Quaternary Paleoceanography of the Arctic Gateway Region Based on Isotopic and Faunal Analysis of Foraminifera

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9423485 Flower This award supports a project to study sediments from the Arctic Gateway region. Surface water exchange through the Arctic Gateway at Fram Strait accounts for about 90% of the Arctic heat budget and so this region may have played a major role in glacial-interglacial Arctic climates during the Quaternary. The major objectives of this research include documenting the Quaternary history of Arctic climates and investigating the role of surface to intermediate water exchange through the Arctic Gateway in late Quaternary glacial-interglacial Arctic climates. Two sedimentary sequences on the Yermak Plateau, recently drilled by Leg 151 of the Ocean Drilling Program, provide the first opportunity for high-resolution studies of the Arctic Gateway region. This project will generate high-resolution isotopic and faunal records based on planktonic and benthic foraminifera from sites 910 and 911 forming a depth transect on the Yermak Plateau (at 556 and 902 m water depth, respectively). Planktonic records, with about 4,000 year resolution, will be spliced together from both sites to form a composite record of surface water environments throughout the Brunhes Epoch (late Quaternary to present). Benthic records, with about 10,000 year resolution, will also be compiled. When combined, these records will allow detailed comparison of surface waters to intermediate water environments for areas with 550 and 900 m water depths. These data will allow detailed reconstruction of surface to intermediate water hydrography during the Brunhes Epoch. Extended records at site 911A will provide the first long-term, high-resolution records of Arctic surface and intermediate water environments throughout the Quaternary. These hydrographic interpretations of the integrated isotopic and faunal records will test hypotheses about the role of this oceanic gateway in regional and global climatic change. The results will bear on the importance of meridional heat transport by Arctic Gateway surface currents during intervals of global warmth and during important climatic transitions. The intervals of greatest interest include the mid-Quaternary climatic transition from about 1.2-0.6 Ma, and glacial-interglacial cycles of the Brunhes Epoch. The records obtained will greatly improve our understanding of the influence of the Arctic Gateway region on the global climate system during the Quaternary. In particular, this work will examine the role of Arctic Gateway paleoceanography in the Quaternary glacial evolution of the Northern Hemisphere. Lastly, it should provide insights into the future response of Arctic climates to projected global warming.