15:00 〜 15:15
[MIS17-30] 後期中新世から更新世における南大洋の気候とダスト、生物生産のカップリング
キーワード：気候変動、表層海水温度、後期新生代、ダスト、生物生産、南大洋
Dust potentially affects global climate via the direct and indirect effect on radiative balance of the atmosphere and by supplying essential limiting micronutrients such as iron to the ocean. In fact, supply of dust to the Southern Ocean increases during the glacial periods of the late Pleistocene may have contributed to the decrease in concentration of CO2, suggesting strong coupling of climate, dust and productivity in the subantarctic Southern Ocean during the Pleistocene. However, link among the climate, dust and productibity in earlier times and its role in the evolution of the long-term climate since the late Miocene have remained unclear. Here we report long-term record of SST, dust and productivity in the Southern Ocean over the past 10 million years based on the analysis of marine sediments from ODP Site 1123, South Pacific sector of the subantarctic zone. Our new records show strong coupling of climate, dust and productivity over the past 10 million years with increase in dust and productivity during cold glacial periods including the late Miocene cooling (6-7 Ma). This finding suggests that the Southern Ocean played a key role in drawdown of atmospheric CO2 level during the late Miocene.