FILLING THE SOUTHERN OCEAN CIRCULATION GAP: INSIGHTS FROM THE KERGUELEN PLATEAU
We present a new neodymium (Nd) isotope record (143Nd/144Nd ratios) from the upper Eocene to lower Oligocene section of ODP Site 748 (Kerguelen plateau, Indian Ocean). Nd isotope ratios provide a useful means to monitor Indian/Atlantic and Pacific Ocean water mass communication through Southern Ocean gateways. We assess our results from the Kerguelen plateau (Indian Ocean) with existing Nd isotope ratio datasets, including those from Maud Rise, Agulhas Ridge, western Tasmanian Margin, East Tasman Rise, and Hikurangi Plateau, in order to determine the timing of mass water mixing in the Southern Ocean. These results are interpreted within the context of a refined tectonic reconstruction of the Southern Ocean, which incorporates the well-constrained history of seafloor spreading in the South Pacific, the Southern Ocean between Australia and Antarctica and an updated model of the Scotia Sea. Our results provide new insights into the Cenozoic evolution of Southern Ocean circulation, and can be used in the validation of high-resolution climate simulations.