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Ruland M., Wartenberg W.. Geologische Untersuchungen im Bereich der ehemaligen Oberahnschen Felder (östlicher Jadebusen). 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. 155-166. EUCC-D - Die Küsten Union Deutschland e.V., Rostock, 2011.

Zusammenfassung: The “Oberahnschen Felder” were former marsh islands within the northeastern part of the Jade Bay, southern North Sea, Germany. Their destruction due to tidal erosion was completed at the latest in the middle of the last century. Cartographically they are not listed anymore from the year 1952 onwards.Based on the question whether there still are geologically detectable remains of the former marsh islands a core with a total length of 6 m was sunk in this area at low tide using a double pipe drilling method. The core was analysed using optical-haptic as well as sedimentological and diatomological methods and interpreted in terms of lithology and genesis. The probe did not penetrate the base of the Holocene coastal sequence. The core’s chronostratigraphic framework so far remains unclear due to a lack of material to be dated by the radiocarbon method. Optically stimulated luminescence was not undertaken.The tidal sediments gained predominately identify sandy flat deposits to silt-dominated mixed flats. In the upper part of the core, at 0.83 to 2.49 m beneath top ground surface, the silty strata may be interpreted as representing brackish water deposits showing vertical Phragmites-rootlets. This sequence is understood to match the brackish facies described by Schütte for his sedimentological profiles of the former marsh islands during 1927 and 1937. Up to a depth of 4 m, the underlying strata image a palaeoenvironment being in close vicinity to shoreline erosion areas, with layers of sediments being strongly enriched by reworked finest peat. However, the former marshlands cannot be proven geologically in this core. Diatom analyses were carried out at 2.20 to 3.90 mwithin brackish and marine deposits, which are partly humiferous. Within this sequence, marine diatom species are dominant. Poor preservation and large amounts of destroyed and reworked diatom frustules point to transport and high energy hydrodynamic processes. The determination of small, strongly silicified and therefore relatively stable autochthonous species mimic a palaeoenvironment that is characterized by sandy tidal flats in the vicinity of the core.
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