Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
AimEcological connectivity is currently considered to be essential to enhance biodiversity conservation efforts and benefit adjacent areas. We evaluate the spatial structure of vulnerable marine benthic invertebrate populations based on connectivity to improve the placement of marine protected areas.LocationGulf of Lions, NW Mediterranean Sea.MethodsWe used a spatially explicit metapopulation model to explore how larval dispersal affects marine benthic invertebrate dynamics at local and regional scales. Minimum recruitment success (the proportion of larvae that settle in a site and survive between spawning and first reproduction, which is required to ensure species persistence) is proposed as a measure of vulnerability. Three contrasting simulations were constructed: closed versus connected populations, habitat loss versus recruitment failure disturbances and varying patterns of oceanographic connectivity. The rescue factor (the ratio of minimum recruitment success in connected and closed populations) quantified the decrease in vulnerability because of oceanographic connectivity.ResultsIn the Gulf of Lions, connectivity reduced population vulnerability by a rescue factor of 5.3. The minimum recruitment success for regional persistence decreased from 3% to 0.2% when species' life expectancies increased from 2 to 50 years. Connectivity enabled the spread of individuals over the entire region, but there were higher densities in sink sites, where low retention rates do not allow for local persistence (western tip of the gulf). Source sites, defined as those sites bringing metapopulation resistance to recruitment failure and stresses from habitat loss, were located in the centre of the gulf.Main conclusionsConnectivity drives the spatial structure of population density distribution and population vulnerability in the absence of any other structuring factor. In the Gulf of Lions, marine protected areas are located in population sinks; however; if protection measures were taken in the central part, populations would benefit throughout the region via the rescue effect.
ISSN: 1366-9516

hal-01341743
https://hal-univ-perp.archives-ouvertes.fr/hal-01341743
DOI : 10.1111/ddi.12254

Éditeur(s) : Taylor & Francis Ltd
Résumé : A new method is developed to estimate daily turbulent airsea fluxes over the global ocean on a 0.25 degrees grid. The required surface wind speed (w(10)) and specific air humidity (q(10)) at 10m height are both estimated from remotely sensed measurements. w(10) is obtained from the SeaWinds scatterometer on board the QuikSCAT satellite. A new empirical model relating brightness temperatures (T-b) from the Special Sensor Microwave Imager (SSM/I) and q(10) is developed. It is an extension of the author's previous q(10) model. In addition to T-b, the empirical model includes sea surface temperature (SST) and airsea temperature difference data. The calibration of the new empirical q(10) model utilizes q(10) from the latest version of the National Oceanography Centre airsea interaction gridded data set (NOCS2.0). Compared with mooring data, the new satellite q(10) exhibits better statistical results than previous estimates. For instance, the bias, the root mean square (RMS), and the correlation coefficient values estimated from comparisons between satellite and moorings in the northeast Atlantic and the Mediterranean Sea are 0.04gkg(1), 0.87gkg(1), and 0.95, respectively. The new satellite q(10) is used in combination with the newly reprocessed QuikSCAT V3, the latest version of SST analyses provided by the National Climatic Data Center (NCDC), and 10m air temperature estimated from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses (ERA-Interim), to determine three daily gridded turbulent quantities at 0.25 degrees spatial resolution: surface wind stress, latent heat flux (LHF), and sensible heat flux (SHF). Validation of the resulting fields is performed through a comprehensive comparison with daily, in situ values of LHF and SHF from buoys. In the northeast Atlantic basin, the satellite-derived daily LHF has bias, RMS, and correlation of 5Wm(2), 27Wm(2), and 0.89, respectively. For SHF, the statistical parameters are 2Wm(2), 10Wm(2), and 0.94, respectively. At global scale, the new satellite LHF and SHF are compared to NOCS2.0 daily estimates. Both daily fluxes exhibit similar spatial and seasonal variability. The main departures are found at latitudes south of 40 degrees S, where satellite latent and sensible heat fluxes are generally larger.
International Journal Of Remote Sensing (0143-1161) (Taylor & Francis Ltd), 2013-07 , Vol. 34 , N. 14 , P. 5243-5261

Droits : 2013 Taylor & Francis
http://archimer.ifremer.fr/doc/00137/24825/23575.pdf
DOI:10.1080/01431161.2013.787502
http://archimer.ifremer.fr/doc/00137/24825/

Éditeur(s) : HAL CCSD University of Chicago Press
Résumé : International audience
Contrasting tectonic reconstructions of the westernmost Mediterranean have been proposed to explain the origin of the Alboran marine basin contemporaneously with Cenozoic convergence between the African and European plates. Cr-rich pyroxenites in the Ronda massif record the geochemical processes occurring in the subcontinental mantle of the Alboran domain in the Late Oligocene, thus constraining the geodynamic scenario of Cenozoic extension in the western Mediterranean lithosphere. Clinopyroxene in intrusive Cr-rich websterite dikes crosscutting the Ronda peridotite is strongly depleted in Nb-Ta and enriched in light rare earth elements, as typically observed in arc magmas, and is in trace element equilibrium with Neogene subduction-related lavas from the western and central Mediterranean. Sr-Nd-Pb radiogenic isotopes indicate that the mantle source of the Ronda pyroxenite dikes was contaminated by a subduction component released by detrital sediments likely deposited in passive continental margins. Rather than convective removal or delamination of the lithospheric root, our data strongly support Alboran geodynamic models that envisage slab rollback as the tectonic mechanism responsible for the Miocene lithospheric thinning. The Ronda Cr-rich pyroxenite dikes represent the earliest unambiguous manifestation of subduction-related magmatism in the western Mediterranean and testify to the involvement of terrigenous sediments in the primitive stages of subduction.
ISSN: 0022-1376

hal-00745853
https://hal.archives-ouvertes.fr/hal-00745853
DOI : 10.1086/663875

Éditeur(s) : HAL CCSD Elsevier
Résumé : The Gulf of Aigues-Mortes (NW Mediterranean Sea) is a midshelf zone whose scale is an intermediate between the nearshore scale (0–10 m depth) and the coastal scale (including the whole continental shelf). Its hydrodynamics is investigated for the first time. ADCP, CTD and thermosalinograph data were collected during three short cruises (HYGAM; March 6–7, 20–21, April 5–6, 2005). They were scheduled approximately every 15 days to sample the gulf circulation under different weather conditions. Moreover, the cruise data were used to validate the Symphonie model, a 3D primitive equations circulation model. The circulation features displayed by in situ data were well reproduced by Symphonie. A downscaling modelling approach was implemented, the largest scale being obtained by the replay of the MFSTEP regional model of the North-Western Mediterranean Sea. The analysis, closely coupling in situ measurements and model results, provides information that would not have been obtained using data separately. The great variability of the oceanic circulation at this scale is well evidenced. Winds are the main forces, not only locally but also at a larger scale. North winds generate coherent structures interacting with the general Mediterranean circulation. The explanation of the induced currents is then not straightforward, some of them being, for example, northward. South and southeast winds reinforce the sloping surface, the latter allowing the geostrophic equilibrium with longshore currents. This study, focused on the end of winter 2004–2005, also enhances the heat fluxes from offshore to nearshore, as well as the initiation of shelf dense waters. The knowledge of the midshelf oceanic circulation is then applied to run a numerical experiment which describes both the dispersion of a fictive contaminant from a point S (at the centre of the GAM), and evaluates the risk of contamination of the beaches along the GAM shores.
ISSN: 0278-4343

hal-00196620
https://hal.archives-ouvertes.fr/hal-00196620
DOI : 10.1016/j.csr.2007.06.006

Éditeur(s) : HAL CCSD Elsevier
Résumé : An integrated magneto-biostratigraphic study, based on calcareous nannofossils and foraminifers, together with the radiometric dating of a volcaniclastic layer found in several outcrops, was carried out on the hemipelagic deposits of the Lindos Bay Formation (LBF) at six localities on the island of Rhodes (Greece). Our highly refined chronostratigraphic framework indicates that the lower and upper lithostratigraphic boundaries of the LBF are diachronous. Associated with the 40Ar/39Ar age determination of 1.85 ± 0.08 Ma for the volcaniclastic layer, our data show that among the investigated outcrops, the Lindos Bay type locality section provides the longest record (1.1 Ma) of the LBF. Hemipelagic deposition occurred continuously from the late Gelasian (∼1.9 Ma) to the late Calabrian (∼0.8 Ma), i.e., from Chrons C2n (Olduvai) to C1r.1r (Matuyama) and from nannofossil Zones CNPL7 to CNPL10. This long record, together with the hemipelagic nature of the deposits, make the Lindos Bay type locality section a unique element in the eastern Mediterranean region, allowing future comparisons with other early Quaternary deep-sea sections available in the central and western Mediterranean regions.
ISSN: 0033-5894

hal-01467764
https://hal.archives-ouvertes.fr/hal-01467764
DOI : 10.1016/j.yqres.2016.05.002

Éditeur(s) : HAL CCSD Université des Antilles
Résumé : International audience
The history of international tourism of the last fifty years can be divided into three stages: 1 / decades from 1950 to 1980, characterized by a progressive democratization of tourism supported by an unparalleled economic growth, 2 / the last decade of the twentieth century, euphoria of a tourist who sees the borders open. The end of a bipolar world announcement many hopes naive. The scope of territories open to tourism continues to widen. 3 / The end of the century announces the age of maturity of tourism. After the euphoria, illusions and disillusions of a space tourist world without borders, facts, often dramatic raised awareness tourists to the complexity of a world where wars have never ceased. The global space tourism is articulated around three regional basins: more than 75% of international tourist flows, driven by the rich European cities, North American and Asian, are confined to their regional area of origin. The distribution of tourist flows draws an organization into three distinct basins: in order of importance, 1 / Euro-Mediterranean basin, focusing on the Mediterranean Sea, 2 / Basin East Asia-Pacific, around the shores of the Sea of China, 3 / basin North America-Caribbean, organized around the "American Mediterranean." Space discontinuities increase between peripheries unstable, extensions selective and margins forgotten or excluded. The climate of insecurity that affect certain touristic territories aimed at weakening the outskirts most sensitive and oblige the international space tourist to retract.
L’histoire du tourisme international des cinquante dernières années peut être décomposée en trois temps : 1/ les décennies de 1950 à 1980, caractérisées par une démocratisation progressive du tourisme soutenue par une croissance économique inégalée ; 2/ la dernière décennie du vingtième siècle, celle d’une euphorie touristique qui voit les frontières s’ouvrir. La fin d’un monde bipolaire annonce bien des espoirs naïfs. Le champ des territoires ouverts au tourisme ne cesse de s’élargir. 3/ La fin du siècle annonce l’âge de maturité du tourisme. Après l’euphorie, les illusions et les désillusions d’un espace touristique mondial sans frontières, les faits, souvent dramatiques ont fait prendre conscience aux touristes la complexité d’un monde où les guerres n’ont jamais cessé. L’espace touristique mondial est articulé autour de trois bassins régionaux : plus de 75 % des flux touristiques internationaux, impulsés par les riches métropoles européennes, nord-américaines et asiatiques, se cantonnent à dans leur espace régional d’origine. La distribution des flux touristiques dessine une organisation en trois bassins distincts : par ordre d’importance, 1/ le bassin euro-méditerranéen, centré sur la Mer méditerranée, 2/ le bassin Asie orientale-Pacifique, autour des rivages de la mer de Chine, 3/ le bassin Amérique du Nord — Caraïbes, organisé autour de la « Méditerranée américaine ». Les discontinuités s’affirment entre des périphéries mal stabilisées, des prolongements très sélectifs, des marges oubliées ou exclues. Les climats d’insécurité qui touchent certains territoires touristiques visent à fragiliser des périphéries plus sensibles et contraignent l’espace touristique international à se rétracter.
ISSN: 1779-0980

hal-01624746
https://hal.archives-ouvertes.fr/hal-01624746
DOI : 10.4000/etudescaribeennes.882

Éditeur(s) : Wiley-blackwell
Résumé : In bird species that have a high movement capacity, dispersal may connect subpopulations over vast geographical regions, with important consequences for the design of conservation management strategies. Here we used a molecular approach to infer the patterns and rates of dispersal among eight Mediterranean subpopulations of the endangered Bonelli's Eagle, based on 245 individuals screened at 17 microsatellite loci. There was moderate genetic differentiation between subpopulations sampled in the western (Iberia and Morocco) and eastern (Cyprus) Mediterranean, whereas differentiation among subpopulations in the former region was weak to moderate and followed a pattern of isolation by distance. Within the western Mediterranean, the small, peripheral and ecologically unique population of southwest Portugal had the lowest genetic diversity and the highest differentiation. The remaining subpopulations formed two loose clusters, one including Morocco and southwest and eastern Spain, and the other northeast Portugal and western and central Spain. Few recent migrants were detected, and they originated primarily from adjacent subpopulations. Our findings suggest that western Mediterranean Bonelli's Eagles may have a large-scale metapopulation structure, with subpopulations connected to some extent by distance-dependent dispersal, probably influenced by natal philopatry and the geographical configuration of subpopulations. The combination of marked ecological and genetic divergence suggests that the peripheral subpopulation of southwest Portugal may be regarded as a distinct management unit.
Ibis (0019-1019) (Wiley-blackwell), 2013-07 , Vol. 155 , N. 3 , P. 485-498

Droits : 2013 British Ornithologists’ Union
http://archimer.ifremer.fr/doc/00148/25924/24018.pdf
DOI:10.1111/ibi.12065
http://archimer.ifremer.fr/doc/00148/25924/

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) : Université des Antilles Études caribéennes
Résumé : Les nouvelles logiques spatiales du port de Barcelone. Tourisme de croisière, aménagement et paysage.Dans le cadre de la gestion urbanistique des quais de Barcelone pour augmenter les navettes de croisières, la capitale catalane profite de ses aménités intrinsèques pour devenir le premier port touristique méditerranéen et le quatrième du monde. Grâce à des aménagements conséquents dont les infrastructures sont les pièces maitresses, la cité devient un modèle de par sa capacité à créer une mise en scène et en récit de son front de mer pour produire un imaginaire empreint de modernité et de tradition. Une enquête de terrain permet de revenir sur la scénographie portuaire par l’intermédiaire d’espace public de qualité et l’importance du rôle des quais pour la rêverie et l’échappatoire à la vie quotidienne. Actuellement, transports aériens et parc hôtelier collaborent avec les opérateurs de croisières, la gouvernance urbaine et portuaire profite d’une collaboration publique/privée pour permettre une meilleure intégration des opérations d’aménagements tout en allégeant les coûts. L’enjeu du développement durable en lien avec le transport de touristes devient crucial du fait de l’importance des flux à contrôler.
The new spatial logical of Barcelona‘s port. Cruiser tourism, planning and landscape.As part of the management of urban banks to increase the Barcelona cruise shuttle, the catalan capital advantage of its amenities inherent to become the first Mediterranean tourist port and the fourth in the world. With facilities including substantial infrastructure are the centerpiece, the city became a model for its ability to create a setting and story of its waterfront to produce a sleek, modern fantasy and tradition. A field survey to return to the staging port through public space quality and the importance of platforms for reverie and escape from everyday life. Currently, air transport and hotel facilities are working with cruise operators, urban governance and port enjoys a public / private collaboration to enable better integration of operations of facilities while reducing costs. The challenge of sustainable development in connection with the transportation of tourists is crucial because of the importance of flow control.
Las nuevas lógicas territoriales del puerto de Barcelona. Turismo de crucero, planificación y paisaje.Como parte de la gestión de los bancos urbanos para aumentar el transporte de cruceros de Barcelona, la ventaja de capital catalán de sus servicios inherentes a convertirse en el primer puerto turístico del Mediterráneo y la cuarta en el mundo. Con instalaciones que incluyen una infraestructura sustancial son la pieza central, la ciudad se convirtió en un modelo por su capacidad para crear un entorno y la historia de su línea de costa de producir una fantasía elegante, moderna y tradicional. Un estudio de campo para volver a la puesta en escena a través de puerto de la calidad del espacio público y la importancia de las plataformas de ensueño y escapar de la vida cotidiana. En la actualidad, facilidades de transporte aéreo y el hotel están trabajando con los operadores de cruceros, la gobernanza urbana y el puerto goza de una colaboración pública / privada para permitir una mejor integración de las operaciones de las instalaciones y reducir los costos. El reto del desarrollo sostenible en relación con el transporte de turistas es crucial debido a la importancia del control de flujo.
Barcelone

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5154
http://journals.openedition.org/etudescaribeennes/5154

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The N-S Languedoc volcanic province between the French Massif Central and the Mediterranean Sea is characterized by sporadic scattered low volume (similar to 2 km(3)) and geochemically homogeneous alkali basaltic activity spanning from 161 to 05 Ma The existence of magmatic activity of such a long duration within such a small area (similar to 140 km long and similar to 60 km wide) in spite of the extensive shift to the East of the European plate (about 2500 km during the last 160 Ma) is problematic Trace-element abundances in lavas suggest low degrees of melting (1-5%) in the spinet-garnet transition zone of an enriched Iherzolitic source The lavas display rather large ranges in Sr isotopic ratios (0 70307-0 70436) The Nd-143/Nd-144 ratio variations are smaller (0 51268-0 51300) and these of Pb-206/Pb-204 Pb-208/Pb-204 and Pb-207/Pb-204 are 18 745-19 515 38 53239 228 and 15 567-15 680 respectively The Languedoc lithospheric mantle as sampled by xenoliths is globally similar to the Pyrenees lithosphere The xenoliths show also rather large Sr Nd and Pb isotopic variations (Sr-87/Sr-86 0 70287-0 70578 Nd-143/Nd-144 0 51256-0 51414 Pb-208/Pb-204 37772-39 041 Pb-206/Pb-204 17 901-19 353) except for Pb-207/Pb-204 (15 570-15 620) The Pb-206/Pb-204 and La/Sm ratios are positively correlated both in xenoliths and lavas The increase of the Pb-206/Pb-204 (which could be interpreted as participation of the European Asthenospheric Reservoir EAR) is probably related to volatile-rich (carbonated?) fluid percolation This is corroborated by LILE and HFSE patterns observed in several xenoliths Therefore our data on lavas and xenoliths suggest a lithospheric origin for this long lived magmatism We propose (1) that the role of the asthenosphere in the Languedoc volcanism was restricted to volatile-rich fluid supplying and (2) that the fluid injection within the lithosphere may be related to the arrival of the Central Atlantic Plume head beneath Western Europe about 70 Ma ago In this model the isotopic signature of the oldest lavas (>70 Ma) would be that of the mantle lithosphere inherited from Hercynian processes The signatures of the subsequent lavas would be driven by the metasomatic component stored within the lithosphere and preferentially mobilized during incipient melting This metasomatised lower lithosphere was close to its solidus and small changes in P (or T) triggered incipient melting leading to basaltic volcanism Successive local re adjustments of the lithospheric blocks which accompanied the Meso-Cenozoic evolution of the Thetys Ligurian margin towards the present Mediterranean margin are the probable cause of these changes and so the sporadic volcanic activity in Languedoc is unrelated to deep asthenospheric processes
ISSN: 0024-4937

hal-00558884
https://hal.archives-ouvertes.fr/hal-00558884
DOI : 10.1016/j.lithos.2010.04.009

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We present new Sr-Nd-Pb isotope data of the western Alpujárride metamorphic basement and the pre-Miocene Flysch sediments of the Betic Cordillera (southern Spain). Nd model ages are consistent with an increasing detrital input from the Alborán domain to the Flysch Trough in the western Mediterranean during the late Oligocene. The Alpujárride metamorphic crustal rocks derived from Archean-Paleoproterozoic terranes located along the northern margin of Gondwana in the Neoproterozoic. The heterogeneous isotopic signatures of the Alpujárride units indicate that they have different sedimentary protoliths and underwent contrasted Variscan and pre-Variscan tectono-magmatic evolutions. Melts/fluids derived from the western Alpujárride gneisses contaminated the mantle source of the Ronda high-Mg pyroxenite dykes, implying that the Alpujárride lower crust underthrusted the subcontinental lithospheric mantle of the Alborán domain generating subduction-like magmatism in the late Oligocene. The western Alpujárride upper crust is involved in the Neogene volcanism of the Alborán Sea basin, but only contaminated some LREE-enriched calc-alkaline lavas erupted along the continental margins. On the other hand, tholeiitic lavas in the center of the basin show no isotopic evidence of crustal assimilation. This indicates that most of the crust in the central Alborán Sea accreted by Miocene tholeiitic magmatism and that Alpujárride lower crust is absent and likely foundered close to the continental margins of the basin.
ISSN: 0024-4937

hal-01526912
https://hal.archives-ouvertes.fr/hal-01526912
DOI : 10.1016/j.lithos.2016.10.003

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 Elsevier
Résumé : International audience
Understanding long-term variability in the frequency of intense storm activity is important for assessing whether changes are controlled by climate evolution. Understanding this variability is also important for predicting present and future community vulnerability and economic loss. Our ability to make these assessments has been limited by the short (less than 50 years) instrument record of storm activity. Storm-induced deposits preserved in the sediments of coastal lagoons offer the opportunity to study the links between climatic conditions and storm activity on longer timescales. In this study, we present a record of these extreme climatic events that have occurred in the French Mediterrannean coast over the past 1500 years. The identification of these extreme events is based on the analysis of sediment cores from Gulf of Aigues-Mortes lagoons that contain a specific sedimentary and geochemical signature associated with intense storms.;Overwash deposits do not show any evidence of intense storm landfalls in the region for several hundred years prior to the late 17th century A.D. The apparent increase in intense storms around 250 years ago occurs during the latter half of the Little Ice Age, a time of lower continental surface temperatures. Comparison of the sediment record with palaeoclimate records indicates that this variability was probably modulated by atmospheric dynamics. The apparent increase of the superstorm activity during the latter half of the Little Ice Age was probably due to the thermal gradient increase leading to enhanced lower tropospheric baroclinicity over a large Central Atlantic/European domain and leading to a modification of the occurrence of extreme wind events along the French Mediterranean coast. A complete understanding of the relationship between climate fluctuations, storm activity, and the coastal response will be crucial to predicting the impacts of future climate change.
ISSN: 0031-0182

hal-00617525
https://hal.archives-ouvertes.fr/hal-00617525
DOI : 10.1016/j.palaeo.2010.11.009

Éditeur(s) : HAL CCSD
Résumé : il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : ACTIVITY_REPORT
Understanding genomic evolution in wild populations is of particular importance because evolution is a central process in our understanding of populations’ history and their future response to global changes. In addition to fundamental knowledge, the study of populations’ evolution has wide applications such as conservation/restoration genetics or epidemiology. Indeed, genetic diversity is the ‘fuel’ for populations’ evolution and adaptation to new conditions, and estimating the extent and the geographic structure of genetic diversity, as well as identifying the evolutionary forces behind (demography, gene flow, and adaptation) are thus major challenges in the current context of global changes. [br/]A particular attention is currently devoted to the process of genetic divergence in wild populations, with emphases on gene flow, local adaptation, and their interactions. Indeed, adaptation in wild populations is supported in many species by many kinds of experiments based on both quantitative phenotypic traits and molecular data. However, the processes governing populations’ evolution are poorly understood in the tropical rainforest of Amazonia, and the relative influence of neutral and adaptive processes are continuously discussed. [br/]I am a young scientist interested in the process of genomic divergence in wild (tree) populations. I aimed at understanding how evolution structures the genetic diversity and governs molecular divergence in wild populations, with particular emphases on gene flow and local adaptation. During five years as a young scientist, I worked on answering the following questions, focusing on two tree species occupying vulnerable areas: mainly [i]Eperua falcata[/i] in Amazonia and, to a lesser extent, [i]Abies alba[/i] in the Mediterranean area.[br/][u]Scientific questions:[/u][br/]- Which evolutionary drivers are responsible of the structure of genetic diversity in wild populations occupying wide areas? This question was addressed at different geographical scales: from large (regional) to very local (microgeographic) scales. [br/]- What is the relative influence of neutral (gene flow, inbreeding) and adaptive drivers in the process of genetic divergence?[br/]- Is microgeographic adaptation possible in spite of extensive gene flow between populations occupying the extreme boundaries of an ecological gradient? [br/]- What is the extent of natural selection in the (whole) genome of wild populations? [br/][br/]My research work is at the interface between three promising disciplines: Evolutionary genomics (i.e. the study of populations evolution and the evolutionary drivers behind), Bioinformatics (i.e. the treatment of next-generation data), and Bayesian modelling (i.e. the empirical calibration of complex mechanistic model). I intend to take advantage of the recent advances in sequencing and informatic technologies to bring up to date the field of ecological genetics and evolutionary biology, by developing modern research strategies to study the process of genomic divergence in wild populations.
https://hal.archives-ouvertes.fr/hal-01204218

hal-01204218
https://hal.archives-ouvertes.fr/hal-01204218
PRODINRA : 286326

Éditeur(s) : American Geophysical Union
Résumé : [1] A multiproxy integrated chronological framework, based on oxygen and carbon stable isotope stratigraphy, biostratigraphy (foraminifera and nannoplankton bioevents and foraminifer assemblage-based climate cyclicity), magnetostratigraphy, sapropel stratigraphy, and C-14 AMS radiometric dates, has been achieved for borehole PRAD1-2, collected in 185.5 m water depth in the central Adriatic. This work was carried out within the European Community project Profiles across Mediterranean Sedimentary Systems (PROMESS1). The 71.2 m long borehole spans a time interval between late MIS 11 and MIS 1 (the last 370 ka), showing a chronological resolution of 500 and 250 years per cm during interglacial and glacial intervals, respectively. At present, this record is the most expanded and continuous marine record available for the Adriatic Basin. Several orbital cycles can be recognized in the PRAD1-2 record: the 100 ka glacial-interglacial fluctuations and the 23 ka precession-related cycles, which in turn control the deposition of sapropel layers. An integrated analysis of short-term oscillations within the Last Glaciation interval (MIS 4-MIS 2) allowed the identification of the Adriatic signature of Dansgaard-Oeschger events, showing the potential to achieve a more refined chronostratigraphic framework for the top part of the PRAD1-2 record. Finally, the age model obtained by this study allowed the chronological integration of the main foraminifera bioevents detected in the borehole as well as of the volcanoclastic layers present in the upper part of the record. Despite its proximal location, PRAD1-2 presents a continuous record and shows the potential to be consistently correlated both with deep-sea and continental records in the Mediterranean region and beyond.
Geochemistry Geophysics Geosystems (1525-2027) (American Geophysical Union), 2008 , Vol. 9 , P. NIL_107-NIL_127

Droits : 2008 American Geophysical Union
http://archimer.ifremer.fr/doc/2008/publication-3605.pdf
DOI:10.1029/2007GC001713
http://archimer.ifremer.fr/doc/00000/3605/

Éditeur(s) : HAL CCSD Elsevier
Résumé : Upper mantle flow beneath the French Massif Central is investigated using teleseismic shear wave splitting induced by seismic anisotropy. About 25 three component stations (short period, intermediate and broad-band) were installed during the period 1998-1999 in the southern Massif Central, from the Clermont Ferrand volcanic area to the Mediterranean sea. Teleseismic shear waves (SKS, SKKS and PKS) were used to determine the splitting parameters: the fast polarization direction and the delay time. Delay times ranging between 0.7 and 1.5 s have been observed at most of the sites. The azimuths of the fast split shear waves trend homogeneously NW-SE in the southern Massif Central suggesting a homogeneous mantle flow beneath this area. The observed NW-SE direction differs from the N100°E Pyrenean anisotropy further South. It does not appear to be correlated to Hercynian structures nor to the present-day motion of the plate but is well correlated to the Tertiary extension direction. We propose that the opening of the western Mediterranean induced by the rotation of the Corsica-Sardinia lithospheric bloc and the roll-back to the SE of the Tethys slab may have generated a large asthenospheric mantle flow beneath the southern Massif Central and a deflection of the up going plume centered beneath the northern Massif Central toward the SE.
ISSN: 0012-821X

insu-00150214
https://hal-insu.archives-ouvertes.fr/insu-00150214
https://hal-insu.archives-ouvertes.fr/insu-00150214/document
https://hal-insu.archives-ouvertes.fr/insu-00150214/file/Barruol_Granet_EPSL2002_hal.pdf
DOI : 10.1016/S0012-821X(02)00752-5

Éditeur(s) : Elsevier Science Bv
Résumé : The rollback of a segmented slab of oceanic lithosphere is typically accompanied by vertical lithospheric tear fault(s) along the lateral slab edge(s) and by strike slip movement in the upper plate, defined as a STEP fault (Subduction Tear Edge Propagator). The Neogene evolution of the Central Mediterranean is dominated by the interaction between the slow Africa–Eurasia convergence and the SE-ward rollback of the Ionian slab, that leads to the back-arc opening of the Tyrrhenian Sea. Here, we present post-stack time migrated and pre-stack depth migrated Archimede (1997) multichannel seismic lines, that were acquired offshore eastern Sicily, at the foot of the Malta escarpment. First, we identify the recent deformation along the lateral ramp of the Calabrian accretionary wedge. Towards the east, the Calabrian wedge is formed by the accretion of the post-evaporitic sediments, above a decollement at the base of the Messinian evaporites. At the latitude of Syracuse, 50 km east of the Malta escarpment, a major N150°E trending crustal scale and vertical fault slices through the entire accretionary wedge. This fault cuts by several kilometers, through the pre-evaporitic Messinian sediments and into the basement. The vertical offset along this vertical fault decreases from north to south, and the fault is no longer observed on the seismic lines, 50 km SE of the Alfeo seamount. A previously published Moho depth isocontour map, offshore Sicily and the recent GPS data, combined with the presence of strike slip movements NE onshore Sicily, allow us to identify this 200 km long crustal-scale fault as the surface expression of a STEP fault. The presence of syntectonic Pleistocene sediments on top this crustal-scale fault suggests a recent lithospheric vertical movement of the STEP fault, in response to the rollback of the Ionian slab and to the SE-ward advance of the Calabria-Peloritan block
Tectonophysics (0040-1951) (Elsevier Science Bv), 2013-08 , Vol. 602 , P. 141-152

Droits : 2013 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00118/22878/21386.pdf
DOI:10.1016/j.tecto.2012.12.026
http://archimer.ifremer.fr/doc/00118/22878/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Mediterranean geodynamic system is an exceptional natural laboratory to study the complexities of back-arc extension during subduction rollback. Corsica is a key locality that recorded the Alpine subduction-collision history followed by 30 Ma of the Apennines slab rollback, responsible for the successive opening, from West to East, of the Liguro-Provençal basin and the Tyrrhenian Sea. The overall strain pattern of the Alpine metamorphic units of Alpine Corsica is studied through a synthesis of i) available geological maps, ii) geochronological data and iii) newly acquired structural data relative to successive events of ductile and brittle extension, Three main stages of extension are recorded: 1/ Syn-metamorphic Oligocene extension accommodated by N140° trending ductile shear zones, that correspond to the reactivation of a major Alpine thrust; 2/ Burdigalian ramp-flat extension with N60°-70° trending fault zones that controlled the deposition of onshore piggy-back basins (e.g. St Florent basin), and 3/ Serravalian N-S trending fault zones. From a geodynamical point of view, these successive extensional deformations in Alpine Corsica can be correlated to the history of the Apennines slab rollback. The two first stages are related to a southeastward rollback of the Appennines slab that successively triggered: 1/ Continental rifting in Oligocene leading to the opening of the Liguro-Provençal basin and 2/ Burdigalian extension with N60°-70° trending fault zone, oblique to the Alpine thrust that, after a counterclockwise rotation of the Corso-Sardinian block, became unable to accommodate extension. Finally, the third stage that gave NS-trending fault zones developed in Serravalian, at the onset of Tyrrhenian rifting, related to an eastward rollback of the Apennines slab, as a response of slab tearing in Sicily.
ISSN: 0040-1951

insu-01424859
https://hal-insu.archives-ouvertes.fr/insu-01424859
https://hal-insu.archives-ouvertes.fr/insu-01424859/document
https://hal-insu.archives-ouvertes.fr/insu-01424859/file/gueydan-tectonoph-2017.pdf
DOI : 10.1016/j.tecto.2016.12.028

Éditeur(s) : Elsevier
Résumé : We present new results from the MARADJA'03 cruise depicting the geological structures offshore central and western Algeria. Using swath bathymetry and seismic reflection data, we map and discuss the offshore limits of the Internal Zones corresponding to relics of the AIKaPeCa domain that drifted and collided the African plate during the Miocene. We identify large reverse faults and folds that reactivate part of these limits and are still active today. The morphology of the westernmost NE-SW margin suggests a former strike-slip activity accommodating a westward block translation responsible for the shift of the Internal Zones towards the Moroccan Rif.
Nous présentons les résultats récents de la campagne MARADJA'03, qui visent à mettre en évidence les structures géologiques dans le domaine marin au nord-ouest de l'Algérie. Grâce aux données de bathymétrie multifaisceau et de sismique réflexion, nous cartographions et discutons les limites en mer des Zones internes correspondant aux reliques du domaine AlKaPeCa qui a dérivé, puis est entré en collision avec la plaque africaine au Miocène. De grandes failles inverses et plis, actifs dans le champ de contrainte actuel, réactivent certaines de ces limites. La marge ouest-algérienne, orientée NE¿SW, indique la présence d'une ancienne activité en décrochement ayant accommodé la translation des Zones internes vers l'ouest.
Comptes Rendus Geoscience (1631-0713) (Elsevier), 2006 , Vol. 338 , N. 1-2 , P. 80-91

Droits : 2005 Académie des sciences Published by Elsevier SAS
http://archimer.ifremer.fr/doc/2006/publication-1211.pdf
DOI:10.1016/j.crte.2005.11.009
http://archimer.ifremer.fr/doc/00000/1211/

Éditeur(s) : HAL CCSD
Résumé : Corsica is located in the Mediterranean sea, about 90 km from the Italian coast of Tuscany and 175 km from the French Riviera. This relatively large island stretches for 180 km in the north-south direction and 85 Km east-west. The rugged landscape, with a mean elevation of ca. 500 m and the highest point at 2710 m (Monte Cinto) is interrupted only by a major plain along the east coast. CorseAlp 2011 was held in April 2011. A link to the website is here: CorseAlp 2011. The CorseAlp field trips were designed to introduce the participants to the general features of the geology of Alpine Corsica and to recent specific discoveries. Field trip 1 focused on the geology of the Ocean-Continent Transition preserved in the Monte San Petrone, in Central Corsica, which was subducted to eclogite facies conditions during the Alpine orogeny. The three days post-workshop field trip (Field trip 2) focused on the general architecture of Alpine Corsica in an EW transect between the Balagne region and Bastia. The main topics of Field trip 1 and 2 allow discussion about the overall evolution of Alpine Corsica in the framework of Mediterranean geodynamics, with a focus on the most controversial aspects.
Journal of the Virtual Explorer

hal-00688965
https://hal.archives-ouvertes.fr/hal-00688965