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| Deloffre, J; Verney, Romaric; Lafite, R; Lesueur, P; Lesourd, S; Cundy, A. |
| The objective of this study is to propose an original approach to the analysis of the formation of intertidal rhythmites, their preservation, and the evaluation of sedimentation rates on estuarine mudflats. Three mudflats, one from each of three estuaries, were analysed using a combination of long-term (>a year), high-frequency (1 burst/10 or 20 min), and high-resolution (0.2 cm) altimeter datasets and X-ray images of sediment cores collected during topographic surveys. The results highlight the roles played by sediment supply, hydrodynamics, and morphology of the lower estuaries on the sedimentation rhythms. While the sediment-starved Medway estuary (Kent, UK) remains stable at different time-scales, the annual sedimentation rates on the sheltered... |
| Tipo: Text |
Palavras-chave: Macrotidal estuary; X ray imagery; Altimeter; Rhythmites; Mud; Morphology. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3517.pdf |
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| Waeles, Benoit; Le Hir, Pierre; Lesueur, P; Delsinne, N. |
| The mouth of the Seine River estuary (France) has undergone marked morphological evolution over several decades mainly due to engineering works aimed at improving access to Rouen and Le Havre harbours. The intertidal areas are decreasing in size and the lower estuary is accumulating sediment and prograding. In order to understand and better describe the major morphological behaviours of the estuary, a morphodynamic numerical model was developed within the Seine-Aval program. At the end of the 1st part of the research program, a validated fine sediment transport model (3D) was available (Le Hir et al., 2001b). As the present morphological study addresses medium-term issues (a few decades), and because of the need to investigate impacts of local structures... |
| Tipo: Text |
Palavras-chave: Sand and mud mixtures; Sediment transport modelling; Morphodynamics. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-7404.pdf |
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| Dubrulle, C; Jouanneau, J; Lesueur, P; Bourillet, Jean-francois; Weber, O. |
| The study area, "La Grande Vasiere" (LGV), stretches out on the French Atlantic continental shelf (at ca. 100 m water depth), along 250 km from the Glenan Islands at the north to the southwest of Rochebonne at the south. Box-cores were sampled in this mid-shelf area during four cruises in June 1995, and in April, June and September 2002. They were investigated using sedimentologicat approaches (X-radiographs and grain-size analyses) and radionuclide studies (Pb-210 geochronology and excess Th-234). The main results are: (1) the surficial sediments are generally organized into a decimetrescale fining up sequence which can be the result of extreme storms; (2) an upper mixing layer of 7-20cm reflects an important biological benthic activity and/or the impact... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Continental shelf; Sedimentation rate; Radionuclides; Fine sediment fraction; Mud. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3539.pdf |
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