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Tillmann T., Wunderlich J.. Genese eines Strandhakens am Beispiel der Hörnum-Odde (Süd-Sylt) – Untersuchungen des oberflächennahen Untergrundes durch die Kombination von geophysikalischen und sedimentologischen Methoden. In: Karius V., Hadler H., Deicke M., von Eynatten H., Brückner H. & Vött A.. Dynamische Küsten - Grundlagen, Zusammenhänge und Auswirkungen im Spiegel angewandter Küstenforschung. Coastline Reports (17), pp. 177-190. EUCC-D - Die Küsten Union Deutschland e.V., Rostock, 2011.
The aim of this ongoing study is the detection and interpretation of shallow subsurface structures on the German North Sea islands Sylt and Amrum using geophysical and sedimentological data. The main focus of the investigation lies on the reconstruction and comparison of the geological development of the southern barrier spit of Sylt, and the northern part of Amrum during the Holocene. The sedimentary structure and architecture of hese island spit systems were investigated through an integrated approach using ground-penetrating radar (GPR) and sedimentological analyses of shallow sediment cores. GPR data allow high resolution investigation of the shallow subsurface underground. A geophysical Survey Systems Inc. radar system, SIR-2000 coupled with a 100 MHz, 200 MHz and 400 MHz antenna, was used. Maximum penetration depths to 350 ns TWT whichcorrespond to approximate depths of 15 m were reached. GPR surveys were orientated in 2D and 3D survey geometries with individual profile lengths between 30 m and 5 km. The topographic data of the GPR transects were collected by dGPS (Ashtech ProMark II and Topcon GPS G3). The software ReflexWin from Sandmeier Scientific Software was used for editing and processing the GPR data. Different standard processing steps were chosen to increase the signal-to-noise ratio and to improve resolution. Up till now, a total of 38 km GPR transects have been collected on the islands of Sylt and Amrum. To link GPR results with sedimentological data, 7 vibracores that reach a maximum depth of 8 m below the surface were drilled at selected positions along the radar profiles. The combination of cores and high-resolution GPR data allows a detailed facies analysis and provides insights into the complicated sedimentary architecture as well as leads to new theories about the development of both barrier island spits. The comprehensive understanding of barrier island geomorphology is essential for an assessment of the effects of rising sea level associated with global warming. |
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Genese eines Strandhakens am Beispiel der Hoernum-Odde.pdf (7.539.454 Bytes) |
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