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Sedimentary facies of glacial-interglacial cycles in the Norwegian Sea during the last 350 ka

1989; Elsevier BV; Volume: 86; Issue: 4 Linguagem: Inglês

10.1016/0025-3227(89)90090-x

1872-6151

Rüdiger Henrich, Heidemarie Kassens, E. Vogelsang, Jörn Thiede,

Isotope Analysis in Ecology

Sediment fluxes were highest in the Norwegian Sea during late glacial/early deglacial periods, i.e., at oxygen isotope transition 43, below transition 65, at various levels within stage 6, and below stage 9. Dark diamictons deposited at these times reflect intense iceberg rafting in surface waters fed by surges along the front of the marine-based parts of the continental ice sheets in the southeastern sector of the Norwegian Sea. The high organic carbon content (0.5–1.3%) in these layers reflects input from erosion of terrigenious matter-rich sediments outcropping on the shelves. Partial oxidation of organic matter and decreased deep-water renewal may explain the strong carbonate dissolution observed during these periods. Interglacial environments were strongly variable throughout the last 350 ka. Circulation patterns of stage 5e best resemble modern conditions, while stage 7 and 9 sediments record a much weaker Norwegian Current.