Éditeur(s) : HAL CCSD
Résumé : Differentiation of the lithospheric mantle occurred principally through partial melting and extraction of melts. Harzburgites are generally considered as melting residues whereas lherzolites are regarded as pristine mantle weakly affected by melting. However, some orogenic peridotites show evidence of igneous refertilization. In this context, this work re-investigates the nature of the Lherz lherzolites (Pyrenees), type-locality of lherzolites, described as a piece of preserved fertile mantle. Structural and geochemical data show that these lherzolites are not pristine but formed through a refertilization reaction between MORB-like melts and refractory lithosphere. Moreover, the Lherz peridotites were partly used to infer the composition of the primitive upper mantle and these results may have important implications for the nature of the late veneer. Additionally, crystal-preferred orientations of minerals (CPO) highlight a strong feedback between melt percolation and finite strain in the percolated rocks. CPO variations are ruled by a subtle balance between instantaneous melt fraction and local strain rate. This work also investigated the effect of melt percolation on Hf, Nd and Sr isotopes. Isotope systematics in Lherz shows that strong isotopic decoupling may arise in a percolation front. The modelling suggests that decoupled isotopic signatures are generated during porous flow and governed by the melt/matrix elements concentrations, chemical diffusivities or efficiency of isotopic homogenization. Melt-rock interactions can generate “intraplate-like” isotopic signatures. This suggests that a part of isotopic signatures of mantle-related rocks could be generated by diffusional processes associated with melt transport.
La différenciation du manteau lithosphérique s'est principalement effectuée par fusion partielle et extraction de magmas. Les harzburgites sont généralement considérées comme des résidus de fusion tandis que les lherzolites représentent un manteau originel peu affecté par la fusion. Cependant, certaines péridotites orogéniques montrent des évidences de refertilisation magmatique. Dans ce contexte, ce travail remet en cause la nature primitive des lherzolites de Lherz (Pyrénées), lithotype de la lherzolite. Les données structurales et géochimiques montrent que ces lherzolites ne représentent pas du manteau préservé mais qu'elles se sont formées par une réaction de refertilisation entre un liquide de type MORB et une lithosphère réfractaire. De plus, les orientations préférentielles de réseau (OPR) des minéraux montrent une forte interdépendance entre la percolation magmatique et la déformation finie observée dans les roches percolées. Les variations d'OPR semblent contrôlées par un équilibre subtil entre fraction de liquide instantanée et taux de déformation local. Ce travail a également abordé les effets de la percolation magmatique sur la variabilité isotopique des roches mantelliques. Les résultats montrent qu'un fort découplage isotopique peut s'observer dans un front de percolation. Les modèles suggèrent que le découplage des signatures isotopiques se produit pendant la percolation, gouverné par le rapport des concentrations en éléments (magma/matrice), la diffusivité et le processus d'homogénéisation isotopique. Les réactions magma/roche peuvent générer des signatures isotopiques de type intraplaque. Ceci suggère qu'une part des signatures isotopiques des roches ou laves dérivées du manteau pourrait être produite par des processus diffusionnels associés à du transport de magma.
https://tel.archives-ouvertes.fr/tel-00431325

tel-00431325
https://tel.archives-ouvertes.fr/tel-00431325
https://tel.archives-ouvertes.fr/tel-00431325/document
https://tel.archives-ouvertes.fr/tel-00431325/file/theseleroux08.pdf

Éditeur(s) : HAL CCSD Pergamon
Résumé : This paper presents an experimental study of the deformation of Beaucaire marl subjected to drained triaxial tests under a wide range of confining pressure. Several methods of observation have been used: X-ray computed tomography, scanning electronic microscopy, quantitative image analysis of thin sections and mercury porosimetry. The analysis at the grain scale shows the existence of various deformation modes depending on the mean stress level. These modes are classified with reference to the brittle and ductile regimes. In specimens deformed under low confining pressure, macro-cracks are localised in a band more contracting than the rest of the specimen. In specimens deformed under moderate confining pressure, a series of micro-scale shear bands characterised by a grain re-orientation towards the direction of macro-shear is detected in the zones of localised deformation. The material in between the micro-scale shear bands is contracting more than the rest of the specimen in some cases; in other cases, a schistosity is detected also in the rest of the specimen outside the localisation zones. In the specimen deformed under high confining pressure, no localisation occurs, and a schistosity is observable throughout the specimen.
ISSN: 1365-1609

hal-00411208
https://hal.archives-ouvertes.fr/hal-00411208
DOI : 10.1016/j.ijrmms.2007.08.007

Éditeur(s) : HAL CCSD
Résumé : International audience
Abstract A careful re-examination of the well-known written documents pertaining to the 2,750-year-long historical period of Mount Etna was carried out and their interpretation checked through the high-accuracy archeomagnetic method (>1,200 large samples), combined with the 226Ra-230Th radiochronology. The magnetic dating is based upon secular variation of the direction of the geomagnetic field (DGF) and estimated to reach a precision of  ±40 years for the last 1,200 years, and ±100 to 200 years up to circa 150 B.C. Although less precise, the 226Ra-230Th method provides a unique tool for distinguishing between historic and prehistoric lavas, which in some cases might have similar DGFs. We show that despite the abundance of details on ancient historical eruptions, the primary sources of information are often too imprecise to identify their lava flows and eruptive systems. Most of the ages of these lavas, which are today accepted on the geological maps and catalogues, were attributed in the 1800s on the basis of their morphology and without any stratigraphical control. In fact, we found that 80% of the “historically dated” flows and cones prior to the 1700s are usually several hundreds of years older than recorded, the discrepancies sometimes exceeding a millennium. This is proper the case for volcanics presumed of the “1651 east” (actually ∼1020), “1595” (actually two distinct flows, respectively, ∼1200 and ∼1060), “1566” (∼1180), “1536” (two branches dated ∼1250 and ∼950), “1444” (a branch dated ∼1270), “1408” (lower branches dated ∼450 and ∼350), “1381” (∼1160), “1329” (∼1030), “1284” (∼1450 and ∼700), “1169 or 812” (∼1000) eruptions. Conversely, well-preserved cones and flows that are undated on the maps were produced by recent eruptions that went unnoticed in historical accounts, especially during the Middle Ages. For the few eruptions that are recorded between A.D. 252 and 750 B.C., none of their presumed lava flows shows a DGF in agreement with that existing at their respective dates of occurrence, most of these flows being in fact prehistoric. The cinder cones of Monpeloso (presumed “A.D. 252”) and Mt. Gorna (“394 B.C.”), although roughly consistent magnetically and radiochronologically with their respective epochs, remain of unspecified age because of a lack of precision of the DGF reference curve at the time. It is concluded that at the time scale of the last millennia, Mount Etna does not provide evidence of a steady-state behavior. Periods of voluminous eruptions lasting 50 to 150 years (e.g., A.D. 300–450, 950–1060, 1607–1669) are followed by centuries of less productive activity, although at any time a violent outburst may occur. Such a revised history should be taken into account for eruptive models, magma output, internal plumbing of the volcano, petrological evolution, volcano mapping and civil protection.
Bulletin of Volcanology / Bull Volcanic Eruptions

hal-00315967
https://hal.archives-ouvertes.fr/hal-00315967
DOI : 10.1007/s00445-007-0121-x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
New investigations in the Neogene Boudinar basin (Morocco) provide new information about the Messinian Salinity Crisis (MSC) and Zanclean reflooding in the southern part of the Alboran realm (westernmost Mediterranean). Based on a new field, sedimentological and palaeontological analyses, the age and the geometry of both the Messinian erosional surface (MES) and the overlying deposits have been determined. The MES is of late Messinian age and was emplaced in subaerial settings. In the Boudinar basin, a maximum of 200 m of Miocene sediments was eroded, including late Messinian gypsum blocks. The original geometry of the MES is preserved only when it is overlain by late Messinian continental deposits, conglomeratic alluvial fans or lacustrine marly sediments. These sediments are interpreted as indicators of the sea-level fall during the MSC. Elsewhere in the basin, the contact between late Messinian and early Pliocene deposits is a low-angle dipping, smooth surface that corresponds to the early Pliocene transgression surface that subsequently re-shaped the regressive MES. The early Pliocene deposits are characterized by: (i) their onlap onto either the basement of the Rif chain or the late Miocene deposits; (ii) lagoonal deposits at the base to offshore marls and sands at the top (earliest Pliocene; 5.33–5.04 Ma interval; foraminifer zone PL1); (iii) marine recovery occurring in the 5.32–5.26 Ma interval; and (iv) the change from lagoonal to offshore environments occurring within deposits tens of metres thick. This information indicates that at least the end of the reflooding period was progressive, not catastrophic as previously thought.
ISSN: 0037-0738

hal-01306672
https://hal.archives-ouvertes.fr/hal-01306672
DOI : 10.1016/j.sedgeo.2015.12.014

Éditeur(s) : HAL CCSD
Résumé : International audience
The purpose of our study is to model a geothermal reservoir. When geothermal reservoir are assumed to be composed of pure water, the transfer of mass and energy is classically described by two balance equations: mass balance equation and the energy balance equation. In addition to those equations, fluid velocity ist classically given by the Darcy law while thermodynamic properties, inferred from theoretical or empirical equations of state, are used to close the mathematical system. Once this system is closed, there exist different solutions. The first one is to solve for pressure and temperature with a variable switch to saturation in the two-phase region (e.g. TOUGH2). The second one is to solve for pressure and enthalpy to increase stability of phase transition between single and two-phase states (e.g. Hydrotherm). We adopted the second option and chose te use a splitting method to get rid of the complexity of coupling equations and a finite volume method for the spatial discretization. Selecting object-oriented languages, we developed a multi-language framework, combining Python, Fortran and a C++ implementation of IAPWS (from the freesteam project) including the supercritical equations, in porous media velocity is given by Darcy law and to close the system physical properties are determined by the IAPWS-IF97 thermodynamic formulation. We resolve the equations in pressure and enthalpy instead of pressure and temperature in order to increase stability and to handle easier the passage from a single-phase to a two-phase system. We solve the system by using a splitting method - to get rid of the complexity of coupling equations - and a finite volume method. We offer some freedom to users thanks to the implementation of several methods like explicit or implicit Euler, Runge-Kutta or BDF2 for time solvers or GMRES and BICGSTAB for the linear solver. We can handle several boundary conditions like no-flow - describing a boundary which can not exchange matter with the exterior - or like a mixed-therm condition - a Dirichlet condition to the pressure and a Dirichlet or an outflow condition to the temperature in order to describe a recharge or a discharge zone - ... We're developing a multi-language framework, combining Python, Fortran and the C++ implementation of IAPWS (from the freesteam project). All these languages are object-oriented. We've applied this simulation model to the dogger in Paris, France, to several one-dimensional systems and a two-dimensional one made by Coumou with the CSMP++ platform. The dogger is a reservoir exploited to produce heat by pumping water at 70 and reinjecting it in the reservoir at 40. In the one-dimensional systems we wanted to observe the process of heat transfer from a higher temperature boundary to a smaller one in a high-energy domain. The last simulation shows the natural convection of water in a fault. For every simulation we compared the solutions we found with an other code (TOUGH2 or CSMP++) and they agreed. The next step will be to model the geothermal plant in Guadeloupe, West Indies. It's the only place in France - and in the West Indies so far - producing electricity with the earth power. The temperature can reach up to 1000 and the pressure range is around a few hundreds MPa. In some surface zones we can see two-phase water at atmospheric pressure. In the 1980s Bouillante was a laboratory for France. Since 1995 Bouillante has given 30GWh electricity a year to the Guadeloupeans.
PROCEEDINGS, Thirty-Ninth Workshop on Geothermal Reservoir Engineering
Stanford, United States

Droits : info:eu-repo/semantics/OpenAccess
hal-00944133
https://hal-brgm.archives-ouvertes.fr/hal-00944133
https://hal-brgm.archives-ouvertes.fr/hal-00944133/document
https://hal-brgm.archives-ouvertes.fr/hal-00944133/file/Copol.pdf

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
We report new textural and chemical data for 10 garnet peridotite xenoliths from the Udachnaya kimberlite and examine them together with recent data on another 21 xenoliths from the 80-220 km depth range. The samples are very fresh (LOI near zero), modally homogeneous and large (>100 g). Some coarse-grained peridotites show incipient stages of deformation with <10 % neoblasts at grain boundaries of coarse olivine. Such microstructures can only be recognized in very fresh rocks, because fine-grained interstitial olivine is strongly affected by alteration, and may have been overlooked in previous studies of altered peridotite xenoliths in the Siberian and other cratons. Some of the garnet peridotites are similar in composition to low-opx Udachnaya spinel harzburgites (previously interpreted as pristine melt extraction residues), but the majority show post-melting enrichments in Fe and Ti. The least metasomatized coarse peridotites were formed by 30-38 % of polybaric fractional melting between 7 and 4 GPa and ≤1-3 GPa. Our data together with experimental results suggest that garnet in these rocks, as well as in some other cratonic peridotites elsewhere, may be a residual mineral, which has survived partial melting together with olivine and opx. Many coarse and all deformed garnet peridotites from Udachnaya underwent modal metasomatism through interaction of the melting residues with Fe-, Al-, Si-, Ti-, REE-rich melts, which precipitated cpx, less commonly additional garnet. The xenoliths define a complex geotherm probably affected by thermal perturbations shortly before the intrusion of the host kimberlite magmas. The deformation in the lower lithosphere may be linked to metasomatism.
ISSN: 0010-7999

hal-00941252
https://hal.archives-ouvertes.fr/hal-00941252
DOI : 10.1007/s00410-013-0855-8

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Spinel (± plagioclase) peridotite xenoliths from the Tallante and Los Perez volcanic centres in the eastern Betics (SE Spain) range from depleted (clinopyroxene-poor) harzburgites to fertile (clinopyroxene-rich) lherzolites and orthopyroxene-free wehrlites. Significantly, only one harzburgite, which is depleted in heavy rare earth elements (HREE), retains the imprint of ca. 20% ancient melting of an original garnet lherzolite source. In contrast, REE abundances of other harzburgites and lherzolites from the eastern Betics have been increased by melt-rock reaction. The whole-rock and mineral compositions of these mantle rocks are largely controlled by three types of modal metasomatism: 1) common clinopyroxene-orthopyroxene addition and olivine consumption which increased FeOt, SiO2 and Al2O3, and decreased MgO compared to the refractory melting products; 2) subordinate orthopyroxene dissolution and precipitation of clinopyroxene and olivine, which led to higher FeOt and MgO and lower SiO2 than in common (orthopyroxene-rich) lherzolites; and 3) rare orthopyroxene consumption and olivine addition that caused higher FeOt and lower SiO2 compared to the original melting residues. These mineral modal and major element variations have been produced mostly by interactions with relatively FeOt-rich/SiO2-poor melts, likely derived from a peridotite-pyroxenite lithospheric mantle with a highly heterogeneous isotopic composition. Melting of the lithospheric mantle in the western Mediterranean was triggered by upwelling of the asthenosphere induced by back-arc extension in the Late Oligocene-Early Miocene. Trapping of small fractions of exotic melts in whole-rocks — likely the parental magmas of Miocene back-arc dykes that intruded the Betic crust — caused local disequilibrium between the trace element signatures and Pb isotopic compositions of clinopyroxene and whole-rock. Subsequent interaction with SiO2-undersaturated magmas, similar to the parental melts of the Pliocene alkali basalts that host the xenoliths, promoted orthopyroxene consumption and clinopyroxene-olivine enrichment at locations close to magma conduits, and finally generated orthopyroxene-free wehrlites. This event constitutes the last episode of the Cenozoic magmatic evolution of the westernmost Mediterranean which is recorded in the mantle xenoliths from the eastern Betics.
ISSN: 0024-4937

hal-01553092
https://hal.archives-ouvertes.fr/hal-01553092
DOI : 10.1016/j.lithos.2016.12.011

Éditeur(s) : HAL CCSD
Résumé : International audience
The aim was to identify patterns of work organization characteristics using data from epidemiological surveillance program of musculoskeletal disorders (MSD) implemented in the Pays de la Loire region between 2002 and 2005. A total of 3710 workers were included and completed a administered questionnaire including 16 organizational variables. Ascendant hierarchical clustering (AHC) of organizational variables and AHC of workers had identified five patterns of work organization characteristics: technical constraints and weak decision latitude; internal/external demand and mean decision latitude; weak pace constraints and mean decision latitude; internal/external demand and high decision latitude; weak pace constraints and high decision latitude. Relationships with MSD diagnosed by occupational physicians were then studied.
The specific health programs (SHP) are one of the four mechanisms of prevention planned by the Health and Safety at work Law in the province of Quebec. If the Law appoints only a responsible doctor, it is in reality Health at work teams (HWT) that develop these SHP. In this communication, based on the model of the working situation and the diagram of inter professional practices of collaboration, we study the practices of inter professional collaboration (CIP) in the HWT. The observed practices vary between independent practices, in parallel, of consultation, of dialogue and in shared services. Formalization of the teams, coordination of communication, leadership, respect and professional identities influence particularly the practices of CIP.
L’objectif était d’identifier des patterns de caractéristiques d'organisation du travail à partir des données du programme de surveillance épidémiologique des troubles musculo-squelettiques (TMS) mis en œuvre dans les Pays de la Loire entre 2002 et 2005. Au total, 3 710 salariés ont été inclus et ont répondu à un questionnaire comportant notamment 16 variables organisationnelles. Une classification ascendante hiérarchique (CAH) des variables organisationnelles puis une CAH des salariés ont permis d’identifier cinq patterns de caractéristiques d’organisation du travail : contraintes techniques et faible latitude décisionnelle ; demande interne/externe et latitude décisionnelle moyenne ; faibles contraintes de rythme et latitude décisionnelle moyenne ; demande externe/interne et forte latitude décisionnelle ; faibles contraintes de rythme et forte latitude décisionnelle. Les associations avec les TMS diagnostiqués par des médecins du travail ont ensuite été étudiées.
Actes du 50ème congrès de la Société d'Ergonomie de Langue Française
Paris, France

halshs-01307785
https://halshs.archives-ouvertes.fr/halshs-01307785

Éditeur(s) : HAL CCSD
Résumé : One of the major challenges in forest ecology is to understand the ecology, physiology and potential responses of the> 250000 species of vascular plants of the planet through the categorization of this diversity into functional groups. This approach is essentially based on functional traits analysis, but few investigations were made in tropical areas. The aim of this study was to determine functional groups in two contrasted tropical ecosystems, dry (DF) and mountain rain (MRF) forest (respectively rainfall of 1 200 mm/year and 10 000 mm/year). Guadeloupe Island in FWI presents both these ecosystems spread over less 100 km. In a first time, we developed an original species typology based on 7 "soft" traits, easy to measure (stomatal density, leaf trichom density, chlorophyll content, leaf nitrogen content, specific leaf area, wood density, leaf area, plant height). The method was based on principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) applied to these traits measured at the individual level (Blazy et al., 2009). In a second time, we evaluated the relevance of these soft trait-based groups compared to a typology based on 5 "hard" ecophysiological traits, more costly to quantify but with higher functional significance (difference between predawn and minimum leaf water potential, stomatal conductance, maximal carbon assimilation rate, leaf water potential at 90% of loss of stem hydraulic conductivity). When performed on the dominant canopy species in DF and MRF (a total of 13 species and 60 mature individuals), the typological approach based on soft traits seems relevant to discriminate groups with a distinct functional reality. Through both ecosystems, we obtained 4 homogenous groups. Two were exclusively composed by DF's or MRF's species, indicating that a functional strategy can be linked to specific environmental conditions. The two other groups showed a mix of DF and MRF species indicating that different functional strategies can coexist in the same environment. These mixed groups seem distinct by their ecophysiological features, particularly in term of hydraulic characteristics. One group was composed by drought tolerant species, water spender species, with a high xylem embolism resistance, whereas the second one was composed by water saver species, less resistant to embolism. Therefore, a determination of functional groups based on soft traits could be useful to model ecosystem's responses to environmental changes on a global scale.
Book of Abstracts - isem 2013 - Ecological Modelling for Ecosystem Sustainability
Toulouse, France

hal-00964668
https://hal.archives-ouvertes.fr/hal-00964668

Éditeur(s) : HAL CCSD Geological Society of London
Résumé : International audience
The mylonitic Cambrian quartzites, Moine Thrust Zone, NW Scotland, have long been used to study microstructural and petrofabric evolution and to develop understanding of grain-scale processes accommodating large-scale displacements. Today, structural geology is entering a new age of understanding of the basic processes involved in microstructural evolution due to the emergence of novel instrumental techniques and theoretical models. It seems apposite therefore to re-evaluate the microstructure of one example of this classic quartz mylonite from the Stack of Glencoul, Assynt, using arguably the most important of these new techniques, electron backscattered diffraction (EBSD). The three-dimensional (3D) microstructure and petrofabric of this rock was analysed using EBSD, to: 1) corroborate previous optical and X-ray texture goniometry measurements; 2) investigate the potential for sampling and/or tectonic sectioning bias that may be introduced inadvertently into any petrofabric analysis; and 3) predict its seismic properties. It is found that microstructures do differ between orthogonal structural sections, leading to variations in strengths of different components in the overall petrofabric that might impact on seismic properties. The results emphasize the true 3D nature of microstructures and petrofabrics, which can be recognized and accommodated more readily by this new generation of analytical techniques.
Continental Tectonics and Mountain Building: The Legacy of Peach and Horne

hal-00565749
https://hal.archives-ouvertes.fr/hal-00565749

Résumé : Le monde, depuis des millénaires, est bâti sur les fondations de sociétés bilingues. Or, ce « parler multiple » semble depuis toujours être source de conflit. Loin d’être considéré comme une richesse, le bilinguisme (ou plurilinguisme) semble plutôt représenter un problème auquel on tâcherait de trouver une solution. « La multiplicité » dit Louis-Jean Calvet (1999), « est chose mauvaise, on lui préfère de façon toute jacobine un bon gros Etat monolingue bien cerné dans ses frontières politiques et linguistiques ».La région caraïbe occupe une place tout à fait intéressante sur cette scène en perpétuel mouvement qu’est la mondialisation. Ces pays/îles doivent continuellement chercher l’équilibre entre appartenance locale, régionale et internationale, grand nombre d’entre eux luttant toujours aujourd’hui pour concilier leur statut d’anciennes colonies et le rythme rapide de la mondialisation. Cette thèse porte sur la place des langues vivantes dans les écoles du premier degré à la Martinique et à la Dominique et sur les enjeux d’un enseignement bilingue pour ces deux îles qui appartiennent à la fois à la Caraïbe et au monde. Nous proposons, dans un premier temps, une étude de la situation actuelle de l’enseignement des langues dans les deux îles : quelles sont les politiques linguistiques dans les deux contextes? Dans quelle mesure sont-elles mises en œuvre? L’enseignement des langues répond-il aux exigences des textes officiels ? Les politiques linguistiques sont-elles adaptées aux réalités sociolinguistiques de ces îles ? Dans un deuxième temps, nous interrogeons la possibilité d’un enseignement bilingue dès l’école préélémentaire dans les îles de la Martinique et de la Dominique et nous expérimentons des approches d’enseignement des langues en milieu institutionnel et en contexte périscolaire. Nous nous interrogeons sur des modes de fonctionnement différents : ne pourrait-on pas imaginer d’autres manières de faire ? Que pouvons-nous proposer comme solutions complémentaires et/ou alternatives à l’existant ?Enfin, dans un troisième temps, dans une perspective plus globale, nous posons la question de l’éducation bilingue, par une approche comparée, en analysant les faits éducatifs dans deux systèmes différents et en nous intéressant à la question de l’altérité. La compréhension de l’Autre peut-elle améliorer l’existant dans le cas de la Martinique et de la Dominique ? Nous revenons ainsi à la question de l’intérêt et des enjeux d’une comparaison de l’enseignement des langues dans ces deux systèmes, en prenant en compte les identités locales, régionales et internationales à travers des analyses historiques et sociolinguistiques. A la suite de cette analyse, nous faisons des propositions concrètes en faveur d’un enseignement bilingue intégré dans ces deux îles. Ces propositions concernent les domaines tels que la didactique, la planification en éducation et le curriculum bilingue, la formation des enseignants et la politique linguistique de la Caraïbe. Notre question centrale est la suivante : comment enseigner aujourd’hui pour mieux préparer les citoyens caribéens au monde de demain ?
The Caribbean region occupies an interesting space in the perpetually changing scene of globalisation. Caribbean countries or islands must continually seek to balance their sense of belonging to a local, regional and international community. This is sometimes a difficult task as any of them are still fighting to balance their evolution as old colonies with the fast pace of globalisation in a new world.This thesis focuses on language teaching at primary level in the islands of Martinique and Dominica. It examines the many issues surrounding language teaching and questions the role of bilingual education in the development of these two Caribbean islands as they evolve within the Caribbean and the world. Firstly, we propose a careful study of the current situation of language teaching in Martinique and Dominica. What are the language policies of these islands? How and to what extent are they implemented? Does language teaching truly reflect the objectives of official texts? Are the present language policies adapted to the sociolinguistic reality of each island?Secondly, we raise the question as to the possibility of the implementation of bilingual education at the pre-primary level in the islands of Martinique and Dominica. We examine the question through the experimenting of different language teaching methods within a school setting and as part of an extracurricular bilingual program. Can we envision alternative approaches to the present situation? What complementary or alternative solutions can we propose to improve on what already exists?Lastly, we look at the subject from an overall perspective and we address the question of bilingual education. We analyse how comparative education, the study of other education systems and the understanding of others play a major role in developing solutions to present day situations. This analysis takes into account issues relating to local, regional and international identities through a study of the historical and sociolinguistic context of the islands of Dominica and Martinique.Based on our analysis and on the literature, we put forward concrete proposals for holistic bilingual education on the islands of Martinique and Dominica. These proposals focus on areas such as language teaching pedagogy, education planning, the bilingual curriculum, teacher training, and language policy for the Caribbean. The main question underlying this thesis is: how do we teach today to better prepare Caribbean citizens for the world of tomorrow?

http://www.theses.fr/2015AGUY0834/document

Éditeur(s) : HAL CCSD
Résumé : International audience
In Martinique various early cedrosan saladoïd sites have been excavated extensively. This works have produced an exceptional ceramic collection. In other hand, an important 14C datation program of the early cedrosan saladoïd sites has been develop during the last years. By this way it have been possible to realize an new early saladoïd ceramic production typology based on the analysis of 312 archaeological complete pieces. More than descriptive the goal of that typology is to be useful for a functional analysis of that type of artifacts.
En Martinique plusieurs sites saladoïdes cédrosans anciens ont fait l'objet de fouilles extensives. Ces travaux ont permis de recueillir une série céramique exceptionnelle. Par ailleurs, un important programme de datation des premières occupations agricoles de l'île a été mené à bien ces dernières années. Il nous a donc été possible de développer une typologie originale de la production céramique saladoïde cedrosane ancienne sur la base de l'analyse de 312 formes archéologiquement complètes. Au-delà de son caractère descriptif cette typologie est destinée à servir de support à une analyse fonctionnelle de cette production.
Actes du XXéme congrès de l'Association Internationale d'Archéologie de la Caraïbe, République Dominicaine, Santo Domingo, Juillet 2003
Santo Domingo, Dominican Republic

hal-00965998
https://hal.univ-antilles.fr/hal-00965998
https://hal.univ-antilles.fr/hal-00965998/document
https://hal.univ-antilles.fr/hal-00965998/file/Typologie_de_la_cA_ramique_saladoA_de_cedrosance_ancienne.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Several recent studies have documented that reactions between melt and crystal mush in primitive gabbroic rocks (via reactive porous flow) have an important control in the formation of the lower oceanic crust and the evolution of MORBs. In this context, olivine-rich rocks can form either by fractional crystallization of primitive melts or by open system reactive percolation of pre-existing (possibly mantle-derived) olivine matrix. To address this question, we performed in-situ trace element analyses (by LA-ICP-MS) of olivine from the Erro-Tobbio ophiolite Unit (Ligurian Alps), where mantle peridotites show gradational contacts with an hectometer-scale body of troctolites and plagioclase wehrlites, and both are cut by later decameter-wide lenses and dykes of olivine gabbros. Previous studies inferred that troctolites and olivine gabbros represent variably differentiated crystallization products from primitive MORB-type melts. Olivines in the three rock types (mantle peridotites, troctolites, olivine gabbros) exhibit distinct geochemical signature and well-defined elemental correlations. As expected, compatible elements (e.g. Ni) show the highest concentrations in peridotites (2580–2730 ppm), intermediate in troctolites (2050–2230 ppm) and lowest in gabbros (1355–1420 ppm), whereas moderate incompatible elements (e.g. Mn, Zn) show the opposite behaviour. By contrast, highly incompatible elements like Zr, Hf, Ti, HREE are variably enriched in olivines of troctolites, and the enrichment in absolute concentrations is coupled to development of significant HFSE/REE fractionation (ZrN/NdN up to 80). AFC modelling shows that such large ZrN/NdN ratios in olivines are consistent with a process of olivine assimilation and plagioclase crystallization at decreasing melt mass, in agreement with textural observations. In-situ trace element geochemistry of olivine, combined with microstructural investigations, thus appears a powerful tool to investigate reactive percolation and the origin of olivine-rich rocks in the lower oceanic crust.
ISSN: 0016-7037

hal-01419938
https://hal.archives-ouvertes.fr/hal-01419938
DOI : 10.1016/j.gca.2016.06.029

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
During ODP Leg 209, a magma-starved area of the Mid-Atlantic Ridge (MAR) was drilled in the vicinity of the Fifteen-Twenty Fracture Zone (FZ) that offsets one of the slowest portions of the spreading ridge. We present here the results of a bulk rock multi-elemental study of 27 peridotites drilled at Sites 1272 and 1274 (to the south and the north of the FZ, respectively). The peridotites comprise mainly of harzburgites with minor dunites. Clinopyroxene (Cpx), which is interstitial and interpreted as secondary, is observed in Site 1274 peridotites. Sites 1272 and 1274 peridotites have low Al2O3 contents (<= 1 anhydrous wt.%), high Mg# (>91.5), and bulk rock trace elements compositions mostly below 0.1 x primitive mantle (PM). These peridotites, and in particular Site 1272 peridotites, represent the most depleted peridotites yet sampled at a slow spreading ridge. Their compositions indicate high degrees of partial melting and melt extraction. A single open-system melting event (melting plus percolation of melts produced within upwelling mantle) can explain their highly depleted yet linear chondrite-normalized REE patterns, characterized by a steady depletion from HREE to LREE. Late melt-rock reactions and precipitation of Cpx explains the slightly less depleted compositions of Site 1274 peridotites. Hence, the differences in composition between Sites 1272 and 1274 peridotites do not provide evidence for regional variations in the degrees of partial melting from the south to the north of the FZ. The occurrence of highly refractory peridotites in the Fifteen-Twenty area suggests we sampled a more actively convecting mantle than generally supposed below slow spreading centers.
ISSN: 0012-821X

hal-00412001
https://hal.archives-ouvertes.fr/hal-00412001
DOI : 10.1016/j.epsl.2007.11.058

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : The Costa Maya is a vernacular coastal region of southeastern Quintana Roo (Mexico) and adjacent Ambergris Cay, Belize. As Mexico’s Caribbean coast suffered many growth pains associated with mass tourism development in Cancun and along the Riviera Maya, the Costa Maya by contrast was projected for more sustainable development including low-density housing and ecotourism. Development so far has been concentrated in Puerto Costa Maya, where a cruise ship pier and terminal were built in 2001. The nearby beach resort (balneario) of Majahual became dependent upon the 10-12 shiploads of tourists that descended upon it every week. In spite of big development plans, the more remote beaches of the Costa Maya cater to fewer, but well-heeled ecotourists and dive tourists. Hurricane Dean made landfall in August 2007 as a category-5 storm, and economic recovery only began in late 2008 when the cruise ship pier re-opened and Majahual rebuilt. As of late 2009, the cruise-ship traffic had still not recovered to pre-Dean levels, and a global recession coupled with swine-flu and drug violence scares has lowered U.S. tourism to Mexico. To what degree new tourism infrastructure such as an international airport at Tulum, a proposed causeway from Chetumal to the beach, and a new resort complex at Xahuayxel will stimulate tourism on the Mexican Costa Maya and eventually lead to a coastal highway link with San Pedro, Belize is still unknown.
La Costa Maya est une région côtière du sud du Quintana Roo (Mexique), proche de l'îlet Ambergris au Bélize. Contrairement à la côte caribéenne du Mexique qui a souffert du développement du tourisme de masse à Cancun et le long de la Riviera Maya, la Costa Maya s'est orientée vers un développement durable avec notamment une faible densité de construction et le développement de l'écotourisme.Le développement s'est concentré autour de Puerto Costa Maya où un terminal de croisière a été construit en 2001. La station balnéaire (balneario) de Majahual est devenue dépendante des 10-12 bateaux de touristes qui débarquaient chaque semaine. En dépit d'importants plans de développement, les plages reculées de la Costa Maya accueillaient tout au plus des écotouristes aisés et du tourisme lié à la plongée sous-marine.Le cyclone Dean, de catégorie 5, a dévasté le paysage en août 2007 et le rétablissement économique n'a pu être entamé que fin 2008, après la réouverture du terminal de croisière et la reconstruction de Majahual. Fin 2009, le trafic de croisière n'a pas retrouvé son niveau d'avant Dean et la récession mondiale couplée avec la grippe porcine et les violences liées à la drogue ont fait diminuer le tourisme en provenance des Etats-Unis. On ignore à quel niveau les nouvelles infrastructures tels l'aéroport international de Tulum qui propose un itinéraire de Chetumal à la plage et le nouveau complexe hôtelier à Xahuayxel, stimuleront la Costa Maya mexicaine créant peut-être une autoroute côtière reliée à San Pedro au Bélize.
Cancún
Costa Maya
Mexique

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.3867
http://journals.openedition.org/etudescaribeennes/3867

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : En développant, à partir de 1984, un Centre touristique Intégralement Planifié dans une localité de la côte Pacifique de l’état d’Oaxaca, l’État mexicain entendait impulser un développement économique dans une région périphérique et pauvre du pays. Basé sur l’expropriation d’une portion du territoire communal, le processus engendre un certain nombre de résistances au sein des communautés locales. Le centre touristique est aujourd’hui un espace fragmenté, reflet et conséquence des inégalités sociales et des conflits sociaux. Depuis une perspective de géographie sociale, cet article cherche à mettre en lumière les conflits et compromis sociaux qui traversent la société locale. L’appropriation de l’espace, les luttes de pouvoir et les stratégies développées par les différents acteurs seront les entrées privilégiées pour interroger un modèle de planification, « par le haut », ignorant trop souvent les réalités sociales à l’échelle locale.
Since 1984, the Mexican government has tried to stimulate the economy in a poor and peripheral area of the country. They aimed to do so by developing an Integrally Planed Resort (CIP, in Spanish) in a community, located in the Oaxaca state on the Pacific coast. Being based on the expropriation of some parts of the communal territory, this process created some remittances among the local communities. Today, this resort is still a fragmented space and reflects social inequalities and social conflicts. From a social geographical perspective, this article aims to show the social conflicts and social compromises among the local society. Space appropriation, power battles and strategies developed by the different actors, will be the main tools to investigate this planning model. In this model, the government too often has ignored social realities on the local scale.
Al crear, a partir de 1984, un Centro turístico Integralmente Planeado en un poblado de la costa del estado de Oaxaca, el gobierno mexicano pretendió impulsar el desarrollo económico de una región periférica y marginada del país. Basado en la expropiación de una parte del territorio municipal, dicho proceso genera resistencias entre las comunidades locales. Hoy en día, el centro turístico es un espacio fragmentado, reflejo y consecuencia de las desigualdades sociales y conflictos. Desde una perspectiva de geografía social, el presente artículo buscará destacar los conflictos y compromisos sociales que atraviesan la sociedad local. La apropiación del espacio, las luchas de poder y las estrategias desarrolladas por los diferentes actores serán los enfoques privilegiados para cuestionar un modelo de planeación “vertical”, que suele ignorar las realidades sociales a nivel local.
Mexique

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.4069
http://journals.openedition.org/etudescaribeennes/4069

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Oman ophiolite includes both a fossil fast spreading axis, defined by five mantle diapirs, and an off-axis mantle diapir emplaced 30 km from the axis, providing a natural laboratory for the study of off-axis magmatic processes. We compare field and petrological observations coupled with geochemical and isotopic analyses of samples from the off-axis diapir with those of the nearest on-axis diapir, with a particular focus on the Moho Transition Zone (MTZ). Both diapirs are defined by the presence of steeply plunging lineations, but in the on-axis case, these lineations rotate gradually into parallelism with the horizontal magmatic lineations of the overlying crust, while in the off-axis case, a shear zone separates the steeply plunging lineations from the horizontal lineations of the surrounding mantle. In the on-axis diapir, the MTZ is 50 to 500 m thick and composed of dunite with layered gabbro lenses whereas in the off-axis diapir, the MTZ is thicker and composed of dunite with massive (∼20% of MTZ) clinopyroxenite lenses and a notable absence of plagioclase. Moreover, the off-axis diapir is associated with amphibole-bearing intrusions, consisting of Mg-rich gabbroic sills in the mantle peripheral to the diapir, and microgabbroic lenses of broadly basaltic composition in the overlying crust. The ε Nd values of the pyroxenites in the MTZ of the off-axis diapir fully overlap with those of the intrusions in the surrounding mantle and crust, suggesting that they are genetically related. Calculated rare earth element (REE) abundances of liquids in equilibrium with clinopyroxene imply that the magmas that traversed the MTZ of the off-axis diapir were more depleted in highly incompatible elements than their counterparts in the MTZ of the on-axis diapir. On the other hand, Nd isotopic compositions of the off-axis samples (εNd=6.2–7.9εNd=6.2–7.9 in 18 of 19 samples) indicate derivation of their parental magmas from a less depleted source than that which produced the magma associated with the on-axis gabbro (εNd=7.8–9.2εNd=7.8–9.2, 10 analyses).To explain these observations, we suggest that the earliest magmas in the uprising off-axis diapir formed from the partial melting of pyroxenite veins with less radiogenic Nd isotopic compositions than those of the ambient peridotite. As the diapir traversed the cool, hydrated lithosphere these early melts interacted with depleted harzburgites, lowering the incompatible element contents of the melt products while having little effect on their Nd isotopic compositions. The great abundance of clinopyroxene in the off-axis MTZ might be explained by the high pyroxene component in the original melt but perhaps also by the presence of water in the lithosphere, which would favor the crystallization of clinopyroxene while inhibiting that of plagioclase. The intrusions in the overlying crust could represent, to first order, the secondary melts produced by the melt–harzburgite reaction, while the sills in the surrounding mantle may be cumulates from such secondary melts.These results shed light on processes occurring during interaction between rising off-axis material and depleted, hydrated lithospheric mantle. Furthermore, if our interpretation is correct, the low εNd values of the off-axis samples contribute to the growing body of evidence for the presence of pyroxenite veins in the MORB mantle source.
ISSN: 0012-821X

hal-01306575
https://hal.archives-ouvertes.fr/hal-01306575
DOI : 10.1016/j.epsl.2015.12.005

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Cette étude démontre que l’écriture du roman The Swinging Bridge constitue une action de récupération de la mémoire féminine indienne qui réactive les liens entre Indo-Trinidadiens du Canada et Indo-Trinidadiens vivant à Trinidad tout en rétablissant une relation avec l’Inde des origines. Elle montre que, dans l’espace du roman, des relations s’établissent entre le centre historique réel ou mythique des établissements dispersés, et des sociétés d’installation par le biais d’une intrigue qui amène personnages et lecteurs à la conscience de former un peuple en diaspora.Elle analyse les procédés littéraires d’une récupération de la mémoire qui révèle, rectifie et réorganise dans une nouvelle cohérence des fragments épars réintroduisant dans la mémoire collective les qualités ancestrales d’indépendance de la femme indienne. Elle révèle le caractère hybride de l’identité culturelle diasporique qui se construit tout au long du roman puis analyse les enjeux pour l’écrivain féminin postcolonial diasporique de cet acte de représentation.Elle conclut que cette représentation constitue une réécriture contre discursive de l’Histoire trinidadienne et qu’elle introduit la définition d’un continuum identitaire indo-américain qui contribue à résorber la dislocation et la fragmentation qui caractérisent cet espace essentiellement diasporique.
This work proposes to read The Swinging Bridge as a process by which a hybrid Indo-Trinidadian Diaspora is created. It argues that the novel’s recovery of memory constitutes a process by which individual memories turn into a collective diasporic memory which re-establishes links between Indo-Trinidadians dispersed in Canada and Trinidad. We demonstrate that rebinding to the Trinidadian space and recovering part of the memory of the Indian historical centre set the three spaces in a diasporic relation.This study also demonstrates that the novel’s narrative semantics rejects cultural conflict, as well as essentialism and creates a hybrid cultural identity. It establishes that the construction of diaspora at work in The Swinging Bridge advocates for the appreciation routes rather than roots and is compatible with the idea of a multi-locational diasporic consciousness.
Caraïbes
Trinité

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5757
http://journals.openedition.org/etudescaribeennes/5757

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We carried out detailed petrographic, major and trace element geochemical, microstructural and FTIR analyses on eight characteristic ultramafic xenoliths from Nyos and Barombi Mbo Lakes in the continental sector of the Cameroon Volcanic Line (CVL). The studied xenoliths are spinel lherzolites showing lithologies similar to the other xenoliths reported previously along the CVL. They have protogranular and porphyroclastic textures. One of the Barombi xenolith contains amphibole, which had not been previously reported in this locality. Amphibole is common in the Nyos xenoliths suite. Peridotite xenoliths from both localities show some chemical heterogeneity, but Barombi xenoliths generally are less depleted in basaltic elements with respect to Nyos xenoliths. Trace element compositions of Nyos spinel lherzolites show a moderately depleted initial (premetasomatic) composition and variable enrichment in REE. Evidence for both modal and cryptic metasomatism is present in Nyos xenoliths. Rare earth element patterns of clinopyroxene suggest that interaction between mafic melts and the upper mantle occurred beneath the Nyos locality. Barombi Mbo xenoliths, on the other hand, record a small degree of partial melting. The Barombi Mbo xenoliths have weak, dominantly orthorhombic olivine crystal preferred orientations, whereas Nyos ones have strong axial-[010] patterns, which may have formed in response to transpression. Nominally anhydrous mantle minerals (NAMs) of the Barombi Mbo xenoliths show generally higher bulk concentrations of ‘water’ (70–127 ppm) than Nyos xenoliths (32–81 ppm). The Barombi Mbo xenoliths could originate from a juvenile segment of the lithospheric mantle, which had been originally part of the asthenosphere. It became a part of the lithosphere in response to thermal relaxation following the extension, forming a weakly deformed lower lithospheric mantle region along the CVL. The Nyos xenoliths, however, represent a shallow lithospheric mantle bearing imprints of several depletion and enrichment events probably prior or following the extension (at ∼30 Ma).
ISSN: 0899-5362

hal-01236039
https://hal.archives-ouvertes.fr/hal-01236039
DOI : 10.1016/j.jafrearsci.2015.07.006

Éditeur(s) : HAL CCSD Wiley
Résumé : Clay shale landscapes are sensitive to landslide, erosion, and re-sedimentation processes. In this context, tectonized clay shales have peculiar hydrological and mechanical behaviours. In order to improve our understanding of the processes involved in such systems, an experimental site has been settled in the Draix Observatory (ORE DRAIX) on a black marl hill slope of the Southern Alps (France) in the framework of the ECOU-PREF project. The site is a natural laboratory to study the evolution of clay shale landscapes at several scales (regional to µm). In this study, we aim to characterize the internal structure and fissure patterns of a stable interfluve, in order to locate preferential water flows within the system, and anticipate its evolution. This work is based on a series of mutli-disciplinary approaches including petrophysical analyses, well pulse injection tests and downhole geophysical measurements. Borehole geophysical results were combined with laboratory measurements on core plugs (permeability, density, porosity, and acoustic velocity). Optical and acoustical images have been used as an original tool for internal discontinuities characterisation and potential active flow path detection. They allowed the identification of three main lithological units interpreted as several stages of shale alteration. In addition, several main structural plane discontinuities (open fractures, schistosity planes, and fractures infilled with calcite or clays) were identified from the images and their potential transmissivity discussed with regard to piezometric and tracer measurements. In all, the integration of measurements leads to propose a simple scenario of fluid circulation and chemical alteration of the interfluve.
ISSN: 0885-6087

hal-00757581
https://hal.archives-ouvertes.fr/hal-00757581
DOI : 10.1002/hyp.7997