a robust-age key bed. In order to identify the tephra, refractive index and major-element compositions of volcanic glass shards are conventionally used. Meanwhile, trace-element analysis using the inductively coupled plasma mass spectrometry (ICP-MS) technique for the volcanic glass shards and bulk samples of the B-Tm tephra is still limited. Here we give a detailed description of major- and trace-element compositions for the glass shards and bulk sediments of the B-Tm and Towada caldera eruptions (To-a) tephra deposits from the Lake Ogawara sediment core, Tohoku region, northern Japan to identify the tephras. The depth profiles of the major and trace elements show the significant peaks for the K2O and some trace elements (Zn, Rb, Zr, Nb, Sn, Y, La, Ce, Nd, Th, and U) at the B-Tm tephra layer in the Lake Ogawara sediment core, but no peaks of these elements at the To-a tephra layer. High concentrations of the trace elements in the B-Tm tephra layer were observed in individual glass shards as well as in the bulk sediment. These concentrations are highlighted by the elemental abundance pattern normalized by the crustal abundance. The elemental pattern in individual glass shards from other Japanese tephras showed significant differences from those of the B-Tm tephra, especially in REE compositions. The trace-element compositions of the glass shards and bulk sediments show a strong tool for distinguishing the B-Tm tephra from other Japanese tephras.
KW - B-Tm tephra
KW - Changbaishan Volcano
KW - Lake Ogawara
KW - The Millennium Eruption
KW - Trace element compositions
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U2 - 10.2343/geochemj.2.0619
DO - 10.2343/geochemj.2.0619
M3 - Article
AN - SCOPUS:85120784917
SN - 0016-7002
VL - 5
SP - 117
EP - 133
JO - Geochemical Journal
JF - Geochemical Journal
IS - 3
ER -