10:45 〜 11:00
[MIS15-06] Palaeoceanographic significance of eolian feldspar and quartz in deep-sea clay
キーワード：北太平洋、鉱物、新生代
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.