Preliminary report on Pliocene radiolarians from the Nobori Formation, Tonohama Group, Shikoku, Southwest Japan

• Main Authors: SUGIYAMA, Kazuhiro, 3250, NOBUHARA, Takami, 3251, INOUE, Keisuke, 3252
• Language: English
• Published: Dept. of Earth and Planetary Sciences, Nagoya University 1992
• Subjects: Planktonic foraminifera
• Online Access: http://hdl.handle.net/2237/2811

1992-12 99 taxa of radiolarians were discriminated from the type section of the Nobori Formation, Tonohama Group, Shikoku, Southwest Japan. The preliminary investigation has revealed that the type locality of the formation, also that of planktonic foraminifera Globorotalia tosaensis whose first appearance defines the base of the zone N21,is correlative with both the Sphaeropyle langii zone (mid latitude) and the Spongaster pentas zone (low-latitude) and that the age is middle to late Pliocene. The Nobori radiolarian fauna is considered to be a transitional type from typical low- to mid-latitude fauna, and is characterized by the predominant occurrence of pyloniaceans, on the other hand, the nassellarians are relatively rich in Cycladophora pliocenica representing one of cold water species. Pseudodictyophimus hexaptesimus, Bathropyramis (?) pyrgina, Eucyrtidium lene are newly described. departmental bulletin paper