Résumé : (Biographical) From Wikipedia: John Frank Stevens (25 April 1853 – 2 June 1943) was an American engineer who built the Great Northern Railway in the United States and was chief engineer on the Panama Canal between 1905 and 1907. Biography: Stevens was born in rural Maine, near West Gardiner to John Stevens, a tanner and farmer, and Harriet Leslie French. He attended Maine State Normal School (now the University of Maine at Farmington) for two years. At the conclusion of his schooling in 1873, bleak economic conditions held little promise of a job, and he chose to go west. Entry into the field of civil engineering evolved from his experience in the Minneapolis city engineer's office. For two years he carried out a variety of engineering tasks, including surveying and building railroads, and at the same time gained experience and an understanding of the subject. He became a practical engineer, self-taught and driven by a self-described "bull-dog tenacity of purpose." In 1878 Stevens married Harriet T. O'Brien. They had five children, two of whom died in infancy. By the age of 33, in 1886, Stevens was principal assistant engineer for the Duluth, South Shore and Atlantic Railway, and in charge of building the line from Duluth, Minnesota to Sault Ste. Marie, Michigan, across the Upper Peninsula of Michigan. Although a large part of his work involved surveying, he assisted in all phases of railroading: reconnaissance, locating, organizing, and construction. In 1889, Stevens was hired by James J. Hill as a locating engineer for the Great Northern Railway. Stevens earned wide acclaim in 1889 when he explored Marias Pass, Montana, and determined its practicability for a railroad. Stevens was an efficient administrator with remarkable technical skills and imagination. He discovered Stevens Pass through the Cascade Mountains, set railroad construction standards in the Mesabi Range of northern Minnesota, and supervised construction of the Oregon Trunk Line. Hill promoted him to chief engineer in 1895, and later to general manager. During his time at the Great Northern, Stevens built over a thousand miles of railroad, including the original Cascade Tunnel. Stevens Pass in the Cascade Range was named for him. (Most other Pacific Northwest landmarks with the word "Stevens" are named after Isaac Stevens, who is of no relation.) Panama Canal: Stevens left the Great Northern in 1903 for the Chicago, Rock Island and Pacific Railroad, where he was promoted to vice-president. Then, in 1905, at Hill's recommendation, he was hired by Theodore Roosevelt as chief engineer on the Panama Canal. Stevens' primary achievement in Panama was to build the infrastructure needed for the completion of the canal. "The digging," he said, "is the least thing of all." He proceeded immediately to build warehouses, machine shops, and piers. Communities for the personnel were planned and built to include housing, schools, hospitals, churches, and hotels. He authorized extensive sanitation and mosquito-control programs that eliminated yellow fever and other diseases from the Isthmus. Reflecting his background, he saw the early stage of the canal project itself as primarily a problem in railroad engineering, which included rebuilding the Panama Railway and devising a rail-based system for disposing of the soil from the excavations. Stevens argued the case against a sea level canal like the French had tried to build. He successfully convinced Theodore Roosevelt of the necessity of a high-level canal built with dams and locks. Resignation: Stevens resigned suddenly from the Canal project in 1907 to Roosevelt's great annoyance, as the focus of the work turned to construction of the canal itself. As a railroad engineer, Stevens had little expertise in building locks and dams, and probably realized he was no longer the best person for the remainder of the job. Stevens would also have been aware that the original great Cascade Tunnel, for which he was responsible, was in hindsight built in error too close to the ruling grade and was perhaps turning from a credit to a debit. The true reasons for his resignation have never been known. Subsequent career: Following the collapse of Imperial Russia in 1917, leaders of the provisional government appealed to President Wilson for help with their transportation systems. Stevens was selected to chair a board of prominent U.S. railroad experts sent to Russia to rationalize and manage a system that was in disarray; among his work was on the Trans-Siberian Railway. After the overthrow of the provisional government, the board's work ceased. Stevens remained in Allied-occupied Manchuria and in 1919 headed the Inter-Allied Technical Board charged with the administration and operation of the Chinese Eastern and Siberian railways. He remained in an advisory capacity until occupying Allied troops were withdrawn; he finally left in 1923. After his return to the United States Stevens continued to work as a consulting engineer, ending his career in Baltimore in the early 1930s. He was awarded the Franklin Institute's Franklin Medal in 1930. He then retired to Southern Pines, North Carolina, where he died at the age of 90 in 1943.
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http://ufdc.ufl.edu/AA00029596/00001

Résumé : Julius B. Annis was born June 4, 1890 in Luvno, Hungary. At present there is nothing known of his parentage, or when he emigrated to the United States. It is known that he registered for the draft during World War One and at that time he was residing at Brooklyn, New York. He married Minnie Brosow before 1917 and had at least one child, Morton Lawrence Annis Sr. It is evident that Julius became affiliated with one of the larger and well known cigar companies, "Sanchez and Haya" in New York City. A brief history of this cigar company and it's founders is in order, so that the evolution of the company can be seen in regards to "J. B. Annis". "Fact & Fancy About Cigars and Tobacco", by Morton L. Annis Sr. (1967) In 1867, Senors Ignacio Haya and Serfino Sanchez, natives of Spain came to New York City with $1000.00 in capital and started what was to become one of the most successful cigar manufacturies in the world. In 1886 they moved their operations to Tampa, Florida and they received the U.S. Revenue designation of "Factory No. 1". Tampa soon became the cigar manufacturing industry giant and Sanchez & Haya retained it's leadership roll. The company ultimately acquired and merged with many of the old-line Tampa producers, such as Morgan Cigar Co., Schwab-Davis y Cia. and many more. By 1892, both Senor Haya and Sanchez were leaders of the Spanish community and their financial ability, philanthropy, and industry were legendary. J. B. (Bunny) Annis began as a "drummer", or cigar salesman, who traveled from coast to coast selling his wares to Tobacconist and cigar merchants. "Dapper, loquacious, true bon vivants of the era .. perhaps the original American Salesman." Julius Annis, was at this time a guiding spirit and became partners in what is now known as Gradiaz, Annis or "Gradiaz y Annis", and was the Dean of these legendary "Knights of the Panetela." In 1963 Gradiaz Annis became a Division of General Cigar Co., Inc. Julius Benjamin Annis died the following year (June 1964) in Tampa. His son, Morton Lawrence Annis Sr. (1917-1979), President of Gradiaz, Annis, wrote about his father in 1967: "My father had a basic compelling motivation for excellence of product which was, in truth, his religion and his way of life. His love for tobacco and fine cigars was sacrosanct and so traditional in concept that he vigorously opposed all modern technological advances, preferring to create cigars in the great classic style of his youth." Gradiaz, Annis is still known world wide as "World Leader in Luxury Cigars".
(Funding) Funded in part by the Institute for Museum and Library Services (IMLS), Ephemeral Cities Project.
Tampa |z 1271000 |2 ceeus
Hillsborough County |z 12057 |2 ceeus
United States of America -- Florida -- Hillsborough County -- Tampa

Droits : All rights reserved. 2005.
R01-10928

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In Western Mediterranean, the Rif belt in Morocco is part of the Gibraltar Arc built during the Tertiary in the framework of Eurasia-Africa convergence. The structural and metamorphic evolution of the internal units of this belt as well as their timing, crucial to constrain the geodynamic evolution of the Alboran Sea, is still largely debated.Our study on the Ceuta Peninsula (Northern Rif) provides new structural, petrological and geochronological data (U-Th-Pb, Ar-Ar), which allow to precise the tectono-metamorphic evolution of the Lower Sebtides metamorphic units with:(1) a syn-metamorphic thrusting event developed under granulite facies conditions (7–10 kbar and 780–820 °C). A major thrust zone, the Ceuta Shear Zone, drove the emplacement of metapelites and peridotitic lenses from the Ceuta Upper Unit over the orthogneisses of the Monte Hacho Lower Unit. This compressional event ended during the Upper Oligocene.(2) an extensional event developed at the boundary between amphibolite and greenschist facies conditions (400–550 °C and 1–3 kbar). During this event, the Ceuta Shear Zone has been reactivated as a normal fault. Normal ductile shear zones contributed to the final exhumation of the metamorphic units during the Early Miocene.We propose that the compressional event is related to the formation of an orogenic wedge located in the upper plate, in a backward position, of the subduction zone driving the geodynamic evolution of the Alboran domain. In this context, the episode of lithospheric thinning could be related to the opening of the Alboran basin in a back-arc position.Furthermore, unlike the previous models proposed for the Rif belt, the tectonic coupling between mantle peridotites and crustal metamorphic rocks occurred in Ceuta Peninsula at a depth of 20–30 km under high temperature conditions, before the extensional event, and thus cannot be related to the back-arc extension.
ISSN: 0040-1951

insu-01682810
https://hal-insu.archives-ouvertes.fr/insu-01682810
DOI : 10.1016/j.tecto.2017.11.028

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Superposed to ductile syn-metamorphic deformations, post-foliation deformations affect metamorphic units during their exhumation. Understanding the role of such deformations in the structuration of metamorphic units is key for understanding the tectonic evolution of convergence zones. We characterize post-foliations deformations using 3D modelling which is a first-order tool to describe complex geological structures, but a challenging task where based only on surface data. We propose a modelling procedure that combines fast draft models (interpolation of orientation data), with more complex ones where the structural context is better understood (implicit modelling), allowing us to build a 3D geometrical model of Syros Island blueschists (Cyclades), based on field data. With our approach, the 3D model is able to capture the complex present-day geometry of the island, mainly controlled by the su-perposition of three types of post-metamorphic deformations affecting the original metamorphic pile: i) a top-to-South ramp-flat extensional system that dominates the overall island structure, ii) large-scale folding of the metamorphic units associated with ramp-flat extensional system, and iii) steeply-dipping normal faults trending dominantly NNW-SSE and EW. The 3D surfaces produced by this method match outcrop data, are geologically consistent, and provide reasonable estimates of geological structures in poorly constrained areas.
ISSN: 0191-8141

insu-01188400
https://hal-insu.archives-ouvertes.fr/insu-01188400
DOI : 10.1016/j.jsg.2015.07.002

Éditeur(s) : HAL CCSD
Résumé : The Franceville Basin (2.1 Ga) in southeastern Gabon, hosts a black shale series well preserved (FB Formation) which represents an exceptional example of unmetamorphised Paleoproterozoic sediment strata. This basin includes the protore of one of the largest Mn-oxide laterite ore worldwide, mined by Eramet-Comilog. The aim of this this work is to determine formation conditions of this protore and to characterize the global sedimentary evolution of the FB Formation which include the protore. This 75 m thick protore is constituted of Mn carbonate-rich black shales which represent a potential ore deposit for the future. It was drilled, on the Bangombé plateau, during a recent campaign of 24 boreholes with an average depth of 125 m.Through multidisciplinary study on these cores and key outcrops of the basin, this work focuses on : i) the depositional environment of the Mn-protore and FB Formation ; ii) the processes of formation of the Mn-carbonates at 2.1 Ga and iii) the architecture and distribution of Mn-rich levels of the protore on the Bangombé Plateau.A detailed sedimentological and petrological study allowed us to redefine the division of the FB into nine units, named U1 to U9 from the base to the top. These units show a fine upward cycle up to U5 and a reverse coarse loop until U9. This division leads to a new interpretation to propose an evolution from a shoreface depositional environment controlled by deltaic currents (U1) to an offshore depositional environment with anoxic conditions (U2). In this basin, a system of submarine fan is developed, feeding a network of sand injections (injectites) covering the Bangombé plateau (70 km²) and with a thickness of 150 m affecting U4 to U7, including the Mn-protore. The protore depositional environment formed below the wave base limit (U4, U5 and U6) in a starved basin, controlled by biochemical sedimentation allowed the formation of Mn-carbonates. The end of starved basin, would allow the re-opening of the detrital input into the offshore basin (U7). This basin is then filled by storm bar deposits intersected by deltaic sub-aquatic channels (U8). The U9 unit corresponds to a quiet lagoon environment, allowing the multicellular organism development for the first time on the planet.A geochemical study allowed the characterization of the depositional environment of Mn-carbonates as an anoxic to sub-oxic and alkaline environment. For the first time, we showed that the manganese carbonates, present as bacteriomorph forms, are precipitated from the seawater by the mediated photosynthetic cyanobacterial activity, which allows CO2 / HCO3 depression of the environment and a local increase of pH. The cyanobacterial activity is controlled by the absence of bottom currents, which increase the detrital input. This would stop the activity of the cyanobacteria and thus would lead to the decrease of the Mn-concentration along the protore.Finally, well-log and a sequential correlation analyses allowed us to detail spatial and timing repartition of FB Formation deposit, controlled by a tectono-sedimentary model. We propose two- tectono-sedimentary phases. A first syn-tectonic phase (U1 to U3) controls the depocentres and sedimentation gaps. Turbidite coarse deposits are located in the most subsident part, clay deposits rather on the slope and carbonates on shoals. A second post-tectonic phase (U4 to U7) allows isopach deposits. The Mn-protore formed during the post-tectonic phase. However, it shows a variable thickness due to subsidence to the north of the Bangombé plateau. So, on the Bangombé plateau, Mn-contents increase towards the south, whereas the protore thickness increases towards the NNE. Moreover sand injectites decrease Mn-content in the eastern part of the Bangombé plateau and impact on the economic evaluation of the Mn-carbonates. Currently, the protore is structured by post-sedimentary faults, which lead to a non-continuity of the high Mn levels on the Bangombé plateau.
Le Bassin de Franceville situé au SE du Gabon présente une série de black shales (Formation FB) d'âge Paléoprotérozoïque (2,1 Ga) surmontant les grès de la Formation FA. Ce bassin peu déformé et non métamorphique représente une archive exceptionnelle des processus de dépôt de cette période de l’histoire de la Terre où la vie commence à se développer. En particulier, la Formation FB contient le protore d'un gisement mondial d'oxydes de manganèse exploité par la société Eramet-Comilog. L’objectif de ce travail est de préciser les conditions de formation de ce protore et de le replacer dans l’histoire du remplissage du bassin. Ce protore d'une épaisseur moyenne de 75 m est constitué de carbonates de manganèse ; il a fait l'objet d'une récente campagne de 24 forages carottés d'une profondeur moyenne de 125 m sur le plateau de Bangombé.A travers une approche pluridisciplinaire comprenant l'étude de ces forages et des affleurements clefs du bassin, ce travail porte sur la caractérisation i) de l'environnement de dépôt du protore et des séries qui l'encadrent (du toit du FA au toit du FB) ; ii) du mode de formation des carbonates de Mn à 2,1 Ga et iii) de l'architecture et de la répartition des hautes teneurs en Mn du protore qui représente un gisement potentiel du futur.L’étude pétro-sédimentaire détaillée a permis de distinguer neuf unités (U1 à U9) au sein de la Formation FB organisées suivant un cycle rétrogradant jusqu’à U5 puis progradant jusqu’à U9. Ce découpage montre une évolution du milieu de dépôt depuis un domaine de shoreface contrôlé par des courants deltaïques (U1) évoluant vers des dépôts d’offshore restreint (U2). Ce bassin enregistre ensuite un système de chenaux-levées turbiditiques (U3) qui alimentent un réseau d'injectites reconnu sur l’ensemble du Pl. de Bangombé et qui traverse 150 m de série (U4 à U7) en affectant le protore et ainsi les teneurs en Mn. L'environnement de dépôt du protore (U5 et U6) marque l’isolement du bassin qui devient affamé et contrôlé par une sédimentation biochimique à l’origine du dépôt des carbonates de Mn. L'Unité 7 correspond à la réouverture des apports détritiques en domaine d'offshore supérieur puis en domaine de shoreface dominé par des dépôts de tempêtes et de chenaux sous-aquatiques deltaïques (U8), et enfin lagunaire (U9) dans lequel apparaissent les premiers métazoaires de l’histoire de la planète, suivant une séquence régressive.Une étude géochimique a permis de préciser les conditions de dépôt du protore qui se forme en milieu alcalin anoxique à sub-oxique. Dans ce milieu, nous montrons pour la première fois une précipitation directe des carbonates de Mn sous forme bactériomorphe induite par l'activité photosynthétique des cyanobactéries qui consomment le CO2/HCO3 et conduisent à une augmentation du pH favorable à la formation des carbonates de Mn. L'activité cyanobactérienne est conditionnée par l’absence de courants de fond qui augmentent la turbidité du milieu et stoppent cette dernière.Les corrélations diagraphiques et séquentielles permettent de préciser la répartition spatiale et temporelle du FB permettant ainsi de replacer le protore dans l’histoire tectono-sédimentaire du bassin. Une première phase syn-tectonique (U1 à U3) contrôle l’épaisseur et la mise en place de dépôts turbiditiques dans les parties subsidentes, de dépôts argileux sur les pentes et de dépôt de carbonates sur les hauts-fonds. La seconde phase post tectonique (U4 à U7) permet la mise en place de dépôts relativement isopaques, bien que le protore enregistre une subsidence plus importante au nord du Pl. de Bangombé. On observe ainsi, sur le Plateau de Bangombé, des teneurs en Mn qui augmentent vers le sud alors que l’épaisseur du protore augmente vers le NNE. Postérieurement au dépôt du FB, le protore est structuré par des failles qui le compartimentent en touches de piano limitant ainsi sa continuité sur le Plateau de Bangombé.
https://hal.archives-ouvertes.fr/tel-01621460

tel-01621460
https://hal.archives-ouvertes.fr/tel-01621460
https://hal.archives-ouvertes.fr/tel-01621460/document
https://hal.archives-ouvertes.fr/tel-01621460/file/these_Dubois2017-MnGabon.pdf

Éditeur(s) : Université de la Réunion
Résumé : The green turtle (Chelonia mydas) is an emblematic species of marine life. However, nowadays it is subject to many threats (poaching, by-catch). Even if there is deep growing measures for its protection, the green turtle still is an endangered species and it is listed in Appendix I of Washington Convention (CITES). In order to elaborate efficient conservation and management plans, perfect knowledge of green turtle biology, but also of its population structure and their characteristics, are needed. In this thesis, we have assessed genetic structure of green turtle populations in the South-Western Indian Ocean by using genetic tools. In all, 1551 tissue samples have been collected from our study zone and from our control site French Polynesia (37 samples). All kinds if individuals were sampled (except males in reproductive phase) from 15 sampling sites including nesting, foraging, and immature development site. We used both control region of mitochondrial DNA and 6 microsatellite loci to better infer maternal and paternal lineages. We identified 29 haplotypes in the South-Western Indian Ocean. They are distributed in 3 independent and highly divergent clades, including one composed with haplotypes from Atlantic Ocean. For 7 of these haplotypes, it was the first time they were detected in the study zone. Fifteen haplotypes were previously undescribed, distributed in all the 3 clades. These new haplotypes seem to be specific to the South-Western Indian Ocean, which is then an original zone. Besides, we found a high allelic richness. These results show the South-western Indian Ocean is rich and very diversified. This region plays an important role in the global diversity of the species. The South-Western Indian Ocean is one of the two contact zones presently known between the two metapopulations of green turtles (Atlantic-Mediterranean and Indo-Pacific). This contact induces a genetic cline based on CM8 (Atlantic) and C3 (Indo-Pacific) haplotype frequencies. Analysis of the microsatellite differentiation between individuals provides evidence of genetic exchanges between the two metapopulations in the region. The South-Western Indian Ocean participates to green turtle global genetic mixing. Studying the influence of several intrinsic and extrinsic factors on population structuring provides useful information for management plan elaboration. We found no significant difference between genetic structures of foraging females and males, contrary to immature turtles which seem to be organised in 'regional pools'. This organisation could be due to both immature natal homing and influence of oceanic currents. High mitochondrial differentiation of nesting females and low global microsatellite differentiation of our samples indicate male-mediated gene flow among populations of the study zone. The genetic composition of a sampling site presents no significant variation along the year, even if we could notice some trends. Nevertheless, it can be significantly different from a year to an other one. This may result from alternation of distinct populations on the same site. We noticed different evolution in 10 or 20 years of the genetic composition depending on the sampling site. Geographic distance seems not to have significant influence on population structuring concerning microsatellite markers. Nesting females of Saziley Beach (Mayotte Island, Comoros Archipelago) present genetic divergence from females nesting in the two other sampled beaches of this island. The observed population structure shows no contradiction with the organisation of oceanic currents in the South-Western Indian Ocean. Comparing the results from the two genetic markers used, we identified 8 genetic differentiated clusters of turtles in the study zone and at least 6 distinct populations. These clusters constitute 8 potential management units (MUs) which could serve as basis in the elaboration of conservation and management plans.
La tortue verte (Chelonia mydas) constitue l'un des espèces emblématiques de la vie marine, pourtant de nombreuses menaces pèsent de nos jours encore sur sa survie (braconnage, captures accidentelles). Ainsi, malgré l'essor de mesures de protection menées à travers pour sa sauvegarde, la tortue verte constitue une espèce 'en danger d'extinction' et figure dans l'Annexe I de la Convention de Washington (CITES). Afin d'élaborer des plans de gestion et de conservation qui soient efficaces, il est important d'avoir une parfaite connaissance de la biologie de la tortue verte, mais aussi de la structure de ses populations et de leurs caractéristiques. C'est dans ce cadre que s'inscrit la présente étude. L'objectif de cette étude était d'acquérir des connaissances sur la structure des populations de tortues vertes dans le sud-ouest de l'océan Indien grâce à l'utilisation de l'outil génétique. Au total, 1551 échantillons de tissu ont été collectés dans la zone d'étude et dans notre site témoin la Polynésie française (37 échantillons). Toutes les catégories d'individus ont été échantillonnées (excepté les mâles en phase de reproduction) et les 15 sites d'échantillonnage comprennent à la fois des sites de ponte, d'alimentation et de développement pour les immatures. Deux types de marqueurs ont été utilisés : la région contrôle de l'ADN mitochondrial et 6 loci microsatellites, afin d'appréhender au mieux l'apport des lignées maternelles et paternelles. Nous avons pu mettre en évidence la présence dans le sud-ouest de l'océan Indien de 29 haplotypes distincts, appartenant à trois clades fortement divergents dont l'un constitué d'haplotypes originaires de l'océan Atlantique. Parmi ces haplotypes, 7 ont été détectés pour la première fois dans la zone d'étude, et 15 autres n'ont jamais été précédemment décrits chez cette espèce. Ils sont présents dans chacun des 3 clades d'haplotypes. Ces nouveaux haplotypes semblent spécifiques à la région, et en font une zone originale. On observe par ailleurs une grande richesse allélique dans les effectifs analysés. Ces résultats montrent que le sud-ouest de l'océan Indien est une zone riche et très diversifiée. Cette région joue un rôle important dans la diversité génétique globale de l'espèce. Le sud-ouest de l'océan Indien constitue l'une des deux seules zones connues à l'heure actuelle de contact entre les deux métapopulations de tortues vertes (Atlantique-Méditerranée et Indo-Pacifique). Ce contact a entraîné la formation d'un cline génétique portant principalement sur les fréquences relatives des haplotypes CM8 (Atlantique) et C3 (Indo-Pacifique). Les résultats obtenus lors de l'analyse microsatellite de la différenciation entre les individus originaires des deux métapopulations montrent que le sud-ouest de l'océan Indien constitue une zone d'échanges génétiques entre les deux métapopulations, participant au brasage génétique de l'espèce. L'étude de facteurs, intrinsèques et extrinsèques, pouvant influencer la structuration des populations apportent de nombreuses informations qui pourraient s'avérer utiles lors de l'élaboration de plans de gestion. La structure des femelles et des mâles en alimentation ne diffère pas, contrairement à celle des immatures qui semble s'organiser en 'pools régionaux' qui seraient le fruit de l'interaction d'un comportement de philopatrie et d'une influence des courants océaniques. La forte différenciation mitochondriale des femelles en ponte et la très faible différenciation microsatellite observée à l'échelle de la région, indiquent l'existence de flux de gènes via les mâles. La composition génétique d'un site ne varie pas de manière significative au cours de l'année. Par contre, elle peut varier d'une année à l'autre, signifiant l'alternance dans certains sites de ponte de plusieurs populations distinctes. L'évolution de la composition génétique d'un groupe, au cours de 10 ou 20 ans, diffère selon le site considéré. La distance ne semble pas influencer de manière significative la structuration des populations au niveau microsatellite. Les femelles en ponte sur la plage de Saziley (Mayotte) diffèrent génétiquement de celles pondant sur les deux autres plages de l'île. La structure observée des populations est en accord avec l'organisation des courants océanique dans la région. La confrontation des résultats obtenus à partir des deux marqueurs génétiques utilisés, permet la détermination de 8 ensembles génétiquement différenciés dans la zone d'étude et l'identification d'au moins 6 populations distinctes. Ces ensembles constituent autant d'unités de gestion (MUs) potentielles qui pourront servir de base à l'élaboration de plans de gestion et de conservation.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/these-3532.pdf
http://archimer.ifremer.fr/doc/00000/3532/

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

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

Éditeur(s) : HAL CCSD American Geophysical Union (AGU)
Résumé : International audience
The El Oro metamorphic province of SW Ecuador is a composite massif made of juxtaposed terranes of both continental and oceanic affinity that has been located in a fore-arc position since Late Paleozoic times. Various geochemical, geochronological, and metamorphic studies have been undertaken on the El Oro metamorphic province, providing an understanding of the origin and age of the distinct units. However, the internal structures and geodynamic evolution of this area remain poorly understood. Our structural analysis and thermal modeling in the El Oro metamorphic province show that this fore-arc zone underwent four main geological events. (1) During Triassic times (230–225 Ma), the emplacement of the Piedras gabbroic unit at crustal-root level (~9 kbar) triggered partial melting of the metasedimentary sequence under an E-W extensional regime at pressure-temperature conditions ranging from 4.5 to 8.5 kbar and from 650 to 900°C for the migmatitic unit. (2) At 226 Ma, the tectonic underplating of the Arenillas-Panupalí oceanic unit (9 kbar and 300°C) thermally sealed the fore-arc region. (3) Around the Jurassic-Cretaceous boundary, the shift from trench-normal to trench-parallel subduction triggered the exhumation and underplating of the high-pressure, oceanic Raspas Ophiolitic Complex (18 kbar and 600°C) beneath the El Oro Group (130–120 Ma). This was followed by the opening of a NE-SW pull-apart basin, which tilted the massif along an E-W subhorizontal axis (110 Ma). (4) In Late Cretaceous times, an N-S compressional event generated heterogeneous deformation due to the presence of the Cretaceous Celica volcanic arc, which acted as a buttress and predominantly affected the central and eastern part of the massif.
ISSN: 0278-7407

hal-01115714
https://hal.archives-ouvertes.fr/hal-01115714
DOI : 10.1002/2014TC003618

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
During the last decade, the interaction of deep processes in the lithosphere and mantle with surface processes (erosion, climate, sea-level, subsidence, glacio-isostatic readjustment) has been the subject of heated discussion. The use of a multidisciplinary approach linking geology, geophysics, geodesy, modelling, and geotechnology has led to the awareness of coupled deep and surface processes. Deep earth dynamics (topography, erosion, tectonics) are strongly connected to natural hazards such as earthquakes, landslides, and tsunamis; sedimentary mass transfers have important consequences on isostatic movements and on georesources, geothermal energy repartitions. The ability to read and understand the link between deep Earth dynamics and surface processes has therefore important societal impacts. Ground-truthing at carefully-selected sites of investigation is imperative to better understand these connections.Due to its youth (<30 Ma) and its subsidence history, the almost land-locked Gulf of Lion–Sardinia continental margins system provides a unique record of sedimentary deposition from the Miocene to present. Due to its high subsidence rate, palaeoclimatic variations, tectonic events and vertical evolution are all recorded here at very high resolution. The late Miocene isolation and desiccation of the Mediterranean, the youngest and most catastrophic event, the Messinian Salinity Crisis (MSC), induced drastic changes in marine environments: widespread deposition of evaporite (gypsum, anhydrite and halite) in the central basin, and intense subaerial erosion along its periphery. These extraordinary mass transfers from land to sea induced strong isostatic re-adjustments that are archived in the sedimentary record and represent a window to the lithospheric rheology and the deep processes.The GOLD (Gulf of Lion Drilling) project, proposes to explore this unique sedimentary record as well as the nature of the deep crustal structure, providing valuable information about the mechanisms underlying vertical motions in basins and their margins.
ISSN: 0264-8172

insu-01197393
https://hal-insu.archives-ouvertes.fr/insu-01197393
https://hal-insu.archives-ouvertes.fr/insu-01197393/document
https://hal-insu.archives-ouvertes.fr/insu-01197393/file/Rabineau%20et%20al.-final-MPG2014_REVISED-FINAL-No-Marked_FINAL%2BFigures.pdf
DOI : 10.1016/j.marpetgeo.2015.03.018

Éditeur(s) : Elsevier
Résumé : Analysis of new high-resolution seismic-reflection profiles, chirp profiles and previously published sidescan data, together with piston cores on the Danube Fan provide new insight into the recent sedimentation processes in the deep northwestern Black Sea.The latest channel-levee system on the Danube Fan developed probably during the Neoeuxinian lowstand (oxygene isotope stage 2) in a semi-freshwater basin with a water level about 100 m lower than today. Sediment supplied by the Danube was transported to the deep basin through the Viteaz Canyon, which was directly connected to the leveed channel of this system on the middle slope. Channel avulsion was common in the middle fan, as indicated by four main phases of bifurcation. Each phase developed after the same pattern: breaching of the lower and narrower left levee by turbidity currents, building of a unit of High Amplitude Reflection Packets (HARP) by the unchannelized flow while the former channel was abandoned, followed by initiation of a new meandering leveed channel. The northward migration through successive bifurcations is influenced by the asymmetry between levees, hence by the Coriolis effect. In the lower fan where the levees became too low to maintain a stable pathway for the turbiditic flows, channel migration occurred. Locations of HARPs and channels after bifurcation are controlled by the pre-existing bathymetry. Sedimentary deposits are confined between the high levees of unit 0 (the initial phase of the youngest channel-levee system) to the south, and the steep relief of the Dniepr Fan to the north.The HARPs of the most recent phase of avulsion are the most severely constrained by local topography and form a very narrow elongate structure that is at most half as thick as the previous HARPs. Their distal part is not covered by channel-levee systems and is visible both on sidescan mosaics and on chirp profiles and was sampled in core BLKS 98-20.Sea level controlled fan activity but the evolution of the last channel-levee system with several bifurcations during a single sea level lowstand suggests that the primary control of channel avulsion and sand delivery is probably autocyclic.The presence of important HARP sand bodies in the mud-rich Danube Fan is presumed by analogy with a similar seismic facies on the Amazon Fan and indicated by the sands cored in BLKS98-20. However, only drilling of the HARP units could verify this interpretation.
Marine Geology (0025-3227) (Elsevier), 2001-09 , Vol. 179 , N. 1-2 , P. 25-37

Droits : 2001 Elsevier Science B.V. All rights reserved
http://archimer.ifremer.fr/doc/2001/publication-474.pdf
DOI:10.1016/S0025-3227(01)00197-9
http://archimer.ifremer.fr/doc/00000/474/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Sur fond de crise du tourisme au Nord, de la globalisation de l’économie et de l’accélération des mobilités, une évolution des formes de développement touristiques semble à l’œuvre dans les confins géographiques. Dans certains territoires touristiques du fait de conflits dans l’usage des ressources naturelles, des pratiques récréatives alternatives émergent qui combinent une logique économique avec des préoccupations socio-environnementales.Notre article analyse l’apparition du tourisme scientifique dans la région « non-touristique » de Aysén, en Patagonie chilienne. Des acteurs d’un territoire se mobilisent selon des pôles culturels et des axes thématiques autour de projets pilotes, de recherche expérientielle et de médiations scientifiques innovantes. Sur ce front pionnier, un réseau informel d’acteurs coordonne ses actions pour aborder les problématiques sociales et environnementales de leur territoire. Opérateurs et prestataires pour le tourisme scientifique créent de manière participative une offre originale. Un système touristique alternatif, axé sur la protection de l’environnement, de la culture et des dynamiques sociales de la communauté d’accueil, favorise l’acquisition et le partage de savoirs entre scientifiques, acteurs locaux et visiteurs.Le tourisme scientifique s’inscrit-il dans une évolution globale des pratiques touristiques ? En proposant de dépasser les frontières, entre activités récréatives et le travail, de lieux de vie et de loisir, il apparaît comme l’expression d’un « après-tourisme ». L’hybridation des pratiques, une approche scientifique associée à l’esprit de la découverte inhérent au voyage, semble pouvoir relever des défis sociétaux liés à l’essor d’un tourisme globalisé. Alors que le tourisme est pensé depuis longtemps en termes de transfert de compétences, de modèles et d’ingénierie du Nord vers le Sud, une périphérie propose de nouveaux cadres de pensée, d’action et de participation qui renouvellent le sens du voyage.
In the context of a tourism crisis in the north, a globalized economy and an increase of mobility, a change in the forms of tourism development seems to occur in peripheral areas. In some tourism areas and due to conflicts over the use of natural resources, alternative recreational practices arise that combine economic needs and socio-environmental concerns.Our article analyzes the appearance of scientific tourism in the "non-tourist" region of Aysén, in Chilean Patagonia. Actors of a territory unite according to specific cultural poles and thematic axes through experiential research and innovative scientific mediation pilot projects. On this pioneer front, an informal network of stakeholders coordinates its actions to address the social and environmental issues of their territory. Operators and service providers for scientific tourism create an innovative offer in a participatory process. An alternative tourism system, focused on protecting the environment, the culture and social dynamics of the host community, promotes the acquisition and sharing of knowledge between scientists, local actors and visitors.Is scientific tourism part of a global evolution of tourism practices? By proposing to go beyond established boundaries, of recreational activities and work, everyday places and leisure areas, it appears as the expression of an “After-Tourism”. The hybridization of practices, a scientific approach associated with the spirit of the discovery inherent of the travel experience, seems to respond to the challenges of the community confronted to the rise of a globalized tourism. While tourism has always been thought of in terms of transfer of skills, models and engineering from the North to the South, a periphery offers new frameworks of thought, action and participation that renew the meaning of travel.
En un escenario de crisis del turismo en los países desarrollados, de la globalización de la economía y del incremento de las movilidades, una evolución de las formas de desarrollo del turismo parece estar en marcha en los confines geográficos. En ciertos territorios turísticos, debido a los conflictos de uso de los recursos naturales, prácticas recreativas alternativas surgen que combinan una lógica económica con preocupaciones socio-ambientales.El presente artículo analiza el surgimiento del turismo científico en la región “no-turística” de Aysén en la Patagonia chilena. Actores del territorio se unen según polos y temáticas científicas, a través de proyectos pilotos, de investigación experiencial y mediaciones científicas innovadoras. En este frente pionero, una red informal se organiza para abordar las problemáticas sociales y ambientales de su territorio. Operadores y proveedores de servicios para el turismo científico crean de manera participativa una oferta novedosa. Un sistema turístico alternativo, basado en el cuidado del medio ambiente, de la cultura y de las dinámicas sociales del comunidad de acogida, favorece la adquisición y el intercambio de conocimientos entre científicos, actores locales y visitantes. ¿Será la aparición del turismo científico la expresión de una evolución global de las practicas turísticas? Al invitar a que sean sobrepasadas las fronteras, entre actividades recreativas y el trabajo, lugares de vida y sitios de esparcimiento, este se presenta como un “Pos-Turismo”. La hibridación de las prácticas, una aproximación científica asociada al espíritu de descubrimiento inherente del viaje, parece poder resolver los desafíos de nuestras sociedades vinculados al auge de un turismo globalizado. Cuando el turismo suele ser pensado desde hace mucho, como un proceso de transferencia de capacidades, de modelos y de ingenierías, del Norte hacia el Sur, una periferia propone nuevos marcos conceptuales, de acción y de participación, que renuevan el sentido del viaje.
Patagonie

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.11169
http://journals.openedition.org/etudescaribeennes/11169

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
Convergent plate margins typically experience a transition from subduction to collision dynamics as massive continental blocks enter the subduction channel. Studies of high-pressure rocks indicate that tectonic fragments are rapidly exhumed from eclogite facies to mid-crustal levels, but the details of such dynamics are controversial. To understand the dynamics of a subduction channel we report the results of a petrochronological study from the central Sesia Zone, a key element of the internal Western Alps. This comprises two polymetamorphic basement complexes (Eclogitic Micaschist Complex and Gneiss Minuti Complex) and a thin, dismembered cover sequence (Scalaro Unit) associated with pre-Alpine metagabbros and metasediments (Bonze Unit). Structurally controlled samples from three of these units (Eclogitic Micaschist Complex and Scalaro-Bonze Units) yield unequivocal petrological and geochronological evidence of two distinct high-pressure stages. Ages (U-Th-Pb) of growth zones in accessory allanite and zircon, combined with inclusion and textural relationships, can be tied to the multi-stage evolution of single samples. Two independent tectono-metamorphic 'slices' showing a coherent metamorphic evolution during a given time interval have been recognized: the Fondo slice (which includes Scalaro and Bonze rocks) and the Druer slice (belonging to the Eclogitic Micaschist Complex). The new data indicate separate stages of deformation at eclogite-facies conditions for each recognized independent kilometer-sized tectono-metamorphic slice, between ∼85 and 60 Ma, with evidence of intermittent decompression (ΔP ∼ 0*5 GPa) within only the Fondo slice. The evolution path of the Druer slice indicates a different P-T-time evolution with prolonged eclogite-facies metamorphism between ∼85 and 75 Ma. Our approach, combining structural, petrological and geochronological techniques, yields field-based constraints on the duration and rates of dynamics within a subduction channel.
ISSN: 0022-3530

hal-01054335
https://hal.archives-ouvertes.fr/hal-01054335
DOI : 10.1093/petrology/egu029

Éditeur(s) : HAL CCSD National Academy of Sciences
Résumé : International audience
All evolutionary biologists are familiar with evolutionary units that evolve by vertical descent in a tree-like fashion in single lineages. However, many other kinds of processes contribute to evolutionary diversity. In vertical descent, the genetic material of a particular evolutionary unit is propagated by replication inside its own lineage. In what we call introgressive descent, the genetic material of a particular evolutionary unit propagates into different host structures and is replicated within these host structures. Thus, introgressive descent generates a variety of evolutionary units and leaves recognizable patterns in resemblance networks. We characterize six kinds of evolutionary units, of which five involve mosaic lineages generated by introgressive descent. To facilitate detection of these units in resemblance networks, we introduce terminology based on two notions, P3s (subgraphs of three nodes: A, B, and C) and mosaic P3s, and suggest an apparatus for systematic detection of introgressive descent. Mosaic P3s correspond to a distinct type of evolutionary bond that is orthogonal to the bonds of kinship and genealogy usually examined by evolutionary biologists. We argue that recognition of these evolutionary bonds stimulates radical rethinking of key questions in evolutionary biology (e.g., the relations among evolutionary players in very early phases of evolutionary history, the origin and emergence of novelties, and the production of new lineages). This line of research will expand the study of biological complexity beyond the usual genealogical bonds, revealing additional sources of biodiversity. It provides an important step to a more realistic pluralist treatment of evolutionary complexity.
ISSN: 0027-8424

hal-01544803
https://hal.archives-ouvertes.fr/hal-01544803
DOI : 10.1073/pnas.1206541109

Éditeur(s) : HAL CCSD Elsevier
Résumé : Vegetation phenology is the study of the timing of seasonal events that are considered to be the result of adaptive responses to climate variations on short and long time scales. In the field of remote sensing of vegetation phenology, phenological metrics are derived from time series of optical data. For that purpose, considerable effort has been specifically focused on developing noise reduction and cloud-contaminated data removal techniques to improve the quality of remotely-sensed time series. Comparative studies between time series composed of satellite data acquired under clear and cloudy conditions and from radiometric data obtained with high accuracy from ground-based measurements constitute a direct and effective way to assess the operational use and limitations of remote sensing for predicting the main plant phenological events. In the present paper, we sought to explicitly evaluate the potential use of MODerate resolution Imaging Spectroradiometer (MODIS) remote sensing data for monitoring the seasonal dynamics of different types of vegetation cover that are representative of the major terrestrial biomes, including temperate deciduous forests, evergreen forests, African savannah, and crops. After cloud screening and filtering, we compared the temporal patterns and phenological metrics derived from in situ NDVI time series and from MODIS daily and 16-composite products. We also evaluated the effects of residual noise and the influence of data gaps in MODIS NDVI time series on the identification of the most relevant metrics for vegetation phenology monitoring. The results show that the inflexion points of a model fitted to a MODIS NDVI time series allow accurate estimates of the onset of greenness in the spring and the onset of yellowing in the autumn in deciduous forests (RMSE <= one week). Phenological metrics identical to those provided with the MODIS Global Vegetation Phenology product (MDC12Q2) are less robust to data gaps, and they can be subject to large biases of approximately two weeks or more during the autumn phenological transitions. In the evergreen forests, in situ NDVI time series describe the phenology with high fidelity despite small temporal changes in the canopy foliage. However, MODIS is unable to provide consistent phenological patterns. In crops and savannah, MODIS NDVI time series reproduce the general temporal patterns of phenology, but significant discrepancies appear between MODIS and ground-based NDVI time series during very localized periods of time depending on the weather conditions and spatial heterogeneity within the MODIS pixel. In the rainforest, the temporal pattern exhibited by a MODIS 16-day composite NDVI time series is more likely due to a pattern of noise in the NDVI data structure according to both rainy and dry seasons rather than to phenological changes. More investigations are needed, but in all cases, this result leads us to conclude that MODIS time series in tropical rainforests should be interpreted with great caution. (C) 2013 Elsevier Inc. All rights reserved.
ISSN: 0034-4257

hal-01032407
https://hal.archives-ouvertes.fr/hal-01032407
DOI : 10.1016/j.rse.2013.01.010

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : La prostitution est une problématique très intéressante d’une part parce qu’elle est transversale à tous les temps, à toutes les classes sociales, à tous les espaces, et d’autre part parce qu’il s’agit d’un fléau qui se conjugue le plus souvent au féminin. Il s’agit à mon sens du versant spécifique d’une problématique universelle dont personne ne peut s’affranchir sans mettre en jeu l’ensemble de la condition humaine. En effet, la prostitution est le lieu où convergent et se concentrent de façon exacerbée tous les maux d’une société. La femme est malgré elle au centre de ce système dans lequel on retrouve les frustrations, les rapports de domination, de pouvoir, la violence, la misère, la corruption, l’aliénation… La prostitution, tout comme le concept de genre, est une construction sociale, dans laquelle les femmes sont enfermées réellement et symboliquement.D’autre part, si les maux d’une société sont décuplés dans le système de la prostitution, nulle part ailleurs n’existe un tel abîme entre fantasme et réalité. C’est le lieu des fausses représentations et des euphémismes comme le montrent ces deux expressions édulcorées « zones de tolérance » et « femmes publiques ». A Cuba, malgré les tentatives d’éradication de la prostitution dans les premières décennies qui suivirent le triomphe de la Révolution de 1959, la chute du bloc soviétique et la période de pénurie qui s’ensuivit donnèrent lieu à un retour de cette prostitution, sous de nouvelles formes qui persistent aujourd’hui. Cependant, il fut une époque, celle de la première République (1902-1958) durant laquelle Cuba, rongée par un système néocolonial, connût une recrudescence de ce phénomène, dans des proportions jamais égalées. Une époque somme toute récente où les zones de tolérance, espaces où étaient regroupées les maisons closes, occupaient une grande partie de La Havane coloniale ainsi que des quartiers entiers à travers l’île. A l’intérieur de ces zones très lucratives dont profitaient à la fois les proxénètes, policiers, politiques et hommes d’affaires, les femmes cubaines, mais également, dans une grande proportion des Françaises victimes de la traite des Blanches, se trouvaient au cœur d’un système qui étaient à lui seul le symptôme de la frustration néocoloniale, mais également de l’exacerbation du patriarcat.Cette problématique, on ne peut plus actuelle, convoque la pluridisciplinarité, c’est pourquoi j’ai eu recours à des témoignages de prostituées depuis le début du siècle jusqu’à la Révolution, recueillis et publiés à Cuba. Je me suis penchée sur les différents discours sur la prostitution de l’époque, discours politiques et féministes. Les rapports de police, les plaintes déposées par des femmes, les comptes rendus de procès, et les descriptions des médecins-hygiénistes sont autant de sources qui viennent corroborer les témoignages.
The republican era in Cuba is a complex and difficult one for the Cuban population. 1898 remains engraved in people’s memories as being a time of great disillusion for a population who, having freed itself from Spanish colonial domination, was deprived of independence by the United States of America. Three years of American intervention sufficed to put power bases into place, guarantee maximal exploitation conditions and organize the legal framework of the American domination over Cuba by means of the Platt Amendment in 1901. The protectorate set up by the United States, followed by a neocolonial system in 1934, relies upon the collaboration of presidents and corrupt governments succeeding each other in power. Corruption, nepotism and violence are put in place in a society in which inequality is dramatically worsening and all moral values are disintegrating. In this context and in a Cuban society governed with patriarchal rules, women are the first victims of the system. After the wars of independence, the only options they have are marriage, work or prostitution. Legitimate marriage is only available to a privileged few. With regards to employment, only 9.8% of women have the opportunity to work and this percentage didn’t change until 1959. It was at this time that prostitution reached unprecedented levels. It wasn’t just the case of a few marginalized women but of thousands of mothers, wives, widows and working women who were trapped in this alienating condition, forced to sell their bodies. Legislation and violence are used to control and restrict the work space for prostitutes, removing these ‘streetwalkers’ from the public eye, grouping them together in tolerance zones with very strict rules, which are in reality in the hands of Cuban and French procurers, and subjecting them to constant inspections carried out by hygienists who physically and symbolically assault women’s bodies. What is more, speeches about prostitution, whether made by politicians, feminists, journalists, doctors or mere observers, contribute significantly to a certain representation of these women. While debates about prostitution have recently shaken public opinion, this work refers back to an episode of Cuba’s history which brings us to reflect upon the evolution of the phenomenon and on its protean nature.
Cuba

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.6945
http://journals.openedition.org/etudescaribeennes/6945

Éditeur(s) : HAL CCSD European Geosciences Union
Résumé : International audience
The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter productivity measurements), their associated canopy photosynthetic capacity (enhanced vegetation index, EVI) and climate, we ask how carbon assimilation and aboveground allocation are related to climate seasonality in tropical forests and how they interact in the seasonal carbon cycle. We found that canopy photosynthetic capacity seasonality responds positively to precipitation when rainfall is < 2000 mm yr(-1) (water-limited forests) and to radiation otherwise (light-limited forests). On the other hand, independent of climate limitations, wood productivity and litterfall are driven by seasonal variation in precipitation and evapotranspiration, respectively. Consequently, light-limited forests present an asynchronism between canopy photosynthetic capacity and wood productivity. First-order control by precipitation likely indicates a decrease in tropical forest productivity in a drier climate in water-limited forest, and in current light-limited forest with future rainfall < 2000 mm yr(-1).
ISSN: 1726-4170

hal-01557759
https://hal.univ-lorraine.fr/hal-01557759
https://hal.univ-lorraine.fr/hal-01557759/document
https://hal.univ-lorraine.fr/hal-01557759/file/bg-13-2537-2016.pdf
DOI : 10.5194/bg-13-2537-2016

Éditeur(s) : HAL CCSD Geological Society of America
Résumé : orogenic wedges
Interaction between surface and tectonic processes plays a key role in the structural evolution, kinematics, and exhumation of rocks in orogenic wedges. The deformation patterns observed in analog models show that strain partitioning has a strong impact on the vertical component of displacement of tectonic units, which in return favors erosion in domains of important uplift. Partitioning is controlled by tectonic processes and by climate-dependent surface processes, including erosion and sedimentation. The effects of partitioning include localization of deformed domains, exhumation above areas of deep underplating, and steady-state maintenance of wedges for long time periods. Simple models illustrate well how the morphostructural evolution of mountain belts is determined by these complex interactions.
ISSN: 1052-5173

hal-00558931
https://hal.archives-ouvertes.fr/hal-00558931
DOI : 10.1130/GSATG48A.1

Éditeur(s) : Elsevier Science Bv
Résumé : The breakup of Pangea and onset of growth of the Pacific plate led to several paleoenvironmental feedbacks, which radically affected paleoclimate and ocean chemistry during the Jurassic. Overall, this period was characterized by intense volcanic degassing from large igneous provinces and circum-Panthalassan arcs, new oceanic circulation patterns, and changes in heat and humidity transports affecting continental weathering. Few studies, however, have attempted to unravel the global interactions linking these processes over the long-term. In this paper, we address this question by documenting the global changes in continental drainage and surface oceanic circulation for the whole Jurassic period. For this purpose, we present 53 new neodymium isotope values (εNd(t)) measured on well-dated fossil fish teeth, ichthyosaur bones, phosphatized nodules, phosphatized ooids, and clastic sediments from Europe, western Russia, and North America. Combined with an extensive compilation of published εNd(t) data, our results show that the continental sources of Nd were very heterogeneous across the world. Volcanic inputs from a Jurassic equivalent of the modern Pacific Ring of Fire contributed to radiogenic εNd(t) values (− 4 ε-units) in the Panthalassa Ocean. For the Tethyan Ocean, the average surface seawater signal was less radiogenic in the equatorial region (− 6.3), and gradually lower toward the epicontinental peri-Tethyan (− 7.4), western Russian (− 7.4) and Euro-Boreal seas (− 8.6). Different Nd sources contributed to this disparity, with radiogenic Nd influxes from westward Panthalassan currents or juvenile volcanic arcs in open oceanic domains, and substantial unradiogenic inputs from old Laurasian and Gondwanan shields for the NW Tethyan platforms. Overall, the εNd(t) values of Euro-Boreal, peri-Tethyan, and western Russian waters varied quite similarly through time, in response to regional changes in oceanic circulation, paleoclimate, continental drainage, and volcanism. Three positive shifts in εNd(t) values occurred successively in these epicontinental seas during the Pliensbachian, in the Aalenian-Bathonian interval, and in the mid-Oxfordian. The first and third events are interpreted as regional incursions of warm surface radiogenic currents from low latitudes. The Aalenian-Bathonian shift seems linked to volcanic outbursts in the NW Tethys and/or circulation of deep currents resulting from extensional events in the Hispanic Corridor and reduced influences of boreal currents crossing the Viking Corridor. In contrast, the εNd(t) signals decreased and remained very low (< − 8) during the global warming events of the Toarcian and Late Oxfordian - Early Tithonian intervals. In these greenhouse contexts, a latitudinal expansion of humid belts could have extended the drainage pathways toward boreal Nd sources of Precambrian age and increased the supply of very unradiogenic crustal-derived inputs to seawater. Finally, a brief negative εNd(t) excursion recorded in parallel with regional drops in seawater temperature suggests that southward circulation of cold unradiogenic Arctic waters occurred in the NW Tethys in the Callovian - Early Oxfordian. All these results show that changes in surface oceanic circulation resulting from the Pangean breakup could have regionally impacted the evolution of seawater temperatures in the NW Tethys.
Gondwana Research (1342-937X) (Elsevier Science Bv), 2015-06 , Vol. 27 , N. 4 , P. 1599-1615

Droits : 2014 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/00179/29015/27443.pdf
DOI:10.1016/j.gr.2014.02.006
http://archimer.ifremer.fr/doc/00179/29015/

Éditeur(s) : Université de Bucarest - Université de Bretagne occidentale
Résumé : This study is focusing on the architecture and recent sedimentary evolution of the Danube channel, the youngest channel-levee system in the Danube deep-sea fan. The study was conducted as part of the BlaSON French-Romanian Project, and combined high-resolution seismic-reflection profiles and chirp profiles with multibeam bathymetry and piston cores. This data set was acquired in 1998 during a joint survey IFREMER-GeoEcoMar of the north-western Black Sea. Previous seismic and acoustic data were also used. The Danube deep-sea fan is a large passive-margin mud-rich fan. Like the other systems of this type (Amazon fan, Mississippi fan or Indus fan) the Danube fan consists of stacked channel-levee systems intercalated with mass-transport deposits. Seismic and sedimentary facies in the Danube fan are similar to those identified in most of the mud-rich systems. Nevertheless, the Danube fan is distinguished by a specific feature: its development in a freshwater environment. This is due to the peculiar water-level history of the Black Sea controlled by the link to the Mediterranean through the Strait of Bosphorus and the Sea of Marmara. This connexion was successively interrupted (during sea level lowstands) and re-established (when the sea level was rising above the Bosphorus). Temporary absence of marine water influx during lowstands together with large freshwater inputs from the Danube and other major rivers changed the Black Sea into a freshwater lake during times of fan activity. This peculiarity possibly favourised the development of hyperpycnal flow at the Danube mouth and the initiation of turbidity currents in the deep-sea fan. The Danube channel is directly connected to the large shelf-indenting Danube canyon (also known as Viteaz canyon). The Danube canyon is deeply incised into the shelf margin for 26 km landward of the shelfbreak. During lowstands this canyon acted as the most important path for sediment supply to the deep sea in this part of the continental margin. It consists of a main trough with steep flanks, and a meandering thalweg cut into the flat canyon floor, attesting for the development of the canyon by erosion in the entrenched axial thalweg. Sections with specific morphology, orientation and gradient identified along the canyon, are interpreted as phases of landward expansion of the canyon. Internal structure of the canyon shows several erosional surfaces, which indicate that the present morphology of the canyon is the result of its polyphasic evolution. Instability in the zone of the canyon is related to the important sediment supply at the Danube mouth, to the presence of the gas in the surficial sediment, and possibly under a structural control. The upper part of the Danube channel (between the Danube canyon and ~1400 m depth) consists in a single leveed-channel that has undergone significant overbank deposition, as attested by the well-developed levees. The levees are strongly asymmetrical, being higher and wider on the right-hand side looking downstream. This type of asymmetry is rather common in deep-sea fans, and is generally attributed to the Coriolis effect (Menard, 1955). The channel is slightly sinuous, partially filled and incised by an entrenched thalweg, connected to the axial thalweg of the Danube canyon. Detailed seismic investigation inside the channel trough documented several depositional phases within the channel fill, separated by erosional surfaces. These surfaces are associated with distinct terraces identified on the multibeam bathymetry, that can be followed downward along the main trough axis. The valley fill deposits (where not removed by the subsequent erosional event) show an axial HAR (High Amplitude Reflections) seismic facies with lateral lower amplitude continuous reflections consisting in a levee facies, as proved by sampling. This indicates that filling up was associated with flow within the channel, and not with interruption of fan activity. On the middle slope below 1400 m, this single channel bifurcates through repeated avulsions. As a result, several highly meandering channels developed. The onlap relationships between these channels indicate that only one channel was active at a time. Each phase of avulsion resulted in a depositional unit consisting in a basal unchannelized lobe defined as High Amplitude Reflection Packets (HARP, Flood et al., 1991) that underlies a channel-levee system. The deposition of HARPs was associated with the readjustment of the longitudinal profile of the channel after the breaching of a levee, which resulted in remobilization of upslope channel deposits and eroded levees. When this adjustment was complete, erosion ceased and levees began to develop above the HARPs (Pirmez et al., 1997). All the identified phases of avulsion followed the same pattern: (1) breaching of the lower and narrower left levee; (2) building of a unit of High Amplitude Reflector Packets (HARP) basinward of the bifurcation point by the unchannelized flow, while the former channel was abandoned; and (3) initiation of a new meandering leveed channel. The northward migration of the resulting units through repeated bifurcations is influenced by the asymmetry between levees (hence by the Coriolis effect), and confined between the high levees of the initial phase of the Danube channel (to the south) and the steep relief of the Dniepr fan (to the north). Structure of the fan valley fill indicate that the erosional surfaces inside the upper channel could be formed in response of successive avulsions, by the adjustment of the longitudinal profile of the channel following the breaching of a levee wall. Sediments removed by erosion formed the HARP lobes basinward of the avulsion point. When this adjustment was complete, a channel-levee system developed downward of the bifurcation, overlying the HARPs, but also upward of this point, as a confined channel-levee system inside the erosional trough of the fan valley. Fluvial incisions identified on the continental shelf, together with the coastline location during the last active period of the Danube channel, indicated that the paleo-Danube was directed towards the head of the Danube canyon. Paleo-Danube mouth was fairly close (ca. 10 km) to the Danube canyon, supplying sediment to the Danube channel. Furthermore, hyperpycnal flow probably prevailed in the freshwater environment that characterized the Black Sea during times of fan activity. These conditions would have enabled the development of a quasi-continuous river-canyon-deep-sea fan system, ensuring the effective transfer of the sediment between the coastal zone and the deep sea.
Ce travail est consacré à l'étude de l'architecture et de l'évolution sédimentaire récente de l'éventail profond du Danube, en particulier de son dernier système chenal-levée: le chenal du Danube. L'étude a été réalisée dans le cadre du projet de coopération franco-roumaine BlaSON, à partir des données sismiques, bathymétriques-acoustiques et sédimentologiques acquises en 1998 lors d'une campagne en mer Noire réalisée par IFREMER et GeoEcoMar. Des données sismiques et acoustiques antérieures ont été également utilisées. L'éventail profond du Danube s'enserre dans la catégorie des grands éventails vaseux. Comme les autres systèmes de ce genre (tel que les éventails de l'Amazone, du Mississippi ou de l'Indus) il est constitué d'une succession de systèmes chenaux-levées intercalés avec des dépôts de transport en masse. Le fonctionnement de l'éventail était conditionné par la baisse du niveau marin lors des périodes glaciaires. Ses faciès sismiques et sédimentaires s'apparentent aux faciès qui caractérisent la plupart des éventails de ce type. L'éventail du Danube constitue néanmoins un cas particulier parmi les autres systèmes étudiés, du fait de son fonctionnement dans un bassin lacustre. Ceci est dû à la situation spécifique de la mer Noire dont la connexion avec la Méditerranée, par le détroit de Bosphore et la mer de Marmara, a été successivement interrompue (au cours de périodes de bas niveau) et reprise (quand le niveau marin remontait en dépassant le seuil du Bosphore). L'absence de l'apport d'eau salée pendant les périodes glaciaires, associée avec l'augmentation de l'apport fluvial, ont déterminé l'installation d'un milieu d'eau douce dans la mer Noire à chaque fois que la baisse du niveau permettait la reprise du fonctionnement de l'éventail profond. Cette situation particulière aurait favorisé la formation des courants hyperpycnaux à l'embouchure d'un fleuve du débit du Danube qui déversait ses eaux turbides dans un bassin lacustre, et aurait donc influencé l'apparition de courants de turbidité dans l'éventail profond. Le chenal du Danube s'est développé sur la pente continentale en prolongation du canyon du Danube (ou Viteaz) auquel il est directement connecté. Le canyon est incisé de manière significative (26 km) dans la plate-forme continentale. Au cours de bas-niveaux marins il constituait la principale voie de transfert des sédiments terrigènes vers le bassin profond dans cette partie de la marge. Le canyon est constitué par une entaille avec des flancs abrupts et un talweg axial incisé, qui montre l'importance du processus d'érosion du fond pour le développement du canyon. Les segments qui ont été identifiés le long du canyon, avec des morphologies, des orientations et des pentes spécifiques, sont interprétés comme des phases d'avancement du canyon vers la côte. Plusieurs incisions sont visibles dans la structure interne du canyon et témoignent que la morphologie actuelle du canyon est le résultat de son évolution polyphasée. L'instabilité de la zone du canyon est en relation avec les apports sédimentaires importants à l'embouchure du Danube, avec la présence du gaz dans les sédiments superficiels, et possiblement sous un contrôle structural. Sur la pente supérieure (entre le canyon du Danube et environ 1400 m de profondeur) le chenal du Danube présente des levées bien développées et fortement asymétriques, avec la levée droite plus haute et plus large que la levée gauche. Ce type d'asymétrie, fréquemment décrit dans les éventails profonds est généralement attribué à l'effet Coriolis (Menard, 1955). Le chenal est légèrement sinueux, partiellement comblé et incisé par un talweg axial qui représente la continuation sur la pente du talweg incisé dans le canyon du Danube. L'analyse sismique détaillée du remplissage de la vallée montre plusieurs phases de dépôt, séparées par des discontinuités érosives. Ces surfaces d'érosion correspondent à des terrasses emboîtées, relativement parallèles le long de la vallée, visibles dans la bathymétrie. Les dépôts qui constituent le remplissage du chenal présentent un faciès sismique de type HAR (High Amplitude Reflections) dans l'axe du chenal, partiellement (ou parfois totalement) enlevé par les phases d'érosion subséquentes, qui continue latéralement avec des réflexions litées correspondant à un faciès sédimentaire de levée. Le remplissage de la vallée a été donc associé avec des écoulements dans le chenal, et non pas avec l'interruption de son fonctionnement. Sur la pente inférieure, le chenal unique bifurque plusieurs fois par avulsion et forme de nouveaux systèmes chenaux-levées méandriformes. Ces systèmes se succèdent verticalement en onlap, ce qui montre qu'un seul chenal a été actif à la fois. Chaque phase d'avulsion a eu comme résultat la mise en place d'une unité constituée par un lobe défini comme "High Amplitude Reflection Packets" (HARP, Flood et al., 1991) à la base, et un système chenal-levée au sommet. Le dépôt d'un lobe HARP est associé avec de l'érosion dans le chenal en amont du point d'avulsion pour l'ajustement de son profil après la rupture de la levée. Quand le chenal a retrouvé son profil d'équilibre, l'érosion a cessé et des levées ont commencé à se développer au-dessus des HARPs (Pirmez et al., 1997). Toutes les phases d'avulsion se sont développées d'après le même modèle: (1) la rupture de la levée gauche, plus étroite; (2) le dépôt d'un lobe HARP par les écoulements non-chenalisés en aval du point d'avulsion, et l'abandon de l'ancien chenal; (3) l'initiation d'un nouveau système chenal-levée. La migration systématique du chenal vers le nord est influencée par l'assymétrie des levées (donc par la force de Coriolis), et confinée entre les grandes levées de la phase initiale du chenal du Danube, au sud, et le relief abrupt de l'éventail du Dniepr au nord. La structure sédimentaire du chenal du Danube indique que les surfaces érosives à l'intérieur du remplissage du chenal se seraient formées en réponse aux avulsions, du fait de l'ajustement du profil du chenal après la rupture d'une levée. Les sédiments du chenal érodés au cours de ce processus ont formé les lobes HARP. Quand le chenal a retrouvé son profil d'équilibre, un système chenal-levée s'est développé en aval du point d'avulsion au dessus du lobe HARP, mais aussi en amont de ce point, où il se trouve confiné dans la vallée érosive. Les incisions fluviatiles identifiés sur la plate-forme continentale et la position de la ligne de côte pendant la dernière période d'activité du chenal du Danube montrent que le paléo-Danube se dirigeait directement vers la tête du canyon du Danube. Son embouchure était située à proximité du canyon, qui alimentait le chenal du Danube. Cependant, les courants hyperpycnaux devaient prévaloir dans le milieu de salinité réduite qui caractérisait la mer Noire lors des périodes actives de l'éventail. Ces conditions auraient favorisé la mise en place d'un système quasi-continu fleuve-canyon-éventail profond, qui contrôlait le transfert des sédiments entre la côte et le bassin profond.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2002/these-1206.pdf
http://archimer.ifremer.fr/doc/00000/1206/

Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : International audience
Andros is a key island for understanding both the timing of high-pressure–low-temperature(HP-LT) metamorphism and the dynamics of crustal-scale detachment systems exhuming high-gradeunits in the Cyclades (Greece). Using phengite 40Ar–39Ar geochronology coupled with thermobarometry,as well as data from literature, we constrain the pressure–temperature–time (P-T-t) paths of theMakrotantalon and Attic–Cycladic Blueschist units on Andros. Peak conditions of the HP-LT episodein the Makrotantalon unit are 550 °C and 18.5 kbar, dated at 116 Ma. We correlate this episode withEarly Cretaceous blueschist facies metamorphism recognized in the Pelagonian zone of continentalGreece. This is a new argument favouring a Pelagonian origin for the Makrotantalon unit. In the Attic–Cycladic Blueschist unit, the P-T-t path is characterized by: (1) exhumation after peak conditions inHP-LT conditions between 55 and 35 Ma; (2) isobaric heating at 7 kbar until 30 Ma; and (3) isothermaldecompression until 21 Ma. This thermal evolution and timing are similar to those of the neighbouringTinos Island, emphasizing major thermal re-equilibration at the transition between stable and retreatingsubduction. Modifications of the crustal thermal state played a major role in the evolution of the NorthCycladic Detachment System, below which Andros HP-LT units were exhumed.
ISSN: 0016-7568

insu-01114909
https://hal-insu.archives-ouvertes.fr/insu-01114909
DOI : 10.1017/S0016756814000661