Reconstructing North Atlantic Deep Water Variability Under Pliocene Warm Climates: Evidence from IODP Site U1564

Authors: Megan Lewis, Halima Ibrahim

Field of Study: Science, Technology, Engineering, and/or Math

Faculty Mentors: Molly Patterson

Easel: 107

Timeslot: Afternoon

Abstract: The early–mid Pliocene (~5.3–3 Ma) represents a key warm interval in Earth’s climate history, preceding major Northern Hemisphere glaciation. Past proxy and model studies suggest that the Atlantic Meridional Overturning Circulation (AMOC) was stronger during these warm intervals, potentially amplifying global heat transport (e.g., Raymo et al., 1996; Zhang et al., 2021). Using sortable silt grain-size measurements and ln(Zr/Rb) ratios, variations are reconstructed in ISOW vigor across two major warm intervals: the Pliocene Climate Optimum (~4.4–4 Ma) and the mid-Pliocene Warm Period (~3.3–3 Ma). These data provide the first high-resolution velocity reconstructions from the Gardar Drift for this interval, revealing shifts in deep-water export from the Nordic Seas and the behavior of AMOC under sustained warm climate conditions. The results clarify the sensitivity of NADW formation during past warm periods and offer a paleoceanographic framework for evaluating potential future changes in AMOC strength.