Japan Geoscience Union Meeting 2016

Presentation information


Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS17] Paleoclimatology and paleoceanography

Tue. May 24, 2016 3:30 PM - 5:00 PM A04 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Tomohisa Irino(Faculty of Environmental Earth Science, Hokkaido University), Minoru Ikehara(Center for Advanced Marine Core Research, Kochi University), Akira Oka(Atmosphere and Ocean Research Institute, The University of Tokyo), Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University), Ikuko Kitaba(Research Centre for Palaleoclimatology, Ritsumeikan University), Akihisa Kitamura(Institute of Geosciences, Faculty of Science, Shizuoka University), Masaki Sano(Research Institute for Humanity and Nature), Ryuji Tada(Department of Earth and Planetary Science, Graduate School of Science, The Univeristy of Tokyo), Takeshi Nakagawa(Ritsumeikan University), Akira Hayashida(Department of Environmental Systems Science, Doshisha University), Chair:Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University)

4:15 PM - 4:30 PM

[MIS17-34] Deep-sea Circulation Turnover Recognized in the Transition Period from the Warm Period to the Cool Period in the Cretaceous

*Shusuke Okawara1, Kunio Kaiho1, Minoru Ikehara2 (1.Graduate School of Science and Faculity of Science, Tohoku University, 2.Center for Advanced Marine Core Research, Kochi University)

Keywords:Cretaceous, Deep-sea circulation, benthic foraminifera, carbon isotope, oxygen isotope

Globally warm climates from the Albian to the Coniacian were followed by cool climates from the Campanian to the Maastrichtian. Although deep-sea circulation is related to global climate, this relationship remains unclarified in the Cretaceous. This paper reconstructed deep-sea circulation during the middle to late Cretaceous using carbon and oxygen isotopes from benthic foraminiferal tests at 1,000-2,000 m paleowater depth in the Pacific, Indian, North Atlantic, South Atlantic, and Southern Oceans. The carbon isotope data showed that the water masses in the Pacific and Indian Oceans were newer than those in the North Atlantic during the early Cenomanian and Coniacian, but the reverse occured during the OAE 2, the mid-Campanian, and the Maastrichtian. Deep-sea temperature determinations based on the oxygen isotope data showed that the reverse of the global deep-sea circulation characterized the transition from the warm to the cool period. Based on the current understanding of the relationship between deep-sea circulation and temperature during the Paleocene-Eocene Thermal Maximum, the sources of the warm-water circulation culminated at the OAE 2 wheras the cool-water circulation derived from the middle-low latitudes and high latitudes.