|
|
|
|
|
| Donnadieu, Y; Lecroart, P; Anschutz, P; Bertrand, P. |
| We have constructed a nonsteady state numerical model of organic carbon, aluminum, and uranium burial to examine the dynamic response of sediments to variations on thousand years scale. The three components are defined by distinct behaviors in the sedimentary system. The aluminum is a conservative component, the organic carbon is a nonconservative component degraded in superficial sediment, and the uranium is a component affected by redox conditions. By introducing a simultaneous variation of incoming fluxes of C-org and Al, geochemical profiles of Al, Corg, and U clearly show separate distributions after burial. Each component record the synchronous variation of the incoming fluxes, but the position in the sedimentary pile of the recording differs from a... |
| Tipo: Text |
Palavras-chave: Time lag; Sedimentary system; High-resolution record; Modeling; Bioturbation. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33390/31872.pdf |
| |
|
|
| Hanquiez, V; Mulder, T; Lecroart, P; Gonthier, E; Marches, E; Voisset, Michel. |
| In the Gulf of Cadiz, the hydrodynamic process acting on particle transport and deposition is a strong density-driven bottom current caused by the outflow of the saline deep Mediterranean water at the Strait of Gibraltar: the Mediterranean Outflow Water (MOW). New high resolution acoustic data including EM300 multibeam echo-sounder, deep-towed acoustic system SAR and very high resolution seismic, completed by piston cores collected during the CADISAR cruise allow to improve the understanding of the hydrodynamics of the MOW in the eastern part of the Gulf of Cadiz. Interpretation of data corrects the previous model established in this area and allows, for the first time, the accurate characterization of various bedforms and erosive structures along the MOW... |
| Tipo: Text |
Palavras-chave: Instabilities; Sedimentary processes; Acoustic facies; Deep towed SAR; Contourites; Mediterranean Outflow Water MOW; Gulf of Cadiz. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3676.pdf |
| |
|
|
| Deborde, J; Anschutz, P; Auby, Isabelle; Gle, C; Commarieu, M; Maurer, Daniele; Lecroart, P; Abril, G. |
| The hypothesis of nutrient-rich pore-waters seeping at low tide through sediments to channel waters, which drain tidal flats during ebb, was evaluated in the Arcachon lagoon. The back of the bay is affected by freshwater inputs and underground freshwater discharges. The upper part of tidal flat consists of permeable sandy sediments, which are covered by a muddy sediment layer on the lower part. Permeable sediments outcrop in the bed of channel web. Surface water chemistry and early diagenesis processes in sediment were estimated by collecting channel web waters and cores on a tidal flat and in channels at different seasons and time scales. Waters from tidal creeks are under-oxygenated, and enriched in reduced solutes. Muddy sediments showed evidences of... |
| Tipo: Text |
Palavras-chave: Arcachon Bay; Pore waters seeping; Nitrogen; Phosphorus; Organic matter mineralization; Tidal creek water; Tidal pump. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/2008/publication-3927.pdf |
| |
|
|
| Mulder, Thierry; Lecroart, P; Hanquiez, V; Marches, E; Gonthier, E; Guedes, J; Thiebot, E; Jaaidi, B; Kenyon, N; Voisset, Michel; Perez, C; Sayago, M; Fuchey, Y; Bujan, S. |
| Recent multibeam bathymetry and acoustic imagery data provide a new understanding of the morphology of the western part of the Gulf of Cadiz. The gulf is under the influence of a strong current, the Mediterranean Outflow Water (MOW). This current is at the origin of the construction of the giant Contourite Depositional System. Canyons and valleys with erosive flanks are observed. Only the Portimao Canyon is presently connected to the continental shelf. Channels occur on the continental shelf but are presently disconnected from the deeper network of channels and valleys. Slumps are localized in steep slope areas. They are caused by oversteepening and overloading, sometimes probably associated with earthquake activity. Slumps transform sharply into turbidity... |
| Tipo: Text |
Palavras-chave: Contour current; Interaction; Turbidity current; Geomorphology; Gulf of Cadiz. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1718.pdf |
| |
|
|
|
