Le programme d’EXTension RAisonnée du PLAteau Continental (EXTRAPLAC). Enjeux pour les trois collectivités ultramarines du Pacifique (Nouvelle-Calédonie, Wallis & Futuna, Polynésie française). Auteur(s) : Loubrieu, Benoit Roest, Walter Patriat, Martin Loubersac, Lionel Éditeur(s) : Neidine Editeurs Résumé : This article replaces the French program of legal extension of the continental shelf named EXTRAPLAC, interesting in particular the 3 overseas collectivities of the Pacific (New Caledonia, Wallis and Futuna and French Polynesia)” It considers this program in the context of the Convention of the United Nations on the Maritime law. It clarifies the governance system of this program set up by the authorities of the State. A specific chapter clarifies the constraints to be respected to build up the necessary file in respect of the international Committee requirements so said UNO Commission of the Limits of the Continental shelf. The article considers then scenarios presented by 3 territories and state of progress of the three cases, both regarding the acquisition of the useful data and the planning of adequate oceanographic campaigns and structuring the administrative files in front of the UNO in conjunction with the border countries. The article ends finally on the potential extensions, the exploitation rights of mineral and living resources as the obligations which it supposes Cet article replace le programme français d’extension juridique du plateau continental nommé EXTRAPLAC, intéressant notamment les 3 collectivités d’Outre-Mer du Pacifique (Nouvelle-Calédonie, Wallis et Futuna et Polynésie française) dans le contexte de la Convention des Nations Unies sur le Droit de la Mer. Il explicite le système de gouvernance de ce programme mis en place par les autorités de l’Etat. Un chapitre spécifique explicite les contraintes à respecter pour construire un dossier de demande présentable devant la Commission internationale spécialisée de l’ONU dite Commission des Limites du Plateau Continental. L’article considère ensuite les cas de figures présentés par les 3 territoires et l’état d’avancement des dossiers tant en matière d’acquisition des données utiles et de planification de campagnes océanographiques adéquates que de structuration et de dépôt administratif devant l’ONU en conjonction avec les pays frontaliers. L’article conclue enfin sur les extensions potentielles, les droits d’exploitation de ressources qui peuvent en être tirés comme les obligations que cela suppose. Taï Kona (2269-7535) (Neidine Editeurs), 2014 , N. 11 , P. 18 - 26 Droits : info:eu-repo/semantics/openAccess http://archimer.ifremer.fr/doc/00217/32820/31254.pdf http://archimer.ifremer.fr/doc/00217/32820/ | Partager |
Moyens mis en oeuvre pour la cartographie du plateau continental - Guide général Auteur(s) : Rollet, Claire Breton, Cecile Loubrieu, Benoit Satra Le Bris, Catherine Résumé : Sur le plateau continental, du littoral jusqu’aux fonds atteignant une profondeur de plus 200 m, une multitude de données océanographiques est recueillie à partir d’une grande diversité de moyens. Ces moyens, souvent mis en œuvre de façon complémentaire, font appel à des technologies et à des expertises variées. Ce document présente les différentes technologies mise en œuvre pour la cartographie du plateau continental. Il introduit une série de guides, chacun étant dédié spécifiquement à une technique de la cartographie numérique. Droits : 2010 Ifremer http://archimer.ifremer.fr/doc/00071/18237/15801.pdf http://archimer.ifremer.fr/doc/00071/18237/ | Partager |
Mass-transport deposits and fluid venting in a transform margin setting, the eastern Demerara Plateau (French Guiana) Auteur(s) : Pattier, France Loncke, L. Gaullier, V. Basile, C. Maillard, Alexandre Imbert, Patrice Roest, Walter Vendeville, B. C. Éditeur(s) : Elsevier Sci Ltd Résumé : The eastern Demerara Plateau offshore French Guiana was surveyed in 2003 during the GUYAPLAC cruise (multibeam bathymetry and acoustic imagery, 6-channel seismic reflection and 3.5 kHz echo-sounding). The data show the "post-transform" Cenozoic that the series located on the outer part of the plateau (below c. 2000 m) contain at least twelve stacked mass transport deposits (MTDs) that have recorded a history of large-scale slope failure, as well as two main normal fault sets that provide possible pathways for upward fluid migration through the series, reaching at high as the uppermost MTDs. Seabed data show that the area above the failures is characterized by circular-to-elongate (slope-parallel) depressions interpreted as fluid seeps (pockmarks), some of them have been modified by along slope currents. We suggest that the development of the MTDs to results from the combinaiton of the presence of fluid overpressure at depth the geometry of the margin's deep structure, in particular the existence of a 'free borderlateral border' on the outermost plateau. Our results also emphasise the role of stratigraphic decollements within the Cenozoic series. Marine And Petroleum Geology (0264-8172) (Elsevier Sci Ltd), 2013-09 , Vol. 46 , P. 287-303 Droits : 2013 Elsevier Ltd. All rights reserved. http://archimer.ifremer.fr/doc/00157/26850/25316.pdf DOI:10.1016/j.marpetgeo.2013.06.010 http://archimer.ifremer.fr/doc/00157/26850/ | Partager |
Premières observations sur la morphologie et les processus sédimentaires récents de l'Éventail celtique Auteur(s) : Auffret, Gérard-andré Zaragosi, S Voisset, Michel Droz, Laurence Loubrieu, Benoit Pelleau, Pascal Savoye, R Bourillet, Jean-francois Éditeur(s) : Elsevier Résumé : 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 Kullenberg 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 degrees 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 Kullenberg 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 marry 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 call 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. Le programme Enam 2 (European North Atlantic Margin) concerne l'étude des processus sédimentaires quaternaires du Spitzberg au golfe de Gascogne. Dans le cadre de ce programme, la reconnaissance de l'Éventail profond celtique était l'objectif de la campagne Sedifan 1 au cours de laquelle nous avons établi la morphologie de l'éventail et obtenu une image acoustique des fonds sédimentaires. La morphologie permet de mettre en évidence une organisation en éventail. On note aussi le développement remarquable d'une ride sédimentaire au niveau de l'éventail supérieur. Les sédiments prélevés révèlent la présence de dépôts sableux, témoins d'une activité récente qui pourrait être liée à l'importance de l'hydrodynamisme sur les Grands Bancs de la plate-forme celtique. Oceanologica Acta (0399-1784) (Elsevier), 2000 , Vol. 23 , N. 1 , P. 109-116 Droits : 2000 Ifremer/CNRS/IRD/Editions scientifiques et medicales Elsevier SAS http://archimer.ifremer.fr/doc/2000/publication-525.pdf DOI:10.1016/S0399-1784(00)00116-X http://archimer.ifremer.fr/doc/00000/525/ | Partager Voir aussi Paléoclimat Turbidité Sédiment Quaternaire Eventail profond Palaeoclimate Turbidity Sediment Quaternary Deep sea fan Télécharger |