Proc. IODP, 320/321, Data report: early to middle Eocene benthic foraminifers at Sites U1331 and U1333, equatorial central Pacific Ocean, Expedition 320/321

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Chapter contents Abstract Introduction Methods Results Hole U1331C Hole U1333A Hole U1333B Early and middle Eocene benthic foraminiferal assemblages Acknowledgments References Appendix Faunal reference list Figures F1. Site map for equatorial central Pacific Ocean. F2. Benthic foraminiferal occurrences. Tables T1. Benthic foraminifers, Hole U1331C. T2. Benthic foraminifers, Hole U1333A. T3. Benthic foraminifers, Hole U1333B. Plates P1. Gaudryina, Marssonella, Karreriella, Psammosiphonella, Cyclammina, Paratrochamminoides, Ammovertellina, Tritaxia, and Thalmannammina. P2. Spiroplectammina, Vulvulina, Globulina, Nodosarella, Ellipsoidella, Pleurostomella, Marginulina, Oridorsalis, Saracenaria, Pyrulinoides, Ellipsopolymorphina, and Obliquilingulina. P3. Nodosaria, Glandulonodosaria, Dentalina, Nodosarella, and Pseudonodosaria. P4. Stilostomella, Siphonodosaria, Bandyella, Orthomorphina, Strictocostella, Elliposoidella, Pleurostomella, Nodosarella, Amplectoproductina, and Ellipsoglandulina. P5. Osangularia, Abyssamina, Virgulinopsis, Coryphostoma, Bulimina, Buliminella, Quadratobuliminella, Nonion, Globocassidulina, Aragonia, and Heronallenia. P6. Anomalinoides, Pullenia, and Lenticulina. P7. Cibicidoides. P8. Nuttallides, Gyroidinoides, Alabamina, and Oridorsalis. P9. Textularia, Eouvigerina, Stilostomella, Pullenia, Bulimina, Tappanina, Valvalabamina, Paralabamina, and Clinapertina. PDF file			Previous \| Next doi:10.2204/iodp.proc.320321.212.2013 Data report: early to middle Eocene benthic foraminifers at Sites U1331 and U1333, equatorial central Pacific Ocean, Expedition 320/321¹ Ritsuo Nomura,² Hiroyuki Takata,³ and Akira Tsujimoto² Abstract Benthic foraminiferal assemblages were studied in 44 samples from lower and middle Eocene sediments in Integrated Ocean Drilling Program (IODP) Expedition 320 Holes U1331C, U1333A, and U1333B. The benthic foraminifers from Hole U1331C were sampled in lower Eocene calcareous nannofossil Zones NP12/NP13 and radiolarian Zones RP8/RP9, and thus fall within the early Eocene climatic optimum and those from Holes U1333A and U1333B fall in the upper lower Eocene and lower middle Eocene calcareous nannofossil Zones NP15–NP17 and radiolarian Zones RP13–RP16. The benthic foraminiferal assemblages from Hole U1331C are poorly preserved, so the paleoceanographic response of the benthic assemblage to warming could not be clearly observed. The diversity of benthic assemblages in the middle Eocene is positively correlated with the carbonate content of the samples. The species Globocassidulina globosa, which has been argued to be an opportunistic species, occurred in the high-carbonate intervals. Diversities decreased coeval with an increase in abundance of radiolarians, occurring between Sections 320-U1333A-16X-5 and 16X-6, at the time of deposition of the marked carbonate poor horizon in the middle Eocene. ¹ Nomura, R., Takata, H., and Tsujimoto, A., 2013. Data report: early to middle Eocene benthic foraminifers at Sites U1331 and U1333, equatorial central Pacific Ocean, Expedition 320/321. In Pälike, H., Lyle, M., Nishi, H., Raffi, I., Gamage, K., Klaus, A., and the Expedition 320/321 Scientists, Proc. IODP, 320/321: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/iodp.proc.320321.212.2013 ² Shimane University, 1060 Nishikawatsu-cho, Matsue, Shimane 690-8504, Japan. Correspondence author: nomura@edu.shimane-u.ac.jp ³ BK21 Coastal Environmental System School, Division of Earth Environmental System, Pusan National University, Busan 609-735, Korea. Initial receipt: 30 July 2012 Acceptance: 25 March 2013 Publication: 17 October 2013 MS 320321-212 Top of page \| Previous \| Next