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) : Université des Antilles Études caribéennes
Résumé : L’organisation et la gestion des espaces publics en milieu urbain sont au centre des préoccupations de la puissance publique. Cet intérêt est lié dans les pays en développement aux nombreux dysfonctionnements recensés dans la ville. Ces difficultés sont entretenues par la démographie galopante, l’urbanisation informelle et à l’accroissement des activités industrielles, commerciales entre autres. À Dakar, la question de la mobilité urbaine est exacerbée par les puissants mouvements pendulaires entre la ville centrale et la périphérie amplifiés par les stationnements anarchiques et par l’inorganisation des modes de transports urbains.Le type d’espace public choisi pour cet article est une gare routière située au cœur du Plateau de Dakar : Petersen. Elle apparaît comme l’une des plus importantes gares routières du pays, surtout en matière de fréquentation avec plus de 50 000 personnes par jour. Le mode de gestion appliqué ici est la concession, une convention par laquelle la puissance publique confie la gestion de l’équipement à la SAGES une structure privée prenant en charge les intérêts parfois très contradictoires des différents acteurs.
The organization and management of public spaces in urban areas is a central concern of public authorities. This interest is linked in developing countries with numerous shortcomings identified in the city. These difficulties sustained by massive population growth, urbanization informal, and increased industrial activities, commercial and others. In Dakar, the question of urban mobility is exacerbated by the significant commuting between the city center and the periphery that are amplified by the chaotic parking lots and the disorganization of urban transport modes.The type of public space chosen for this article is a bus station in the heart of the Plateau de Dakar: Petersen. It appears as one of the largest bus stations in the country, especially in terms of attendance with over 50,000 people per day.The management method applied here is the concession, an agreement by which the public entrusts the management of equipment at the SAGES, a private organization that supports some very conflicting interests of different actors.
Sénégal
Dakar

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.7858
http://journals.openedition.org/etudescaribeennes/7858

Résumé : Au XXIème siècle, en France, en Martinique, au Québec, le monde du travail se caractérise encore par des inégalités professionnelles persistantes. La non mixité dans la fonction de direction générale ou autrement dit, la ségrégation verticale professionnelle dans l’entreprise serait-elle un invariant quels que soient les contextes ? Les référentiels culturels du dirigeant et du décideur demeurent encore masculins. Les représentations qui se sont construites sur les rôles sociaux des femmes et des hommes dans le travail se sont vite et durablement condensées en stéréotypes négatifs à l’égard des femmes.A partir de la théorie du noyau central d’Abric il semblait opportun de chercher à identifier les principaux déterminants qui ont présidé à la construction de ces stéréotypes. Ce noyau dur serait constitué de déterminismes historiques symboliques et sociaux. S’intéresser à la « déconstruction » des stéréotypes sexués en défaveur des femmes constitue un moyen de repenser l’action collective pour agir plus efficacement en matière de mixité professionnelle. En effet, plusieurs travaux ont montré que, sous certaines conditions, les éléments centraux d’une représentation pouvaient être sensibles à des informations venant les contredire. Réussir la mixité professionnelle entre les femmes et les hommes dans la fonction de direction générale des entreprises requiert, tant de la part de la politique gouvernementale que de celle des ressources humaines, des actions fortes relevant des enjeux de l’élimination des stéréotypes et de déconstruction du rôle social assigné à la femme depuis des millénaires.
In the 20th Century, in France, Martinique and Québec, the world of Work is still characterized by persistent professional disparities. Should the not-mixing be an invariant whatever the contexts, in the general managerial function, or in other words, the professional vertical segregation in the company ?The Manager’s and decider’s cultural reference tables remain still male. The representations built by themselves on the women and men social roles in work area are quickly and durably condensed in negative stereotypes against the women.From the theory of the central core of Abric (abric’score), it seems appropriate to try to identify the main determinants which presided over the construction of these stereotypes. This hard core would be constituted by symbolic and social historic determinism. Be interested in the "demolition" of the sexual stereotypes against the women establishes a way to rethink the collective action to act more effectively in regards to professional mixing. Indeed, several works showed that under certain conditions, the central elements of a representation could be sensitive to information coming to contradict them.To make a success of the professional mixing between the women and men in the general managerial function of companies requires so much on behalf of the government policy, a that of the human resources, strong actions raising stakes in the elimination of stereotypes and demolition of the social role assigned to the woman since millenniums.

http://www.theses.fr/2015AGUY0846/document

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 Elsevier
Résumé : International audience
The correlation between the flow turbulence and the performances of a ma- rine current turbine is studied. First, the incoming flow encountered in the flume tank is characterized in the framework of fully developed turbulent cascades in the inertial range. The Reynolds number, the Kolmogorov dissipation scale and the integral scale, are estimated from flow measurements. The intermittency of the turbulence is characterized in the lognormal multifractal framework, and the influence of the turbulent flow on the turbine power is assessed. The rotor speed control unit characteristics used for the turbine regulation induces non-negligible effects on the turbine behavior under fluctuations loads. Even if the power spectrum does not reveal any scale invariance, a multiscale analysis allows us to show the correlations between the turbulence time se- ries and the power produced. The classical Mean Square Coherency function shows that for scales larger than 10 seconds, the upstream velocity and power have large correlations. In the framework of the Empirical Mode Decomposition method, such correlations are studied using the time-dependence intrinsic corre- lation analysis method. This method allows to zoom into time-frequency scales where the flow perturbations induced some modifications in power production
ISSN: 0960-1481

hal-01528296
https://hal.archives-ouvertes.fr/hal-01528296
DOI : 10.1016/j.renene.2017.05.024

Éditeur(s) : HAL CCSD Mineralogical Society of America
Résumé : International audience
In situ mineralization of CO2 in ultramafic rock-hosted aquifers is one of the promising solutions for decreasing CO2 concentrations in the atmosphere. Naturally altered ultramafic rocks suggest that carbonation processes are controlled by local heterogeneities in the structure of the rock and fluid transport at the water-rock interfaces. We studied the role of rock crystallographic anisotropy relative to the global fluid flow direction on the mineralization of CO2 by means of electron microscope analyses from the macro- to the micrometer scale (EBSD-FIB). The sample used for the measurements was a hot pressed olivine core percolated by water enriched in CO2 (pCO2 = 10 MPa) at 180 °C. During the percolation experiment, olivine was dissolved and two types of carbonates, dolomite, and magnesite, were precipitated on olivine surfaces. The results showed that the dissolution of olivine is controlled by its crystallographic properties as shown by the development of etch-pits only on the (010)ol planes and with elongated shapes parallel to the [010]ol axes. In contrast, the precipitation of carbonates is governed by hydrodynamic properties. Carbonates are heterogeneously distributed in the percolated rock. They are mainly located along the moderate (for dolomite) and the minor (for magnesite) flow paths, both oriented parallel to the principal fluid flow direction, which allow carbonates to be supplied with divalent cations (e.g., Ca2+, Mg2+, and Fe2+). In these flow paths, carbonate growth is systematically oriented normal to the flow that facilitates the development of chemical gradients with cationic supersaturation conditions for carbonate precipitation near the walls.In natural systems, the (010)ol planes are parallel to the Moho and the (100)ol planes are vertical; our study suggests that flow of CO2-rich fluids will induce precipitation of carbonates localized along, and preferentially clogging, vertical flow paths while favoring olivine dissolution along horizontal fluid pathways. This dual control of structure and fluid flow on carbonation mechanisms could be an important parameter allowing sustainable CO2 storage in peridotites, while limiting the risks of leakage toward the surface.
ISSN: 0003-004X

hal-01143393
https://hal.archives-ouvertes.fr/hal-01143393
DOI : 10.2138/am-2015-4913

Éditeur(s) : HAL CCSD
Résumé : The northern Mirdita ophiolite massifs in Albanian Dinarides formed at a slow-spreading ridge, active during the Jurassic (160–165 Ma). They share a common horizontal Jurassic–Lower Cretaceous sedimentary cover showing that they were not deeply and intrinsically affected by later Alpine thrusting. The western massifs of Mirdita, first oceanic core complex (OCC) and detachment shear zone described in ophiolites, compare with OCCs in slow-spreading ridges and provide continuous exposure of the deep internal structure of this system, revealing its kinematics, thanks to detailed structural mapping in peridotites and gabbros. The Mirdita detachments root in the Moho transition zone (MTZ), a weak zone at the top of asthenospheric mantle, where basaltic melts impregnate dunites. The OCC domes are plagioclase-amphibole–bearing mylonitic peridotites, ∼400 m thick, grading downward within 200 m to harzburgitic mantle. The mylonitic detachments crossed Moho beneath a NNE-SSW–trending ridge. On the western side of OCC domes, the hanging wall of the ridge, crustal gabbros, and basalts are still preserved, despite being deeply affected by hydrothermal alteration. From there, the partially molten MTZ was detached as a shear zone, mixing with lower gabbros. The OCC emerged, migrating upsection and eastward over 5 km. Finally, the OCC front is observed in hornblende-rich syntectonic mylonites derived from upper gabbros and from the overlying former lid. Serpentinization is static within these mylonites. A low-temperature detachment fault is expressed as a sheared antigoritic mélange at the margin of the mylonitic shear zone. Asthenospheric flow in the harzburgitic mantle beneath the ridge of origin has been preserved below the OCC rooting. The dominant asthenospheric flow direction trends parallel to the ridge axis. This mantle flow rotates over 200 m into the low-temperature mylonitic detachments, where OCC motion turns transversal to the ridge. Crystal preferred orientation measurements on six samples point to brown hornblende crystal growth during mylonitic flow and illustrate the change of olivine intra-crystalline slip system in mylonites compared to porphyroclastic harzburgite.
ISSN: 1553-040X

hal-01504440
https://hal.archives-ouvertes.fr/hal-01504440
DOI : 10.1130/GES01383.1

Résumé : L’arc des Petites Antilles résulte de la lente subduction vers l'Ouest des plaques Nord et Sud-Américaines sous la plaque Caraïbes (2cm/an). A la latitude de l’archipel guadeloupéen et à ~150 km à l’Ouest du front de déformation, le bassin d'avant-arc de Marie-Galante forme un bassin perché, incliné vers la fosse et limité vers l’Est par un haut-fond, l’Eperon Karukéra. À cette latitude, le bassin de Marie-Galante domine le prisme d’accrétion de la Barbade et fait face à la ride de Tiburon qui balaye la zone du Nord au Sud depuis la fin du Miocène supérieur. Le remplissage sédimentaire du Bassin de Marie-Galante montre des déformations actives au moins depuis ~30 millions d’années. L’objectif du travail est de reconstituer l’évolution tectono-sédimentaire de ce bassin pour apporter de nouvelles contraintes sur la compréhension globale de la zone de subduction frontale des Petites Antilles. Ce travail s'appuie sur les données de bathymétrie multifaisceaux et de sismique réflexion multi-traces haute résolution acquises lors des campagnes du programme KaShallow. Cette base de données, complétée de profils sismiques plus basse résolution de campagnes antérieures, permet d’avoir une couverture pseudo 3D et à quatre échelles de résolution de l'ensemble du bassin. Un échantillonnage par ROV et carottage ciblé a fourni 40 prélèvements dans les principales unités sismiques. Les analyses pétrologiques et les datations biostratigraphiques autorisent des reconstitutions paléo-environnementales depuis le Paléogène supérieur jusqu’à Actuel. L’interprétation sismique multi-échelle montre un bassin sédimentaire atteignant ~4,5s temps double (~4500 à 5625 m) sur un substratum magmatique pré-structuré. Ce bassin est composé de 5 grands ensembles sédimentaires (E-1, E1, E2, E3 et E4) subdivisés en 13 unités limitées par 14 surfaces de discontinuités. L’organisation séquentielle des unités sismiques permet de mettre en évidence 10 séquences de dépôts de troisièmes ordres (S-1 à S9). Le calage biostratigraphique de l’ensemble des séquences permet de proposer une évolution tectono-sédimentaire du bassin de l’Éocène à l’Actuel. Ainsi, nous distinguons quatre systèmes de failles normales associées à trois phases d’extensions qui contrôlent l’évolution architecturale et sédimentaire du bassin. 1/ Un système N050±10°E hérité, actif dès le Paléogène supérieur, qui contrôle le basculement général du bassin vers le SSE. Il est responsable de la formation de l'escarpement de Désirade d’environ 4500 m de dénivelé. Cette première extension est interprétée comme résultant de la fragmentation de l'avant-arc en réponse à l'augmentation du rayon de courbure de la zone de subduction. 2/ Un système N130°-N150°E, structurant à l’échelle de l’Éperon Karukéra, qui contrôle la sédimentation dès le Miocène inférieur et marque une première phase d'extension transverse à l’arc. 3/ Un système N160°-N180°E qui segmente le Bassin de Marie-Galante en un sous-bassin à l'Ouest et l'Éperon Karukéra à l'Est. Cette seconde extension, globalement perpendiculaire à la marge, s'accompagne d’une subsidence et d'une inversion de la polarité du bassin en réponse à son basculement vers la fosse qui débute au cours du Miocène moyen et se poursuit actuellement à l'Est du bassin. Cette évolution à long terme de l'avant-arc, concomitante avec le recul de l'arc volcanique vers l’Ouest, est considérée comme résultant d’une érosion basale de la plaque supérieure. 4/ Un système N090±10°E plus tardif est localisé au centre du bassin et qui contrôle le développement de plates-formes carbonatées néritiques sur certaines têtes de blocs, comme par exemple à Marie-Galante. Cette dernière extension, parallèle à l’arc, se manifeste dans le bassin à partir du Pliocène inférieur. Elle se superpose au régime d'extension perpendiculaire à l'avant-arc et est interprétée comme l'accommodation du partitionnement de la déformation en réponse à l’obliquité croissante du front subduction vers le Nord.
The Lesser Antilles result of the slow westward subduction of the North and South American plate under the Caribbean plate (2 cm / year). At the latitude of the Guadeloupe archipelago and ~ 150 km to the west of the deformation front, the fore-arc basin of Marie-Galante forms a perched basin tilted to the pit and limited to the East by a shoal, the Spur Karukéra. At this latitude, Marie-Galante basin dominates the accretionary prism of Barbados and faces wrinkle Tiburon sweeping the area from North to South from the late Miocene. The sedimentary fill Basin Marie-Galante shows active deformation since at least ~ 30 million years. The aim of the work is to reconstruct the tectono-sedimentary evolution of the basin to provide new constraints on the overall understanding of the frontal subduction zone Lesser Antilles. This work relies on multibeam bathymetry data and high-resolution seismic reflection multi-traces acquired during campaigns KaShallow program. This database, supplemented by lower resolution of previous campaigns seismic profiles, provides a pseudo-3D coverage and four scales of resolution of the entire basin. ROV sampling and targeted core provided 40 samples in the main seismic units. Petrological analysis and biostratigraphic dating allow paleoenvironmental reconstructions from the upper Paleogene up Actuel. Seismic interpretation multiscale shows a sedimentary basin reaching ~ 4,5s double (~ 4500-5625 m) on a substrate pre-structured magma. This basin consists of 5 main sedimentary units (E-1, E1, E2, E3 and E4) divided into 13 units bounded by discontinuities 14 surfaces. The sequential organization of seismic units allows to highlight sequences 10 deposits of third order (S-1 to S9). The biostratigraphic calibration of all sequences able to offer a tectono-sedimentary evolution of the Eocene basin to Present. Thus, we distinguish four normal fault systems associated with three phases of extensions that control the architectural and sedimentary evolution of the basin. 1 / A system N050 ± 10 ° E inherited assets from the upper Paleogene, which controls the overall pelvic tilt towards the SSE. He is responsible for the formation of the escarpment Désirade about 4500 m elevation. The first extension is interpreted as resulting from the fragmentation of the fore-arc in response to the increase in the radius of curvature of subduction. 2 / A system N130 ° -N150 ° E, structuring across the Spur Karukéra, which controls sediment from the Miocene and marks the first phase of transverse extension arc. 3 / A system N160 ° E ° -N180 which segments Basin Marie-Galante in a sub-basin to the west and the Spur Karukéra in the East. This second extension, generally perpendicular to the margin, is accompanied by subsidence and reversing the polarity of the basin in response to his switch to the pit, beginning during the Middle Miocene and is ongoing in the East the basin. This long-term evolution of the forearc, concurrent with the decline in volcanic arc to the west, is considered as resulting from a basal erosion of the top plate. 4 / A system N090 ± 10 ° later E is located in the center of the basin and controlling the development of neritic carbonate platforms on certain blocks heads, such as Marie-Galante. This latest extension, parallel to the arc occurs in the basin from the lower Pliocene. It is superimposed on the expansion plan perpendicular to the fore-arc and is interpreted as the accommodation of the partitioning of deformation in response to the increasing obliquity front subduction north.

http://www.theses.fr/2014AGUY0799/document

Éditeur(s) : Oxford Univ Press Inc
Résumé : Since the transition from terrestrial to marine environments poses strong osmoregulatory and energetic challenges, temporal and spatial fluctuations in oceanic salinity might influence salt and water balance (and hence, body condition) in marine tetrapods. We assessed the effects of salinity on three species of sea snakes studied by mark-recapture in coral-reef habitats in the Neo-Caledonian Lagoon. These three species include one fully aquatic hydrophiine (Emydocephalus annulatus), one primarily aquatic laticaudine (Laticauda laticaudata), and one frequently terrestrial laticaudine (Laticauda saintgironsi). We explored how oceanic salinity affected the snakes' body condition across various temporal and spatial scales relevant to each species' ecology, using linear mixed models and multimodel inference. Mean annual salinity exerted a consistent and negative effect on the body condition of all three snake species. The most terrestrial taxon (L. saintgironsi) was sensitive to salinity over a short temporal scale, corresponding to the duration of a typical marine foraging trip for this species. In contrast, links between oceanic salinity and body condition in the fully aquatic E. annulatus and the highly aquatic L. laticaudata were strongest at a long-term (annual) scale. The sophisticated salt-excreting systems of sea snakes allow them to exploit marine environments, but do not completely overcome the osmoregulatory challenges posed by oceanic conditions. Future studies could usefully explore such effects in other secondarily marine taxa such as seabirds, turtles, and marine mammals.
Integrative And Comparative Biology (1540-7063) (Oxford Univ Press Inc), 2012-08 , Vol. 52 , N. 2 , P. 235-244

Droits : The Author 2012. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved.
http://archimer.ifremer.fr/doc/00089/20064/20739.pdf
DOI:10.1093/icb/ics081
http://archimer.ifremer.fr/doc/00089/20064/

Éditeur(s) : Public Library Science
Résumé : Observing spatial and temporal variations of marine biodiversity from non-destructive techniques is central for understanding ecosystem resilience, and for monitoring and assessing conservation strategies, e.g. Marine Protected Areas. Observations are generally obtained through Underwater Visual Censuses (UVC) conducted by divers. The problems inherent to the presence of divers have been discussed in several papers. Video techniques are increasingly used for observing underwater macrofauna and habitat. Most video techniques that do not need the presence of a diver use baited remote systems. In this paper, we present an original video technique which relies on a remote unbaited rotating remote system including a high definition camera. The system is set on the sea floor to record images. These are then analysed at the office to quantify biotic and abiotic sea bottom cover, and to identify and count fish species and other species like marine turtles. The technique was extensively tested in a highly diversified coral reef ecosystem in the South Lagoon of New Caledonia, based on a protocol covering both protected and unprotected areas in major lagoon habitats. The technique enabled to detect and identify a large number of species, and in particular fished species, which were not disturbed by the system. Habitat could easily be investigated through the images. A large number of observations could be carried out per day at sea. This study showed the strong potential of this non obtrusive technique for observing both macrofauna and habitat. It offers a unique spatial coverage and can be implemented at sea at a reasonable cost by non-expert staff. As such, this technique is particularly interesting for investigating and monitoring coastal biodiversity in the light of current conservation challenges and increasing monitoring needs.
Plos One (1932-6203) (Public Library Science), 2012-02 , Vol. 7 , N. 2 , P. -

Droits : 2012 Pelletier et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License
http://archimer.ifremer.fr/doc/00078/18879/16453.pdf
DOI:10.1371/journal.pone.0030536
http://archimer.ifremer.fr/doc/00078/18879/

Éditeur(s) : HAL CCSD American Association for the Advancement of Science
Résumé : International audience
Sediments cored along the southwestern Iberian margin during Integrated Ocean Drilling Program Expedition 339 provide constraints on Mediterranean Outflow Water (MOW) circulation patterns from the Pliocene epoch to the present day. After the Strait of Gibraltar opened (5.33 million years ago), a limited volume of MOW entered the Atlantic. Depositional hiatuses indicate erosion by bottom currents related to higher volumes of MOW circulating into the North Atlantic, beginning in the late Pliocene. The hiatuses coincide with regional tectonic events and changes in global thermohaline circulation (THC). This suggests that MOW influenced Atlantic Meridional Overturning Circulation (AMOC), THC, and climatic shifts by contributing a component of warm, saline water to northern latitudes while in turn being influenced by plate tectonics.
ISSN: 0036-8075

hal-01054316
https://hal.archives-ouvertes.fr/hal-01054316
DOI : 10.1126/science.1251306

Éditeur(s) : HAL CCSD
Résumé : High Pressure - Low Temperature (HP-LT) rocks testify for burying and exhumation of crustal material in subduction zones. Their complete exhumation is the result of processes acting during (syn-orogenic) and after (post-orogenic) subduction is active, the latter partly obliterating the first. In the Aegean domain, the Attic-Cycladic Blueschist unit (ACBU) is a HP-LT unit exhumed in metamorphic core complexes (MCCs) in the back-arc domain of the Hellenic subduction zone. This study is an attempt to distinguish features related to syn-orogenic exhumation processes responsible for the first stages of exhumation This syn-orogenic "message" has to be read through the post-convergence structural and thermal overprint that accompanied the formation of the MCCs. Particularly, the geometry, the timing and the amount of the syn-orogenic exhumation has to be determined. We investigate these features with coupled field, metamorphic petrology and radiochronology studies First, based on observations on Ios (southern Cyclades), it has recently been proposed that syn-orogenic exhumation of the ACBU was accommodated by a basal thrust over the Cycladic Basement (CB) [Huet, et al., 2009]. The peak conditions, deduced from pseudosections calculation for the Ios main lithologies, are 500 °C-19 kbar for the ACBU and 550 °C-16 kbar for the CB. Exhumation until 400 °C-8 kbar is considered as syn-orogenic. Second, phengites populations, single grains and in situ 40Ar-39Ar geochronology has been carried out on samples from Tinos and Andros (northern Cyclades), Syros (central Cyclades) and Ios. The results gather in several clusters: 50-55 Ma, 40-45 Ma, 30-35 Ma, and 22-26 Ma. Based on these new P-T-t data and a synthesis of published data, we are able to refine the geometry and the timing of the exhumation of the ACBU. Data from the whole Cyclades exhibit little differences in ages and P-T conditions for the successive stages of exhumation. The peak of pressure (500±50 °C-18±1 kbar) has been reached at 50-55 Ma from Tinos to Ios. The onset of the exhumation occurred at 40-45 Ma in blueschist facies conditions, between a thrust at their bottom and a detachment at their top. The following decompression was accompanied by cooling until 30-35 Ma (400±50 °C-8±1 kbar). At that time, the boundary conditions switched to extension. Finally, we propose a model for the exhumation of HP-LT units accounting for these data. We also consider the rheological implications of the syn-orogenic structuration of the Aegean wedge on the post-orogenic evolution. B. Huet, L. Labrousse, and L. Jolivet [2009] Thrust or detachment? Exhumation processes in the Aegean: Insight from a field study on Ios (Cyclades, Greece), Tectonics, 28, 3, doi:10.1029/2008TC002397.
EGU General Assembly
Vienne, Austria

insu-00839054
https://hal-insu.archives-ouvertes.fr/insu-00839054
BIBCODE : 2010EGUGA..1214098H

Éditeur(s) : HAL CCSD
Résumé : This historical perspective provides an overall view of the main steps that led to the acceptance of the concept of mantle exhumation accompanying lithosphere stretching and extreme crustal thinning. We first remember that the presence of exposures of mantle rocks along oceanic spreading ridges was early reported in the 60's due to the results of sediment cores and dredge hauls collected along the Mid-Atlantic Ridge. In the meantime, detailed analysis of the relationships between oceanic sediments of Late Jurassic age and their primary basement in the Apennine ophiolites led many authors to point to the importance of exhumation of mantle rocks on ancient seafloors. By contrast to the thick sections of classical ophiolites (e.g. Oman), the Alpine-Corsican-Appennine ophiolites are characterized by a relatively small amount of mafic rocks (gabbros and basalts), by the absence of any sheeted dyke complex and by the frequent occurrence of oceanic sediments stratigraphically overlying mantle-derived peridotites and associated gabbroic intrusions. They display some of the characteristics of slow-spreading ridge systems, but, due to their highly tectonized character, they have been interpreted successively either as remnants of oceanic fracture zones of normal ocean or as remnants of very-poorly organized, abnormal oceanic basement. This review shows how the concept of mantle exhumation has been elaborated more or less in the same period both by marine geoscientists and by geologists conducting investigations in ophiolitic units of the Alps-Apennines mountain belt. Dredging and diving results from the Gorringe Bank, the Iberia margin, the Thyrrenian Sea and the Central Atlantic in the 1980's and 1990's provided additional proofs that the mantle is currently exhumed in various oceanic environments, including distal continental margins, back-arc basins and slow-spreading ridges of wide oceans. It is shown finally how renewed cross-information from mountain belts and the oceans, multiplying the examples of sedimentary reworking of mantle material, help better constrain the mechanisms of mantle exhumation. This mechanism progressively appeared as a fundamental step during the processes of extension of both continental and oceanic lithospheres in numerous geological situations worldwide.
Bollettino della Società Geologica Italiana

hal-00475653
https://hal.archives-ouvertes.fr/hal-00475653
DOI : 10.3301/IJG.2009.128.2.279

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The marine Messinian deposits of Tunisia cover a narrow littoral strip some 300 km long between the northern Bizerte and Cap Bon areas and the central-eastern Sahel region. Litho- and biofacies analysis of six stratigraphic sections reveals the distinctive features of these deposits.;The lower Messinian deposits are characterized by ubiquitous siliciclastics and abundant oolitic/bioclastic limestones organized in an eastward facing ramp. Westward (landward), this ramp changes into coastal lagoons, sometimes containing evaporites. Eastward, the ramp passes to the reefal Pelagian Platform extending as far as Lampedusa.;Two main sedimentary cycles are distinguished: 1) an early Messinian siliciclastic retrogradational then oolitic/bioclastic progradational cycle (Beni Khiar Formation and lower Oued bel Khedim Formation): 2) a late Messinian brackish to continental cycle that probably accumulated in rapidly subsiding lagoons (Cued el Bir Formation and upper Oued bel Khedim Formation). The Tunisian early Messinian cycle is partly eustatically controlled, but the late Messinian cycle cannot be confidently correlated to other well-known Messinian series because of tectonic movements.;The lower Messinian deposits of Tunisia are also characterized by abundant suspension-feeding organisms (molluscs and bryozoans) and rare corals, calcareous algae, echinoids, and larger benthic foraminifers. The proposed palaeoenvironmental model shows that the lower Messinian ramp of Tunisia was located on a current-protected margin and subjected to continent-derived sediment and nutrient supply. Eastward, nutrient influx diminished and a shallow-water isolated carbonate platform with coralgal facies developed between the western and the eastern Mediterranean basins. The main hydrological connection between these two basins occurred through a narrow seaway situated to the northeast of the Pelagian Platform, south of Sicily and Malta.
ISSN: 0031-0182

hal-00475583
https://hal.archives-ouvertes.fr/hal-00475583
DOI : 10.1016/j.palaeo.2009.10.028

Éditeur(s) : Neidine editeurs
Résumé : The publication draws up a balance sheet about the natural marine assets of New Caledonia by distinguishing the coast and the intertidal zones, the coral reefs and lagoons, the open sea or "deep blue". A set of assets relative to the living and mineral natural resources, to the characteristics of the shallow and deep marine biodiversity, to the potential marine energy resources are discussed. This publication, edited in a Consumer directed free magazine, draws up a set of perspectives relative to a blue economy to be built in a country still very centred on its ground resources, essentially the nickel mining industry.
Le dossier dresse un bilan des atouts naturels de la nouvelle-Calédonie en matière marine en distinguant le littoral et l'intertidal, les récifs et lagons, la mer ouverte ou "grand bleu". Sont discutés un ensemble d'atouts relatifs aux ressources naturelles vivantes et minérales, aux caractéristiques de la biodiversité marine peu profonde et semi profonde, aux ressources énergétiques potentielles.Cette publication, éditée dans une revue orientée Grand Public, dresse un ensemble de perspectives relatives à une économie bleue à construire dans un pays encore très axé sur ses ressources terrestres, essentiellement l'industrie minière de nickel.
Taï Kona (2269-7535) (Neidine editeurs), 2013-03 , N. 1 , P. 12-25

Droits : Tai Kona
http://archimer.ifremer.fr/doc/00142/25350/23432.pdf
http://archimer.ifremer.fr/doc/00142/25350/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Le milieu marin de la Mer des Caraïbes est composé de trois écosystèmes principaux : les récifs coralliens, les mangroves et les herbiers, qui abritent une faune et une flore exceptionnelles. Mais l’équilibre fragile de ces espaces est menacé par les nombreuses activités humaines qui les dégradent progressivement. Face aux enjeux socio-économiques qu’ils représentent pour les pays caribéens, ces derniers ont établi un cadre juridique à l’échelle régionale pour la protection et la gestion de leur ressource marine, la Convention de Carthagène. Après avoir dressé un tableau de la situation environnementale des principaux écosystèmes marins caribéens, il convient de faire un point sur les modes de gestion mis en œuvre pour les préserver.
The marine environment of the Caribbean Sea is composed primarily of three main ecosystems: coral reefs, mangroves and seagrasses, home to fauna and flora. But the delicate balance of these areas is threatened by many human activities that deteriorate gradually deteriorated them. Deal with socio-economic issues around these resources, Caribbean countries have established a legal framework at the regional level to ensure the protection and management of marine resources (the Cartagena Convention). After drawing up an overview of the environmental situation of the main Caribbean marine ecosystems, it should present the management mode adopted to preserve them.
Caraïbes

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.4343
http://journals.openedition.org/etudescaribeennes/4343

Éditeur(s) : HAL CCSD Springer International Publishing AG.
Résumé : International audience
Underwater Seascapes. From geographical to ecological perspectives

hal-01429034
https://hal.archives-ouvertes.fr/hal-01429034
DOI : 10.1007/978-3-319-03440-9_16

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : International audience
The present study proposes to estimate the influence of climate, eustatism and local tectonics on the sedimentation of a basin margin at the syn-rift to post-rift transition. For that, paleomagnetic measurements were performed on a marine marly-calcareous sedimentary succession ranging from Upper Oligocene to Lower Miocene and located on the northern margin of the Liguro-Provençal basin. The magnetostratigraphic record is correlated to the reference geomagnetic polarity scale [ATNTS04, Lourens et al. 2004] with the help of biostratigraphy based on calcareous nannofossils and planctonic foraminifers [Oudet et al., 2010]. The resulting age model shows that the 100 m-thick sedimentary succession covers a time span of 5 m.y. from the Late Chattian to the Early Burdigalian. Despite several exposure surfaces and a change in the sedimentation rate, no significant hiatus of sedimentation is documented. In addition, we also estimate the paleoenvironmental evolution through the sedimentary succession. Comparing the dated paleoenvironmental reconstruction with global {delta}18O and sea level curves [Miller et al., 2005], we show that the Carry-le-Rouet succession is an excellent paleoclimatic archive. Indeed, coral reefs developed at the glacial-interglacial stage transition marking the end of the Oligocene. In addition, the most diversified coral reefs occurred during the warmest period of the Aquitanian. During rifting, bathymetric variations recorded in the studied succession are related to local synsedimentary tectonics whereas, during oceanic crust accretion, global sea level changes influence the sedimentation. This result allows to characterise and to accurately date the break-up unconformity at 20.35 Ma.
EISSN: 1777-5817

hal-00619040
https://hal.archives-ouvertes.fr/hal-00619040
DOI : 10.2113/gssgfbull.182.1.37

Éditeur(s) : Public Library Science
Résumé : Background: Resolving threats to widely distributed marine megafauna requires definition of the geographic distributions of both the threats as well as the population unit(s) of interest. In turn, because individual threats can operate on varying spatial scales, their impacts can affect different segments of a population of the same species. Therefore, integration of multiple tools and techniques - including site-based monitoring, genetic analyses, mark-recapture studies and telemetry - can facilitate robust definitions of population segments at multiple biological and spatial scales to address different management and research challenges. Methodology/Principal Findings: To address these issues for marine turtles, we collated all available studies on marine turtle biogeography, including nesting sites, population abundances and trends, population genetics, and satellite telemetry. We georeferenced this information to generate separate layers for nesting sites, genetic stocks, and core distributions of population segments of all marine turtle species. We then spatially integrated this information from fine-to coarse-spatial scales to develop nested envelope models, or Regional Management Units (RMUs), for marine turtles globally. Conclusions/Significance: The RMU framework is a solution to the challenge of how to organize marine turtles into units of protection above the level of nesting populations, but below the level of species, within regional entities that might be on independent evolutionary trajectories. Among many potential applications, RMUs provide a framework for identifying data gaps, assessing high diversity areas for multiple species and genetic stocks, and evaluating conservation status of marine turtles. Furthermore, RMUs allow for identification of geographic barriers to gene flow, and can provide valuable guidance to marine spatial planning initiatives that integrate spatial distributions of protected species and human activities. In addition, the RMU framework - including maps and supporting metadata - will be an iterative, user-driven tool made publicly available in an online application for comments, improvements, download and analysis.
Plos One (1932-6203) (Public Library Science), 2010-12 , Vol. 5 , N. 12 , P. -

Droits : 2010 Plos One
http://archimer.ifremer.fr/doc/00028/13926/11308.pdf
DOI:10.1371/journal.pone.0015465
http://archimer.ifremer.fr/doc/00028/13926/

Éditeur(s) : HAL CCSD University of Uludag
Résumé : International audience
The aim of this study was to compare the core temperature (TC) and markers of hydration status in athletes performing a half Ironman triathlon race in hot and humid conditions (27.2 ± 0.5°C, relative humidity was 80 ± 2%). Before and immediately after the 2012 Guadeloupe half Ironman triathlon, body mass and urine osmolality (mean ± SD) were measured in 19 well-trained male triathletes. TC was measured before and after the race, and at each transition during the event, using an ingestible pill telemetry system. Ambient temperature and heart rate (HR) were measured throughout the race. Mean ± SD performance time was 331 ± 36 minutes and HR was 147 ± 16 beats·min-1. Wet bulb globe temperature (WBGT) averaged 25.4 ± 1.0°C and ocean temperature was 29.5°C. The average TC at the beginning of the race (TC1) was 37.1 ± 0.7°C; it was 37.8 ± 0.9°C after swimming (TC2), 37.8 ± 1.0°C after cycling (TC3), and (TC4) 38.4 ± 0.7°C after running. Body mass significantly declined during the race by 3.7 ± 1.9 kg (5.0 ± 2.4%; p < 0.05), whereas urine osmolality significantly increased from 491.6 ± 300.6 to 557.9 ± 207.9 mosm·kg-1 (p < 0.05). Changes in body mass were not related to finishing TC or urine osmolality. Ad libitum fluid intake appears applicable to athletes acclimatized to tropical climate, when performing a half Ironman triathlon in in a warm and humid environment.
ISSN: 1303-2968

hal-01152333
https://hal.univ-antilles.fr/hal-01152333