Integrated biostratigraphic and radiometric study on the Lower Cenomanian (Cretaceous) of Hokkaido, Japan

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概要

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• New40Ar-39Ar total fusion ages have been obtained on sanidine from tuffs in the zone of Mantelliceras saxbii (equivalent to the same subzone of the European ammonite zonation) and the zone of Graysonites wooldridgei (equivalent to the European subzone of Neostlingoceras carcitanense). Ages of 98.98±0.38 Ma and 99.16±0.37 Ma, for these zones, respectively, place new constraints on the age of the AlbianlCenomanian boundary. If the base of the Cenomanian is to be defined, as currently proposed, as the FAD of the planktonic foraminifera Rotalipora globotruncanoides then the Albian/Cenomanian boundary will be at least as old as 99.2±0.4 Ma. Some 50±10m of undated sediments lie below the lowest find of R. globotruncanoides and above bono fide uppermost Albian strata.

• 日本学士院の論文

著者

• NISHIDA Tamio

  Faculty of Culture and Education, Saga University

• OBRADOVICH John

  U.S. Geological Survey, MS963, Box 25046, Federal Center

• MATSUMOTO Tatsuro

  c/o The Kyushu University Museum

関連論文

• Devonohelicoceras hidaense, a new torticonic oncocerid (Cephalopoda) from the Lower Devonian of Central Japan
• First oncocerid cephalopod from Japan
• Integrated biostratigraphic and radiometric study on the Lower Cenomanian (Cretaceous) of Hokkaido, Japan
• A study of Mrhiliceras (Cretaceous Ammonoidea) : Studies of the Cretaceous ammonites from Hokkaido and Sakhalin-XCIII
• A study of Neocardioceras (Ammonoidea) from Hokkaido : Studies of Cretaceous ammonites from Hokkaido and Sakhalin -XCII

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