Evaluating the Last Glacial Maximum Ice-Sheet Extent in the Northen Kara Sea and its Effect on the Siberian River Drainage.

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Polyak0221468The Principal Investigator will investigate the stratigraphy and morphology of Quaternary deposits in the northern part of the Kara Sea in order to delineate the ice-sheet limits at the Eurasian Arctic margin during the Last Glacial Maximum (LGM). This will test whether voluminous West Siberian rivers were dammed by the ice on the Kara Sea continental shelf and thus, prevented from discharging into the Arctic Ocean.He will conduct a study based on seismic-reflection data, including sparker, subbottom sonar and sidescan sonar records and sediment cores collected from the northern Kara Sea. A pre-evaluation of these data reveals a complex system of glacigenic deposits, riverine networks, extended on the shelf during low sea level and proglacial/prodeltaic basins. A detailed investigation of these data, preferably supplemented by additional transects to be run in 2003, and their comparison with glacial-geological results from adjacent land areas will allow them to answer whether the Barents-Kara ice sheet expanded across the entire northern Kara Sea during the LGM.This study will involve processing and interpretation of seismic-reflection records, construction of detailed digital bathymetric and seismo-stratigraphic models and determination of age and depositional environments of sediment-core material. The resulting products will include stratigraphically-controlled, three-dimensional terrain models or morainic deposits, adjacent depositional basins, and major paleo-river channels. Sidescan data will provide additional information on seafloor texture. These results will provide necessary boundary conditions for modeling the paleohydrology of the Eurasian Arctic for the last glacial cycle. Generated data on the configuration of the ice-sheet margin and the distribution of glacigenic erosional and sedimentary features will help understand the patterns of glacial development in northern Eurasia and the potential role of ice shelves in the Arctic Ocean. In addition, generated bathymetric grid models will improve the international bathymetric data base for the Arctic.