論文

査読有り
2016年1月

八ヶ岳火山の最新軽石噴火によるYt-Pm4テフラの放射性炭素年代

火山
  • 大石 雅之

60
4
開始ページ
477
終了ページ
481
記述言語
日本語
掲載種別
研究論文(学術雑誌)
DOI
10.18940/kazan.60.4_477
出版者・発行元
日本火山学会

The Yatsugatake volcano located on the volcanic front in central Japan, has been active since the Middle Pleistocene, with many N-S trending eruptive centers. Little work has been previously performed on the age determination for the Late Pleistocene and/or Holocene age. Therefore, it is necessary to reconstruct the activity during that time duration. In this paper, I report a new AMS dating result of the Yt-Pm4 tephra, which is the youngest pumice fall from the Yatsugatake volcano. The pumice fall is actually from the Yokodake, one of the volcano located on the northernmost part of Yatsugatake. A ^<14>C age of 30667±130 yr BP (32951-32333 cal BP: 2σ) was obtained from the charred wood collected at the uppermost part of the silty soil which is covered directly by the Yt-Pm4 tephra, suggesting that the eruption of the Yt-Pm4 tephra occurred at ca. 32 cal ka BP. The Yokodake consists of nine lava flows (Y_1 to Y_9, from oldest to newest). The stratigraphic position of Yt-Pm4 tephra is between Y_5 and Y_6. In addition, Okuno and Kobayashi (2010) estimated the eruptive age of Y_9 lava flow to be 2.35-2.15 cal ka BP. This means that the younger four lava flows (Y_6-Y_9) erupted in 29.85-29.65 ky. The magma discharge rate at Yokodake, including the volume of Yt-Pm4 tephra, is calculated to be ca. 0.0102 km^3/ky. It is emphasized, based on the age determination, that small-scale eruptive activities have been continuous in the northern part of Yatsugatake volcano even during Late Pleistocene and Holocene.

リンク情報
DOI
https://doi.org/10.18940/kazan.60.4_477
CiNii Articles
http://ci.nii.ac.jp/naid/110010017039
CiNii Books
http://ci.nii.ac.jp/ncid/AN10512786
URL
http://id.ndl.go.jp/bib/027049962
ID情報
  • DOI : 10.18940/kazan.60.4_477
  • ISSN : 0453-4360
  • CiNii Articles ID : 110010017039
  • CiNii Books ID : AN10512786

エクスポート
BibTeX RIS