Publication Abstract

Genesis and sediment dynamics of a subaqueous dune field in Fehmarn Belt (south-western Baltic Sea)

Genesis and sediment dynamics of a subaqueous dune field in Fehmarn Belt (south-western Baltic Sea)

P. Feldens, K. Schwarzer, C. Hübscher, M. Diesing*

A subaqueous dune-field, consisting of large scale bedforms, is located in Fehmarn Belt, south-western Baltic Sea. These bedforms have been investigated several times but their genesis and recent dynamics is not completely understood yet. Application of high-resolution hydroacoustic methods allows further insight into the development and dynamics of these structures. An area of approximately 75 km² has been mapped in full coverage with a multibeam echo sounder. Additionally, 40 nm (nautical miles) of high-resolution shallow water seismic profiles (parametric echo sounder and boomer-system) have been recorded. The subaqueous dune-field is situated in water depths of about 11 to 25 m, with an extension of about 8.1 km E – W and 1.8 km N - S. It consists of asymmetric dunes with crest-heights of up to 2.5 m. The sediment of the subaqueous dune-field is composed of allochthonous, well sorted medium to coarse sand, forming a sediment layer of up to 4.5 m thickness. Sand ribbons, connected to the subaqueous dune-field and protruding from the field towards south-west, are supposed to be sediment-conduits. Based on repeated bathymetrical mappings during a 1.5 years period, no movements of the dune crests have been observed in the central part of the subaqueous dune-field. However, compared to older maps an increase in the spatial extension of the subaqueous dune-field towards west and southwest has been observed due to newly formed bedforms. It is assumed that sediment movements in the subaqueous dune-field occur mainly during west-storm conditions, when salt water intrudes from the North Sea into the Baltic Sea.

Reference

P. Feldens, K. Schwarzer, C. Hübscher, M. Diesing* (2009) Genesis and sediment dynamics of a subaqueous dune field in Fehmarn Belt (south-western Baltic Sea) In: Vött, A., Brückner, H. (eds.). Erträge moderner Küstenforschung, Beiträge zur 26. Jahrestagung des Arbeitskreises Geographie der Meere und Küsten, 25.-27. April 2008, Marburg an der Lahn. Marburger Geographische Schriften 145, 80-97.

P. Feldens, K. Schwarzer, C. Hübscher, M. Diesing*

In: Vött, A., Brückner, H. (eds.). Erträge moderner Küstenforschung, Beiträge zur 26. Jahrestagung des Arbeitskreises Geographie der Meere und Küsten, 25.-27. April 2008, Marburg an der Lahn. Marburger Geographische Schriften 145, 80-97.