The North Atlantic-Arctic Gateway: Plio-/Pleistocene Paleoceanography of the Fram Strait and Yermak Plateau (Arctic Ocean)

The Fram Strait is the only deep connection between the Arctic Ocean and the World Ocean and therefore plays a crucial role for the exchange of surface and deep water masses in the high northern latitudes. Relatively warm surface waters that flow from the North Atlantic Ocean along the Scandinavian continental margin into the Arctic Ocean, and cold-ice covered waters that exit the Arctic Ocean through Fram Strait are sensitive elements of the oceanographic system. In particular the variable inflow of warmer waters that influence today the climate of northern Europe had also a considerable impact on the waxing and waning of large ice sheets in the Eurasian Arctic in the past.

In the frame of the Ocean Drilling Program, several boreholes were drilled in the North Atlantic-Arctic Gateway during ODP Leg 151 to reconstruct the paleoceanographical history in the Fram Strait and Yermak Plateau region (Fig. 1). Sites 910 and 911 recovered a complete Plio-Pleistocene sequence and were selected to establish a precisely dated record of the long-term history of surface water exchange between the Arctic Ocean and the Norwegian Sea and the evolution of ice sheets in the Barents Sea region in the past 3.5 million years. Selected time intervals such as the Pleistocene glacial-interglacial cycles, the Mid-Pleistocene climate transition and the Late Pliocene when large continental ice sheets developed for the first time in the high northern latitudes will be analysed at a high resolution to study the relationship between paleoenvironmental change and climate cycles on various time scales.

Time series of paleoenvironmental change will be developed from a range of micropaleontological, sedimentological, mineralogical and geochemical proxies because a single method cannot resolve the complex interactions between various components of the high latitude climate system such as surface and deep water masses, sea-ice cover, supply of freshwater from the adjacent continents and  the build-up and decay of ice sheets. Major emphasis is placed on a combination of non-destructive measurements and analyses on discrete samples to explain the pronounced variability of terrigenous sediment input both with respect to source areas and transport processes.