09:30 〜 09:45
[MIS15-03] 南太平洋Campbell Plateauの海底堆積物から復元した古第三紀前期温室地球における超温暖化イベントの化学的特徴
キーワード：古第三紀、国際深海科学掘削計画、超温暖化、暁新世-始新世境界温暖化極大、南太平洋
During the early Paleogene, Earth’s mean surface temperature was considerably higher than at present day, which is recently described as “Hothouse” climate state in the Cenozoic era [1]. Superimposed on the millions-of-years global warmth, multiple transient global warming events occurred. These early Paleogene “hyperthermals” are commonly characterized by rapid and distinct negative carbon isotope (δ13C) excursions in both terrestrial and marine realms, suggesting massive injections of 13C-depleted greenhouse gas(es) into the ocean-atmosphere system.
International Ocean Discovery Program Expedition 378 “South Pacific Paleogene Climate” was conducted from January to February 2020. One of the major targets of this expedition was to recover a continuous sedimentary sequence including the early Paleogene hyperthermals [2]. In this study, we investigated Holes U1553C and U1553D, drilled at ~1,222 meters of water depth on the southern Campbell Plateau, south of New Zealand [2]. We analyzed major- and trace-element compositions, δ13C, δ18O, and CaCO3 contents for 364 bulk carbonate samples. The downhole δ13C profile clearly demonstrates multiple negative excursions corresponding to the Paleocene-Eocene Thermal Maximum (PETM), the most prominent environmental perturbation in the early Paleogene, and other modest hyperthermals such as the Eocene Thermal Maximum (ETM) 2 and ETM3. In the presentation, we will discuss multi-elemental features of the bulk sediment composition and their time-series variations during the studied interval.
[1] Westerhold et al. (2020) Science 369, 1383-1387. [2] Röhl et al. (2022) Proceedings of the IODP. 378.
International Ocean Discovery Program Expedition 378 “South Pacific Paleogene Climate” was conducted from January to February 2020. One of the major targets of this expedition was to recover a continuous sedimentary sequence including the early Paleogene hyperthermals [2]. In this study, we investigated Holes U1553C and U1553D, drilled at ~1,222 meters of water depth on the southern Campbell Plateau, south of New Zealand [2]. We analyzed major- and trace-element compositions, δ13C, δ18O, and CaCO3 contents for 364 bulk carbonate samples. The downhole δ13C profile clearly demonstrates multiple negative excursions corresponding to the Paleocene-Eocene Thermal Maximum (PETM), the most prominent environmental perturbation in the early Paleogene, and other modest hyperthermals such as the Eocene Thermal Maximum (ETM) 2 and ETM3. In the presentation, we will discuss multi-elemental features of the bulk sediment composition and their time-series variations during the studied interval.
[1] Westerhold et al. (2020) Science 369, 1383-1387. [2] Röhl et al. (2022) Proceedings of the IODP. 378.