EFFECTS OF ICE COVERAGE AND ICE-RAFTED MATERIAL ON SEDIMENTATION IN THE FRAM STRAIT

AS little is known about pelagic sedimentation processes in Arctic environments 1, the interpretation of biological and chemical processes, as well as the reconstruction of ancient conditions, including those in the glacial North Atlantic, is difficult. Here we provide sediment-trap results, which show that the position of the sea-ice boundary significantly influences the particle flux. The seasonal variability of the particle flux differed markedly in the various sediment-trap sites in Fram Strait, depending on the behaviour of the sea ice. Under complete ice cover, sedimentation is very low, whereas maximum sedimentation is found at the ice margin. The highest particle flux observed, showing a large lithogenic component, was observed at the ice edge where the water was warmer (> 2-degrees-C). We find that high biogenic opal fluxes are characteristic of the summer ice margin, indicating that the sedimentary record of opal fluxes may allow the position of ice margins in the past to be reconstructed.