Early Pleistocene Ostracods from the Hamada Formation in the Shimokita Peninsula, Northeastern Japan: the Palaeobiogeographic Significance of their Occurrence for the Shallow-Water Fauna
書誌事項
- 公開日
- 2010-04
- DOI
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- 10.2517/1342-8144-14.1.001
- 公開者
- The Paleontological Society of Japan
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説明
Abstract. The early Pleistocene ostracod fauna from the Hamada Formation (ca. 1.5–1.2 Ma) was investigated in the Shimokita Peninsula, northeastern Japan. Twelve samples of this fossil fauna yielded 184 species, many of which are representative upper-shelf ostracods in the modern northeastern Japan Sea. Three biofacies were defined by Q-mode cluster analysis. The two most abundant species for each biofacies are Neonesidea sp. and Schizocythere kishinouyei in biofacies N, Buntonia hanaii and Yezocythere hayashii in biofacies B, and Laperousecythere robusta and Finmarchinella daishakaensis in biofacies L. The depositional environment of the individual biofacies can be defined as (1) upper-shelf area under open-sea influence in relatively high salinity (biofacies N), (2) inner—central-bay area, with relatively low salinity (biofacies B), and (3) bay-mouth area with intermediate salinity levels between those of (1) and (2) (biofacies L). Water depth decreased from the upper-shelf area through to the bay-mouth...
収録刊行物
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- Paleontological Research
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Paleontological Research 14 (1), 1-18, 2010-04
The Paleontological Society of Japan