Upper Triassic siliceous micrite in the Mt. Funabuseyama area of the western part of the Mino terrane, central Japan

• Sano Hiroyoshi

  Department of Earth and Planetary Sciences, Kyushu University

• Kuwahara Kiyoko

  Faculty of Clinical Education, Ashiya University

• Yao Akira

  Department of Geosciences, Graduate School of Science, Osaka City University

• Onoue Tetsuji

  Department of Earth and Environmental Sciences, Kagoshima University

Bibliographic Information

Other Title

• 美濃帯西部，舟伏山地域の上部三畳系珪質ミクライト
• ミノタイ セイブ フナブセヤマチイキ ノ ジョウブ サンジョウケイケイシツ ミクライト

Abstract

Siliceous micrite crops out in close association with bedded chert and nodular chert in the Middle Jurassic melange of the Mino terrane in the Mt. Funabuseyama area, central Japan. The siliceous micrite and chert form a characteristic lithologic association of a siliceous micrite-chert facies (ca. 60 m thick) in a bedded chert succession. The siliceous micrite is light gray and occurs as thin, lenticular beds in thin-bedded chert and as irregular-shaped blocks in thick-bedded to massive chert. The siliceous micrite is described as radiolarian lime-mudstone that includes subordinate thin-shelled bivalves within a lime-mud matrix. Conodont and radiolarian fossils indicate a Carnian to lower Norian age for the siliceous micrite and associated bedded chert.<br>We interpret the Upper Triassic siliceous micrite as deep-water sediment deposited in a pelagic setting within a mid-oceanic realm. This interpretation implies that short-lived fluctuations of the carbonate compensation depth occurred in Carnian to early Norian time, probably due to the intermittent accumulation of lime mud derived from calcareous nannoplankton.<br>The Upper Triassic siliceous micrite-chert facies differs in containing siliceous micrite from the coeval bedded chert of the oceanic plate stratigraphy of the Mino terrane. We postulate that compared with the Upper Triassic chert, the siliceous micrite-chert facies accumulated on a topographic high at relatively shallow water-depths, probably near the carbonate compensation depth. The Upper Triassic siliceous micrite-chert facies is inferred to have accumulated on the lower slope of a mid-oceanic seamount. We suggest an alternative age of Early Permian or Middle-Late Triassic for the formation of the mid-oceanic seamount.

Journal

• The Journal of the Geological Society of Japan

  The Journal of the Geological Society of Japan 116 (6), 321-340, 2010

  The Geological Society of Japan

Keywords

• Mino Terrane
• Mt. Funabuseyama area
• Upper Triassic
• siliceous micrite
• chert

Details

• CRID: 1390001206237585024
• NII Article ID: 130000413445
• NII Book ID: AN00141768
• DOI: 10.5575/geosoc.116.321
• ISSN: 13499963
• ISSN: 00167630
• NDL BIB ID: 10757426
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I10757426
• Web Site: https://www.jstage.jst.go.jp/article/geosoc/116/6/116_6_321/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed