Éditeur(s) : University of Miami
Résumé : This paper describes the fishing activity in Martinique, French West Indies. It draws up the balance sheet of acquirements about marine resources of the island. The difficulties of fisheries management are discussed with reference to biologists and economists works in the last ten years. We also show how management efforts to decrease fishing pressure on reef resources has induced the implantation of a new technology: the Fish Aggregating Deviee. The differing histories of development of FADs in the French West Indies are compared. The positive results from the introduction of the FADs and the estimated risks due to the transferance of fishing pressure on the continental shelf is presented. The use of FADs to enhance the exploitation of marine resources is a concept that justifies.a cooperative plan throughout the Caribbean region
A partir d'une présentation synthétique de l'activité de pêche en Martinique, cette note dresse le bilan des connaissances actuelles sur l'état des ressources halieutiques de l'île. Les difficultés de la gestion des pêches sont discutées en référence aux travaux réalisés par les halieutes et les économistes des pêches au cours des dix dernières années. On montre comment un objectif de gestion, l'allégement de la pression de pêche sur les ressources démersales, a pu conduire à l'implantation d'une nouvelle technologie: le dispositif de concentration de poissons. Les différents contextes de développement des DCP observés dans les deux départements français des Antilles sont comparés. Les retombées positives de l'introduction des dispositifs sont évaluées mais le risque d'aboutir à un report d'une partie de la puissance de pêche sur le plateau est également évoqué. L'influence du DCP sur l'exploitation des ressources halieutiques constitue un argument supplémentaire pour intensifier la coopération caribéenne sur ce thème
Proceedings - Gulf and Caribbean Fisheries Institute, University of Miami (0072-9019) (University of Miami), 1998 , Vol. 50 , P. 249-261

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00113/22409/20106.pdf
http://archimer.ifremer.fr/doc/00113/22409/

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Since the beginning of 1980, the Martinique fishermen have suffered a deep crisis. The traditional ways of fishing, based on benthic fish exploitation, have seen the decreasing of their profitability due to the over-fishing of the narrow continental shelf offering few resources. The pelagic fishery had become the professional main source of income. This fishery equally encounter difficulties: denied rights of access in the EEZ of Caribbean islands, expensive costs of exploitation. The disposal of FADs offers new ways to the Martinique fishermen. In 1999, it was decided the disposal of a onetworko of 30 permanent FADs around Martinique. The mooring of these FADs must be followed by legal and economic adapted measures to reach the desired aim: the development of local fishery economy through a sustainable fishing practice. Therefore, the French authorities have decided to make the regional fishermen committee responsible for the management of FADs.This committee is the only one to be entitled to moor and to deliver licences to FADs. This committee, gathering all the fishing industry representatives, has regarding the french law the right of mooring and delivering licences to the FADs access, collecting fishery statistics. These data should fund research to improve the management of the fishery, care and replace FADs. This programas realisation, as well as durability, need adequate financial planning. It has been included in the European commission financing program. This plans success will ensure the increase of the fishermen income, maintain and develop employment.Original Abstract: Apres une periode d'experimentation lancee localement au debut des annees quatre-vingt, les premiers resultats ont ete suffisamment probants pour conduire les professionnels a souhaiter l'implantation de dispositifs de concentration de poissons (dcp) en Martinique ou a les implanter eux-memes pour la capture des dorades coryphenes, des thons noirs, de l'albacore ou du listao. Le colloque international sur la peche thoniere et les dispositifs de concentration de poissons organise du 15 au 19 octobre 1999 en Martinique donne l'occasion de revenir sur le contexte, l'interet et les modalites de developpement de la technique des dcp en Martinique.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15305/12639.pdf
http://archimer.ifremer.fr/doc/00042/15305/

Éditeur(s) : HAL CCSD Elsevier
Résumé : The current interpretation of the Messinian Salinity Crisis (MSC) involves the deposition of the so-called “peripheral or marginal” evaporites in onshore basins, as well as the erosion of the margins and the formation of thick evaporites in the deep parts of the basins. The present study focuses on intermediate depth basins, i.e. located between the onshore outcrops and the deep basins. Indeed, the Balearic Promontory shows small stepped basins filled with MSC deposits between its western extremity on the Alicante shelf and its eastern end around the Menorca block. New and already available seismic reflection profiles and onshore data allow us to investigate the nature and geometrical relationships of these deposits in the area between the islands of Ibiza and Mallorca.Our observations suggest the existence of three MSC-related units in this area. The lowermost transparent seismic unit can be interpreted as a 100 to 200-m-thick salt layer deposited in the deepest part of the Central Mallorca Depression. These evaporites pass laterally and upward into a thin-bedded seismic unit, which could be lithologically equivalent to the Upper Evaporites of the deep basins. All around the borders of the Central Mallorca Depression, this bedded seismic unit onlaps a Slope Unit which shows bedded to chaotic and rafted facies. The Messinian continental shelf is eroded and incised by a valley extending from the Palma onshore area to the Mallorca downslope domain.Our results suggest the presence offshore of at least two generations of diachronous MSC deposits. The observation of salt on a continental high and the widespread MSC deposits on the margins of the Central Mallorca Depression call into question the location of halite preferentially in the deep abyssal basins and the significance of the deep basin MSC units that onlap onto the Margin Erosional Surface (MES), as observed all around the passive margins of the Northwest-Mediterranean Basin. The dual terminology used for peripheral/deep MSC evaporites cannot be applied to any of the MSC units found in the study area.
ISSN: 0025-3227

hal-01115656
https://hal.archives-ouvertes.fr/hal-01115656
DOI : 10.1016/j.margeo.2014.10.001

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The interpretation of high-resolution 2D marine seismic profiles together with the analysis of sea-bottom cores allowed a stratigraphic and structural framework of the Provence continental shelf to be proposed. The integration of onshore and offshore stratigraphy, structure and geomorphology provided new insights into Messinian paleotopography and paleohydrography. A geological map of the offshore Provence continental shelf, isobath map of the base Plio-Quaternary surface are presented for the first time in this area. The base Plio-Quaternary surface is a polyphased unconformity that is composed of deep canyons developed by fluvial erosion during the Messinian event, and wave-cut surfaces formed during post-Messinian transgressions. The study evidenced a deep, E-W-trending canyon (Bandol canyon) connected to the head of the Cassidaigne canyon, and filled with up to 600 m-thick Plio-Quaternary deposits. The development of canyons on the Provence margin during the Messinian event was dominantly controlled by the lithology and structure of pre-Messinian formations. A map of the Messinian paleo-drainage network is proposed to explain the presence of deep canyons in the Eastern area and the lack of incision in the Western area. An underground karst drainage scheme is proposed, linked with the current submarine Port-Miou spring.
ISSN: 0264-8172

insu-01009592
https://hal-insu.archives-ouvertes.fr/insu-01009592
https://hal-insu.archives-ouvertes.fr/insu-01009592/document
https://hal-insu.archives-ouvertes.fr/insu-01009592/file/Mar-Pet-Tassy.pdf
DOI : 10.1016/j.marpetgeo.2014.05.001

Éditeur(s) : HAL CCSD
Résumé : 38 pages
Rapport
The Chicxulub impact crater, México, is unique. It is the only known terrestrial impact structure that has been directly linked to a mass extinction event and the only terrestrial impact with a global ejecta layer. Of the three largest impact structures on Earth, Chicxulub is the best preserved. Chicxulub is also the only known terrestrial impact structure with an intact, unequivocal topographic peak ring. Chicxulub’s role in the Cretaceous/Paleogene (K-Pg) mass extinction and its exceptional state of preservation make it an important natural laboratory for the study of both large impact crater formation on Earth and other planets and the effects of large impacts on the Earth’s environment and ecology. Our understanding of the impact process is far from complete, and despite more than 30 years of intense debate, we are still striving to answer the question as to why this impact was so catastrophic.During International Ocean Discovery Program (IODP) Expedition 364, Paleogene sediments and lithologies that make up the Chicxulub peak ring were cored to investigate (1) the nature and formational mechanism of peak rings, (2) how rocks are weakened during large impacts, (3) the nature and extent of post-impact hydrothermal circulation, (4) the deep biosphere and habitability of the peak ring, and (5) the recovery of life in a sterile zone. Other key targets included sampling the transition through a rare midlatitude section that might include Eocene and Paleocene hyperthermals and/or the Paleocene/Eocene Thermal Maximum (PETM); the composition and character of the impact breccias, melt rocks, and peak-ring rocks; the sedimentology and stratigraphy of the Paleocene–Eocene Chicxulub impact basin infill; the chronology of the peak-ring rocks; and any observations from the core that may help us constrain the volume of dust and climatically active gases released into the stratosphere by this impact. Petrophysical property measurements on the core and wireline logs acquired during Expedition 364 will be used to calibrate geophysical models, including seismic reflection and potential field data, and the integration of all the data will calibrate impact crater models for crater formation and environmental effects. The proposed drilling directly contributes to IODP Science Plan goals:Climate and Ocean Change: How resilient is the ocean to chemical perturbations? The Chicxulub impact represents an external forcing event that caused a 75% level mass extinction. The impact basin may also record key hyperthermals within the Paleogene.Biosphere Frontiers: What are the origin, composition, and global significance of subseafloor communities? What are the limits of life in the subseafloor? How sensitive are ecosystems and biodiversity to environmental change? Impact craters can create habitats for subsurface life, and Chicxulub may provide information on potential habitats for life, including extremophiles, on the early Earth and other planetary bodies. Paleontological and geochemical studies at ground zero will document how large impacts affect ecosystems and effects on biodiversity.Earth Connections/Earth in Motion: What are the composition, structure and dynamics of Earth’s upper mantle? What mechanisms control the occurrence of destructive earthquakes, landslides, and tsunami? Mantle uplift in response to impacts provides insight into dynamics that differ between Earth and other rocky planets. Impacts generate earthquakes, landslides, and tsunami, and scales that generally exceed plate tectonic processes yield insight into effects, the geologic record, and potential hazards.IODP Expedition 364 was a Mission Specific Platform expedition to obtain subseabed samples and downhole logging measurements from the sedimentary cover sequence and peak ring of the Chicxulub impact crater. A single borehole was drilled into the Chicxulub impact crater on the Yucatán continental shelf, recovering core from 505.7 to 1334.73 m below seafloor with ~99% core recovery and acquiring downhole logs for the entire depth.
International Ocean Discovery Program

hal-01639520
https://hal.archives-ouvertes.fr/hal-01639520
DOI : 10.14379/iodp.pr.364.2017

Éditeur(s) : Elsevier
Résumé : A study of organic carbon mineralization from the Congo continental shelf to the abyssal plain through the Congo submarine channel and Angola Margin was undertaken using in situ measurements of sediment oxygen demand as a tracer of benthic carbon recycling. Two measurement techniques were coupled on a single autonomous platform: in situ benthic chambers and microelectrodes, which provided total and diffusive oxygen uptake as well as oxygen microdistributions in porewaters. In addition, sediment trap fluxes, sediment composition (Org-C, Tot-N, CaCO3, porosity) and radionuclide profiles provided measurements of, respectively input fluxes and burial rate of organic and inorganic compounds. The in situ results show that the oxygen consumption on this margin close to the Congo River is high with values of total oxygen uptake (TOU) of 4 +/- 0.6, 3.6 +/- 0.5 mmol m(-2) d(-1) at 1300 and 3100m depth, respectively, and between 1.9 +/- 0.3 and 2.4 +/- 0.2 mmol m(-2) d(-1) at 4000 m depth. Diffusive oxygen uptakes (DOU) were 2.8 +/- 1.1, 2.3 +/- 0.8, 0.8 +/- 0.3 and 1.2 +/- 0.1 mmol m(-2) d(-1), respectively at the same depths. The magnitude of the oxygen demands on the slope is correlated with water depth but is not correlated with the proximity of the submarine channel-levee system, which indicates that cross-slope transport processes are active over the entire margin. Comparison of the vertical flux of organic carbon with its mineralization and burial reveal that this lateral input is very important since the sum of recycling and burial in the sediments is 5-8 times larger than the vertical flux recorded in traps. Transfer of material from the Congo River occurs through turbidity currents channelled in the Congo valley, which are subsequently deposited in the Lobe zone in the Congo fan below 4800 m. Ship board measurements of oxygen profiles indicate large mineralization rates of organic carbon in this zone, which agrees with the high organic carbon content (3%) and the large sedimentation rate (19 mm y(-1)) found on this site. The Lobe region could receive as high as 19 mol C m(-2) y(-1), 1/3 being mineralized and 2/3 being buried and could constitute the largest depocenter of organic carbon in the South Atlantic.
Deep Sea Research Part II: Topical Studies in Oceanography (0967-0645) (Elsevier), 2009-11 , Vol. 56 , N. 23 , P. 2223-2238

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-7316.pdf
DOI:10.1016/j.dsr2.2009.04.005
http://archimer.ifremer.fr/doc/00000/7316/

Éditeur(s) : Geological Society of America
Résumé : A seismic-refraction study of the sedimentary structure of the South West African continental shelf was carried out between lat 17°S and 24°S using expendable sonobuoys. Striking differences exist both in the topography and sedimentary structure between the shelf north and south of the Walvis Ridge. South of the ridge, as far as lat 23°S, the shelf consists of a prograded series, whereas north of the ridge, at least as far as lat 17°S, east-trending canyons cut the shelf sedimentary cover. The steep northem scarp of Walvis Ridge can be traced eastward under the sediment of the continental margin. The southern flank of the ridge is buried under a thicker sedimentary cover and could only be traced eastward to long. 10°E on seismic-reflection records. This flank probably parallels the northern scarp under the continental margin. Two-dimensional structural models, built with the help of seismic-retlection and seismic-refraction results and based on the hypothesis of local isostatic equilibrium, account for the obsewed gravity profiles. A compensating root consists of light material (density 2.95 g/cm3) and reaches a depth of about 25 km. Gravity results also suggest that the Walvis Ridge does not constitute a superimposed load on the lithosphere; rather, the ridge and its underlying compensating mass were created at approximately the same time as the adjacent ocean basins. The creation of the two aseismic ridges of the South Atlantic - the Rio Grande Rise and Walvis Ridge - by a mantle hot spot and plume is accepted; this theory seems to explain most of the peculiar features of the Walvis Ridge. However, it is probable that the surface expression of the mantle hot spot was controlled by the presence of weak zones in the lithosphere such as transform faults. [NOT CONTROLLED OCR]
Geological Society of America Bulletin (Geological Society of America), 1975 , Vol. 86 , P. 1713-1724

Droits : Geological Society of America
http://archimer.ifremer.fr/doc/1975/publication-4978.pdf
http://archimer.ifremer.fr/doc/00000/4978/

Résumé : The populations of fishes dwelling near the sea bed (demersal species) on the continental shelf are usually the object of intense commercial exploitation. The Bay of Biscay shelf is no exception. Hence, populations suffer from this exploitation. Moreover, the general role played by hydro-climatic variations in the regulation of the abundance of demersal fish populations (population dynamics) is traditionally admitted. In the Bay of Biscay, a warming of the surface water has been observed over the three last decades (Koutsikopoulos et al., 1998). Climate change therefore has potential consequences on fish communities. Thus, the structure and dynamics of fish populations on the continental shelf of the Bay of Biscay are susceptible to suffer both from the effects of a human activity (fishing) and of climate change (warming). Fisheries should therefore suffer more or less from these changes depending on their adaptation capacity.
Les peuplements de poissons vivant à proximité du fond (espèces démersales) sur le plateau continental font généralement l'objet d'une exploitation commerciale intense. Le plateau du Golfe de Gascogne n'échappe pas à cette règle. Les populations y subissent donc les effets de l'exploitation. Par ailleurs, le rôle général des variations hydro-climatiques dans la régulation de l'abondance des populations démersales de poissons (la dynamique des populations) est classiquement admis. Dans le Golfe de Gascogne, un réchauffement des eaux de surface au cours des trois dernières décennies est observé (Koutsikopoulos et al., 1998). Le changement climatique a donc des conséquences potentielles sur la communauté de poissons. Ainsi, la structure et la dynamique du peuplement de poissons du plateau continental du Golfe de Gascogne sont susceptibles de répondre à la fois aux effets d'une activité humaine (la pêche) et du changement climatique (réchauffement). Les pêcheries devraient donc subir ces changements selon leur capacité d'adaptation.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/rapport-6347.pdf
http://archimer.ifremer.fr/doc/00000/6347/

Éditeur(s) : ISTPM
Résumé : From a sedimentological point of view, the continental shelf of the French Guyana can be divided in three parts, parallel to the littoral: (1) the coastal zone where a very fluid mud is found; (2) a large band of sands which covers the rest of the continental shelf; (3) the zone of pelagic muds which corresponds to the lower part of the continental slope. The passage between the sands of the shelf and the littoral or pelagic muds is obtained by the intermediary of the muddy sands.
Revue des Travaux de l'Institut des Pêches Maritimes (0035-2276) (ISTPM), 1977-12 , Vol. 41 , N. 4 , P. 389-402

Droits : Ifremer
http://archimer.ifremer.fr/doc/1977/publication-1991.pdf
http://archimer.ifremer.fr/doc/00000/1991/

Éditeur(s) : Société franco-japonaise d'océanographie
Résumé : French fishermen have been fishing porbeagle shark Lamna nasus on the edges of the continental shelf, from the Bay of Biscay to the south of Ireland. Incidentally, until the past few years, when, during summer, bluefin tunas Thunnus thynnus, albacores Thunnus alalunga and sworfishes Xiphias gladius were caught on the same line. Since 1970, some fishermen have started focusing on swordfish. The authors describe the technique and gear used for this fishery. A fishery that could largely develop in the years to come.
Les pêcheurs artisans français pêchent depuis une vingtaine d'années le requin sonneur (ou taupe) Lamna nasus sur les accores du plateau continental du Colfe de Gascogne jusqu'au Sud de l'Irlande. Incidemment jusqu'à ces dernières annees, durant l'été, des thons rouges Thunnus thynnus, des germons Thunnus alalunga et des espadons Xiphias gladius étaient capturés A l'aide de cette même palangre. Depuis 1970, quelques pêcheurs commencent à développer un effort de pêche particulier pour la capture de l'espadon. Les auteurs décrivent la technique et les engins de cette pêche qui peut se développer beaucoup plus largement dans les années à venir. [OCR NON CONTRÔLE]
Bulletin de la Société franco-japonaise d'océanographie (Société franco-japonaise d'océanographie), 1972-11 , Vol. 10 , N. 4 , P. 174-177

Droits : Société franco-japonaise d'océanographie
http://archimer.ifremer.fr/doc/1972/publication-5140.pdf
http://archimer.ifremer.fr/doc/00000/5140/

Éditeur(s) : Elsevier
Résumé : The Danube Canyon is a large shelf-indenting canyon that has developed seaward of the late Pleistocene paleo-Danube valley. Mechanisms of canyon evolution and factors that controlled it are revealed by analyzing the morphology and the sedimentary structure of the canyon, as well as the main features of the continental margin around the canyon. This is based on investigation by swath bathymetry in the canyon area combined with different types of seismic data. The canyon is a major erosional trough with a flat bottom cut by an entrenched axial thalweg. The thalweg path varies from highly meandering to fairly straight in relation to the local gradient. Segments of the canyon are characterized by specific morphology, orientation and gradient along the axial thalweg. We interpret these segments in terms of canyon maturity. The sedimentary structure of the canyon documents an older phase of erosion followed by partial infilling, and thus attests for repeated cycles of canyon development. Canyon morphology is interpreted as a result of erosive sediment flows along the entrenched axial thalweg that caused downcutting into the canyon bottom and instability of the canyon walls, and hence enlargement of the canyon and expansion by headward erosion. During the last lowstand level of the Black Sea the canyon was located in an area of high sediment supply close to the paleo-Danube River mouths. This is indicated by buried fluvial channels on the shelf and by a wave-cut terrace associated with a water level situated about - 90 m below the present level. We infer that erosive flows in the canyon resulted from hyperpycnal currents at the river mouths, probably favored by the low salinity environment that characterized the Black Sea during lowstand times. Other mechanisms could have contributed to trigger sediment failure along the canyon, such as instability related to the presence of shallow gas, or the effect of a deep fault.
Marine Geology (0025-3227) (Elsevier), 2004-05 , Vol. 206 , N. 1-4 , P. 249-265

Droits : 2004 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/2004/publication-476.pdf
DOI:10.1016/j.margeo.2004.03.003
http://archimer.ifremer.fr/doc/00000/476/

Éditeur(s) : Elsevier
Résumé : In biological modelling of the coastal phytoplankton dynamics, the light attenuation coefficient is often expressed as a function of the concentrations of chlorophyll and mineral suspended particulate matter (SPM). In order to estimate the relationship between these parameters over the continental shelf of the northern Bay of Biscay, a set of in situ data has been gathered for the period 1998-2003 when SeaWiFS imagery is available. These data comprise surface measurements of the concentrations of total SPM, chlorophyll, and irradiance profiles from which is derived the attenuation coefficient of the photosynthetically available radiation, K-PAR. The performance of the IFREMER look-up table used to retrieve the chlorophyll concentration from the SeaWiFS radiance is evaluated on this new set of data. The quality of the estimated chlorophyll concentration is assessed from a comparison of the variograms of the in situ and satellite-derived chlorophyll concentrations. Once the chlorophyll concentration is determined, the non living SPM, which is defined as the SPM not related to the dead or alive endogenous phytoplankton, is estimated from the radiance at 555 nm by inverting a semi-analytic model. This method provides realistic estimations of concentrations of chlorophyll and SPM over the continental shelf all over the year. Finally, a relationship, based on non living SPM and chlorophyll, is proposed to estimate K-PAR on the continental shelf of the Bay of Biscay. The same formula is applied to non living SPM and chlorophyll concentrations, observed in situ or derived from SeaWiFS radiance.
Remote Sensing of Environment (0034-4257) (Elsevier), 2005-03 , Vol. 95 , N. 1 , P. 29-46

Droits : 2004 Elsevier Inc. All rights reserved
http://archimer.ifremer.fr/doc/2005/publication-1172.pdf
DOI:10.1016/j.rse.2004.11.007
http://archimer.ifremer.fr/doc/00000/1172/

Éditeur(s) : Institut de Ciències del Mar de Barcelona, CSIC
Résumé : Acoustic and core data have recently been collected on the shelf break and the upper part of the slope of the south Aquitaine continental margin. They reveal the major role played by mass-flow gravity processes in deposit erosion and redistribution, modelling of the sea-bed, and transfer of sediment toward the deep-sea. The study region is bounded in the south by the Capbreton canyon. The northern area, which shows a smooth morphology, is characterised by small-scale deformations due to sediment creep or low-amplitude slide processes. The deformations are associated with mini listric-like faults that bound packets of sediments in which the deposit geometry is typical of constructional sediment waves. These sediment waves result from the interaction of depositional and gravity deformation processes. In the southern area, closer to the canyon, wave-like structures are still present but mostly of smaller size. They only result from gravity deformation processes without any evidence of constructional processes. In the vicinity of the Capbreton canyon, the shelf break and upper slope have a much more uneven morphology with sedimentary reliefs, escarpments and depressions directed toward the canyon thalweg. The depressions look like slide scars, and could be the result of regressive slides initiated at the top of the canyon flank. The age of the sliding event responsible for the formation of the depression observed today could be middle to upper Quaternary. Since their formation, these depressions act as conduits that channel the transfer of shelf sediment into the canyon, as demonstrated by the occurrence of a meandering channel on the sea-floor of one depression.
Scientia Marina (0214-8358) (Institut de Ciències del Mar de Barcelona, CSIC), 2006-06 , Vol. 70 , N. 1 , P. 89-100

Droits : 2006 Institut de Ciències del Mar de Barcelona
http://archimer.ifremer.fr/doc/2006/publication-3960.pdf
http://archimer.ifremer.fr/doc/00000/3960/

Éditeur(s) : Observatoire Océanologique de Banyuls sur mer
Résumé : A new species of a polychaetous annelid belonging to the genus Polydora is described. It was collected on the continental shelf of the western Mediterranean sea. Some morphological features are not consistent with the generic diagnosis. [NOT CONTROLLED OCR]
Vie et Milieu (Observatoire Océanologique de Banyuls sur mer), 1974 , Vol. 24 , N. 3A , P. 479-486

Droits : Observatoire Océanologique de Banyuls sur mer
http://archimer.ifremer.fr/doc/1974/publication-4981.pdf
http://archimer.ifremer.fr/doc/00000/4981/

Éditeur(s) : Gauthier-Villars
Résumé : The continental shelf is very narrow and steep to the north, and broader to the South. This shelf is structuraly influenced by the Andes. This area is mainly covered with terrigenous deposits, i.e. muds and sands which are recent on the internal shelf and relict on the external shelf. The sediments, supplied by rivers, reflect the intense erosion of the Andean backland. This erosion can only be reduced in situ by the vegetation cover. Clays are the main component of the fine fraction reaching the sea. Three different clay assemblages are observed: 1) an Andean (illite-chlorite) assemblage, reflecting the proximity of the cordillera; 2) a mid-American assemblage (smectite), which supplies the North Pacific Margin through the Choco counter-current; 3) an Equatorial assemblage (smectites) which is brought to the South by the Colombian current.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1995 , Vol. 18 , N. 1 , P. 1-18

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00097/20862/18480.pdf
http://archimer.ifremer.fr/doc/00097/20862/

Éditeur(s) : HAL CCSD Blackwell Publishing
Résumé : International audience
In the Causses platform (south-east France), Late Hettangian to Sinemurian deposits were interpreted previously as shallow-water carbonate ramp deposits. A new look at these deposits has shown a fault-controlled mosaic carbonate platform that is different from the carbonate ramp models. Within the platform mosaic, 15 lithofacies have been recognized, which are organized in four facies associations, including peritidal, restricted shallow sub-tidal, sand dunes and sub-tidal shelf facies associations. The rapid lateral and vertical facies changes, and the lack of consistent landward or seaward direction indicated by the pattern of facies changes, question the existence of a shoreline suggested by the traditional models for this region. Instead, the facies organization and cycle stacking pattern suggest deposition in a mosaic of intertidal islands between which sub-tidal restricted or open conditions could coexist in very close proximity. Such a platform mosaic would have been defined by tectonic activities along normal faults which segmented the shallow-water Causses platform. The facies and facies associations are arranged into metre-scale, peritidal and sub-tidal cycles that are also variable. Certain cycles show the same stacking pattern in all the sections and seem to be traceable over tens of kilometres. On the contrary, other cycles cannot be correlated; they are present only in specific sections and have a maximum lateral extension of 1 or 2 km. These metre-scale cycles stack to form four medium-scale cycles bounded by surfaces that display sub-aerial exposure features. Medium-scale cycles stack into two larger-scale cycles (tens of metres thick) and are bounded by well-defined karstic surfaces. Based on their lateral continuity and their stacking pattern, the metre-scale cycles are controlled probably by high frequency eustatic variations overprinting the topographic irregularities formed by differential subsidence of fault-bounded blocks. Episodic fault activities may reorganize the topography so that, even if eustatic changes may still be the major control of cycles, the expression and number of cycles could be different. Cycles of medium and large-scale are interpreted as being allogenic, controlled by changes in eustasy and/or subsidence rates as evidenced by their lateral continuity and the correlations of the large-scale cycles with third-order depositional sequences.
ISSN: 1469-3496

hal-00411940
https://hal.archives-ouvertes.fr/hal-00411940
DOI : 10.1111/j.1365-3091.2007.00896.x

Éditeur(s) : John Wiley & Sons
Résumé : Based on all available seismic refraction data, the seismic structure of the Western Approaches to the English Channel and the South Armorican continental shelf has been established. The correlation of seismic velocities showed a three-fold structure, related to geological layers as follows: 1. High-velocity, deep sequence (4.4-6.6km/sec): metamorphic basement and Lower to Middle Palaeozoic. 2. Intermediate sequence (3.6-4.3km/sec): Permo-Triassic (and Jurassic?) and possibly also Lower Cretaceous on the margin of the Western Approaches. 3. Upper sequence (1.9-3.6km/sec): Cretaceous and Cenozoic sediments. An acoustic unconformity appears to be present between the Upper sequence and the High velocity and Intermediate sequences. Different geomorphology characterizes these layers: the Palaeozoic is tectonized and generally follows the Hercynian structural trends; mainly Permo-Triassic sediments fill the depressions of the Palaeozoic floor, but only in the Western Approaches; eastwards-transgressive Cretaceous and Cenozoic sediments cover discordantly the preceding layers. [NOT CONTROLLED OCR]
Petroleum and the continental shelf of North-west Europe (John Wiley & Sons), 1975 , P. 29-43

Droits : John Wiley & Sons
http://archimer.ifremer.fr/doc/1975/publication-5465.pdf
http://archimer.ifremer.fr/doc/00000/5465/

Éditeur(s) : Elsevier
Résumé : The present work is based on a set of bottom trawl surveys performed in the Gulf of Lions between 1983 and 1992. A new method which couples the STATIS multitable approach with the logic of correspondence analysis (CoA) is proposed to study the stability of spatial organization of demersal assemblages in terms of species composition. This CoA version of STATIS has provided a clear representation of the stable part of the spatial structure of the assemblages. In addition, it gave an insight into the interannual variations of the distribution of each population around the reference structure. Our results showed that the demersal assemblages of the Gulf of Lions exhibited strong spatial structuring, mainly orientated along a bathymetric gradient. This gradient is structured around three major regions: the coast, the continental shelf and the continental slope. Despite sampling variations that occurred during the course of the study, the analysis showed a high degree of reproducibility for this spatial pattern. With the exception of Mullus surmuletus, the species considered in this investigation exhibit limited variations in their spatial distribution. Finally, in the absence of log-books covering the activities of commercial fishing vessels, these findings constitute a base of reference for the analysis of the dynamics of fishing fleets exploiting the demersal resources of the Gulf of Lions.
Ce travail porte sur une série de campagnes de chalutage de fond réalisé dans le golfe du Lion entre 1983 et 1992. Une nouvelle méthode fondée sur le couplage de la technique multitableaux STATIS et de l'analyse factorielle des correspondances (AFC) est proposée afin d'étudier l'organisation spatio-temporelle des assemblages démersaux, poissons et quelques céphalopodes, en terme de composition spécifique. Cette version AFC de STATIS a fourni une représentation claire de la part stable de l'organisation spatiale des assemblages. De plus, elle nous a permis d'appréhender les variations interannuelles de la distribution de chaque population autour de la structure de référence. Nos résultats montrent que les assemblages démersaux du golfe du Lion présentent une forte structuration spatiale, principalement orientée selon un gradient bathymétrique. Ce dernier est structuré en trois grandes régions: la côte, le plateau continental et le talus continental. En dépit des variations d'échantillonnage survenues au cours de la période d'étude, l'analyse a mis en évidence une forte reproductibilité de ce schéma d'organisation. A l'exception de Mullus surmuletus, les espèces considérées dans ce travail présentent des variations limitées de leur distribution spatiale. Enfin, en l'absence de livres de bord sur l'activité des navires professionnels, ces résultats constituent une base de référence pour l'analyse de la dynamique des flottilles exploitant les ressources démersales dans le golfe du Lion.
Aquatic Living Resources (Elsevier), 1998-03 , Vol. 11 , N. 2 , P. 75-85

Droits : 1998 Published by Elsevier SAS
http://archimer.ifremer.fr/doc/1998/publication-875.pdf
DOI:10.1016/S0990-7440(98)80063-6
http://archimer.ifremer.fr/doc/00000/875/

Éditeur(s) : Cnexo
Résumé : Article 246 of the international agreement on marine legislation project deals with the practical conditions of scientific research in the exclusive economic area and on the continental shelf. We feel heavily concerned by this article and the first consequences of this new legislation begin to be felt in a very unpleasant way. In a large portion of seas and oceans, corresponding to the exclusive economic areas, research is subjected to the authorisation granted "in normal circumstances" by coastal states if it is conducted "exclusively for a peaceful purpose and in the aim to increase the scientific knowledge on marine environment in the interest of the whole of humanity."
L'article 246 du projet de convention internationale sur le droit de la mer traite des conditions d'exercice de la Recherche Scientifique dans la zone économique exclusive et sur le plateau continental. Il nous concerne au premier chef et les premières conséquences de ce droit émergeant commencent à se faire sentir désagréablement. Ainsi, sur une vaste portion des mers et des océans, celle qui correspond aux "zones économiques exclusives", la Recherche est désormais soumise à autorisation que les États côtiers doivent "dans des circonstances normales" accorder si elle est poursuivie à des "fins exclusivement pacifiques et en vue d'accroître les connaissances scientifiques sur le milieu marin dans l'intérêt de l'humanité tout entière". [OCR NON CONTRÔLE]
La Lettre du Cnexo (Cnexo), 1980-09 , N. 3 , P. 1-6

Droits : Cnexo - Ifremer
http://archimer.ifremer.fr/doc/1980/publication-4774.pdf
http://archimer.ifremer.fr/doc/00000/4774/

Éditeur(s) : HAL CCSD Geological Society of America
Résumé : International audience
In this study, a novel application of a statistical approach is utilized for analysis of downhole logging data from Miocene-aged siliciclastic shelf sediments on the New Jersey Margin (eastern USA). A multivariate iterative nonhierarchical cluster analysis (INCA) of spectral gamma-ray logs from Integrated Ocean Drilling Program (IODP) Expedition 313 enables lithology within this siliciclastic succession to be inferred and, through comparison with the 1311 m of recovered core, a continuous assessment of depositional sequences is constructed. Signifi cant changes in INCA clusters corroborate most key stratigraphic surfaces interpreted from the core, and this result has particular value for surface recognition in intervals of poor core recovery. This analysis contributes to the evaluation of sequence stratigraphic models of large-scale clinoform complexes that predict depositional environments, sediment composition, and stratal geometries in response to sea-level changes. The novel approach of combining statistical analysis with detailed lithostratigraphic and seismic refl ection data sets will be of interest to any scientists working with downhole logs, especially spectral gamma-ray data, and also provides a reference for the strengths and weaknesses of multi component analysis applied to continental margin lithofacies. The method presented here is appropriate for evaluating successions elsewhere and also has value for hydrocarbon exploration where sequence stratigraphy is a fundamental tool.
EISSN: 1553-040X

insu-00858238
https://hal-insu.archives-ouvertes.fr/insu-00858238
DOI : 10.1130/GES00913.1