Japan Geoscience Union Meeting 2023

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[J] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS15] Paleoclimatology and Paleoceanography

Tue. May 23, 2023 10:45 AM - 12:00 PM International Conference Room (IC) (International Conference Hall, Makuhari Messe)

convener:Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University), Hitoshi Hasegawa(Faculty of Science and Technology, Kochi University), Atsuko Yamazaki(Graduate School of Environmental Studies, Nagoya University), Takashi Obase(Atmosphere and Ocean Research Institute, The University of Tokyo), Chairperson:Hitoshi Hasegawa(Faculty of Science and Technology, Kochi University)

10:45 AM - 11:00 AM

[MIS15-06] Palaeoceanographic significance of eolian feldspar and quartz in deep-sea clay

*Yoichi Usui1, Toshitsugu Yamazaki2 (1.Kanazawa University, 2.Atmosphere and Ocean Research Institute, The University of Tokyo)

Keywords:North Pacific, mineral, Cenozoic

Atmospheric dust archives of marine sediments have been utilized to constrain past atmospheric circulations and continental climate, but no single analytical method can reconstruct dust activities uniquely. Here, we show that feldspar and quartz in deep-sea clay from the western North Pacific reveal significant temporal variations. Sediments older than ~30 Ma are characterized by the dominance of K-feldspar over plagioclase, suggesting a provenance change around that time. In contrast, the grain size of feldspar and quartz shows up-core coarsening before the change in feldspar mineralogy, supporting an intensification of atmospheric circulation around the Eocene-Oligocene transition. Our results suggest that non-clay mineralogy of deep-sea sediments can be a powerful palaeoceanographic proxy.