Sortable silt analyses on IODP Expedition 382 Scotia Sea sites

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The sedimentary record of the Scotia Sea keeps the information of the major Antarctic Ice Sheet oscillations, variability in the oceanographic pattern of the Southern Ocean and main regional tectonic events. Three sites were drilled in the Scotia Sea during the International Ocean Drilling Program (IODP) Expedition 382. IODP Expedition 382 sites recovered an almost continuous record between late Miocene and present day, in two distinguished basins of the Scotia Sea located to the south and to the north of the South Antarctic Circumpolar Current Front. In this time frame, major changes in the oceanographic pattern were triggered by the global climatic variability and the oscillation of the Antarctic Ice Sheet. Thus, the changes on the speed of bottom flows would reflect changes in the environmental conditions with major impacts on the Global Thermohaline Circulation and by extension on the Earth climatic system. I propose to perform systematic sortable silt analyses on discrete sediment samples from the IODP Expedition 382 sites recovered in the Scotia Sea. Fine grain-size distributions derived from sortable silt analyses have been widely used to infer palaeoflow speeds at the time of sedimentation. Combination of the sortable silt results with regional seismo-stratigraphic studies will provide the reconstruction of bottom current paths and velocities in the Scotia Sea and their variability through time. This will allow the reconstruction of the oceanographic pattern of the Scotia Sea and the Drake Passage, and how its variability relates to the Antarctic Ice Sheet evolution. Overall the proposed research will allow comparison between bottom-current sorting, ice-rafted sedimentation and ice sheet dynamic behaviour. Results of the proposed study would reveal the evolution of the oceanographic pattern and its link to the Antarctic Ice Sheet evolution, involving global climatic implications.