[M-IS02] Evolution and variability of the Asian Monsoon and Indo-Pacific climate during the Cenozoic Era

[MIS02-P05] Evaluation of synchrony in coiling direction change of planktonic foraminifera Pulleniatina in the central and western tropical Pacific

*佐川 拓也¹、浦上 美沙樹²、河潟 俊吾³、久保田 好美⁴ (1.金沢大学理工研究域、2.金沢大学大学院自然科学研究科、3.横浜国立大学、4.国立科学博物館)

キーワード：熱帯太平洋、海洋表面水温、浮遊性有孔虫

Coiling directions of planktonic foraminifera Pulleniatina have changed over time, and its timings are synchronized in the tropical Pacific and Indian Oceans. For this reason, the coiling direction change has been used as a tool for stratigraphic correlation since the late 1970’s. Because age estimates at that time relied on magnetic polarity boundary, the synchrony in coiling direction change has not been evaluated on the glacial-interglacial time-scale. Here, we investigated the coiling direction change of Pulleniatina in two sediment cores from the western and central tropical Pacific for the last 2.2 Myr. The cores are dated by oxygen isotope stratigraphy, allowing us to evaluate the synchrony of coiling direction change events. The pattern and timing of events in two cores are generally similar, with a few exceptions. The results of this study confirm the validity of coiling direction change as a stratigraphic correlation tool.