[H-QR04] Deep time perspective on the geological response to climate change

[HQR04-05] Ventilation Changes in the Northwestern Pacific During the Glacial Period: Evidence in the Core YK15-01 PC13

*Wei-Cheng Hsiung^1,2、Hui-Ling Lin²、Horng-Sheng Mii³、Ken Ikehara⁴、Takuya Itaki⁴、Yuan-Pin Chang² (1.Department of Earth and Planetary Sciences, Kyushu University, Japan、2.Department of Oceanography, National Sun Yat-sen University, Taiwan, R.O.C.、3.Department of Earth Sciences, National Taiwan Normal University, Taiwan, R.O.C.、4.Geological Survey of Japan, AIST, Japan)

キーワード：thermohaline circulation, ocean ventilation, Last Glacial Maximum, Pacific Meridional Overturning Circulation, Heinrich stadial 1, Younger Dryas

In large-scale ocean circulation, the thermohaline circulation controls the exchange of seawater, heat, nutrients, and gas within the ocean and with the atmosphere. In the ocean basin scale, the meridional overturning circulation is a part of global thermohaline circulation. The evolution and change of its strength not only affect ocean circulation all over the world, but also deeply relate to regional climate change. In this study, we estimated the ventilation rate in the western subtropical Pacific based on radiocarbon activity in foraminifera preserved in marine sediments for the Last Glacial Maximum. In comparison with the Atlantic, the Pacific Meridional Overturning Circulation (PMOC) attracted less attention due to the absence of deep water sinking in the North Pacific. This scenario might differ during the Glacial period, making the Northwestern Pacific a candidate for affecting deglacial atmospheric carbon dioxide change and climate change. Our data shows that the ventilation in the subtropical western Pacific was enhanced during the Heinrich stadial 1 and the Younger Dryas. More data will be obtained in the mid-latitude and subarctic Northwestern Pacific to confirm the interpretation of northern-sourced better-ventilated water during the last deglaciation.