Planktic foraminiferal evidence for variation in the strength of the Agulhas Current during the Pliocene (4.6-2.6 Ma)

The Pliocene, although predominantly warm, experienced four major glacial events at 4.8, 4.0, 3.3, and 2.7 million years ago (Ma), altering ice sheet dynamics and ocean circulation. This study reconstructs Agulhas Current (AC) variability using planktic foraminiferal census and stable oxygen isotope data from IODP Hole U1474A. Eleven AC weakening events were identified—five in the Early Pliocene (4.35–3.6 Ma) and six in the Late Pliocene (3.4–2.67 Ma). These coincide with glacial expansions and the growth of the Antarctic Ice Sheet, which likely shifted the polar fronts northward, reducing AC strength and Agulhas Leakage. This weakening may have had a significant impact on global thermohaline circulation during the Pliocene.