The world oceans are a major component of the Earth System, and changes in the complex global ocean current system are likely to cause global environmental changes. On geological time-scales, these water mass exchanges are controlled by the deepening and shallowing of areas of ocean floor during the tectonic opening and closing of strategic oceanic gateways and the formation of ocean basins. Establishing the detailed tectonic, geodynamic, sedimentary and paleo-topographic histories of strategic oceanic basins and gateways will provide the essential framework for modelling studies that will relate these events to paleo-climate observations collected across the globe. PLATES & GATES intends to adopt a multidisciplinary approach by addressing tectonic-magmatic, geodynamic, sedimentary and biostratigraphic processes, by utilising paleo-biological and geochemical proxies as well as past and recent oceanographic conditions in the gateways, and by using state-of-the-art geophysical techniques, sediment coring, ocean drilling and accompanying land investigations. The main objectives include (1) studies of the crust/lithosphere of the polar ocean basins and polar gateways as well as their continental margins to develop a good understanding of the past and present plate kinematics, mantle processes, margin formations, and crustal subsidence and uplift processes, (2) understanding the past ocean current systems in the basins and gateways by examining the record of change preserved in deep-ocean sediment deposits and drifts, and by undertaking seismic-stratigraphic investigations and analyses of present and paleo-oceanographic proxies to derive the evolution of deep-water circulation and climate change, (3) reconstructing detailed ocean basin and gateway opening processes and constraining the timing of shallow and deep water mass exchange between basins, (4) understanding the long-term paleo-climatic history from Mesozoic-Early Tertiary Greenhouse conditions to upper Tertiary-Quaternary Icehouse conditions, and (5) identifying and modelling the role of gateway openings/closures in the global carbon cycle, bio-evolution and the development of ice-sheets and climatic changes.PLATES & GATES will perform Cenozoic and Mesozoic 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 new paleo-bathymetric reconstructions arising from the new data acquisition described above. The results from these experiments will be 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 polar and global climates over long geological timescales.
AWI Organizations > Geosciences > Marine Geology and Paleontology
Helmholtz Research Programs > MARCOPOLI (2004-2008) > MAR1-Decadal Variability and Global Change