Shore-Connected Large-Scale Bed Forms in Køge Bugt, Western Baltic, Denmark

ABSTRACT

Sediments and morphology of large-scale bed forms in the offshore zone (depth:–2 to–8 m) situated in the western Baltic, just south of Copenhagen, have been investigated by means of airphoto interpretations and diving observations.

The bed forms appear as isolated stripes on the sea bottom, are more than 1 km long, 50–200 m broad, but only 0.2-0.3 m high and run almost normal to the shoreface. It was found that, although asymmetrical, the stripes show no evidences of netmigration for the last 35 years. They consist of homogeneous fine-sand, and rest upon smooth, glacial drift materials partly covered with lag sediments. Geometrically, the large-scale bed forms can be classified as sand ribbons, but from a dynamical point of view, they can hardly be explained as longitudinal current bed forms.

On the basis of the local wave and current environment some possible interpretations of the bed form origin are discussed.