日本海拡大変動と大陸リソスフェアの流動(<特集>ユーラシア東縁における白亜紀-中新世テクトニクス-リフティングはいかに準備されたか-)

• 竹下 徹

  愛媛大学理学部地球科学教室

書誌事項

タイトル別名

• Diastrophism and ductile flow in continental lithosphere associated with the Japan Sea opening
• 日本海拡大変動と大陸リソスフェアの流動
• ニホンカイ カク ダイ ヘンドウ ト タイリク リソスフェア ノ リュウドウ

抄録

In this paper, the Japan Sea opening and accompanied large scale ductile flow in continental lithosphere, a big diastrophism which occured in Miocene, in proto-Japan arc are investigated. The essence of continental rifting is the thinning of continental lithosphere by ductile flow in rocks. Therefore, rigid-plate tectonics which has been believed so far is no longer justified in the case of continental extension. Instead, we should take into account realistic flow laws for contstituent rocks of continental lithosphere to analyze continental deformation. In areas of high geothermal gradients such as continental arc, it is shown by computer simulation that ductile stretching in the S lithosphere responsible for continental extension occurs quite easily under reasonable intraplate stresses less than 200 bars. Such a continental extension is accelerated and completed (continental breakup) only within a few Ma, which is in good agreement with observed duration of back-arc rifting such as that in Japan and Italy (opening of the Tyrrhenian Sea). A preliminary investigation of crustal deformation in the forearc region of southwestern Japan is described. At the time of the Japan Sea opening, continental extension occurred and small scale rifted basins formed along the MTL and in the forearc region in southwestern Japan. However, at the culmination of the Japan Sea opening contemporaneous with the clockwise rotation of southwestern Japan (15 Ma, Otofuji and Matsuda, 1984), the forearc region was under a strong N-NNE tending compressional stress field, and was consequently shortened. Possibe causes for such forearc shortening associated with back-arc extension are (1) friction between subducting plate and overlying (arc) plate, and (2) the effect that overlying plate is draged toward trench by the secondary flow caused by plate subduction.

収録刊行物

• 地球科学

  地球科学 45 (5), 319-332, 1991

  地学団体研究会

詳細情報

• CRID: 1390282679210292864
• NII論文ID: 110007092667
• NII論文ID: 10003416460
• NII書誌ID: AN00141269
• DOI: 10.15080/agcjchikyukagaku.45.5_319
• ISSN: 21897212
• ISSN: 03666611
• NDL書誌ID: 3740524
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I3740524
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可