このエントリーをはてなブックマークに追加
ID 47115
本文ファイル
別タイトル
Geology of Katsuyama-Osakabe Area, Okayama Prefecture, Southwest Japan: Chaotic Rock Bodies Originated by Sedimentary and Diapiric Processes
著者
平山 恭之 大学院総合科学研究科 広大研究者総覧
NDC
地球科学・地学・地質学
抄録(他言語)
On the basis of the results of field surveying and microstructural study, we describe here the occurrence of chaotic rocks formed by diapiric processes, and the structural relationships between the Ohsayama serpentinite mélange, the Permian olistostrome, and the Sangun metamorphic rocks. The Ohsayama serpentinite mélange is distributed in the Osakabe area and was defined by Tsujimori (1998) as a tectonic mélange with a serpentinite matrix. It contains blueschist-facies schists with a metamorphic age (320 Ma) older than that of the Sangun metamorphic rocks (180 Ma), and is traceable to the north of the Permian olistostrome. The Permian olistostrome is distributed in the Katsuyama area and consists of submarine sliding deposits with mudstone, sandstone, alternating beds of sandstone and mudstone, and limestone blocks. In addition to these rocks, we newly found chaotic rocks of diapiric origin. These chaotic rocks are characterized by a predominant mud matrix and non-sorted clasts with sizes ranging from 1 mm to more than 10 m. The distribution of the chaotic rock body cuts the bedding planes of the other strata at a high angle. The clasts have irregular shapes, a zigsaw-puzzle structure, and disaggregated wisps. These features indicate that the clasts were broken and driven upward by overpressured fl uids. The Sangun metamorphic rocks, which are of a high pressure type and commonly show three generations of foliation, underlie both the Ohsayama serpentinite mélange and Permian olistostrome with a fault contact and form syncline trending E-W and plunging 7°to west at the northeast part of the surveyed area.
掲載誌名
広島大学大学院総合科学研究科紀要. II, 環境科学研究
13巻
開始ページ
19
終了ページ
39
出版年月日
2018-12-31
出版者
広島大学大学院総合科学研究科
ISSN
1881-7696
NCID
言語
日本語
NII資源タイプ
紀要論文
広大資料タイプ
学内刊行物(紀要等)
DCMIタイプ
text
フォーマット
application/pdf
著者版フラグ
publisher
権利情報
掲載された論文,研究ノート,要旨などの出版権・著作権は広島大学大学院総合科学研究科に帰属する。
Copyright (c) 2018 Graduate School of Integrated Arts and Sciences, Hiroshima University, All rights reserved.
部局名
総合科学研究科
他の一覧