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The Working Group on Fisheries Benthic Impact and Trade-offs (WGFBIT) develops methods and performs assessments to evaluate benthic impact from fisheries at regional scale, while con-sidering fisheries and seabed impact trade-offs. In this report, new fishery benthic impact assessments are carried out for several sub-regions in the Mediterranean (Greek waters, South Adriatic Sea, Sicily waters). For other regions, updates of the whole assessment or specific steps only were presented. A standard advice sheet for the regional benthic assessments, intended as input to the next generation of the ICES Ecosystem and Fisheries Overviews, was finalised and compiled for some regions as example (Greek wa-ters, Baltic Sea). A validation of the longevity relationships using new data was executed for the Kattegat area and the Southern North Sea. In relation to the methodology, some recommenda-tions were formulated concerning the update on depletion rates, the use of epifauna- or infauna-based data, guidance on which set of epibenthic species to include and the time scale for setting the average swept-area-ratio (SAR) used in model fitting and assessment. A benchmarking pro-cess comparing available benthic impact assessment approaches for MSFD descriptor 6 “Seafloor integrity” is needed, as the WGFBIT approach (relative benthic state) is not the only way to assess benthic impacts from physical disturbances. A start was made to explore how to incorporate more explicitly ecosystem functioning in to the WGFBIT seafloor assessment methodology. An improved understanding of the relationships between total community biomass and ecosystem functioning may assist in setting acceptable thresholds for ecosystem impacts from trawling. Furthermore, an improved understanding of the link between species functional effect traits and proxies and processes for specific ecosystem functions could help increase our ability to predict the impact of fishing disturbance on benthic ecosystem functioning more accurately. The ecosys-tem function we focus on is the biogeochemical cycling of organic matter. Two approaches were discussed (i) Biological traits approach focusing on the linkage between biological traits and eco-system functions and (ii) biogeochemical modelling approach using the established the OMEXDIA model. FBIT Published Non Refereed

La docencia presencial de la Univ. Barcelona se apoya en su Campus virtual. Para promover el aprendizaje adaptativo, hemos analizado los Recursos/Actividades (número, tipo y frecuencia de uso) de 3 cohortes del Grado de Ciencias del Mar (30 Informes de actividad en total y 10 Registros de uso seleccionados). Predominan los Recursos (87%), pero se interactúa más en las Actividades. El análisis de los Registros ha permitido relacionar los resultados con el rendimiento, género u opcionalidad.

Mining activities are essential to our society, but ore extraction and treatment produce waste that must be stored in safe places without harm to the environment. For a long time, seafloor disposal has been viewed as a cheap option with barely visible impacts. In Portman Bay, SE of Spain, large amounts of tailings from open pit sulphide mining were discharged directly into the coastal sea over 33 years, thus forming a massive deposit that completely infilled the bay and expanded seawards over the inner continental shelf. Here we present the first multiproxy physicochemical characterization of the submarine tailings in Portman Bay, mostly by using non-destructive techniques, also including pre-dumping and post-dumping sediments. Eight distinct sedimentary facies, grouped in four stratigraphic units, have been thus identified in a set of up to 4.3 m long gravity cores totalling more than 60 m. Geogenic and anthropogenic geochemical proxies consistently allow differentiating pre-dumping sediments from tailings. Potentially toxic metals if made bioavailable can reach high concentrations in units including or formed exclusively by tailings (i.e. up to 3455, 2755 and 1007 mg kg−1 for Pb, As, and Zn, respectively). Some physical properties, such as magnetic susceptibility, are particularly useful as the tailings are rich in Fe-bearing minerals (>30% Fe in some layers). Estimated sedimentation rates show a strong gradient from proximal to distal locations, with rates in excess of 50 cm yr−1 to less than 1 cm yr−1. We ultimately document the history of the transformation of Portman Bay from an almost natural state to a new condition after a long period of massive dumping of mine tailings. Our study provides guidance to further assessments in a context where the diversity of marine environments impacted by the disposal of mine waste is expected to grow in the near future.

La decisió d’emprendre un doctorat no és senzilla. Mentre que la durada i la intensitat de l’esforç necessaris per a assolir-lo es poden determinar raonablement bé, els beneficis professionals que es podrien aconseguir són difícils de conèixer, ja que depenen de les possibilitats d’inserció laboral dels futurs doctors. L’objectiu principal d’aquest article és proporcionar algunes dades sobre les perspectives laborals actuals a Catalunya dels doctorats en les àrees de tecnologies industrials, tecnologies de la informació i la comunicació (TIC), i arquitectura, construcció i enginyeria civil. A partir de les enquestes d’inserció laboral dels doctors que fa l’Agència per a la Qualitat del Sistema Universitari de Catalunya (AQU), l’article s’endinsa, per a cadascuna de les tres àrees esmentades, en el lloc de treball dels doctors, la necessitat de tenir la titulació de doctor per a accedir-hi i per a fer la feina que hi fan, el grau de satisfacció amb els estudis i amb la feina, i la valoració de la decisió de fer el doctorat que van prendre en el seu moment. Les dades que es presenten poden ser útils per als graduats que estiguin valorant seguir un doctorat en les àrees indicades. També poden interessar als responsables dels programes de doctorat, de cara a decidir l’orientació de la recerca que es duu a terme i el contingut de la formació associada. The decision to pursue a doctorate is not an easy one. While the duration and intensity of the effort required to achieve it can be reasonably conceived, the professional benefits that may be achieved are difficult to determine beforehand, as they depend on the employment opportunities of the future doctoral degree holders. This paper seeks to illustrate current job prospects in Catalonia for doctorate holders in the areas of industrial technologies, ICTs, architecture, construction, and civil engineering. Based on the surveys on access to the labour market for doctors carried out by the Catalan University Quality Assurance Agency (AQU Catalunya), for each of the three areas we delve into the workplace of doctoral degree holders, the reasons why a doctorate is needed to access it and to perform the associated tasks, the degree of satisfaction of doctorate holders with their studies and position, and the evaluation of their decision to take a doctorate. The information presented here may be useful for graduates who consider taking a doctorate in the above-mentioned areas. It may also be of interest to doctoral program managers, allowing them to prioritize the orientation of research in their programs and to better define the contents of the associated training.

This study presents the reconstructed evolution of sea surface conditions in the central-western Mediterranean Sea during the late Holocene (2700 years) from a set of multi-proxy records as measured on five short sediment cores from two sites north of Minorca (cores MINMC06 and HER-MC-MR3). Sea surface temperatures (SSTs) from alkenones and Globigerina bulloides Mg / Ca ratios are combined with δ18O measurements in order to reconstruct changes in the regional evaporation–precipitation (E–P) balance. We also revisit the G. bulloides Mg / Ca–SST calibration and re-adjusted it based on a set of core-top measurements from the western Mediterranean Sea. Modern regional oceanographic data indicate that Globigerina bulloides Mg / Ca is mainly controlled by seasonal spring SST conditions, related to the April–May primary productivity bloom in the region. In contrast, the alkenone–SST signal represents an integration of the annual signal. The construction of a robust chronological framework in the region allows for the synchronization of the different core sites and the construction of “stacked” proxy records in order to identify the most significant climatic variability patterns. The warmest sustained period occurred during the Roman Period (RP), which was immediately followed by a general cooling trend interrupted by several centennial-scale oscillations. We propose that this general cooling trend could be controlled by changes in the annual mean insolation. Even though some particularly warm SST intervals took place during the Medieval Climate Anomaly (MCA), the Little Ice Age (LIA) was markedly unstable, with some very cold SST events mostly during its second half. Finally, proxy records for the last centuries suggest that relatively low E–P ratios and cold SSTs dominated during negative North Atlantic Oscillation (NAO) phases, although SSTs seem to present a positive connection with the Atlantic Multidecadal Oscillation (AMO) index.

Here we present a synthesis of bedforms and sediment types on the shelves surrounding the Iberian Peninsula and the Balearic Islands, after the integration several pieces of bathymetric, morphological and sedimentological datasets. The Iberian and Balearic shelves are divided into segments according to the largescale margin configuration, fluvial sediment supply and hydrodynamic regime. Their geological settings and large-scale sedimentation patterns place the investigated shelves into two broad categories: abrupt, steep and narrow sediment-starved shelves, illustrated by the Cantabrian shelf, and gentle, smooth and wide sediment- fed shelves, such as the shelves off some major flivial systems. An in-depth classification was subsequently attempted, based on morpho-sedimentary types. Under this approach, the Iberian and Balearic shelves can be classified as: (1) storm-dominated shelves, with erosional rocky floors, frequent abrasion surfaces and coarse-grained sediments; (2) current-dominated shelves, showing a good equilibriumbetween sediment fluxes and coastal and shallow ocean circulation, with laterally extensive muddy belts; (3) sediment supply-dominated shelves, where extensive subaqueous deltas develop off river mouths; and (4) wave-dominated shelves that occur off coastal stretches with minor and/or multiple fluvial sediment sources and enhanced littoral current.

Sediment sequences are the most valuable record of long-term environmental conditions at local, regional and/or global scales. Consequently, they are amongst the best archives of the climatic and oceanographic history of the Earth. In the last few decades a strong effort has been made, both in terms of quantity and quality, to improve our knowledge regarding the evolution of our planet from marine and lake sediment records, and also from other records such as ice cores. Such an effort requires reinforcing the geographical coverage and achieving the highest possible robustness in the reconstruction of past environments. Such a target requires the optimization of the time resolution of the records and reconstructions so that fast, high frequency shifts, such as those occurring nowadays due to the on-going global warming, can be disentangled. Beyond paleoenvironmental research, other disciplines have also contributed significantly to the fast growing number of sediment cores already available worldwide. Knowing the physical state and the chemical composition of sedimentary deposits is essential for land management purposes and for many industrial applications. A number of key technological developments are now allowing the acquisition for the first time of massive amounts of multiple parameters from sediment cores in a non-destructive, fast, continuous, repetitive and high-resolution form. In this paper we provide an overview of the state-of-the-art continuous and non-destructive analytical techniques used by the geoscientific community for the study of sediment cores and we present some examples of the application of these methods in several studies carried out around the Iberian Margin.

El sondeo PRGL1-4, recuperado en el talud superior, ha proporcionado un registro único, continuo y de larga duración para la investigación del impacto de las oscilaciones del nivel del mar de escala glacial/interglacial durante el Pleistoceno Superior en la construcción del margen continental del Golfo de León, dominado por aportaciones sedimentarias de origen fluvial. El estudio en detalle de los cambios del tamaño de grano y la composición elemental del sedimento, junto con una robusta cronoestratigrafía basada en el registro de isótopos de oxígeno en foraminíferos planctónicos, ha permitido reinterpretar la sismoestratigrafia del margen para los últimos 530 ka. El sondeo PRGL1-4 comprende el apilamiento formado por cinco unidades depositadas durante las bajadas del nivel del mar de los últimos cinco ciclos glacial/interglacial de 100 ka. La extensa plataforma del Golfo de León ha jugado un papel determinante en el desarrollo del margen profundo puesto que las oscilaciones del nivel del mar, además de modificar el espacio de acomodación, influyeron directamente en cambios cíclicos del modelo deposicional a través de la activación y desactivación de procesos con gran capacidad erosiva y de transporte de sedimento más allá de la plataforma. El registro del sondeo PRGL1-4 también muestra el impacto de las oscilaciones del nivel del mar a escala milenaria durante el MIS 3, con evidencias claras de la ocurrencia de niveles del mar altos durante la fase inicial de todos y cada uno de los interestadios cálidos de los ciclos de Dansgaard-Oeschger. El registro PRGL1-4 supone, por tanto, la primera evidencia de un acoplamiento consistente entre las oscilaciones del nivel del mar y la variabilidad climática rápida de escala milenaria asociada a los ciclos de Dansgaard-Oeschger.

We show the results provided by piezocone tests in determining the stratigraphic profile and the soil classification of two drilling sites in the outer shelf and the upper slope of the Gulf of Lion, PRGL2 and PRGL1, respectively. Correlations with grain-size data indicate that sleeve friction can be used for profiling fine-grained sediments (site PRGL1), whereas cone tip resistance is the most adequate for sequences made of alternations of coarse- and fine-grained intervals (site PRGL2). Normalized cone resistance and friction ratio proved to be also appropriate for soil stratigraphy as it depicts trends in the coarse fraction of the tested soil. Silts and clays present in similar proportions at site PRGL1 responded to piezocone testing as pure clays usually do. Consequently, classical soil classification methods resulted in erroneous interpretation of these sediments as clays, whereas classification of the heterogeneous deposits at PRGL2 was consistent with the grain size. When tied to a high-resolution seismic reflection profile, the stratigraphy interpreted from the piezocone profile matches with the main seismic sequences and discontinuities defined from seismic stratigraphy analysis. Graded bedding also matches with cone tip resistance and sleeve friction data.

The eastern Mediterranean sapropels are amongst the most intensively investigated phenomena in the palaeoceanographic record , but relatively little has been written regarding the origin of the equivalent of the sapropels in the western Mediterranean, the Organic Rich Layers (ORL's). ORL's are recognised as sediment layers containing enhanced Total Organic Carbon that extend throughout the deep basins of the Western Mediterranean, and are associated with enhanced total barium concentration and a reduced diversity (dysoxic but not anoxic) benthic foraminiferal assemblage. Consequently, it has been suggested that ORL's represent periods of enhanced productivity coupled with reduced deep ventilation, presumably related to increased continental runoff, in close analogy to the sapropels. We demonstrate that despite their superficial similarity, the timing of the deposition of the most recent 1 ORL in the Alboran Sea is different to that of the approximately coincident sapropel, indicating that there are important differences between their modes of formation. We go on to demonstrate, through physical arguments, that a likely explanation for the origin of the Alboran ORLs lies in the response of the Western Mediterranean basin to a strong reduction in surface water density and a shoaling of the interface between intermediate and deep water during the deglacial period. Furthermore, we provide evidence that deep convection had already slowed by the time of Heinrich Event 1, and explore this event as a potential agent for preconditioning deep convection collapse. Important differences between Heinrich-like and deglacial-like influences are highlighted, giving new insights into the response of the western Mediterranean system to external forcing.

The detailed analysis of the International Marine Past Global Changes Study core MD99-2343 recovered from a sediment drift at 2391 m water depth north of the island of Minorca illustrates the effects of climate variability on thermohaline circulation in the western Mediterranean during the last 12 kyr. Geochemical ratios associated with terrigenous input resulted in the identification of four phases representing different climatic and deepwater overturning conditions in the Western Mediterranean Basin during the Holocene. Superimposed on the general trend, eight centennial- to millennial-scale abrupt events appear consistently in both grain size and geochemical records, which supports the occurrence of episodes of deepwater overturning reinforcement in the Western Mediterranean Basin. The observed periodicity for these abrupt events is in agreement with the previously defined Holocene cooling events of the North Atlantic region, thus supporting a strong Atlantic-Mediterranean climatic link at high-frequency time intervals during the last 12 kyr. The rapid response of the Mediterranean thermohaline circulation to climate change in the North Atlantic stresses the importance of atmospheric teleconnections in transferring climate variability from high latitudes to midlatitudes.

Els sediments marins són un dels millors arxius dels canvis climàtics del passat pel seu caràcter essencialment continu i pel fet que datar-los és relativament senzill. En les darreres dècades, molts estudis paleoclimàtics s'han centrat en els anomenats «canvis climàtics abruptes», els quals hom pot prendre com a anàlegs dels canvis que poden produir-se en el futur. Un dels punts clau és el paper de l'atmosfera en el desfermament i la transferència dels canvis climàtics abruptes. En aquest marc, investigar la influència de les partícules de pols eòlica sobre el clima mereix una atenció especial. L'estudi de l'acumulació de pols eòlica en els sediments marins esdevé, doncs, crucial, no només per a entendre els canvis del passat sinó també per a explicar els mecanismes del canvi climàtic. En aquest article, hom presenta les interaccions entre la pols atmosfèrica i el canvi climàtic ràpid a partir de l'estudi del registre sedimentari marí profund aigües enfora de l'Àfrica nord-occidental i del mar d'Alboran a dues escales temporals, la glacial-interglacial i la mil·lenària., Marine sediments are one of the best archives of past climate change since they are essentially continuous in character and their age can be determined relatively easily. During the last few decades, many paleoclimatic studies have focused on abrupt climate changes, which could be used as models of future climate changes. One of the key questions to be answered is the role of the atmosphere in triggering and transferring abrupt climate changes. In this respect, investigating the influence of eolian dust particles on climate change deserves special attention. The study of eolian dust accumulation in marine sediments is crucial not only to understand past climate change but also to explain the mechanisms of climate change in general. In this article, interactions among dust in the atmosphere and rapid climate change are discussed after a review of marine sediment records, at the glacial-interglacial and millennial temporal scales, from off the coast of Northwest Africa and the Alboran Sea.

bulk element composition and grain-size distribution to characterize the temporal evolution of the terrigenous input to this area throughout the last 50 ka. The high-resolution elementary profiles show high frequency oscillations, particularly of Si, Ti and K contents, associated with terrigenous input variability. These fluctuations mark significant changes in the source areas and/or in the nature of transport and sedimentation processes most likely related to abrupt changes in oceanographic and atmospheric conditions. The Menorca core records were compared with the geochemical results of a previously studied core from the Alboran Sea, from where it became obvious a similar behaviour in some of the terrigeneous elements at both core locations. The obtained records vary with a clear Dansgaard-Oeschger periodicity reaching higher values during the North Atlantic's Heinrich Events. These results evidence the presence of a millennial-scale synchronous pattern in the Western Mediterranean in terms of deposition of terrigenous material. In addition, grain-size analyses of Menorca core reveal rhythmic episodes of coarser particle inputs during the Holocene likely related to shifts in the intensity of deep-water currents.

This paper provides a spatial and temporal multi-scale approach of European submarine canyons. We fi rst present the long-term geologic view of European margins as related to controls on submarine canyon development. Then we discuss the extent to which submarine canyon systems resemble river systems because both essentially form drainage networks. Finally, we deal with the hortest-term, highestresolution scale to get a fl avor of the current functioning and health of modern submarine canyons in the northwestern Mediterranean Sea. Submarine canyons are unique features of the seafl oor whose existence was known by European fi shermen centuries ago, especially for those canyons that have their heads at short distance from shoreline. Popular names given to specifi c canyons in the different languages spoken in European coastal communities refer to the concepts of a"deep" or"trench." In the old times it was also common thinking that submarine canyons where so deep that nobody could measure their depth or even that they had no bottom. Submarine canyons are just one of the seven different types of seafl oor valleys identifi ed by Shepard (1973) in his pioneering morphogenetic classifi cation. Shepard (1973) defined submarine canyons as"steep-walled, sinuous valleys, with V-shaped cross sections, and relief comparable even to the largest of land canyons; tributaries are found in most of the canyons and rock outcrops abound on their walls." Canyons are features typical of continental slopes with their upper reaches and heads cut into the continental shelf.

Sea-floor bathymetric and backscatter data is used to image one of the youngest major landslides in the Northwestern Mediterranean Sea. The landslide, a 26 km3 debris flow, covers 2,000 km2 of the Ebro continental slope and base-of-slope offshore Spain. A pattern of low backscatter large sediment blocks which moved downlope while keeping their internal coherence separated by topographically low high backscatter lineations of coarse sediment is shown in the sea-floor images. The results of the interpretation of these features provide fundamental insights on the behaviour of submarine debris flows from which hydrocarbon search could greatly benefit.

Results from sedimentological and mass-physical properties of seven piston cores recovered on the youngest major landslide in the Ebro continental slope and base-of-slope, Northwestern Mediterranean Sea, are presented.

Special isssue Dorsales Oceánicas - Oceanic Ridges.-- 5 pages, Con este vocabulario inglés-castellano y castellano-inglés se pretende a la vez ampliar y cohesionar la terminología en Geociencias Marinas en lengua castellana. Se incluyen los términos más frecuentemente utilizados en la investigación de dorsales oceánicas y, dentro de un marco más amplio, en Tectónica de Placas

Special isssue Dorsales Oceánicas - Oceanic Ridges.-- 9 pages, En la presente recopilación se recogen un buen número de títulos significativos acerca de las dorsales oceánicas. [...]

La Dorsal Sur de Scotia (DSS) constituye une frontera de placas transformante con sentido senestral, que limita las placas de Scotia, al norte, y Antártica, al sur. Durante la campaña de geología y geofísica marinas 'Scotia 92', realizada en Febrero de 1992 a bordo del BIO Hespérides, se ha estudiado su extremo occidental y sectores próximos a la Cuenca de Bransfield, entre el margen nor-occidental de la Península Antártica y las islas Shetland del Sur, Elefante y Orcadas del Sur. Al norte y sur de la DSS se desarrollan las cuencas de Scotia y de Powell, respectivamente. Los datos de sísmica de multicanal, magnetismo y gravimetna obtenidos muestran caracteristicas diferenciales entre ambas cuencas. La morfoestructura de la DSS, formada por dos crestas paralelas separadas por una profunda depresión axial, ha sido recubierta mediante perfilaje de multihaz con el sistema SIMRAD EM-12 en una área de 50 x 100 km. La batimetría resultante ha permitido reconocer en detalle las caracteristicas de una depresión de más de 5.300 m de profundidad y de 10 a 30 km de anchura, bautizada como Fosa Hespérides. En ella se aprecia la existencia de dos famílias de lineaciones, la primera de dirección E-W y paralela al límite de placas, y la segunda de dirección NW-SE. La primera acomodaría el movimiento cizallante regional mientras que la segunda estaría asociada con una componente extensional probablemente relacionada con la dirección de la Cuenca de Bransfield. La forma romboédrica de la fosa está determinada por la interacción de ambas famílias de lineaciones. Teniendo en cuenta que el límite de placas transcurre entre las dos crestas, interpretamos la Fosa Hespérides como una cuenca de pull-apart desarrollada como consecuencia del movimiento de cizalla a lo largo de la DSS.

Special isssue Dorsales Oceánicas - Oceanic Ridges.-- 10 pages, 7 figures, [EN] The North Fiji Basin is a complex marginal basin formed 10 Ma ago. It is located in the south-west Pacific, on the border of the Pacific and Indo-Australian crustal plates, between two subduction zones of opposed polarity: the New Hebndes trench, to the west, and the Tonga- Kennadec trench, to the east. The North Fiji Basin contains, on a small scale, many of the essential components of global plate tectonics: fracture zones, active spreading ridges, and triple junctions. In the center of the North Fiji Basin, there is a spreading axis constituted of three separate branches which can be individualized in accordance to their dominant directions. One of them, the N160 segment, is discussed in detail in this article, mainly based on recent data sets obtained during the Yokosuka 90 cruise (STARMER project, managed by the IFREMER, France, and the Science and Technology Agency, Japan). The aim of this cruise, carried out between 10th January and 6th February 1991, was the geological and geophysical study of the N160 section of the North Fiji Basin Ridge. Specific features of the N160 segment are pointed out which make it especially interesting with regard to the general knowledge and hypotheses about oceanic spreading ridges. As an example, the N160 segment shows an intermediate spreading rate of 5 cm/a and, at the same time, has a morphology which should be considered as being typical of slow-spreading centers. A succession of en échelon alternating rises and grabens exists between the two triple junctions limiting the segment, the northern one belonging to the Ridge-Ridge-Ridge (RRR) type, and the southern one to the Ridge-Ridge-Fracture Zone (RRF) type. The entire N160 segment is an extremely young morphostructural feature which, according to recorded magnetic stripes, began to be active less than one million years ago as a result of a rapid volcano-tectonic event, [ES] La campaña oceanográfica franco-japonesa Yokosuka 90, llevada a cabo del 10 de Enero al 6 de Febrero de 1991, tuvo por objeto el estudio geológico y geofísico del segmento de segundo orden o ramal de dirección N160 de la dorsal de la Cuenca Nor-Fidjiana (Pacífico sudo- este). Este ramal es especialmente interesante, no sólo por estar situado en una cuenca de tras-arco, sino también en el marco de las hipótesis que intentan establecer las relaciones entre tasas de expansión y morfoestructura en las dorsales oceánicas. Así, en el ramal estudiado coinciden una tasa de expansión intermedia (5 cm/a) y una morfología típica de dorsal lenta. Dicho ramal, segmentado y constituido por una sucesión de crestas y de grabens desplazados lateralmente, se sitúa entre dos puntos mples, uno de tipo dorsal-dorsal-zona de fractura (RRF), al sur, y otro, de tipo dorsal-dorsal-dorsal (RRR), al norte. El ramal N160 de la Cuenca Nor-Fidjiana es, por otra parte, extremada- mente joven ya que de acuerdo con las anomalías magnéticas se habría formado durante un episodio volcano-tectónico iniciado hace menos de 1 Ma

Esta Tesis parte de un doble planteamiento: estudio temático de los diferentes tipos de deslizamientos submarinos, y estudio regional de la evolución morfo-sedimentaria del talud y el glacis continentales del Golfo de León. Está dividida en tres partes bien definidas, más las conclusiones: 1) Una parte bibliográfica exhaustiva acerca de los deslizamientos submarinos en los márgenes continentales del mundo; 2) Una parte dedicada al análisis detallado de las características del recubrimiento sedimentario reciente del Golfo de León. Para ello se han confeccionado mapas de isópacas, isócronas, isócoras y morfo-interpretativos, así como diversos tipos de perfiles y esquemas que permiten seguir la evolución morfo-sedimentaria reciente del area. Se ha hecho especial hincapié en los procesos y estructuras de desestabilización del recubrimiento sedimentario; y 3) Una parte en la que se analiza la movilidad de las evaporitas mesinienses y su influencia determinante en la evolución morfo-sedimentaria del talud y el glacis durante el Plio-Cuaternario. En esta parte se presenta el modelo evolutivo a que hemos llegado. Complementan el cuerpo de la Tesis dos Anexos en los que se tratan temas metodológicos y otros aspectos que, aún sin haber aportado los resultados apetecidos de cara al planteamiento inicial de la Tesis, consideramos que pueden interesar a algunos lectores, particularmente a los que desarrollan sus investigaciones en el Mediterráneo occidental. Completa la Tesis el inexcusable e imprescindible capítulo bibliográfico.

El sistema deposicional del Golfo de León presenta una plataforma constituida por varios prismas epicontinentales, un talud y unascenso continental entallados por numerosos cañones, y dos cuerpos deposicionales profundos de gran importancia: el abanico del Ródano y el «Acúmulo de los Cañones Pirenaicos)). Las evaporitas messinienses han jugado un papel determinante en la evolución morfo-sedimentaria de este sistema durante el Plio-Cuaternario.

El análisis sísmico de perfiles de alta resolución del tipo ((uniboom)), realizados en la plataforma interna al N del Delta del Ebro, permite definir las unidades sísmicas y establecer la estructura sedimentaria del Ambos aspectos reflejan la influencia diferencial de los procesos recubrimiento cuaternario medio/superior. Ambos aspectos reflejan la influencia diferencial de los procesos dinámicos y de las oscilaciones eustáticas.

We used high-resolution swath-bathymetry data to characterise the morphology of the abandoned subaqueous Sol de Riu delta lobe in the Ebro Delta, Western Mediterranean Sea. This study aims to assess the influence of an abandoned delta lobe on present-day coastal dynamics in a micro-tidal environment. Detailed mapping of the relict Sol de Riu lobe also showed a set of bedforms interpreted as footprints of human activities: seasonal V-shaped depressions on the middle shoreface due to boat anchoring and old trawling marks between 16 and 18 m water depth. Estimations of the mobility of bottom sediment showed that the shallowest shoreface (i.e. less than 7 m depth) is the most dynamic part of the relict lobe, while the middle shoreface experienced significant morphological changes since the lobe was abandoned. The deepest shoreface (i.e. water depth in excess of 15 m), which corresponds to the front of the lobe, is defined by a very small potential for morphological change. Simulations showed that while the relict lobe does not significantly affect the typical short period waves (Tp ≈4 s) in the study area, it does interfere with the most energetic wave conditions (Tp ≥ 7 s) acting as a shoal leading to the concentration of wave energy along the shoreline northwest of the lobe. The consequence of such modification of the high-energy wave propagation pattern by the relict lobe is an alteration of the wave-induced littoral sediment dynamics with respect to a situation without the lobe.

Down-core samples of planktonic and benthic foraminifera were analyzed for oxygen and carbon isotopes in International Marine Past Global Changes Study (IMAGES) core MD99-2343 in order to study the interactions between climate change in the Northern Hemisphere and the western Mediterranean thermohaline circulation at times of Heinrich events (HE). Our results confirm the antiphase correlation between enhanced North Atlantic Deep Water formation and low ventilation in the Mediterranean. However, this study reveals that this antiphase relationship in deepwater formation between the North Atlantic and Mediterranean was interrupted during times of HE when the injection of large volumes of water from melting icebergs reached the entrance to the Mediterranean. These events, which lasted less than 1000 years, are represented by pronounced decreases in both planktonic delta(18)O and benthic delta(13)C signals. Lower salinities of Mediterranean surface water resulted in a slowdown of western Mediterranean deepwater overturn even though cold sea surface temperatures and drier climate should have resulted in enhanced deepwater formation.

Outcrops of old strata at the shelf edge resulting from erosive gravity-driven flows have been globally described on continental margins. The reexposure of old strata allows for the reintroduction of aged organic carbon (OC), sequestered in marine sediments for thousands of years, into the modern carbon cycle. This pool of reworked material represents an additional source of C-14-depleted organic carbon supplied to the ocean, in parallel with the weathering of fossil organic carbon delivered by rivers from land. To understand the dynamics and implications of this reexposure at the shelf edge, a biogeochemical study was carried out in the Gulf of Lions (Mediterranean Sea) where erosive processes, driven by shelf dense water cascading, are currently shaping the seafloor at the canyon heads. Mooring lines equipped with sediment traps and current meters were deployed during the cascading season in the southwestern canyon heads, whereas sediment cores were collected along the sediment dispersal system from the prodelta regions down to the canyon heads. Evidence from grain-size, X-radiographs and Pb-210 activity indicate the presence in the upper slope of a shelly-coarse surface stratum overlying a consolidated deposit. This erosive discontinuity was interpreted as being a result of dense water cascading that is able to generate sufficient shear stress at the canyon heads to mobilize the coarse surface layer, eroding the basal strata. As a result, a pool of aged organic carbon (Delta C-14 = -944.5 +/- 24.7%; mean age 23,650 +/- 3,321 ybp) outcrops at the modern seafloor and is reexposed to the contemporary carbon cycle. This basal deposit was found to have relatively high terrigenous organic carbon (lignin = 1.48 +/- 0.14 mg/100 mg OC), suggesting that this material was deposited during the last low sea-level stand. A few sediment trap samples showed anomalously depleted radiocarbon concentrations (Delta C-14 = -704.4 +/- 62.5%) relative to inner shelf (Delta C-14 = -293.4 +/- 134.0%), mid-shelf (Delta C-14 = -366.6 +/- 51.1%), and outer shelf (Delta C-14 = -384 +/- 47.8%) surface sediments. Therefore, although the major source of particulate material during the cascading season is resuspended shelf deposits, there is evidence that this aged pool of organic carbon can be eroded and laterally advected downslope.

Los Andes Patagónicos Septentrionales son una cordillera formada inicialmente por la subducción de las placas de Phoenix-Farallón y posteriormente por la de Nazca, que muestran rastros de deformación polifásica desde el Jurásico superior hasta el Neógeno, con posterioridad a la ruptura del Gondwana. El objetivo principal del trabajo es agrupar en dos ciclos esta secuencia compleja de eventos deformativos, los cuales sean dependientes de la distribución de edades en la trinchera oceánica durante la subducción. Al sur del paralelo 38° S, la génesis de los Andes Patagónicos Septentrionales está ligada a los efectos producidos por la colisión de dorsales oceánicas. La situación actual permite ilustrar cómo se produce la distribución de la deformación, durante una subducción oblicua, en un sistema con baja partición de la deformación. En los Andes Centrales Australes, al norte de los 38° S, la corteza se imbrica en el retroarco a partir de una distancia crítica de la dorsal oceánica de Chile. Cuando esta distancia es menor, el sistema de corrimientos en el retroarco se detiene, tal como ocurre en los Andes Patagónicos Septentrionales, donde subduce una corteza oceánica relativamente joven. Los cambios en el tiempo de la configuración oceánica a lo largo de la trinchera debido a la subducción, determinan que los modelos de deformación descritos varíen en el tiempo, pudiéndose definir dos modelos extremos: tipo Andes Patagónicos vs. Andes Centrales Australes. Durante los últimos 120 millones de años, en los Andes Patagónicos se han podido documentar, a partir de la interpretación del registro geológico, dos ciclos de apilamiento orogénico cortical con manifestación en sistemas de acortamiento en el retroarco y posterior fosilización del mismo, relacionados con el acercamiento, la colisión y la posterior subducción de una dorsal oceánica orientada oblicuamente con relación al margen occidental de la placa Sudamericana.