Sealevel history recorded in the Pleistocene carbonate sequence in IODP Hole 310‐M0005D,off Tahiti |
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| Authors: | Yasufumi Iryu Yasunari Takahashi Kazuhiko Fujita Gilbert Camoin Guy Cabioch Hiroki Matsuda Tokiyuki Sato Kaoru Sugihara Jody M. Webster Hildegard Westphal |
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| Affiliation: | 1. Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya 464‐8601, Japan (email: iryu.yasufumi@a.mbox.nagoya‐u.ac.jp);2. Institute of Geology and Paleontology, Graduate School of Science, Tohoku University, Aobayama, Sendai 980‐8578, Japan;3. Department of Physics and Earth Sciences, University of the Ryukyus, Okinawa 903‐0213, Japan;4. Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, (CEREGE), UMR 6635 CNRS, Europ?le Méditerranéen de l'Arbois, BP 80, F‐13545 Aix‐en‐Provence Cedex 4, France;5. Institut de Recherche pour le Déloppement, Bondy Cedex, France;6. Department of Earth Sciences, Graduate School of Technology and Science, Kumamoto University, Kurokami 2‐39‐1, Kumamoto 860‐8555, Japan;7. Institute of Applied Earth Sciences, Faculty of Engineering and Resource Science, Akita University, Teagata‐Gakuencho 1‐1, Akita 010‐8502 Japan;8. Center for Global Environmental Research (CGER), National Institute for Environmental Studies (NIES), 16‐2 Onogawa, Tsukuba, Ibaraki 305‐8506, Japan;9. School of Geosciences, The University of Sydney, Sydney, NSW, 2006, Australia;10. MARUM, Center for Marine Environmental Sciences, Universit?t Bremen, Leobener Stra?e, 28359 Bremen, Germany |
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| Abstract: | Material cored during the Integrated Ocean Drilling Program (IODP) Expedition 310 ‘Tahiti Sea Level’ revealed that the fossil reef systems around Tahiti are composed of two major stratigraphic sequences: (i) a last deglacial sequence; and (ii) an older Pleistocene sequence. The older Pleistocene carbonate sequence is composed of reef deposits associated with volcaniclastic sediments and was preserved in Hole 310‐M0005D drilled off Maraa. Within an approximately 70‐m‐thick older Pleistocene sequence (33.22–101.93 m below seafloor; 92.85–161.56 m below present sealevel) in this hole, 11 depositional units are defined by lithological changes, sedimentological features, and paleontological characteristics and are numbered sequentially from the top of the hole downward (Subunits P1–P11). Paleowater depths inferred from nongeniculate coralline algae, combined with those determined by using corals and larger foraminifers, suggest two major sealevel rises during the deposition of the older Pleistocene sequence. Of these, the second sealevel rise is associated with an intervening sealevel drop. It is likely that the second sealevel rise corresponds to that during Termination II (TII, the penultimate deglaciation, from Marine Isotope Stages 6 to 5e). Therefore, the intervening sealevel drop can be correlated with that known as the ‘sealevel reversal’ during TII. Because there are limited data on the Pleistocene reef systems in the tropical South Pacific Ocean, this study provides important information about Pleistocene sealevel history, the evolution of coral reef ecosystems, and the responses of coral reefs to Quaternary climate changes. |
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| Keywords: | DP Hunter Hole M0005D IODP Expedition 310 ‘ Tahiti Sea Level’ Pleistocene sealevel change Tahiti |
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