Postglacial deposition of sand in the Eckernfoerder Bay, western Baltic Sea

At the NW-slope of Eckernforder Bay (Western Baltic) between 14 and 21 m water depth 7 sand cores were taken with a vibrocorer. The cores were between 85 and 250 cm long. The sand was analysed for grain size distribution, proportions of organic carbon and carbonate, and contents of microfossils. The radiometric age and stable carbon isotope ratios were determined on organic material from 14 sample. With regard to benthic foraminifera and other microorganisms four different types of depositional conditions could be distinguished: Types 1 and 2: two types of offshore sand areas. Type 3: lagoon and nearshore. Type 4: subaerial or limnic. Using sedimentological and geochemical parameters two formation areas could be distinguished with the aid of a discriminant analysis: offshore (types 1 and 2) and nearshore (types 3 and 4). A juxtaposition of core sections indicated two distinct profiles. Their ages fit into the picture of the assumed postglacial sea-level rise. The lagoon- and nearshore sands are interpreted as the result of sea-level stagnation at 17-18 m below present sea-level. The accumulation rates of the sand in the offshore areas are, with a maximum of 0.15 mm/yr., an order of magnitude smaller than in the mud areas, located several hundred metres away.