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Premières observations sur la morphologie et les processus sédimentaires récents de l’Éventail celtique

dc.rights.licenseopenen_US
dc.contributor.authorAUFFRET, Gérard
hal.structure.identifierEnvironnements et Paléoenvironnements OCéaniques [EPOC]
dc.contributor.authorZARAGOSI, Sebastien
IDREF: 189039159
dc.contributor.authorVOISSET, Michel
dc.contributor.authorDROZ, Laurence
dc.contributor.authorLOUBRIEU, Benoı̂t
dc.contributor.authorPELLEAU, Pascal
dc.contributor.authorSAVOYE, Bruno
dc.contributor.authorBOURILLET, Jean-François
dc.contributor.authorBALTZER, Agnès
dc.contributor.authorBOURQUIN, Sylvie
dc.contributor.authorDENNIELOU, Bernard
dc.contributor.authorCOUTELLE, Alain
dc.contributor.authorWEBER, Nicolas
dc.contributor.authorFLOCH, Gilbert
dc.date.accessioned2024-11-15T13:51:51Z
dc.date.available2024-11-15T13:51:51Z
dc.date.issued2000-01-01
dc.identifier.urihttps://www.researchgate.net/publication/240432687_Premieres_observations_sur_la_morphologie_et_les_processus_sedimentaires_recents_de_l'Eventail_celtique
dc.identifier.urioai:researchgate.net:240432687
dc.identifier.urioai:crossref.org:10.1016/s0399-1784(00)00116-x
dc.identifier.urioadoi:http://archimer.ifremer.fr/doc/2000/publication-525.pdf
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/203315
dc.description.abstractEnFirst observations on the morphology and recent sedimentary processes of the Celtic Deep Sea Fan. During the SEDIFAN 1 cruise we surveyed the bathymetry and the acoustic properties of the surface sediment of the Celtic Deep Sea Fan. We also collected Küllenberg cores in order to study recent sedimentary processes. From the bathymetry survey it is relatively easy to recognize the main areas of modern fan. The upper fan included a large sedimentary ridge which constitutes the right levee of the prominent meandering Whittard valley. After its confluence with the Shamrock valley the course of the Whittard valley is abruptly deflected to the south. At a short distance to the south the valley divides into two upper-fan channels, the Celtic channel to the west being the deeper one. This point constitutes the centre of a radiating pattern which is developed on a 150° quadrant and a radius of about 100 km. The acoustic imagery displays contrasted features, related to change in lithology within the first metre beneath the sea bottom and to the sea floor roughness. The Austell ridge exhibits a contrasted pattern of elongated areas with high and low acoustic backscattering levels. This pattern is related to the development of abyssal dunes, the amplitude of which is of metric order. Particularly remarkable is a lobe-shaped low back-scattering area in the western part of the middle fan, also noteworthy are a lineated facies to the west and a braided facies to the east of the fan. The laminated silty-clayey sequences deposited on the Whittard ridge and on the Trevelyan levee were deposited during the deglaciation. We interpret these as turbidity currents overflow deposits from the Whittard valley. At the end of isotopic stage 3 and during stage 2, the English Channel was a large plain flooded by the Channel River. During this period a broad delta developed at 100 m below the present-day depth and a wide spectrum of material was bound to be supplied to the deep sea and contributed particularly to the deposition of the Whittard ridge silty-clayey sequences. The stage 2 deposits are characterized by rhythmic levels enriched in monosulfides. These types of deposits are common in areas affected by fluvial discharges. Excluding the sedimentary ridge and the channel levees the surface deposits sampled with the Küllenberg corer are sandy. These sands are deposited in various contexts on the interfluve between the western and eastern channels and at channel mouths. They were emplaced during high sea level stands as a result of high energy gravity processes. The precise sources of these sands have not yet been identified, however benthic foraminifers from included ooze pebbles have living depths of between 500 and 1 000 m. The gravity processes which eroded this marly ooze may have been triggered on the upper slope. The Celtic shelf is presently a high energy platform where the conjunction of storms and spring tides can lead to enhanced sediment transport from near-shore to the deep sea. The relict or palimpsest deposits of the glacial delta also constitute a large reservoir of sandy material which can also be subject to reworking. © 2000 Ifremer/CNRS/IRD/Éditions scientifiques et médicales Elsevier SASdeep-sea fan / Quaternary / sediment / turbidity / palaeoclimate
dc.language.isoENen_US
dc.sourceresearchgate
dc.sourcecrossref
dc.sourceoadoi_repo
dc.subject.endeep-sea fan
dc.subject.enQuaternary
dc.subject.ensediment
dc.subject.enturbidity
dc.subject.enpalaeoclimate
dc.title.enPremières observations sur la morphologie et les processus sédimentaires récents de l’Éventail celtique
dc.typeArticle de revueen_US
dc.identifier.doi10.1016/s0399-1784(00)00116-xen_US
dc.subject.halSciences de l'environnementen_US
bordeaux.journalOceanologica Actaen_US
bordeaux.page109-116en_US
bordeaux.volume23en_US
bordeaux.hal.laboratoriesEPOC : Environnements et Paléoenvironnements Océaniques et Continentaux - UMR 5805en_US
bordeaux.issue1en_US
bordeaux.institutionUniversité de Bordeauxen_US
bordeaux.institutionCNRSen_US
bordeaux.peerReviewedouien_US
bordeaux.inpressnonen_US
bordeaux.import.sourcedissemin
hal.identifierhal-04785621
hal.version1
hal.date.transferred2024-11-15T13:51:53Z
hal.popularnonen_US
hal.audienceInternationaleen_US
hal.exporttrue
workflow.import.sourcedissemin
dc.rights.ccPas de Licence CCen_US
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Oceanologica%20Acta&rft.date=2000-01-01&rft.volume=23&rft.issue=1&rft.spage=109-116&rft.epage=109-116&rft.au=AUFFRET,%20G%C3%A9rard&ZARAGOSI,%20Sebastien&VOISSET,%20Michel&DROZ,%20Laurence&LOUBRIEU,%20Beno%C4%B1%CC%82t&rft.genre=article


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