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タイトルヨミ
ヤマガタケン シラタカ カザン カルデラ ノ コウゾウ ト ガンセツ ナダレ タイセキブツ
日本語以外のタイトル
Structures of the Shirataka volcanic calderas and debris avalanche deposits related to the formation of the calderas,Yamagata,Japan
ファイル
言語
日本語
著者
笹谷 晋吾
横田 修一郎
内容記述(抄録等)
Structures of the Quaternary Shirataka volcanic calderas and the occurrences of debris avalanches have been studied on the basis of field mapping data,borehole core,and paleomagnetism measurements.The debris avalanche deposits distributed in and adjacent to the calderas are determined to be 50 to 60 meters in thickness,and it extensively cover rhyolitic pyroclastic flow deposits and thick andesite lava.Although the northern and eastern walls of the calderas are not recognized,borehole data indicate the existence of low calderas wall beneath the debris avalanche deposits in the eastern portion.Therefore,the calderas shape a general horseshoe structure opening to the north.
Thin paleosols layers interbedded in the debris avalanche deposits mean that several deposition events occurred.The deposition age is estimated to be from early to middle Pleistocene.Centralization of paleomagnetism direction of the deposits means that they may have been deposited under high temperature condition influenced by the volcanic activity.Consequently,even through in several episodes,occunrences of sector collapse,formations of calderas and depositions of debris avalanches may have finished at least before several ten thousands years ago.
掲載誌名
島根大学地球資源環境学研究報告
24
開始ページ
13
終了ページ
29
ISSN
13439774
発行日
2005-12-27
NCID
AA11455176
出版者
島根大学総合理工学部地球資源環境学教室
出版者別表記
Department of Geoscience, Interdisciplinary Faculty of Science and Engineering, Shimane University
資料タイプ
紀要論文
部局
(旧組織)大学院総合理工学研究科
備考
12-14,16+ / 1993+
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