Onset and modifications in intensity and pathways of water mass exchange between the Southeast Pacific and the South Atlantic with focus on the Falkland Plateau

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The opening of Drake Passage and the Scotia Sea enabled the exchange of water masses between the southern Pacific and the South Atlantic. In this way heat and energy could be transferred between the two oceans. Together with the opening of the Tasman Gateway this allowed the establishment of the Antarctic Circumpolar Current (ACC) thermally isolating Antarctica, which has been considered as one of the major causes for the onset of widespread glaciation. Both tectonic movements within Drake Passage and the Scotia Sea as well as modifications in climate have led to changes in intensity and pathway of the ACC and the water masses flowing within it. The onset of the ACC and those changes have been documented in sedimentary structures deposited on the Falkland Plateau. A study of the sediment drifts shaped by Circumpolar Deepwater, Weddell Sea Deepwater and Antarctic Bottomwater using high-resolution seismic reflection data collected during cruise MSM81 with RV Maria S Merian provides information on modifications of the circulation resulting from tectonic movements and changes in climate. Additionally, the data are used as site survey data for an IODP proposal set on studying the earliest phase of water mass exchange via Drake Passage.