Paleobathymetry of the Southern Ocean and its role in paleoclimate variations

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The Southern Ocean hosts the worldwide largest and most dynamic ocean circulation system affecting global climate variations in a major extent. Understanding past Southern Ocean circulation processes help decipher present observations of changing oceanic parameters and help improve predictions of climate variations. By developing a unified Southern Ocean digital stratigraphy from the conjugate continental shelves to the abyssal plains, this project is aimed to generate series of paleobathymetric grids of times that are critical for understanding paleo-ocean circulation and climatic changes at long time-scales. A selection of suitable DSDP, ODP and IODP drill sites as well as the large network of existing seismic lines will serve as the key datasets for stratigraphic constraints. The Southern Ocean paleobathymetric grids, in which newest plate-kinematic models, lithospheric subsidence parameters and models of dynamic mantle topography are incorporated, will be used to simulate paleoceanographic and paleoclimate scenarios with particular emphasis on the opening of Southern Ocean gateways, the development of topographies along spreading ridges, fracture zones and oceanic plateaus as well as the water mass generation and ocean current dynamics along the continental shelves, slopes and rises. The ultimate aim of the project is to generate Cenozoic climate reconstructions using a variety of Earth system models designed to evaluate the effect of ocean gateways and basins on paleo-circulation patterns, the global carbon cycle and nature of polar ice sheet development. These experiments will include sensitivity runs incorporating the new paleobathymetric and paleotopographic reconstructions. The results from these experiments are compared with other model simulations, which include different forcing factors such as atmospheric greenhouse gasses and mountain uplift to determine the relative importance of paleo-geography on the evolution of global climates over long geological timescales.