[M-IS12] 古気候・古海洋変動

[MIS12-17] Unraveling the Mystery of Marine Isotope Stage 11c Interglacial: Insights from Speleothem Records and North Atlantic Paleoclimate Data

*Hsun-Ming Hu¹、Gianluca Marino、Carlos Pérez-Mejías、Christoph Spötl、Yusuke Yokoyama、Jimin Yu、Eelco Rohling、Akihiro Kano、Patrick Ludwig、Joaquim G. Pinto、Chuan-Chou Shen (1.National Taiwan University)

キーワード：Marine Isotope Stage 11, Speleothem, Termination V

The Marine Isotope Stage (MIS) 11c interglacial and its preceding glacial termination present a fascinating puzzle of an exceptionally strong climate response to relatively weak insolation forcing. The lack of precise radiometric age control has hindered a detailed understanding of the insolation-climate relationship during this intriguing period. In this study, we present new ²³⁰Th-dated speleothem data from northern Italy compared with wider North Atlantic paleoclimate records. Our findings reveal that interglacial conditions initiated in subtropical latitudes approximately 424.7 ± 3.3 thousand years (kyr) before present, coinciding with the first, weak insolation maximum during the MIS 11c, while northern high latitudes remained glaciated, with sea levels approximately 50 meters below present. Around 16.1 ± 4.1 kyr after the early subtropical onset, the world experienced peak interglacial conditions, marked by a global sea level rise of 6–13 meters above present levels, despite the persistently weak insolation forcing. We attribute the intense climate response to an exceptionally prolonged period of poleward heat flux lasting approximately 16 kyr prior to the MIS 11c optimum from low latitude, hence shedding light on the complex interplay between insolation variability and climatic responses during this period.