Éditeur(s) : E & W Blunt ( New York )
Résumé : "Engraved for the American Coast Pilot" Original edition published in 1769.
(Funding) Funded in part by the University of Florida, the Florida Heritage Project of the State University Libraries of Florida, the Institute for Museum and Library Services, and the U.S. Department of Education's TICFIA granting program.
(Statement of Responsibility) Published by Edmund & William Blunt
Mexico -- Veracruz -- Veracruz
Veracruz (Veracruz-Llave, Mexico)
Mexico
Veracruz (Veracruz-Llave)
Veracruz (Veracruz-Llave, Mexico)

Droits : This item is presumed to be in the public domain. The University of Florida George A. Smathers Libraries respect the intellectual property rights of others and do not claim any copyright interest in this item. Users of this work have responsibility for determining copyright status prior to reusing, publishing or reproducing this item for purposes other than what is allowed by fair use or other copyright exemptions. Any reuse of this item in excess of fair use or other copyright exemptions may require permission of the copyright holder. The Smathers Libraries would like to learn more about this item and invite individuals or organizations to contact Digital Services (UFDC@uflib.ufl.edu) with any additional information they can provide.
002490859
AMK6510
http://ufdc.ufl.edu/UF00073299/00001

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Big storm events represent a major risk for populations and infrastructures settled on coastal lowlands. In the Western Mediterranean, where human societies colonized and occupied the coastal areas since the Ancient times, the variability of storm activity for the past three millennia was investigated with a multi-proxy sedimentological and geochemical study from a lagoonal sequence. Mappings of the geochemistry and magnetic susceptibility of detrital sources in the watershed of the lagoon and from the coastal barriers were undertaken in order to track the terrestrial or coastal/marine origin of sediments deposited into the lagoon. The multi-proxy analysis shows that coarser material, low magnetic susceptibility, and high strontium content characterize the sedimentological signature of the paleostorm levels identified in the lagoonal sequence. A comparison with North Atlantic and Western Mediterranean paleoclimate proxies shows that the phases of high storm activity occurred during cold periods, suggesting a climatically-controlled mechanism for the occurrence of these storm periods. Besides, an in-phase storm activity pattern is found between the Western Mediterranean and Northern Europe. Spectral analyses performed on the Sr content revealed a new 270-year solar-driven pattern of storm cyclicity. For the last 3000 years, this 270-year cycle defines a succession of ten major storm periods (SP) with a mean duration of 96 ± 54 yr. Periods of higher storm activity are recorded from >680 to 560 cal yr BC (SP10, end of the Iron Age Cold Period), from 140 to 820 cal yr AD (SP7 to SP5) with a climax of storminess between 400 and 800 cal yr AD (Dark Ages Cold Period), and from 1230 to >1800 cal yr AD (SP3 to SP1, Little Ice Age). Periods of low storm activity occurred from 560 cal yr BC to 140 cal yr AD (SP9 and SP8, Roman Warm Period) and from 820 to 1230 cal yr AD (SP4, Medieval Warm Period).
ISSN: 0277-3791

hal-01277796
https://hal.archives-ouvertes.fr/hal-01277796
DOI : 10.1016/j.quascirev.2015.10.009

Éditeur(s) : Littoral 2004, Aberdeen, Scotland, UK, September 2004
Résumé : NAMIBIE (a french acronym for Integrated Multimedia Navigator Within Coastal Environment Data Bases) is a specific tool which first concept has been established by Ifremer and has been developped by an association between research in the field of coastal environment, innovation in the field of new information and communication technologies and services in the field of coastal integrated management and impact studies. The objectives of this tool are to facilitate research, direct access and display of relevant multimedia coastal integrated data and information according to an interactive, widely opened and playfull interface. The principles are based upon the fact that sustainable decision making needs an optimized unterstanding of coastal processes and better consultation between actors. In this purpose the development of the tool has considered that the end-user should and could be free to look after the data and the information he needs for a particular site or environment of interest and for a specific ICZM question according to easy navigation interfaces. That is why NAMIBIE concept is based upon : - a coherent 3D representation of the coasts (i.e. from catchement areas to continental shelf and deep sea), which considers a coherent DEM from land to sea and textural representation of the environment using satellite imagery textural displays, - a 3D navigator which allows the user to fly or dive over and within the coastal environment of interest, - a multimedia database (text, graphs, image, maps, geographic objects, modelling results...) specific to the territory of interest, - an interactive interface which helps in finding relevant information associated to specific questions. The technologies used include VRML data format, integration of standard GIS format (shp, grid, img) within the navigator, integration and display of modelling data. The production chain is realized in C++ and Java scripts allow dialogue between web pages and 3D windows. Applications are presented on the coasts of Languedoc Roussillon region (French Mediterranean border) in the framework of ICZM problematics

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00089/20055/17696.pdf
http://archimer.ifremer.fr/doc/00089/20055/

Éditeur(s) : Elsevier Science Bv
Résumé : Estuaries and coastal waters are essential nursery habitats for many marine species, and especially for flatfishes. Thus, investigating how anthropogenic disturbances affect the quality of these habitats is of major importance to understand their consequences on the population renewal of marine species. The aim of the present study was to analyse the effects of estuarine habitat degradation on the population of the common sole in the Eastern Channel, a key species in the fish community and fisheries in this area. We especially focused on the drastic drop in the surface area and on the low water quality of the Seine estuary, the main river of the Eastern Channel. A geographic Information System (GIS) was used to develop quantitative maps of sole nursery habitats in the Eastern Channel by using a habitat suitability model based on bathymetry and sediment structure. This approach indicated that juvenile densities are low in the Seine estuary with regards to other nursery sectors. Then, thanks to historical maps of the Seine estuary, habitat suitability maps were built for key dates in the modifications of this estuary since 1850. This backward predictive approach suggests that habitat loss in the Seine estuary has led to a 42% decrease of its nursery capacity. As the density of juvenile sole in the Seine estuary is low in comparison to other sectors, this represents only a 3% loss at the sole population scale, in the Eastern Channel. However, when we assumed that prior to anthropogenic disturbance the juvenile density in the Seine estuary might have been equivalent to the current density of adjacent sectors with higher quality, the loss in abundance could be nearly 23% (8-36%). Results suggest that the loss in habitat surface combined with habitat degradation has led to an important loss in the contribution of the Seine estuary nursery to the whole sole population in the Eastern Channel. (C) 2009 Elsevier BM. All rights reserved.
Journal Of Sea Research (1385-1101) (Elsevier Science Bv), 2010-07 , Vol. 64 , N. 1-2 , P. 34-44

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/00008/11921/9799.pdf
DOI:10.1016/j.seares.2009.08.003
http://archimer.ifremer.fr/doc/00008/11921/

Éditeur(s) : Wiley InterScience
Résumé : This paper reports on the status and design of the operational remotely operated vehicle Victor 6000, rated for 6000 m depth and of the 3000 m depth autonomous underwater vehicle Asterxx operated by Ifremer the French Institute for Sea Exploitation. Victor 6000 is part of a global system built of subsystems, scientific modules, winch and cable, dead weight and umbilical, positioning subsystem using acoustic ultra short base line (USBL) techniques, and software for data and dive management. In 2005 the system was equipped with a second toolsled dedicated to high resolution mapping of the sea bed, with both acoustical and optical devices. Asterxx, the first autonomous underwater vehicle (AUV) developed by IFREMER, is 4.5 m in length with a diameter of 0.69 m. Depending on the payload, its weight is between 600 and 800 kg in air,with a diving depth of 3000 m. Its cruising speed is between 0.5 and 2.5 ms. The AUV is capable of carrying various payloads for a wide spectrum of applications. The vehicle can cruise up to 100 km. For coastal applications this vehicle is operable by a limited crew potentially from a nonspecialized vessel. Both vehicles are used for oceanography as well as to continually evolve underwater systems to address new scientific challenges.
Journal of Field Robotics (1556-4959) (Wiley InterScience), 2007-06 , Vol. 24 , N. 6 , P. 449-459

Droits : 2007 Wiley InterScience
http://archimer.ifremer.fr/doc/2007/publication-2806.pdf
DOI:10.1002/rob.20195
http://archimer.ifremer.fr/doc/00000/2806/

Éditeur(s) : Elsevier
Résumé : The study, which is based on repetitive bathymetric surveys, assesses changes and effects of one of the most important floods recorded in the Rhone Delta area: bottom morphology and sediment distribution in the Rhone outlet after the December 2003 flood are discussed by comparison between Digital Terrain maps (DTMs) of November 2003 and January 2004. The post-flood morphology shows that the whole of the system is active, mainly in the east. The channel of the Rhbne has been hollowed out on the left bank by more than 5 m, the eastern coast of the mouth has retreated 400 m, the mouth-bar has prograded 200 m and the slope of the delta front has increased by 0.19. The overlay of pre- and post-flood DTMs makes it possible to estimate the total volume deposited in the [0 to -20 m] zone as +7.8 X 10(6) m(3) (i.e. 0.88 m(3) m(-2)), which corresponds to 4 X 10(6) t of sediment. These values are compared with the average annual volume of 0.47 X 10(6) m(3) yr(-1) of sediment deposited in this zone between 1995 and 2003, as well as the average sediment load estimated at the Arles station (50 km upstream) for this flood event (3.1 x 10(6) t to 5.3 x 10(6) t). The acquisition of bathymetric measurements immediately before and after a major flood allows more than a simple morphological description; in addition, an analysis of the solid load transfer processes towards the prodelta is achievable. Three mechanisms are highlighted. Most of the material eroded in the channel and supplied to the delta front corresponds to fine sediment that drape homogeneously over the pre-flood morphology of the delta front. The transit of the coarsest sediment (primarily sand) is slowed down in the channel of the Rh6ne: this sediment builds up in relatively small areas, leading to the formation of gullies on the prodelta slope. The gullies have fixed positions and disappear gradually towards the west, following the progressive migration of the active band towards the east. These old features are not reactivated by floods occurring after their formation. During the flood, only a small volume of coarse sediment bypasses through the gullies, and the fine deposits are remobilised rapidly or compacted. Flood input concerns essentially the delta front, which traps 90% of the fluvial solid discharge between 0 and 20 m depth. The coarse prodelta supply is then due mainly to mass movements of unconsolidated material deposited beforehand on the top of the delta front. Consequently, the main nourishment of the prodelta does not occur directly during and/or immediately after a flood event, but is delayed by sediment being temporarily trapped on the delta front.
Marine Geology (0025-3227) (Elsevier), 2006-12 , Vol. 234 , N. 1-4 , P. 159-177

Droits : 2006 Elsevier B.V. All rights reserved
http://archimer.ifremer.fr/doc/2006/publication-2304.pdf
DOI:10.1016/j.margeo.2006.09.025
http://archimer.ifremer.fr/doc/00000/2304/

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
In Taiwan, about one third of the lithospheric plate convergence between Eurasia and the Philippine Sea plate is accommodated on the eastern coast across the narrow Longitudinal Valley (LV). The Longitudinal Valley Fault (LVF) is the main seismically active fault zone in this region. However, the spatial distribution of ground deformation due to interseismic loading on locked fault segments remains widely unknown. To address this problem, we use a "permanent scatterer" (PS) interferometric synthetic aperture radar (InSAR) approach for processing the ERS satellite archives. The PS mean velocity maps allow accurately mapping and quantifying the ground deformation all along the LV. Assuming that, close to the surface, the fault plane along the central LVF creeping segment dips 55 degrees to the east, we derive a slip vector at the surface of similar to 25 mm/yr with a mean rake of 70 degrees. In agreement with our PS observations, shallow seismicity indicates a clear change in the fault mechanical behavior of the creeping segment around Fuli town. Finally, we propose a combination of the PS velocity fields for estimating a 3-D map of ground deformation. In the southern part of the LV, the vertical component reveals an uplift of the Coastal Range with respect to the LV of similar to 10 mm/yr. Moreover, between Taitung and Luyeh, the vertical deformation is essentially accommodated along the Luyeh Strand. Finally, north of Rueisuei, the Coastal Range uniformly subsides at similar to 15 mm/yr relative to the western side of the LV. However, a local uplift pattern is detected around latitude 23 degrees 42'.
ISSN: 0148-0227

hal-00595532
https://hal.archives-ouvertes.fr/hal-00595532
DOI : 10.1029/2010JB007898

Éditeur(s) : HAL CCSD
Résumé : The Manche-à-Eau lagoon, brackish water ecosystem is subject to tide, trade winds and hurricanes. The 2004 map (IGN) is covered of a 90 m aside square, to place 37 spots in a GIS and to limit them on the field with a GPS. From aerial photos, the outlines drawing allows morphological follow up since 1950. Depth is measured at 1437 spots with bathymetric perch and prob. Stream direction is established during stream and ebb tide using ribbon fixed to the spot and a compass. Water volumes at low and high tide allow calculating the water renewal rate, at each tide. The mapping follow-up shows outlines and island stabilization because of the “shield effect” and soil (root peat), small islands aggregation/disaggregation depending of hurricanes passing. The present bathymetry shows the lagoon filling and the channels digging. General streams are subject to trade-winds (SSE-NNW) andthe tide movement to and fro. The up and down water generates a stream channel situated along the outlines and around dips and sandbanks. Water renewal volume (14.8 %) at each tide, combined with an active and various hydrodynamism tends to improve the water quality in this system.
Evolución Morfológica de la Laguna del Manglar Manche-à-EAU (Guadalupe, Antilles Francesas) de 1950 a 2004, y su batimetría eb 2007La laguna del Manche-à-Eau, ecosistema de agua salobre está sometido a la marea, a los alisios y a los huracanes. El mapa IGN de 2004 está dividido según una malla de 90 m para colocar 37 puntos en un SIG y limitarlos in situ con un GPS. Según las fotografías aéreas, el dibujo de los contornos hace posible el seguimiento morfológico desde 1950. La profundidad se mide en 1437 puntos con una pértiga y una sonda batimétrica. La orientación de las corrientes se establece en el mar y en el reflujo con catavientos fijados en los puntos, y una brújula. Las masas de agua entrantes y salientes permiten el cálculo del volumen de agua renovado durante cada marea. El seguimiento cartográfico muestra una estabilización de los contornos y de la isla debido al “efecto de escudo” y al suelo (turba de raíz), y una agregación/desagregación de los islotes según el paso de los huracanes. De acuerdo a la batimetría actual, se constatan el relleno de la laguna y la excavación de los canales. Las corrientes generales son controladas en superficie por los alisios, vientos de SSE-NNO y por el vaivén de la marea. Los movimientos ascendentes y descendentes de agua generan corrientes profundas a lo largo de los bordes y alrededor de depresiones y bajos. El volumen de agua renovado durante cada marea (14,8%) combinado al hidrodinamismo activo y variado tiende a vivificar este ecosistema.
La lagune de la Manche-à-Eau, écosystème d’eau saumâtre est soumis à la marée, aux alizés et aux ouragans. La carte IGN de 2004 est quadrillée selon une maille de 90 m pour placer 37 points dans un SIG et les borner sur le terrain avec un GPS. D’après les photographies aériennes, le dessin des contours rend possible le suivi morphologique depuis 1950. La profondeur est mesurée à 1437 points avec une perche et une sonde bathymétrique. L’orientation des courants est établie au flot et au jusant avec des penons fixés aux points, et une boussole. Les masses d’eau entrantes et sortantes permettent le calcul du volume d’eau renouvelé à chaque marée. Le suivi cartographique montre, une stabilisation des contours et de l’île due à « l’effet bouclier » et au sol (tourbe racinaire), et une agrégation/désagrégation des îlots selon le passage des ouragans. D’après la bathymétrie actuelle, le comblement de la lagune et le creusement des chenaux sont constatés. Les courants généraux sont gouvernés en surface par les alizés, vent de SSE-NNO et par le va-et-vient de la marée. Les descentes et remontées d’eau obligent ceux-ci à emprunter en profondeur les passages situés le long des berges et autour des dépressions et des hauts-fonds. Le volume d’eau renouvelé à chaque marée (14,8 %) combiné à l’hydrodynamisme actif et varié tend à vivifier cet écosystème.
Proceedings of the 61st Gulf and Caribbean fisheries institute
Le Gosier, Guadeloupe, France

hal-01600092
https://hal.archives-ouvertes.fr/hal-01600092
PRODINRA : 384819

Éditeur(s) : HAL CCSD Blackwell Publishing
Résumé : International audience
Differentiating between forced regressive deposits from deglacial periods inhigh latitude domains and forced regressive deposits from the onset of glacialperiods in low latitude domains is fundamental for the accurate interpretationof glacial cycles within the geological record and then for thereconstruction of palaeogeography and palaeo-climate. A forced regressivedeglacial sequence is documented from the Lake Saint-Jean basin (Quebec,Canada). In this area, the Late Pleistocene to Holocene sediments haverecorded the Laurentide ice sheet retreat accompanied by the invasion ofmarine waters (Laflamme Gulf) from ca 129 cal kyr BP. Subsequently, fluviodeltaicand coastal prograding wedges were deposited; they followed thebase-level fall due to glacio-isostatic rebound. This succession, representinga transition from glacial to post-glacial periods within a previously glaciatedarea, was investigated through recent mapping, preserved landforms, faciesanalysis, and new optical stimulated luminescence and radiocarbon dates.Three basin-scale geological sections share a common lower part made ofisolated ice-contact fan deposits overlying bedrock. Throughout the entirebasin, ice-contact fans are capped by glacimarine muds. Above, fluvial andcoastal prograding systems were deposited and evolved through four steps:(i) deltaic systems progressively increased in width; (ii) coastal influence onsedimentation increased; (iii) hydrographic drainage systems became moreorganised; and (iv) deltas graded from steep (Gilbert delta) to low-angle foresets(mouth-bar delta). Deposited during the base-level fall from glacioisostaticrebound, the complete succession has been designated as a singlefalling stage system tract referred to as a deglacial falling stage system tract.It is representative of a deglaciation sequence in areas previously covered byice during glacial periods (i.e. medium to high latitude domains). Diagnosticcriteria are provided to identify such a deglacial falling stage system tract inthe geological record, which may aid identification of previously unknownglacial cycles.
ISSN: 1469-3496

insu-01184731
https://hal-insu.archives-ouvertes.fr/insu-01184731
DOI : 10.1111/sed.12196

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Recent sedimentary facies and processes along the offshore slope of east Taiwan are investigated using a large set of geophysical and sedimentological data. The Taiwan orogen is often considered as one of the most tectonically active regions in the world and also suffers important climatic activity with an average of four typhoons per year. We have mapped in details the morphosedimentary features and characterized the sedimentary facies along offshore eastern Taiwan. There, we show that the slope is driven by a variety of erosional processes from mass wasting to turbidity current. Mass movements such as slides or mass transport deposits (MTDs) are ubiquitous and affect the whole east coast off Taiwan. Detailed core investigations, such as grain size analysis, chemical and mineralogical composition, revealed that turbidite facies range from thin fine-grained turbidites to thick massive turbidite facies. The detailed analysis of turbidite beds allow us to discuss the controlling factors of turbidity current generation. Turbidity currents represent an important sedimentary process that governs the slope morphology off east Taiwan. Triggering mechanisms likely range from slope instabilities related to earthquakes shaking to failure relative to climatic-controlled pulses of sediment supply. We propose that at least two end-members are characteristics in our turbidite records in term of controlling factor:1) Turbidity currents likely generated by tectonic activity and earthquakes shaking in particular; and2) Turbidity currents likely generated by climatic activity such as typhoon-induced floods.
ISSN: 0025-3227

hal-01277768
https://hal.archives-ouvertes.fr/hal-01277768
DOI : 10.1016/j.margeo.2015.05.013

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : L'objet de cette communication est la caractérisation hydrodynamique d'un système double de barres festonnées en milieu microtidal. Pour comprendre l'évolution du littoral de Leucate-Plage (Languedoc-Roussillon, France), une campagne de mesures hydrodynamiques in-situ a été réalisée, puis complétée par une étude à l'aide du modèle numérique Quasi-3D SHORECIRC de la houle et des courants dans des conditions plus dynamiques non observées. Les mesures in-situ ont permis de réaliser des cartes de circulation hydrodynamique. Les données modélisées donnent des résultats proches de la réalité en terme d'intensité dans la zone de déferlement, en termes de direction et d'intensité dans la zone deshoaling. This paper deals with the hydrodynamic study of a microtidal double crescentic bars system. To understand the coastal evolution of Leucate-Plage (Languedoc- Roussillon, France), a hydrodynamic survey has been realized, added to numerical studies with Q-3D SHORECIRC model for more dynamic unobserved conditions. Hydrodynamic maps with observed data have been produced. The numeric hydrodynamic maps show good analogies in the shoaling zone but some difference in the surf zone.
ISSN: 1760-8716

hal-00854013
https://hal.archives-ouvertes.fr/hal-00854013
DOI : 10.5150/jngcgc.2008.007-F

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We analyze in this study a new set of marine data including 3D local tomography, 1992-2008 relocated earthquakes and two recent multichannel seismic lines to characterize the deformation style in the collision area offshore east Taiwan. We have mapped in detail the Mohos of the converging plates as well as the subduction interface with a resolution never reached before. We show that the sharp continental subduction of the Eurasia plate, beneath the middle part of the Central Range, indents the Philippine Sea plate (PSP) as attested by intra-oceanic slicing and incipient subduction of the PSP beneath the east coast of Taiwan. The westernmost part of the PSP slab is probably experiencing a beginning of break-off as attested by NW-trending en-échelon shear zones beneath the southern slope of the southern Ryukyu arc (SRA). These en-échelon shear zones have a sinistral component favored by the "collision-free" subduction of the PSP north of 24°30′N. The down-faulting of the subduction interface forms ramps along which earthquakes clusterize. Three M7 subduction earthquakes occurred offshore Suao city along these ramps with a recurrence interval of about 40 years: 1920 Mw7.7, 1963 Mw7.2 and 2002 Mw7.1 events. The 1966 Mw6.0-7.5 earthquakes sequence likely outlines a WNW-ESE left-lateral intra-slab shear zone. The SRA upper plate accommodates the complex geometry and deformation of the subducting PSP through seismic deformation. Shallow high velocities fringing the Luzon volcanic arc (LVA) beneath the Longitudinal Valley and north of the southernmost Ryukyu forearc basins are interpreted as relics of the LVA forearc basement squeezed in the collision zone. Based on the accommodation of a large part of the convergence through shortening within the PSP and the subsequent segmentation of the shallow subduction interface, we consider that the nucleation of a Mw ≥ 8 earthquake along the southernmost Ryukyu megathrust is unlikely.
ISSN: 0040-1951

hal-00853365
https://hal.archives-ouvertes.fr/hal-00853365
https://hal.archives-ouvertes.fr/hal-00853365/document
https://hal.archives-ouvertes.fr/hal-00853365/file/publallemandifremer.pdf
DOI : 10.1016/j.tecto.2013.03.020

Éditeur(s) : IEEE
Résumé : Bathymetric estimation using remote sensing images has previously been applied to high spatial resolution imagery such as CASI, Ikonos, or SPOT but not on medium spatial resolution images (i.e., MERIS). This choice can be justified when there is a need to map the bathymetry on large areas. In this letter, we present the results of the bathymetry estimation over a large known area, the Gulf of Lion (France), expanding over 270 x 180 km.
Geoscience and Remote Sensing Letters, IEEE (1545-598X) (IEEE), 2007-04 , Vol. 4 , N. 2 , P. 274-277

Droits : 2007 IEEE
http://archimer.ifremer.fr/doc/2007/publication-2597.pdf
DOI:10.1109/LGRS.2007.890548
http://archimer.ifremer.fr/doc/00000/2597/

Éditeur(s) : HAL CCSD Coastal Education and Research Foundation
Résumé : The south part nearshore zone of the Gulf of Lions coast (Mediterranean Sea) is characterized by a double crescentic sandbar system. During the winter 2007, a campaign of intensive hydrodynamical measurements (current profiles) was realized. During this campaign, based mainly on ADCPs, the maximal recorded wave height was 1.5 m. Four events were observed; two of those had northern incidence, one with southern incidence and a last one with frontal incidence. This paper proposes 3D hydrodynamical circulation maps over this microtidal bar system. The currents described reveals rip, bed-return and longshore currents strongly influenced by the wind-waves forcing and the bathymetry. At the apex of the oblique incidence events, the longshore component is the most important. The breaker zone is only located over the inner bar. During storm waning conditions, the cross-shore currents appear over the trough of the outer bar. The hydrodynamic circulation is then compared with other observations made in the literature.
ISSN: 0749-0208
Szczecin, Poland

hal-00767593
https://hal.archives-ouvertes.fr/hal-00767593

Éditeur(s) : Centre français du littoral
Résumé : This study presents the first results of an ongoing research program that aims to derive thematic maps of the intertidal lagoon of Arcachon (SW Atlantic coast of France) from space imagery. At this stage, we present the results of the tests performed on Formosat-2 imagery. Several classification strategies have been tried with the aim to discriminate the sedimentary facies and the main species of the lagoon. The classes calculated by an optimized unsupervised clustering method, based on simulated annealing global minimization technique, were used to train a supervised classification algorithm. This approach allowed us to derive a bio-sedimentary map which overall accuracy is about 84%. Also, this method has the advantage of describing the fraction of vegetation cover of the seagrass.
Cette étude présente les premiers résultats d’un vaste programme de recherche qui ambitionne de définir une méthode de cartographie des platiers intertidaux du Bassin d’Arcachon (France) par télédétection. Les résultats présentés ici concernent les tests effectués sur l’imagerie Formosat-2 dans le but de discriminer les sédiments et les principales espèces végétales de la lagune. Le résultat d'une classification non supervisée optimisée par la méthode du recuit simulé est ensuite utilisé pour entraîner une classification par minimum de distance. Cette approche permet d’obtenir une carte des faciès bio-sédimentaires dont la précision est estimée à plus de 84 %. Cette méthode présente, en outre, un excellent potentiel pour la détermination du pourcentage de couvert végétal des herbiers à zostères.
Paralia (1760-8716) (Centre français du littoral), 2008 , N. 10 , P. 563-572

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00254/36572/35110.pdf
DOI:10.5150/jngcgc.2008.054-L
http://archimer.ifremer.fr/doc/00254/36572/

Éditeur(s) : HAL CCSD Société nationale de protection de la nature
Résumé : International audience
The island of Moorea in French Polynesia is representative of a relatively well preserved small tropical oceanic island but both its terrestrial and marine ecosystems are currently under strong anthropogenic pressures. The terrestrial ecosystems are facing an increasing urbanization, and the destruction and modification of their natural habitats by cultivation and forestry plantations, accidental or intentional fires, and particularly by the invasion of alien plant and animal species. Coastal areas and reef ecosystems are threatened by shoreline artificialization, sedimentation due to soil erosion, increasing uses of marine and lagoon resources and frequency of coral bleaching events. A significant erosion of terrestrial and marine biodiversity is observed on the island since the last decades. In the context of the Land Management Plan (PGA) and Marine Area Management Plan (PGEM) recently set up in the island by local authorities, scientific surveys and inventories were made in 2006 in order to assess the status of terrestrial biodiversity (vascular plants) and marine biodiversity (reef fishes) and compare areas with different anthropogenic pressures. Studies conducted on the flora and the vegetation at low and middle elevation along altitudinal transects show that the plant invasion process is related to climatic and topographic factors, and species autoecology. The marine study aims to compare the protected areas with control areas in order to test the effectiveness of protection measures and to propose a streamlined monitoring protocol. A methodological study in both terrestrial and marine ecosystems was conducted in order to propose biodiversity indicators which are crucial for decision making in conservation and sustainable development of island biodiversity. We used Geographic Information System (GIS) as a fast and intuitive tool for mapping indicators and their variability. This methodological approach developed on the island of Moorea could be used as a model for other tropical islands
Moorea est une petite île océanique tropicale de la Polynésie française relativement bien préservée, mais dont les écosystèmes terrestres et marins sont actuellement soumis à de fortes pressions anthropiques. Le milieu terrestre est confronté à une urbanisation croissante, à la destruction ou à la modification des habitats naturels pour l’extension des cultures ou des plantations forestières, aux incendies volontaires ou accidentels, et particulièrement à l’invasion d’espèces végétales et animales introduites. Les zones côtières et les récifs coralliens sont menacés par de multiples perturbations telles que l’artificialisation des lignes de rivage, l’apport de sédiments dus à l’érosion des sols, l’augmentation des usages des ressources marines et lagonaires et de la fréquence des phénomènes de blanchissement du corail. Une érosion sensible de la biodiversité terrestre et marine de l’île est observée depuis les dernières décennies. Dans le cadre du Plan Général d’Aménagement (PGA) et du Plan de Gestion de l’Espace Maritime (PGEM) mis en place par les autorités locales, des inventaires scientifiques ont été réalisés en 2006 dans le but d’évaluer l’état de la biodiversité terrestre (plantes vasculaires) et marine (poissons récifaux) et de comparer des zones soumises à différentes perturbations. Les études réalisées sur la flore et la végétation de basse et moyenne altitude le long de transects altitudinaux montrent des processus d’invasion végétale différents en relation avec les facteurs climatiques, topographiques et autoécologiques des espèces. Les études en milieu marin visent à comparer des aires protégées à des aires témoins afin de suivre l’efficacité des mesures de gestion. La réflexion méthodologique menée parallèlement sur les deux écosystèmes a pour but d’illustrer différents indices de biodiversité nécessaires à la prise de décision en matière de conservation ou de développement durable de la biodiversité insulaire et de réaliser un état de référence pour établir un diagnostic sur l’état de la biodiversité. La représentation cartographique des indices à l’aide d’un SIG, illustrée dans cette étude avec la richesse spécifique terrestre et marine, permet une lecture intuitive et rapide de la variabilité de cet indice dont la restitution est basée sur une standardisation du nombre d’espèces. Cette approche méthodologique développée sur l’île de Moorea pourrait servir de modèle pour d’autres îles tropicales
EISSN: 2429-6422

hal-01306285
https://hal-univ-perp.archives-ouvertes.fr/hal-01306285

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In order to better constrain the relationship between tectonics and sedimentation of the Eastern Sardinian Margin, from the Messinian to the present day (METYSS project), a lithostratigraphic study was carried out on the Late Neogene deposits along the Cedrino Valley (eastern Sardinia). The late Neogene evolution is documented from sedimentological and tectonic analysis, biostratigraphic dating, and by mapping and logging stratigraphic sections. Previous authors have differentiated an early Pliocene marine formation from an older continental formation, possibly Miocene, the entire system being covered by late Pliocene to Quaternary lava flows. Preliminary biostratigraphic data suggest the absence of the lowermost Pliocene, based on the absence of Globorotalia margaritae and the presence of Globorotalia puncticulata, implying a sediment age between 3.81 and 2.41 Ma. At the foot of the Fiuli cliff, some mud clasts include a coccolith microflora, Tortonian in age, suggesting reworking. The Pliocene marine deposits consist of a single filling sequence instead of a succession of superimposed sequences as we would expect during this period of time; the occurrences of terms rarely respect the usual transgressive-regressive succession. Contrasting bathymetric environments (fore-shore, pro-delta, shelf or upper slope) can be abruptly superimposed on top of the other, along few meter thick intervals. A rapidly flooded term is observed in several sites and indicates a spatial variability over only a few kilometers distance. Some deep water deposits are in the middle of the infilling Pliocene sequence, whereas shallower water deposits can be repeated along a vertical section, or even interrupted by emersion. These marked differences can express syn-, or possibly post-sedimentation tectonic uplifts. The 10–25° bed dips originated through local tectonic uplift. At Fiuli, the geometry of the bedding planes is indicative of tilting toward the west, in a direction opposite to the one observed at Onifai. These Pliocene series form a wide syncline with an approximately NNE–SSW axis. This morpho-structural behavior appears to be largely atypical of this East-Sardinian coastal area.
ISSN: 1040-6182

hal-01134707
https://hal.archives-ouvertes.fr/hal-01134707
DOI : 10.1016/j.quaint.2014.11.022

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
ISSN: 2072-4292

hal-01429038
https://hal.archives-ouvertes.fr/hal-01429038
DOI : 10.3390/rs5073583