仙台市名取川ルートの中部中新統旗立層における浮遊性有孔虫化石群集の層位変化

概要

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We analyzed planktonic foraminiferal assemblages of the Middle Miocene Hatatate Formation distributed along the Natori-gawa River in the southwestern part of Sendai City, Northeast Honshu, Japan. The Hatatate Formation mainly consists of fine-grained sandstone with intercalating tuff beds served as key beds. According to index species, we recognized seven biohorizons. The studied sequence is correlated with planktonic foraminiferal Zones N.12 to N.14. These results are generally concordant with previous studies including diatom biostratigraphy and fission-track ages. The temporal changes of assemblages indicate a pair of cooling and warming events of surface water at the middle to upper part of the studied sequence. The cooling event corresponds to the oxygen isotope peak event Mi5.
日本古生物学会の論文
2013-09-30