[M-GI28] 地球掘削科学

[MGI28-P03] Identification of a Hyperthermal Event During the Paleocene: IODP Exp. 39

*Suhyun Kim¹、Kiho Yang^1,2 (1.Department of Oceanography, Pusan National University、2.Institute for Future Earth, Pusan National University)

キーワード：IODP, South Atlantic Transect, ELPE, Clay minerals

The Paleocene epoch was characterized by globally higher temperatures compared to the present, with several hyperthermal events occurring during this period. The Paleocene-Eocene Thermal Maximum (PETM), which occurred around 55.8 Ma, is the most prominent hyperthermal event. Another hyperthermal event, predating the PETM at approximately 58.4 Ma, is the Early Late Paleocene hyperthermal Event (ELPE) or the Mid-Paleocene Biotic Event (MPBE). The ELPE has also been identified in sediment samples from Hole U1556A (243.78 mbsf, ~61.2 Ma) collected during South Atlantic Transect IODP Expedition 390 (April 7 – June 7, 2022). This study aims to investigate environmental changes during the ELPE in the Paleocene from a mineralogical perspective and to identify changes in sediment sources. Sediments corresponding to the ELPE are characterized by a relative increase in clay content, resulting in a dark brown color due to the dissolution of calcareous sediments. The identified sedimentary minerals include clay minerals, quartz, feldspar, and calcite. During the ELPE, the total clay content reached up to 70 wt.%. Additionally, increased quartz and feldspar contents during this period suggest wind-driven sediment transport. The ELPE coincides with a maximum in eccentricity cycles, indicating the potential influence of Milankovitch cycles on marine environmental changes. Therefore, clay mineral analysis could provide valuable insights into sediment source and contribute to understanding the relationship between sedimentary changes and Milankovitch cycles.