Circum-Antarctic Stratigraphy and Paleobathymetry: Development of Grid-based Simulations

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Paleoceanographic models of the Southern Ocean suffer from missing boundary conditions which describe accurately the geometries of the seafloor surfaces at their geological epoch and their dynamics over long time-scales. This results in uncertain estimates of the onset and paleoclimate consequences of the deep-water openings of the Drake Passage and the Tasmanian Gateway. The development and implications for deflections of major deep-sea current systems, e.g. the Antarctic Circum-Polar Current (ACC), through structural obstacles such as oceanic plateaus and ridges is also not described due to lacking reconstructions of their bathymetric growth. As the reconstruction of the changing sediment cover is the largest missing component for accurate paleobathymetric models, a unified circum-Antarctic digital stratigraphic grid from continental shelves to the abyssal plains will be generated in this project by integrating the large seismic data basis of the Antarctic Seismic Data Library System (SDLS) and data from international cooperation partners as well as drill information where available. This grid will then be used to calculate a series of circum-Antarctic paleobathymetric grids in which newest plate-kinematic models, lithospheric subsidence curves and models of dynamic mantle topography are incorporated. Finally, paleoceanographic and paleoclimate scenarios will be simulated using this paleobathymetric grid with particular emphasis on the opening of the Drake Passage and Tasmanian Gateway and the paleo-current dynamics along the continental shelves, slopes and rises.