MULTI-PROXY INVESTIGATION OF THE PALEOCENE-EOCENE THERMAL MAXIMUM AT IODP SITE U1580: NEW INSIGHTS FROM THE SOUTHERN OCEAN

The Paleocene-Eocene Thermal Maximum (PETM, ~56 Ma) is an important model for studying fast climate change, but little is known about how it played out in the Southern Ocean. This study utilizes multiple proxies from IODP Site U1580 (Agulhas Plateau, 40°47.1535′S/26°36.4137′E), integrating foraminiferal geochemistry, assemblage data, and isotope analysis to recreate environmental conditions during the Paleocene-Eocene Thermal Maximum (PETM). Our high-resolution records indicate a diminished carbon isotope excursion (CIE) of around 1.5‰, significantly less than the 2.5-4‰ excursions reported at other geographical locations. Mg/Ca studies of Acarinina coalingensis suggest a sea surface temperature increase of approximately 6°C, aligning with worldwide estimates. A comprehensive examination of bioturbation effects, with computed vertical mixing rates of 90 cm²/kyr, indicates that mixing may attenuate but not eradicate fundamental environmental signals. The integration of δ¹³C, δ¹⁸O, and Mg/Ca records from surface-dwelling Acarinina and thermocline-dwelling Morozovella indicates increased vertical mixing during the PETM at this location. Our findings indicate that the Agulhas Plateau's location at the intersection of significant ocean currents may have influenced the local manifestation of this global climatic disruption, underscoring the significance of regional oceanographic factors on PETM signals.