Recent sediment accumulation in the Norwegian Channel, North Sea
Abstract
In the Norwegian Channel 35 box cores were taken for sedimentological analysis, and 210Po a- and137Cs y-spectroscopy to determine sedimentation rates. Grain sizes were determined and X-ray photographs of the cores were made, in addition, penetrating echo sounding lines covering a length of more than 5500 km were studied. Sediments enter the Norwegian Channel from the south and the west as suspended load. The dry bulk densities of these generally fine-grained sediments (silty clays-silts) range from 0.35 to 1.79 gxcm3. Most of the cores show a surface mixed layer of less than 2 cm. The sedimentation rates measured in the Norwegian Channel range from 30 to 280 mmx100yr. Highest sedimentation rates are found in the northern part of the research area. The contrast between the present-day relatively high sedimentation rates and the thin Holocene sedimentary units is explained by a change in the depositional system sometime during the Holocene.