[M-IS16] Paleoclimatology and paleoceanography

[MIS16-P20] Integrated stratigraphy of the sediment core retrieved from the Manihiki Plateau in the central Pacific and the paleotemperature change for the last 800 kyr

*MISAKI URAKAMI¹, Takuya Sagawa², Yoshimi Kubota³ (1.College of Science and Engineering, Kanazawa University, 2.Institute of Science and Engineering, Kanazawa University, 3.National Museum of Nature and Science)

East-west sea surface temperature (SST) difference in the tropical Pacific like today developed after about 1.7 million years ago. Although many previous studies have investigated the evolution of the tropical Pacific SST using sediment cores in the east and west tropical Pacific, the central tropical Pacific SST is not well understood mainly due to the lack of long and continuous Pliocene/Pleistocene proxy record. The Manihiki Plateau is located at the southeastern edge of WPWP and is ideally situated to discuss the central tropical Pacific temperature changes. Here, we constructed an age model of the piston cores collected from the Manihiki Plateau (KR99-12 PC05) based on the magnetostratigraphy, the planktonic foraminiferal biostratigraphy, and the oxygen isotope stratigraphy. We obtained a total of 11 age constraints including four planktonic foraminiferal biohorizons and seven oxygen isotopic stratigraphic horizons in addition to five paleomagnetic polarity reversals reported by previous research. The results indicate that the core PC05 is continuously accumulated for the last 2.2 Ma with sedimentation rate of ~0.8 cm/kyr. We will also discuss the central Pacific SST change for the last 800 kyr reconstructed by Mg/Ca-paleothermometry of planktonic foraminifera.