142 publications from this institution
No abstract is provided for this article.
The late Pleistocene Holocene stratigraphic architecture on the northeastern Brazilian continental shelf off the Parnaíba Delta has been explored by high-resolution seismic profiles. The seismic surveys reveal the widespread distribution of incised valleys of different size in offshore continuation of the present-day Parnaiba delta. According to morphology two channel types can be distinguished: U-shaped channels in the eastern part and V-shaped channels in the western part. The stratigraphic successions were grouped into four seismic units separated by different seismic boundaries. The characteristics of the seismic boundaries and internal reflectors of the seismic units were used to distinguish between marine and riverine deposits. The incised-valleys architectural elements were used to link sedimentation processes and variations in base level from late Pleistocene channel avulsion and channel infill in the lowermost course of the paleo-Parnaíba River to marine sediments of the present-day inner shelf. The change of the depositional environments in relation to deglacial sea-level rise is compared to incised valley infills of the Mekong River and Red River systems in Southeast Asia.
Investigations of sediment dynamics and geomorphological changes on seasonal and annual scales have been carried out in two different sandy nearshore areas of the southern Baltic Sea. A new method called `tracer stick method' was applied to collect data, about erosion and accumulation to an accuracy of centimeters. On a seasonal basis there is a geographical variation of maximum erosion and deposition values, with the zone of maximum mobility shifting towards offshore during the stormy winter period. At both investigated areas the high sediment mobility does not automatically result in conspicuous morphological changes.
On sait que le succès d’une opération de rechargement des plages dépend en grande partie de la taille des matériaux mis en place. L’auteur expose la méthode utilisée pour arriver à une meilleure compréhension des mécanismes de l’évolution après le rechargement dès lors qu’une grande partie du matériel s’est échappé vers la mer moins d’un an après l’opération. Le suivi, qui repose sur l'utilisation de traceurs, sur des prélèvements d’échantillons de sable et leur tamisage systématique, montre que les sables les plus fins fuient en grand nombre selon des directions très localisées correspondant à l’existence de courants d’arrachement lors des tempêtes. Par temps calme, les barres qui existent dans les petits fonds (la Baltique n’a qu’un très faible marnage) se reconstituent mais du fait de la taille des sables, le bilan est actuellement négatif. Ceci explique le caractère nécessairement répétitif des rechargements.
Die geologisch / sedimentologische Ausbildung des Meeresbodens bestimmt neben der Exposition eines Kustenabschnittes und der Nahrstoffzufuhr masgeblich die Abundanz von Zoo- und Phytobenthos. Die Zielsetzung dieses Projektes war es, die sedimentologische Beschaffenheit des Meeresbodens seewarts des Brodtener Ufers mittels hydroakustischer Messsysteme in einem ausgewahlten Areal flachendeckend zu erfassen und die Ergebnisse in einer Karte darzustellen. Weiterhin sollte eine Zusammenstellung von bereits im Institut fur Geowissenschaften der Christian-Albrechts-Universitat zu Kiel (IfG) vorhandener Seitensichtsonar-Daten aus der Lubecker Bucht erfolgen.
No abstract is provided for this article.
The Late Quaternary history of the Baltic Sea is marked by a complex sequence of glacial lacustine and marine phases (late Pleistocene Baltic Ice Lake Yoldia Like Ancylus Lake Littorina Sea) Boomer data acquired in October 2004 permitted to improve the knowledge of the late Quaternary geological evolution of Tiomper Wick a semi enclosed bay located in the north-eastern part of Rugen Island The sedimentary deposits can be subdivided in 6 seismic units (U1 to U6) The upper part of the lowest unit (U1) corresponds to Pleistocene till Channels incise the top of this till (surface S2) probably created during the fist drainage of the Baltic Sea during the 1 ate Glacial Subsequent channel filling (U2) occurred in two phases beginning with chaotic deposits probably fluviatile of origin followed by graded deposits This filling was stopped by an erosive period with the formation of surface SI showing channels at the same location as S2 The facies of the channel filling (U3 and U4) during a second phase is similar to the first one but resembles a prograding sediment body intercalated between the two units in the shallower part U3 shows a bar shaped deposit at its top The facies of U4 is very similar to a barrier/back barrier facies similar to the facies of unit U5 partly composed of gravel The deposits of U6 correspond to the post Littorina Sea deposits The presence of gravel is linked to coastal cliffs in which chalk layers pushed up by glaciers alternate with sections of till and meltwater deposits and with submarine outcrops of till Gravel deposits are present in unit U5 They tie strongly linked to the presence of a barrier Four of the six units show a barrier facies (U2 U3 U4 and U5) gravel deposits could be present inside all of these units and would represent a larger deposit than estimated previously
