Timing of Shell Size Increase and Decrease of the Planktic Foraminifer Neogloboquadrina pachyderma (Sinistral) During the Pleistocene, IODP Exp. 303 Site U1304, the North Atlantic Ocean
M Yamasaki*, 1, M Matsui1, C. Shimada2, S. Chiyonobu3, T. Sato1
1 Institute of Applied Earth Sciences, Faculty of Engineering and Resource Science, Akita University, Akita 010-8502, Japan
2 Mineral Industry Museum, Akita University, Akita 010-8502, Japan
3 Institute of Geology and Paleontology, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
We made shell size measurements of the planktic foraminifer Neogloboquadrina pachyderma (sinistral) using samples from IODP Site U1304, the North Atlantic. We found that mean and maximum shell sizes began to increase around 1.1 Ma, and that several episodic changes in test size occurred during 0.6 – 0.35 Ma. Test size reached a maximum during the late Quaternary. Based on correlation with previous investigations, we have confirmed that these changes in foraminiferal shell size occurred on an inter-ocean scale
Keywords: Planktic foraminifera, Shell size, IODP, North Atlantic, Quaternary.
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* Address correspondence to this author at the Institute of Applied Earth Sciences, Faculty of Engineering and Resource Science, Akita University, Akita 010-8502, Japan; Fax: +81-18-837-0401;