Sr-Nd isotopes and clay mineralogy on the South Indian Ridge: evidence of stronger equatorward export of AABW during Heinrich Stadial 1 and 2

• Main Authors: Francois, Beny, Bout‑roumazeilles, Viviane, Davies, Gareth
• Other Authors: Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD France-Nord ), Faculty of Earth and Life Sciences Amsterdam (FALW), Vrije Universiteit Amsterdam Amsterdam (VU)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDE]Environmental Sciences; [SDU]Sciences of the Universe [physics]; [SDV]Life Sciences [q-bio]; [PHYS]Physics [physics]; Antarctic; Indian; Kerguelen; Antarc*; Antarctica
• Online Access: https://hal.archives-ouvertes.fr/hal-02348813

International audience The evolution of Antarctic Circumpolar Current (ACC) and Antarctic Bottom Water (AABW) remains controversial. In this study, we aim to quantify this evolution by studying the trace and rare earth elements, and Sr-Nd isotopes of clay mineralogy during the last deglaciation on fine grain detrital sediments (<2µm) from the sediment core MD12-3396Cq recovered East of the Kerguelen Plateau. Sediment composition represent a mix between sediments from the Kerguelen Plateau and from Antarctica. Overall, the Kerguelen Plateau is the dominant source of sediment, supporting the idea that the ACC is the most important current bringing sediment to the site. Provenance proxies also show that the contribution of Antarctica was higher than previously thought, reaching 30% during Heinrich Stadial (HS) 1 and 2. We propose that the delivery of sediment from Antarctica is made by the AABW via the Deep Western Boundary Current (DWBC) flowing northward along the Kerguelen Plateau. The higher contribution of AABW during HS 1 and 2 suggests that the DWBC was stronger than during modern interglacial period, and generated enhanced export of the AABW to the Global Ocean via the Deep Western Boundary Current.