Crustal and upper mantle velocity structure of Southern Iberia, the sea of Alboran, and the Gibraltar arc determined by local earthquake tomography

Directory of Open Access Journals (Sweden)

M. J. Blanco

1997-06-01

Full Text Available A "local earthquake tomography" of a large area encompassing the South of Iberia, the sea of Alboran, the Gibraltar arc, and Northern Morrocco, has been performed using first arrival times recorded at various Spanish and Morroccan seismic networks. A total of 52 stations and 639 earthquakes provided over 6300 first P arrivals and 4400 S arrivals. Three features of interest appear in the results: i a continuous low velocity structure which correlates with the Betics, the Gibraltar arc and the Rif; ii a high velocity feature which persists to a depth of approximately 30 km, positioned near the coast of Malaga on the northern margin of the Alboran sea; iii a low velocity feature, extending to a minimum depth of approximately 40 km, which coincides with the Granada basin and a strong negative Bouguer gravity anomaly.

Le détroit de Gibraltar dans la mondialisation des transports maritimes

Directory of Open Access Journals (Sweden)

Nora Mareï

2012-02-01

Full Text Available Le détroit de Gibraltar est une voie de passage intercontinentale et interocéanique majeure. Tout autour du détroit trois Etats ont pris place : l’Espagne, le Maroc, le Royaume-Uni. Ils sont imbriquées les uns aux autres par un jeu d’enclaves territoriales et dépendent les uns des autres pour la circulation des biens et des personnes à travers le détroit. Cette circulation, intégrée dans les grands flux marchands et humains qui dominent la planète, fait toute l’attractivité des lieux et entraîne une organisation maritime et terrestre singulière autour de ce seuil océanique. En particulier, les terminaux portuaires se sont développés de manière spectaculaire et accueillent aujourd’hui les principaux transporteurs mondiaux. Cette faveur donnée au développement économique a de nombreux effets pervers, qui s’ils ne sont pas pris en compte rapidement, mèneront à une fragilisation des territoires frontaliers du détroit.The Strait of Gibraltar is a major intercontinental and interoceanic route for maritime traffic. Three states surrend the Strait: Spain, Morocco, and the United Kingdom. Being territorial enclaves, they overlap and depend of each others for regulating the circulation of goods and people through the strait. This intercirculation, integrated in major merchant and human flows which dominate the world, makes all the interest of the place and creates a singular maritime and spatial organization around this oceanic chokepoint. In particular, port terminals have grown rapidly and hosting major global carriers. But, the preminence given to the economic development has many perverse effects on the territories bordering the strait.

The Gibraltar Arc seismogenic zone and the great Lisbon earthquake of 1755

Science.gov (United States)

Gutscher, M.-A.; Malod, J. A.; Rehault, J.-P.; Thiebot, E.; Contrucci, I.; Baptista, M. A.; Miranda, J. M.

2003-04-01

New geophysical data provide compelling evidence for an active east dipping subduction zone beneath the Gibraltar Arc. SISMAR marine seismic data in the Gulf of Cadiz image an actively deforming accretionary wedge, with east dipping thrust faults disrupting the seafloor and soleing out to an east dipping decollement. Tomographic cross-sections as well as hypocenter distribution support a continuous east dipping slab of oceanic lithosphere from the Atlantic domain to beneath the Western Alboran Sea. The great Lisbon earthquake of 1755 (felt as far away as Hamburg, the Azores and Cape Verde Islands) has the largest documented felt area of any shallow earthquake and an estimated magnitude of 8.5 - 9.0. The associated tsunami ravaged the coast of SW Portugal and the Gulf of Cadiz, with run-up heights reported to have reached 5 - 15 m. While several source regions offshore SW Portugal have been proposed (e.g. - Gorringe Bank, Marques de Pombal fault), no single source appears to be able to account for the great seismic moment and the tsunami amplitude and travel-time observations. We propose the Gibraltar arc seismogenic zone to be the source of the 1755 earthquake. This hypothesis may be tested in several ways. We perform tsunami wave form modeling for a shallow east dipping fault plane with dimensions of 180 km (N-S) x 210 km (E-W) and a co-seismic slip of 20 m. For convergence rates of 1 - 2 cm/yr an event of this magnitude could recur every 1000 - 2000 years. Furthermore, the DELILA geophysical cruise is proposed for 2004 to conduct a bathymetric and seismic survey of the accretionary wedge and to sample the turbidites in the adjacent abyssal plains which record the history of great earthquakes.

Cultural contact over the Strait of Gibraltar during the Middle Palaeolithic? Evaluating the visibility of cultural exchange

Directory of Open Access Journals (Sweden)

Yvonne TAFELMAIER

2017-01-01

Full Text Available Possible contacts between hunter-gatherers of Northern Africa and Europe via the Strait of Gibraltar during the Pleistocene are still object to discussions. In the absence of significant fossil remains, debates are mainly based on similarities and differences of singular aspects of material culture. However, a theoretical framework for these discussions was lacking. The first aim of this study thus has been the development of a theoretical base. We therein included Maslow´s pyramid of basic needs. The idea of our approach is that the presence or absence of so-called cultural tracers identify either contact or disparity. A large database on archaeological sites of Morocco and Southern Iberia dating between 160 ka and 40 ka years ago has been compiled, containing information about lithic technology and typology, lithic raw material acquisition, subsistence patterns and symbolic behaviour. We formulated three potential contact scenarios between the two regions. The presence and/or absence of so-called cultural tracers within the data set, that covered all levels of Maslow´s pyramid, led us to conclude that – based on the present archaeological and anthropological data - no contact took place between Iberian and North African populations across the Strait of Gibraltar in the given time frame.

The antibacterial potential of the seaweeds (Rhodophyceae) of the Strait of Gibraltar and the Mediterranean Coast of Morocco

OpenAIRE

Rhimou, Bouhlal; Hassane, Riadi; Mart??nez L??pez, Jos??; Bourgougnon, Nathalie

2010-01-01

The antibacterial activity of extracts from 26 marine Rhodophyceae (8 Ceramiales, 7 Gelidiales, 9 Gigartinales, 1 Bonnemaisoniales and 1 Rhodymeniales) was studied to assess their potential in the pharmaceutical industry. Their bioactivity was analysed from crude methanolic extracts of dried samples against three gram-positive bacteria and two gram-negative bacteria using the disc diffusion technique. The samples were collected from Gibraltar and the Moroccan Mediterranean coast. Of the macro...

Remote environmental monitoring of the upper sea (REMUS) : Implementation in the strait of Gibraltar

International Nuclear Information System (INIS)

Mrabet, R.El.; Dehbi, N.; Khoukhi, T.El.; Laissaoui, A.; Delecaut, G.; Lacroix, J.P.; Abril, J.M.

2008-01-01

Full text: Interest in the need of environmental monitoring in the Gibraltar strait, in which a wide range of oceanic processes and interactions of global interest occur, has recently increased in order to ensure proper surveillance and control of marine pollution and consequently to complying with international recommendations and binding agreements pertaining to the protection of marine environment. The effects of the english submarine incident (end 2000) in the Gibraltar strait and the radiological incident of Algeciras, Spain (melting of a Cs- 137 source at a steel manufactory ACENIROX) suggest an adequate national and regional technical capabilities and expertise for long-term environmental monitoring as a key to control the area and to develop emergency model in the case of any future accident in the zone. REMUS involves new technologic developments that allow real-time and continuous remote monitoring of sea areas using autonomous probes in anchored buoys, powered with solar panels and equipped with low consumption sensors and one onboard PC that communicates via GSM with central laboratory in land. Sensors incorporate a very sensitive (few Bq m -3 ) NaI detector for gamma-emitting radionuclides, oceanographic instruments (current meters, CTDs), and chemical sensors (pH,chlorophyl1,..). This technology allows the remote environmental monitoring of the upper sea (although some additional sensors can be equally deployed in depth) combining the interest in the early detection of environmental risks (releases of many hazardous materials) and the fundmental research in marine systems, as chalenge in the preservation of natural resources and the human health through the knowledge. Thus, the development of predictive models is also one objective of this project. [fr

A rock engraving made by Neanderthals in Gibraltar.

Science.gov (United States)

Rodríguez-Vidal, Joaquín; d'Errico, Francesco; Giles Pacheco, Francisco; Blasco, Ruth; Rosell, Jordi; Jennings, Richard P; Queffelec, Alain; Finlayson, Geraldine; Fa, Darren A; Gutiérrez López, José María; Carrión, José S; Negro, Juan José; Finlayson, Stewart; Cáceres, Luís M; Bernal, Marco A; Fernández Jiménez, Santiago; Finlayson, Clive

2014-09-16

The production of purposely made painted or engraved designs on cave walls--a means of recording and transmitting symbolic codes in a durable manner--is recognized as a major cognitive step in human evolution. Considered exclusive to modern humans, this behavior has been used to argue in favor of significant cognitive differences between our direct ancestors and contemporary archaic hominins, including the Neanderthals. Here we present the first known example of an abstract pattern engraved by Neanderthals, from Gorham's Cave in Gibraltar. It consists of a deeply impressed cross-hatching carved into the bedrock of the cave that has remained covered by an undisturbed archaeological level containing Mousterian artifacts made by Neanderthals and is older than 39 cal kyr BP. Geochemical analysis of the epigenetic coating over the engravings and experimental replication show that the engraving was made before accumulation of the archaeological layers, and that most of the lines composing the design were made by repeatedly and carefully passing a pointed lithic tool into the grooves, excluding the possibility of an unintentional or utilitarian origin (e.g., food or fur processing). This discovery demonstrates the capacity of the Neanderthals for abstract thought and expression through the use of geometric forms.

La difícil aplicación de la estrategia marina europea y la protección del medio marino en la Bahía de Algeciras/Gibraltar

Directory of Open Access Journals (Sweden)

Inmaculada González García

2013-06-01

Full Text Available The transposal into national law of the European Marine Strategy represents the first step towards the establishment of the so-called European Maritime Policy. This new policy aims to provide a sustainable and coherent dimension to human interventions on the European coasts. In the Spanish case, the Law 41/2010 has transposed the EU Strategy in a much clearer manner than the wording of the EU lawmaker. One of the Spanish regions that necessitates demarcation lines is the area between the Strait of Gibraltar and Isla de Alborán, where maritime boundaries are yet to be defined. Indeed, the existence of a territorial dispute between Spain and the United Kingdom over the waters around Gibraltar and the recent conflict regarding the Sites of Community Importance (SCI have created serious difficulties in implementing the Marine Strategy.

Quantitative paleotopography and paleogeography around the Gibraltar Arc (South Spain) during the Messinian Salinity Crisis

Science.gov (United States)

Elez, Javier; Silva, Pablo G.; Huerta, Pedro; Perucha, M. Ángeles; Civis, Jorge; Roquero, Elvira; Rodríguez-Pascua, Miguel A.; Bardají, Teresa; Giner-Robles, Jorge L.; Martínez-Graña, Antonio

2016-12-01

The Malaga basin contains an important geological record documenting the complex paleogeographic evolution of the Gibraltar Arc before, during and after the closure and desiccation of the Mediterranean Sea triggered by the "Messinian Salinity crisis" (MSC). Proxy paleo-elevation data, estimated from the stratigraphic and geomorphological records, allow the building of quantitative paleogeoid, paleotopographic and paleogeographic models for the three main paleogeographic stages: pre-MSC (Tortonian-early Messinian), syn-MSC (late Messinian) and post-MSC (early Pliocene). The methodological workflow combines classical contouring procedures used in geology and isobase map models from geomorphometric analyses and proxy data overprinted on present Digital Terrain Models. The resulting terrain quantitative models have been arranged, managed and computed in a GIS environment. The computed terrain models enable the exploration of past landscapes usually beyond the reach of classical geomorphological analyses and strongly improve the paleogeographic and paleotopographic knowledge of the study area. The resulting models suggest the occurrence of a set of uplifted littoral erosive and paleokarstic landforms that evolved during pre-MSC times. These uplifted landform assemblages can explain the origin of key elements of the present landscape, such as the Torcal de Antequera and the large amount of mogote-like relict hills present in the zone, in terms of ancient uplifted tropical islands. The most prominent landform is the extensive erosional platform dominating the Betic frontal zone that represents the relic Atlantic wave cut platform elaborated during late-Tortonian to early Messinian times. The amount of uplift derived from paleogeoid models suggests that the area rose by about 340 m during the MSC. This points to isostatic uplift triggered by differential erosional unloading (towards the Mediterranean) as the main factor controlling landscape evolution in the area during

Estudio preliminar de los grabados rupestres de la Cueva del Moro (Tarifa, Cádiz y el arte paleolítico del Campo de Gibraltar

Directory of Open Access Journals (Sweden)

Mas Cornellà, Martí

1995-12-01

Full Text Available The spring of 1995 marked (he discovery of (he Cave of the Moro with a grout of horse engravings of undoubted Upper Palaeolithic date. The numerous other finds that have been made in recent years in the zone of the Campo de Gibraltar suggest that it is an area of great importance. Both the rock art and the material culture evidence, in the open air or in rock shelters, has continually increasing potential for study. Furthermore this group of sites represents the most southern Palaeolithic rock art in Europe.

En la primavera de 1995 se produjo el descubrimiento de la Cueva del Moro con un conjunto de figuraciones grabadas de équidos con. una filiación superopaleolítica indudable. Los numerosos hallazgos que se están produciendo desde hace unos años en la zona del Campo de Gibraltar nos indican que se trata de una área con una gran importancia y expectativas de estudio. Los hallazgos, tanto de arte rupestre como de cultura material, en estaciones al aire libre o en abrigos rocosos completan un panorama cada día más prometedor. Además este nuevo conjunto representa el arte rupestre paleolítico más meridional de Europa.

Modelo de predicción de la potencia de un parque eólico marino en el Estrecho de Gibraltar

OpenAIRE

Pino Domínguez, José Miguel del

2015-01-01

El objetivo último que motiva el desarrollo de este trabajo es construir un modelo de predicción de la potencia eléctrica que produciría un parque de aerogeneradores off-­‐shore en el Estrecho de Gibraltar, de unos 200 MW de potencia instalada, en periodos de un día, a partir de las predicciones de viento que proporciona ininterrumpidamente AEMET, la agencia estatal de meteorología española. Con este modelo predictivo se facilitaría la integración de la tan variable producción energética de l...

Large-scale block rotations from Late Tortonian to Present in the Gibraltar Arc System: input into the Messinian salinity crisis

Science.gov (United States)

Crespo-Blanc, Ana; Comas, Menchu; Balanyá, Juan Carlos

2016-04-01

We propose a reconstruction of one of the tightest orogenic arcs on Earth: the Gibraltar Arc System (GAS), which closes the Alpine-Mediterranean orogenic system to the west. This reconstruction, which includes onshore and offshore data, is completed for approximately 9 Ma, a few Ma before the Messinian Salinity Crisis (MSC). By that time a change in the direction of the Africa-Iberia convergence took place, the main shortening in the external wedge was accomplished, most of the low-angle normal fault systems that contribute to crustal-scale extension in the GAS ceased, and a significant emersion along the Africa and Iberia continental margins occurred, due to an overall contractive reorganization in the GAS. Our paleotectonic reconstruction is based on a review in terms of structures and age of the superposed deformational events that took place during the Miocene within the GAS, with special attention to the external zones of its northern branch. Our review and new structural data permit to constrain the timing of vertical axis-rotations evidenced by previously published paleomagnetic data, and to identify homogeneous domains in terms of relationships between timing of deformation events and block rotations. Block-rotations as high as 53° took place from 9 Ma to Present, which represents around 6°/Ma. The size of the rotated blocks reach 150 to 200 km long (measured along-strike). It implies that the rotations were accommodated by relatively rigid large-scale domains instead of smaller segments rotated progressively, which favors a model of vertical-axis block-rotations on top of crustal-scale decoupling levels. These rotations accommodated tightening and lengthening of the GAS and drastically altered its onshore and offshore geometry from 9 Ma onwards. In the back-arc Alboran Basin, this post-Miocene tightening produced inversion on Middle Miocene normal faults, wrench tectonics, the reactivation of shale diapirism and volcanism, and the uplift of the margins

Bringing back the bridge solution to establish a fixed link over the Strait of Gibraltar; Replanteamiento constructivo del Punte del Enlace Fijo a traves del Estrecho de Gibraltar

Energy Technology Data Exchange (ETDEWEB)

Diaz Simal, P.

2015-07-01

The aim of this essay is to address some of the aspects of the Bridge alternative and to examine the conclusions reached back in 1995 over the feasibility of such a solution. Although having been left aside for decades, the Bridge Solution of the Strait of Gibraltar Crossing Project has been brought back to life as an available alternative to close the gap between the two continents, being the reason to have recently detected some impediment down into the lower layers of the site laying grounds. All of which has revealed further geotechnical issues to tackle. Given the current level of development the Tunnel solution has reached, the 20-year-old Bridge solution needs to be fully updated in order to catch up with the former: As well as taking into consideration the new trends present in the state of the art on design of structures, the Bridge solution would also entail updating construction procedures if it is to incorporate all the potentialities offered by: (1) related tools (2) machinery, and (3), many new ideas which, coming from distinct industrial sectors others than the public works, have worked their way through the construction field. Furthermore, it would be necessary to bear in mind the ceaseless development materials science is going through, which involves constant increases in both levels of resilience and number of characteristics such materials present. (Author)

The North Atlantic Oscillation and sea surface temperature affect loggerhead abundance around the Strait of Gibraltar

Directory of Open Access Journals (Sweden)

José C. Báez

2011-04-01

Full Text Available The aim of this study was to explore the possible link between variations in the North Atlantic Oscillation (NAO and sea surface temperature (SST and the abundance of loggerhead turtles around the Strait of Gibraltar, using stranding data for the Andalusian coastal area as a proxy for abundance. The annual average SST (from November to October in the Gulf of Cadiz was negatively associated with the total number of loggerhead strandings each year from November 1997 to October 2006 in the Gulf of Cadiz and the Alboran Sea. The average NAO index was positively associated with the number of strandings in the Gulf of Cadiz in the following year. Prevailing westerly winds during positive NAO phases and the subsequent delayed decrease in SST may lead to turtles from the west Atlantic accumulating in the Gulf of Cadiz and unsuccessfully attempting to return. Secondary causes, such as buoyancy, cold stunning, longline fisheries, net fisheries, debilitated turtle syndrome, and trauma may also increase the number of turtle strandings.

Morpho-stratigraphic features of the northern shelf of the Strait of Gibraltar: Tectonic and sedimentary processes acting at different temporal scales

Science.gov (United States)

Luján, M.; Lobo, F. J.; Bruno, M.; de Castro, S.

2018-06-01

The northern shelf of the Strait of Gibraltar adjacent to Camarinal Sill, defined here as the Cape Paloma continental shelf, has been investigated by analyzing a set of geophysical data including multibeam bathymetric images, a side-scan sonar mosaic and high-resolution seismic profiles, and the simulation of water-mass circulation patterns along the northern coastal margin. The aim of the study was to establish the significance of factors determining the evolution of this shallow margin at different temporal scales and to assess the implications for bedform generation in strait settings, taking into account the complex tectonic evolution and the energetic hydrodynamic regime of the strait. Deformed basement rocks are part of the Betic-Rif thrust wedge, western Gibraltar Arc, mainly formed by the materials of the Flysch Complex units and covered by Pliocene to Quaternary post-orogenic deposits. A central high (Bajo de los Cabezos High) is delimited by lateral depressions, that nucleated two major depocentres with distinctive filling histories. The eastern depocentre is controlled by WNW-ESE faults cutting the Cretaceous-Miocene basement rocks; these faults generate horsts and grabens that could have contributed to the opening of the Strait of Gibraltar during the Pliocene. The largest and westernmost depocentre is related to the complete infilling of a shelf palaeovalley. The sediment cover is molded by different fields of submarine dunes and comet marks that indicate the influence of hydrodynamic processes on sediment transport at the coastal margin. The observations in the study area regarding bedform development must be placed into a wider context of strait sediment dynamics. The Cape Paloma continental shelf exhibits both erosional and depositional forms, due to its intermediate location between the strait, mostly dominated by erosional processes, and the Barbate Platform (northwest of the study area), mostly characterized by depositional forms. The long

Gibraltar, identidad de un colectivo de origen africano en el Zulia (1820-1840

Directory of Open Access Journals (Sweden)

Marisol Rodríguez Arrieta

2000-01-01

Full Text Available Gibraltar durante el siglo XIX fue el espacio atípico de la región zuliana. La forma de actuar y de resolver sus problemas al parecer responde al trato dado por las autoridades españolas y crio- llas durante dos siglos de historia esclavista; se constituyó en uno de los puertos más importantes y necesarios para pasar los productos que salían de Maracaibo y los que ésta recibía de Mérida y Tru- jillo. Su localización geográfica privilegiada fue el principal elemento que contribuyó a la creación de su identidad local, el apego a su espacio y las ventajas que este les ofreció permitió en el tiempo crear una micro-región con áreas productivas de gran provecho para los espacios ubicados en sus al - rededores. La defensa de su modo de vida, condujo al colectivo a enfrentarse con el centro de poder provincial; situación que hacía complejo el ejercicio del poder en la capital de la provincia ante la diversidad de demandas y formas de oposición. Las peculiaridades de su proceso histórico: pobla- ción no esclava logró en un período de larga duración definirse como un grupo social con sus pro- pios mecanismos y normativas de defensa y ataque.

Le domaine Tariquide (arc de Gibraltar, Espagne et Maroc) : succession sédimentaire et événements structuraux au Lias et au Dogger

Science.gov (United States)

Durand-Delga, Michel; Gardin, Silvia; Esteras, Manuel; Paquet, Hélène

2005-06-01

The Lias-Dogger successions of the Tariquide units in the Gibraltar Arc differ from the series of tectonically adjacent units, the Penibetic (Iberia margin) and the Limestone 'Dorsale' (Alboran Domain). Lower Lias limestones are eroded and covered by the Domerian, which starts by deposits of open sea, continuous up to the Dogger (J. Musa-type successions), and elsewhere (Los Pastores-type successions) by a thin series (Upper Lias to Upper Dogger), starting by a manganesiferous episode (Ras Leona) and including marls deposited into three episodes, dated by calcareous nannofossils. Faulting events occurred before the Domerian and during the Late Toarcian (Los Pastores). To cite this article: M. Durand-Delga et al., C. R. Geoscience 337 (2005).

Bringing back the bridge solution to establish a fixed link over the Strait of Gibraltar

International Nuclear Information System (INIS)

Diaz Simal, P.

2015-01-01

The aim of this essay is to address some of the aspects of the Bridge alternative and to examine the conclusions reached back in 1995 over the feasibility of such a solution. Although having been left aside for decades, the Bridge Solution of the Strait of Gibraltar Crossing Project has been brought back to life as an available alternative to close the gap between the two continents, being the reason to have recently detected some impediment down into the lower layers of the site laying grounds. All of which has revealed further geotechnical issues to tackle. Given the current level of development the Tunnel solution has reached, the 20-year-old Bridge solution needs to be fully updated in order to catch up with the former: As well as taking into consideration the new trends present in the state of the art on design of structures, the Bridge solution would also entail updating construction procedures if it is to incorporate all the potentialities offered by: (1) related tools (2) machinery, and (3), many new ideas which, coming from distinct industrial sectors others than the public works, have worked their way through the construction field. Furthermore, it would be necessary to bear in mind the ceaseless development materials science is going through, which involves constant increases in both levels of resilience and number of characteristics such materials present. (Author)

Prehistoric contacts over the Straits of Gibraltar indicated by genetic analysis of Iberian Bronze Age cattle.

Science.gov (United States)

Anderung, Cecilia; Bouwman, Abigail; Persson, Per; Carretero, José Miguel; Ortega, Ana Isabel; Elburg, Rengert; Smith, Colin; Arsuaga, Juan Luis; Ellegren, Hans; Götherström, Anders

2005-06-14

The geographic situation of the Iberian Peninsula makes it a natural link between Europe and North Africa. However, it is a matter of debate to what extent African influences via the Straits Gibraltar have affected Iberia's prehistoric development. Because early African pastoralist communities were dedicated to cattle breeding, a possible means to detect prehistoric African-Iberian contacts might be to analyze the origin of cattle breeds on the Iberian Peninsula. Some contemporary Iberian cattle breeds show a mtDNA haplotype, T1, that is characteristic to African breeds, generally explained as being the result of the Muslim expansion of the 8th century A.D., and of modern imports. To test a possible earlier African influence, we analyzed mtDNA of Bronze Age cattle from the Portalón cave at the Atapuerca site in northern Spain. Although the majority of samples showed the haplotype T3 that dominates among European breeds of today, the T1 haplotype was found in one specimen radiocarbon dated 1800 calibrated years B.C. Accepting T1 as being of African origin, this result indicates prehistoric African-Iberian contacts and lends support to archaeological finds linking early African and Iberian cultures. We also found a wild ox haplotype in the Iberian Bronze Age sample, reflecting local hybridization or backcrossing or that aurochs were hunted by these farming cultures.

Más allá de Paco de Lucía. Una aproximación a la tradición del flamenco en el Campo de Gibraltar, Cádiz

Directory of Open Access Journals (Sweden)

Juan José Téllez

2009-01-01

Full Text Available La importancia, mediática, histórica y artística generada por Paco de Lucía, tanto por el mismo como en su acompañamiento a ya mítico Camarón de la Isla ha generado un velo que enturbia al arte flamenco de todo el Campo de Gibraltar. Sin minusvalorar el aporte de la familia algecireña Sánchez la tradición jonda se puede rastrear hasta el siglo XVII y pervive en jóvenes valores del cante, el toque y el baile hasta el día de hoy. Como ejemplo basta mencionar dos nombres que son ejemplo de la pervivencia flamenca Corruco y la zaga de Los Chaqueta.

Propagation of uncertainties for an evaluation of the Azores-Gibraltar Fracture Zone tsunamigenic potential

Science.gov (United States)

Antoshchenkova, Ekaterina; Imbert, David; Richet, Yann; Bardet, Lise; Duluc, Claire-Marie; Rebour, Vincent; Gailler, Audrey; Hébert, Hélène

2016-04-01

The aim of this study is to assess evaluation the tsunamigenic potential of the Azores-Gibraltar Fracture Zone (AGFZ). This work is part of the French project TANDEM (Tsunamis in the Atlantic and English ChaNnel: Definition of the Effects through numerical Modeling; www-tandem.cea.fr), special attention is paid to French Atlantic coasts. Structurally, the AGFZ region is complex and not well understood. However, a lot of its faults produce earthquakes with significant vertical slip, of a type that can result in tsunami. We use the major tsunami event of the AGFZ on purpose to have a regional estimation of the tsunamigenic potential of this zone. The major reported event for this zone is the 1755 Lisbon event. There are large uncertainties concerning source location and focal mechanism of this earthquake. Hence, simple deterministic approach is not sufficient to cover on the one side the whole AGFZ with its geological complexity and on the other side the lack of information concerning the 1755 Lisbon tsunami. A parametric modeling environment Promethée (promethee.irsn.org/doku.php) was coupled to tsunami simulation software based on shallow water equations with the aim of propagation of uncertainties. Such a statistic point of view allows us to work with multiple hypotheses simultaneously. In our work we introduce the seismic source parameters in a form of distributions, thus giving a data base of thousands of tsunami scenarios and tsunami wave height distributions. Exploring our tsunami scenarios data base we present preliminary results for France. Tsunami wave heights (within one standard deviation of the mean) can be about 0.5 m - 1 m for the Atlantic coast and approaching 0.3 m for the English Channel.

FCJ-140 Radio Feeds, Satellite Feeds, Network Feeds: Subjectivity Across the Straits of Gibraltar.

Directory of Open Access Journals (Sweden)

Nicholas Knouf

2012-07-01

Full Text Available This paper engages with the practices surrounding the two fadaiat encounters that took place simultaneously in Spain and Morocco in the summers of 2004 and 2005 (see http://fadaiat.net/ .  The fadaiat project focused on the question of immigration to Europe, specifically from northern Africa, and the ‘Fortress Europe’ responses by European Union governments.  Participants in fadaiat included academic scholars, free software developers, artists, and activists, forming a meta-network that created bridges across disparate communities and practices.  In particular, the participation of the Spanish collective hackitectura was key; they describe themselves as a ‘posse of architects, hackers and social activists experimenting in the merging territories of recombining spatial cyborgs composed by physical spaces, ICT networks and bodies’.  hackitectura led the development of both a temporary civil, non-commercial wireless link across the straits of Gibraltar between Tarifa, Spain and Tangier, Morocco, as well as an entirely free software audio/video streaming system, that enabled participants on both sides to come together independently of the restrictions normally placed on such movement by immigration laws.The importance of free software for fadaiat extends beyond its purely instrumental use as an agent for disrupting state control.  Indeed, the imagery of computation and free software – networks, links, patches, nodes, penguins – pervades the documentation of the project.  Rave parties simulcast across the straits are as important as the discussions and software produced.  I suggest that this can be understood as developing new forms of subjectivity, in the sense given by Felix Guattari, and therefore link the fadaiat project to earlier pirate radio practices, especially Radio Alice in Bologna, Italy, in which Guattari was involved.

Improving the analysis of biogeochemical patterns associated with internal waves in the strait of Gibraltar using remote sensing images

Science.gov (United States)

Navarro, Gabriel; Vicent, Jorge; Caballero, Isabel; Gómez-Enri, Jesús; Morris, Edward P.; Sabater, Neus; Macías, Diego; Bolado-Penagos, Marina; Gomiz, Juan Jesús; Bruno, Miguel; Caldeira, Rui; Vázquez, Águeda

2018-05-01

High Amplitude Internal Waves (HAIWs) are physical processes observed in the Strait of Gibraltar (the narrow channel between the Atlantic Ocean and the Mediterranean Sea). These internal waves are generated over the Camarinal Sill (western side of the strait) during the tidal outflow (toward the Atlantic Ocean) when critical hydraulic conditions are established. HAIWs remain over the sill for up to 4 h until the outflow slackens, being then released (mostly) towards the Mediterranean Sea. These have been previously observed using Synthetic Aperture Radar (SAR), which captures variations in surface water roughness. However, in this work we use high resolution optical remote sensing, with the aim of examining the influence of HAIWs on biogeochemical processes. We used hyperspectral images from the Hyperspectral Imager for the Coastal Ocean (HICO) and high spatial resolution (10 m) images from the MultiSpectral Instrument (MSI) onboard the Sentinel-2A satellite. This work represents the first attempt to examine the relation between internal wave generation and the water constituents of the Camarinal Sill using hyperspectral and high spatial resolution remote sensing images. This enhanced spatial and spectral resolution revealed the detailed biogeochemical patterns associated with the internal waves and suggests local enhancements of productivity associated with internal waves trains.

“Hace dos años para atrás que fui a Egipto...”: sobre algunas semejanzas entre el español de Gibraltar o yanito y el español de Estados Unidos”

Directory of Open Access Journals (Sweden)

Elena Errico

2015-12-01

Full Text Available The situation of contact between English and Spanish in the United States bears some resemblance with that of Gibraltar. Significant similarities can be identified both at a sociolinguistic and linguistic as well as discursive level, despite the apparent profound demographic, political, social and cultural differences between the two Spanish-speaking communities. Based on a corpus of compositions written by Gibraltarian adolescents, I analyze a number of structural and discursive features that differentiate Gibraltarian Spanish or Yanito from Andalusian Spanish and that, conversely, are well-documented in the speech of US Spanish transitional bilinguals.

Vertical structure of currents in Algeciras Bay (Strait of Gibraltar): implications on oil spill modeling under different typical scenarios

Science.gov (United States)

Megías Trujillo, Bárbara; Caballero de Frutos, Isabel; López Comi, Laura; Tejedor Alvarez, Begoña.; Izquierdo González, Alfredo; Gonzales Mejías, Carlos Jose; Alvarez Esteban, Óscar; Mañanes Salinas, Rafael; Comerma, Eric

2010-05-01

Algeciras Bay constitutes a physical environment of special characteristics, due to its bathymetric configuration and geographical location, at the eastern boundary of the Strait of Gibraltar. Hence, the Bay is subject to the complex hydrodynamics of the Strait of Gibraltar, characterized by a mesotidal, semidiurnal regime and the high density-stratification of the water column due to the presence of the upper Atlantic and the lower Mediterranean (more salty and cold) water layers. In addition, this environment is affected by powerful Easterly and Westerly winds episodes. The intense maritime traffic of oil tankers sailing across the Strait and inside the Bay, together with the presence of an oil refinery at its northern coast, imply high risks of oil spilling inside these waters, and unfortunately it has constituted a matter of usual occurrence through the last decades. The above paragraph clearly manifests the necessity of a detailed knowledge on the Bay's hydrodynamics, and the related system of currents, for a correct management and contingency planning in case of oil spilling in this environment. In order to evaluate the range of affectation of oil spills in the Bay's waters and coasts, the OILMAP oil spill model was used, the currents fields being provided by the three-dimensional, nonlinear, finite-differences, sigma-coordinates, UCA 3D hydrodynamic model. Numerical simulations were carried out for a grid domain extended from the western Strait boundary to the Alboran Sea, having a horizontal spatial resolution of 500 m and 50 sigma-levels in the vertical dimension. The system was forced by the tidal constituents M2 (main semidiurnal) and Z0 (constant or zero-frequency), considering three different typical wind conditions: Easterlies, Westerlies and calm (no wind). The most remarkable results from the numerical 3D simulations of Algeciras Bay's hydrodynamics were: a) the occurrence of opposite tidal currents between the upper Atlantic and lower Mediterranean

Le domaine Tariquide (arc de Gibraltar, Espagne et Maroc) : succession et hiatus de la sédimentation du Jurassique supérieur au Paléocène

Science.gov (United States)

Durand-Delga, Michel; Esteras, Manuel; Gardin, Silvia; Paquet, Hélène

2005-07-01

The originality of the Malm-Cretaceous series of the Tariquides (Gibraltar arc), as compared to those of the Rifian-Betic 'Dorsale' (Alboran domain), and especially with the Penibetic (Iberia) domain, is emphasized. In the Los Pastores Group, near Algeciras, Upper Tithonian nodular limestones directly lie on the Dogger and are followed by Aptychus-bearing limestones (Late Berriasian to Barremian). In the Musa Group, Rif, radiolarites are followed by siliceous limestones (Kimmeridgian-Tithonian), then by karst and massflow breccias connected to a Berriasian tectonics, by Aptychus-bearing marly limestones, then by karst filled by Turonian limestones, and finally by Maastrichtian-Palaeocene polychrome pelites, whose micropalaeontological and mineral compositions (clay minerals, Fe sbnd Mn nodules) refer to a deep-sea, probably infra-CCD, sedimentation. To cite this article: M. Durand-Delga et al., C. R. Geoscience 337 (2005).

Sedimentary infilling of bedrock-controlled palaeo-embayments off Cape Trafalgar, Strait of Gibraltar (Gulf of Cadiz)

Science.gov (United States)

de Castro, Sandra; Lobo, Francisco J.

2018-02-01

This study investigates two bedrock-controlled palaeo-coastal embayments on the Barbate Platform off Cape Trafalgar near the Strait of Gibraltar (Gulf of Cadiz shelf, SW Iberian Peninsula), aiming to reveal their infilling dynamics and the influence of rocky outcrops on shallow-water hydrodynamics and sediment transport. The approach relies on detailed multibeam bathymetric data, high-resolution seismic profiles and tidal current simulations. Elongated rocky outcrops formed a palaeo-coast when sea level was approximately 35 to 20 m below that of the present day, and bound a relatively flat area. However, the seismic profiles enabled to distinguish two main troughs (A and B) that were infilled following a distinctive evolution during the last transgression. Five seismic units were identified (I to V, from base to top). Deposit A is composed of seismic units II to V and is interpreted as a marine embayment infill, here termed the Barbate palaeo-embayment (BPE). Deposit B is composed of seismic units I to IV and is interpreted as a palaeo-valley infill, here termed the Barbate palaeo-valley (BPV). The complex internal stratigraphic architecture depicts an overall evolution from tidal/fluvial deposits to shallow-water marine deposits. Most significant is the occurrence of coupled tidal flats/estuarine sand bars constituting the infilling of the BPE; this suggests the persistence of a high-energy current in a shallow, confined embayment, which was amplified by the rocky outcrop constrictions and possibly facilitated by the episodic movement of a normal fault. In contrast to this active setting, the nearby straight and narrow BPV was subjected to lower-energy infilling dynamics during its initial flooding phases. There, tidal activity was possibly reduced by the straight morphology of the valley and the occurrence of a topographic constriction (i.e. the Barbate Passage) at the mouth of the valley.

BROTE DE SARAMPIÓN EN CAMPO DE GIBRALTAR, CÁDIZ, DURANTE EL PERÍODO FEBRERO-JULIO 2008

Directory of Open Access Journals (Sweden)

Juan Nieto Vera

2010-01-01

Full Text Available Fundamento: El 4 de febrero de 2008 se notificó a la Red de Vigilancia Epidemiológica de Andalucía (SVEA, 2 casos de sarampión vinculados epidemiológicamente, 2 tripulantes del Fast-Ferry Jaime I de la Compañía Balearia, que realiza la línea de Algeciras - Tánger. El objetivo de este trabajo es caracterizar epidemiológicamente el brote de ámbito poblacional detectado en la Comarca Campo de Gibraltar, las medidas de control implementadas y la efectividad vacunal. Método: Estudio observacional descriptivo de casos notificados. Se analizan las variables edad, sexo, municipio de residencia, sintomatología, fecha de inicio, colectivos implicados, estado vacunal previo, intervenciones realizadas, genotipo del virus, y efectividad vacunal. Fuentes de información los registros del SVEA, programa de vacunas e historia digital individual (Diraya. Se calcularon tasas x 105 por grupo de edad y medidas de frecuencia. Para comparación de efectividad vacunal se utilizó test Chi2. Resultados: Se confirmaron 155 casos de sarampión, 88.4% por laboratorio. Grupos de edad mas afectados menores de 2 años (19% y de 21 a 40 (51%. El 54.2% varones. El 72,14% no estaban vacunados. Se aisló virus sarampión Genotipo D4 importado. La efectividad vacunal era superior al 99%. Conclusiones: Se confirma un brote por virus del sarampión importado. Mas de la mitad de los casos no estaban vacunados. La disminución de la incidencia en vacunados hace necesario recomendar campañas de Cacht - Up que aumenten las coberturas para evitar la aparición de estos brotes vacunales.

Development of a Cold Sterilant for Field Medical Use.

Science.gov (United States)

1996-11-01

ppendices ............................................... 62 A ppendices ....................................................... 67 * ALL INFORMATION...Values At 20’C ............ 509 Gibraltar Report G-76647 - Acute Dermal on STERIS 20C .......................... 533 Gibraltar Report G-76364 - Primary...Report G-76487 - Acute Oral Toxicity Test on STERIS 20C ................. 566 Gibraltar Report G-77120 - Beuhler Guinea Pig Hypersensitivity Test on

Seafloor morphology of the Eurasia-Nubia (Africa) plate boundary between the Tore-Madeira Rise and the Straits of Gibraltar: a case of coexistent Mesozoic through Present day features of tectonic, oceanographic and sedimentary origin

Science.gov (United States)

Terrinha, Pedro; Duarte, João.; Valadares, Vasco; Batista, Luis; Zitellini, Nevio; Grácia, Eulalia; Lourenço, Nuno; Rosas, Filipe; Roque, Cristina

2010-05-01

The joint use of more than 10.000 km multichannel seismic reflection profiles and 180.000km2 of multibeam swath bathymetry and backscatter allowed for a new vision of the seafloor tectonic and geomorphic processes of the area that encompasses the present day plate boundary between Africa and Eurasia, between the Gibraltar Straits and the Tore-Madeira Rise, in the southern sector of the North Atlantic Ocean. The interpretation of this data allowed for the detailed description of the seafloor morphology (i.e. a morphologic map) and the classification of the morphologic features in what respects the genetic process and age. It can be seen that in the same region coexist morphologic features that result from tectonic processes associated with the Triassic-Cretaceous break-up of Pangea, the Paleogene-Miocene compressive phase, the Miocene through Present subduction under the Gibraltar Arc (Gutscher et al., 2002), the Pliocene-Quaternary wrench tectonics and possible coeval plate boundary (Zitellini et al., 2009), the Present day mud volcanism and propagation of the compressive deformation along the West Continental Margin of Portugal (Terrinha et al., 2009). Interpretation of the seismic profiles together with the bathymetry allows the understanding of endogenous and exogenous processes that creates reliefs associated with active structures (related to the Miocene through Present compressive stress field). Other reliefs generated in Mesozoic times by analogous processes can be as well preserved as these active ones. In what concerns exogenous processes, the analysis of the two datasets (reflection seismics and bathymetry) allowed for the description of morphologic features associated with oceanic currents that interact with the seafloor forming these important features. As is the case of the well known active contourites but also less known features, like giant scours at 4 km water depth that have recently been described, suggesting the interaction of deep currents and

Mineralogía y génesis de las arcillas de la Unidad de Almarchal (series flysch del Campo de Gibraltar. S de España

Directory of Open Access Journals (Sweden)

Carrasco, F.

1990-08-01

Full Text Available A study of the fine fraction of the Almarchal unit (Campo de Gibraltar flysch series revealed several very characteristic mineralogical associations, closely associated with the types of the rocks in this area. 1. Kaolinite-(illite-swelling minerals, characteristically associated with the lutitic leves, clearly preponderate in this unit.2. Illite-chlorite, a well-developed association found only in calcareous rocks. 3. Chlorite and/or berthierine, a characteristic association of silicified levels. Thus, it is possible to determine a group of levels, typically turbiditic and another group of lutitic levels, probably hemipelagic deposits, in which the content of organic material is noteworthy. The control of the mineralogic evolution by lithology is a result of different permeabilities in alternating levels. In calcareous beds the mineralogy of the fine fraction could result from the diagenetic degradation of aluminosilicates. Diagenetic Fe-rich chlorites, preferably developed in siliceous rocks resulting from the evolution of detrital kaolinites. In lutitic beds, two types of mineral constituents are mixed: Typically detrital mineral species (like kaolinite and diagenetic materials (swelling minerals. The abundance of organic matter in these levels can be related with oceanic anoxic events in Cretaceous time in North Atlantic basins.El estudio de la fracción fina de la Unidad de Almarchal (series flysch del Campo de Gibraltar ha permitido poner de manifiesto varias asociaciones mineralógicas relacionadas estrechamente con los tipos litológicos presentes: 1. Caolinita-(ilita-minerales hinchables, asociación propia de los niveles lutíticos, claramente dominantes en esta Unidad.2. Bita-clorita, asociación bien desarrollada en las rocas calcáreas.3. Clorita y/o bertierina, minerales que caracterizan a los niveles silicificados.En la mayor parte de las secuencias es posible, por lo tanto, determinar una serie de niveles típicamente turbid

Which fault destroyed Fes city (Morocco) in 1755? A new insight from the Holocene deformations observed along the southern border of Gibraltar arc

Science.gov (United States)

Poujol, Antoine; Ritz, Jean-François; Vernant, Philippe; Huot, Sebastien; Maate, Soufian; Tahayt, Abdelilah

2017-08-01

In this paper, we present the first estimate of the Holocene deformation along the southern front of Gibraltar arc (Morocco) and the first field constraints on the local 1755 CE Fes-Meknes surface rupturing earthquake which could be associated to the "Great Lisbon Earthquake" (M > 8.5) in November 1st, 1755. Using satellite imagery, aerial photographs and field investigations, we carried out a morphotectonic study along the 150 km-long Southern Rif Front (SRF) to identify the most recent evidences of tectonic activity. Analyzed offset alluvial deposits confirm that (i) the last 5 ka cumulative deformation leading to a slip rate of 3.5 ± 1 mm/yr for this segment of the SRF is consistent with the GPS derived horizontal shortening rate of 2-4 mm/yr and (ii) a recent major earthquake ruptured a 30 km-long segment along the SRF. Based on deposits dating and historical seismicity we propose that this seismic event occurred in 1755 as a local earthquake. Even though this 1755 local event cannot be considered as a strong aftershock of the main Lisbon seismic event (M > 8.5), their temporal closeness, their occurrence under the same convergent stress regime ( NNW-SSE-oriented compression) and the fact that Fes-Meknes area was strongly shaken during the Lisbon earthquake, raises the question of the possible triggering of the Fes earthquake. Anyway, our new results suggest that most of the Nubia-Rif belt convergence is accommodated by the SRF, making it potentially the most destructive structure of the Rif.

Biometry and phenology of two sibling Phylloscopus warblers on their circum-Mediterranean migrations.

Science.gov (United States)

Zduniak, Piotr; Yosef, Reuven; Bensusan, Keith J; Perez, Charles E; Tryjanowski, Piotr

2015-01-01

The Mediterranean Sea is known as an ecological barrier for numerous migratory birds flying from European breeding grounds to African wintering sites. Birds generally avoid migration over open sea and fly over land. In the Mediterranean Basin, few land bridges or bottlenecks for migratory birds exist. The narrowest are at the western and eastern extremes: the Strait of Gibraltar and Israel. Comparative studies between these locations are extremely rare to date. Therefore, in order to elucidate the differences between the two flyways, we compared data collected simultaneously for two sister leaf warbler species, the Bonelli's Warbler complex, Phylloscopus bonelli and Phylloscopus orientalis, at ringing stations in the western Mediterranean Basin Gibraltar, and the eastern Eilat, Israel. Data on biometrics and passage dates of individuals trapped at Gibraltar and Eilat were used, and it was found that mean arrival date of Western Bonelli's Warblers at Gibraltar was 15 days later than Eastern Bonelli's Warblers at Eilat. Furthermore, Western Bonelli's Warblers had shorter wings than Eastern Bonelli's Warblers. On the other hand, birds in Eilat were in poorer body condition than individuals in Gibraltar. The comparison between geographically distant stop-over sites contributes to furthering our understanding of the development of migration strategies across ecological barriers in sibling species. Our study showed that populations that breed in southwestern Europe migrate through Gibraltar and winter in West Africa are able to accomplish migration in comparatively good body condition. This is in contrast to those that winter in East Africa, migrate through Israel and have to endure the combined challenge of crossing the Sahel, Sahara and Sinai deserts before reaching their breeding grounds across southeast Europe and southwest Asia. Hence, the discrepancies described between the western and the eastern flyway suggest that individuals in the west, in general, migrate

The role of the Strait of Gibraltar in shaping the genetic structure of the Mediterranean Grenadier, Coryphaenoides mediterraneus, between the Atlantic and Mediterranean Sea.

Directory of Open Access Journals (Sweden)

Diana Catarino

Full Text Available Population genetic studies of species inhabiting the deepest parts of the oceans are still scarce and only until recently we started to understand how oceanographic processes and topography affect dispersal and gene flow patterns. The aim of this study was to investigate the spatial population genetic structure of the bathyal bony fish Coryphaenoides mediterraneus, with a focus on the Atlantic-Mediterranean transition. We used nine nuclear microsatellites and the mitochondrial cytochrome c oxidase I gene from 6 different sampling areas. No population genetic structure was found within Mediterranean with both marker types (mean ΦST = 0.0960, FST = -0.0003, for both P > 0.05. However, within the Atlantic a contrasting pattern of genetic structure was found for the mtDNA and nuclear markers (mean ΦST = 0.2479, P 0.05. When comparing samples from Atlantic and Mediterranean they exhibited high and significant levels of genetic divergence (mean ΦST = 0.7171, FST = 0.0245, for both P < 0.001 regardless the genetic marker used. Furthermore, no shared haplotypes were found between Atlantic and Mediterranean populations. These results suggest very limited genetic exchange between Atlantic and Mediterranean populations of C. mediterraneus, likely due to the shallow bathymetry of the Strait of Gibraltar acting as a barrier to gene flow. This physical barrier not only prevents the direct interactions between the deep-living adults, but also must prevent interchange of pelagic early life stages between the two basins. According to Bayesian simulations it is likely that Atlantic and Mediterranean populations of C. mediterraneus were separated during the late Pleistocene, which is congruent with results for other deep-sea fish from the same region.

Vender cara la victoria al enemigo : España, el escenario europeo y la independencia de los Estados Unidos.

Directory of Open Access Journals (Sweden)

Thomas E. Chavez

2001-01-01

Full Text Available El sitio de Gibraltar mantuvo ocupada a la flota inglesa, evitando así el desplazamiento de barcos y de tropas a América. Inglaterra pudo retener la plaza en su poder, pero a cambio perdió Menorca y, sobre todo, hubo de firmar la paz con los rebeldes americanos, renunciando a su dominio sobre las Trece Colonias.The siege of Gibraltar kept the English Navy frozen and prevented England from sending ships and troops to America. Thus, England could keep Gibraltar in its hands, but, in turn, lost Mlnorca and, above all, had to sign the peace with American rebels and to give up its hold on American Thirteen Colonies.

A rapid method to map the crustal and lithospheric thickness using elevation, geoid anomaly and thermal analysis. Application to the Gibraltar Arc System, Atlas Mountains and adjacent zones

Science.gov (United States)

Fullea, J.; Fernàndez, M.; Zeyen, H.; Vergés, J.

2007-02-01

We present a method based on the combination of elevation and geoid anomaly data together with thermal field to map crustal and lithospheric thickness. The main assumptions are local isostasy and a four-layered model composed of crust, lithospheric mantle, sea water and the asthenosphere. We consider a linear density gradient for the crust and a temperature dependent density for the lithospheric mantle. We perform sensitivity tests to evaluate the effect of the variation of the model parameters and the influence of RMS error of elevation and geoid anomaly databases. The application of this method to the Gibraltar Arc System, Atlas Mountains and adjacent zones reveals the presence of a lithospheric thinning zone, SW-NE oriented. This zone affects the High and Middle Atlas and extends from the Canary Islands to the eastern Alboran Basin and is probably linked with a similarly trending zone of thick lithosphere constituting the western Betics, eastern Rif, Rharb Basin, and Gulf of Cadiz. A number of different, even mutually opposite, geodynamic models have been proposed to explain the origin and evolution of the study area. Our results suggest that a plausible slab-retreating model should incorporate tear and asymmetric roll-back of the subducting slab to fit the present-day observed lithosphere geometry. In this context, the lithospheric thinning would be caused by lateral asthenospheric flow. An alternative mechanism responsible for lithospheric thinning is the presence of a hot magmatic reservoir derived from a deep ancient plume centred in the Canary Island, and extending as far as Central Europe.

Las relaciones hispano- británicas bajo el franquismo, 1950- 1973

Directory of Open Access Journals (Sweden)

Carolina LABARTA RODRÍGUEZ-MARIBONA

2010-02-01

Full Text Available RESUMEN: El artículo describe cómo Gran Bretaña abordó las relaciones con España desde el período en que ésta inició el regreso a la comunidad internacional, hasta 1973, cuándo el fracaso de las conversaciones sobre Gibraltar terminó un breve período de acercamiento entre los dos países. Durante todo el período dos son los temas dominantes en las relaciones hispano-británicas: por un lado, la cuestión de Gibraltar; por otro, especialmente a partir de 1957, los intentos españoles de conseguir una integración más estrecha con Europa Occidental que suavice su excesiva dependencia de los Estados Unidos. El crecimiento económico experimentado a partir del Plan de Estabilización de 1959 abrirá nuevas posibilidades a la política exterior española al hacer su asociación más atractiva para una Gran Bretaña enfrascada en una ardua lucha por mantener sus mercados frente a la competencia de la Europa del Mercado Común. Palabras clave: Gran Bretaña, España, política exterior, Franquismo, Gibraltar.ABSTRACT: This article deals with Anglo-Spanish relations from the moment in which Spain returns to the international community to the failure of the Anglo- Spanish Conversations over Gibraltar in 1973, which ended a brief period of rapprochement between the two countries. During the whole period, two issues will dominate Anglo-Spanish relations: on the one hand, the Gibraltar question; on the other, and especially from 1957 on, Spanish attempts to achieve a closer integration with Western Europe in order to diminish its excessive dependency on the United States. New possibilities will be opened to Spanish foreign policy when the economic growth experienced after the 1959 Stabilization Plan makes Spain a much more attractive partner for a Britain struggling to keep her markets against the growing Common Market competition. Keywords: Great Britain, Spain, foreign policy, the Franco Regime, Gibraltar.

Closure of the Africa-Eurasia-North America plate motion circuit and tectonics of the Gloria fault

Science.gov (United States)

Argus, Donald F.; Gordon, Richard G.; Demets, Charles; Stein, Seth

1989-01-01

The current motions of the African, Eurasian, and North American plates are examined. The problems addressed include whether there is resolvable motion of a Spitsbergen microplate, the direction of motion between the African and North American plates, whether the Gloria fault is an active transform fault, and the implications of plate circuit closures for rates of intraplate deformation. Marine geophysical data and magnetic profiles are used to construct a model which predicts about 4 mm/yr slip across the Azores-Gibraltar Ridge, and west-northwest convergence near Gibraltar. The analyzed data are consistent with a rigid plate model with the Gloria fault being a transform fault.

Formación de corrensita en turbiditas calcáreas con silex del Campo de Gibraltar (SW de España

Directory of Open Access Journals (Sweden)

Carrasco, F.

1988-04-01

Full Text Available In this paper is considered the relationship between the process of silicification in turbiditic limeslones and tbe growth of corrensite. This mineralogy is thought to be a result of two fundamental faetors: a Type of detrital material, and b Diagenetic conditions of the environment. Type of detrital material (in general similar to that found in otber calcareous rocks of the Campo de Gibraltar Units determine tbe presence of illite and mixed-layers illite smectite, limited smectite and scarce kaolinite. Diagenetic environment is responsible for the corrensite and possible zeolite growth, and the carbonate silicification. The paragenesis and cbemical characteristics studied showed that the environment for the formation of these minerals needs a high activity of silica in solutions, a high content of iron (divalent and magnesium, but is not necesarily be in relation with evaporitic deposits and thus alkaline conditions of formations. In this examples, the silicification process of limestone (which shows in the chemical analysis a certain proportion of iron and magnesium is accompanied by iron oxides growth. The release of magnesium did not, as it frequently does, cause dolomite growth but, instead, led lo the corrensite formation. Because of the absence of siliceous organisms (radiolarian, sponge-spicules... in this racles, the silicification process which has conduced lo development of chert nadules probably took place in an early stage of diagenesis, using silica precipitation from the solution. In this case, the volcanic activity cannot be considered as a last source of silica, as there is no evidence for contemporary volcanism with the sedimentation of these materials.Este trabajo tiene como objetivo fundamental el poner de manifiesto las relaciones que existen entre el proceso de silicificación de las calizas turbidíticas y el desarrollo de corrensita. La mineralogía determinada viene condicionada por dos factores: tipo de aportes y

¿Brexit? Escenarios internacionales y Gibraltar

OpenAIRE

Mangas, Araceli

2016-01-01

La hipótesis de este trabajo es analizar los escenarios internacionales post-Brexit. La retirada del Reino Unido de la Unión Europea tendrá efectos diversos en las relaciones exteriores de la Unión; el Reino Unido no recuperará su pasado, no volverá a 1972, no hay restitutio in integrum. Tendrá que reconstruir su propia red de acuerdos con terceros. Habrá un impacto relativo sobre la Política Exterior y de Seguridad Común (PESC) y en seguridad y defensa, mayor en la relación con EEUU. Habrá u...

Foothill Genoma

International Nuclear Information System (INIS)

Mantilla, Maria Ximena

2004-01-01

In the Colombian Institute of the Petroleum-ICP, a bioestratigrafic model is built that minimizes the risks and uncertainties in the perforation for hydrocarbons. The paper mentions the experience lived in the Well Gibraltar

African Journals Online: Suriname

African Journals Online (AJOL)

El Salvador, Equatorial Guinea, Eritrea, Estonia, Ethiopia, Faeroe Islands, Falkland Islands (Malvinas), Fiji, Finland, France, France, MEtropolitan, French Guiana, French Polynesia, French Southern Territories, Gabon, Gambia, The, Georgia, Germany, Ghana, Gibraltar, Greece, Greenland, Grenada, Guam, Guatemala ...

African Journals Online: Argentina

African Journals Online (AJOL)

El Salvador, Equatorial Guinea, Eritrea, Estonia, Ethiopia, Faeroe Islands, Falkland Islands (Malvinas), Fiji, Finland, France, France, MEtropolitan, French Guiana, French Polynesia, French Southern Territories, Gabon, Gambia, The, Georgia, Germany, Ghana, Gibraltar, Greece, Greenland, Grenada, Guam, Guatemala ...

African Journals Online: Angola

African Journals Online (AJOL)

El Salvador, Equatorial Guinea, Eritrea, Estonia, Ethiopia, Faeroe Islands, Falkland Islands (Malvinas), Fiji, Finland, France, France, MEtropolitan, French Guiana, French Polynesia, French Southern Territories, Gabon, Gambia, The, Georgia, Germany, Ghana, Gibraltar, Greece, Greenland, Grenada, Guam, Guatemala ...

African Journals Online: Netherlands

African Journals Online (AJOL)

El Salvador, Equatorial Guinea, Eritrea, Estonia, Ethiopia, Faeroe Islands, Falkland Islands (Malvinas), Fiji, Finland, France, France, MEtropolitan, French Guiana, French Polynesia, French Southern Territories, Gabon, Gambia, The, Georgia, Germany, Ghana, Gibraltar, Greece, Greenland, Grenada, Guam, Guatemala ...

African Journals Online: Mongolia

African Journals Online (AJOL)

... Faeroe Islands, Falkland Islands (Malvinas), Fiji, Finland, France, France, MEtropolitan, French Guiana, French Polynesia, French Southern Territories, Gabon, Gambia, The, Georgia, Germany, Ghana, Gibraltar, Greece, Greenland, Grenada, Guam, Guatemala, Guernsey, Guinea, Guinea-Bissau, Guyana, Haiti, Honduras ...

Browse Title Index

African Journals Online (AJOL)

Items 51 - 100 of 546 ... Vol 9, No 1 (2011), Application of Field programmable Gate Array to ... Vol 5, No 1 (2007), Barriers To Choice Of Women Occupation In ... Road Transport – Study Of Gibraltar Engineering Company, Aba, Nigeria, Abstract.

What we do | Page 90 | IDRC - International Development Research ...

International Development Research Centre (IDRC) Digital Library (Canada)

Results 891 - 900 of 1605 ... IDRC funds research in developing countries to create lasting ... Regions and countries ... --Faroe Islands, --Finland, --France, --Germany, --Gibraltar .... Carbon Market and Integrated Waste Solutions : a Case Study of Indonesia ... Topic(s): RESEARCH NETWORKS, RESEARCH METHODS, ...

Safety performance evaluation of cable median barriers on freeways in Florida.

Science.gov (United States)

Alluri, Priyanka; Haleem, Kirolos; Gan, Albert; Mauthner, John

2016-07-03

This article aims to evaluate the safety performance of cable median barriers on freeways in Florida. The safety performance evaluation was based on the percentages of barrier and median crossovers by vehicle type, crash severity, and cable median barrier type (Trinity Cable Safety System [CASS] and Gibraltar system). Twenty-three locations with cable median barriers totaling about 101 miles were identified. Police reports of 6,524 crashes from years 2005-2010 at these locations were reviewed to verify and obtain detailed crash information. A total of 549 crashes were determined to be barrier related (i.e., crashes involving vehicles hitting the cable median barrier) and were reviewed in further detail to identify crossover crashes and the manner in which the vehicles crossed the barriers; that is, by either overriding, underriding, or penetrating the barriers. Overall, 2.6% of vehicles that hit the cable median barrier crossed the median and traversed into the opposite travel lane. Overall, 98.1% of cars and 95.5% of light trucks that hit the barrier were prevented from crossing the median. In other words, 1.9% of cars and 4.5% of light trucks that hit the barrier had crossed the median and encroached on the opposite travel lanes. There is no significant difference in the performance of cable median barrier for cars versus light trucks in terms of crossover crashes. In terms of severity, overrides were more severe compared to underrides and penetrations. The statistics showed that the CASS and Gibraltar systems performed similarly in terms of crossover crashes. However, the Gibraltar system experienced a higher proportion of penetrations compared to the CASS system. The CASS system resulted in a slightly higher percentage of moderate and minor injury crashes compared to the Gibraltar system. Cable median barriers are successful in preventing median crossover crashes; 97.4% of the cable median barrier crashes were prevented from crossing over the median. Of all of

Modelling the adaptive behaviour of migrating white storks

NARCIS (Netherlands)

Shamoun-Baranes, J.; van Loon, E.E.; Bouten, W.

2006-01-01

White storks (Ciconia ciconia) are soaring migrants whose western Palearctic populations use several migration routes, concentrating mainly over Gibraltar and Israel to cross between their Palearctic breeding grounds and wintering grounds in Africa. A wealth of data has been collected during the

A set of rapid-response models for pollutant dispersion assessments in southern Spain coastal waters

International Nuclear Information System (INIS)

Perianez, R.; Caravaca, F.

2010-01-01

Three rapid-response Lagrangian particle-tracking dispersion models have been developed for southern Spain coastal waters. The three domains cover the Gulf of Cadiz (Atlantic Ocean), the Alboran Sea (Mediterranean), and the Strait of Gibraltar with higher spatial resolution. The models are based on different hydrodynamic submodels, which are run in advance. Tides are calculated using a 2D barotropic model in the three cases. Models used to obtain the residual circulation depend on the physical oceanography of each region. Thus, two-layer models are applied to Gibraltar Strait and Alboran Sea and a 3D baroclinic model is used in the Gulf of Cadiz. Results from these models have been compared with observations to validate them and are then used by the particle-tracking models to calculate dispersion. Chemical, radioactive and oil spills may be simulated, incorporating specific processes for each kind of pollutant. Several application examples are provided.

Subduction beneath Gibraltar? Recent studies provide answers

Science.gov (United States)

Gutscher, Marc-André

2012-03-01

On 1 November 1755 a powerful earthquake shook Portugal, Spain, and northern Morocco, with tremors felt across most of northwestern Europe and as far west as the Azores and as far south as the Cape Verde islands [Gutscher, 2004]. Known as the Great Lisbon Earthquake, the event was followed by a devastating tsunami that swept the nearby Atlantic coast with waves 5-15 meters high; tsunami waves 1-5 meters high were also observed in the Antilles [Gutscher et al., 2006]. Following the earthquake, huge conflagrations raged for days in the city of Lisbon, where 85% of buildings were leveled. In total, 40,000-60,000 people are estimated to have perished. Modern estimates now consider that the earthquake's magnitude was between 8.5 and 9.0, making it among the strongest earthquakes ever felt. But questions on the earthquake's exact mechanism continue to perplex researchers. Also perplexing are observations of extreme stretching of crust in the western Alboran Sea, an arm of the Mediterranean between Spain and Morocco. Could the processes that stretched the crust there be related to the forces that triggered the 1755 earthquake?

Satellite tracking of two Montagu's Harriers (Circus pygargus) : Dual pathways during autumn migration

NARCIS (Netherlands)

Trierweiler, Christiane; Koks, Ben J.; Drent, Rudi H.; Exo, Klaus-Michael; Komdeur, Jan; Dijkstra, Cor; Bairlein, Franz

2007-01-01

Autumn migration routes of two Dutch female Montagu's Harriers (Circus pygargus) were documented for the first time using satellite telemetry. Both migrated to their African wintering area-one via the Straits of Gibraltar through the Mediterranean and the other via Italy/Tunisia. The rate of travel

The Engaging Power of English-Language Promotion in Franco's Spain

DEFF Research Database (Denmark)

García, Óscar José Martín; Rodríguez Jiménez, Francisco J.

2015-01-01

The United States’ support for the Franco dictatorship, along with British dominion over Gibraltar, caused an increasing sense of frustration towards the United States and United Kingdom amongst broad sectors of the Spanish public during the 1960s and 1970s. Growing resentment towards the Anglo...

Reassurance Strategy: Incentives for Use and Conditions for Success

Science.gov (United States)

2010-03-01

making a final decision because of the scheduling chaos created by crisis-driven negotiations on the Middle East. As the holidays neared, the President...for Russian exports (below the Virgin Islands and Gibraltar). The increasing volume of Russian mineral fuel exports to the DPRK has moved Russia past

Marine exotic isopods from the Iberian Peninsula and nearby waters.

Science.gov (United States)

Martínez-Laiz, Gemma; Ros, Macarena; Guerra-García, José M

2018-01-01

Effective management of marine bioinvasions starts with prevention, communication among the scientific community and comprehensive updated data on the distribution ranges of exotic species. Despite being a hotspot for introduction due to numerous shipping routes converging at the Strait of Gibraltar, knowledge of marine exotics in the Iberian Peninsula is scarce, especially of abundant but small-sized and taxonomically challenging taxa such as the Order Isopoda. To fill this gap, we conducted several sampling surveys in 44 marinas and provide the first comprehensive study of marine exotic isopods from the Iberian Peninsula, the southern side of the Strait of Gibraltar (northern Africa) and the Balearic Islands. Exotic species included Ianiropsis serricaudis (first record for the Iberian Peninsula and Lusitanian marine province), Paracerceis sculpta (first record for the Alboran Sea ecoregion), Paradella dianae , Paranthura japonica (earliest record for the Iberian Peninsula) and Sphaeroma walkeri . Photographs with morphological details for identification for non-taxonomic experts are provided, their worldwide distribution is updated and patterns of invasion are discussed. We report an expansion in the distribution range of all species, especially at the Strait of Gibraltar and nearby areas. Ianiropsis serricaudis and Paranthura japonica are polyvectic, with shellfish trade and recreational boating being most probable vectors for their introduction and secondary spread. The subsequent finding of the studied species in additional marinas over the years points at recreational boating as a vector and indicates a future spread. We call for attention to reduce lags in the detection and reporting of small-size exotics, which usually remain overlooked or underestimated until the invasion process is at an advanced stage.

The Physical Oceanography of the Alboran Sea.

Science.gov (United States)

1987-03-01

concentrated in Lanoix, 1974) fluctuated about 38.47 ppt and 13.15’C , ie northern part (Fig. 20). Its path in the eastern basin (in situ ). Bryden et al...inclinacion transversal de las W ater. aguas atlanticas y Mediterraneas en el Estrecho de Gibraltar. Boletin del Instituto Espaiol de X1. References

The Commander’s Handbook on the Law of Naval Operations NWP 9 (REV.A)/ FMFM 1-10. Annotated Supplement

Science.gov (United States)

1989-01-01

Channel ( Luzon Strait) Geographe Channel -Maemei Sudjo Bangka Passage Gibraltar, Strait of 1.4afia-St-a:t Bangki-Strait -Greyhound Strait Ma; acca Strait...if receipt and delivery not simultaneous, two separate msgs shall be sent) F6 AS7-6- 14 FORM 21 REPORT OF SPECIAL PRIZE COMMISSIONER UNITED STATES

Caldera de recuperación de gases perdidos

OpenAIRE

Camacho Thielepape, Daniel José

2011-01-01

El objeto de este proyecto es describir las instalaciones de la caldera de recuperación de gases perdidos. Más concretamente, las instalaciones de una nueva Planta de Reciclado de Aceite Lubricante en el Campo de Gibraltar, ubicada en el Polígono Industrial del término municipal de San Roque (Cádiz).

Professor Dorothy A.E. Garrod: "Small, Dark, and Alive!"

Directory of Open Access Journals (Sweden)

Pamela Jane Smith

1997-05-01

Full Text Available In 1939, Dorothy Garrod became the first woman Professor in either Cambridge or Oxford. Garrod at the time was Director of Studies at Newnham College, Cambridge University and had been in charge of excava­tions in Gibraltar, Western Judaea, Southern Kurdistan and Mount Carmel for which she is now renowned. Trained by Marett at Oxford and Abbe Henri Breuil in France, she was one of our finest archaeologists. By 1939, Garrod had unearthed the well-preserved skull of 'Abel', a Neanderthal child, in Gibraltar, discovered and named the Natufian culture while excavating Shukba near Jerusalem, directed the long term, large scale excavations at Mount Carmel and traveled with Bruce Howe as her assistant to explore Bacho Kiro in Bulgaria. Once elected Professor, she became instrumental in establishing Archaeology and Anthropology as a full degree course and influential in Cambridge's decision to admit women to full membership in 1948. After retirement, she continued excavating in Lebanon and France. Here, with her close friend Suzanen Cassou de Saint Mathurin, she discovered the superb Magdalenian sculptured frieze at Angles-sur-l'Anglin.

The Coast Guard Proceedings of the Marine Safety & Security Council. Volume 72, Number 3, Fall 2015

Science.gov (United States)

2015-01-01

transportation and storage. Gaseous Fuels Gas is found in naturally occurring pockets of conventional gas, coal bed methane, shale gas, and tight...Institute, 2015. 6. Singapore, Suez, Panama, Hong Kong, Gibraltar, and some English Channel entrance or existing ports meet these criteria. 7. M. King...the U.S. Navy as an aviation electricians’ mate. References: Lewis, Richard J. Sr. “Calcium Oxide.” Hawley’s Condensed Chemical Dictionary , 14th

Earliest evidence of pollution by heavy metals in archaeological sites.

Science.gov (United States)

Monge, Guadalupe; Jimenez-Espejo, Francisco J; García-Alix, Antonio; Martínez-Ruiz, Francisca; Mattielli, Nadine; Finlayson, Clive; Ohkouchi, Naohiko; Sánchez, Miguel Cortés; de Castro, Jose María Bermúdez; Blasco, Ruth; Rosell, Jordi; Carrión, José; Rodríguez-Vidal, Joaquín; Finlayson, Geraldine

2015-09-21

Homo species were exposed to a new biogeochemical environment when they began to occupy caves. Here we report the first evidence of palaeopollution through geochemical analyses of heavy metals in four renowned archaeological caves of the Iberian Peninsula spanning the last million years of human evolution. Heavy metal contents reached high values due to natural (guano deposition) and anthropogenic factors (e.g. combustion) in restricted cave environments. The earliest anthropogenic pollution evidence is related to Neanderthal hearths from Gorham's Cave (Gibraltar), being one of the first milestones in the so-called "Anthropocene". According to its heavy metal concentration, these sediments meet the present-day standards of "contaminated soil". Together with the former, the Gibraltar Vanguard Cave, shows Zn and Cu pollution ubiquitous across highly anthropic levels pointing to these elements as potential proxies for human activities. Pb concentrations in Magdalenian and Bronze age levels at El Pirulejo site can be similarly interpreted. Despite these high pollution levels, the contaminated soils might not have posed a major threat to Homo populations. Altogether, the data presented here indicate a long-term exposure of Homo to these elements, via fires, fumes and their ashes, which could have played certain role in environmental-pollution tolerance, a hitherto neglected influence.

Subduction and volcanism in the Iberia-North Africa collision zone from tomographic images of the upper mantle

Science.gov (United States)

Villaseñor, Antonio; Chevrot, Sébastien; Harnafi, Mimoun; Gallart, Josep; Pazos, Antonio; Serrano, Inmaculada; Córdoba, Diego; Pulgar, Javier A.; Ibarra, Pedro

2015-11-01

New tomographic images of the upper mantle beneath the westernmost Mediterranean suggest that the evolution of the region experienced two subduction-related episodes. First subduction of oceanic and/or extended continental lithosphere, now located mainly beneath the Betics at depths greater than 400 km, took place on a NW-SE oriented subduction zone. This was followed by a slab-tear process that initiated in the east and propagated to the west, leading to westward slab rollback and possibly lower crustal delamination. The current position of the slab tear is located approximately at 4°W, and to the west of this location the subducted lithosphere is still attached to the surface along the Gibraltar Arc. Our new P-wave velocity model is able to image the attached subducted lithosphere as a narrow high-velocity body extending to shallow depths, coinciding with the region of maximum curvature of the Gibraltar Arc, the occurrence of intermediate-depth earthquakes, and anomalously thick crust. This thick crust has a large influence in the measured teleseismic travel time residuals and therefore in the obtained P-wave tomographic model. We show that removing the effects of the thick crust significantly improves the shallow images of the slab and therefore the interpretations based on the seismic structure.

Paleoseismological evidence for historical surface faulting in São Miguel island (Azores

Directory of Open Access Journals (Sweden)

Rita Carmo

2014-02-01

Full Text Available The Azores archipelago is located at the triple junction between the Eurasian, Nubian and North American lithospheric plates, whose boundaries are the Mid-Atlantic Ridge and the Azores-Gibraltar Fault Zone. São Miguel is the largest island of the archipelago and is located on the eastern part of the western segment of the Azores-Gibraltar Fault Zone. The Achada das Furnas plateau, located in the central part of the island, between Fogo and Furnas central volcanoes, is dominated by several WNW-ESE and E-W trending alignments of basaltic cinder cones. Two E-W trending scarps were identified by aerial photo interpretation. Transect trenches exposed two active normal faults-the Altiprado Faults – confirming the tectonic nature of the scarps. Several paleoearthquakes were deduced, most of which in historical times, producing 1.38 m and 0.48 m of cumulative displacement. Maximum expected magnitudes (MW determined from slip per event range from 5.7 to 6.7. One of the events probably corresponds to the historical earthquake of October 22nd, 1522, the deadliest in the archipelago. Radiocarbon ages are in agreement with this interpretation.

Wind power in the Euro-Mediterranean region: development and prospects; Energia eolica en la region euromediterranea: desarrollo y perspectivas

Energy Technology Data Exchange (ETDEWEB)

Fernandez Latorre, F. M.; Ventura Fernandez, J.

2011-07-01

This work is a first approach to wind development in the Euro-Mediterranean region and identifies the major initiatives underway as well as development conditions. It includes a study case of wind power management in the Strait of Gibraltar area. Wind development is analyzed in the Euro-Mediterranean territories by comparing Spanish regions with different States using various indicators. Key countries are noted for their potential and policies to promote wind based alternatives. (Author)

West European and East Asian Perspectives on Defense, Deterrence and Strategy. Volume 3. Spanish Perspectives on Defense, Deterrence and Strategy.

Science.gov (United States)

1984-05-16

sovereignty over the Tarfaya strip (between Western Sahara and post -colonial Morocco), over the whole of the Western Sahara and over the Spanish enclaves...veillance post , and a supply and repair vessel in the Mediterranean. Admiral of the Fleet Lewin said around the same time that the importance of Gibraltar...5.3.2 El Pais Self-appointed diario independiente de la manana. Its editorial line is controlled by Sr. Javier Pradera, former Communist Party member

The Seismic Broad Band Western Mediterranean (wm) Network and the Obs Fomar Pool: Current state and Obs activities.

Science.gov (United States)

Pazos, Antonio; Davila, Jose Martin; Buforn, Elisa; Bezzeghoud, Mourad; Harnafi, Mimoun; Mattesini, Mauricio; Caldeira, Bento; Hanka, Winfried; El Moudnib, Lahcen; Strollo, Angelo; Roca, Antoni; Lopez de Mesa, Mireya; Dahm, Torsten; Cabieces, Roberto

2016-04-01

The Western Mediterranean (WM) seismic network started in 1996 as an initiative of the Royal Spanish Navy Observatory (ROA) and the Universidad Complutense de Madrid (UCM), with the collaboration of the GeoForschungsZentrum (GFZ) of Potsdam. A first broad band seismic station (SFUC) was installed close to Cádiz (South Spain). Since then, additional stations have been installed in the Ibero-Moghrebian region. In 2005, the "WM" code was assigned by the FDSN and new partners were jointed: Evora University (UEVO, Portugal), the Scientifique Institute of Rabat (ISRABAT, Morocco), and GFZ. Now days, the WM network is composed by 15 BB stations, all of them with Streckaisen STS-2 or STS-2.5 sensors, Quanterra or Earthdata digitizers and SeiscomP. Most them have co-installed a permanent geodetic GPS stations, and some them also have an accelerometer. There are 10 stations deployed in Spanish territory (5 in the Iberian peninsula, 1 in Balearic islands and 4 in North Africa Spanish places) with VSAT or Internet communications, 2 in Portugal (one of them without real time), and 3 in Morocco (2 VSAT and 1 ADSL). Additionally, 2 more stations (one in South Spain and one in Morocco) will be installed along this year. Additionally ROA has deployed a permanent real time VBB (CMG-3T: 360s) station at the Alboran Island. Due to the fact that part of the seismic activity is located at marine areas, and also because of the poor geographic azimuthal coverage at some zones provided by the land stations (specially in the SW of the San Vicente Cape area), ROA and UCM have acquired six broad band "LOBSTERN" OBS, manufactured by KUM (Kiel, Germany), conforming the OBS FOMAR pool. Three of them with CMG-40T sensor and the other with Trillium 120. These OBS were deployed along the Gibraltar strait since January to November 2014 to study the microseismicity in the Gibraltar strait area. In September 2015 FOMAR network has been deployed in SW of the San Vicente Cape for 8 months as a part of

Early signs of geodynamic activity before the 2011–2012 El Hierro eruption

OpenAIRE

López, Carmen; García-Cañada, Laura; Martí Molist, Joan; Domínguez Cerdeña, I.

2016-01-01

The potential relation between mantle plume dynamics, regional tectonics and eruptive activity in the Canary Islands has not been studied yet through the analysis of long-time series of geophysical observational data. The existence of highly reliable seismic and geodetic data has enabled us to study from 1996 to 2014 the geodynamic evolution of the North Atlantic Azores-Gibraltar region (including the NW African margin) and its relationship with recent volcanic activity in El Hierro (Canary I...

An Approach to the Quantitative Study of Sea Floor Topography.

Science.gov (United States)

1980-01-01

Aside from the area between the ridge crest and the Iberian Peninsula (in the vicinity of the Azores-Gibraltar Ridge and Kings Trough), the...the Iberian Peninsula . This area is dominated by intermediate and high relief, probably caused by a secondary axis of spreading (Ridley et al., 1974... Climate Change in the North Pacific using Ice-Rafted Detritus as a Climatic Indicator. Geol. Soc. Amer., v. 82, p. 2741-2754. Larson, R. L. and F. N

JPRS Report, Science & Technology, USSR: Earth Sciences

Science.gov (United States)

1988-02-26

Shirshov, USSR Academy of Sciences, Moscow] lflllrtll-Inf0rTtJ;0n ^ fr" °n the morPhol°gy> ecology and propagation of aggregations of algae...42nd cruise of the research vessel "Akademik Kurchatov» between Ampere and Josephine Seamounts some 670 km to the west of the Strait of Gibraltar in...railroad roadbeds. Lithomonitoring must be carried out in many regions for ensuring the ecological purity of economic activity and protection of

Acerca de la contribución militar de la Junta General de la provincia de Guipúzcoa a la Guerra de Granada en 1484

Directory of Open Access Journals (Sweden)

García Fernández, Ernesto

2010-12-01

Full Text Available The Guipuzcoans participated with their militias and their armed men in the war against Granada waged by the Catholic Monarchs Isabella and Ferdinand, from their ascension to the throne of the Crown of Castile to the conquest of the Muslim kingdom of Granada in 1492. In this paper we look into how several requests were made from the Province of Guipuzcoa for several ships with their respective armed crews in order to control the different points of access to the Strait of Gibraltar, on the one hand, and, on the other hand, we examine the replies given by the representatives of the Province councils after the Board Meeting at Usarraga.

Los guipuzcoanos participaron con sus milicias y hombres armados en la Guerra de Granada auspiciada por los Reyes Católicos, Isabel y Fernando, desde su ascenso al trono de la Corona de Castilla hasta la conquista del reino nazarí en 1492. En este artículo se estudian por una parte las demandas a la Provincia Guipúzcoa de varias embarcaciones con sus respectivas tripulaciones armadas para controlar los accesos a Granada a través del Estrecho de Gibraltar y por otra las diversas respuestas dadas por los procuradores generales de los concejos de la Provincia, reunidos en la Junta General de Usarraga.

Earth observations during Space Shuttle Mission STS-42 - Discovery's mission to planet earth

Science.gov (United States)

Lulla, Kamlesh P.; Helfert, Michael; Amsbury, David; Pitts, David; Jaklitch, Pat; Wilkinson, Justin; Evans, Cynthia; Ackleson, Steve; Helms, David; Chambers, Mark

1993-01-01

The noteworthy imagery acquired during Space Shuttle Mission STS-42 is documented. Attention is given to frozen Tibetan lakes, Merapi Volcano in Java, Mt. Pinatubo in the Philippines, the coastline east of Tokyo Japan, land use in southern India, and the Indus River Delta. Observations of Kamchatka Peninsula, Lake Baikal, Moscow, Katmai National Park and Mt. Augustine, Alaska, the Alaskan coast by the Bering Sea, snow-covered New York, the Rhone River valley, the Strait of Gibraltar, and Mt. Ararat, Turkey, are also reported.

Modelling surface radioactive spill dispersion in the Alboran Sea

International Nuclear Information System (INIS)

Perianez, R.

2006-01-01

The Strait of Gibraltar and the Alboran Sea are the only connection between the Atlantic Ocean and the Mediterranean Sea. Intense shipping activities occur in the area, including transport of waste radionuclides and transit of nuclear submarines. Thus, it is relevant to have a dispersion model that can be used in an emergency situation after an accident, to help the decision-making process. Such dispersion model requires an appropriate description of the physical oceanography of the region of interest, with simulations of tides and residual (average) circulation. In this work, a particle-tracking dispersion model that can be used to simulate the dispersion of radionuclides in the system Strait of Gibraltar-Alboran Sea is described. Tides are simulated using a barotropic model and for the average circulation a reduced-gravity model is applied. This model is able to reproduce the main features of the Alboran circulation (the well known Western Alboran Gyre, WAG, and the coastal circulation mode). The dispersion model is run off-line, using previously computed tidal and residual currents. The contamination patch is simulated by a number of particles whose individual paths are computed; diffusion and decay being modelled using a Monte Carlo method. Radionuclide concentrations may be obtained from the density of particles per water volume unit. Results from the hydrodynamic models have been compared with observations in the area. Several examples of dispersion computations under different wind and circulation conditions are presented

Operaciones secretas inglesas en España durante la Segunda Guerra Mundial

Directory of Open Access Journals (Sweden)

Michael Alpert

2002-01-01

Full Text Available Aigunos miembros de los servicios ingleses de Información involucrados en la Guerra Civil, sobre todo Kim Philby y el capitán de Navio Hillgarth, siguieron ocupando cargos de importancia en los servicios secretos durante la Segunda Guerra Mundial. Las principales actividades de los servicios secretos ingleses en España incluían preservar la seguridad de Gibraltar, contrarrestar el trabajo de los agentes alemanes en el Estrecho, y desenmascarar a los espías españoles dirigidos por el Abwehr. Este artículo se ocupa especialmente de las dificultades de organizar el trabajo del llamado Special Operations Executive, en relación con la planificación de actividades guerrilleras y de sabotajes en caso de una ocupación de España por fuerzas militares alemanas.British specialists such as Kim Philby and Captain Alan Hillgarth, who had been involved in Intelligence services during the Spanish Civil War, contributed to the activities of the British Secret Services in Spain during the Second World War. Their main activities included the security of Gibraltar, counteracting German Intelligence in the Straits, and unmasking Spanish agents controlled by the Abwehr. This article concentrates on the particular difficulties of organising the work of the Special Operations Executive and its plans for guerrilla-type activity in the case of a German military occupation of Spain, whose neutrality, in the view of Great Britain, had to be carefully preserved.

Modelling surface radioactive spill dispersion in the Alborán Sea.

Science.gov (United States)

Periáñez, R

2006-01-01

The Strait of Gibraltar and the Alborán Sea are the only connection between the Atlantic Ocean and the Mediterranean Sea. Intense shipping activities occur in the area, including transport of waste radionuclides and transit of nuclear submarines. Thus, it is relevant to have a dispersion model that can be used in an emergency situation after an accident, to help the decision-making process. Such dispersion model requires an appropriate description of the physical oceanography of the region of interest, with simulations of tides and residual (average) circulation. In this work, a particle-tracking dispersion model that can be used to simulate the dispersion of radionuclides in the system Strait of Gibraltar-Alborán Sea is described. Tides are simulated using a barotropic model and for the average circulation a reduced-gravity model is applied. This model is able to reproduce the main features of the Alborán circulation (the well known Western Alborán Gyre, WAG, and the coastal circulation mode). The dispersion model is run off-line, using previously computed tidal and residual currents. The contamination patch is simulated by a number of particles whose individual paths are computed; diffusion and decay being modelled using a Monte Carlo method. Radionuclide concentrations may be obtained from the density of particles per water volume unit. Results from the hydrodynamic models have been compared with observations in the area. Several examples of dispersion computations under different wind and circulation conditions are presented.

Coste de la limpieza “cotidiana” de playas

OpenAIRE

Patricio, Poullet; Juan J., Muñoz-Perez; Gregorio, Gomez-Pina; Angel, de la Casa; Jorge, Roman-Sierra; Marina, Navarro Pons

2015-01-01

Más de 90.000 buques mercantes al año cruzan el Estrecho de Gibraltar de los que aproximadamente un 5% son petroleros. Ello, conjuntamente con la existencia de varios puertos con refinerías y polígonos industriales petroquímicos y la práctica del bunkering para aprovisionamiento de combustible, hace a la costa gaditana un punto de riesgo para la contaminación por hidrocarburos (Carmona et al., 2009). La Demarcación de Costas de Andalucía-Atlántico (DCAA), dependiente del Ministerio de Agricul...

Atlas de Riesgo Ambiental Aplicado en Marinas del Espacio SUDOE

OpenAIRE

Avendaño Castro, Pablo A.

2016-01-01

RESUMEN: Se analizan 418 marinas del sudoeste europeo utilizando una metodología de evaluación de riesgo ambiental diseñada en el IH Cantabria por Gómez et al. (2016). La zona de estudio es la zona costera del área elegible SUDOE y la región de la Macaronesia, comprendiendo las naciones de Francia (sudoeste), España, Portugal y Reino Unido (Gibraltar). Se obtiene el valor del riesgo ambiental a partir de la estimación de las consecuencias (factores de navegación, dragado y entorno), vulnerabi...

El papel de España en la derrota de la Alemania nazi durante la Segunda Guerra Mundial

Directory of Open Access Journals (Sweden)

Bertram M. GORDON

2010-02-01

Full Text Available RESUMEN: La importancia del papel jugado por España en la derrota de la Alemania nazi muy a menudo ha sido infravalorada por los historiadores. Con su victoria sobre Francia, en junio de 1940, Alemania tuvo la oportunidad de extender su poder por España, Gibraltar, a través del Mediterráneo hacia el norte de África, por la costa occidental africana, y posiblemente hacia el Atlántico sur y hacia Sudamérica. De este modo, Gran Bretaña podría haberse visto obligada a retirarse de la guerra. Sin embargo, Hitler y su mando militar se vieron sorprendidos por su rápida y completa victoria en Francia, y no contaban con un plan de continuación que no fuese esperar la rendición del Reino Unido. Cuando de forma gradual, en los meses de julio y agosto, Hitler y sus consejeros empezaron a considerar las ventajas que les supondría conquistar Gibraltar e incorporar a España en la guerra, ya habían firmado el armisticio con Francia, seducidos por la idea de futuros emplazamientos en África, a expensas de los intereses españoles. Ello hizo que Hitler no tuviese mucho que ofrecer a Franco cuando se reunieron en Hendaya en octubre de 1940. El papel jugado por Franco en Hendaya para mantener a España fuera de la guerra fue menos significativo de lo que se ha sugerido. De hecho, Franco se comprometió en Hendaya a entrar en la guerra, y sólo después de febrero de 1941 hizo todo lo posible para mantener a España fuera del conflicto. La historia de las oportunidades perdidas por Alemania en 1940 resalta la importancia que tuvo España en la dirección que tomó la guerra. Palabras Clave: Segunda Guerra Mundial, estrategia de guerra, España, Francisco Franco, Adolfo Hitler. ABSTRACT: The importance of Spain's role in the defeat of Nazi Germany has been too frequently overlooked by historians. With their victory over France in June 1940, Germany gained an opportunity to extend its power into Spain, Gibraltar, across the Mediterranean into North

Las relaciones hispano- norteamericanas durante la presidencia de L. B. Johnson: 1964- 1968

Directory of Open Access Journals (Sweden)

Rosa María PARDO SANZ

2010-02-01

Full Text Available RESUMEN: La renegociación en 1963 de los acuerdos hispano-norteamericanos firmados en 1953 no resultó satisfactoria para la parte española y dejó en evidencia la debilidad negociadora del Régimen de Franco. Sin embargo, abrió una nueva etapa en las relaciones bilaterales marcada por la cooperación diplomática y militar, un incremento en las relaciones económicas y un creciente flujo de intercambio cultural. Desde España se buscó no chocar con los intereses de Washington, aunque resultó cada vez más difícil (Cuba, Marruecos, OTAN, política árabe o Gibraltar, conforme la mejora de la posición económica e internacional de España y el nuevo clima de distensión internacional dejaron margen para una política exterior española más independiente. A partir de 1966, en paralelo con la reivindicación de Gibraltar, hubo un giro nacionalista de la política exterior española que se manifestó en una mayor exigencia y control sobre las relaciones bilaterales. Una actitud nueva que culminará en la renegociación de 1968. Respecto al tema político, la prudente política norteamericana de cooperar con el Régimen para garantizar el uso de las bases y, a un tiempo, mantener abierto el diálogo con la oposición de cara a una próxima transición, se demostró cada vez más ineficaz conforme el antiamericanismo comenzó a convertirse, desde 1967-68, en uno de los pocos elementos comunes de la oposición antifranquista. Palabras clave: Relaciones España-Estados Unidos, política exterior, historia militar, Franquismo, Guerra Fría. SUMMARY: In 1963, the renewal of the U.S-Spanish Executive Agreements (signed in 1953 was not satisfactory for the Spanish Government and revealed the political weakness of the Franco’s Regimen. However, a new period in the bilateral relationship was opened: an increase of diplomatic and military cooperation, economic relations and cultural links. The intention of the Spanish Government was avoiding any

Moluscos Poliplacóforos del litoral atlántico del sur de la Península Ibérica

Directory of Open Access Journals (Sweden)

Carmona Zalvide, M. P.

2000-12-01

Full Text Available In this paper, an updated check-list of the polyplacophoran species from Sagres (Portugal to Strait of Gibraltar is present. Twenty taxa are recorded in this area: Lepidopleurus cajetanus, Leptochiton cancellatus, Leptochiton algesirensis, Leptochiton scabridus, Callochiton septemvalvis, Callochiton euplaeae, Lepidochitona cinerea, Lepidochitona corrugata, Lepidochitona canariensis, Lepidochitona monterosatoi, Lepidochitona kaasi, Lepidochitona severianoi, Chaetopleura angulata, Ischnochiton rissoi, Chiton olivaceus, Chiton corallinus, Chiton phaesolinus, Acanthochitona fascicularis and Acanthochitona crinita. From these species, Lepidochitona canariensis, L simrothi, Callochiton septemvalvis and Lepidochitona monterosatoi amplify their geographical distribution to Southern Atlantic coast of southern Iberian Peninsula.

Se aporta el catálogo de los Moluscos Poliplacóforos de las costas atlánticas del sur de la Península Ibérica, desde Sagres (Portugal hasta Gibraltar. Se cita un total de 20 taxones (Lepidopleurus cajetanus, Leptochiton cancellatus, Leptochiton algesirensis, Leptochiton scabridus, Callochiton septemvalvis, Callochiton euplaeae, Lepidochitona cinerea, Lepidochitona corrugata, Lepidochitona canariensis, Lepidochitona monterosatoi, Lepidochitona kaasi, Lepidochitona severianoi, Chaetopleura angulata, Ischnochiton rissoi, Chiton olivaceus, Chiton corallinus, Chiton phaesolinus, Acanthochitona fascicularis y Acanthochitona crinita todos ellos pertenecientes al dominio litoral. La captura de Lepidochitona canariensis y L. simrothi en aguas atlánticas ibéricas constituye la primera cita para el suratlántico ibérico. A su vez se amplía la distribución a esta zona de Callochiton septemvalvis y de Lepidochitona monterosatoi.

Shear velocity model for the westernmost Mediterranean from ambient noise and ballistic finite-frequency Rayleigh wave tomography

Science.gov (United States)

Palomeras, I.; Villasenor, A.; Thurner, S.; Levander, A.; Gallart, J.; Harnafi, M.

2014-12-01

The westernmost Mediterranean comprises the Iberian Peninsula and Morocco, separated by the Alboran Sea and the Algerian Basin. From north to south this region consists of the Pyrenees, resulting from Iberia-Eurasia collision; the Iberian Massif, which has been undeformed since the end of the Paleozoic; the Central System and Iberian Chain, regions with intracontinental Oligocene-Miocene deformation; the Gibraltar Arc (Betics, Rif and Alboran terranes), resulting from post-Oligocene subduction roll-back; and the Atlas Mountains. We analyzed data from recent broad-band array deployments and permanent stations in the area (IberArray and Siberia arrays, the PICASSO array, the University of Munster array, and the Spanish, Portuguese and Moroccan National Networks) to characterize its lithospheric structure. The combined array of 350 stations has an average interstation spacing of ~60 km. We calculated the Rayleigh waves phase velocities from ambient noise (periods 4 to 40 s) and teleseismic events (periods 20 to 167 s). We inverted the phase velocities to obtain a shear velocity model for the lithosphere to ~200 km depth. Our results correlate well with the surface expression of the main structural units with higher crustal velocity for the Iberian Massif than for the Alpine Iberia and Atlas Mountains. The Gibraltar Arc has lower crustal shear velocities than the regional average at all crustal depths. It also shows an arc shaped anomaly with high upper mantle velocities (>4.6 km/s) at shallow depths (volcanic fields in Iberia and Morocco, indicative of high temperatures at relatively shallow depths, and suggesting that the lithosphere has been removed beneath these areas.

Alalia & the Aftermath

Directory of Open Access Journals (Sweden)

Gregory Douglas Wear

2016-11-01

Full Text Available The battle at Alalia mentioned by Herodotos has long been at the centre of debate with regards to a potential ‘Carthaginian Blockade’ of the Straits of Gibraltar, perhaps preventing the Phokaian Greeks from entering the Atlanticand its coastal markets. There are further ancient sources which directly or indirectly give clues to Alalia, its circumstances and its aftermath. The battle may have had an impact on the Phokaian Greeks’ freedom of movement in that they chose not to attempt to sail through the Straits of Gibraltar, all the more as the northern markets could be reached via inland routes along the streams that, albeit with some expensive overland transport in between, connected the Mediterranean with the Atlantic. Their concentration around the mouth of the Rhône facilitated the Greek trade in e.g. tin from the north, without the need to engage the Carthaginians, if the latter indeed controlled maritime traffic to and from the Mediterraneanat the Straits. Although they may have retreated from Alalia, and the Carthaginians, as before, controlled the seas west of Empùries, the Phokaian Greeks did not withdraw from the Tyrrhenian Seaor the western Mediterranean altogether, but remained influential and prosperous in the area, even if Massalia experienced a period of economic decline. As such, the result of the battle at Alalia, regardless of whether it was a Greek victory or defeat, had little impact on the balance of power in the western Mediterraneanaround the middle of the first millennium BCE.

The reactivation of the SW Iberian passive margin: a brief review

Science.gov (United States)

Duarte, Joao; Rosas, Filipe; Terrinha, Pedro; Schellart, Wouter; Almeida, Pedro; Gutscher, Marc-André; Riel, Nicolas; Ribeiro, António

2016-04-01

On the morning of the 1st of November of 1755 a major earthquake struck offshore the Southwest Iberian margin. This was the strongest earthquake ever felt in Western Europe. The shake, fire and tsunami devastated Lisbon, was felt as far as Finland and had a profound impact on the thinkers of that time, in particular on the Enlightenment philosophers such as Voltaire, Rousseau and Kant. The Great Lisbon Earthquake is considered by many as the event that marks the birth of modern geosciences; and made of this region one of the most well studied areas in the world. After the 1755 earthquake, Kant and others authors wrote several treaties dealing with the causes and dynamics of earthquakes and tsunamis and were close to identify some key elements of what we now call plate tectonics. More than two hundred years later, in the year of 1969, the region was struck by another major earthquake. This was precisely during the period in which the theory of plate tectonics was being built. Geoscientists like Fukao (1973), Purdy (1975) and Mackenzie (1977) immediately focused their attention in the area. They suggested that these events were related with "transient" subduction of Africa below Iberia, along the East-West Azores-Gibraltar plate boundary. Several years later, Ribeiro (1989) suggested that instead of Africa being subducted below Iberia, it was the West Iberian passive margin that was being reactivated, a process that may, in time, lead to the formation of a new subduction zone. In the turning of the millennium, a subducting slab was imaged bellow the Gibraltar Straits, a remanent of the Western Mediterranean arc system that according to Gutscher et al. (2002) was related with ongoing subduction. Recently, it was proposed that a causal link between the Gibraltar subduction system and the reactivation of the SW Iberian margin might exist. In addition, the large-scale Africa-Eurasia convergence is inducing compressive stresses along the West Iberian margin. The margin

Narrar historias, desbordar fronteras

Directory of Open Access Journals (Sweden)

Pérez, Marta

2015-12-01

Full Text Available This paper presents the ethnographic experience of the author, who worked as an independent researcher in the Project «The Human Cost of Border Control» led by the Free University of Amsterdam. More concretely, the narrative follows her participation in the making of a database with the available information about the death of those immigrants who died in their trip to Europe, and whose bodies were rescuedeither in the sea or in the coast of Spain, Malta, Italy, Greece and Gibraltar. Through the description of the participation on this project, the author leads the reader to some of the black holes of contemporary migratory flows, inscribed in the bureaucracies of death, in the statistical voids, and in public silence.Este artículo narra la experiencia etnográfica de la autora como investigadora independiente para el proyecto «The Human Cost of Border Control» de la Universidad Libre de Ámsterdam. Más en concreto, la línea argumental se basa en su participación en la construcción de una base de datos de defunción de las personas que perdieron la vida en su viaje a Europa, y cuyos cuerpos se habían rescatado en el mar o encontrado en las costas de España, Malta, Italia, Grecia y Gibraltar. A partir de su participación en este proyecto, nos desvela algunos de los agujeros negros de la emigración, incluyendo las burocracias de la muerte, los vacíos estadísticos, y los silencios públicos.

Del desastre de Getares a la victoria del Salado : la crítica situación de la zona del Estrecho en 1340

Directory of Open Access Journals (Sweden)

Manuel López Fernández

2007-01-01

Full Text Available A comienzos de 1340 se presagiaba en el Estrecho de Gibraltar una ofensiva meriní. Castilla contaba con una flota insuficiente para frenar a los musulmanes y el reino de Aragón, que también colaboraba en la vigilancia de aquellas aguas, había reducido sus efectivos al mínimo. Así las cosas, en el mes de abril la flota castellano-aragonesa sufrió una aplastante derrota en la Ensenada de Getares, a la que siguió el traslado de un importante contingente marroquí a la Península y el posterior cerco a Tarifa. Alfonso XI, con la ayuda del rey de Portugal, acudió a descercar esta plaza y acabó imponiéndose en la batalla del Salado. Las consecuencias posteriores de esta victoria resultaron fundamentales para el dominio del Estrecho.At the beginning of 1340, a Merini attack was expected in the Straits of Gibraltar. The kingdom of Castile had an inadequate navy to stop the Muslims, and the Aragón’s kingdom, which also helped in the surveillance of that sea area, had reduced his troops to the minimum. In April, the Castilian - Aragonese navy suffered a crushing defeat in the Getares inlet, followed by the pass of one important Moroccans’ contingent to the Peninsula and the later siege to Tarifa. Alfonso XI, with the help of the King of Portugal, came to free the city from the siege, and later on he won the Salado Battle. The subsequent consequences of this victory were essential for the Straits control.

Finite-frequency Rayleigh wave tomography of the western Mediterranean: Mapping its lithospheric structure

Science.gov (United States)

Palomeras, I.; Thurner, S.; Levander, A.; Liu, K.; Villasenor, A.; Carbonell, R.; Harnafi, M.

2014-01-01

We present a 3-D shear wave velocity model for the crust and upper mantle of the western Mediterranean from Rayleigh wave tomography. We analyzed the fundamental mode in the 20-167 s period band (6.0-50.0 mHz) from earthquakes recorded by a number of temporary and permanent seismograph arrays. Using the two-plane wave method, we obtained phase velocity dispersion curves that were inverted for an isotropic Vs model that extends from the southern Iberian Massif, across the Gibraltar Arc and the Atlas mountains to the Saharan Craton. The area of the western Mediterranean that we have studied has been the site of complex subduction, slab rollback, and simultaneous compression and extension during African-European convergence since the Oligocene. The shear velocity model shows high velocities beneath the Rif from 65 km depth and beneath the Granada Basin from ˜70 km depth that extend beneath the Alboran Domain to more than 250 km depth, which we interpret as a near-vertical slab dangling from beneath the western Alboran Sea. The slab appears to be attached to the crust beneath the Rif and possibly beneath the Granada Basin and Sierra Nevada where low shear velocities (3.8 km/s) are mapped to >55 km depth. The attached slab is pulling down the Gibraltar Arc crust, thickening it, and removing the continental margin lithospheric mantle beneath both Iberia and Morocco as it descends into the deeper mantle. Thin lithosphere is indicated by very low upper mantle velocities beneath the Alboran Sea, above and east of the dangling slab and beneath the Cenozoic volcanics.

On the Mediterranean Sea inter-basin exchanges and nutrient dynamics

Science.gov (United States)

Rupolo, V.; Ribera D'Alcalà, M.; Iudicone, D.; Artale, V.

2009-04-01

The Mediterranean Sea is an evaporative basin in which the deficit of water is supplied by the inflow from the Gibraltar Strait of Atlantic Water. The net result of the air sea interactions in the entire basin is an outflow at Gibraltar of a salty water that is mainly constituted by the Levantin Intermediate Water, formed in the eastern part of the basin. Despite this simplified pattern, the circulation in the Mediterranean is rather complex. Most of the Mediterranean sub-basins are characterized by water mass formation processes and the presence of sills and straits strongly influence both the spreading and the mixing of intermediate and deep waters. In this context a Lagrangian diagnostics applied to numerical results was used to quantify mass transport in the main pathways of the upper and lower cells of the Mediterranean thermohaline circulation as they results from OGCM simulations. Lagrangian diagnostics reveals to be very useful to quantify both transports between different regions and the associated spectrum of transit times by means of pdf distribution of particles transit times between the different regions of the basin. This method is very effective to estimate the contribution of different water masses in isopycnal and diapycnal transformation processes and in reconstructing the fate of tracers. We use here these previous results on the basin circulation for better understanding the nutrient dynamics within the basin where the inputs from the different sources (atmosphere, runoff and open ocean) have similar order of magnitude. This, to the aim of building scenarios on the impact of climate driven changes in elemental fluxes to the basin on the internal nutrient dynamics.

LES SUBSAHARIENS ENTRE TRANSIT AU MAROC ET IMMIGRATION CLANDESTINE EN ESPAGNE

Directory of Open Access Journals (Sweden)

Ali Faleh

2009-01-01

Full Text Available La migración irregular llega a ser la forma dominante de los flujos migratorios con destino a los países de la Unión Europea, y altera las relaciones entre las dos riveras del Estrecho de Gibraltar: Marruecos y España. El presente artículo aborda el análisis del fl ujo migratorio subsahariano en tránsito por Marruecos, la descripción del perfil sociodemográfico de los migrantes, así como el conocimiento de los motivos de partida, itinerarios y condiciones de vida en Marruecos de los retornados subsaharianos así como sus aspiraciones.

Análisis de la percepción turística en la región Tánger-Tetuán (Marruecos

Directory of Open Access Journals (Sweden)

José Antonio López Sánchez

2014-01-01

Full Text Available Este artículo analiza la actividad turística en la región Tánger-Tetuán (Marruecos. Para ello entre otras acciones se ha realizado un estudio de las principales variables estadísticas disponibles en la zona, un trabajo de campo enmarcado dentro del proyecto de investigación sobre turismo sostenible denominado Ibn Battouta y la realización de una encuesta entre los principales sectores relacionados son las herramientas utilizadas. En este análisis se comparan los valores de la región con otras áreas cercanas dentro del Estrecho de Gibraltar.

La uia Heraclea en el Occidente: mito, arqueología, propaganda, historia

Directory of Open Access Journals (Sweden)

Robert C. Knapp

1986-06-01

Full Text Available The uia Heraclea is investigated as a mythical, archeological and historical reality. From the myth of Heracles and the cattle of Geryon in the West developed a tradition of a uia Heraclea which can be traced, through literary allusions, along a land route from the Straits of Gibraltar to Italy. As would be expected from its mythical nature, archaeology does not show many traces of the uia Heraclea; however the mythical tradition of Heracles in Iberia and Gaul is utilized by historical figures such as Hannibal and, most importantly, Augustus, to illustrate and extol their own deeds of conquest and greatness in the West.

Tendencias y perspectivas del turismo de sol y playa en Marruecos. El caso de la región Tánger-Tetuán

Directory of Open Access Journals (Sweden)

López Sánchez, José Antonio

2012-08-01

Full Text Available The aim pursued in this paper is to analyze the tourism activity of the region Tangier- Tetouan in Morocco. In addition to the study of the main available variables statistics for the region, a fieldwork has been carried out in the framework of an extensive research project on sustainable tourism, called Ibn Battouta. The values of the region have been compared with the values of other nearby areas in the Strait of Gibraltar. As a result of the analysis performed, the tourist potential of the region has been confirmed, including the sun and beach tourism. The current global situation has raised a number of questions and queries about the tendency of this activity in Morocco. Moroccan government has clearly opted for schemes —such as the called Plan Azur— for the sector. The development of the tourism activity should also be accompanied by improving environmental parameters that have been affected by some of the actions taken in the coast of Tangier-Tetouan Region.

Este artículo pretende analizar la actividad turística en la región Tánger-Tetuán en Marruecos. Además del estudio de las principales variables estadísticas disponibles en la zona, se ha realizado un trabajo de campo enmarcado dentro de un proyecto de investigación más amplio sobre turismo sostenible denominado Ibn Battouta. Se comparan los valores de la región con otras áreas cercanas dentro del estrecho de Gibraltar. En este análisis se constata el potencial turístico de la región. El gobierno marroquí ha apostado de forma evidente por el sector con planes como el “Plan Azur”. Su desarrollo debe ir paralelo a la mejora de los parámetros medioambientales que se han visto afectados por algunas de las actuaciones realizadas en la costa de dicha región. [fr] Cet article analyse l'activité touristique dans la région Tanger-Tétouan au Maroc. En outre l'étude des principales variables statistiques dans la zone, nous avons réalisé en travail sur le

Understanding the unique biogeochemistry of the Mediterranean Sea: Insights from a coupled phosphorus and nitrogen model

Science.gov (United States)

Powley, Helen R.; Krom, Michael D.; Van Cappellen, Philippe

2017-06-01

The Mediterranean Sea (MS) is an oligotrophic basin whose offshore water column exhibits low dissolved inorganic phosphorus (P) and nitrogen (N) concentrations, unusually high nitrate (NO3) to phosphate (PO4) ratios, and distinct biogeochemical differences between the Western Mediterranean Sea (WMS) and Eastern Mediterranean Sea (EMS). A new mass balance model of P and N cycling in the WMS is coupled to a pre-existing EMS model to understand these biogeochemical features. Estimated land-derived inputs of reactive P and N to the WMS and EMS are similar per unit surface area, but marine inputs are 4 to 5 times greater for the WMS, which helps explain the approximately 3 times higher primary productivity of the WMS. The lateral inputs of marine sourced inorganic and organic P support significant fractions of new production in the WMS and EMS, similar to subtropical gyres. The mass balance calculations imply that the MS is net heterotrophic: dissolved organic P and N entering the WMS and EMS, primarily via the Straits of Gibraltar and Sicily, are mineralized to PO4 and NO3 and subsequently exported out of the basin by the prevailing anti-estuarine circulation. The high deepwater (DW) molar NO3:PO4 ratios reflect the high reactive N:P ratio of inputs to the WMS and EMS, combined with low denitrification rates. The lower DW NO3:PO4 ratio of the WMS (21) compared to the EMS (28) reflects lower reactive N:P ratios of inputs to the WMS, including the relatively low N:P ratio of Atlantic surface water flowing into the WMS.Plain Language SummaryThe Mediterranean Sea (MS) is a marine desert: it exhibits extremely low biological productivity despite being almost entirely surrounded by land with high nutrient loadings from a large coastal population. To explain this paradox, we analyze the sources and fate of the two main nutrient elements that support the production of marine biomass, phosphorus (P), and nitrogen (N). We find that the main source of P and N to the MS is inflow

Evidence of Multimodal Structure of the Baroclinic Tide in the Strait of Gibraltar

National Research Council Canada - National Science Library

Vazquez, A; Stashchuk, N; Vlasenko, V; Bruno, M; Izquierdo, A; Gallacher, P. C

2006-01-01

.... Analysis of the empirical orthogonal functions of the ADCP measurements performed over CS and model time series has shown that the second baroclinic mode predominates in the second type of internal wave. Its amplitude can reach one-third that of the first baroclinic mode of the leading waves of depression.

Investigating Miocene Mediterranean-Atlantic Gateway Exchange (IMMAGE) - an amphibious drilling proposal

Science.gov (United States)

Flecker, Rachel

2017-04-01

Today Mediterranean seawater flows out through the Gibraltar Straits, forming a saline plume at intermediate depths in the Atlantic. The plume's sedimentary record of distinctive, contouritic deposits has recently been recovered during IODP Leg 339 in the Gulf of Cadiz documenting a Mediterranean contribution to Atlantic thermohaline circulation since the Pliocene. However, before the Pliocene, the conduit for Mediterranean-Atlantic exchange is unclear. Gibraltar may have already been open, but two additional marine corridors also existed through northern Morocco and southern Spain. The restriction and closure of these Miocene connections resulted in extreme salinity fluctuations in the Mediterranean, leading to the precipitation of thick evaporites. This event is known as the Messinian Salinity Crisis (MSC) and recovering a complete record of the MSC is the target of current IODP drilling proposals (e.g. DREAM). Understanding both the causes of high-amplitude salinity change in the Mediterranean and its global consequences for thermohaline circulation in the Atlantic is dependent on recovering a complete record of Mediterranean-Atlantic exchange before, during and after the MSC. This key objective of the IMMAGE drilling proposal requires core recovery on-shore at the mouths of the Betic and Rifian corridors which are now exposed on land, as well as offshore, in the Alborán Sea and on the Atlantic continental margin. Consequently to meet this objective, an amphibious drilling strategy is necessary, involving both IODP and ICDP targets. In addition to allowing us to reconstruct Mediterranean-Atlantic exchange during high amplitude salinity fluctuations and identify the conduit through which exchange occurred, the sediments recovered from IMMAGE drilling will also provide us with a unique and explicit test for ocean physics hypotheses describing the location, size and velocity of overflow plumes under conditions where the density contrast between the two water

Honey buzzards don't always make a beeline.

Science.gov (United States)

Chapman, Jason W

2017-03-01

(a) European honey buzzards breeding in Western Europe primarily use soaring flight to make annual long-range migrations via the Strait of Gibraltar to winter in West Africa; this adult male was photographed on migration near Gibraltar. Photo: Javier Elloriaga. (b) Autumn migration routes of 12 satellite tagged adult European honey buzzards (colour-coded lines); compared with the shortest possible straight-line routes (dashed lines), most routes involved substantial westerly detours in Africa. Adapted from Vansteelant et al. (2016). (c) In contrast, Montagu's harriers predominantly use flapping flight during their migrations; this adult male is carrying a satellite transmitter. Photo: Theo van Kooten. (d) Autumn migration routes of 34 satellite tagged adult Montagu's harriers; migratory tracks more closely approached straight-line routes, and typically involved longer sea crossings, than seen in European honey buzzards. Adapted from Trierweiler et al. (). In Focus: Vansteelant, W.M.G., Shamoun-Baranes, J., van Manen, W., van Diermen, J. & Bouten, W. (2017) Seasonal detours by soaring migrants shaped by wind regimes along the East Atlantic Flyway. Journal of Animal Ecology, 86, 179-191. Migratory birds often make substantial detours from the shortest possible route during their annual migrations, which may potentially increase the duration and energetic cost of their journeys. Vansteelant et al. () investigate repeated migrations of adult European honey buzzards between the Netherlands and sub-Saharan Africa, and find that they make large westerly detours in Africa on both the spring and autumn routes. These detours allow migrants to capitalise on more favourable winds further along the route, thus reducing energy expenditure. Lifelong tracking studies will allow researchers to identify how migration routes have evolved to exploit predictable atmospheric and oceanic circulation patterns. © 2017 The Author. Journal of Animal Ecology © 2017 British Ecological

Synthetic tsunami waveform catalogs with kinematic constraints

Science.gov (United States)

Baptista, Maria Ana; Miranda, Jorge Miguel; Matias, Luis; Omira, Rachid

2017-07-01

In this study we present a comprehensive methodology to produce a synthetic tsunami waveform catalogue in the northeast Atlantic, east of the Azores islands. The method uses a synthetic earthquake catalogue compatible with plate kinematic constraints of the area. We use it to assess the tsunami hazard from the transcurrent boundary located between Iberia and the Azores, whose western part is known as the Gloria Fault. This study focuses only on earthquake-generated tsunamis. Moreover, we assume that the time and space distribution of the seismic events is known. To do this, we compute a synthetic earthquake catalogue including all fault parameters needed to characterize the seafloor deformation covering the time span of 20 000 years, which we consider long enough to ensure the representability of earthquake generation on this segment of the plate boundary. The computed time and space rupture distributions are made compatible with global kinematic plate models. We use the tsunami empirical Green's functions to efficiently compute the synthetic tsunami waveforms for the dataset of coastal locations, thus providing the basis for tsunami impact characterization. We present the results in the form of offshore wave heights for all coastal points in the dataset. Our results focus on the northeast Atlantic basin, showing that earthquake-induced tsunamis in the transcurrent segment of the Azores-Gibraltar plate boundary pose a minor threat to coastal areas north of Portugal and beyond the Strait of Gibraltar. However, in Morocco, the Azores, and the Madeira islands, we can expect wave heights between 0.6 and 0.8 m, leading to precautionary evacuation of coastal areas. The advantages of the method are its easy application to other regions and the low computation effort needed.

Lithospheric structure of the westernmost Mediterranean inferred from finite frequency Rayleigh wave tomography S-velocity model.

Science.gov (United States)

Palomeras, Imma; Villasenor, Antonio; Thurner, Sally; Levander, Alan; Gallart, Josep; Harnafi, Mimoun

2016-04-01

The Iberian Peninsula and Morocco, separated by the Alboran Sea and the Algerian Basin, constitute the westernmost Mediterranean. From north to south this region consists of the Pyrenees, the result of interaction between the Iberian and Eurasian plates; the Iberian Massif, a region that has been undeformed since the end of the Paleozoic; the Central System and Iberian Chain, regions with intracontinental Oligocene-Miocene deformation; the Gibraltar Arc (Betics, Rif and Alboran terranes) and the Atlas Mountains, resulting from post-Oligocene subduction roll-back and Eurasian-Nubian plate convergence. In this study we analyze data from recent broad-band array deployments and permanent stations on the Iberian Peninsula and in Morocco (Spanish IberArray and Siberia arrays, the US PICASSO array, the University of Munster array, and the Spanish, Portuguese, and Moroccan National Networks) to characterize its lithospheric structure. The combined array of 350 stations has an average interstation spacing of ~60 km, comparable to USArray. We have calculated the Rayleigh waves phase velocities from ambient noise for short periods (4 s to 40 s) and teleseismic events for longer periods (20 s to 167 s). We inverted the phase velocities to obtain a shear velocity model for the lithosphere to ~200 km depth. The model shows differences in the crust for the different areas, where the highest shear velocities are mapped in the Iberian Massif crust. The crustal thickness is highly variable ranging from ~25 km beneath the eastern Betics to ~55km beneath the Gibraltar Strait, Internal Betics and Internal Rif. Beneath this region a unique arc shaped anomaly with high upper mantle velocities (>4.6 km/s) at shallow depths (volcanic fields in Iberia and Morocco, indicative of high temperatures at relatively shallow depths, and suggesting that the lithosphere has been removed beneath these areas

About the seasonal variability of the Alboran Sea circulation

Science.gov (United States)

Vargas-Yáñez, M.; Plaza, F.; García-Lafuente, J.; Sarhan, T.; Vargas, J. M.; Vélez-Belchi, P.

2002-07-01

Data from a mooring line deployed midway between the Alboran Island and Cape Tres Forcas are used to study the time variability of the Alboran Sea from May 1997 to May 1998. The upper layer salinity and zonal velocity present annual and semiannual cycles characterised by a minimum in spring and autumn and a maximum in summer and winter. Temperature has the opposite behaviour to that of salinity indicating changes in the presence of the Atlantic water within the Alboran Passage. A large set of SST images is used to study these cycles. The decrease of salinity and velocity in our mooring location in spring and autumn seems to be related to the eastward drifting of the Western Alboran Gyre (WAG). The increase of salinity and velocity is caused by the Atlantic current flowing south of the Alboran Island and its associated thermohaline front. Conductivity-temperature-depth (CTD) data from two cruises along the 3°W are coherent with current meters and SST interpretations. During the period analysed, summer months are characterised by the stability of the two-gyre system, while in winter, the circulation is characterised by a coastal jet flowing close to the African shore. We use sea level differences across the Strait of Gibraltar for studying the variability of the Atlantic inflow. We discuss the changes in the Alboran Sea circulation and its relation with the variability of the inertial radius of the Atlantic inflow. Though our results are speculative, we find a possible relation between the disappearance of the two-gyre system and a reversal of the circulation in Gibraltar. Longer time series are needed to conclude, but comparison with previous works makes us think that the seasonal cycle described from May 1997 to May 1998 could be the most likely one for the Alboran Sea upper layer.

Birds of a feather: Neanderthal exploitation of raptors and corvids.

Science.gov (United States)

Finlayson, Clive; Brown, Kimberly; Blasco, Ruth; Rosell, Jordi; Negro, Juan José; Bortolotti, Gary R; Finlayson, Geraldine; Sánchez Marco, Antonio; Giles Pacheco, Francisco; Rodríguez Vidal, Joaquín; Carrión, José S; Fa, Darren A; Rodríguez Llanes, José M

2012-01-01

The hypothesis that Neanderthals exploited birds for the use of their feathers or claws as personal ornaments in symbolic behaviour is revolutionary as it assigns unprecedented cognitive abilities to these hominins. This inference, however, is based on modest faunal samples and thus may not represent a regular or systematic behaviour. Here we address this issue by looking for evidence of such behaviour across a large temporal and geographical framework. Our analyses try to answer four main questions: 1) does a Neanderthal to raptor-corvid connection exist at a large scale, thus avoiding associations that might be regarded as local in space or time?; 2) did Middle (associated with Neanderthals) and Upper Palaeolithic (associated with modern humans) sites contain a greater range of these species than Late Pleistocene paleontological sites?; 3) is there a taphonomic association between Neanderthals and corvids-raptors at Middle Palaeolithic sites on Gibraltar, specifically Gorham's, Vanguard and Ibex Caves? and; 4) was the extraction of wing feathers a local phenomenon exclusive to the Neanderthals at these sites or was it a geographically wider phenomenon?. We compiled a database of 1699 Pleistocene Palearctic sites based on fossil bird sites. We also compiled a taphonomical database from the Middle Palaeolithic assemblages of Gibraltar. We establish a clear, previously unknown and widespread, association between Neanderthals, raptors and corvids. We show that the association involved the direct intervention of Neanderthals on the bones of these birds, which we interpret as evidence of extraction of large flight feathers. The large number of bones, the variety of species processed and the different temporal periods when the behaviour is observed, indicate that this was a systematic, geographically and temporally broad, activity that the Neanderthals undertook. Our results, providing clear evidence that Neanderthal cognitive capacities were comparable to those of

estratégicos

Directory of Open Access Journals (Sweden)

Jesús Gabriel Moreno Navarro

2006-01-01

Full Text Available El trabajo que se presenta está extraído de una tesis doctoral defendida en abril de 2003 por el mismo autor. En ella se ha elaborado una capa vectorial sobre la base de la Digital Chart of the World a la que se han añadido las principales líneas marítimas. Al tratarse de una red intercontinental con cerca de 100.000 arcos, la escala presentó problemas de proyección y una gran carga de trabajo para conseguir la actualización de los atributos, así como la garantía de su conectividad. En estos atributos se reflejó el tiempo de estiba en los puertos, la diferente impedancia en los medios (barco-camión-ferrocarril y la rectificación de las distancias cuya traducción en valores métricos quedaba distorsionada al progresar en latitud. El modelo ha permitido explicar las razones del alejamiento de los flujos entre Marruecos y la Unión Europea a través de puertos alternativos a los del Estrecho de Gibraltar. Mediante el módulo Network de Esri ha podido ponerse de manifiesto la dudosa competitividad de un enlace fijo en el Estrecho de Gibraltar, las ventajas comparativas del Arco Mediterráneo, la identificación de centros estratégicos en la red, etc. De este modo se han aportado nuevas bases para considerar el papel de los corredores de transporte en los planes de infraestructuras. Este modelo fue empleado también en dos estudios de competitividad para dos nuevos puertos en proyecto: Plan de Ordenación Territorial para el nuevo puerto Tánger-Med y Estudio de Sostenibilidad Socioeconómica del Puerto de Granadilla de Abona (Tenerife.

Dispersal of the monarch butterfly (Danaus plexippus over southern Spain from its breeding grounds

Directory of Open Access Journals (Sweden)

Obregón, R.

2018-01-01

Full Text Available From 2000–2016, monarch butterflies were detected at 127 locations away from their usual coastal breeding areas in the south of the Iberian peninsula. These findings were recorded in the summer–autumn period, coinciding with the highest abundance of individuals and the highest proportion of patches occupied in their reproduction areas near the Strait of Gibraltar. These dispersing individuals have no chance of successfully establishing new colonies at these sites because the food plants for egg laying do not grow in the localities where they were detected. However, these dispersive movements could be the source of their successful colonisation on food plants growing in other areas of the Iberian peninsula and in other Mediterranean countries.

Recent sea surface temperature trends and future scenarios for the Mediterranean Sea:

Directory of Open Access Journals (Sweden)

Mohamed Shaltout

2014-06-01

Full Text Available We analyse recent Mediterranean Sea surface temperatures (SSTs and their response to global change using 1/4-degree gridded advanced very-high-resolution radiometer (AVHRR daily SST data, 1982-2012. These data indicate significant annual warming (from 0.24°C decade-1 west of the Strait of Gibraltar to 0.51°C decade-1 over the Black Sea and significant spatial variation in annual average SST (from 15ºC over the Black Sea to 21°C over the Levantine sub-basin. Ensemble mean scenarios indicate that the study area SST may experience significant warming, peaking at 2.6°C century-1 in the Representative Concentration Pathways 85 (RCP85 scenario.

Along-strike variations of the External Betics basal detachment: Implications on the evolution of a curved FTB

Science.gov (United States)

Jiménez-Bonilla, Alejandro; Torvela, Taija; Balanyá, Juan Carlos; Expósito, Inmaculada; Díaz-Azpiroz, Manuel

2017-04-01

Analogue models have successfully tested the role of different parameters on the orogenic curvature. Among them: (1) along-strike variations of the frictional properties of the detachment layer, (2) the topography of the basement, (3) the syn-tectonic sedimentation and/or erosion and (4) the indenter shape. Previous works have pointed out that, across-strike the central Betic fold-and-thrust belt (FTB), northern branch of the Gibraltar Arc, a change on the structural style and on the topographic envelope (α) coincide with the pinch-out of Triassic evaporites and with a change in the basement dip (β) that induced changes on the wedge geometry and the basal friction (Jiménez-Bonilla et al., 2016). In this work, we tried to constrain the external orogenic wedge geometry to study the evolution of the western Betics FTB and, comparing it with the central Betics FTB, to delve into the structural variations along-strike the Betic chain. In the present work, field data together with reflection seismic interpretations permit us to constrain the across-strike variations on the structural style of the western Betics FTB. The internal FTB is deformed by SW-NE, kilometric-scale, and non-cylindrical folds detached within Triassic evaporites. The middle FTB is characterized by the profusion of allochtonous Triassic mudstones and evaporites and it is deformed into a dextral transpressive band. In the frontal FTB, a Middle Miocene package, the Olistostromic Unit, is deformed by foreland-verging thrusts overlying paleomargin-derived units. Accordingly, these differences on the structural style across the western Betics FTB could be attributable to the variations on the frictional properties of the detachment level. Regarding the wedge geometry, the topographic relief envelope (α) of the western Betics FTB is similar to that one of the central Betics. However, β is significantly lower than in the central Betics (ca. 2° vs >4°). Moreover, neither Triassic pinch-out nor basement

El proceso del cambio tecnológico en zonas de borde. El caso andaluz (España

Directory of Open Access Journals (Sweden)

Rosa Jordá Borrell

1997-07-01

Full Text Available The central theme of this article is a look at the process of technological change in a peripheral border zone (Andalusia in the south of the European Union and Spain, and which, as well, borders Morocco across the Strait of Gibraltar. This process of change, in our opinion, is due in part to the area's having only one market, and to the fact that between 1990 and 1998 the regional institutions have given place to a modernization technology. Other causes are the structure of the organizational scherne of the environment, the appearance of some innovative clusters related to the industry that tends to externalize the process of production (aeronautics, automobile and the emergence of innovative, creative, research and development companies (I+D.

Stop to go forward; Parar para avanzar

Energy Technology Data Exchange (ETDEWEB)

Dendrael, I.

2016-07-01

Combined-cycle plants are arguably the least well-known electrical plants, but in Spain they account for 25% of the country’s installed capacity. There are ten units based on this technology, manufactured by Siemens: two in Campo de Gibraltar (Cádiz), three in Palos de la Frontera (Huelva), two in Arrúbal (La Rioja) and three more in Sagunto (Valencia). Today, these plants continue to work as the most useful safeguard to guarantee Europe’s energy generation system, counted among the least contaminant fossil fuel combustion plants in the world. Their thermodynamic efficiency, in other words, the percentage of energy that can be obtained from the fuel, is around 60% (much higher than that generated by a coal-fired plant). (Author)

Recent sea surface temperature trends and future scenarios for the Mediterranean Sea

Directory of Open Access Journals (Sweden)

Mohamed Shaltout

2014-06-01

Full Text Available We analyse recent Mediterranean Sea surface temperatures (SSTs and their response to global change using 1/4-degree gridded advanced very-high-resolution radiometer (AVHRR daily SST data, 1982–2012. These data indicate significant annual warming (from 0.24 °C decade−1 west of the Strait of Gibraltar to 0.51 °C decade−1 over the Black Sea and significant spatial variation in annual average SST (from 15 °C over the Black Sea to 21 °C over the Levantine sub-basin. Ensemble mean scenarios indicate that the study area SST may experience significant warming, peaking at 2.6 °C century−1 in the Representative Concentration Pathways 85 (RCP85 scenario.

Plutonium and polonium concentrations in the different water masses crossing the Strait of Gibraltar

International Nuclear Information System (INIS)

Gasco, C.; Anton, M.P.

1999-01-01

In this paper total Pu and Po concentrations in the water column are presented as part of a study to determine the exchange fluxes and overall budget of these selected nuclides within the Atlantic and Mediterranean basins. Polonium is a natural radionuclide continuously input to the sea via atmospheric deposition from the radon existing in the air. Plutonium is a man-made radionuclide that was mostly introduced in the atmosphere during the 60's nuclear testing. Since then, it has been gradually disappearing due to fallout and the banning of nuclear atmospheric explosions

Joint sea studies of the IAEA and European Union mediterranean partner ship

International Nuclear Information System (INIS)

Fowler, S.; Miquel, J.C.; Boisson, F.

1998-01-01

Several oceanographic and geographic features of the Mediterranean Sea render it particularly vulnerable to the potential effects of anthropogenic pollutants. The sea is a relatively shallow, semi-enclosed body of water with only limited water exchange taking place at Straits of Gibraltar and through the Bosphorus. Less saline Atlantic surface water enters at Gibraltar and slowly circulates counter clockwise around the Mediterranean basin. There it gradually becomes warmer and more saline due to insolation and intense evaporation. The weak coastal current systems and general lack of tides combine to reduce dispersion of pollutants entering its coastal water. Furthermore, recent construction of dams on some major rivers have substantially reduced spring runoff which tends to cleanse the shelf region of deposited contaminants. Given the Sea's special geographical setting and potential sensitivity to human activity, it is not surprising that over the last decade much effort has been put into studying its biogeochemical structure and functioning. Furthermore, the Sea's restricted size affords marine scientists the opportunity to study, on a reduced scale, processes typical of the world's oceans. Recent trends in oceanography have shown that the degree of our understanding these processes significantly improves when the questions to be answered are addressed in a multidisciplinary way. Recognizing this fact, the European Union (EU) has mounted various large-scale multidisciplinary marine programmes, several of which have focused on the Mediterranean Sea. Because of its long history of collaborative work in the Mediterranean, the IAEA's Marine Environmental Laboratory (MEL) in Monaco has been invited by several EU partner institutes to contribute to these programmes, usually in the area of employing nuclear techniques to study key oceanic processes. These EU-supported programmed have been instrumental in broadening MEL's extrabugetary funding base, which is often

Crustal and upper mantle shear velocities of Iberia, the Alboran Sea, and North Africa from ambient noise and ballistic finite-frequency Rayleigh wave tomography

Science.gov (United States)

Palomeras, I.; Villasenor, A.; Thurner, S.; Levander, A.; Gallart, J.; mimoun, H.

2013-12-01

The complex Mesozoic-Cenozoic Alpine deformation in the western Mediterranean extends from the Pyrenees in northern Spain to the Atlas Mountains in southern Morocco. The Iberian plate was accreted to the European plate in late Cretaceous, resulting in the formation of the Pyrenees. Cenozoic African-European convergence resulted in subduction of the Tethys oceanic plate beneath Europe. Rapid Oligocene slab rollback from eastern Iberia spread eastward and southward, with the trench breaking into three segments by the time it reached the African coast. One trench segment moved southwestward and westward creating the Alboran Sea, floored by highly extended continental crust, and building the encircling Betics Rif mountains comprising the Gibraltar arc, and the Atlas mountains, which formed as the inversion of a Jurassic rift. A number of recent experiments have instrumented this region with broad-band arrays (the US PICASSO array, Spanish IberArray and Siberia arrays, the University of Munster array), which, including the Spanish, Portuguese, and Moroccan permanent networks, provide a combined array of 350 stations having an average interstation spacing of ~60 km. Taking advantage of this dense deployment, we have calculated the Rayleigh waves phase velocities from ambient noise for short periods (4 s to 40 s) and teleseismic events for longer periods (20 s to 167 s). Approximately 50,000 stations pairs were used to measure the phase velocity from ambient noise and more than 160 teleseismic events to measure phase velocity for longer periods. The inversion of the phase velocity dispersion curves provides a 3D shear velocity for the crust and uppermost mantle. Our results show differences between the various tectonic regions that extend to upper mantle depths (~200 km). In Iberia we obtain, on average, higher upper mantle shear velocities in the western Variscan region than in the younger eastern part. We map high upper mantle velocities (>4.6 km/s) beneath the

Unraveling the tectonic history of northwest Africa: Insights from shear-wave splitting, receiver functions, and geodynamic modeling

Science.gov (United States)

Miller, M. S.; Becker, T. W.; Allam, A. A.; Alpert, L. A.; Di Leo, J. F.; Wookey, J. M.

2013-12-01

The complex tectonic history and orogenesis in the westernmost Mediterranean are primarily due to Cenozoic convergence of Africa with Eurasia. The Gibraltar system, which includes the Rif Mountains of Morocco and the Betics in Spain, forms a tight arc around the Alboran Basin. Further to the south the Atlas Mountains of Morocco, an example of an intracontinental fold and thrust belt, display only modest tectonic shortening, yet have unusually high topography. To the south of the Atlas, the anti-Atlas is the oldest mountain range in the region, has the lowest relief, and extends toward the northern extent of the West African Craton. To help unravel the regional tectonics, we use new broadband seismic data from 105 stations across the Gibraltar arc into southern Morocco. We use shear wave splitting analysis for a deep (617 km) local S event and over 230 SKS events to infer azimuthal seismic anisotropy and we image the lithospheric structure with receiver functions. One of the most striking discoveries from these methods is evidence for localized, near vertical-offset deformation of both crust-mantle and lithosphere-asthenosphere interfaces at the flanks of the High Atlas. These offsets coincide with the locations of Jurassic-aged normal faults that were reactivated during the Cenozoic. This suggests that these lithospheric-scale discontinuities were involved in the formation of the Atlas and are still active. Shear wave splitting results show that the inferred stretching axes are aligned with the highest topography in the Atlas, suggesting asthenospheric shearing in mantle flow guided by lithospheric topography. Geodynamic modeling shows that the inferred seismic anisotropy may be produced by the interaction of mantle flow with the subducted slab beneath the Alboran, the West African Craton, and the thinned lithosphere beneath the Atlas. Isostatic modeling based on these lithospheric structure estimates indicates that lithospheric thinning alone does not explain the

Avances al estudio de impacto ambiental del proyecto de aprovechamiento integral de recursos naturales "Mar de Trafalgar"

Directory of Open Access Journals (Sweden)

Bejarano, A.

2006-12-01

Full Text Available The project "Sea of Trafalgar" was conceived with the objective to take advantage of the natural resources the gulf of Cadiz, of a clean, sustainable form and with little or null environmental repercussion, settling down as it bases of the mentioned development the advantage of the enormous aeolian potential that displays the areas that they surround to the Straight of Gibraltar bounded to offshore electrical wind generation were considered in parallel way, other vectors of development, being the impulse of a modern aquaculture in open sea and the regeneration of the traditional places for casting fishing-nets were the best alternatives selected to profit the excellent bioclimatic conditions of the gulf of Cadiz. The group of all this considerations in a single performance does that the project "Sea of Trafalgar" appears to the vanguard of the present technological development, not telling on any type of referring to European nor world-wide level.El proyecto "Mar de Trafalgar" fue concebido con el objetivo de aprovechar íntegramente los recursos naturales del golfo de Cádiz, de una forma limpia, sostenible y con escasa o nula repercusión ambiental, estableciéndose como base del citado desarrollo el aprovechamiento del enorme potencial eólico que presentan las áreas que circundan al Estrecho de Gibraltar. Íntimamente ligado a la aerogeneración eléctrica offshore se plantearon, de forma paralela, otros vectores de desarrollo, siendo el impulso de una moderna acuicultura en mar abierto y la regeneración de los caladeros artesanales de pesca las alternativas seleccionadas para la internalización de las excelentes condiciones bioclimáticas del golfo gaditano. El agrupamiento de toda esta batería de consideraciones en una sola actuación hace que el proyecto "Mar de Trafalgar" se presente a la vanguardia del desarrollo tecnológico actual, no contando con ningún tipo de referentes a nivel europeo ni mundial.

Variations in Mediterranean-Atlantic exchange across the late Pliocene climate transition

Science.gov (United States)

García-Gallardo, Ángela; Grunert, Patrick; Piller, Werner E.

2018-03-01

Mediterranean-Atlantic exchange through the Strait of Gibraltar plays a significant role in the global ocean-climate dynamics in two ways. On one side, the injection of the saline and warm Mediterranean Outflow Water (MOW) contributes to North Atlantic deep-water formation. In return, the Atlantic inflow is considered a sink of less saline water for the North Atlantic Ocean. However, while the history of MOW is the focus of numerous studies, the Pliocene Atlantic inflow has received little attention so far. The present study provides an assessment of the Mediterranean-Atlantic exchange with a focus on the Atlantic inflow strength and its response to regional and global climate from 3.33 to 2.60 Ma. This time interval comprises the mid-Pliocene warm period (MPWP; 3.29-2.97 Ma) and the onset of the Northern Hemisphere glaciation (NHG). For this purpose, gradients in surface δ18O records of the planktonic foraminifer Globigerinoides ruber between the Integrated Ocean Drilling Program (IODP) Hole U1389E (Gulf of Cádiz) and Ocean Drilling Program (ODP) Hole 978A (Alboran Sea) have been evaluated. Interglacial stages and warm glacials of the MPWP revealed steep and reversed (relative to the present) W-E δ18O gradients suggesting a weakening of Mediterranean-Atlantic exchange likely caused by high levels of relative humidity in the Mediterranean region. In contrast, periods of stronger inflow are indicated by flat δ18O gradients due to more intense arid conditions during the severe glacial Marine Isotope Stage (MIS) M2 and the initiation of NHG (MIS G22, G14, G6-104). Intensified Mediterranean-Atlantic exchange in cold periods is linked to the occurrence of ice-rafted debris (IRD) at low latitudes and a weakening of the Atlantic Meridional Overturning Circulation (AMOC). Our results thus suggest the development of a negative feedback between AMOC and exchange rates at the Strait of Gibraltar in the latest Pliocene as it has been proposed for the late Quaternary.

Iberian plate kinematics: A jumping plate boundary between Eurasia and Africa

Science.gov (United States)

Srivastava, S.P.; Schouten, Hans; Roest, W.R.; Klitgord, Kim D.; Kovacs, L.C.; Verhoef, J.; Macnab, R.

1990-01-01

THE rotation of Iberia and its relation to the formation of the Pyrenees has been difficult to decipher because of the lack of detailed sea-floor spreading data, although several models have been proposed1-7. Here we use detailed aeromagnetic measurements from the sea floor offshore of the Grand Banks of Newfoundland to show that Iberia moved as part of the African plate from late Cretaceous to mid-Eocene time, with a plate boundary extending westward from the Bay of Biscay. When motion along this boundary ceased, a boundary linking extension in the King's Trough to compression along the Pyrenees came into existence. Finally, since the late Oligocene, Iberia has been part of the Eurasian plate, with the boundary between Eurasia and Africa situated along the Azores-Gibraltar fracture zone.

Salvadorianae. III. Una descripció prelinneana de Silene niceensis All., deguda a Jaume Salvador i Pedrol, a l'edició de 1686 del Botanicum Monspeliense de Pèire Magnol

Directory of Open Access Journals (Sweden)

Camarasa, Josep M.

2000-12-01

Full Text Available Silene niceensis All. (Cariophillaceae is a plant found on litoral sands of Western Mediterranian and also of Iberian Atlantic shores from Gibraltar to the Rias Baixas and in some places in Greece. It had been described twice in prelinnean times but Linné has neglected it in his works. First prelinnean description, though published by Pierre Magnol in the Appedix to the second edition (1686 of Botanicum monspeliense,has been wrote on the basis of materials and a short description sent to Magnol by Jaume Salvador i Pedrol. One specimen of this plant in Salvador Herbarium hold a short description that could be the original one by Jaume Salvador. The second one was published on a different name by Tournefort in Institutiones Rei herbariae. It is also one specimen of S. niceensisAll. in Salvador Herbarium under this identity. Pourret, studying this herbarium to put on etiquets the linnean name of each specimen (1792-98, realize the specific identity of both S. niceensis All. specimens but ignoring the description published by Allioni in 1773 he give them the new name of S. arenaria Pourr. Also Desfontaines described under the name of S. arenaria Desf. in his Flora Atlantica (1798-99 the same species on the basis of specimens collected near the Gibraltar Strait. Both. Pourrett and Desfontaines names, or today invalid and under sinonimy.

La cariofil làcia Silene niceensis All. pròpia dels sorrats litorals de la Mediterrània occidental i present també a les costes atlàntiques ibèriques. des de l' estret de Gibraltar fins a les Rias Baixas i en alguna localitat grega, havia estar descrita al menys dues vegades temps prelinneans malgrat que Linné mateix la ignorés a les seves obres. La primera descripció prelinneana. bé que publicada por Péire Magnol a l’apèndix a la segona edició del seu Botanicum monspeliense,. es feu sobre la base de materials i fins i tot d

Gibraltar Experiment: A Plan for Dynamic and Kinematic Investigations of Strait Mixing, Exchange and Turbulence.

Science.gov (United States)

1986-08-01

Iuz y clorofila; conl posible opcibn a determinar metales pesados en sedimentos, en el Estrecho de Gibral- tar y zonas adyacentes. Todo ello muy...Estrecho. El trabajo de campo acabara& en Abril y se podra’ disponer de un informe pr-eli- minar par-a despue’s del Verano. Este programa ha sido...pademas realizar una primera campar~a en Junio de 1985 la usari’amas coma campa de pruebas . Aparte de esta campah’a pensamos realizar otra en Octubre a

Gibraltar Experiment: A Plan for Dynamic and Kinematic Investigations of Strait Mixing, Exchange and Turbulence

Science.gov (United States)

1985-08-01

otros proyectos en curso. Plan de trabajo. - En conjuncio’n con las campahias de Ffisica, se pretende ha- cer un muestr-eo de los paraimetros...prioritario establecer nuevo instrumental en dos puntos de la costa, en ambas partes del Estrecho, Ceuta en una, y Tarifa o Algeciras en otra, para obtener

La olla a presión: cómo la seguridad fronteriza sigue aumentando el caos

Directory of Open Access Journals (Sweden)

Andersson, Ruben

2015-12-01

Full Text Available This paper explores the problems and contradictions of the so-called «balloon effect» in migratory processes, and the need to elaborate a global and interconnected understanding of population flows across borders as the necessary basis to design just and effective migratory policies.The revision of the successive «crisis» in the Mediterranean borders, starting with the first small boats (pateras which used to cross the Strait of Gibraltar all the way to today’s «Refugee Crisis», makes sufficiently clear that the pressure on certain potential migratory entry routes does not discourage the will to cross, but rather forces immigrants and refugees in other directions. Ethnographic data show how, for example, the today prestigious Spanish border control model in Gibraltar did not stop the problem but rather provoked the shiftof migratory flows to more dangerous routes in the Sahara and the North of Africa. Spain’s problem eventually became Italy’s problem and, in turn, as routes moved East, Greece’s problem: a vicious cycle manifesting the failure of European policies. The author follows the life histories of migrants he worked in the route from Senegal to Morocco who, in their respective African transits, have had to face walls, borders, new surveillance technologies and cross-border mafias. Migrants’ experiences signal a progressive process: the globalization and commodification of irregular routes, emerging in parallel to migratory inhibition mechanismsEste artículo plantea los problemas y contradicciones del llamado «efecto globo» en los procesos migratorios y la necesidad de partir de una visión global e interconectadas de los flujos poblacionales a través de las fronteras para la elaboración de políticas migratorias justas y efectivas. La revisión de las «crisis» en las fronteras del Mediterráneo, desde las primeras «pateras» que cruzaban Gibraltar hasta la presente «crisis de refugiados», evidencia el hecho de

Interaction of tectonic and depositional processes that control the evolution of the Iberian Gulf of Cadiz margin

Science.gov (United States)

Maldonado, A.; Nelson, C.H.

1999-01-01

This study provides an integrated view of the growth patterns and factors that controlled the evolution of the Gulf of Cadiz continental margin based on studies of the tectonic, sedimentologic and oceanographic history of the area. Seven sedimentary regimes are identified, but there are more extensive descriptions of the late Cenozoic regimes because of the larger data base. The regimes of the Mesozoic passive margin include carbonate platforms, which become mixed calcareous-terrigenous deposits during the Late Cretaceous-early Tertiary. The Oligocene and Early Miocene terrigenous regimes developed, in contrast, over the active and transcurrent margins near the African-Iberian plate boundary. The top of the Gulf of Cadiz olistostrome, emplaced in the Late Miocene, is used as a key horizon to define the 'post-orogenic' depositional regimes. The Late Miocene progradational margin regime is characterized by a large terrigenous sediment supply to the margin and coincides with the closing of the Miocene Atlantic-Mediterranean gateways. The terrigenous drift depositional regime of the Early Pliocene resulted from the occurrence of high eustatic sea level and the characteristics of the Mediterranean outflow currents that developed after the opening of the Strait of Gibraltar. The Late Pliocene and Quaternary regimes are dominated by sequences of deposits related to cycles of high and low sea levels. Deposition of shelf-margin deltas and slope wedges correlate with regressive and low sea level regimes caused by eustasy and subsidence. During the highstand regimes of the Holocene, inner shelf prograding deltas and deep-water sediment drifts were developed under the influence of the Atlantic inflow and Mediterranean outflow currents, respectively. A modern human cultural regime began 2000 years ago with the Roman occupation of Iberia; human cultural effects on sedimentary regimes may have equalled natural factors such as climate change. Interplay of tectonic and

La invasión musulmana de la Península Ibérica en el año 711 y la flota de Ifriqiya

Directory of Open Access Journals (Sweden)

Montenegro, Julia

2012-12-01

Full Text Available The invasion of the Visigothic Kingdom of Toledo came about through the expansion of the Muslim Empire, but the real possibility and ease with which it occurred was brought about by the pact made with Count Julian and the help of the Witizan faction. Everything seems to indicate that the Muslim fl eet of Ifriqiya did not participate initially, despite the interpretation made by some, of several references from certain Muslim authors. We believe that the ships in which Ayyash (Abbas Ibn Sharahil (Ujayl, Akhyal sailed from Al-Andalus to Ifriqiya were those that Musa Ibn Nusayr had built in vast numbers on the shores of Africa, after Tariq Ibn Ziyad set sail for the Iberian Peninsula, and which were used to send him reinforcements, so that Musa himself could cross the Straits of Gibraltar in the year 93 of the Hegira, and also to transport the spoils of war that Musa took to Tangier in the year 95 of the Hegira.

La invasión del reino visigodo de Toledo fue resultado del propio expansionismo musulmán, pero la posibilidad real y la facilidad con la que se llevó a cabo fue consecuencia del pacto con don Julián y de la ayuda de la facción witizana. Pero, desde luego todo indica que no participó en un principio la flota musulmana de Ifriqiya, pese a la interpretación que algunos hacen de varias referencias de ciertos autores musulmanes. Consideramos que los barcos en los que Ayyash (Abbas Ibn Sharahil (Uyayl, Ajyal se trasladó desde Al-Andalus hasta Ifriqiya eran los que Muza Ibn Nusayr había mandado construir en gran número en la orilla africana después de la partida de Tariq Ibn Ziyad a la península Ibérica, los cuales fueron utilizados para enviar refuerzos a éste, así como para que el mismo Muza pudiera atravesar el estrecho de Gibraltar en el año 93 de la Hégira y también para transportar hasta Tánger el botín de guerra que Muza se llevó en el año 95 de la Hégira.

Future projections of the surface heat and water budgets of the Mediterranean Sea in an ensemble of coupled atmosphere-ocean regional climate models

Energy Technology Data Exchange (ETDEWEB)

Dubois, C.; Somot, S.; Deque, M.; Sevault, F. [CNRM-GAME, Meteo-France, CNRS, Toulouse (France); Calmanti, S.; Carillo, A.; Dell' Aquilla, A.; Sannino, G. [ENEA, Rome (Italy); Elizalde, A.; Jacob, D. [Max Planck Institute for Meteorology, Hamburg (Germany); Gualdi, S.; Oddo, P.; Scoccimarro, E. [INGV, Bologna (Italy); L' Heveder, B.; Li, L. [Laboratoire de Meteorologie Dynamique, Paris (France)

2012-10-15

Within the CIRCE project ''Climate change and Impact Research: the Mediterranean Environment'', an ensemble of high resolution coupled atmosphere-ocean regional climate models (AORCMs) are used to simulate the Mediterranean climate for the period 1950-2050. For the first time, realistic net surface air-sea fluxes are obtained. The sea surface temperature (SST) variability is consistent with the atmospheric forcing above it and oceanic constraints. The surface fluxes respond to external forcing under a warming climate and show an equivalent trend in all models. This study focuses on the present day and on the evolution of the heat and water budget over the Mediterranean Sea under the SRES-A1B scenario. On the contrary to previous studies, the net total heat budget is negative over the present period in all AORCMs and satisfies the heat closure budget controlled by a net positive heat gain at the strait of Gibraltar in the present climate. Under climate change scenario, some models predict a warming of the Mediterranean Sea from the ocean surface (positive net heat flux) in addition to the positive flux at the strait of Gibraltar for the 2021-2050 period. The shortwave and latent flux are increasing and the longwave and sensible fluxes are decreasing compared to the 1961-1990 period due to a reduction of the cloud cover and an increase in greenhouse gases (GHGs) and SSTs over the 2021-2050 period. The AORCMs provide a good estimates of the water budget with a drying of the region during the twenty-first century. For the ensemble mean, he decrease in precipitation and runoff is about 10 and 15% respectively and the increase in evaporation is much weaker, about 2% compared to the 1961-1990 period which confirm results obtained in recent studies. Despite a clear consistency in the trends and results between the models, this study also underlines important differences in the model set-ups, methodology and choices of some physical parameters inducing

Late Pliocene History of Mediterranean Outflow Water in the Gulf of Cadiz (IODP Expedition 339, Site U1389)

Science.gov (United States)

Grunert, P.; Balestra, B.; Flores, J. A.; Sierro, F. J.; García Gallardo, Á.; Piller, W. E.; Aubry, M. P.

2014-12-01

The opening and closure of ocean gateways play an important role amongst climate forcing mechanisms: surface and deep-water circulation are altered, and hence global heat transport. An important component of North Atlantic circulation patterns is the warm and saline Mediterranean Outflow Water (MOW) that enters the North Atlantic via the Gibraltar Strait. Its onset and early history after the opening of the Gibraltar Strait at 5.3 Ma are poorly constrained and its impact on oceanography and climate in the Pliocene are largely unexplored. Current research efforts in the scope of projects funded by the Austrian Science Fund (FWF-P25831-N29) and the Max Kade Foundation aim to improve our knowledge about this early phase of MOW. Research focuses on Sites U1387C (upper Miocene-lower Pliocene; ~5.8-3.8 Myrs) and U1389E (middle-upper Pliocene; ~3.7-2.8) drilled during IODP Expedition 339 in the northern Gulf of Cádiz close to the source area of MOW. At IODP Site U1389E, a 280m-thick sequence of upper Pliocene contourites is studied to reconstruct MOW behavior and potential paleoceanographic and paleoclimatic feedback mechanisms during the Mid-Pliocene Thermal Optimum. Currently, a reliable age model is developed for the studied interval based on bio-, chemo-, and cyclostratigraphy. Several biostratigraphic datums have been identified from analyses of calcareous nannoplankton and planktic foraminifera which indicate a depositional age between 3.65 Ma and 2.87 Ma. In some intervals of the record a further refinement of the age model at the millenial scale is complicated by poor recovery. However, preliminary results from high-resolution geochemical analyses of the bulk sediment (TOC, CaCO3 and S) and shells of the planktic foraminifer Globigerinoides ruber (δ18O, δ13C) reveal distinct cyclic patterns in several well recovered intervals. Based on an average sedimentation rate of ~25cm/ka, these cycles most likely reflect precessional forcing. Current paleoceanographic

The effects of a wind farm on birds in a migration point: the Strait of Gibraltar.

OpenAIRE

Lucas, Manuela de; Janss, Guyonne, F.E.; Ferrer, Miguel

2004-01-01

The interaction between birds and wind turbines is an important factor to consider when a wind farm is constructed. A wind farm and two control areas were studied in Tarifa (Andalusia Province, southern Spain, 30STF590000–30STE610950).Variables were studied along linear transects in each area and observations of flight were also recorded from fixed points in the wind farm. The main purpose of our research was to determine the impact and the degree of flight behavioural change in birds flights...

Ontogeny of the maxilla in Neanderthals and their ancestors.

Science.gov (United States)

Lacruz, Rodrigo S; Bromage, Timothy G; O'Higgins, Paul; Arsuaga, Juan-Luis; Stringer, Chris; Godinho, Ricardo Miguel; Warshaw, Johanna; Martínez, Ignacio; Gracia-Tellez, Ana; de Castro, José María Bermúdez; Carbonell, Eudald

2015-12-07

Neanderthals had large and projecting (prognathic) faces similar to those of their putative ancestors from Sima de los Huesos (SH) and different from the retracted modern human face. When such differences arose during development and the morphogenetic modifications involved are unknown. We show that maxillary growth remodelling (bone formation and resorption) of the Devil's Tower (Gibraltar 2) and La Quina 18 Neanderthals and four SH hominins, all sub-adults, show extensive bone deposition, whereas in modern humans extensive osteoclastic bone resorption is found in the same regions. This morphogenetic difference is evident by ∼5 years of age. Modern human faces are distinct from those of the Neanderthal and SH fossils in part because their postnatal growth processes differ markedly. The growth remodelling identified in these fossil hominins is shared with Australopithecus and early Homo but not with modern humans suggesting that the modern human face is developmentally derived.

Tsunamigenic earthquakes in the Gulf of Cadiz: fault model and recurrence

Directory of Open Access Journals (Sweden)

L. M. Matias

2013-01-01

Full Text Available The Gulf of Cadiz, as part of the Azores-Gibraltar plate boundary, is recognized as a potential source of big earthquakes and tsunamis that may affect the bordering countries, as occurred on 1 November 1755. Preparing for the future, Portugal is establishing a national tsunami warning system in which the threat caused by any large-magnitude earthquake in the area is estimated from a comprehensive database of scenarios. In this paper we summarize the knowledge about the active tectonics in the Gulf of Cadiz and integrate the available seismological information in order to propose the generation model of destructive tsunamis to be applied in tsunami warnings. The fault model derived is then used to estimate the recurrence of large earthquakes using the fault slip rates obtained by Cunha et al. (2012 from thin-sheet neotectonic modelling. Finally we evaluate the consistency of seismicity rates derived from historical and instrumental catalogues with the convergence rates between Eurasia and Nubia given by plate kinematic models.

Slab tears and intermediate-depth seismicity

Science.gov (United States)

Meighan, Hallie E.; ten Brink, Uri S.; Pulliam, Jay

2013-01-01

Active tectonic regions where plate boundaries transition from subduction to strike slip can take several forms, such as triple junctions, acute, and obtuse corners. Well-documented slab tears that are associated with high rates of intermediate-depth seismicity are considered here: Gibraltar arc, the southern and northern ends of the Lesser Antilles arc, and the northern end of Tonga trench. Seismicity at each of these locations occurs, at times, in the form of swarms or clusters, and various authors have proposed that each marks an active locus of tear propagation. The swarms and clusters start at the top of the slab below the asthenospheric wedge and extend 30–60 km vertically downward within the slab. We propose that these swarms and clusters are generated by fluid-related embrittlement of mantle rocks. Focal mechanisms of these swarms generally fit the shear motion that is thought to be associated with the tearing process.

La acción exterior del Estatuto de Andalucía: Aciertos, desajustes, especificidades ocultas, desarrollos en tiempos de crisis

Directory of Open Access Journals (Sweden)

Alejandro del Valle Gálvez

2013-06-01

Full Text Available The Andalusian Statute of Autonomy of 2007 contains an important content for the autonomic external action. The paper analyzes the structure and originality of the Andalusian international promotion, as well as deficiencies and imbalances in its articles. Especially, the paper discusses how the Statute has preferred to silence foreign specificities of Andalusia, particularly the ones concerning Morocco, Portugal and Gibraltar. These particularities are therefore implicit in articles, but very present in Andalusian outside practice. It also discusses the later developments in the external practice, highlighting important developments (institutional, financial, priorities of the autonomic cooperation to development; This is an area which is now emancipated from the external action, like a set of international actions traditionally coordinated by the Regional minister of the Presidency. The analysis ends with a final valuation of the severe impact of the great recession of 2008 in the Andalusian external action, particularly in the field of development cooperation.

Subcellular evidences of redox imbalance in well-established populations of an endangered limpet. Reasons for alarm?

Science.gov (United States)

Espinosa, Free; Rivera-Ingraham, Georgina A

2016-08-15

Intertidal species are more vulnerable to anthropogenic disturbances than others inhabiting subtidal and offshore habitats. Coastal development frequently results in trace-metal pollution. For endangered species such as Patella ferruginea it can be a high risk that leads local populations to extinction. Three localities were surveyed, one within a natural and unpolluted area and the other two within the harbor of Ceuta (Strait of Gibraltar), on breakwaters outside and inside. The specimens collected inside the harbor reached 3-fold higher Hg content than for those incoming from the natural area. PERMANOVA test indicated that metal composition of the specimens from inside the harbor was different from the rest. In addition, evidence of cell damage was detected in the specimens from the harbor area. This highlights the urgency of undertaking a physiological evaluation of some of the most vulnerable populations, establishing eco-physiological protocols for monitoring and managing populations settled on artificial substrata. Copyright © 2016 Elsevier Ltd. All rights reserved.

El asunto del “Nuestra señora de la Mercedes” (Odyssey

Directory of Open Access Journals (Sweden)

F. Jesús Carrera Hernández

2009-01-01

Full Text Available Este trabajo constituye, básicamente, una valoración del informe emitido en Estados Unidos por el Juez Pizzo en el que ya podemos calificar como asunto del “Nuestra Señora de La Mercedes”, iniciado hace dos años tras las actividades de expolio desarrolladas por la empresa Odyssey en aguas del Atlántico próximas al Estrecho de Gibraltar. Se trata de un caso que afecta directamente a los intereses españoles en relación con el patrimonio cultural submarino situado en zonas próximas a nuestras costas. De convertirse en jurisprudencia, estaremos dando un paso más en aras de la protección del patrimonio cultural, soslayando la aplicación de legislaciones ancladas enla aplicación de principios de salvamento y hallazgos a bienes que poseen un valor arqueológico, histórico o cultural, y que se encuentran en santuarios de nuestros antepasados.

The Pelagos Sanctuary for Mediterranean marine mammals: Marine Protected Area (MPA) or marine polluted area? The case study of the striped dolphin (Stenella coeruleoalba).

Science.gov (United States)

Fossi, Maria Cristina; Panti, Cristina; Marsili, Letizia; Maltese, Silvia; Spinsanti, Giacomo; Casini, Silvia; Caliani, Ilaria; Gaspari, Stefania; Muñoz-Arnanz, Juan; Jimenez, Begoña; Finoia, Maria Grazia

2013-05-15

The concurrence of man-made pressures on cetaceans in the Mediterranean Sea is potentially affecting population stability and marine biodiversity. This needs to be proven for the only pelagic marine protected area in the Mediterranean Sea: the Pelagos Sanctuary for Mediterranean Marine Mammals. Here we applied a multidisciplinary tool, using diagnostic markers elaborated in a statistical model to rank toxicological stress in Mediterranean cetaceans. As a case study we analyzed persistent, bioaccumulative and toxic chemicals combined with a wide range of diagnostic markers of exposure to anthropogenic contaminants and genetic variation as marker of genetic erosion in striped dolphin (Stenella coeruleoalba) skin biopsies. Finally, a statistical model was applied to obtain a complete toxicological profile of the striped dolphin in the Pelagos Sanctuary and other Mediterranean areas (Ionian Sea and Strait of Gibraltar). Here we provide the first complete evidence of the toxicological stress in cetaceans living in Pelagos Sanctuary. Copyright © 2013 Elsevier Ltd. All rights reserved.

«Ter o Archiduque por vezinho» The journey of Charles III to Lisbon in the context of the conflict of the succession of the Spanish monarchy

Directory of Open Access Journals (Sweden)

David Martín Marcos

2012-08-01

Full Text Available The War of the Spanish Succession was the first international conflict in which Portugal took part after the restoration of its independence in 1668. Portuguese integration in the allied group gave Lisbon a central position in the face of the imminent invasion of Spain. The capital city of Portugal was the perfect operations headquarters and the provisional residence of the Archduke Charles during 1704-1705. This article analyzes the Habsburg’s stay in the city and his journeys around the Portuguese geography supervising military preparations in the company of King Peter II. However, the days spent in Lisbon and the trips didn’t actually correspond with a pre-warfare state. Visits to relics and churches, as well as flamboyant festive programs in different cities were carried out in an attempt to proclaim their royal virtues. Only after the conquest of Gibraltar and the Allies entered the Mediterranean Sea did Portugal lose its protagonism.

The Pillar of Heaven. Approximation to the study of the image of the Far West in Greek and Roman sources through the mythical figure of Atlas

Directory of Open Access Journals (Sweden)

Pamina Fernández Camacho

2016-12-01

Full Text Available Atlas is a very complex mythical figure. A rebel Titan in epic tradition, he adopts the roles of both antagonist and helper of Herakles as the hero attempts to fulfill his task of stealing the apples of the Hesperides. Philosophers, geographers and historians consider him an Evemerized astronomer, a king in possession of fabulous riches, or identify him with a mountain. Often juggling positive and negative traits, Atlas’ various incarnations are connected to different themes such as divine genealogies, spatial and cosmogonic landmarks, Eastern influences, abundance in cattle and usurpation myths, which are all part of the image of the regions north and south of the Strait of Gibraltar created and spread by Graeco-Roman civilization. In this article, we propose a study of the literature and iconography related to this mythical character, as a way to give a different perspective to research about the mythical and literary geography of that area.

Rising Temperatures and Dwindling Water Supplies? Perception of Climate Change Among Residents of the Spanish Mediterranean Tourist Coastal Areas

Science.gov (United States)

March, Hug; Saurí, David; Olcina, Jorge

2014-01-01

In this article, we discuss the results of a survey on the perception of climate change in the 14 "tourist zones" (as defined by the Spanish Statistical Institute, INE) that stretch from the French border to Gibraltar alongside the Spanish Mediterranean coast, including the Balearic Islands. Our sample consisted of 1,014 telephone interviews stratified according to the number of tourists staying in each zone. Respondents showed concern for the likely impacts of climate change on jobs and thought that climate change would reduce the economic activity of their areas. Responses were also pessimistic regarding future water availability but agreed with the development of alternative sources such as desalination and water re-use. Household size, educational levels, and employment tended to be the most significant statistical explanatory factors regarding attitudes toward climate change. Respondents in larger households (a variable not tested in the literature as far as we know), respondents with higher education, and respondents working for a wage tended to express more concerns than the rest.

Modeling the dispersal of Levantine Intermediate Water and its role in Mediterranean deep water formation

Science.gov (United States)

Wu, Peili; Haines, Keith

1996-03-01

This paper demonstrates the importance of Levantine Intermediate Water (LIW) in the deep water formation process in the Mediterranean using the modular ocean general circulation model at 0.25° resolution, 19 vertical levels, over the entire Mediterranean with an open Gibraltar strait. LIW formation is strongly prescribed in the Rhodes Gyre region by Haney [1971] relaxation, while in other regions, surface salinity relaxation is much reduced by applying the `mixed' thermohaline surface boundary conditions. Isopycnal diagnostics are used to trace water mass movements, and volume fluxes are monitored at straits. Low viscosity and diffusion are used to permit baroclinic eddies to play a role in water mass dispersal. The overall water budget is measured by an average flux at Gibraltar of 0.8 Sv, of which 0.7 Sv is exchanged with the eastern basin at Sicily. LIW (density around 28.95) spreads rapidly after formation throughout the entire Levantine due to baroclinic eddies. Toward the west, LIW accumulates in the northern and central Ionian, with some entering the Adriatic through Otranto and some mixing southward in eddies and exiting to the western Mediterranean through Sicily. LIW is converted to deep water in the south Adriatic at an average rate of 0.4 Sv. Water exchange through the Otranto strait appears to be buoyancy driven, with a strong bias to the end of winter (March-April), while at Sicily the exchange has a strong symmetric seasonal cycle, with maximum transport of 1.1 Sv in December indicating the effects of wind driving. LIW pathways in the west are complex and variable. In the Tyrrhenian, intermediate water becomes uniform on isopycnal surfaces due to eddy stirring. West of Sardinia, two LIW boundary currents are formed in the Balearic basin; one flows northward up the west coast of Sardinia and Corsica, and one westward along the northern African coast. The northward current is consistent with observations, while the westward current is intermittent for

Mapping the isotopic signature of methane in South-Eastern Spain: complementing biogeochemical long-term research with short term observations

Science.gov (United States)

Àgueda, Alba; Morguí, Josep Anton; Vazquez Garcia, Eusebi; Curcoll, Roger; Lowry, David; Fisher, Rebecca E.; Nisbet, Euan G.

2016-04-01

As a greenhouse gas, methane has a global warming potential of 25 in a 100 year scale. In order to establish mitigation plans it is important to assess its sources and sinks which can be both of geological and biological origin. South-Eastern Spain is a region with many different possible methane sources: i) by seismic activity of many geological faults both inland and in the neighbouring marine region (i.e. the Carboneras fault crossing the Alborán Sea along Málaga coastline); ii) by seepage of methane from hydrates present in the marine regions close to the Gibraltar Strait and the Gulf of Cádiz; iii) by emissions from fossil fuels caused by high traffic of merchant ships and the presence of large harbours (Algeciras, Tetuan and Cádiz), and the Africa - Europe Gas Transport Network in the Gibraltar Strait region; iv) by organic matter decomposition in both highly productive marshlands and eutrophic reservoirs; v) by burning of agricultural debris for energy supply, mainly from olive residues. In this study, a methane mapping survey has been conducted in the area around three atmospheric stations of the ClimaDat Atmospheric Network for Continuous Measurements of Greenhouse Gases (www.climadat.es) located in South-Eastern Spain (Sierra de Grazalema (SGC3), Tarifa (EEC3) and Sierra de Segura (SSC3). A cavity ring down spectrometer (CRDS) (G2301m, Picarro®) installed on a car has been used to measure methane concentrations. Additionally, in selected points, air samples have been collected in Tedlar bags for isotopic signature analysis by CF-GC-IRMS (Continuous Flow Gas Chromatography-Isotope Ratio Mass Spectrometry). In order to obtain a map facilitating the identification of the different methane sources in the background air at regional scale, the mapping of isotopic signature of methane together with its concentration is a useful tool to obtain fast and direct information that will contribute to the knowledge of methane transport at the regional scale and

Estimating the Mediterranean Sea Water Budget: impact of RCM design

Science.gov (United States)

Somot, S.; Elguindi, N.; Sanchez-Gomez, E.; Herrmann, M.; Déqué, M.

2009-09-01

The Mediterranean Sea can be considered as a thermodynamic machine that exchanges water and heat with the Atlantic Ocean through the Strait of Gibraltar and with the atmosphere through its surface. Considering the Mediterranean Sea Water Budget (MSWB) multi-year mean, the Mediterranean basin looses water at the surface due to an excess of evaporation over freshwater input (precipitation, river runoff, Black Sea input). Moreover the MSWB largely drives the Mediterranean Sea water mass formation and therefore a large part of its thermohaline circulation. This could even have an impact on the characteristics of the Atlantic thermohaline circulation through the Mediterranean Outflow Waters that flow into the Atlantic at a depth of about 1000 m. From a climate point of view, the MSWB acts as a water source for the Mediterranean countries and therefore plays an important role on the water resources of the region. The regional physical characteristics of the Mediterranean basin (complex orography, strong land-sea contrast, land-atmosphere coupling, air-sea coupling, river inflow, Gibraltar Strait constraint and complex ocean bathymetry) strongly influence the various components of the MSWB. Moreover extreme precipitation events over land and strong evaporation events over the sea due to local winds can play a non-negligible role on the mean MSWB despite their small spatial and temporal scales. Therefore, modelling the mean behaviour, the interannual variability and the trends of the MSWB is a challenging task of the Regional Climate Model community in the context of climate change. It is actually one of the highlighted issues of the HyMex project planned for the 2010-2020 period. We propose here to start investigating some key scientific issues of the regional modelling of the Mediterranean Sea Water Budget using a wide range of regional climate simulations performed at Météo-France or in the framework of FP6 European projects (ENSEMBLES, CIRCE). The addressed

Seismicity and Seismic Hazard along the Western part of the Eurasia-Nubia plate boundary

Science.gov (United States)

Bezzeghoud, Mourad; Fontiela, João; Ferrão, Celia; Borges, José Fernando; Caldeira, Bento; Dib, Assia; Ousadou, Farida

2016-04-01

The seismic phenomenon is the most damaging natural hazard known in the Mediterranean area. The western part of the Eurasia-Nubia plate boundary extends from the Azores to the Mediterranean region. The oceanic part of the plate boundary is well delimited from the Azores Islands, along the Azores-Gibraltar fault to approximately 12°W (west of the Strait of Gibraltar). From 12°W to 3.5°E, including the Iberia-Nubia region and extending to the western part of Algeria, the boundary is more diffuse and forms a wider area of deformation. The boundary between the Iberia and Nubia plates is the most complex part of the margin. This region corresponds to the transition from an oceanic boundary to a continental boundary, where Iberia and Nubia collide. Although most earthquakes along this plate boundary are shallow and generally have magnitudes less than 5.5, there have been several high-magnitude events. Many devastating earthquakes, some of them tsunami-triggering, inflicted heavy loss and considerable economic damage to the region. From 1920 to present, three earthquakes with magnitudes of about 8.0 (Mw 8.2, 25 November 1941; Ms 8.0, 25 February 1969; and Mw 7.9, 26 May 1975) occurred in the oceanic region, and four earthquakes with magnitudes of about 7.0 (Mw 7.1, 8 May 1939, Santa Maria Island and Mw 7.1, January 1980, Terceira and Graciosa Islands, both in the Azores; Ms 7.1, 20 May 1931, Azores-Gibraltar fracture zone; and Mw 7.3, 10 October 1980, El Asnam, Algeria) occurred along the western part of the Eurasia-Nubia plate boundary. In general, large earthquakes (M ≥7) occur within the oceanic region, with the exception of the El Asnam (Algeria) earthquakes. Some of these events caused extensive damage. The 1755 Lisbon earthquake (˜Mw 9) on the Portugal Atlantic margin, about 200 km W-SW of Cape St. Vincent, was followed by a tsunami and fires that caused the near-total destruction of Lisbon and adjacent areas. Estimates of the death toll in Lisbon alone (~70

Comparison of discrete Fourier transform (DFT) and principal component analysis/DFT as forecasting tools for absorbance time series received by UV-visible probes installed in urban sewer systems.

Science.gov (United States)

Plazas-Nossa, Leonardo; Torres, Andrés

2014-01-01

The objective of this work is to introduce a forecasting method for UV-Vis spectrometry time series that combines principal component analysis (PCA) and discrete Fourier transform (DFT), and to compare the results obtained with those obtained by using DFT. Three time series for three different study sites were used: (i) Salitre wastewater treatment plant (WWTP) in Bogotá; (ii) Gibraltar pumping station in Bogotá; and (iii) San Fernando WWTP in Itagüí (in the south part of Medellín). Each of these time series had an equal number of samples (1051). In general terms, the results obtained are hardly generalizable, as they seem to be highly dependent on specific water system dynamics; however, some trends can be outlined: (i) for UV range, DFT and PCA/DFT forecasting accuracy were almost the same; (ii) for visible range, the PCA/DFT forecasting procedure proposed gives systematically lower forecasting errors and variability than those obtained with the DFT procedure; and (iii) for short forecasting times the PCA/DFT procedure proposed is more suitable than the DFT procedure, according to processing times obtained.

Early Pliocene fishes (Chondrichthyes, Osteichthyes) from Gran Canaria and Fuerteventura (Canary Islands, Spain)

Energy Technology Data Exchange (ETDEWEB)

Betancort, J.F.; Lomoschitz, A.; Meco, J.

2016-07-01

Fossil fish teeth are contained in marine deposits dated at ca 4.8 Ma found on the islands of Gran Canaria and Fuerteventura (Canary Islands, Spain). These islands, situated in the North Atlantic Subtropical Gyre, can be considered a mid-way stopover point between the Caribbean Sea, with the Central American Seaway about to close in this epoch, and the Mediterranean, in the first stage of its post-Messinian Gibraltar Seaway period. Accordingly, there existed extensive pantropical communication, particularly for nektonic animals capable of travelling large distances. In this paper, we present a number of fossil fishes, most of which are identified for the first time on the basis of their teeth: the Chondrichthyes species Carcharocles megalodon, Parotodus benedeni, Cosmopolitodus hastalis, Isurus oxyrinchus, Carcharias cf. acutissima, Carcharhinus cf. leucas, Carcharhinus cf. priscus, Galeocerdo cf. aduncus, and the Osteichthyes species Archosargus cinctus, Labrodon pavimentatum, and Diodon scillae. Coincidences are observed between these ichthyofauna and specimens found in the Azores Islands, the Pacific coast of America and the Mediterranean Sea. (Author)

The Psychological Roots of Creativity in Messages Left by Leonardo da Vinci, Giorgio Vasari, and a Neanderthal Troglodyte

Directory of Open Access Journals (Sweden)

Antonio Cassella

2016-08-01

Full Text Available The perfect memory that informs our local autistic facet is insufficient to deal with the unforeseen change that challenges our nonlocal artistic facet. The loss of quantum nonlocality leads autistics to fail tests rooted in overcoming the less-than-perfect ambiguity that elicits our creativity. The psychological structure by which perfect memory and less-than-perfect creativity empower each other remains in darkness. This article broaches the hypothesis that Leonardo da Vinci envisioned the union of local perfection and nonlocal less-than-perfection, and that he hid his insight in the Adoration of the Magi. Leonardo’s knowledge - expressed here as the logos heuristic—guides a psychological interpretation of the smile of Mona Lisa; of the four avatars of the Vitruvian Man; of the recognition and location of Leonardo’s unknown painting Natività; of the exact location of his lost work, Battaglia di Anghiari; and of a 39,000-year-old abstract engraving in Gorham’s cave at Gibraltar. Logos can be used to single out local, nonlocal computing, and their alliance in pursuing a humanistic path to progress.

Early Pliocene fishes (Chondrichthyes, Osteichthyes from Gran Canaria and Fuerteventura (Canary Islands, Spain

Directory of Open Access Journals (Sweden)

J. F. Betancort

2016-11-01

Full Text Available Fossil fish teeth are contained in marine deposits dated at ca 4.8 Ma found on the islands of Gran Canaria and Fuerteventura (Canary Islands, Spain. These islands, situated in the North Atlantic Subtropical Gyre, can be considered a mid-way stopover point between the Caribbean Sea, with the Central American Seaway about to close in this epoch, and the Mediterranean, in the first stage of its post-Messinian Gibraltar Seaway period. Accordingly, there existed extensive pantropical communication, particularly for nektonic animals capable of travelling large distances. In this paper, we present a number of fossil fishes, most of which are identified for the first time on the basis of their teeth: the Chondrichthyes species Carcharocles megalodon, Parotodus benedeni, Cosmopolitodus hastalis, Isurus oxyrinchus, Carcharias cf. acutissima, Carcharhinus cf. leucas, Carcharhinus cf. priscus, Galeocerdo cf. aduncus, and the Osteichthyes species Archosargus cinctus, Labrodon pavimentatum, and Diodon scillae. Coincidences are observed between these ichthyofauna and specimens found in the Azores Islands, the Pacific coast of America and the Mediterranean Sea.

Modeling Mediterranean Ocean climate of the Last Glacial Maximum

Directory of Open Access Journals (Sweden)

U. Mikolajewicz

2011-03-01

Full Text Available A regional ocean general circulation model of the Mediterranean is used to study the climate of the Last Glacial Maximum. The atmospheric forcing for these simulations has been derived from simulations with an atmospheric general circulation model, which in turn was forced with surface conditions from a coarse resolution earth system model. The model is successful in reproducing the general patterns of reconstructed sea surface temperature anomalies with the strongest cooling in summer in the northwestern Mediterranean and weak cooling in the Levantine, although the model underestimates the extent of the summer cooling in the western Mediterranean. However, there is a strong vertical gradient associated with this pattern of summer cooling, which makes the comparison with reconstructions complicated. The exchange with the Atlantic is decreased to roughly one half of its present value, which can be explained by the shallower Strait of Gibraltar as a consequence of lower global sea level. This reduced exchange causes a strong increase of salinity in the Mediterranean in spite of reduced net evaporation.

Some geophysical constraints to dynamic processes in the Southwestern Mediterranean

Directory of Open Access Journals (Sweden)

P. Chiozzi

1996-06-01

Full Text Available The total tectonic subsidence, thermal state and seismotectonic regime have been analysed to better constrain the dynamic processes which originated the basins of the Southwestern Mediterranean. It is argued that backarc extension and oceanic spreading are the possible and main processes which took place within a compressional framework, driven by the interaction between the African and European plates. As inferred by both subsidence and heat-flux data, in the central part of the Algerian-Balearic basin the crust is oceanic, 20 Ma old on average, originated by a spreading phase, which also affected the Ligurian-Provençal basin. The Alboran basin, which is underlain by stretched continental crust, shows an intermediate seismic activity and a few deep events, explainable by a gravitational collapse of cold lithosphere. After a review of the most recent geodynamical hypotheses, an evolutionary scheme is attempted envisaging the lateral continental escape of the Gibraltar arc. Within a convergent tectonic framework, some lithospheric material could translate almost perpendicular to the convergence direction, and undergo a lateral subduction process, secondary to the main boundary between plates.

Presentación del Libro “Tres Médicos Árabes” Rhases, Averroes, Avicena

Directory of Open Access Journals (Sweden)

Efraim Otero Ruiz

2007-12-01

Pero esa misma migratoriedad, especialmente de las del norte, hizo que gradualmente se extendieran por Siria, Mesopotamia y por todo el antiguo imperio Persa hasta la India, por el oriente; y por Egipto y la costa norte del Africa hasta Gibraltar, por el occidente. Unidos por lenguajes ancestrales derivados del sumerio, el babilonio, el sánscrito y el urdu, que dieron origen al idioma árabe, en esas regiones había enclaves de muchas tribus y muchas religiones, mono y politeístas. El genio de Mahoma y su Corán fue el unificarlos monoteísticamente y darles un sentido de trascendencia, en esta vida y en la otra. Por eso, en el milenio que nos ocupa, se cumplió lo que después describiría maravillosamente Carlyle, el pensador inglés: Aquella estirpe, polvo inflamable por mucho tiempo aislado en el desierto, de golpe prendió fuego y sus llamas formidables se elevaron al cielo desde Dehli, en la India, hasta Granada en España...

Phylogeny, biogeography, and evolution of two Mediterranean snakes, Malpolon monspessulanus and Hemorrhois hippocrepis (Squamata, Colubridae), using mtDNA sequences.

Science.gov (United States)

Carranza, S; Arnold, E N; Pleguezuelos, J M

2006-08-01

Variation in 815bp of mitochondrial DNA from two gene fragments (300bp of cytochrome b and 395-515bp of 12S rRNA) for 26 Malpolon monspessulanus, and cytochrome b for a further 21 individuals, indicates that this species originated in the Maghreb area of Northwest Africa. Here, an estimated 3.5-6Mya, it divided into the western M. m. monspessulanus, and an eastern clade including M. m. insignitus and M. m. fuscus. The very limited genetic differentiation between Maghreb and Southwest European populations of this form suggests that it arrived in the Iberian Peninsula only recently. Population genetics and demographic tests indicate subsequent expansion in this area around 83,000-168,000 year ago. Because present populations of Malpolon arrived recently, mid-Pliocene and at least some Pleistocene fossils of the genus Malpolon in Southwest Europe are probably derived from an earlier invasion from the Maghreb, possibly as early as the end of the Miocene period, 5.3-5.9Mya, when there was a temporary land bridge across the site of the Strait of Gibraltar and the Mediterranean Sea desiccated. The descendants of this earlier invasion must have eventually become extinct, perhaps during one of the Pleistocene glaciations. In contrast to the western M. m. monspessulanus, the greater genetic divergence found in the eastern clade of M. monspessulanus suggests that it dispersed at an earlier date and probably over a longer period, spreading eastwards through northern Libya and Egypt to Syria, Iraq, and Iran, and around the Mediterranean Sea through Turkey into the Aegean archipelagos and the Balkan peninsula. The western and eastern units of M. monspessulanus have different dorsal color pattern, differences in skull structure and exhibit an 8.4% uncorrected genetic divergence in the combined gene fragments investigated here. It is consequently recommended that they should be treated as separate species: M. monspessulanus (sensu stricto) and Malpolon insignitusstat. nov., the

The building of a biodiversity hotspot across a land-bridge in the Mediterranean.

Science.gov (United States)

Molina-Venegas, Rafael; Aparicio, Abelardo; Lavergne, Sébastien; Arroyo, Juan

2015-08-22

Many of the macroevolutionary processes that have shaped present-day phylogenetic patterns were caused by geological events such as plate tectonics and temporary land-bridges. The study of spatial patterns of phylogenetic diversity can provide insights into these past events. Here we focus on a western Mediterranean biodiversity hotspot located in the southern Iberian Peninsula and northwest Africa, two regions that are separated by the Strait of Gibraltar. We explore the spatial structure of the phylogenetic relationships within and across large-scale plant assemblages. Significant turnover in terminal lineages tends to occur between landmasses, whereas turnover in deep lineages tends to occur within landmasses. Plant assemblages in the western ecoregions of this hotspot tend to be phylogenetically overdispersed but are phylogenetically clustered on its eastern margins. We discuss our results in the light of potential scenarios of niche evolution (or conservatism) and lineage diversification. The significant turnover between landmasses suggests a common scenario of allopatric speciation that could have been facilitated by the intermittent joining of the two continents. This may have constituted an important stimulus for diversification and the emergence of this western Mediterranean biodiversity hotspot. © 2015 The Author(s).

Insights on stock structure of round sardinella Sardinella aurita off north-west Africa based on otolith shape analysis.

Science.gov (United States)

Bacha, M; Jeyid, A M; Jaafour, S; Yahyaoui, A; Diop, M; Amara, R

2016-10-01

This study examines the geographic variability in otolith shape of round sardinella Sardinella aurita as a tool for stock discrimination. Fish were analysed from six sampling locations from Senegal to the Mediterranean coast of Morocco. A combination of otolith shape indices and elliptic Fourier descriptors was investigated by multivariate statistical procedures. Within the studied area, three distinct groups were identified with an overall correct classification of 78%. Group A: Nador (Alboran Sea), group B: Casablanca (northern Morocco) and group C: Senegalese-Mauritanian. The results of this study confirm the absence of an Atlantic Ocean-Mediterranean Sea transition for this species, the Gibraltar Strait acting as an efficient barrier for S. aurita population separation. Off north-west Africa, fish from northern Morocco form a single group which is clearly isolated from Senegalese-Mauritanian waters, confirming the existence of a distinct stock in this area. Among group C, some discontinuity exists and suggests the existence of a sedentary fraction of S. aurita in northern Mauritania (Arguin Bank). The results are discussed in relation to oceanographic features and physical barriers to dispersal and fish management strategy in the study area. © 2016 The Fisheries Society of the British Isles.

Recruiting at the Edge: Kinetic Energy Inhibits Anchovy Populations in the Western Mediterranean

Science.gov (United States)

Ruiz, Javier; Macías, Diego; Rincón, Margarita M.; Pascual, Ananda; Catalán, Ignacio A.; Navarro, Gabriel

2013-01-01

The Strait of Gibraltar replenishes the Mediterranean with Atlantic waters through an intense eastward current known as the Atlantic Jet (AJ). The AJ fertilizes the southwestern Mediterranean and is considered to be the ultimate factor responsible for the comparatively high fish production of this region. Here, we perform an analysis of the available historical catches and catch per unit effort (CPUE), together with a long series of surface currents, kinetic energy and chlorophyll concentration. We show that the high kinetic energy of the AJ increases primary production but also negatively impacts the recruitment of anchovy. We contend that anchovy recruitment in the region is inhibited by the advection and dispersion of larvae and post-larvae during periods of strong advection by the AJ. The inhibitory impact of kinetic energy on anchovy landings is not a transient but rather a persistent state of the system. An exceptional combination of events creates an outbreak of this species in the Alboran Sea. These events depend on the Mediterranean-Atlantic exchange of water masses and, therefore, are highly sensitive to climate changes that are projected, though not always negatively, for fish landings. PMID:23451027

The Spanish press associations, a consolidated model of professional organization / Las asociaciones de la prensa españolas, un modelo de organización profesional consolidado

Directory of Open Access Journals (Sweden)

Francisco Javier Paniagua Rojano - fjpaniagua@uma.es

2008-01-01

Full Text Available The Press Associations represent the prevailing organizational option among the Spanish journalists. At present, 50 Associations exist in Spain, specially limited to the provincial areas, but also to villages (Jerez de la Frontera, Talavera de la Reina, Santiago de Compostela, to shires (Campo de Gibraltar and even to regions, v. gr., the Unión de Periodistas Valencianos (Valencian Journalists Union. Likewise, there exist five specialized Associations; the most outstanding are the Asociación de Periodistas de Información Económica (Economic Information Association and the Asociación Española de la Prensa Deportiva (Sport Press Spanish Association. All the Associations are gathered into the Federación de Asociaciones de la Prensa de España (Federation of Spanish Press Associations. The present investigation analyzes level organization and syndication of Spanish journalists, the problems that affect to the professionals and the advantages derived from the belonging, offering information about: - Number of partners and trends registered in numbers. - Varied range of services to the professionals: the agreements with public and private corporations, labor exchanges, formative courses, paper an online magazines, etc.- Problems that affect to the professionals: the fight against working without qualification, the defense of the profession image and its values, etc. - Presence in Internet and adjustment to the new technologies.Resumen: Las asociaciones de la prensa representan la opción organizativa predominante entre los periodistas españoles. Suman, en la actualidad, un total de 50, la mayoría de ámbito provincial, aunque también las hay circunscritas a municipios (Jerez de la Frontera, Talavera de la Reina, Santiago de Compostela, a regiones (Campo de Gibraltar e incluso a comunidades autónomas, como la Unión de Periodistas Valencianos. De igual manera, existen cinco asociaciones de carácter especializado, como la Asociación de

Generation of deterministic tsunami hazard maps in the Bay of Cadiz, south-west Spain

Science.gov (United States)

Álvarez-Gómez, J. A.; Otero, L.; Olabarrieta, M.; González, M.; Carreño, E.; Baptista, M. A.; Miranda, J. M.; Medina, R.; Lima, V.

2009-04-01

The bay of Cádiz is a densely populated and industrialized area, and an important centre of tourism which multiplies its population in the summer months. This bay is situated in the Gulf of Cádiz, the south-west Atlantic margin of the Iberian Peninsula. From a tectonic point of view this area can be defined as a diffuse plate boundary, comprising the eastern edge of the Gloria and Tydeman transforms (where the deformation is mainly concentrated in these shear corridors), the Gorringe Bank, the Horseshoe Abyssal plain, the Portimao and Guadalquivir banks, and the western termination of the arcuated Gibraltar Arc. This deformation zone is the eastern edge of the Azores - Gibraltar seismic zone, being the present day boundary between the Eurasian and African plates. The motion between the plates is mainly convergent in the Gulf of Cádiz, but gradually changes to almost pure transcurrent along the Gloria Fault. The relative motion between the two plates is of the order of 4-5 mm/yr. In order to define the different tsunamigenic zones and to characterize its worst tsunamigenic source we have used seismic, structural and geological data. The numerical model used to simulate the wave propagation and coastal inundation is the C3 (Cantabria, COMCOT and Tsunami-Claw) model. C3 is a hybrid finite difference-finite volume method which balances between efficiency and accuracy. For offshore domain in deep waters the model applies an explicit finite difference scheme (FD), which is computationally fast and accurate in large grids. For near coast domains in coastal areas, it applies a finite volume scheme (VOF). It solves correctly the bore formation and the bore propagation. It is very effective solving the run-up and the run down. A set of five worst case tsunamigenic sources has been used with four different sea levels (minimum tide, most probable low tide, most probable high tide and maximum tide), in order to produce the following thematic maps with the C3 model: maximum

Ebusus Phoenissa et Poena : la isla de Ibiza en época fenicio-púnica

Directory of Open Access Journals (Sweden)

Benjamí Costa

1997-01-01

Full Text Available Los resultados de las investigaciones arqueológicas realizadas en Ibiza en los últimos veinticinco años, permiten concluir que el proceso de colonización de la isla se desarrolló en dos fases claramente diferenciadas: El primer establecimiento semita fue realizado en el siglo vii a.C. por fenicios occidentales y se vincula a la expansión del círculo colonial del Estrecho de Gibraltar. El segundo, supuso el asentamiento en Ibiza de contingentes púnicos de población, desde fines del siglo vi y sobre todo durante el V a.C. Este hecho, junto al desarrollo de la población existente, hizo posible la ocupación de toda la isla que, además de ser un importante puerto comercial, pasa a ser también un centro productor y exportador, a la vez que quedará vinculada al ámbito púnico liderado por Cartago. De esta manera, en la isla se forjará una formación social púnico-ebusitana que, en los siglos siguientes, experimentará un notable desarrollo. Tras la segunda Guerra Púnica, Ibiza quedará bajo dominio romano como ciudad federada, iniciando entonces un largo proceso evolutivo, que la llevará a integrarse plenamente en el Imperio, como municipio latino, en el siglo i d.C.The archaeological research carried out in Ibiza in the last twenty five years allows US to conclude that the process of the island's colonization in Antiquity took place in two clearly different phases: The first semitic settiement was undertaken by western Phoenicians and was related to the expansión of the colonial circle of the Straits of Gibraltar in the 7th century B.C.. The second one, from the end of the 6th century and throughout the 5th century B.C., gave rise to the establishment in Ibiza of new groups of Punic settiers. This fact, together with the growth of the existing population, made possible an important urban development and the occupation of the whole of the island. In this way, Ibiza, besides being a trading port, became also an important producer and

First record of Caulerpa cylindracea (Caulerpaceae, Chlorophyta in Andalusia (Southern Spain

Directory of Open Access Journals (Sweden)

Altamirano, María

2014-12-01

Full Text Available Three different species of Caulerpa (Caulerpaceae, Chlorophyta co-occur in the Mediterranean Sea: two of them are found at the central-eastern basin and are typically considered non aggressive components of the Lessepsian flora [(C. chemnitzia(Esper J.V. Lamouroux and C. racemosa var. lamourouxii (Turner Weber-van Bosse f. requienii(Montagne Weber van Bosse]; a third taxon, C. cylindracea Sonder has aggressively expanded its range since its first observation in 1990, and it is nowadays reported from nearly all the Mediterranean countries. We report a population of C. cylindracea from Almería (Andalusia, Southern Iberian Peninsula at −30 m depth as to be the westernmost record of the invasive variety on the Mediterranean European coast. Therefore, we made use of morphological description and molecular phylogenetics to provide a complete identification of this invasive seaweed in Southern Spain. Our findings are discussed in light of the composition of the receptor communities, such as maërl bed, edges of Posidonia oceanica (Linnaeus Delile, and their ecology. Our results confirmed the suggested directionality of the invasive pathway to be westward to the Strait of Gibraltar, mainly supported by sea currents and vectors of anthropogenic origin.En el Mar Mediterráneo se encuentran tres especies diferentes de Caulerpa (Caulerpaceae, Chlorophyta: dos de ellas se localizan en la cuenca centro oriental y se consideran componentes no agresivos de la flora Lessepsiana (C. chemnitzia(Esper J.V. Lamouroux and C. racemosa var. lamourouxii (Turner Weber-van Bosse f. requienii(Montagne Weber van Bosse; un tercer taxon, C. cylindracea Sonder ha expandido de manera agresiva su rango de distribución desde su primera observación en 1990, y actualmente se registra en casi todos los países de la cuenca mediterránea. En este trabajo se informa sobre una población de C. cylindracea en Almería (Andalucía, Sur de España, a −30 m de profundidad, que

The Contribution of the Topo-Iberia Project to the Knowledge of the Western Mediterranean Geodynamics.

Science.gov (United States)

Diaz Cusi, J.

2012-12-01

The large scale research program Topo-Iberia aims to unravel the complex structure and mantle processes in the area of interaction between the African and European continental plates in the western Mediterranean. The project, funded by the Spanish Ministry of Science and Education, started in 2007 and will be active till Fall 2013. Topo-Iberia has gathered expertise of different fields of the Earth Sciences. One of the key assets of the project involves the deploying of a technological observatory platform, IberArray, with unprecedented resolution and coverage. This platform is currently building up a comprehensive, multidisciplinary data set, stored by the SIGEOF database, which includes seismological, GPS and magnetotelluric data. Using also other analytical methodologies included in the Topo-Iberia program (potential fields, quantitative analysis of the topography, dating methods) the final scope of the project is to study the relationship between superficial and deep-rooted processes. Topo-Iberia has also benefited from the interaction with other projects investigating the same area, as the American program PICASSO, the French Pyrope or the Portuguese WILAS. This interaction includes sharing the available data to better assess the key geological questions. This contribution will present the current state of the most significant scientific results which are arising from the data acquired using the Iberarray platform. -. SKS splitting analysis has provided a spectacular image of the anisotropic pattern over the area, including a clear rotation of the fast velocity direction along the Gibraltar Arc. -. Receiver functions have revealed the crustal thickness variations beneath the Rif and southern Iberia, including a crustal root beneath the Rif not clearly documented previously. The 410-km and 660-km upper mantle discontinuities have been investigated using novel cross-correlation/stacking techniques. -. Surface wave tomography using both earthquakes and ambient

Evidence of a connection between the Atlantic and Mediterranean during the Messinian Salinity Crisis from Pb and Nd isotopes

Science.gov (United States)

Modestou, Sevasti; Gutjahr, Marcus; Fietzke, Jan; Rodés, Ángel; Frank, Martin; Bolhão Muiños, Susana; Ellam, Rob; Flecker, Rachel

2014-05-01

Prior to the opening of the Gibraltar Strait at 5.33 Ma, the Betic (southern Spain) and Rifian (northern Morocco) marine palaeocorridors linked the Mediterranean to the Atlantic. Although the central regions of these corridors have been heavily eroded due to uplift, evidence published to date indicates that both closed before the onset of the Messinian Salinity Crisis (MSC; 5.97 to 5.33 Ma [1, 2]). However, pre-MSC corridor closure presents a paradox, as the volume of halite deposited within the Mediterranean basin requires several times the volume of seawater contained in the basin itself. In this regard, radiogenic isotopes such as Sr, Pb, and Nd can provide key information about the timing of exchange through the Betic and Rifian palaeogateways. Due to the resolvable isotopic difference in Nd isotope signatures of outgoing Mediterranean and incoming Atlantic water masses, demonstrated both for the present day as well as the past environment, this isotope system can be used to identify exchange between these two water bodies. Although less well constrained to date, the Pb isotope system can be used in a similar manner due to its short residence time in seawater and interbasin variability. A high resolution Pb isotope record extracted using laser ablation from ferromanganese crust 3514-6 (recovered from the Lion Seamount, NE Atlantic, water depth 690-940 m) indicates a relatively constant Pb isotope signature before, during and after the MSC period. The previously published [3] Nd isotope record of crust 3514-6 corroborates that the crust was deposited in a current distinct from NE Atlantic Deep water or Antarctic Intermediate Water, the principal currents in the region of the Lion Seamount. The combined Pb and Nd isotope evolution suggests that Mediterranean Outflow Water (MOW) was continuously advected into the NE Atlantic during and after the MSC. Furthermore, preliminary Nd isotope records from Late Miocene sediments collected in the Sorbas Basin, Spain

Mineralogía y génesis de las arcillas de las unidades del Campo de Gibraltar. I. Areniscas del Aljibe

Directory of Open Access Journals (Sweden)

Ruiz Cruz, M. D.

1988-04-01

Full Text Available The «areniscas del Aljibe» are bimodal materials formed by eolic quartz with either clay or ferrous coatings and quartz sintaxial cemento The total mineralogical composition of the rocks and the fine fraction is very homogeneous in the sequences studied. The clay fraction is formed by kaolinite, illite and interstratified illite-5mectite. These minerals have variable origins, Thus, detritaI kaolinite pM and autbigenic kaolinite with high crystalinity are common, together with detrital illite and fibrous neoformed illite. Tbe smectite content of the mixed-layerd mineraIs suggests a different degree of diagenesis and a diverse paleogeographic situation for these sequences.Las «areniscas del Aljibe» son materiales bimodales constituidos en su mayor parte por cuarzos eólicos con «coating» ferruginoso o arcilloso y cemento de cuarzo sintaxial. Tanto la composición mineralógica de la muestra total como la de la fracción < 2 μ es muy homogénea en las secuencias estudiadas. La fracción fina está constituida por caoIinita, ilita e interestratificad I-E. En el desarrollo de estos minerales ha intervenido tanto la herencia (a partir de un área fuente homogénea como los procesos diagenéticos. De este modo, es frecuente encontrar desde caolinitas pM, heredadas, hasta caolinitas autigénicas de alta cristalinidad, incluso dentro de una misma muestra. De igual manera, además de láminas de ilita heredadas, son frecuentes las ilitas fibrosas neoformadas. Además, las características y composición de los interestratificados I-E han permitido deducir un diferente grado de diagénesis, así como una situación paleogeográfica diferente, para las dos columnas estudiadas, a pesar de su proximidad actual.

Mineralogía y génesis de las arcillas de las unidades del Campo de Gibraltar. IV. Unidad de Facinas

Directory of Open Access Journals (Sweden)

Ruiz Cruz, M. O.

1989-08-01

Full Text Available The Facinas Unit consists of a clayed flysch facies with quartzite and sandstone centimeter layers. According to paleontological data, two beds are distinguished, one lower of Albian-Aptian age, and another, hígher, Upper Cretaceous-Paleocene in age. The mineralogy of the Facinas Unit is very monotonous through all the sequences studied, especially for the concerning to less than 2 fraction. This unít is characterized by an abundance of chlorites of different composition and genesis: Authigenic chlorites are mainly Fe-rich members, whereas chlorites of inherited origin are magnesian. On the other hand, this míneralogical study reveals a common origin and/or evolution for the two beds of the Facinas Unít.Se recogen en este trabajo los resultados obtenidos a partir del estudio mineralógico de la Unidad de Facinas, que presenta dos tramos, uno inferior Albo-Aptense y otro superior Cretácico Superior-Paleoceno. Las secuencias estudiadas muestran una gran similitud litológica y, si bien en las muestras totales se observan ciertas diferencias mineralógicas, la fracción menor de 2 micras es muy homogénea. Caracterizan a esta Unidad la abundancia de cloritas de diferente composición y génesis: cloritas autigénicas, predominantemente ferrosas y cloritas heredadas, magnesianas. Por otra parte, este estudio mineralógico permite indicar un origen y/o evolución común para los dos tramos de la Unidad de Facínas.

Mineralogía y génesis de las arcillas de las unidades del Campo de Gibraltar. V. Unidad de Bolonia

Directory of Open Access Journals (Sweden)

Ruiz Cruz, M. D.

1990-04-01

Full Text Available The mineralogical results of the Bolonia Unit are analysed in the work. The Cabrito-l section is characterized by the mineralogical association kaolinite-illite-interestratified I-S, and is similar to the section of Punta Tarifa series of the Algeciras Unit. The Pulido section, characterized by the mineralogical association (kaolinite-illite-chlorite, may be considered as the most distal zone of the «areniscoso-micaceo» flysch of the Algeciras Unit. The most significant difference between the fine fractions of these Units is the remarkable development, in the Bolonia Unit, of authigenic chlorites, whose composition shows a diagenetic environment rich in Fe and Mg. On the other hand, the mineralogical composition of the fine fraction has made possible the identification in the Bolonia Unit, not only the «areniscas del Aljibe» levels, but also clay levels of Aljibe Unit, which has not been noticed until now. These mineralogical and lithological aspects lead to consider the Bolonia Unit as an intermediate Unit between the Algeciras and the Aljibe ones.En este trabajo se recogen los resultados obtenidos a partir del estudio mineralógico de la Unidad de Bolonia. De los perfiles estudiados, el del Cabrito, caracterizado por la asociación mineralógica caolinita-ilita, interestratificados I-E, es similar en gran medida a la serie tipo punta Tarifa de la Unidad de Algeciras. El perfil del Pulido, caracterizado por la asociación (caolinita-ilita-clorita puede interpretarse como la parte más distal del flysch areniscoso-micáceo de la Unidad de Algeciras. La diferencia más notable en la mineralogía de la fracción fina entre ambas Unidades se refiere al desarrollo notable, en Bolonia, de cloritas autigénicas, cuya composición indica un medio diagenético rico en Fe y Mg. Por otra parte, la mineralogía de la fracción fina ha permitido identificar en la Unidad de Bolonia no sólo los niveles de areniscas del Aljibe sino también, intercalaciones arcillosas de esta Unidad que hasta el momento no habían sido citadas. Estos aspectos mineralógicos y litológicos permiten considerar la Unidad de Bolonia como intermedia entre la Unidad de Algeciras y del Aljibe.

Forecasting of UV-Vis absorbance time series using artificial neural networks combined with principal component analysis.

Science.gov (United States)

Plazas-Nossa, Leonardo; Hofer, Thomas; Gruber, Günter; Torres, Andres

2017-02-01

This work proposes a methodology for the forecasting of online water quality data provided by UV-Vis spectrometry. Therefore, a combination of principal component analysis (PCA) to reduce the dimensionality of a data set and artificial neural networks (ANNs) for forecasting purposes was used. The results obtained were compared with those obtained by using discrete Fourier transform (DFT). The proposed methodology was applied to four absorbance time series data sets composed by a total number of 5705 UV-Vis spectra. Absolute percentage errors obtained by applying the proposed PCA/ANN methodology vary between 10% and 13% for all four study sites. In general terms, the results obtained were hardly generalizable, as they appeared to be highly dependent on specific dynamics of the water system; however, some trends can be outlined. PCA/ANN methodology gives better results than PCA/DFT forecasting procedure by using a specific spectra range for the following conditions: (i) for Salitre wastewater treatment plant (WWTP) (first hour) and Graz West R05 (first 18 min), from the last part of UV range to all visible range; (ii) for Gibraltar pumping station (first 6 min) for all UV-Vis absorbance spectra; and (iii) for San Fernando WWTP (first 24 min) for all of UV range to middle part of visible range.

Population structure of Cicada barbara Stål (Hemiptera, Cicadoidea) from the Iberian Peninsula and Morocco based on mitochondrial DNA analysis.

Science.gov (United States)

Pinto-Juma, G A; Quartau, J A; Bruford, M W

2008-02-01

We assess the genetic history and population structure of Cicada barbara in Morocco and the Iberian Peninsula, based on analysis of the mitochondrial cytochrome b gene. The divergence between Morocco and the Iberian Peninsula populations was strongly corroborated by the molecular data, suggesting genetically isolated populations with a low level of gene flow. The Ceuta population from Spanish North Africa was more similar to the Iberian populations than the surrounding Moroccan populations, suggesting that the Strait of Gibraltar has not been acting as a strict barrier to dispersal while the Rif Mountains have. The Iberian Peninsula specimens showed a signature of demographic expansion before that which occurred in Morocco, but some of the assumptions related to the demographic parameters should be considered with caution due to the small genetic variation found. The high haplotype diversity found in Morocco implies higher demographic stability than in the Iberian Peninsula populations. These results do not, however, suggest a Moroccan origin for Iberian cicadas; but the most northwest region in Africa, such as Ceuta, might have acted as a southern refuge for Iberian cicadas during the most severe climatic conditions, from where they could expand north when climate improved. The separation of two subspecies within C. barbara (C. barbara lusitanica and C. barbara barbara) finds support with these results.

The Mediterranean Oscillation Teleconnection Index: Station-Based versus Principal Component Paradigms

Directory of Open Access Journals (Sweden)

Francisco Criado-Aldeanueva

2013-01-01

Full Text Available Two different paradigms of the Mediterranean Oscillation (MO teleconnection index have been compared in this work: station-based definitions obtained by the difference of some climate variable between two selected points in the eastern and western basins (i.e., Algiers and Cairo, Gibraltar and Israel, Marseille and Jerusalem, or south France and Levantine basin and the principal component (PC approach in which the index is obtained as the time series of the first mode of normalised sea level pressure anomalies across the extended Mediterranean region. Interannual to interdecadal precipitation (P, evaporation (E, E-P, and net heat flux have been correlated with the different MO indices to compare their relative importance in the long-term variability of heat and freshwater budgets over the Mediterranean Sea. On an annual basis, the PC paradigm is the most effective tool to assess the effect of the large-scale atmospheric forcing in the Mediterranean Sea because the station-based indices exhibit a very poor correlation with all climatic variables and only influence a reduced fraction of the basin. In winter, the station-based indices highly improve their ability to represent the atmospheric forcing and results are fairly independent of the paradigm used.

Using Seasonal Forecasting Data for Vessel Routing

Science.gov (United States)

Bell, Ray; Kirtman, Ben

2017-04-01

We present an assessment of seasonal forecasting of surface wind speed, significant wave height and ocean surface current speed in the North Pacific for potential use of vessel routing from Singapore to San Diego. WaveWatchIII is forced with surface winds and ocean surface currents from the Community Climate System Model 4 (CCSM4) retrospective forecasts for the period of 1982-2015. Several lead time forecasts are used from zero months to six months resulting in 2,720 model years, ensuring the findings from this study are robust. July surface wind speed and significant wave height can be skillfully forecast with a one month lead time, with the western North Pacific being the most predictable region. Beyond May initial conditions (lead time of two months) the El Niño Southern Oscillation (ENSO) Spring predictability barrier limits skill of significant wave height but there is skill for surface wind speed with January initial conditions (lead time of six months). In a separate study of vessel routing between Norfolk, Virginia and Gibraltar we demonstrate the benefit of a multimodel approach using the North American Multimodel Ensemble (NMME). In collaboration with Charles River Analytics an all-encompassing forecast is presented by using machine learning on the various ensembles which can be using used for industry applications.

Modelling the water and heat balances of the Mediterranean Sea using a two-basin model and available meteorological, hydrological, and ocean data

Directory of Open Access Journals (Sweden)

Mohamed Shaltout

2015-04-01

Full Text Available This paper presents a two-basin model of the water and heat balances of the Western and Eastern Mediterranean sub-basins (WMB and EMB, respectively over the 1958–2010 period using available meteorological and hydrological data. The results indicate that the simulated temperature and salinity in both studied Mediterranean sub-basins closely follow the reanalysed data. In addition, simulated surface water in the EMB had a higher mean temperature (by approximately 1.6°C and was more saline (by approximately 0.87 g kg−1 than in the WMB over the studied period. The net evaporation over the EMB (1.52 mm day−1 was approximately 1.7 times greater than over the WMB (0.88 mm day−1. The water balance of the Mediterranean Sea was controlled by net inflow through the Gibraltar Strait and Sicily Channel, the net evaporation rate and freshwater input. The heat balance simulations indicated that the heat loss from the water body was nearly balanced by the solar radiation to the water body, resulting in a net export (import of approximately 13 (11 W m−2 of heat from the WMB (to the EMB.

Evolution of nuclear weapon-produced tritium and its decay product He-3 in the Mediterranean Sea, 1952-2011

Energy Technology Data Exchange (ETDEWEB)

Roether, Wolfgang [IUP Univ. Bremen (Germany)

2015-07-01

After 1952, tritium in the Mediterranean Sea (Med) rose 100-fold up to a 30 TU peak in 1965 (1 TU = [H-3/H] . 10{sup 18}) and thereafter declined to about 1 TU in 2011. This resulted in a strong supply of its stable daughter He-3, concentrated in the 1960s. Terrigenic He being low in He-3 due to a predominantly crustal origin allowed precise determination of the tritiugenic He-3 (± 0.7% in delta He-3). The highest He-3 was found off the Tyrrhenian Sea in 1983 (delta He-3 ∝ 16%). The principle input into the subsurface waters occurs in the Eastern Med by way of the Levantine Intermediate Water (LIW), which moves as a high-salinity core westward toward the Strait of Gibraltar. The observations demonstrate strong longitudinal flow dispersion. As tritium-He-3 ages are biased toward times of strong input, one finds an age increase with calendar year of observation, attributed to fast flow contributions showing up first. A realistic estimate for transfer from the LIW source up to the Western Med is 22 years. Especially in the East, He-3 lately decreased distinctly, in response to the reduced He-3 generation.

[Perceptions and experiences of access to health services and their utilization among the immigrant population].

Science.gov (United States)

Bas-Sarmiento, Pilar; Fernández-Gutiérrez, Martina; Albar-Marín, M A Jesús; García-Ramírez, Manuel

2015-01-01

To identify and describe the needs and problems of the immigrant population related to access and utilization of health services. A descriptive, qualitative, phenomenological study was conducted using focus groups. The study area was the county of Campo de Gibraltar (Spain), which represents the gateway to Europe for immigration from Africa. The final sample size (51 immigrants from 11 countries) was determined by theoretical saturation. A narrative analysis was conducted with QSR NVivo9 software. Immigrants' discourse showed four categories of analysis: response to a health problem, system access, knowledge of social and health resources, and health literacy needs. Responses to health problems and the route of access to the health care system differed according to some sociodemographic characteristics (nationality/culture of origin, length of residence, and economic status). In general, immigrants primarily used emergency services, hampering health promotion and prevention. The health literacy needs identified concerned language proficiency and the functioning of the health system. There is a need to promote interventions to enhance health literacy among immigrants. These interventions should take into account diversity and length of residence, and should be based on an action-participation methodology. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

New constraints on the evolution of the Gibraltar Arc from palaeomagnetic data of the Ceuta and Beni Bousera peridotites (Rif, northern Africa)

Science.gov (United States)

Berndt, Thomas; Ruiz-Martínez, Vicente Carlos; Chalouan, Ahmed

2015-03-01

The Betic Cordillera and the Moroccan Rif together form one of the smallest and tightest orogenic arcs on Earth and almost completely close the Mediterranean to the west. For the explanation of the geodynamic evolution of the mountain belt, palaeomagnetic data that generally found clockwise block rotations in the Iberian and anticlockwise rotations in the Moroccan part of the mountain belt, have played a key role in recent works. This palaeomagnetic study has found new constraints on the rotations and timing of the peridotitic bodies outcropping in the key position at the westernmost margin of the mountain belt, in Ceuta and Beni Bousera (Rif, northern Africa). Detailed thermal demagnetization of 115 individually oriented samples from 14 sites was combined with rock magnetic and scanning electron microscopic experiments to analyze the magnetic mineralogy responsible for the remanences and the mechanisms and relative times of their acquisition. In Ceuta, up to three magnetic components, and in Beni Bousera, up to two magnetic components have been found, that are all to be interpreted as chemical remanent magnetizations (CRM). The data suggests the following succession of geodynamic events affecting the peridotites until recent times: (1) after their exhumation and subsequent cooling about 20 Ma ago, they recorded a characteristic remanent magnetization of both normal and reversed polarities, carried by (pseudo-)single-domain magnetite grains; (2) after their dismembering, the Ceuta peridotites were tilted southward by 22-34° about a horizontal or tilted axis (up to plunge 50°) with an azimuth of 72-145° and the Beni Bousera peridotites were rotated anticlockwise by 72.3 ± 12.1° about a vertical axis and (3) both recorded another magnetic signal of normal polarity only, carried by multi-domain magnetite grains; and finally (4) the Ceuta peridotites rotated anticlockwise by 19.7 ± 5.9° about a vertical axis. This study provides the first palaeomagnetic data for the Ceuta peridotites that, with their tilt and recent small net rotation, had a distinct geodynamic evolution from the large net rotations about vertical axes in Beni Bousera and Ronda (Betic Cordillera). Moreover, earlier palaemagnetic data for Beni Bousera is improved, as mixed polarities have been found in the older of the remanences for the first time, and its interpretation as a CRM changes the rotation timing that was proposed previously. The sequence of events exposed in this work are important constraints that need to be incorporated in any geodynamic model of the evolution of the Betic-Rifean mountain belt.

Oceanographic Mower Cruise

Science.gov (United States)

Valencia, J.; Ercilla, G.; Hernández-Molina, F. J.; Casas, D.

2015-04-01

The MOWER Cruise has executed a geophysics and geologic expedition in the Gulf of Cádiz (sector adjacent to the Strait of Gibraltar) and west off Portugal, in the framework of the coordinate research project MOWER "Erosive features and associated sandy deposits generated by the Mediterranean Outflow Water (MOW) around Iberia: paleoceanographic, sedimentary & economic implications" (CTM 2012-39599-C03). The main aim of this project is to identify and study the erosional features (terraces and channels) and associated sedimentary deposits (sandy contourites) generated by the Mediterranean Water Masses around the middle continental slope of Iberia (The Mediterranean Outflow Water - MOW - in the Atlantic margins), their Pliocene and Quaternary evolution and their paleoceanographic, sedimentary and economic implications. This objective directly involves the study of alongslope (contourite) processes associated with the MOW and across-slope (turbiditic flows, debris flows, etc.) processes in the sedimentary stacking pattern and evolution of the Iberian margins. The MOWER project and cruise are related to the Integrated Ocean Drilling Program (IODP) Expedition 339 (Mediterranean Outflow). It is also linked and coordinated with CONDRIBER Project "Contourite drifts and associated mass-transport deposits along the SW Iberia margin - implications to slope stability and tsunami hazard assessment" (2013-2015) funded by the Fundação para a Ciência e Tecnologia, Portugal (PTDC/GEO-GEO/4430/2012).

Vertical distribution and seasonality of peracarid crustaceans associated with intertidal macroalgae

Science.gov (United States)

Guerra-García, J. M.; Baeza-Rojano, E.; Cabezas, M. P.; García-Gómez, J. C.

2011-02-01

Spatial patterns and seasonal fluctuations of intertidal peracarids from Tarifa Island, Strait of Gibraltar, were studied over a two-year period (December 2005-December 2007). A total of 25,749 individuals were collected, comprising 46 species. Amphipods were best represented in the total number of species (32) and individuals (89% of numerical abundance) followed by isopods (12 species and 11% abundance) and tanaids (2 species and 1%). The highest number of species was registered in intermediate levels (1-1.5 m) dominated by Corallina elongata, although the highest abundances of peracarids were associated to seaweeds of lower levels (0-1 m) such as Gelidium corneum, Osmundea pinnatifida, Valonia utricularis and a turf of Caulacanthus ustulatus. The most abundant peracarids, Hyale stebbingi, H. schmidti, H. perieri, Stenothoe monoculoides, Caprella penantis, C. grandimana, Dynamene edwardsii and Ischyromene lacazei, were present throughout the whole year during 2006 and 2007. The highest peracarid densities were measured in April-August coinciding with the highest development of seaweeds, just before the maximum values of water temperature measured at the end of summer. Multivariate analyses confirmed a clear zonation of algae and associated peracarids in a vertical gradient, which was maintained stable during the two-year study. Several physical and biological factors may regulate such patterns of peracarid abundance and future experimental studies are necessary to explore the importance of factors such as competition, predation or weather conditions.

Analysis of the balancing of the wind and solar energy resources in Andalusia (Southern Spain)

Science.gov (United States)

Santos-Alamillos, F. J.; Pozo-Vazquez, D.; Lara-Fanego, V.; Ruiz-Arias, J. A.; Hernandez-Alvaro, J.; Tova-Pescador, J.

2010-09-01

A higher penetration of the renewable energy in the electric system in the future will be conditioned to a reduction of the uncertainty of the yield. A way to obtain this goal is to analyze the balancing between the productions of different sources of renewable energy, trying to combine these productions. In this work we analyze, from a meteorological point of view, the balancing between wind and solar energy resources in Andalusia (southern Iberian Peninsula). To this end, wind speed and global radiation data corresponding to an one year integration of the Weather Research and Forecasting (WRF) Numerical Weather Prediction (NWP) model were analyzed. Two method of analysis were used: a point correlation analysis and a Canonical Correlation Analysis (CCA). Results from these analyses allow obtaining, eventually, areas of local and distributed balancing between the wind and solar energy resources. The analysis was carried out separately for the different seasons of the year. Results showed, overall, a considerable balancing effect between the wind and solar resources in the mountain areas of the interior of the region, along the coast of the central part of the region and, specially, in the coastal area near the Gibraltar strait. Nevertheless, considerable differences were found between the seasons of the year, which may lead to compensating effects. Autumn proved to be the season with the most significant results.

The fishing area as a possible indicator of the infection by anisakids in anchovies (Engraulis encrasicolus) from southwestern Europe.

Science.gov (United States)

Rello, Francisco Javier; Adroher, Francisco Javier; Benítez, Rocío; Valero, Adela

2009-02-28

A study was conducted on the parasitization by anisakids of European anchovies (Engraulis encrasicolus) from the Eastern Atlantic (Gulf of Cádiz and Strait of Gibraltar) and Western Mediterranean (Ligurian Sea, Gulf of Lion, Catalonia coast and NW Alborán Sea) throughout 1998 and 1999. The anisakids detected were identified as third larval stages of Anisakis larva type I and Hysterothylacium aduncum. Global prevalence was 9.4% for Anisakis and 24.5% for H. aduncum. Analysis of the origin of the anchovies revealed a higher prevalence of Anisakis than H. aduncum in fish from the Atlantic and vice-versa in fish from the Mediterranean. Analysis of various fishing areas in the Western Mediterranean revealed a prevalence of Anisakis in fish from the Ligurian Sea that was 5-fold or more than in the other three areas, with a significantly greater prevalence of H. aduncum in fish from the NW Mediterranean than from the Spanish Mediterranean coast. The prevalence of infection was found to be significantly related to anchovy length for both Anisakis and H. aduncum. More than 55% of Anisakis larvae were found in the muscle. According to these data, the risk of acquiring anisakiasis/anisakidosis from the consumption of raw or under-cooked anchovies may depend upon the area in which they were caught.

Early signs of geodynamic activity before the 2011-2012 El Hierro eruption

Science.gov (United States)

López, Carmen; García-Cañada, Laura; Martí, Joan; Domínguez Cerdeña, Itahiza

2017-04-01

The potential relation between mantle plume dynamics, regional tectonics and eruptive activity in the Canary Islands has not been studied yet through the analysis of long-time series of geophysical observational data. The existence of highly reliable seismic and GNSS data has enabled us to study from 1996 to 2014 the geodynamic evolution of the North Atlantic Azores-Gibraltar region and its relationship with recent volcanic activity in El Hierro (Canary Islands, Spain). We compiled a new and unified regional seismic catalog and used long time-series of surface displacements recorded by permanent GNSS stations in the region. A regional- and local-scale analysis based on these data enabled us to identify signs of anomalous tectonic activity from 2003 onwards, whose intensity increased in 2007 and finally accelerated three months before the onset of the volcanic eruption on El Hierro in October 2011. This activity includes a regional extension and an uplift process that affects the southern Iberian Peninsula, NW Africa, and the Canary Islands. We interpret these observations as early signs of the geodynamic activity, which led to El Hierro eruption and the subsequent episodes of magma intrusion. Results point to the significant contribution of the mantle plume dynamics (i.e. external forces) in this renewed volcanic activity in the Canary Islands and emphasize the role of mantle dynamics in controlling regional tectonics.

The Mediterranean Sea system: a review and an introduction to the special issue

Directory of Open Access Journals (Sweden)

T. Tanhua

2013-09-01

Full Text Available The Mediterranean Sea is a semi-enclosed sea characterized by high salinities, temperatures and densities. The net evaporation exceeds the precipitation, driving an anti-estuarine circulation through the Strait of Gibraltar, contributing to very low nutrient concentrations. The Mediterranean Sea has an active overturning circulation, one shallow cell that communicates directly with the Atlantic Ocean, and two deep overturning cells, one in each of the two main basins. It is surrounded by populated areas and is thus sensitive to anthropogenic forcing. Several dramatic changes in the oceanographic and biogeochemical conditions have been observed during the past several decades, emphasizing the need to better monitor and understand the changing conditions and their drivers. During 2011 three oceanographic cruises were conducted in a coordinated fashion in order to produce baseline data of important physical and biogeochemical parameters that can be compared to historic data and be used as reference for future observational campaigns. In this article we provide information on the Mediterranean Sea oceanographic situation, and present a short review that will serve as background information for the special issue in Ocean Science on "Physical, chemical and biological oceanography of the Mediterranean Sea". An important contribution of this article is the set of figures showing the large-scale distributions of physical and chemical properties along the full length of the Mediterranean Sea.

Integrating microsatellite DNA markers and otolith geochemistry to assess population structure of European hake (Merluccius merluccius)

Science.gov (United States)

Tanner, Susanne E.; Pérez, Montse; Presa, Pablo; Thorrold, Simon R.; Cabral, Henrique N.

2014-04-01

Population structure and natal origins of European hake were investigated using microsatellite DNA markers and otolith geochemistry data. Five microsatellites were sequenced and otolith core geochemical composition was determined from age-1 hake collected in the northeast Atlantic Ocean and the Mediterranean Sea. Microsatellites provided evidence of a major genetic split in the vicinity of the Strait of Gibraltar, separating the Atlantic and the Mediterranean populations, with the exception of the Gulf of Cádiz. Based on classification models using otolith core geochemical values, individual natal origins were identified, although with an increased error rate. Coupling genotype and otolith data increased the classification accuracy of individuals to their potential natal origins while providing evidence of movement between the northern and southern stock units in the Atlantic Ocean. Information obtained by the two natural markers on population structure of European hake was complementary as the two markers act at different spatio-temporal scales. Otolith geochemistry provides information over an ecological time frame and on a fine spatial scale, while microsatellite DNA markers report on gene flow over evolutionary time scales and therefore act on a broader spatio-temporal resolution. Thus, this study confirmed the value of otolith geochemistry to complement the assessment of early life stage dispersal in populations with high gene flow and low genetic divergence.

From Gibraltar through Levant and from Maghreb through the Southern Latin European Countries or about culture and management in the Mediterranean Sea Region

Directory of Open Access Journals (Sweden)

Amedeo ISTOCESCU

2010-06-01

Full Text Available Bordering the southern coast of Europe, the eastern part of the Middle East and northern Africa, representing the most appropriate environment for the development of cultural, social and economic of the maritime regions, influencing decisively the culture and the entire life of the inhabitants in a lot of bordering countries, ensuring the achievement of a natural maritime transportation way between eastern Levantine character and western pragmatism of our ancient continent, or between Maghreb, and the Latin world, especially in southern Europe, the Mediterranean Sea has an another treasure, yet poorly known and only partially recovered, with a history of over six thousands of years, with people proud of their history, culture, customs and traditions with unique cities, impressive by the mixture of cultures and races, its islands

Structure of Sierra Blanca (Alpujarride Complex, west of the Betic Cordillera

Directory of Open Access Journals (Sweden)

Andreo, B.

1995-04-01

Full Text Available Sierra Blanca, situated in the SW of Málaga, forms part of the Blanca unit, belonging to the Alpujarride Complex of the Betic Cordillera. Its lithologic sequences are made up of a group of migmatites, gneisses and schists and an upper formation of marbles (white dolomitic and the bottom and blue calcareous towards the top, linked with a transitional contact. The structure of Sierra Blanca is comprised of folds, generally isoclinal, with reversed limbs and with important tectonic transpositions, the direction of which is approximately E-W in the eastern area and N-S and E-W in the West. In both areas the folds present opposing vergences, consistently towards the interior of the sierra. The origin of these structures is explained with a model of westerly movements of the Blanca unit, in relation to the Los Reales unit, with the formation of frontal and lateral folds. In its advancement, the western part of Sierra Blanca underwent an important anti-clockwise rotation responsible for the co-existence of folds in N-S and E-W directions. These structures occurred under ductile conditions, owing to the presence of important overthrusting peridotitic masses of the Los Reales unit. This model of westerly displacement is inserted in the process undergone by the Betic-Rif Internal Zones (with Blanca and Los Reales units included which occurred at the end of the Oligocene-Early Miocene when the Gibraltar arch began to be formed.Sierra Blanca, situada al SW de Málaga, forma parte de la unidad de Blanca que pertenece al complejo Alpujárride de la Cordillera Bética. Su secuencia litológica está compuesta por un conjunto inferior de migmatitas, gneises y esquistos, y por una formación superior de mármoles, blancos dolomíticos en la base y mármoles calizos azules hacia la parte superior, entre los que existe un tránsito gradual. La estructura de Sierra Blanca está formada por pliegues, generalmente isoclinales, con flancos invertidos que muestran

La aplicación de la libertad religiosa en Cádiz durante el Sexenio Democrático en relación con los protestantes (1868-1874

Directory of Open Access Journals (Sweden)

Antonio Orozco Guerrero

2012-01-01

Full Text Available A partir de 1835, los periodos intermitentes de tolerancia política en España parecían abrir las posibilidades para la difusión de las doctrinas protestantes. En Cádiz esta se desarrolló en buena parte a causa de la proximidad de Gibraltar, siendo llevada a cabo fundamentalmente por pastores ingleses enviados por la Sociedad Bíblica Británica y Extranjera. Los sucesivos intentos fracasaron por la intolerancia de las autoridades locales civiles y religiosas. La revolución española de 1868, con la declaración de la libertad de cultos inserta en la Constitución de 1869, anunciaba una extensión de la Reforma en la ciudad de Cádiz. Pero el clero católico se mostró muy crítico con la libertad de cultos y algún sacerdote católico dirigió escritos muy severos contra las creencias de los protestantes y contra los pastores locales, a modo de propaganda que hiciera desistir a sus seguidores. Por su parte, el obispo de la diócesis trató de fomentar la creación y mejora de escuelas privadas católicas para contrarrestar el previsible auge protestante. La realidad no confirmó las expectativas de los evangélicos, que en la práctica siguieron teniendo algunas dificultades para manifestar su religiosidad en público. Su situación empeoró cuando se cerró el cementerio anglicano y los no católicos volvieron a ser enterrados en condiciones poco dignas. La brevedad temporal de la Primera República no permitió afianzar medidas municipales como la secularización del cementerio municipal, que hubiera permitido enterrar allí a los protestantes.Since 1835, intermittent periods of political tolerance in Spain seemed to open up the possibilities for the spread of Protestant doctrines. In Cadiz this was developed in large because of the proximity of Gibraltar, being carried out mainly by British ministers sent by the British and Foreign Bible Society. Successive attempts failed due to the intolerance of the civil and religious authorities

Searching for Seismically Active Faults in the Gulf of Cadiz

Science.gov (United States)

Custodio, S.; Antunes, V.; Arroucau, P.

2015-12-01

The repeated occurrence of large magnitude earthquakes in southwest Iberia in historical and instrumental times suggests the presence of active fault segments in the region. However, due to an apparently diffuse seismicity pattern defining a broad region of distributed deformation west of Gibraltar Strait, the question of the location, dimension and geometry of such structures is still open to debate. We recently developed a new algorithm for earthquake location in 3D complex media with laterally varying interface depths, which allowed us to relocate 2363 events having occurred from 2007 to 2013, using P- and S-wave catalog arrival times obtained from the Portuguese Meteorological Institute (IPMA, Instituto Portugues do Mar e da Atmosfera), for a study area lying between 8.5˚W and 5˚W in longitude and 36˚ and 37.5˚ in latitude. The most remarkable change in the seismicity pattern after relocation is an apparent concentration of events, in the North of the Gulf of Cadiz, along a low angle northward-dipping plane rooted at the base of the crust, which could indicate the presence of a major fault. If confirmed, this would be the first structure clearly illuminated by seismicity in a region that has unleashed large magnitude earthquakes. Here, we present results from the joint analysis of focal mechanism solutions and waveform similarity between neighboring events from waveform cross-correlation in order to assess whether those earthquakes occur on the same fault plane.

A high-resolution hydrodynamic-biogeochemical coupled model of the Gulf of Cadiz – Alboran Sea region.

Directory of Open Access Journals (Sweden)

D. M. MACIAS

2014-12-01

Full Text Available The southern Iberia regional seas comprise the Gulf of Cadiz and the Alboran Sea sub-basins connected by the narrow Strait of Gibraltar. Both basins are very different in their hydrological and biological characteristics but are, also, tightly connected to each other. Integrative studies of the whole regional oceanic system are scarce and difficult to perform due to the relative large area to cover and the different relevant time-scales of the main forcings in each sub-basin. Here we propose, for the first time, a fully coupled, 3D, hydrodynamic-biogeochemical model that covers, in a single domain (~2km resolution both marine basins for a 20 years simulation (1989-2008. Model performance is assessed against available data in terms of spatial and temporal distributions of biological variables. In general, the proposed model is able to represent the climatological distributions of primary and secondary producers and also the main seasonality of primary production in the different sub-regions of the analyzed basins. Potential causes of the observed mismatches between model and data are identified and some solutions are proposed for future model development. We conclude that most of these mismatches could be attributed to the missing tidal forcing in the actual model configuration. This model is a first step to obtain a meaningful tool to study past and future oceanographic conditions in this important marine region constituting the unique connection of the Mediterranean Sea with the open world’s ocean.

Vertical density gradient in the eastern North Atlantic during the last 30,000 years

Energy Technology Data Exchange (ETDEWEB)

Rogerson, M.; Ramirez, J. [University of Hull, Geography Department, Hull (United Kingdom); Bigg, G.R. [University of Sheffield, Department of Geography, Sheffield (United Kingdom); Rohling, E.J. [University of Southampton, National Oceanography Centre, School of Ocean and Earth Science, Southampton (United Kingdom)

2012-08-15

Past changes in the density and momentum structure of oceanic circulation are an important aspect of changes in the Atlantic Meridional Overturning Circulation and consequently climate. However, very little is known about past changes in the vertical density structure of the ocean, even very extensively studied systems such as the North Atlantic. Here we exploit the physical controls on the settling depth of the dense Mediterranean water plume derived from the Strait of Gibraltar to obtain the first robust, observations-based, probabilistic reconstruction of the vertical density gradient in the eastern North Atlantic during the last 30,000 years. We find that this gradient was weakened by more than 50%, relative to the present, during the last Glacial Maximum, and that changes in general are associated with reductions in AMOC intensity. However, we find only a small change during Heinrich Event 1 relative to the Last Glacial Maximum, despite strong evidence that overturning was substantially altered. This implies that millennial-scale changes may not be reflected in vertical density structure of the ocean, which may be limited to responses on an ocean-overturning timescale or longer. Regardless, our novel reconstruction of Atlantic density structure can be used as the basis for a dynamical measure for validation of model-based AMOC reconstructions. In addition, our general approach is transferrable to other marginal sea outflow plumes, to provide estimates of oceanic vertical density gradients in other locations. (orig.)

Total Organic Carbon Distribution and Bacterial Cycling Across A Geostrophic Front In Mediterranean Sea. Implications For The Western Basin Carbon Cycle

Science.gov (United States)

Sempere, R.; van Wambeke, F.; Bianchi, M.; Dafner, E.; Lefevre, D.; Bruyant, F.; Prieur, L.

We investigated the dynamic of the total organic carbon (TOC) pool and the role it played in the carbon cycle during winter 1997-1998 in the Almeria-Oran jet-front (AOF) system resulting from the spreading of Atlantic surface water through the Gibraltar Strait in the Alboran Sea (Southwestern Mediterranean Sea). We determined TOC by using high temperature combustion technique (HTC) and bacterial produc- tion (BP; via [3H] leucine incorporation) during two legs in the frontal area. We also estimated labile TOC (l-TOC) and bacterial growth efficiency (BGE) by performing TOC biodegradation experiments on board during the cruise whereas water column semi-labile (sl-TOC), and refractory-TOC were determined from TOC profile exami- nation. These results are discussed in relation with current velocity measured by using accoustic doppler current profiler (ADCP). Lowest TOC stocks (6330-6853 mmol C m-2) over 0-100 m were measured in the northern side of the geostrophic Jet which is also the highest dynamic area (horizontal speed of 80 cm s-1 in the first 100 m di- rected eastward). Our results indicated variable turnover times of sl-TOC across the Jet-Front system, which might be explained by different coupling of primary produc- tion and bacterial production observed in these areas. We also estimated TOC and sl-TOC transports within the Jet core off the Alboran Sea as well as potential CO2 production through bacterial respiration produced from sl-TOC assimilation by het- erotrophic bacteria.

Effect of water stress in soil-water-vegetation relationships, along a rainfall gradient in southern Spain

International Nuclear Information System (INIS)

Ruiz-Sinoga, J. D.; Ferre Bueno, E.; Martinez-Murillo, J. F.; Gabarron-Galeote, M. A.

2009-01-01

The Andalusian Mediterranean Watershed, in the South of the Iberian Peninsula, shows a climatic gradient from the Straits of Gibraltar (1,600 mm year - 1) to the Cabo de Gata (150 mm year 1 ). Climate conditions differences are translating into variations in the elements of the eco-geomorphologic system at hillslope scale. In this study has been analysed the immediate consequences of a period of two years drought (2004-06) on several elements of the Mediterranean eco-geomorphologic system at three hillslopes (sub-humid, dry Mediterranean and semi-arid). the soil water content, the pattern of vegetation and some soil properties (organic matter content, aggregate stability and permeability) were analysed before (Nov-2003) and during (Nov-2005) the drought period. Final results have shown: i) reduction in soil water content which reached in the wet seasons values below wilting point, affecting negatively to the water available for vegetation and especially in the wettest sites; ii) reduction in vegetation cover and in the number of plants, especially at semi-arid field site; iii) changes in the organic matter content which aggravates the loss of stability of soil aggregates, a process seen more clearly under more arid conditions; and iv) reduction of soil permeability in all situations in the climate gradient studied, which supposes a priori an increase in erosive processes due to surface runoff. These results indicate increased vulnerability of the eco-geomorphologic system because of the rainfall drought situation. (Author) 14 refs.

Effect of water stress in soil-water-vegetation relationships, along a rainfall gradient in southern Spain; Incidencia del stress hidrico en las relaciones suelo-agua-planta a lo largo de un gradiente pluviometrico en el sur de Espana

Energy Technology Data Exchange (ETDEWEB)

Ruiz-Sinoga, J. D.; Ferre Bueno, E.; Martinez-Murillo, J. F.; Gabarron-Galeote, M. A.

2009-07-01

The Andalusian Mediterranean Watershed, in the South of the Iberian Peninsula, shows a climatic gradient from the Straits of Gibraltar (1,600 mm year{sup -1}) to the Cabo de Gata (150 mm year{sup -1}). Climate conditions differences are translating into variations in the elements of the eco-geomorphologic system at hillslope scale. In this study has been analysed the immediate consequences of a period of two years drought (2004-06) on several elements of the Mediterranean eco-geomorphologic system at three hillslopes (sub-humid, dry Mediterranean and semi-arid). the soil water content, the pattern of vegetation and some soil properties (organic matter content, aggregate stability and permeability) were analysed before (Nov-2003) and during (Nov-2005) the drought period. Final results have shown: i) reduction in soil water content which reached in the wet seasons values below wilting point, affecting negatively to the water available for vegetation and especially in the wettest sites; ii) reduction in vegetation cover and in the number of plants, especially at semi-arid field site; iii) changes in the organic matter content which aggravates the loss of stability of soil aggregates, a process seen more clearly under more arid conditions; and iv) reduction of soil permeability in all situations in the climate gradient studied, which supposes a priori an increase in erosive processes due to surface runoff. These results indicate increased vulnerability of the eco-geomorphologic system because of the rainfall drought situation. (Author) 14 refs.

Transformaciones territoriales en el norte de Marruecos

Directory of Open Access Journals (Sweden)

Jesús Gabriel Moreno-Navarro

2011-12-01

Full Text Available Los miembros del equipo de cooperación internacional "Territorio Andaluz, Desarrollo e Innovación" se han implicado durante más de una década en proyectos de desarrollo sobre zonas colindantes con el Estrecho de Gibraltar. En este artículo se resume el perfil y las conclusiones obtenidas en los proyectos de cooperación desarrollados por el grupo, así como otros hechos relacionados con las transformaciones territoriales del Norte de Marruecos. En la actualidad, las acciones se basan en la construcción de grandes puertos y carreteras cercanas a los nuevos centros turísticos de la costa. Los impactos son evidentes en el medio ambiente y en el contexto social. La transformación radical ha aumentado el atractivo en las zonas urbanas, incrementando el éxodo rural que ya era de por sí considerable. Por otra, la pérdida de calidad de vida la asociamos a la merma de suelo cultivable y el deterioro del medio al poner en cultivo tierras forestales. La agricultura es de subsistencia y como tal está sometida a la supervivencia de las familias en un medio cada vez más desfavorable. Las intervenciones en este medio podrían tomar como ejemplo los patrones que se han aplicado en el entorno rural español en el pasado, cuyo deterioro siguió pautas similares en un período de tiempo más largo.

Li tho bio chemistratrigraphy in Mina Verdum group Nico Perez terrain-Uruguay

International Nuclear Information System (INIS)

Gaucher, C.; Martinez, G.; Cernuschi, F.; Chiglino, L.; Sial, A.; Poire, D.

2007-01-01

The occurrence of volcanic and pyroclastic rocks in the Mina Verdun Group is reported here. The unit represents a marine volcanosedimentary succession, made up from base to top of the following formations: Cerro de las Viboras Formation (metarhyolites), Don Mario Formation (pelites, sandstones), La Toma Formation (marls), El Calabozo Formation (stromatolitic limestones with Conophyton), Gibraltar Formation (mainly dolostones, subordinate marls and limestones) and Nueva Carrara Formation (acid lapilli-tuffs acidos and dolomitic metamarls). Three outcrop areas are known, located between Minas and Pan de Azucar, namely: Mina Verdun (stratotype), Burgueno Quarry and Paso del Molino (Arroyo Pan de Azucar). Diamictites and orthoconglomerates of the Las Ventanas Formation overly with erosional and angular unconformity the Mina Verdun Group. The age of the succession is pre-Ediacaran, and bracketed between the late Mesoproterozoic and Tonian (1300-850 Ma) according to the chemostratigraphic data and the stromatolite assemblages. Carbonates of the Mina Verdun Group show a ?13C curve at its stratotype, which is characterized by a basal negative excursion to -3.3 PDB, followed by moderately positive values in the rest of the section, representing a plateau around +2 ? PDB. In the southern part of its outcrop area, limestones of the Mina Verdun Group show more negative de ?13C and ?18O values, as well as a maniphest decoloration. These characteristics are the result of contact-metamorphism of nearby granitic plutons in that area. (author)

Simulated anthropogenic CO2 storage and acidification of the Mediterranean Sea

Directory of Open Access Journals (Sweden)

J. Palmiéri

2015-02-01

Full Text Available Constraints on the Mediterranean Sea's storage of anthropogenic CO2 are limited, coming only from data-based approaches that disagree by more than a factor of two. Here we simulate this marginal sea's anthropogenic carbon storage by applying a perturbation approach in a high-resolution regional model. Our model simulates that, between 1800 and 2001, basin-wide CO2 storage by the Mediterranean Sea has increased by 1.0 Pg C, a lower limit based on the model's weak deep-water ventilation, as revealed by evaluation with CFC-12. Furthermore, by testing a data-based approach (transit time distribution in our model, comparing simulated anthropogenic CO2 to values computed from simulated CFC-12 and physical variables, we conclude that the associated basin-wide storage of 1.7 Pg, published previously, must be an upper bound. Out of the total simulated storage of 1.0 Pg C, 75% comes from the air–sea flux into the Mediterranean Sea and 25% comes from net transport from the Atlantic across the Strait of Gibraltar. Sensitivity tests indicate that the Mediterranean Sea's higher total alkalinity, relative to the global-ocean mean, enhances the Mediterranean's total inventory of anthropogenic carbon by 10%. Yet the corresponding average anthropogenic change in surface pH does not differ significantly from the global-ocean average, despite higher total alkalinity. In Mediterranean deep waters, the pH change is estimated to be between −0.005 and −0.06 pH units.

An uncommon or just an ecologically demanding species? Finding of aggregations of the brittle-star Ophiothrix maculata on the Northwest African slope

Science.gov (United States)

Calero, Belén; Ramos, Ana; Ramil, Fran

2018-01-01

Ophiuroidea constitutes the largest class of the phylum Echinodermata. It includes families with suspension-feeder behaviour that can be found in dense aggregations in all oceans worldwide. Ophiothrix maculata was known as a rare suspension-feeder brittle star, with only four records in the Eastern Central Atlantic dating from almost 100 years ago. During the ten multidisciplinary Spanish and Norwegian surveys carried out from 2004 to 2012 off Northwest Africa, between the Gibraltar Strait and the Sierra Leone border from 19 to 1888 m depth, we sampled 1298 stations. We gathered about one million individuals and 124 kg of brittle stars at 501 of the stations. Eight hundred and thirty-two specimens of Ophiothrix maculata were collected at six localities on the continental slope off Mauritania, Western Sahara and Guinea Bissau, at depths between 155 and 594 m. The Guinea Bissau samples represent the southernmost current record for the species. Even though Ophiothrix maculata has been previously recorded only in isolation, we discovered dense concentrations on the Mauritanian slope on the Wolof's Seamount (580 individuals) and off the Western Sahara, in a Lophelia pertusa reef (202 individuals). In this paper, we describe these findings and discuss the association of this species to hard-bottom habitats and high primary production areas, outside of the oxygen minimum zone (OMZ). We also analyse what other factors may explain the patchy distribution of O. maculata on the Northwest African slope.

Modelling seabird collision risk with off-shore wind farms

Energy Technology Data Exchange (ETDEWEB)

Mateos, Maria; Arroyo, Gonzalo Munoz; Rosario, Jose Juan Alonso del

2011-07-01

Full text: Recent concern about the adverse effects of collision mortality of avian migrants at wind farms has highlighted the need to understand bird-wind turbine interactions. Here, a stochastic collision model, based on data of seabird behaviour collected on- site, is presented, as a flexible and easy to take tool to assess the collisions probabilities of off-shore wind farms in a pre-construction phase. The collision prediction model considering the wind farm area as a risk window has been constructed as a stochastic model for avian migrants, based on Monte Carlo simulation. The model calculates the probable number of birds collided per time unit. Migration volume, wind farm dimensions, vertical and horizontal distribution of the migratory passage, flight direction and avoidance rates, between other variables, are taken into account in different steps of the model as the input variables. In order to assess the weighted importance of these factors on collision probability predictions, collision probabilities obtained from the set of scenarios resulting from the different combinations of the input variables were modelled by using Generalised Additive Models. The application of this model to a hypothetical project for erecting a wind farm at the Strait of Gibraltar showed that collision probability, and consequently mortality rates, strongly depend on the values of the avoidance rates taken into account, and the distribution of birds into the different altitude layers. These parameters should be considered as priorities to be addressed in post-construction studies. (Author)

A look at the ocean in the EC-Earth climate model

Energy Technology Data Exchange (ETDEWEB)

Sterl, Andreas; Bintanja, Richard; Severijns, Camiel [Royal Netherlands Meteorological Institute (KNMI), P.O. Box 201, De Bilt (Netherlands); Brodeau, Laurent [Stockholm University, Department of Meteorology, Stockholm (Sweden); Gleeson, Emily; Semmler, Tido [Met Eireann, Dublin (Ireland); Koenigk, Torben; Wyser, Klaus [Swedish Meteorological and Hydrological Institute (SMHI), Norrkoeping (Sweden); Schmith, Torben; Yang, Shuting [Danish Meteorological Institute (DMI), Copenhagen (Denmark)

2012-12-15

EC-Earth is a newly developed global climate system model. Its core components are the Integrated Forecast System (IFS) of the European Centre for Medium Range Weather Forecasts (ECMWF) as the atmosphere component and the Nucleus for European Modelling of the Ocean (NEMO) developed by Institute Pierre Simon Laplace (IPSL) as the ocean component. Both components are used with a horizontal resolution of roughly one degree. In this paper we describe the performance of NEMO in the coupled system by comparing model output with ocean observations. We concentrate on the surface ocean and mass transports. It appears that in general the model has a cold and fresh bias, but a much too warm Southern Ocean. While sea ice concentration and extent have realistic values, the ice tends to be too thick along the Siberian coast. Transports through important straits have realistic values, but generally are at the lower end of the range of observational estimates. Exceptions are very narrow straits (Gibraltar, Bering) which are too wide due to the limited resolution. Consequently the modelled transports through them are too high. The strength of the Atlantic meridional overturning circulation is also at the lower end of observational estimates. The interannual variability of key variables and correlations between them are realistic in size and pattern. This is especially true for the variability of surface temperature in the tropical Pacific (El Nino). Overall the ocean component of EC-Earth performs well and helps making EC-Earth a reliable climate model. (orig.)

Cryptic diversity in Mediterranean gastropods of the genus Aplus (Neogastropoda: Buccinidae

Directory of Open Access Journals (Sweden)

Chrifa Aissaoui

2016-11-01

Full Text Available Northeastern Atlantic and Mediterranean gastropods previously ascribed to the buccinid genus Pollia Gray, 1837 are more correctly classified in the genus Aplus de Gregorio, 1885. Using an integrative taxonomy approach combining molecular, morphological and geographic data, we revisit the limits of the extant species in the area, and propose a molecular phylogenetic hypothesis based on 66 specimens from various localities in the Mediterranean Sea, including type localities of some nominal taxa. We used a preliminary morphological inspection, followed by a DNA-barcoding approach to propose species hypotheses, subsequently consolidated using additional data (phylogenetic, geographic and refined morphological data. Seven species hypotheses were eventually retained within our molecularly assayed samples, versus three classical morphologically recognized species. Among these, three correspond to Aplus dorbignyi (Payreaudeau, 1826 with its hitherto unrecognized geographical cognates A. gaillardoti (Puton, 1856 (eastern Mediterranean and Aplus nodulosus (Bivona Ant., 1832 (Sicily; two closely related, yet considerably divergent, lineages are treated as a single species under Aplus scaber (Locard, 1892; the classically admitted Aplus scacchianus (Philippi, 1844 is confirmed by molecular evidence; Mediterranean populations attributable to Aplus assimilis (Reeve, 1846 may represent either cryptic native populations or an ongoing invasion of the Mediterranean by what was hitherto considered to be a West African species; finally, specimens from the Strait of Gibraltar may represent an undescribed species, but we conservatively refrain from formally introducing it pending the analysis of more material, and it is compared with the similar Aplus campisii (Ardovini, 2014, recently described from Sicily and not assayed molecularly, and Aplus scaber.

Morphodynamic characterization of the Spanish beaches of the Gulf of Cadiz

Energy Technology Data Exchange (ETDEWEB)

Benavente, J.; Gracia, F. J.; Rio, L. del; Anfuso, G.; Rodriguez-Ramirez, A.

2015-07-01

During the1980s several attempts were made to classify beaches according to their morphodynamic behav- iour. Published papers proposed classifications based mainly on wave incident energy and beach character- istics, such as foreshore slopes and sediment settling velocities. In the 1990s more complex classifications appeared, where the effect of tides on wave action was included, highlighting their relevance to the determi- nation of the morphodynamic state of the beach. In this paper we present a beach monitoring programme, in which more than 30 beaches located along the Spanish shores of the Gulf of Cadiz and the Strait of Gibraltar were surveyed for four years (2000-2004). The long study period allowed the monitoring of beach morphologies related both to fair weather (summer) and storm (winter) conditions. The coastal setting in the study area provided the opportunity for covering a wide range of tidal conditions, from high mesotidal (MSTR ca. 4 m) to microtidal (MSTR around 1 m). Furthermore, the dimensions of the study area permitted the mon- itoring of beaches linked to different boundary conditions, thus including both attached and detached beach- es located at varying distances from main sediment sources, and influenced by different wave regimes. The analysis of the beach morphologies related to such contrasting conditions allowed the identification of the real significance of the tidal effect on beach profile morphology and hence on beach morphodynamics. Finally, we conclude that the effect of tides on wave action is the main factor determining beach morphody- namic behaviour. (Author)

New Pn and Sn tomographic images of the uppermost mantle beneath the Mediterranean region

Science.gov (United States)

Gil, A.; Díaz, J.; Gallart, J.

2012-04-01

We present here new images of the seismic velocity and anisotropy variations in the uppermost mantle beneath the Mediterranean region, compiled from inversion of Pn and Sn phases. The method of Hearn (1996) has been applied to Pn and Sn lectures from the catalogs of the International Seismological Center and the Spanish Instituto Geografico Nacional. A total of 1,172,293 Pn arrivals coming from 16,527 earthquakes recorded at 1,657 stations with epicentral distances between 220 km and 1400 km have been retained (331,567 arrivals from 15,487events at 961 stations for Sn). Our results, grossly consistent with available 3D tomography images, show significant features well correlated with surface geology. The Pn velocities are high (>8.2 km/s) beneath major sedimentary basins (western Alboran Sea, Valencia Trough, Adriatic Sea, Aquitaine, Guadalquivir, Rharb, Aquitaine and Po basins), and low (Islands, probably related to a thermal anomaly associated to the westward displacement of the Alboran block along the Emile Baudot escarpment 16 Ma ago. The Pn anisotropic image shows consistent orientations sub-parallel to major orogenic structures, such as Betics, Apennines, Calabrian Arc and Alps. The station delays beneath Betic and Rif ranges are strongly negative, suggesting the presence of crustal thickening all along the Gibraltar Arc. However, only the Betics have a very strong low-velocity anomaly and a pronounced anisotropy pattern. The Sn tomographic image correlates well with the Pn image, even if some relevant differences can be observed beneath particular regions.

Rapid assessment of non-indigenous species in the era of the eDNA barcoding: A Mediterranean case study

Science.gov (United States)

Ardura, Alba; Planes, Serge

2017-03-01

With only a narrow opening through the Gibraltar and Suez Canals, the Mediterranean Sea is one of the largest semi-enclosed seas. The marine flora and fauna are some of the richest in the world, relative to its size, particularly in the coastal habitats, which are also characterized by numerous endemic species although the introduction of non-indigenous species threatens its rich and unique biodiversity. Following the opening of the Suez Canal, and in combination with shipping and aquaculture activities, non-indigenous species (NIS) introduction has had measurable impacts on the Mediterranean. Lagoon ecosystems along the French coastline, with approx. 100 NIS identified, are considered hot-spot areas for these species. Rapid assessment sampling for sessile benthic species together with DNA barcoding is a rapid, easy and cheap method to detect non-indigenous species. Two nearby and different ecosystems were sampled for invertebrate species: Saint-Nazaire lagoon, a Special Protection Area within the Natura 2000 Network and Canet port, a marina in a small village. The DNA barcoding tool for species identification was used for confirming the taxonomy. This showed that, despite the Saint-Nazaire Lagoon classification within the Natura 2000 network, it is already contaminated with a single NIS that was found in high densities and is clearly beginning to dominate the system. It is proposed that a rapid assessment of the sampled environment and the DNA barcode approach are efficient and can provide sufficient information on the new target species to be used in conservation planning and ongoing management efforts.

A Mediterranean nocturnal heavy rainfall and tornadic event. Part I: Overview, damage survey and radar analysis

Science.gov (United States)

Bech, Joan; Pineda, Nicolau; Rigo, Tomeu; Aran, Montserrat; Amaro, Jéssica; Gayà, Miquel; Arús, Joan; Montanyà, Joan; der Velde, Oscar van

2011-06-01

This study presents an analysis of a severe weather case that took place during the early morning of the 2nd of November 2008, when intense convective activity associated with a rapidly evolving low pressure system affected the southern coast of Catalonia (NE Spain). The synoptic framework was dominated by an upper level trough and an associated cold front extending from Gibraltar along the Mediterranean coast of the Iberian Peninsula to SE France, which moved north-eastward. South easterly winds in the north of the Balearic Islands and the coast of Catalonia favoured high values of 0-3 km storm relative helicity which combined with moderate MLCAPE values and high shear favoured the conditions for organized convection. A number of multicell storms and others exhibiting supercell features, as indicated by Doppler radar observations, clustered later in a mesoscale convective system, and moved north-eastwards across Catalonia. They produced ground-level strong damaging wind gusts, an F2 tornado, hail and heavy rainfall. Total lightning activity (intra-cloud and cloud to ground flashes) was also relevant, exhibiting several classical features such as a sudden increased rate before ground level severe damage, as discussed in a companion study. Remarkable surface observations of this event include 24 h precipitation accumulations exceeding 100 mm in four different observatories and 30 minute rainfall amounts up to 40 mm which caused local flash floods. As the convective system evolved northward later that day it also affected SE France causing large hail, ground level damaging wind gusts and heavy rainfall.

Insights on the evolution of mid-ocean basins: the Atlantis Basin of southern Azores

Science.gov (United States)

Alves, T.; Bouriak, S.; Volkonskaya, A.; Monteiro, J.; Ivanov, M.

2003-04-01

Single-channel seismic reflection and sidescan (OKEAN) data acquired in an unstudied region of the North Atlantic give important insights on the evolution of mid-ocean basins. Located on the eastern flank of the Mid-Atlantic Ridge, south of the Azores Islands, the study area contains more than 1,000 ms two-way travel-time of sediments with a similar seismic stratigraphy to that of ODP sites 950-952 in the Madeira Abyssal Plain. Processed thickness values correspond to a maximum thickness of about 1450 m and an average thickness of more than 500 m based on velocity data from ODP sites 950-952. The structure of the surveyed area and its location in relation to the Madeira Abyssal Plain and Mid-Atlantic Ridge indicate the existence, south of Azores, of two distinct sedimentary basins separated by major structural lineaments (Azores-Gibraltar and Atlantis Fracture Zones) and by seamount chains (Cruiser-Great Meteor Chain, Plato-Atlantis Chain). The basement of the sedimentary basins is irregular, showing multiple dome-shaped volcanic structures identical to those in the Norwegian-Greenland Sea and Madeira Abyssal Plain. However, half-graben/graben basement blocks predominate east of 30ºW underneath a moderately deformed overburden. The complex structure observed most likely reflects changes in the direction and velocity of ocean spreading plus variations in the regional thermal gradients induced by local hot spots. In parallel, some of the sub-surface structures identified next to basin-bounding Fracture Zones may have resulted from transtensional and transpressional tectonism.

As main meal for sperm whales: plastics debris.

Science.gov (United States)

de Stephanis, Renaud; Giménez, Joan; Carpinelli, Eva; Gutierrez-Exposito, Carlos; Cañadas, Ana

2013-04-15

Marine debris has been found in marine animals since the early 20th century, but little is known about the impacts of the ingestion of debris in large marine mammals. In this study we describe a case of mortality of a sperm whale related to the ingestion of large amounts of marine debris in the Mediterranean Sea (4th published case worldwide to our knowledge), and discuss it within the context of the spatial distribution of the species and the presence of anthropogenic activities in the area that could be the source of the plastic debris found inside the sperm whale. The spatial distribution modelled for the species in the region shows that these animals can be seen in two distinct areas: near the waters of Almería, Granada and Murcia and in waters near the Strait of Gibraltar. The results shows how these animals feed in waters near an area completely flooded by the greenhouse industry, making them vulnerable to its waste products if adequate treatment of this industry's debris is not in place. Most types of these plastic materials have been found in the individual examined and cause of death was presumed to be gastric rupture following impaction with debris, which added to a previous problem of starvation. The problem of plastics arising from greenhouse agriculture should have a relevant section in the conservation plans and should be a recommendation from ACCOBAMS due to these plastics' and sperm whales' high mobility in the Mediterranean Sea. Copyright © 2013 Elsevier Ltd. All rights reserved.

Tracers confirm downward mixing of Tyrrhenian Sea upper waters associated with the Eastern Mediterranean Transient

Directory of Open Access Journals (Sweden)

W. Roether

2011-01-01

Full Text Available Observations of tritium and ³He in the Tyrrhenian Sea, 1987–2009, confirm the enhanced vertical mixing of intermediate waters into the deep waters that has been noted and associated with the Eastern Mediterranean Transient in previous studies. Our evidence for the mixing rests on increasing tracer concentrations in the Tyrrhenian deep waters, accompanied by decreases in the upper waters, which are supplied from the Eastern Mediterranean. The downward transfer is particularly evident between 1987 and 1997. Later on, information partly rests on increasing tritium-³He ages; here we correct the observed ³He for contributions released from the ocean floor. The Tyrrhenian tracer distributions are fully compatible with data upstream of the Sicily Strait and in the Western Mediterranean. The tracer data show that mixing reached to the bottom and confirm a cyclonic nature of the deep water circulation in the Tyrrhenian. They furthermore indicate that horizontal homogenization of the deep waters occurs on a time scale of roughly 5 years. Various features point to a reduced impact of Western Mediterranean Deep Water (WMDW in the Tyrrhenian during the enhanced-mixing period. This is an important finding because it implies less upward mixing of WMDW, which has been named a major process to enable the WMDW to leave the Mediterranean via the Gibraltar Strait. On the other hand, the TDW outflow for several years represented a major influx of enhanced salinity and density waters into the deep-water range of the Western Mediterranean.

Circulation and oxygen cycling in the Mediterranean Sea: Sensitivity to future climate change

Science.gov (United States)

Powley, Helen R.; Krom, Michael D.; Van Cappellen, Philippe

2016-11-01

Climate change is expected to increase temperatures and decrease precipitation in the Mediterranean Sea (MS) basin, causing substantial changes in the thermohaline circulation (THC) of both the Western Mediterranean Sea (WMS) and Eastern Mediterranean Sea (EMS). The exact nature of future circulation changes remains highly uncertain, however, with forecasts varying from a weakening to a strengthening of the THC. Here we assess the sensitivity of dissolved oxygen (O2) distributions in the WMS and EMS to THC changes using a mass balance model, which represents the exchanges of O2 between surface, intermediate, and deep water reservoirs, and through the Straits of Sicily and Gibraltar. Perturbations spanning the ranges in O2 solubility, aerobic respiration kinetics, and THC changes projected for the year 2100 are imposed to the O2 model. In all scenarios tested, the entire MS remains fully oxygenated after 100 years; depending on the THC regime, average deep water O2 concentrations fall in the ranges 151-205 and 160-219 µM in the WMS and EMS, respectively. On longer timescales (>1000 years), the scenario with the largest (>74%) decline in deep water formation rate leads to deep water hypoxia in the EMS but, even then, the WMS deep water remains oxygenated. In addition, a weakening of THC may result in a negative feedback on O2 consumption as supply of labile dissolved organic carbon to deep water decreases. Thus, it appears unlikely that climate-driven changes in THC will cause severe O2 depletion of the deep water masses of the MS in the foreseeable future.

Caracterización geoquímica de la esméctica en varias formaciones arcillosas de los flyschs del Campo de Gibraltar (Cádiz, España

Directory of Open Access Journals (Sweden)

Esteras Martín, M.

1993-12-01

Full Text Available The «Jimena clays», «basal series of Aljibe» and «blocky clays» formations are compared from the mineralogical and geochemical analysis. The mineralogy of clays is very similar in all the sequences analyzed and consists of quartz, smectite, illite and kaolinite. Smaller amounts of feldspar, gypsum and chlorite are locally presento In the 2-20 μm and Se comparan desde un punto de vista mineralógico y geoquímico las formaciones definidas como «arcillas de Jimena», «sucesión basal del Aljibe» y «arcillas con bloques». Su mineralogía resulta muy similar: cuarzo, esmectita, ilita y caolinita, junto con pequeñas proporciones de feldespato, yeso y clorita. En las fracciones 2-20 µm y < 2 μm la esmectita es el mineral más abundante. La semejanza mineralógica se pone también de manifiesto en la composición química de estos materiales. La composición de las esmectitas corresponde a montmorillonita y sugiere un origen detrítico para las mismas. El contenido en diversos elementos traza indica que estos materiales son el producto de la meteorización de rocas magmáticas ácidas junto con rocas sedimentarias antiguas. La homogeneidad de las secuencias analizadas indica, asimismo, una homología de todas las formaciones y una gran uniformidad en los aportes durante el intervalo Cretácico-Eoceno, época a la que se atribuye su depósito.

IEOOS: the Spanish Institute of Oceanography Observing System

Science.gov (United States)

Tel, E.; Balbin, R.; Cabanas, J. M.; Garcia, M. J.; Garcia-Martinez, M. C.; Gonzalez-Pola, C.; Lavin, A.; Lopez-Jurado, J. L.; Rodriguez, C.; Ruiz-Villarreal, M.; Sanchez-Leal, R. F.; Vargas-Yanez, M.; Velez-Belchi, P.

2015-10-01

Since its foundation, 100 years ago, the Spanish Institute of Oceanography (IEO) has been observing and measuring the ocean characteristics. Here is a summary of the initiatives of the IEO in the field of the operational oceanography (OO). Some systems like the tide gauges network has been working for more than 70 years. The IEO standard sections began at different moments depending on the local projects, and nowadays there are more than 180 coastal stations and deep-sea ones that are systematically sampled, obtaining physical and biochemical measurements. At this moment, the IEO Observing System (IEOOS) includes 6 permanent moorings equipped with currentmeters, an open-sea ocean-meteorological buoy offshore Santander and an SST satellital image reception station. It also supports the Spanish contribution to the ARGO international program with 47 deployed profilers, and continuous monitoring thermosalinometers, meteorological stations and ADCP onboard the IEO research vessels. The system is completed with the IEO contribution to the RAIA and Gibraltar observatories, and the development of regional prediction models. All these systematic measurements allow the IEO to give responses to ocean research activities, official agencies requirements and industrial and main society demands as navigation, resource management, risks management, recreation, etc, as well as for management development pollution-related economic activities or marine ecosystems. All these networks are linked to international initiatives, framed largely in supranational programs Earth observation sponsored by the United Nations or the European Union. The synchronic observation system permits following spatio-temporal description of some events, as new deep water formation in the Mediterranean Sea and the injection of heat to intermediate waters in the Bay of Biscay after some colder northern storms in winter 2005.

Management Implications for the Most Attractive Scenic Sites along the Andalusia Coast (SW Spain

Directory of Open Access Journals (Sweden)

Alexis Mooser

2018-04-01

Full Text Available A coastal scenery assessment was carried out at 50 sites along the 910 km long Andalusia coast (SW Spain using a checklist of 26 natural and human parameters, parameter weighting matrices, and fuzzy logic. A scenic classification was utilised that can rate sites as Class I (natural areas of great scenic beauty to Class V (urbanised areas of poor scenic interest, but, for this study, only natural sites of great scenic value were investigated; 41 sites were included in Class I, 9 in Class II and, apart from four, all of the sites were under some feature of protection—managed by the Andalusia Environmental Agency (RENPA, in Spanish. Sites belong to the Natural Park Cabo de Gata-Nijar (24% of sites, the Natural Park of Gibraltar Strait (18%, the Natural Place Acantilado de Maro-Cerro Gordo (12%, and the Natural and National parks of Doñana (8%. Results obtained by means of scenic evaluation constitute a sound scientific basis for any envisaged management plan for investigated coastal areas preservation/conservation and responsible future developments, especially for natural protected areas, which represent the most attractive coastal tourist destinations. With respect to natural parameters, excellent scenic values appeared to be linked to the geological setting and the presence of mountainous landscapes related to the Betic Chain. Human parameters usually show good scores because null or extremely reduced human impacts are recorded, but, at places, conflicts arose between conservation and recreational activities because visitors are often interested in beach activities more so than ecotourism. Low scores of human parameters were often related to litter presence or the unsuitable emplacement of utilities, such as informative panels, litter bins, etc.

Interhemispheric teleconnections: Late Pliocene change in Mediterranean outflow water linked to changes in Indonesian Through-Flow and Atlantic Meridional Overturning Circulation, a review and update

Science.gov (United States)

Sarnthein, Michael; Grunert, Patrick; Khélifi, Nabil; Frank, Martin; Nürnberg, Dirk

2018-03-01

The ultimate, possibly geodynamic control and potential impact of changes in circulation activity and salt discharge of Mediterranean outflow waters (MOW) on Atlantic meridional overturning circulation have formed long-standing objectives in paleoceanography. Late Pliocene changes in the distal advection of MOW were reconstructed on orbital timescales for northeast Atlantic DSDP/ODP sites 548 and 982 off Brittany and on Rockall Plateau, supplemented by a proximal record from Site U1389 west off Gibraltar, and compared to Western Mediterranean surface and deep-water records of Alboran Sea Site 978. From 3.43 to 3.3 Ma, MOW temperatures and salinities form a prominent rise by 2-4 °C and 3 psu, induced by a preceding and coeval rise in sea surface and deep-water salinity and increased summer aridity in the Mediterranean Sea. We speculate that these changes triggered an increased MOW flow and were ultimately induced by a persistent 2.5 °C cooling of Indonesian Through-Flow waters. The temperature drop resulted from the northward drift of Australia that crossed a threshold value near 3.6-3.3 Ma and led to a large-scale cooling of the eastern subtropical Indian Ocean and in turn, to a reduction of African monsoon rains. Vice versa, we show that the distinct rise in Mediterranean salt export after 3.4 Ma induced a unique long-term rise in the formation of Upper North Atlantic Deep Water, that followed with a phase lag of 100 ky. In summary, we present evidence for an interhemispheric teleconnection of processes in the Indonesian Gateways, the Mediterranean and Labrador Seas, jointly affecting Pliocene climate.

What can otolith shape analysis tell us about population structure of the European sardine, Sardina pilchardus, from Atlantic and Mediterranean waters?

Science.gov (United States)

Jemaa, Sharif; Bacha, Mahmoud; Khalaf, Gaby; Dessailly, David; Rabhi, Khalef; Amara, Rachid

2015-02-01

The European sardine, Sardina pilchardus, exhibits a complex population structure, which has produced conflicting results in previous genetic studies. Despite its importance in the fisheries industry, stock delineation for management and conservation purposes is still a matter of debate throughout the distribution range of the species. This study examines whether otolith shapes are more efficient than genetic markers to detect population structure in pelagic species with large population sizes. Sardines were analyzed from 15 sampling localities in the Northeast Atlantic and Mediterranean Sea covering almost the whole distribution range of the species. A combination of otolith shape indices and elliptic Fourier descriptors was investigated by multivariate statistical procedures. Within the studied area, three distinct groups were identified with an overall correct classification of 77%. Group A: northern Mediterranean Sea and Gulf of Gabès; group B: Atlantic Morocco-south Alboran-Algero-provençal coasts; and group C: European Atlantic coast. The Almeria-Oran front and the Gibraltar strait are not an efficient barrier for sardine population separation as there seems to be exchanges between populations of the south-western Mediterranean Sea and those of the Moroccan Atlantic Ocean coast or Gulf of Cadiz. The results are discussed in relation to environmental conditions, oceanographic features, and physical barriers to dispersal in the study area, and compared with those obtained by previous genetic, morphometric, and meristic data. For pelagic species with high gene flow, present results highlighted the need to take into account the identification of phenotypic stocks to ensure sustainable fishery benefits and efficient conservation as they may have unique demographic properties and responses to exploitation.

Topographic control on the nascent Mediterranean outflow

Science.gov (United States)

Gasser, M.; Pelegrí, J. L.; Nash, J. D.; Peters, H.; García-Lafuente, J.

2011-12-01

Data collected during a 12-day cruise in July 2009 served to examine the structure of the nascent Mediterranean Outflow Water (MOW) immediately west of the Espartel Sill, the westernmost sill in the Strait of Gibraltar. The MOW is characterized by high salinities (>37.0 and reaching 38.3) and high velocities (exceeding 1 m s-1 at 100 m above the seafloor), and follows a submerged valley along a 30 km stretch, the natural western extension of the strait. It is approx. 150 m thick and 10 km wide, and experiences a substantial drop from 420 to 530 m over a distance of some 3 km between two relatively flat regions. Measurements indicate that the nascent MOW behaves as a gravity current with nearly maximal traveling speed; if this condition is maintained, then the maximum MOW velocity would decrease slowly with distance from the Espartel Sill, remaining significantly high until the gravity current excess density is only a small fraction of its original value. The sharp pycnocline between the Mediterranean and the overlying North Atlantic Central waters is dynamically unstable, particularly where the flow interacts with the 100 m decrease in bottom depth. Here, subcritical gradient Richardson numbers coincide with the development of large interfacial undulations and billows. The very energetic downslope flow is likely responsible for the development of a narrow V-shaped channel downstream of the seafloor drop along the axis of the submerged valley, this probably being the very first erosional scour produced by the nascent MOW. The coincidence of subcritical gradient Richardson numbers with relatively high turbidity values above the channel flanks suggests it may be undergoing upstream erosion.

Tectonic evolution of the Sicilian Maghrebian Chain inferred from stratigraphic and petrographic evidences of Lower Cretaceous and Oligocene flysch

Directory of Open Access Journals (Sweden)

Puglisi Diego

2014-08-01

Full Text Available The occurrence of a Lower Cretaceous flysch group, cropping out from the Gibraltar Arc to the Balkans with a very similar structural setting and sedimentary provenance always linked to the dismantling of internal areas, suggests the existence of only one sedimentary basin (Alpine Tethys s.s., subdivided into many other minor oceanic areas. The Maghrebian Basin, mainly developed on thinned continental crust, was probably located in the westernmost sector of the Alpine Tethys. Cretaceous re-organization of the plates triggered one (or more tectonic phases, well recorded in almost all the sectors of the Alpine Tethys. However, the Maghrebian Basin seems to have been deformed by Late- or post-Cretaceous tectonics, connected with a “meso-Alpine” phase (pre-Oligocene, already hypothesized since the beginning of the nineties. Field geological evidence and recent biostratigraphic data also support this important meso- Alpine tectonic phase in the Sicilian segment of the Maghrebian Chain, indicated by the deformations of a Lower Cretaceous flysch sealed by Lower Oligocene turbidite deposits. This tectonic development is emphasized here because it was probably connected with the onset of rifting in the southern paleomargin of the European plate, the detaching of the so-called AlKaPeCa block (Auct.; i.e. Alboran + Kabylian + Calabria and Peloritani terranes and its fragmentation into several microplates. The subsequent early Oligocene drifting of these microplates led to the progressive closure of the Maghrebian Basin and the opening of new back-arc oceanic basins, strongly controlled by extensional processes, in the western Mediterranean (i.e. Gulf of Lion, Valencia Trough, Provençal Basin and Alboran Sea.

The influence of the waterjet propulsion system on the ships' energy consumption and emissions inventories.

Science.gov (United States)

Durán-Grados, Vanesa; Mejías, Javier; Musina, Liliya; Moreno-Gutiérrez, Juan

2018-08-01

In this study we consider the problems associated with calculating ships' energy and emission inventories. Various related uncertainties are described in many similar studies published in the last decade, and applying to Europe, the USA and Canada. However, none of them have taken into account the performance of ships' propulsion systems. On the one hand, when a ship uses its propellers, there is no unanimous agreement on the equations used to calculate the main engines load factor and, on the other, the performance of waterjet propulsion systems (for which this variable depends on the speed of the ship) has not been taken into account in any previous studies. This paper proposes that the efficiency of the propulsion system should be included as a new parameter in the equation that defines the actual power delivered by a ship's main engines, as applied to calculate energy consumption and emissions in maritime transport. To highlight the influence of the propulsion system on calculated energy consumption and emissions, the bottom-up method has been applied using data from eight fast ferries operating across the Strait of Gibraltar over the course of one year. This study shows that the uncertainty about the efficiency of the propulsion system should be added as one more uncertainty in the energy and emission inventories for maritime transport as currently prepared. After comparing four methods for this calculation, the authors propose a new method for eight cases. For the calculation of the Main Engine's fuel oil consumption, differences up to 22% between some methods were obtained at low loads. Copyright © 2018 Elsevier B.V. All rights reserved.

Low planktic foraminiferal diversity and abundance observed in a spring 2013 west-east Mediterranean Sea plankton tow transect

Science.gov (United States)

Mallo, Miguel; Ziveri, Patrizia; Mortyn, P. Graham; Schiebel, Ralf; Grelaud, Michael

2017-05-01

Planktic foraminifera were collected with 150 µm BONGO nets from the upper 200 m water depth at 20 stations across the Mediterranean Sea between 2 May and 2 June 2013. The main aim is to characterize the species distribution and test the covariance between foraminiferal area density (ρA) and seawater carbonate chemistry in a biogeochemical gradient including ultraoligotrophic conditions. Average foraminifera abundances are 1.42 ± 1.43 ind. 10 m-3 (ranging from 0.11 to 5.20 ind. 10 m-3), including 12 morphospecies. Large differences in species assemblages and total abundances are observed between the different Mediterranean sub-basins, with an overall dominance of spinose, symbiont-bearing species indicating oligotrophic conditions. The highest values in absolute abundance are found in the Strait of Gibraltar and the Alboran Sea. The western basin is dominated by Globorotalia inflata and Globigerina bulloides at slightly lower standing stocks than in the eastern basin. In contrast, the planktic foraminiferal assemblage in the warmer, saltier, and more nutrient-limited eastern basin is dominated by Globigerinoides ruber (white). These new results, when combined with previous findings, suggest that temperature-induced surface water stratification and food availability are the main factors controlling foraminiferal distribution. In the oligotrophic and highly alkaline and supersaturated with respect to calcite and aragonite Mediterranean surface water, standing stocks and ρA of G. ruber (white) and G. bulloides are affected by both food availability and seawater carbonate chemistry. Rapid warming increased surface ocean stratification impacting food availability and changes in trophic conditions could be the causes of reduced foraminiferal abundance, diversity, and species-specific changes in planktic foraminiferal calcification.

Impact of restriction of the Atlantic-Mediterranean gateway on the Mediterranean Outflow Water and eastern Atlantic circulation during the Messinian

Science.gov (United States)

PéRez-Asensio, J. N.; Aguirre, J.; Schmiedl, G.; Civis, J.

2012-09-01

Messinian foraminiferal stable oxygen and carbon isotopes of the Montemayor-1 core (Guadalquivir Basin, SW Spain) have been investigated. This record is exceptional to study the Mediterranean Outflow Water (MOW) impact on the Atlantic meridional overturning circulation (AMOC) and global climate during the Messinian because the core is near the Guadalhorce Corridor, the last Betic gateway to be closed during the early Messinian. Our results allow dating accurately its closure at 6.18 Ma. Constant benthicδ18O values, high difference between benthic and planktonic δ18O, and low sedimentation rates before 6.18 Ma indicate the presence of a two-layer water column, with bottom winnowing due to an enhanced Mediterranean outflow current. The enhanced contribution of dense MOW to the North Atlantic Ocean likely fostered the formation of North Atlantic Deep Water (NADW). After 6.18 Ma, benthicδ18O values parallel that of the global glacioeustatic curve, the difference between benthic and planktonic δ18O is low, and sedimentation rates considerably increased. This indicates a good vertical mixing of the water column, interruption of the MOW, and a dominant glacioeustatic control on the isotopic signatures. According to the role of MOW in the modern Atlantic thermohaline circulation, the reduction of the MOW after the closure of the Guadalhorce Corridor might have resulted in a decreased NADW formation rate between 6.0 and 5.5 Ma weakening the AMOC and promoting northern hemisphere cooling. After the Gibraltar Strait opening, the restoration of the MOW and related salt export from the Mediterranean could have promoted an enhanced NADW formation.

Subduction initiation, recycling of Alboran lower crust, and intracrustal emplacement of subcontinental lithospheric mantle in the Westernmost Mediterranean

Science.gov (United States)

Varas-Reus, María Isabel; Garrido, Carlos J.; Bosch, Delphine; Marchesi, Claudio; Hidas, Károly; Booth-Rea, Guillermo; Acosta-Vigil, Antonio

2015-04-01

Unraveling the tectonic settings and processes involved in the annihilation of subcontinental mantle lithosphere is of paramount importance for our understanding of the endurance of continents through Earth history. Unlike ophiolites -- their oceanic mantle lithosphere counterparts -- the mechanisms of emplacement of the subcontinental mantle lithosphere in orogens is still poorly known. The emplacement of subcontinental lithospheric mantle peridotites is often attributed to extension in rifted passive margins or continental backarc basins, accretionary processes in subduction zones, or some combination of these processes. One of the most prominent features of the westernmost Mediterranean Alpine orogenic arcs is the presence of the largest outcrops worldwide of diamond facies, subcontinental mantle peridotite massifs; unveiling the mechanisms of emplacement of these massifs may provide important clues on processes involved in the destruction of continents. The western Mediterranean underwent a complex Alpine evolution of subduction initiation, slab fragmentation, and rollback within a context of slow convergence of Africa and Europe In the westernmost Mediterranean, the alpine orogeny ends in the Gibraltar tight arc, which is bounded by the Betic, Rif and Tell belts that surround the Alboran and Algero-Balearic basins. The internal units of these belts are mostly constituted of an allochthonous lithospheric domain that collided and overthrusted Mesozoic and Tertiary sedimentary rocks of the Mesozoic-Paleogene, South Iberian and Maghrebian rifted continental paleomargins. Subcontinental lithospheric peridotite massifs are intercalated between polymetamorphic internal units of the Betic (Ronda, Ojen and Carratraca massifs), Rif (Beni Bousera), and Tell belts. In the Betic chain, the internal zones of the allochthonous Alboran domain include, from bottom to top, polymetamorphic rock of the Alpujarride and Malaguide complexes. The Ronda peridotite massif -- the

Análisis epidemiológico de la mortalidad por causas en la Bahía de Algeciras (2001-2005 Epidemiological analysis of mortality by causes in Bahía de Algeciras, Spain (2001-2005

Directory of Open Access Journals (Sweden)

Concepción Cruz Rojo

2009-10-01

Full Text Available Objetivos: Analizar la mortalidad general y prematura por causas de los habitantes de la Bahía de Algeciras, un área particularmente expuesta a la contaminación atmosférica. Métodos: Se comparan las tasas ajustadas por edad y las tasas de años potenciales de vida perdidos de 1 a 70 años, por sexo y por causas, del área estudiada (años 2001 a 2005, con el resto de Andalucía (años 2001 a 2005 y el conjunto de España (año 2003 mediante la razón de las tasas (riesgo relativo y su intervalo de confianza del 95% (IC95%, y las diferencias de las tasas (riesgo atribuible. Resultados: Se encuentra un exceso de mortalidad general y prematura estadísticamente significativo en los hombres y las mujeres de la Bahía de Algeciras, una zona próxima al estrecho de Gibraltar que soporta unos altos niveles de contaminación atmosférica. El riesgo relativo de la mortalidad prematura en los hombres es de 1,16 (IC95%: 1,15-1,17 respecto a Andalucía y de 1,30 (IC95%: 1,29-1,32 respecto a España, y en las mujeres es de 1,17 (IC95%: 1,15-1,19 y 1,24 (IC95%: 1,22-1,26, respectivamente. De los grandes grupos de causas estudiados destaca el mayor riesgo de muerte por enfermedades infecciosas y parasitarias, respiratorias y tumores malignos. Por causas específicas, sobresalen la isquemia cardiaca y los tumores mal definidos en ambos sexos. En los hombres destaca la sobremortalidad general y prematura de los tumores de traquea, bronquio y pulmón, vejiga urinaria y cirrosis hepática. Conclusiones: Se constata un mayor riesgo de mortalidad general y prematura en los hombres y las mujeres de la Bahía de Algeciras, una zona con elevada concentración industrial y contaminación atmosférica. Se propone continuar con investigaciones específicas y plantear actuaciones concretas encaminadas a promover un desarrollo económico sostenible.Objective: To analyze general mortality and premature mortality by cause in the population of Bahía de Algeciras, an area

Strandings of cetaceans and sea turtles in the Alboran Sea and Strait of Gibraltar: a long–time glimpse of the north coast (Spain and the south coast (Morocco

Directory of Open Access Journals (Sweden)

Rojo–Nieto, E.

2011-06-01

Full Text Available A total of 13 species of cetaceans and three species of marine turtles were found in this study. Data were collected by eight independent and self-regulated stranding networks, providing information about 1,198 marine mammal (10 odontocetii, three mysticetii and one phocidae and 574 sea turtle stranding events between 1991 and 2008. Trends in the strandings were analysed in relation to species composition and abundance, and their geographic and seasonal distribution. The most abundant species recorded were the striped dolphin and the loggerhead turtle. Some of the strandings, such as the humpback whale, harbour porpoise, hooded seal and olive ridley turtle, were considered ‘rare’ because their distribution did not match the pattern of the study. When the north and south coasts in the study area were compared, pilot whales stranded more frequently in the north, while delphinid species stranded more in the south coast, and loggerhead turtles stranded more frequently in the north while leatherback turtles stranded more in south coast.

Internal variability in a 1000-yr control simulation with the coupled climate model ECHO-G - II. El Nino Southern Oscillation and North Atlantic Oscillation

Energy Technology Data Exchange (ETDEWEB)

Min, Seung-Ki; Hense, Andreas [Univ. of Bonn (Germany). Meteorological Inst.; Legutke, Stephanie [Max Planck Inst. for Meteorology, Hamburg (Germany); Kwon, Won-Tae [Meteorological Research Inst., Seoul (Korea, Republic of)

2005-08-01

A 1000-yr control simulation (CTL) performed with the atmosphere-ocean global climate model ECHO-G is analysed with regard to the El Nino Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO), the two major natural climatic variabilities, in comparison with observations and other model simulations. The ENSO-related sea surface temperature climate and its seasonal cycle in the tropical Pacific and a single Intertropical Convergence Zone in the eastern tropical Pacific are simulated reasonably, and the ENSO phase-locking to the annual cycle and the subsurface ocean behaviour related to equatorial wave dynamics are also reproduced well. The simulated amplitude of the ENSO signal is however too large and its occurrence is too regular and frequent. Also, the observed westward propagation of zonal wind stress over the equatorial Pacific is not captured by the model. Nevertheless, the ENSO-related teleconnection patterns of near-surface temperature (T2m), precipitation (PCP) and mean sea level pressure (MSLP) are reproduced realistically. The NAO index, defined as the MSLP difference between Gibraltar and Iceland, has a 'white' noise spectrum similar to that of the detrended index obtained from observed data. The correlation and regression patterns of T2m, PCP and MSLP with the NAO index are also successfully simulated. However, the model overestimates the warming over the North Pacific in the high index phase of the NAO, a feature it shares with other coupled models. This might be associated with an enhanced Atlantic/Pacific teleconnection, which is hardly seen in the observations. A detection analysis of the NAO index shows that the observed recent 4060 yr trend cannot be explained by the model's internal variability while the recent 2030 yr trend occurs with a more than 1% chance in ECHO-G CTL.

Subterranean karst environments as a global sink for atmospheric methane

Science.gov (United States)

Webster, Kevin D.; Drobniak, Agnieszka; Etiope, Giuseppe; Mastalerz, Maria; Sauer, Peter E.; Schimmelmann, Arndt

2018-03-01

The air in subterranean karst cavities is often depleted in methane (CH4) relative to the atmosphere. Karst is considered a potential sink for the atmospheric greenhouse gas CH4 because its subsurface drainage networks and solution-enlarged fractures facilitate atmospheric exchange. Karst landscapes cover about 14% of earth's continental surface, but observations of CH4 concentrations in cave air are limited to localized studies in Gibraltar, Spain, Indiana (USA), Vietnam, Australia, and by incomplete isotopic data. To test if karst is acting as a global CH4 sink, we measured the CH4 concentrations, δ13CCH4, and δ2HCH4 values of cave air from 33 caves in the USA and three caves in New Zealand. We also measured CO2 concentrations, δ13CCO2, and radon (Rn) concentrations to support CH4 data interpretation by assessing cave air residence times and mixing processes. Among these caves, 35 exhibited subatmospheric CH4 concentrations in at least one location compared to their local atmospheric backgrounds. CH4 concentrations, δ13CCH4, and δ2HCH4 values suggest that microbial methanotrophy within caves is the primary CH4 consumption mechanism. Only 5 locations from 3 caves showed elevated CH4 concentrations compared to the atmospheric background and could be ascribed to local CH4 sources from sewage and outgassing swamp water. Several associated δ13CCH4 and δ2HCH4 values point to carbonate reduction and acetate fermentation as biochemical pathways of limited methanogenesis in karst environments and suggest that these pathways occur in the environment over large spatial scales. Our data show that karst environments function as a global CH4 sink.

Deep Coherent Vortices and Their Sea Surface Expressions

Science.gov (United States)

Ienna, Federico; Bashmachnikov, Igor; Dias, Joaquim; Peliz, Alvaro

2017-04-01

Mediterranean Water eddies, known as Meddies, are an important dynamic process occurring at depths of 1000-meters in the Northeast Atlantic Ocean. Meddies occur as a direct result of the Mediterranean Outflow exiting through the Gibraltar Strait, and represent a prevalent mechanism that can be found extensively throughout the ocean. Moreover, Meddy cores are known to produce measurable expressions at the sea surface in the form of rotating coherent vortices, not only affecting the sea surface from beneath, but also allowing for the possibility to remotely study these deep phenomena through data gathered at the sea surface. While many past studies have focused on the properties of Meddy cores, only a handful of studies focus on the physical characteristics and behavior of the surface expressions produced. Are Meddy surface expressions different from other like vortices that dominate the physical ocean surface? What are the relationships between deep and surface mechanisms, and do any feedbacks exist? To shed light on these questions, we investigate the relationship between Meddies and their sea-surface expressions through observations using in-situ float and drifter profiles and satellite altimetry. A total of 782 Meddy cores were examined in the Northeast Atlantic using temperature and salinity data obtained by CTD and Argo during the Mecanismos de transporte e de dispersão da Água Mediterrânica no Atlântico Nordeste (MEDTRANS) project, and their corresponding sea-level expressions were geo-temporally matched in satellite altimetry data. We report several statistical properties of the sea-surface expressions of Meddies, including their mean diameter and vertical magnitude, and compare the properties of their surface features to the underlying Meddy cores. We investigate how the deep core affects the surface, and whether surface expressions may in return yield information about the underlying cores. Additionally, we examine the variability of the surface

Microsatellite variation in Donax trunculus from the Iberian Peninsula, with particular attention to Galician estuaries (NW Spain)

Science.gov (United States)

Nantón, A.; Arias-Pérez, A.; Freire, R.; Fernández-Pérez, J.; Nóvoa, S.; Méndez, J.

2017-10-01

Genetic variation and population structure information is essential for conservation and stock management policies. The wedge clam Donax trunculus is an important fishing resource in the Iberian Peninsula and in some areas, such as the northwestern Spain, wild stocks have decreased greatly. Despite this, information is mainly from the southwestern Atlantic to the northwestern Mediterranean of the Iberian Peninsula. In this study, fifteen microsatellite loci were examined at 17 localities along the Iberian Peninsula to characterize its genetic diversity and population structure. Particular attention was paid to the northwestern Atlantic area, and to test if the pattern previously described for this species is confirmed when localities distributed across the Atlantic coast are included and different microsatellite markers are used. All localities displayed similar allelic richness values and heterozygosity levels but when genetic diversity levels were compared among groups of localities, tests were significant and samples from the northwestern area (Galicia) showed the lowest values. The analysis of population structure indicated that localities from the Atlantic coast are genetically homogeneous although some samples showed significant pairwise Fst values. These values were low and Bayesian analysis of genetic differentiation did not show a consistent structure along the Atlantic coast of the Iberian Peninsula. However, Atlantic samples were genetically different from those located in Mediterranean coast, which may be explained by the existence of the Almeria-Oran front. Moreover, Fuengirola, locality situated in the Alboran Sea between the Strait of Gibraltar and Mediterranean Sea, showed significant differences from all remaining localities included in the study. Overall, the data showed the existence of genetic homogeneity along the Atlantic coast of the Iberian Peninsula and support the three management units (Atlantic Ocean, the Alboran Sea and the northwestern

Tritium in the western Mediterranean Sea during 1981 Phycemed cruise

Science.gov (United States)

Andrie, Chantal; Merlivat, Liliane

1988-02-01

We report on simultaneous hydrological and tritium data taken in the western Mediterranean Sea during April 1981 and which implement our knowledge of the spatial and temporal variability of the convection process occurring in the Northern Basin (Gulf of Lion, Ligurian Sea). The renewal time of the deep waters in the Medoc area is calculated to be 11 ± 2 years using a box-model assymption. An important local phenomenon of "cascading" off the Ebro River near the Spanish coast is, noticeable by the use of tritium data. In the Sardinia Straits area tritium data indicate very active mixing between 100 and 500 m depth. The tritium subsurface maxima in Sardinia Straits suggests the influence of not only the Levantine Intermediate Water (LIW) but also an important shallower component. In waters deeper than 500m, an active mixing occurs between the deep water and the LIW via an intermediate water mass from the Tyrrhenian Sea by "salt-fingering". Assuming a two end-member mixing. We determine the deep tritium content in the Sardinia Channel to be 1.8 TU. For comparison, the deep tritium content of the Northern Basin is equal to 1.3 TU. Tritium data relative to the Alboran Sea show that a layer of high tritium content persists all along its path from Sardifia to Gibraltar on a density surface shallower than the intermediate water. The homogeneity of the deep tritium concentrations between 1200 m depth and the bottom corroborate the upward "pumping" and westward circulation of deep waters along the continental slope of the North African Shelf. From the data measured in the Sardinia Straits and in the Alboran Sea, and upper limit of the deep advection rate of the order of 0.5 cm s-1 is estimated.

Towards a model-based understanding of the Mediterranean circulation during the Messinian Salinity Crisis

Science.gov (United States)

Simon, Dirk; Meijer, Paul

2016-04-01

Today, the Atlantic-Mediterranean gateway (the Strait of Gibraltar) and the strong evaporative loss in the east let the Mediterranean Sea attain a salinity of 2-3 g/l higher than the Atlantic Ocean. During the winter months, strong cooling of surface waters in the north forms deep water, which mixes the Mediterranean, while during summer the water column is stratified. During the Messinian Salinity Crisis (MSC, 5.97-5.33Ma) the salt concentration was high enough to reach the saturation of gypsum (~130-160 g/l) and halite (~350 g/l). This caused large deposits of these evaporites all over the basin, capturing 6% of the World Ocean salt within the Mediterranean at the time. Although several mechanisms have been proposed as to how the Mediterranean circulation might have functioned, these mechanisms have yet to be rooted in physics and tested quantitatively. Understanding circulation during the MSC becomes particularly important when comparing Mediterranean marginal to deep basins. On the one hand, many of the marginal basins in the Mediterranean are well studied, like the Sorbas basin (Spain) or the Vena del Gesso basin (Italy). On the other hand, the deep Mediterranean is less well studied, as no full record of the whole deep sequence exists. This makes it very complicated to correlate marginal and deep basin records. Here we are presenting the first steps in working towards a physics-based understanding of the mixing and stratification bahaviour of the Mediterranean Sea during the MSC. The final goal is to identify the physical mechanism needed to form such a salt brine and to understand how it differs from today's situation. We are hoping to compare our results to, and learn from, the much smaller but best available analog to the MSC, the Dead Sea, where recent overturning has been documented.

Multilocus Bayesian Estimates of Intra-Oceanic Genetic Differentiation, Connectivity, and Admixture in Atlantic Swordfish (Xiphias gladius L..

Directory of Open Access Journals (Sweden)

Brad L Smith

Full Text Available Previous genetic studies of Atlantic swordfish (Xiphias gladius L. revealed significant differentiation among Mediterranean, North Atlantic and South Atlantic populations using both mitochondrial and nuclear DNA data. However, limitations in geographic sampling coverage, and the use of single loci, precluded an accurate placement of boundaries and of estimates of admixture. In this study, we present multilocus analyses of 26 single nucleotide polymorphisms (SNPs within 10 nuclear genes to estimate population differentiation and admixture based on the characterization of 774 individuals representing North Atlantic, South Atlantic, and Mediterranean swordfish populations. Pairwise FST values, AMOVA, PCoA, and Bayesian individual assignments support the differentiation of swordfish inhabiting these three basins, but not the current placement of the boundaries that separate them. Specifically, the range of the South Atlantic population extends beyond 5°N management boundary to 20°N-25°N from 45°W. Likewise the Mediterranean population extends beyond the current management boundary at the Strait of Gibraltar to approximately 10°W. Further, admixture zones, characterized by asymmetric contributions of adjacent populations within samples, are confined to the Northeast Atlantic. While South Atlantic and Mediterranean migrants were identified within these Northeast Atlantic admixture zones no North Atlantic migrants were identified respectively in these two neighboring basins. Owing to both, the characterization of larger number of loci and a more ample spatial sampling coverage, it was possible to provide a finer resolution of the boundaries separating Atlantic swordfish populations than previous studies. Finally, the patterns of population structure and admixture are discussed in the light of the reproductive biology, the known patterns of dispersal, and oceanographic features that may act as barriers to gene flow to Atlantic swordfish.

Disentangling environmental correlates of vascular plant biodiversity in a Mediterranean hotspot.

Science.gov (United States)

Molina-Venegas, Rafael; Aparicio, Abelardo; Pina, Francisco José; Valdés, Benito; Arroyo, Juan

2013-10-01

We determined the environmental correlates of vascular plant biodiversity in the Baetic-Rifan region, a plant biodiversity hotspot in the western Mediterranean. A catalog of the whole flora of Andalusia and northern Morocco, the region that includes most of the Baetic-Rifan complex, was compiled using recent comprehensive floristic catalogs. Hierarchical cluster analysis (HCA) and detrended correspondence analysis (DCA) of the different ecoregions of Andalusia and northern Morocco were conducted to determine their floristic affinities. Diversity patterns were studied further by focusing on regional endemic taxa. Endemic and nonendemic alpha diversities were regressed to several environmental variables. Finally, semi-partial regressions on distance matrices were conducted to extract the respective contributions of climatic, altitudinal, lithological, and geographical distance matrices to beta diversity in endemic and nonendemic taxa. We found that West Rifan plant assemblages had more similarities with Andalusian ecoregions than with other nearby northern Morocco ecoregions. The endemic alpha diversity was explained relatively well by the environmental variables related to summer drought and extreme temperature values. Of all the variables, geographical distance contributed by far the most to spatial turnover in species diversity in the Baetic-Rifan hotspot. In the Baetic range, elevation was the most significant driver of nonendemic species beta diversity, while lithology and elevation were the main drivers of endemic beta diversity. Despite the fact that Andalusia and northern Morocco are presently separated by the Atlantic Ocean and the Mediterranean Sea, the Baetic and Rifan mountain ranges have many floristic similarities - especially in their western ranges - due to past migration of species across the Strait of Gibraltar. Climatic variables could be shaping the spatial distribution of endemic species richness throughout the Baetic-Rifan hotspot. Determinants

Multiple-frequency tomography of the upper mantle beneath the African/Iberian collision zone

Science.gov (United States)

Bonnin, Mickaël; Nolet, Guust; Villaseñor, Antonio; Gallart, Josep; Thomas, Christine

2014-09-01

During the Cenozoic, the geodynamics of the western Mediterranean domain has been characterized by a complex history of subduction of Mesozoic oceanic lithosphere. The final stage of these processes is proposed to have led to the development of the Calabria and Gibraltar arcs, whose formation is still under debate. In this study, we take advantage of the dense broad-band station networks now available in the Alborán Sea region, to develop a high-resolution 3-D tomographic P velocity model of the upper mantle beneath the African/Iberian collision zone that will better constraint the past dynamics of this zone. The model is based on 13200 teleseismic arrival times recorded between 2008 and 2012 at 279 stations for which cross-correlation delays are measured with a new technique in different frequency bands centred between 0.03 and 1.0 Hz, and for the first time interpreted using multiple frequency tomography. Our model shows, beneath the Alborán Sea, a strong (4 per cent) fast vertically dipping anomaly observed to at least 650 km depth. The arched shape of this anomaly, and its extent at depth, are coherent with a lithospheric slab, thus favouring the hypothesis of a westward consumption of the Ligurian ocean slab by roll-back during Cenozoic. In addition to this fast anomaly in the deep upper mantle, high intensity slow anomalies are widespread in the lithosphere and asthenosphere beneath Morocco and southern Spain. These anomalies are correlated at the surface with the position of the Rif and Atlas orogens and with Cenozoic volcanic fields. We thus confirm the presence, beneath Morocco, of an anomalous (hot?) upper mantle, but without clear indication for a lateral spreading of the Canary plume to the east.

Tomography of the upper mantle beneath the African/Iberian collision zone

Science.gov (United States)

Mickael, B.; Nolet, G.; Villasenor, A.; Josep, G.; Thomas, C.

2013-12-01

During Cenozoic, geodynamics of the western Mediterranean domain has been characterized by a complex history of subduction of Mesozoic oceanic lithosphere. The final stage of these processes is proposed to have led to the development of the Calabria and Gibraltar arcs, whose formation is still under debate. In this study we take advantage of the dense broadband-station networks now available in Alborán Sea region, to develop a high-resolution 3D tomographic P velocity model of the upper mantle beneath the African/Iberian collision zone that will bring new constraints on the past dynamics of this zone. The model is based on 13200 teleseismic arrival times recorded between 2008 and 2012 at 279 stations for which cross-correlation delays are measured with a new technique in different frequency bands centered between 0.03 and 1.0 Hz, and interpreted using multiple frequency tomography. Our model shows, beneath Alborán Sea, a strong (~ 4%) fast vertically dipping anomaly observed to at least 650 km depth. The arched shape of this anomaly and its extent at depth are coherent with a lithospheric slab, thus favoring the hypothesis of a westward consumption of the Ligurian ocean slab by roll-back during Cenozoic. In addition to this fast anomaly in the deep upper-mantle, several high intensity slow anomalies are widely observed in the lithosphere and asthenosphere beneath Morocco and southern Spain. These anomalies are correlated at surface with the position of the orogens (Rif and Atlas) and with Cenozoic volcanic fields. We thus confirm the presence, beneath Morocco, of an anomalous (hot) upper mantle, with piece of evidence for a lateral connection with the Canary volcanic islands, likely indicating a lateral spreading of the Canary plume to the east.

From the Atlas to the Rif a Crustal seismic image across Morocco: The SIMA & RIFSEIS control source wide-angle seismic reflection data

Science.gov (United States)

Carbonell, Ramon; Ayarza, Puy; Gallart, Josep; Diaz, Jordi; Harnafi, Mimoun; Levander, Alan; Teixell, Antonio

2014-05-01

The velocity structure of the crust and the geometry of the Moho across Morocco has been the main target of two recently acquired wide-angle seismic reflection transects. One is the SIMA experiment which provided seismic constraints beneath the Atlas Mountains and the second has been the RIFSEIS experiment which sampled the RIF orogen. Jointly these controlled source wide-angle seismic reflection data results in an almost 700 km, seismic profile going from the the Sahara craton across the High and Middle Atlas and Rif Mountain till the Gibraltar-Arc (Alboran). Current work on the interpretation of the seismic data-set is based on forward modeling, ray-tracing, as well as low fold wide-angle stacking. The data has resulted in a detailed crustal structure and velocity model for the Atlas Mountains and a 700 km transect revealing the irregular topography of the Moho beneath these two mountain orogens. Results indicate that the High Atlas features a moderate crustal thickness and that shortening is resolved at depth through a crustal root where the Saharan crust under-thrusts below the Moroccan crust, defining a lower crust imbrication which locally places the Moho boundary at, approximately, 40 km depth. The P-wave velocity model is characterized, in averaged, by relatively low velocities. These low deep crustal velocities together with other geophysical observables such as: conductivity estimates derived from Mt measurements; moderate Bouguer gravity anomaly; surface exposures of recent alkaline volcanics; lead the interpretation to propose that partial melts are currently emplaced in the deep crustal levels and in the upper mantle. The Moho discontinuity defines a crust which is in average relatively thin beneath the Atlas which is almost a 4000 m high orogenic belt. The resulting model supports existence of mantle upwelling as a possible mechanism that contributes, significantly, to maintain the High Atlas topography.

Caesium-137 in Marine Sediments of the Eastern Mediterranean from the Pre-Chernobyl Age to the Present

International Nuclear Information System (INIS)

Florou, Heleny; Evangeliou, Nikolaos; Kritidis, Panagiotis

2011-01-01

Caesium-137 (half-life 30.2 years) was first introduced into the marine environment as a result of the atmospheric nuclear weapon testing during 1953-1963. The second and largest contamination was the fallout after the Chernobyl accident in April 1986. Since 1986 the radiological status of the Mediterranean has been changed. During 1986 the average deposition of 137 Cs from the fallout in the Aegean Sea has been estimated to be approximately 4 kBq m -2 , whereas the respective value for the Ionian Sea (the area of 24,300 km 2 along the coasts) was 2.5 kBq m -2 . The total caesium ( 137 Cs + 134 Cs) input from Chernobyl fallout has been estimated to be 2400 TBq for the Black Sea, 820 TBq for the Aegean Sea and 600 TBq in the Ionian Sea (60 TBq in the zone of 50 km across the coasts). Although, the residence time of 137 Cs in seawater is long, it has been observed that 137 Cs has reached the bottom sediments, as the remaining period is long enough if compared to the estimated sinking time for the Mediterranean environment. The Mediterranean Sea is a semi-enclosed marine area, exchanging water, salt, heat and other physicochemical properties through the strait of Gibraltar with the Atlantic Ocean.The basin is characterized by low precipitation and high evaporation, which causes accumulation of contaminants in seawater and sediment. Taking into account the topography,one could note the importance of the eastern part of the Mediterranean,since it comprises a continuous source of interregional input (Black Sea). However,the motive of determining 137 Cs in the Greek marine territory was basic research (pre-Chernobyl age) and monitoring reasons (after Chernobyl accident). Several Greek marine systems have been examined throughout these years and the results are evaluated in the present study.

Natural and anthropogenic decadal pH decrease in the North Atlantic and Mediterranean Sea waters

Science.gov (United States)

Huertas, E.; Flecha, S.; Murata, A.; Garcia Lafuente, J.; Pérez, F. F.

2017-12-01

Seawater pH is undergoing a decreasing trend due to atmospheric CO2 absorption, a phenomenon known as Ocean Acidification (OA) that has been documented in different ocean regions. Certain marine basins are more vulnerable to OA, such as the Mediterranean Sea (MS), which is attributed to particular water circulation processes and biogeochemical features. Considering previous studies on OA in Mediterranean and Atlantic water masses, the main aim of this work was to identify for the first time the natural and anthropogenic contribution to decadal pH variations. Therefore, an archetypal analysis was applied to pH measurements and other biogeochemical variables collected in the Strait of Gibraltar during 10 years. Our results reveal that the biological component of the pH change in the Western Mediterranean Deep Water (WMDW) (ΔpHWMDW) represents around 56% of the total decadal pH decrease observed, highlighting the relevance of the remineralization occurring in the Alboran basin, where the WMDW resides before leaving the MS. On the other hand, neither natural nor anthropogenic forcing on the pH change in the Levantine Intermediate Water (ΔpHLIW) was detected, as pH variation was negligible. As for the North Atlantic Central Water (NACW), atmospheric CO2 uptake was responsible of 58% of the ΔpHNACW, likely related to permanent contact with the atmosphere. Additionally, estimations of the approximated ages of the NACW, LIW and WMDW in the SG of about 8, 34 and 32 years respectively have been obtained. Our results show that Mediterranean waters undergo changes in their biogeochemical characteristics during transit through the SG and gives insights on the main mechanisms affecting pH variations occurring from their formation sites to the SG.

New data regarding the migration of spoonbills (Platalea leucorodia breeding in the Danube Delta, based on color ring resightings

Directory of Open Access Journals (Sweden)

KISS J. Botond

2007-10-01

Full Text Available Based on our previous knowledge the Spoonbills breeding in Europe follow three main migratory routes towards Africa. Populations from the western part of the continent follow the East Atlantic coast of Europe, passing through Gibraltar and winter in Western Africa. The Central European populations fly south to Italy, Sicily, then are crossing the Mediterranean Sea towards Tunis, Libya, Israel and Egypt, sometimes flying over the Sahara desert as far as to Eastern- and Central Africa . Spoonbills from Eastern Europe follow the coast of the Black and Marmora Seas, then the eastern coast of the Mediterranean, where some are spending the winter. Others reach EastAfrica or even go further east to Iran or India. A color marking study – using engraved PVC rings – was launched in 2002, to follow the migration of Spoonbills breeding in the Danube Delta. From the 219 birds ringed 20 were resighted totalizing 23 observations. These recent resightings suggest a post breeding movement and migratory route with much a broader angle – between Spain in the west and Oman in the east. The birds were observed in 10 countries from Europe, Africa and Asia. The observation of a color ringed individual at Biharugra, Hungary early in migration indicates a true postbreeding dispersal towards north-east. Other resightings in Croatia and Italy suggest an orientation towards the main migratory route of the Central European population. The resighting of an individual in Spain indicates population exchanges even with Western European spoonbills, moreover as birds from Romania were observed in Tunisia together with spoonbills from Western and Central European populations. We consider that in the future especially using colorringing or satellite telemetry we may understand much better the migratory pathways of Spoonbills from Romania.

Scenarios in the development of Mediterranean cyclones

Directory of Open Access Journals (Sweden)

M. Romem

2007-07-01

Full Text Available The Mediterranean is one of the most cyclogenetic regions in the world. The cyclones are concentrated along its northern coasts and their tracks are oriented more or less west-east, with several secondary tracks connecting them to Europe and to North Africa. The aim of this study is to examine scenarios in the development of Mediterranean cyclones, based on five selected winter seasons (October–March. We detected the cyclones subjectively using 6-hourly Sea-Level Pressure maps, based on the NCAR/NCEP reanalysis archive.

HMSO (1962 has shown that most Mediterranean cyclones (58% enter the Mediterranean from the Atlantic Ocean (through Biscay and Gibraltar, and from the south-west, the Sahara Desert, while the rest are formed in the Mediterranean Basin itself. Our study revealed that only 13% of the cyclones entered the Mediterranean, while 87% were generated in the Mediterranean Basin. The entering cyclones originate in three different regions: the Sahara Desert (6%, the Atlantic Ocean (4%, and Western Europe (3%.

The cyclones formed within the Mediterranean Basin were found to generate under the influence of external cyclonic systems, i.e. as "daughter cyclones" to "parent cyclones" or troughs. These parent systems are located in three regions: Europe (61%, North Africa and the Red Sea (34.5% and the Mediterranean Basin itself (4.5%. The study presents scenarios in the development of Mediterranean cyclones during the winter season, emphasizing the cyclogenesis under the influence of various external forcing.

The large difference with respect to the findings of HMSO (1962 is partly explained by the dominance of spring cyclones generating in the Sahara Desert, especially in April and May that were not included in our study period.

Genetic differentiation and phylogeography of Mediterranean-North Eastern Atlantic blue shark (Prionace glauca, L. 1758 using mitochondrial DNA: panmixia or complex stock structure?

Directory of Open Access Journals (Sweden)

Agostino Leone

2017-12-01

Full Text Available Background The blue shark (Prionace glauca, Linnaeus 1758 is one of the most abundant epipelagic shark inhabiting all the oceans except the poles, including the Mediterranean Sea, but its genetic structure has not been confirmed at basin and interoceanic distances. Past tagging programs in the Atlantic Ocean failed to find evidence of migration of blue sharks between the Mediterranean and the adjacent Atlantic, despite the extreme vagility of the species. Although the high rate of by-catch in the Mediterranean basin, to date no genetic study on Mediterranean blue shark was carried out, which constitutes a significant knowledge gap, considering that this population is classified as “Critically Endangered”, unlike its open-ocean counterpart. Methods Blue shark phylogeography and demography in the Mediterranean Sea and North-Eastern Atlantic Ocean were inferred using two mitochondrial genes (Cytb and control region amplified from 207 and 170 individuals respectively, collected from six localities across the Mediterranean and two from the North-Eastern Atlantic. Results Although no obvious pattern of geographical differentiation was apparent from the haplotype network, Φst analyses indicated significant genetic structure among four geographical groups. Demographic analyses suggest that these populations have experienced a constant population expansion in the last 0.4–0.1 million of years. Discussion The weak, but significant, differences in Mediterranean and adjacent North-eastern Atlantic blue sharks revealed a complex phylogeographic structure, which appears to reject the assumption of panmixia across the study area, but also supports a certain degree of population connectivity across the Strait of Gibraltar, despite the lack of evidence of migratory movements observed by tagging data. Analyses of spatial genetic structure in relation to sex-ratio and size could indicate some level of sex/stage biased migratory behaviour.

Spectral Estimation of UV-Vis Absorbance Time Series for Water Quality Monitoring

Directory of Open Access Journals (Sweden)

Leonardo Plazas-Nossa

2017-05-01

Full Text Available Context: Signals recorded as multivariate time series by UV-Vis absorbance captors installed in urban sewer systems, can be non-stationary, yielding complications in the analysis of water quality monitoring. This work proposes to perform spectral estimation using the Box-Cox transformation and differentiation in order to obtain stationary multivariate time series in a wide sense. Additionally, Principal Component Analysis (PCA is applied to reduce their dimensionality. Method: Three different UV-Vis absorbance time series for different Colombian locations were studied: (i El-Salitre Wastewater Treatment Plant (WWTP in Bogotá; (ii Gibraltar Pumping Station (GPS in Bogotá; and (iii San-Fernando WWTP in Itagüí. Each UV-Vis absorbance time series had equal sample number (5705. The esti-mation of the spectral power density is obtained using the average of modified periodograms with rectangular window and an overlap of 50%, with the 20 most important harmonics from the Discrete Fourier Transform (DFT and Inverse Fast Fourier Transform (IFFT. Results: Absorbance time series dimensionality reduction using PCA, resulted in 6, 8 and 7 principal components for each study site respectively, altogether explaining more than 97% of their variability. Values of differences below 30% for the UV range were obtained for the three study sites, while for the visible range the maximum differences obtained were: (i 35% for El-Salitre WWTP; (ii 61% for GPS; and (iii 75% for San-Fernando WWTP. Conclusions: The Box-Cox transformation and the differentiation process applied to the UV-Vis absorbance time series for the study sites (El-Salitre, GPS and San-Fernando, allowed to reduce variance and to eliminate ten-dency of the time series. A pre-processing of UV-Vis absorbance time series is recommended to detect and remove outliers and then apply the proposed process for spectral estimation. Language: Spanish.

Raptor mortality in wind farms of southern Spain: mitigation measures on a major migration bottleneck area

Energy Technology Data Exchange (ETDEWEB)

Gallego, Antonio-Roman Munoz; Lucas, Manuela De; Casado, Eva; Ferrer, Miguel

2011-07-01

Full text: To assess and monitor the impact of wind farms on fauna is crucial if we want to achieve ecologically sustainable development of this renewable energy resource. Today there are clear evidences that the probability of raptor collision depends critically on species behaviour and weather conditions, and the topographic factors related to each windmill. In our study area EIA were not able to predict this differential risk and in these circumstances mitigating the causes of bird mortality becomes a task of major importance, especially to those wind farms located in the Strait of Gibraltar, a water crossing of 14 km at its shortest distance acting as a major migration bottleneck for Paleo-African soaring migrants. We collected all available information on raptor collision from 1992, when the first wind farm was installed, and from 2005 until present a total of 262 turbines, grouped into 20 wind farms, were surveyed in a daily basis through a surveillance program with the main goal of register the actual mortality of birds. A total of 1291 raptors of 19 species were found of which 78.5% correspond to two species, the griffon vulture (Gyps fulvus) and the kestrel (Falco tinnunculus). In order to mitigate the impact on raptors, and particularly on the griffon vulture, in 2007 a program based on selective stopping of turbines was imposed, in collaboration with the environmental competent authority, on new approved projects. During 2008 there was a reduction in mortality by 48%, which remained in 2009 with a remarkably lower economic cost. An analysis of the temporal collision patterns will be presented and discussed, with special attention to those species suffering higher mortality rate, and to those who have some degree of threat. (Author)

Underwater Ambient Noise in a Baleen Whale Migratory Habitat Off the Azores

Directory of Open Access Journals (Sweden)

Miriam Romagosa

2017-04-01

Full Text Available Assessment of underwater noise is of particular interest given the increase in noise-generating human activities and the potential negative effects on marine mammals which depend on sound for many vital processes. The Azores archipelago is an important migratory and feeding habitat for blue (Balaenoptera musculus, fin (Balaenoptera physalus and sei whales (Balaenoptera borealis en route to summering grounds in northern Atlantic waters. High levels of low frequency noise in this area could displace whales or interfere with foraging behavior, impacting energy intake during a critical stage of their annual cycle. In this study, bottom-mounted Ecological Acoustic Recorders were deployed at three Azorean seamounts (Condor, Açores, and Gigante to measure temporal variations in background noise levels and ship noise in the 18–1,000 Hz frequency band, used by baleen whales to emit and receive sounds. Monthly average noise levels ranged from 90.3 dB re 1 μPa (Açores seamount to 103.1 dB re 1 μPa (Condor seamount and local ship noise was present up to 13% of the recording time in Condor. At this location, average contribution of local boat noise to background noise levels is almost 10 dB higher than wind contribution, which might temporally affect detection ranges for baleen whale calls and difficult communication at long ranges. Given the low time percentatge with noise levels above 120 dB re 1 μPa found here (3.3% at Condor, we woud expect limited behavioral responses to ships from baleen whales. Sound pressure levels measured in the Azores are lower than those reported for the Mediterranean basin and the Strait of Gibraltar. However, the currently unknown effects of baleen whale vocalization masking and the increasing presence of boats at the monitored sites underline the need for continuous monitoring to understand any long-term impacts on whales.

ESTIMACIÓN DEL EXPONENTE DE HURST Y DIMENSIÓN FRACTAL PARA EL ANÁLISIS DE SERIES DE TIEMPO DE ABSORBANCIA UV-VIS

Directory of Open Access Journals (Sweden)

Leonardo Plazas Nossa

2014-01-01

Full Text Available El objetivo de este trabajo es estimar el exponente o parámetro de Hurst y la dimensión fractal para el análisis de series de tiempo de espectrometría UV-Vis, utilizando el análisis de componentes principales PCA (Principal Component Analysis. El análisis se realiza para comprender si las series de tiempo de absorbancia UV-Vis son persistentes, anti-persistentes, determinísticas o si son ruido blanco. Se utilizaron tres diferentes series de tiempo de absorbancia UV-Vis para tres diferentes sitios de estudio: (i Planta de tratamiento de aguas residuales Salitre (PTAR en Bogotá; (ii Estación elevadora de Gibraltar en Bogotá (EEG; y (iii Planta de tratamiento de aguas residuales San Fernando (PTAR en Itagüí (sur de Medellín. Cada una de las series de tiempo tiene igual número de muestras (5705. Se redujo la dimensionalidad de los espectros de absorbancia, dada su alta correlación, con PCA y se utilizó para cada sitio de estudio la primera componente principal. Esta componente principal explicó entre el 82% al 94% de la variabilidad para los tres sitios de estudio. Se determinaron los exponentes de Hurst: (i 0.8 para PTAR Salitre; (ii 0.85 para EEG; y (iii 0.89 para PTAR San Fernando. A partir de los valores de los exponentes de Hurst se determinan las dimensiones fractales para las tres series de tiempo de absorbancia UV-Vis en los tres sitios de estudio y se obtiene en promedio una dimensión fractal de 1153. Las tres series de tiempo de absorbancia UV-Vis son persistentes y con alta auto-similitud, dado que el exponente de Hurst es mayor a 0.5.

Surface circulation in the Gulf of Cadiz: Model and mean flow structure

Science.gov (United States)

Peliz, Alvaro; Dubert, Jesus; Marchesiello, Patrick; Teles-Machado, Ana

2007-11-01

The mean flow structure of the Gulf of Cadiz is studied using a numerical model. The model consists of a set of one-way nested configurations attaining resolutions on the order of 2.6 km in the region of the Gulf of Cadiz. In the large-scale configuration, the entrainment of the Mediterranean Water is parameterized implicitly through a nudging term. In medium- and small-scale nested configurations, the Mediterranean outflow is introduced explicitly. The model reproduces all the known features of the Azores Current and of the circulation inside the Gulf of Cadiz. A realistic Mediterranean Undercurrent is generated and Meddies develop at proper depths on the southwest tip of the Iberian slope. The hypothesis that the Azores Current may generate in association with the Mediterranean outflow (β-plume theories) is confirmed by the model results. The time-mean flow is dominated by a cyclonic cell generated in the gulf which expands westward and has transports ranging from 4 to 5 Sv. The connection between the cell and the Azores Current is analyzed. At the scale of the Gulf, the time-mean flow cell is composed by the westward Mediterranean Undercurrent, and by a counterflow running eastward over the outer edge of the Mediterranean Undercurrent deeper vein, as the latter is forced downslope. This counterflow feeds the entrainment at the depths of the Mediterranean Undercurrent and the Atlantic inflow at shallower levels. Coastward and upslope of this recirculation cell, a second current running equatorward all the way along the northern part of the gulf is revealed. This current is a very robust model result that promotes continuity between the southwestern Iberian coast and the Strait of Gibraltar, and helps explain many observations and recurrent SST features of the Gulf of Cadiz.

Matrilineal Heritage in Southern Iberia Reveals Deep Genetic Links between Continents.

Science.gov (United States)

Hernández, Candela L; Calderón, Rosario

2017-03-01

Within the Mediterranean Basin, the Iberian Peninsula has been a focus of attraction for several cultures and civilizations from its prehistory and history, making it a target territory for studying human migration patterns and peopling processes using a wide and heterogeneous spectrum of genomic markers. While its Cantabrian fringe represents the most regularly analysed area in terms of its mitochondrial diversity, the absence of monographic surveys on the maternal genetic composition of southern Iberians (i.e., Andalusians) is striking. In this work, we present a comprehensive view of various aspects of the human maternal heritage of the autochthonous Andalusian population regarding specific mitochondrial haplogroups considered key candidates to determine the genetic relationship between Europe and Africa. Data reveal that southern Iberian populations do not have genetically homogeneous mitochondrial DNA profiles, and their observed genetic affinity with north-western African populations represents strong signals of old, sustained and bidirectional human movements between the northern and southern shores of the western Mediterranean. Thorough analyses of African mtDNA haplogroups have shown that the most relevant African contribution within Iberian Peninsula could be explained as a consequence of prehistoric events. The subsequent historic episodes helped to strengthen the ties between both shores. In southern Iberia, mitochondrial and other genetic markers show that the Strait of Gibraltar together with its surrounding maritime areas should be considered a bridge between continents. More broadly, the Mediterranean Sea has acted as a transport surface, that is, as a permeable barrier to human migrations from prehistoric and historic times. In conclusion, this research contributes to our knowledge of processes that have shaped the recent human genetic history in the Mediterranean and, more specifically, of the population dynamics that the inhabitants of southern

Mineralogía y génesis de la fracción fina de la serie de El Rinconcillo (formaciones Flysch del Campo de Gibraltar. SW de España

Directory of Open Access Journals (Sweden)

Carrasco, F.

1987-04-01

Full Text Available The stratigraphic sequence of El Rinconcillo belong to the Algeciras Unit. Illite, kaolinite, chlorite and interstratified illite-smectite are common minerals for materials of this Unit, but a high proportion of Fe-Al smectites and sporadic presence of palygorskite is characteristic of the series of El Rinconcillo in relation to the others studied in Northern Africa and Southwestern Spain. Illite, kaolinite and chlorite are considered to be inherited minerals. Smectides and interestratified illite-smectite are also inherited in the turbidites but they were formed in the source area by transformation from illite under different weathering degree. Finally, the formation of palygorskite in the Middle Eocene carbonatic turbidites accompanied by many smectide, and no kaolinite, is difficult to explain in relation with turbiditic materials. It is more feasible to suppose a removal process that implicates the existence of a previous clay sediment in which such association -palygorskite + smectite- took place by transformation and/or by neoformation.La serie de El Rinconcillo, atribuida a la Unidad de Algeciras, presenta variaciones mineralógicas notables respecto a las series "tipo" definidas en esta Unidad tanto en el norte de Africa como en el suroeste de España. Aunque en gran parte la mineralogía es común con otras series de esta Unidad (ilita, caolinita, clorita, interestratificados I-E, se diferencia no obstante, por la elevada proporción de esmectita Fe-Al y la presencia esporádica de paligorskita. Ilita, caolinta y clorita, se consideran minerales heredados. La esmectita y los interestratificados I-E son también heredados en las turbiditas, procedentes de la transformación de la ilita en el área fuente bajo diferente grado de meteorización. Finalmente, la formación de paligorskita en las turbidítas calcáreas del Eoceno medio acompañada por esmectita y la ausencia de caolinita en este tramo, es difícil de explicar en relación con los materiales turbidíticos. Parece más probable que las corrientes de turbidez hayan arrastrado sedimentos arcillosos preexistentes en los que ha podido tener lugar la transformación y/o neoformación de estos minerales.

Violent storms within the sea: Dense water formation episodes in the Mediterranean.

Science.gov (United States)

Salat, J.

2009-09-01

The Mediterranean is a semi enclosed basin which receives surface water from the Atlantic Ocean. Most of this water is returned into the Ocean with higher density, spreading at more than 1000 m depth (the rest is transported by the atmosphere and the rivers to the Ocean surface). In terms of water budget, the Mediterranean is considered an evaporation basin, but the loss of water is neither the only process that increases the water density nor it is a steady or uniform process. The factors affecting the water density, temperature and salinity, are driven by mass and heat exchanges with the atmosphere. Those exchanges may be by direct contact or mediated by the land. Therefore, changes in water density depend on the water circulation and local weather conditions, both with seasonal and geographical constraints. As the compressibility of water is very low, stratification is expected and horizontal motion is the predominant in the sea interior. Among the few processes that may introduce a vertical component in the water motion are surface heat loss or evaporation that increase the surface water density triggering convective cells. Such processes will be enhanced by surface cooling or by dry continental winds, and counterbalanced by rain, river runoff, solar heating and condensation. Therefore dense water formation are more likely to occur when sea surface temperature is higher than the surface air temperature. There are several scales of convective motions in the ocean, starting from the formation of the surface mixed layer during summer, by night cooling, breezes, and occasional wind storms. During autumn and winter, the vertical scale of the mixing is increasing by steps, through wind storms and progressive cooling, to easily reach the bottom over the continental shelves, typically not deeper than 150 m. However, as the Gibraltar sill is relatively shallow (~350 m) in relation to the average Mediterranean basin (2000-3000 m), the stratification of the deeper layers

The El Asnam 1980 October 10 inland earthquake: a new hypothesis of tsunami generation

Science.gov (United States)

Roger, J.; Hébert, H.; Ruegg, J.-C.; Briole, P.

2011-06-01

The Western Mediterranean Sea is not considered as a high seismic region. Only several earthquakes with magnitude above five occur each year and only a handful have consequences on human beings and infrastructure. The El Asnam (Algeria) earthquake of 1980 October 10 with an estimated magnitude Ms= 7.3 is one of the most destructive earthquakes recorded in northern Africa and more largely in the Western Mediterranean Basin. Although it is located inland, it is known to have been followed by a small tsunami recorded on several tide gauges along the southeastern Spanish Coast. In 1954, a similar earthquake having occurred at the same location induced a turbidity current associated to a submarine landslide, which is widely known to have cut submarine phone cables far from the coast. This event was followed by a small tsunami attributed to the landslide. Thus the origin of the tsunami of 1980 was promptly attributed to the same kind of submarine slide. As no evidence of such mass movement was highlighted, and because the tsunami wave periods does not match with a landslide origin in both cases (1954 and 1980), this study considers two rupture scenarios, that the coseismic deformation itself (of about 10 cm off the Algerian coast near Ténès) is sufficient to produce a low amplitude (several centimetres) tsunami able to reach the Spanish southeastern coast from Alicante to Algeciras (Gibraltar strait to the west). After a discussion concerning the proposed rupture scenarios and their respective parameters, numerical tsunami modelling is performed on a set of bathymetric grids. Then the results of wave propagation and amplification (maximum wave height maps) are discussed, with a special attention to Alicante (Spain) Harbour where the location of two historical tide gauges allows the comparison between synthetic mareograms and historical records showing sufficient signal amplitude. This study is part of the active tsunami hazard assessment in Mediterranean Sea especially

Climatic and topographical correlates of plant palaeo- and neoendemism in a Mediterranean biodiversity hotspot.

Science.gov (United States)

Molina-Venegas, Rafael; Aparicio, Abelardo; Lavergne, Sébastien; Arroyo, Juan

2017-01-01

Understanding the evolutionary and ecological forces contributing to the emergence of biodiversity hotspots is of outstanding importance to elucidate how they may withstand current climate changes. Here we explored patterns of phylogenetic and non-phylogenetic plant endemism in a Mediterranean biodiversity hotspot. We hypothesized that areas with wet and equable climatic conditions would be prone to long-term persistence of endemic lineages (palaeoendemism), whilst areas of recent local speciation (neoendemism) would be more related to harsher environmental conditions and to high topographical relief promoting speciation. We focused on the Baetic-Rifan biodiversity hotspot (southern Iberian Peninsula and northern Morocco) in combination with molecular phylogenetic information and relative phylogenetic endemism (RPE), a recent phylogenetic measure of endemism, allowing us to discern centres of palaeo- from those of neoendemism. Using eco-geographical regions as study units, we explored correlations between both RPE and endemic species richness with precipitation- and temperature-related variables and with elevation range. Centres of neoendemism were concentrated towards the easternmost part of the hotspot, while centres of palaeoendemism were clustered in the vicinity of the Strait of Gibraltar. The RPE index, indicating more palaeoendemism, was positively correlated with total annual precipitation, while endemic species richness showed a poor correlation. In contrast, elevation range and mean annual temperature were poor predictors of RPE, despite elevation range showing a strong correlation with endemic species richness. The Baetic-Rifan biodiversity hotspot shows clearly differentiated centres of neo- and palaeoendemism. Topographical relief may have driven evolutionary diversification of newly evolved species, while water availability seems more critical for the long-term persistence of ancient lineages in refuge areas of smoother topography. Given climatic

Detection of Outliers and Imputing of Missing Values for Water Quality UV-VIS Absorbance Time Series

Directory of Open Access Journals (Sweden)

Leonardo Plazas-Nossa

2017-01-01

Full Text Available Context: The UV-Vis absorbance collection using online optical captors for water quality detection may yield outliers and/or missing values. Therefore, data pre-processing is a necessary pre-requisite to monitoring data processing. Thus, the aim of this study is to propose a method that detects and removes outliers as well as fills gaps in time series. Method: Outliers are detected using Winsorising procedure and the application of the Discrete Fourier Transform (DFT and the Inverse of Fast Fourier Transform (IFFT to complete the time series. Together, these tools were used to analyse a case study comprising three sites in Colombia ((i Bogotá D.C. Salitre-WWTP (Waste Water Treatment Plant, influent; (ii Bogotá D.C. Gibraltar Pumping Station (GPS; and, (iii Itagüí, San Fernando-WWTP, influent (Medellín metropolitan area analysed via UV-Vis (Ultraviolet and Visible spectra. Results: Outlier detection with the proposed method obtained promising results when window parameter values are small and self-similar, despite that the three time series exhibited different sizes and behaviours. The DFT allowed to process different length gaps having missing values. To assess the validity of the proposed method, continuous subsets (a section of the absorbance time series without outlier or missing values were removed from the original time series obtaining an average 12% error rate in the three testing time series. Conclusions: The application of the DFT and the IFFT, using the 10% most important harmonics of useful values, can be useful for its later use in different applications, specifically for time series of water quality and quantity in urban sewer systems. One potential application would be the analysis of dry weather interesting to rain events, a feat achieved by detecting values that correspond to unusual behaviour in a time series. Additionally, the result hints at the potential of the method in correcting other hydrologic time series.

Integrative inference of population history in the Ibero-Maghrebian endemic Pleurodeles waltl (Salamandridae).

Science.gov (United States)

Gutiérrez-Rodríguez, Jorge; Barbosa, A Márcia; Martínez-Solano, Íñigo

2017-07-01

Inference of population histories from the molecular signatures of past demographic processes is challenging, but recent methodological advances in species distribution models and their integration in time-calibrated phylogeographic studies allow detailed reconstruction of complex biogeographic scenarios. We apply an integrative approach to infer the evolutionary history of the Iberian ribbed newt (Pleurodeles waltl), an Ibero-Maghrebian endemic with populations north and south of the Strait of Gibraltar. We analyzed an extensive multilocus dataset (mitochondrial and nuclear DNA sequences and ten polymorphic microsatellite loci) and found a deep east-west phylogeographic break in Iberian populations dating back to the Plio-Pleistocene. This break is inferred to result from vicariance associated with the formation of the Guadalquivir river basin. In contrast with previous studies, North African populations showed exclusive mtDNA haplotypes, and formed a monophyletic clade within the Eastern Iberian lineage in the mtDNA genealogy. On the other hand, microsatellites failed to recover Moroccan populations as a differentiated genetic cluster. This is interpreted to result from post-divergence gene flow based on the results of IMA2 and Migrate analyses. Thus, Moroccan populations would have originated after overseas dispersal from the Iberian Peninsula in the Pleistocene, with subsequent gene flow in more recent times, implying at least two trans-marine dispersal events. We modeled the distribution of the species and of each lineage, and projected these models back in time to infer climatically favourable areas during the mid-Holocene, the last glacial maximum (LGM) and the last interglacial (LIG), to reconstruct more recent population dynamics. We found minor differences in climatic favourability across lineages, suggesting intraspecific niche conservatism. Genetic diversity was significantly correlated with the intersection of environmental favourability in the LIG and

Climatic and topographical correlates of plant palaeo- and neoendemism in a Mediterranean biodiversity hotspot

Science.gov (United States)

Molina-Venegas, Rafael; Aparicio, Abelardo; Lavergne, Sébastien; Arroyo, Juan

2017-01-01

Background and Aims Understanding the evolutionary and ecological forces contributing to the emergence of biodiversity hotspots is of outstanding importance to elucidate how they may withstand current climate changes. Here we explored patterns of phylogenetic and non-phylogenetic plant endemism in a Mediterranean biodiversity hotspot. We hypothesized that areas with wet and equable climatic conditions would be prone to long-term persistence of endemic lineages (palaeoendemism), whilst areas of recent local speciation (neoendemism) would be more related to harsher environmental conditions and to high topographical relief promoting speciation. Methods We focused on the Baetic–Rifan biodiversity hotspot (southern Iberian Peninsula and northern Morocco) in combination with molecular phylogenetic information and relative phylogenetic endemism (RPE), a recent phylogenetic measure of endemism, allowing us to discern centres of palaeo- from those of neoendemism. Using eco-geographical regions as study units, we explored correlations between both RPE and endemic species richness with precipitation- and temperature-related variables and with elevation range. Key Results Centres of neoendemism were concentrated towards the easternmost part of the hotspot, while centres of palaeoendemism were clustered in the vicinity of the Strait of Gibraltar. The RPE index, indicating more palaeoendemism, was positively correlated with total annual precipitation, while endemic species richness showed a poor correlation. In contrast, elevation range and mean annual temperature were poor predictors of RPE, despite elevation range showing a strong correlation with endemic species richness. Conclusions The Baetic–Rifan biodiversity hotspot shows clearly differentiated centres of neo- and palaeoendemism. Topographical relief may have driven evolutionary diversification of newly evolved species, while water availability seems more critical for the long-term persistence of ancient lineages in

Phylogeography of a widespread species: pre-glacial vicariance, refugia, occasional blocking straits and long-distance migrations.

Science.gov (United States)

Santiso, Xabier; Lopez, Lúa; Retuerto, Rubén; Barreiro, Rodolfo

2016-01-13

Phylogeographic studies give us the opportunity to reconstruct the historical migrations of species and link them with climatic and geographic variation. They are, therefore, a key tool to understanding the relationships among biology, geology and history. One of the most interesting biogeographical areas of the world is the Mediterranean region. However, in this area, the description of concordant phylogeographic patterns is quite scarce, which limits the understanding of evolutionary patterns related to climate. Species with one-dimensional distribution ranges, such as the strawberry tree (Arbutus unedo), are particularly useful to unravel these patterns. Here, we describe its phylogeographic structure and check for concordance with patterns seen in other Mediterranean plants: longitudinal/latitudinal clines of diversity, evidence for glacial refugia and the role of sea straits in dispersal. We also identify the most likely source for the disjunct Irish population. With this aim, we sequenced four chloroplast non-coding fragments of A. unedo from 23 populations covering its whole distribution. We determined the genetic diversity, population structure, haplotype genealogy and time to the most recent common ancestor. The genealogy revealed two clades that separated during the last 700 ky but before the last glacial maximum. One clade occupies Atlantic Iberia and North Africa, while the other occurs in the Western Mediterranean. The Eastern Mediterranean is inhabited by newer haplotypes derived from both clades, while the Irish population is closely related to Iberian demes. The straits of Sicily and Gibraltar partially restricted the gene flow. We concluded that a vicariance event during the Late Quaternary in the western end of the species' range followed by eastward migration seems a likely explanation for the observed phylogeographic pattern. The role of straits indicates an occasional communication between Europe and North Africa, suggesting that the latter was

Surface oceanographic fronts influencing deep-sea biological activity: Using fish stable isotopes as ecological tracers

Science.gov (United States)

Louzao, Maite; Navarro, Joan; Delgado-Huertas, Antonio; de Sola, Luis Gil; Forero, Manuela G.

2017-06-01

Ecotones can be described as transition zones between neighbouring ecological systems that can be shaped by environmental gradients over a range of space and time scales. In the marine environment, the detection of ecotones is complex given the highly dynamic nature of marine systems and the paucity of empirical data over ocean-basin scales. One approach to overcome these limitations is to use stable isotopes from animal tissues since they can track spatial oceanographic variability across marine systems and, in turn, can be used as ecological tracers. Here, we analysed stable isotopes of deep-sea fishes to assess the presence of ecological discontinuities across the western Mediterranean. We were specifically interested in exploring the connection between deep-sea biological activity and particular oceanographic features (i.e., surface fronts) occurring in the pelagic domain. We collected samples for three different abundant deep-sea species in May 2004 from an experimental oceanographic trawling cruise (MEDITS): the Mictophydae jewel lanternfish Lampanyctus crocodilus and two species of the Gadidae family, the silvery pout Gadiculus argenteus and the blue whiting Micromesistius poutassou. The experimental survey occurred along the Iberian continental shelf and the upper and middle slopes, from the Strait of Gibraltar in the SW to the Cape Creus in the NE. The three deep-sea species were highly abundant throughout the study area and they showed geographic variation in their isotopic values, with decreasing values from north to south disrupted by an important change point around the Vera Gulf. Isotopic latitudinal gradients were explained by pelagic oceanographic conditions along the study area and confirm the existence of an ecotone at the Vera Gulf. This area could be considered as an oceanographic boundary where waters of Atlantic origin meet Mediterranean surface waters forming important frontal structures such as the Almeria-Oran front. In fact, our results

Precise dating of the Middle-to-Upper Paleolithic transition in Murcia (Spain supports late Neandertal persistence in Iberia

Directory of Open Access Journals (Sweden)

João Zilhão

2017-11-01

Full Text Available The late persistence in Southern Iberia of a Neandertal-associated Middle Paleolithic is supported by the archeological stratigraphy and the radiocarbon and luminescence dating of three newly excavated localities in the Mula basin of Murcia (Spain. At Cueva Antón, Mousterian layer I-k can be no more than 37,100 years-old. At La Boja, the basal Aurignacian can be no less than 36,500 years-old. The regional Middle-to-Upper Paleolithic transition process is thereby bounded to the first half of the 37th millennium Before Present, in agreement with evidence from Andalusia, Gibraltar and Portugal. This chronology represents a lag of minimally 3000 years with the rest of Europe, where that transition and the associated process of Neandertal/modern human admixture took place between 40,000 and 42,000 years ago. The lag implies the presence of an effective barrier to migration and diffusion across the Ebro river depression, which, based on available paleoenvironmental indicators, would at that time have represented a major biogeographical divide. In addition, (a the Phlegraean Fields caldera explosion, which occurred 39,850 years ago, would have stalled the Neandertal/modern human admixture front because of the population sink it generated in Central and Eastern Europe, and (b the long period of ameliorated climate that came soon after (Greenland Interstadial 8, during which forests underwent a marked expansion in Iberian regions south of 40°N would have enhanced the “Ebro Frontier” effect. These findings have two broader paleoanthropological implications: firstly, that, below the Ebro, the archeological record made prior to 37,000 years ago must be attributed, in all its aspects and components, to the Neandertals (or their ancestors; secondly, that modern human emergence is best seen as an uneven, punctuated process during which long-lasting barriers to gene flow and cultural diffusion could have existed across rather short distances, with

Molecular phylogeny and evolutionary history of Moricandia DC (Brassicaceae

Directory of Open Access Journals (Sweden)

Francisco Perfectti

2017-10-01

Full Text Available Background The phylogeny of tribe Brassiceae (Brassicaceae has not yet been resolved because of its complex evolutionary history. This tribe comprises economically relevant species, including the genus Moricandia DC. This genus is currently distributed in North Africa, Middle East, Central Asia and Southern Europe, where it is associated with arid and semi-arid environments. Although some species of Moricandia have been used in several phylogenetic studies, the phylogeny of this genus is not well established. Methods Here we present a phylogenetic analysis of the genus Moricandia using a nuclear (the internal transcribed spacers of the ribosomal DNA and two plastidial regions (parts of the NADH dehydrogenase subunit F gene and the trnT-trnF region. We also included in the analyses members of their sister genus Rytidocarpus and from the close genus Eruca. Results The phylogenetic analyses showed a clear and robust phylogeny of the genus Moricandia. The Bayesian inference tree was concordant with the maximum likelihood and timing trees, with the plastidial and nuclear trees showing only minor discrepancies. The genus Moricandia appears to be formed by two main lineages: the Iberian clade including three species, and the African clade including the four species inhabiting the Southern Mediterranean regions plus M. arvensis. Discussion We dated the main evolutionary events of this genus, showing that the origin of the Iberian clade probably occurred after a range expansion during the Messinian period, between 7.25 and 5.33 Ma. In that period, an extensive African-Iberian floral and faunal interchange occurred due to the existence of land bridges between Africa and Europa in what is, at present-days, the Strait of Gibraltar. We have demonstrated that a Spanish population previously ascribed to Rytidocarpus moricandioides is indeed a Moricandia species, and we propose to name it as M. rytidocarpoides sp. nov. In addition, in all the phylogenetic

A project to study SOC evolution after land use change combining chronosequence and gradient methods

Science.gov (United States)

Gabarron-Galeote, Miguel A.; van Wesemael, Bas

2013-04-01

In the last decades the interest in the global C budget has increased enormously and soils have a great importance in this issue since they contain about twice as much carbon as the atmosphere. Land use change (LUC) can cause a change in land cover and an associated change in carbon stocks in soils, so it has a major impact in the balance between inputs and outputs of soil organic carbon (SOC). Improved understanding of land-use impacts on the world's terrestrial carbon balance is thus a necessary part of the global effort to mitigate climate change. The aim of this project is to predict the effects of land use and land management change on (SOC) stocks, characterizing the soil organic carbon cycle and its relationship to the vegetal cover in croplands abandoned different years ago and under different Mediterranean climatic conditions in South of Spain. The study area is located in the Cordillera Bética Litoral, in South of Spain. In this area, a climatic gradient can be observed from West to East: from >1,500 mm year-1 in the Strait of Gibraltar to <250 mm year-1 in the Cabo de Gata. More specifically, the study is focussed on three different areas from the climatic conditions point of view: Gaucín (1010 mm year-1), Almogía, (576 mm year-1) and Gérgal (240 mm year-1). By means of the analyses of aerial photographs (1956, 1977, 1984, 1998 and 2009) all the experimental plots will be selected. After this procedure, the three study areas will be composed by experimental plots of these classes: a) Lands with natural vegetation since 1956. b) Abandoned lands between 1956 and 1977. c) Abandoned lands between 1977 and 1984. d) Abandoned lands between 1984 and 1998. e) Abandoned lands between 1998 and 2005. f) Cultivated lands since 1956. The main expected outcomes of the research project are the characterization of the temporal evolution of SOC in soils, the compilation of experimental areas under different Mediterranean climatic conditions, and the characterization

Miocene shale tectonics in the Moroccan margin (Alboran Sea)

Science.gov (United States)

Do Couto, D.; El Abbassi, M.; Ammar, A.; Gorini, C.; Estrada, F.; Letouzey, J.; Smit, J.; Jolivet, L.; Jabour, H.

2011-12-01

The Betic (Southern Spain) and Rif (Morocco) mountains form an arcuate belt that represents the westernmost termination of the peri-mediterranean Alpine mountain chain. The Miocene Alboran Basin and its subbasins is located in the hinterland of the Betic-Rif belt. It is considered to be a back-arc basin that developed during the coeval westward motion of the Alboran domain and the extensional collapse of previously thickened crust of the Betic-Rif belt. The Western Alboran Basin (WAB) is the major sedimentary depocenter with a sediment thickness in excess of 10 km, it is bordered by the Gibraltar arc, the volcanic Djibouti mounts and the Alboran ridge. Part of the WAB is affected by shale tectonics and associated mud volcanism. High-quality 2D seismic profiles acquired on the Moroccan margin of the Alboran Basin during the last decade reveal the multiple history of the basin. This study deals with the analysis of a number of these seismic profiles that are located along and orthogonal to the Moroccan margin. Seismic stratigraphy is calibrated from industrial wells. We focus on the interactions between the gravity-driven tectonic processes and the sedimentation in the basin. Our seismic interpretation confirms that the formation of the WAB began in the Early Miocene (Aquitanian - Burdigalian). The fast subsidence of the basin floor coeval to massive sedimentation induced the undercompaction of early miocene shales during their deposition. Downslope migration of these fine-grained sediments initiated during the deposition of the Langhian siliciclastics. This gravity-driven system was accompanied by continuous basement subsidence and induced disharmonic deformation in Mid Miocene units (i.e. not related to basement deformation). The development of shale-cored anticlines and thrusts in the deep basin is the result of compressive deformation at the front of the gravity-driven system and lasted for ca. 15 Ma. The compressive front has been re-activated by strong

Multi-decadal Variability of the Wind Power Output

Science.gov (United States)

Kirchner Bossi, Nicolas; García-Herrera, Ricardo; Prieto, Luis; Trigo, Ricardo M.

2014-05-01

The knowledge of the long-term wind power variability is essential to provide a realistic outlook on the power output during the lifetime of a planned wind power project. In this work, the Power Output (Po) of a market wind turbine is simulated with a daily resolution for the period 1871-2009 at two different locations in Spain, one at the Central Iberian Plateau and another at the Gibraltar Strait Area. This is attained through a statistical downscaling of the daily wind conditions. It implements a Greedy Algorithm as classificator of a geostrophic-based wind predictor, which is derived by considering the SLP daily field from the 56 ensemble members of the longest homogeneous reanalysis available (20CR, 1871-2009). For calibration and validation purposes we use 10 years of wind observations (the predictand) at both sites. As a result, a series of 139 annual wind speed Probability Density Functions (PDF) are obtained, with a good performance in terms of wind speed uncertainty reduction (average daily wind speed MAE=1.48 m/s). The obtained centennial series allow to investigate the multi-decadal variability of wind power from different points of view. Significant periodicities around the 25-yr frequency band, as well as long-term linear trends are detected at both locations. In addition, a negative correlation is found between annual Po at both locations, evidencing the differences in the dynamical mechanisms ruling them (and possible complementary behavior). Furthermore, the impact that the three leading large-scale circulation patterns over Iberia (NAO, EA and SCAND) exert over wind power output is evaluated. Results show distinct (and non-stationary) couplings to these forcings depending on the geographical position and season or month. Moreover, significant non-stationary correlations are observed with the slow varying Atlantic Multidecadal Oscillation (AMO) index for both case studies. Finally, an empirical relationship is explored between the annual Po and the

Cenozoic tectonic and climatic events in southern Iberian Peninsula: Implications for the evolutionary history of freshwater fish of the genus Squalius (Actinopterygii, Cyprinidae).

Science.gov (United States)

Perea, Silvia; Cobo-Simon, Marta; Doadrio, Ignacio

2016-04-01

earlier and related to the rising of the Betic Mountains. Divergence of its Atlantic and Mediterranean populations was associated with the creation of the freshwater systems of southern Iberia close to the Gibraltar Strait. The presence of S. pyrenaicus in southern Iberia may be the result of recent colonization associated with river capture, as demonstrated our biogeographic reconstruction. Copyright © 2016 Elsevier Inc. All rights reserved.

How Does Mediterranean Basin's Atmosphere Become Weak Moisture Source During Negative Phase of NAO: Use of AIRS, AMSR, TOVS, & TRMM Satellite Datasets Over Last Two NAO Cycles to Examine Governing Controls on E-P

Science.gov (United States)

Smith, Eric A.; Mehta, Amita V.

2008-01-01

annually recurring basis, and (4) investigating how such conditions might modify important internal and external climatic processes known to be closely related to the dynamical, thermal, and hydrological properties of the basin (e.g., drought frequency over Iberian peninsula, rainfall accumulation within Sahel, alteration of Levantine branch of east-west aligned open thermohaline cell, and modification of warm-salty intermediate flow through Gibraltar straight into North Atlantic).

The biodiversity of the Mediterranean Sea: estimates, patterns, and threats.

Directory of Open Access Journals (Sweden)

Marta Coll

, the Strait of Gibraltar and the adjacent Alboran Sea, western African coast, the Adriatic, and the Aegean Sea, which show high concentrations of endangered, threatened, or vulnerable species. The Levantine Basin, severely impacted by the invasion of species, is endangered as well. This abstract has been translated to other languages (File S1.

The Intersection between the Gloria Transform Fault and the Tore-Madeira Rise in the NE Atlantic: New Tectonic Insights from Analog Modeling Results

Science.gov (United States)

Rosas, F. M.; Tomas, R.; Duarte, J. C.; Schellart, W. P.; Terrinha, P.

2014-12-01

The intersection between the Gloria Fault (GF) and the Tore-Madeira rise (TMR) in NE Atlantic marks a transition from a discrete to a diffuse nature along a critical segment of the Eurasia/Africa plate boundary. To the West of such intersection, approximately since the Azores triple junction, this plate boundary is mostly characterized by a set of closely aligned and continuous strike-slip faults that make up the narrow active dextral transcurrent system of the GF (with high magnitude M>7 historical earthquakes). While intersecting the TMR the closely E-W trending trace of the GF system is slightly deflected (changing to WNW-ESE), and splays into several fault branches that often coincide with aligned (TMR related?) active volcanic plugs. The segment of the plate boundary between the TMR and the Gorringe Bank (further to the East) corresponds to a more complex (less discrete) tectonic configuration, within which the tectonic connection between the Gloria Fault and another major dextral transcurrent system (the so called SWIM system) occurs. This SWIM fault system has been described to extend even further to the East (almost until the Straits of Gibraltar) across the Gulf of Cadiz domain. In this domain the relative movement between the Eurasian and the African plates is thought to be accommodated through a diffuse manner, involving large scale strain partition between a dextral transcurrent fault-system (the SWIM system), and a set of active west-directed én-échelon major thrusts extending to the North along the SW Iberian margin. We present new analog modeling results, in which we employed different experimental settings to address (namely) the following main questions (as a first step to gain new insight on the tectonic evolution of the TRM-GF critical intersection area): Could the observed morphotectonic configuration of such intersection be simply caused by a bathymetric anomaly determined by a postulated thickened oceanic crust, or is it more compatible with

The Alboran volcanic arc archipelago isolated the Mediterranean during the Messinian salinity crisis forming the land bridge for biota dispersal across the western Mediterranean

Science.gov (United States)

Booth-Rea, Guillermo; Ranero, Cesar R.; Grevemeyer, Ingo

2017-04-01

The Mediterranean Sea desiccation during isolation from the world oceans created the well-known Messinian salinity crisis but also landbridges that permitted the exchange of terrestrial biota between Africa and Iberia contributing to the present biodiversity of the Mediterranean region. The hypotheses for the cause chocking the Mediterranean have typically sought to explain geological features, particularly the giant salt deposits, but the implications of the faunal changes occurring around that time remain inadequately integrated by current geological models. We present wide-angle seismic data that constrain for the first time the 16-18 km thick crust structure of a volcanic arc formed mostly between 10 to 6 Ma across the eastern region of the Alboran basin. The crustal structure supports that the arc created an archipelago forming a land bridge across the basin that largely isolated the Mediterranean. After the cessation of volcanic activity, the archipelago progressively submerged by thermal subsidence and accompanying sediment loading, having emerged islands that persisted into the Pleistocene time and shallow straits forming sills during the early Pliocene. The presence of an archipelago in the eastern region of the basin may explain a number of puzzling observations previously inexplicable by the proposed barriers closing the Gibraltar arc west of Alboran. The progressive volcanic build up of the archipelago together with the closure of the Betic and Rifean marine corridors would explain the initial isolation of the Mediterranean since 7.1 Ma and the exchange of terrestrial biota since 6.2 Ma, i.e. before desiccation, which diversified radiating from SE Iberia and the opposite segment of the eastern Rif. In addition, an eastern barrier agrees with the continuous Messinian-age open marine sediments drilled at ODP site 976 in the western Alboran basin, which may have been the refuge of typical Mediterranean taxa that rapidly repopulated the Mediterranean in the

The biodiversity of the Mediterranean Sea: estimates, patterns, and threats.

Science.gov (United States)

Coll, Marta; Piroddi, Chiara; Steenbeek, Jeroen; Kaschner, Kristin; Ben Rais Lasram, Frida; Aguzzi, Jacopo; Ballesteros, Enric; Bianchi, Carlo Nike; Corbera, Jordi; Dailianis, Thanos; Danovaro, Roberto; Estrada, Marta; Froglia, Carlo; Galil, Bella S; Gasol, Josep M; Gertwagen, Ruthy; Gil, João; Guilhaumon, François; Kesner-Reyes, Kathleen; Kitsos, Miltiadis-Spyridon; Koukouras, Athanasios; Lampadariou, Nikolaos; Laxamana, Elijah; López-Fé de la Cuadra, Carlos M; Lotze, Heike K; Martin, Daniel; Mouillot, David; Oro, Daniel; Raicevich, Sasa; Rius-Barile, Josephine; Saiz-Salinas, Jose Ignacio; San Vicente, Carles; Somot, Samuel; Templado, José; Turon, Xavier; Vafidis, Dimitris; Villanueva, Roger; Voultsiadou, Eleni

2010-08-02

Gibraltar and the adjacent Alboran Sea), western African coast, the Adriatic, and the Aegean Sea, which show high concentrations of endangered, threatened, or vulnerable species. The Levantine Basin, severely impacted by the invasion of species, is endangered as well. This abstract has been translated to other languages (File S1).

Contribution of the climatic transect approach application to the study of soil degradation in South of Spain.

Science.gov (United States)

Ruiz-Sinoga, José D.; Gabarrón-Galeote, Miguel A.; Cerdà, Artemi; Martínez-Murillo, Juan F.

2014-05-01

Since 1990s, the climatic transect approach has been widely applied to Mediterranean mountainous areas where climatic conditions are modified in few kilometres, from semiarid to humid conditions. The target in most of the cases was to evaluate the climatic change effect on the spatial variability of eco-geomorphological system, runoff and erosion and soil degradation processes, especially, in abandoned fields and Mediterranean rangeland. The Physical Geography and Land Management Research Group from the University of Málaga is applying this experimental approach since 2001. The study area corresponded to the Mediterranean Cordillera Bética in South of Spain, from the Strait of Gibraltar to Cabo de Gata, where a longitudinal climatic transect can be observed: from humid Mediterranean climate in the West (>1,500 mm/y) to nearly arid Mediterranean climate in the East (200 mm/y). More specifically, the investigations were focussed on the spatial and temporal variability of eco-geomorphological system (vegetation, soil and water relationship), runoff and erosion processes and controlling factors affecting to abandoned fields located in steep hillslopes of metamorphic and acid bedrocks (phyllites, schists and mica-schists) but differing in climatic conditions (humid, subhumid, dry and semiarid Mediterranean climate). The aim of this contribution is to share our findings and challenges from the last 13 years being some of the most important ones: i) Mediterranean summer drought homogenise the functioning of eco-geomorphological system independently of the geographical location along the climatic transect; ii) drought period affects more dramatically to humid and subhumid Mediterranean areas, especially, to the vegetation cover and pattern; iii) areas characterised by dry-Mediterranean climate are found as threshold areas and in risk of aridification due to Climate Change; iv) runoff and erosion processes can be similar in humid and semiarid abandoned lands as it has to

A middle Pleistocene eastern Mediterranean fish refuge: the Tsampika Bay (Rhodes, Greece)

Science.gov (United States)

Agiadi, K.; Koskeridou, E.; Moissette, P.; Lopez-Otalvaro, G. E.; Quillévéré, F.; Cornée, J. J.

2012-04-01

Extensive sampling of the Tsampika marly diatomites reveals the presence of at least three very important fish species, Bregmaceros sp., Sygnathus acus and Spratteloides sp.. Previous records of Bregmaceros sp. in the Mediterranean have suggested that this characteristic Pliocene warm-water circumglobal pelagic fish disappeared from the Mediterranean basin due to the climatic deterioration, after the Gelasian age1,2,3,4. The Tsampika fish-bearing deposits, mainly marly diatomites, are younger than 268 Ka, based on the occurrence of Emiliania huxleyi. Consequently, this is so far the youngest record of Bregmaceros sp. in the Mediterranean, suggesting that typical Pliocene fish may have found refuge in selected localities, such as Tsampika Bay, at least until the Ionian. Evidence for its presence in the Mediterranean basin today is ambiguous. Isolated records of Bregmaceros atlanticus place it in the Sicily Strait5, and off the Israeli and south Turkish coasts6. Although it appears more likely that Bregmaceros atlanticus has been introduced to the modern Mediterranean from the Red Sea, through the Suez Canal, the possibility that it is part of a small population native to the Mediterranean can not be excluded based on present-day data6. Indeed the late Pleistocene Mediterranean fish record is obsolete, due to the lack of appropriate sampling on this subject. Furthermore, the majority of Pleistocene Bregmaceros samples pertain to otoliths, which cannot be unambiguously identified on the species level. As a result, the present findings pose the considerable possibility that the Pleistocene Bregmaceros records belong to two species, B. albyi, the well known post-Messinian Mediterranean fish, and B. atlanticus, which may have invaded the Mediterranean Sea from Gibraltar along with several other warm-water taxa during recurring interglacial periods. The specific identification of the Tsampika fish will undoubtedly shed light to this possibility, and enhance our knowledge

Hourly to Decadal variability of sea surface carbon parameters in the north western Mediteranean Sea

Science.gov (United States)

Boutin, Jacqueline; Merlivat, Liliane; Antoine, David; Beaumont, Laurence; Golbol, Melek; Velluci, Vincenzo

2017-04-01

Sea surface CO2 fugacity, fCO2, is recorded hourly in the north western Mediterranean Sea since 2013 by two CARIOCA (Carbon Interface Ocean Atmosphere) sensors installed on the BOUSSOLE (Buoy for the acquisition of long term optical time series, http://www.obs-vlfr.fr/Boussole/html/project/introduction.php) mooring at 3m and 10m depth. fCO2 exhibits a large seasonal cycle, about 150 microatm peak to peak, very consistent with earlier CARIOCA measurements taken in 1995-1999 at the DYFAMED site (located 6km apart from the BOUSSOLE mooring) (Hood and Merlivat, JMR, 2001; Copin-Montegut et al., Mar. Chem., 2004): this seasonal cycle is driven primarily by intense mixing in Winter, biological uptake during Spring and warming during Summer. Interannual variability of these processes leads to interannual variability of monthly mean fCO2 that can reach more than 20 microatm. The short term variability (1 hour to 1 week) is large, especially during Summer 2014 (more than 40 microatm) due to a very strong vertical stratification and to the influence of internal waves. The hourly CARIOCA measurements allow to correctly filter out the high frequency variability while the three year long time series allow to smooth out interannual variability. Hence, for the first time, we get a precise estimate of the change of fCO2 in surface waters within 20 years. Over the 1995-2015 interval, we estimate an increase of fCO2 computed at a constant temperature of 13˚ C equal to 1.8 microatm per year. Given the alkalinity/salinity relationship in this region, we estimate mean annual rates of change of -0.0023+/-0.0001 pH unit and of +1.47+/-0.03 μmol kg-1 for pH and DIC respectively. These results give a quantitative estimate of the penetration of anthropogenic carbon in the surface waters of the northwestern Mediterranean Sea, about 80% via air-sea exchange and 20% via transport of carbon from the Atlantic across the Strait of Gibraltar as suggested by Palmieri et al (BG, 2015). We estimate

Actualización del Modelo de Cuidados de Enfermería de Virginia Henderson y su Aplicación al Estudio de las Necesidades Básicas de la Población del Campo de Gibraltar

OpenAIRE

González Rodríguez, Rafael

2015-01-01

Los principios filosóficos y científicos que fundamentan los modelos de enfermería proveen una orientación sobre cómo interpretar el fenómeno de interés de la disciplina, “el cuidado”, y cómo asumir el liderazgo del cuidado desde un marco de referencia que lo centre en aquellos aspectos fundamentales del mismo. Las construcciones teóricas y los modelos de enfermería han proporcionado la base fundamental para el progreso de la enfermería, facilitando la conceptualización de las acciones de...

Chemical tracers of shipping emissions in a Mediterranean harbour

Science.gov (United States)

Viana, M.; Amato, F.; Alastuey, A.; Querol, X.; Román, A.; García, M.

2009-04-01

Particle emissions from transport-related activities are known as one of the most important sources contributing to the PM mass concentrations in urban environments. However, only limited information is currently available in the literature on the contribution to PM levels by specific transport related sources such as shipping emissions, even though according to the latest IPCC report (Ribeiro et al., 2007), shipping emissions are receiving increased scrutiny by international and regional regulatory agencies because of their potential impact on air quality and human health in communities downwind from major shipping lanes and ports (Dominguez et al., 2008). One of the main reasons for this lack of information is the complexity in the detection of shipping emissions, given that no specific emission tracers have so far been identified as a consequence of the vast variability of combustion fuels burnt by vessels. The city of Melilla was selected for the study of shipping emissions due to its location on the South-Western sector of the Mediterranean basin, on the Northern coast of Morocco and less than 200 km from the Gibraltar Strait (35°17´40" N, 2°56´30" W). The city covers an extension of 13.4 km2, with a population of 70000 inhabitants. The monitoring station selected for the present study is representative of urban background levels, and it is located at approximately 150 m from the Melilla harbour. The harbour is mainly characterised by commercial traffic (passanger and container), although minerals and other loose materials are also stocked on the docks located farthest away from the monitoring site. PM10, PM2.5 and PM1 levels were determined on an hourly basis between 12/01/2008 and 19/12/2008 using a GRIMM laser spectrometer, which produced more than 8000 data points for each size fraction (24000 data points in total). In addition, PM10 and PM2.5 levels were sampled on quartz fibre filter substrates (Munktell) by means of high-volume samplers (PM1025 MCV

Los otros noruegos de Caneliñas: la campaña ballenera de 1929

Directory of Open Access Journals (Sweden)

Valdés Hansen, Felipe

2015-12-01

Full Text Available A previously unknown document from the Compañía Ballenera Española (Spanish Whaling Company, ceded to the author of this article, reveals new facts about the Norwegian whalers´ activity in Galicia in the 20th. century. Therefore an updating of what we know about their activity at the Caneliñas factory becomes unavoidable. This activity was interrupted in the year 1927 due to the decreasing number of captures, especially in the Straits of Gibraltar, with a decrease in the Company´s benefits and an increase in production costs, and the interest shown by the Norwegian management to relocate their activity in the Antarctic area. The 1928 failure on the part of the International Whaling Company to keep the factory open sealed the short term destiny of the Caneliñas factory. However, in 1929 the factory was briefly reopened again for a short period, when the newly acquired fleet that same year by S. Foyn Bruun and A. von der Lippe anchored there before joining their new floating factory, the Pontos, in their course to the Antarctic Ocean. This new documental source –the salaries register of CBE for the year 1929– provides a most valuable and previously unavailable information such as the work organization, a list of the company´s payroll, specifying salaries and production and capture bonuses, and many other facts. These are «he other Norwegian whalers», of whom nothing was known up to this moment, as the present article is going to show.El préstamo al autor de un documento inédito de la Compañía Ballenera Española, el libro de salarios de 1929, ha revelado nuevos datos sobre la actividad de los balleneros noruegos en Galicia en el siglo XX. Ello exige actualizar lo que sabíamos sobre su presencia en la factoría de Caneliñas, donde interrumpieron la actividad en 1927 ante la disminución de capturas (sobre todo en el estrecho de Gibraltar, la consiguiente caída de los beneficios y el aumento de los costos de explotación; adem

Late Neogene benthic stable isotope record of ODP Site 999: Implications for Caribbean paleoceanography, organic carbon burial and the Messininian salinity crisis

Science.gov (United States)

Bickert, T.; Haug, G.; Tiedemann, R.

2003-04-01

The late Neogene closure of the seaway between the North and South American continents is thought to have caused extensive changes in ocean circulation and Northern Hemisphere climate. The timing and consequences of the emergence of the Isthmus of Panama for the ocean circulation have been addressed in several papers which indicate a marked reorganization of surface and deep ocean circulation starting 4.6 million years ago. However, the biogeographic development of marine faunas and floras on both sides of the Panama Isthmus suggests that the paleoceanographic changes related to the closing of the isthmus started much earlier. Furthermore, the closing history of the Panama Seaway overlaps with the tectonic evolution of other ocean gateways in the late Miocene, especially the closure of the Strait of Gibraltar, which led to a transient isolation of the Mediterranean Sea from the Atlantic Ocean, known as the Messinian Salinity Crisis. We report on epibenthic foraminiferal d18O and d13C and percentage sand records of the carbonate fraction from Caribbean ODP Site 999 (12°44´N, 78° 44´W, water depth 2828 m) spanning the interval from 8.6 to 5.3 Ma. Low epibenthic d13C values and low sand contents indicate a poorly ventilated deep Caribbean throughout the late Miocene. At this time the deep Caribbean was dominated by a nutrient-rich Southern Ocean water mass. A mostly constant d13C gradient between the Caribbean and deep Atlantic records suggests that the fluctuations in d13C reflect rather global changes in d13C of the dissolved inorganic carbon due to varying erosion of organic carbon from terrigenous soils and shelf sediments. The observed 100-ky cyclicity of epibenthic d13C is in well accordance with the variability of the terrigenous input to the equatorial Atlantic as recorded by susceptibility records of the Ceara Rise. However, some gradient changes between 6.8 and 5.6 Ma indicate a poorer ventilation of the deep Atlantic related to a reduced production of

Coccolith concentrations in the Gulf of Cadiz at the IODP Site U1390 (Exp 339), in the last ~20,000 years

Science.gov (United States)

Angulo, M.; Balestra, B.

2013-12-01

Our project is dedicated to the study of sediment samples gathered from the Gulf of Cadiz during the Integrated Ocean Drilling Project (IODP), Expedition 339 at Site U1390. The Gulf of Cadiz is an area of the Atlantic Ocean located directly south of Portugal and the western end of the Strait of Gibraltar. We analyzed the sediment samples to obtain the numbers of coccoliths per gram of sediment in each sample. Coccolithophores (from which the coccoliths are the fossils that remain in the sediments) are one of the most abundant groups of living phytoplankton and they are significant components of marine sediment. In order to prepare our samples for counting (the process by which we determined the number of coccoliths in our samples) we utilized about 23 samples from the uppermost 17 meters of the sediment core. This process involved collecting subsamples of each individual sample and then oven drying them. Then we weighted them by utilizing a microbalance to collect the desired amount of sample we needed (between 2 and 4 mg). Several of our samples were slightly below and above this desired amount due to human error. Once we gathered the desired amount of samples for our project, we proceeded to use a filtration system to obtain filters. Then we put the filters into an oven to dry them. After the samples were dried over the course of a day, we proceeded to prepare them for viewing through the microscope. To do this, we cut the filter and placed it upon a microscope slide. Then, we applied oil to the slide, cover and placed it under the Light Microscope (LM). We looked at five different views in each filters under the microscope, counting the number of coccoliths in each view. The counting has been expressed in terms of numbers of coccoliths per gram of sediment (total coccolith concentration). Our results showed us that the amount of coccoliths in the sediment samples receded during the cold periods of time, such as an ice age, and fluctuated in an upward pattern as

Unraveling African plate structure from elevation, geoid and geology data

Science.gov (United States)

Chardon, Dominique; Bajolet, Flora; Robert, Alexandra; Rouby, Delphine

2014-05-01

) compared to tomographic models and considering the age of most geological provinces. As for the crust, the thinnest lithosphere is located in areas of Cretaceous-Jurassic rifting. References: Fullea J., Fernàndez M., Zeyen H., Vergés J., 2007. A rapid method to map the crustal and lithospheric thickness using elevation, geoid anomaly and thermal analysis. Application to the Gibraltar Arc System, Atlas Mountains and adjacent zones. Tectonophysics 430, 97-117.

Development of a Work Climate Scale in Emergency Health Services.

Science.gov (United States)

Sanduvete-Chaves, Susana; Lozano-Lozano, José A; Chacón-Moscoso, Salvador; Holgado-Tello, Francisco P

2018-01-01

An adequate work climate fosters productivity in organizations and increases employee satisfaction. Workers in emergency health services (EHS) have an extremely high degree of responsibility and consequent stress. Therefore, it is essential to foster a good work climate in this context. Despite this, scales with a full study of their psychometric properties (i.e., validity evidence based on test content, internal structure and relations to other variables, and reliability) are not available to measure work climate in EHS specifically. For this reason, our objective was to develop a scale to measure the quality of work climates in EHS. We carried out three studies. In Study 1, we used a mixed-method approach to identify the latent conceptual structure of the construct work climate . Thus, we integrated the results found in (a) a previous study, where a content analysis of seven in-depth interviews obtained from EHS professionals in two hospitals in Gibraltar Countryside County was carried out; and (b) the factor analysis of the responses given by 113 EHS professionals from these same centers to 18 items that measured the work climate in health organizations. As a result, we obtained 56 items grouped into four factors (work satisfaction, productivity/achievement of aims, interpersonal relationships, and performance at work). In Study 2, we presented validity evidence based on test content through experts' judgment. Fourteen experts from the methodology and health fields evaluated the representativeness, utility, and feasibility of each of the 56 items with respect to their factor (theoretical dimension). Forty items met the inclusion criterion, which was to obtain an Osterlind index value greater than or equal to 0.5 in the three aspects assessed. In Study 3, 201 EHS professionals from the same centers completed the resulting 40-item scale. This new instrument produced validity evidence based on the internal structure in a second-order factor model with four

Development of a Work Climate Scale in Emergency Health Services

Directory of Open Access Journals (Sweden)

Susana Sanduvete-Chaves

2018-01-01

Full Text Available An adequate work climate fosters productivity in organizations and increases employee satisfaction. Workers in emergency health services (EHS have an extremely high degree of responsibility and consequent stress. Therefore, it is essential to foster a good work climate in this context. Despite this, scales with a full study of their psychometric properties (i.e., validity evidence based on test content, internal structure and relations to other variables, and reliability are not available to measure work climate in EHS specifically. For this reason, our objective was to develop a scale to measure the quality of work climates in EHS. We carried out three studies. In Study 1, we used a mixed-method approach to identify the latent conceptual structure of the construct work climate. Thus, we integrated the results found in (a a previous study, where a content analysis of seven in-depth interviews obtained from EHS professionals in two hospitals in Gibraltar Countryside County was carried out; and (b the factor analysis of the responses given by 113 EHS professionals from these same centers to 18 items that measured the work climate in health organizations. As a result, we obtained 56 items grouped into four factors (work satisfaction, productivity/achievement of aims, interpersonal relationships, and performance at work. In Study 2, we presented validity evidence based on test content through experts' judgment. Fourteen experts from the methodology and health fields evaluated the representativeness, utility, and feasibility of each of the 56 items with respect to their factor (theoretical dimension. Forty items met the inclusion criterion, which was to obtain an Osterlind index value greater than or equal to 0.5 in the three aspects assessed. In Study 3, 201 EHS professionals from the same centers completed the resulting 40-item scale. This new instrument produced validity evidence based on the internal structure in a second-order factor model with

Operational skill assessment of the IBI-MFC Ocean Forecasting System within the frame of the CMEMS.

Science.gov (United States)

Lorente Jimenez, Pablo; Garcia-Sotillo, Marcos; Amo-Balandron, Arancha; Aznar Lecocq, Roland; Perez Gomez, Begoña; Levier, Bruno; Alvarez-Fanjul, Enrique

2016-04-01

Since operational ocean forecasting systems (OOFSs) are increasingly used as tools to support high-stakes decision-making for coastal management, a rigorous skill assessment of model performance becomes essential. In this context, the IBI-MFC (Iberia-Biscay-Ireland Monitoring & Forecasting Centre) has been providing daily ocean model estimates and forecasts for the IBI regional seas since 2011, first in the frame of MyOcean projects and later as part of the Copernicus Marine Environment Monitoring Service (CMEMS). A comprehensive web validation tool named NARVAL (North Atlantic Regional VALidation) has been developed to routinely monitor IBI performance and to evaluate model's veracity and prognostic capabilities. Three-dimensional comparisons are carried out on a different time basis ('online mode' - daily verifications - and 'delayed mode' - for longer time periods -) using a broad variety of in-situ (buoys, tide-gauges, ARGO-floats, drifters and gliders) and remote-sensing (satellite and HF radars) observational sources as reference fields to validate against the NEMO model solution. Product quality indicators and meaningful skill metrics are automatically computed not only averaged over the entire IBI domain but also over specific sub-regions of particular interest from a user perspective (i.e. coastal or shelf areas) in order to determine IBI spatial and temporal uncertainty levels. A complementary aspect of NARVAL web tool is the intercomparison of different CMEMS forecast model solutions in overlapping areas. Noticeable efforts are in progress in order to quantitatively assess the quality and consistency of nested system outputs by setting up specific intercomparison exercises on different temporal and spatial scales, encompassing global configurations (CMEMS Global system), regional applications (NWS and MED ones) and local high-resolution coastal models (i.e. the PdE SAMPA system in the Gibraltar Strait). NARVAL constitutes a powerful approach to increase

Oceanographic and surface meteorological data collected from Gibraltar Island Station by Ohio State University; Stone Laboratory and assembled by Great Lakes Observing System (GLOS) in the Great Lakes region from 2015-05-26 to 2017-08-31 (NCEI Accession 0130545)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0130545 contains oceanographic and surface meteorological data in netCDF formatted files, which follow the Climate and Forecast metadata convention...

pH, alkalinity, temperature, salinity and other variables collected from profile observations using Alkalinity titrator, CTD and other instruments from the HESPERIDES in the North Atlantic Ocean and Strait of Gibraltar from 2008-10-06 to 2008-10-12 (NODC Accession 0112927)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112927 includes chemical, discrete sample, physical and time series profile data collected from HESPERIDES in the North Atlantic Ocean and Strait of...

Physical, chemical and biological observations and modeling of oil spills in the Mediterranean Sea

Science.gov (United States)

Ribotti, A.; De Dominicis, M.

2016-11-01

such actions. Illegal discharges of oil from ships are often limited in size and scattered but, surprisingly, their sum is higher than that from oil spills, and they may create a chronic impact of oil in certain areas. For instance littoral sediments affected by low or moderated but continuous oil spills, like the coasts of the Bay of Algeciras (near the Strait of Gibraltar), are more polluted than those affected by accidental oil spills such as during the Prestige accident (2002) (Morales-Caselles et al., 2007). Oil discharges may be also accidental. According to the International Tanker Owners Pollution Federation Ltd (ITOPF) a lot of pollutions are due to a combination of factors that lead to groundings, collisions, structural failures, fires and explosions.

Crustal deformation pattern of the Morocco-Iberian area: constraints from 14 years of GPS measurements

Science.gov (United States)

Palano, Mimmo; González, Pablo; Fernandez, Josè

2014-05-01

associated covariance information we derived a continuous velocity gradient tensor on a regular 0.35° x 0.35° grid using a "spline in tension" technique. The velocity field was interpolated by removing from the computation all sites with fewer than 2.5 years of data and/or because of their suspicious movements with respect to nearby sites. Geodetic data reveals that appreciable deformation occurs prevailing along the W and SE margins of the Iberian Peninsula (up to 35 nanostrain/yr) and along the Gibraltar arc (up to 90 nanostrain/yr), while on the inner parts of the peninsula, the crustal deformation occurs locally at rate < 15 nanostrain/yr. Finally, we compared our findings with the regional frame illustrated by geological and seismological data published in literature. In addition, we statistically tested our GPS velocity field solution on a possible independent motion of the Iberian Peninsula with respect the Eurasian plate.

Vulnerability of marginal seas to sea level rise

Science.gov (United States)

Gomis, Damia; Jordà, Gabriel

2017-04-01

Sea level rise (SLR) is a serious thread for coastal areas and has a potential negative impact on society and economy. SLR can lead for instance to land loss, beach reduction, increase of the damage of marine storms on coastal infrastructures and to the salinization of underground water streams. It is well acknowledged that future SLR will be inhomogeneous across the globe, with regional differences of up to 100% with respect to global mean sea level (GMSL). Several studies have addressed the projections of SLR at regional scale, but most of them are based on global climate models (GCMs) that have a relatively coarse spatial resolution (>1°). In marginal seas this has proven to be a strong limitation, as their particular configurations require spatial resolutions that are not reachable by present GCMs. A paradigmatic case is the Mediterranean Sea, connected to the global ocean through the Strait of Gibraltar, a narrow passage of 14 km width. The functioning of the Mediterranean Sea involves a variety of processes including an overturning circulation, small-scale convection and a rich mesoscale field. Moreover, the long-term evolution of Mediterranean sea level has been significantly different from the global mean during the last decades. The observations of present climate and the projections for the next decades have lead some authors to hypothesize that the particular characteristics of the basin could allow Mediterranean mean sea level to evolve differently from the global mean. Assessing this point is essential to undertake proper adaptation strategies for the largely populated Mediterranean coastal areas. In this work we apply a new approach that combines regional and global projections to analyse future SLR. In a first step we focus on the quantification of the expected departures of future Mediterranean sea level from GMSL evolution and on the contribution of different processes to these departures. As a result we find that, in spite of its particularities

The influence of tide-topography interaction on low-frequency heat and nutrient fluxes. Application to Cape Trafalgar

Science.gov (United States)

Vargas-Yáñez, Manuel; Viola, Tarek Sarhan; Jorge, Francisco Plaza; Rubín, Juan P.; García-Martínez, M. Carmen

2002-01-01

During July 1994, 1995 and 1996, the Instituto Español de Oceanografía carried out three multidisciplinar surveys in the Northwestern Alboran Sea, Strait of Gibraltar and Gulf of Cadiz. Conductivity-temperature-depth (CTD) data and nutrient measurements revealed the existence of a pool of cool surface waters, rich in nutrients and with high fluorescence values offshore Cape Trafalgar during the three surveys. These data are considered as an indication of some sort of upwelling. The presence of a submarine ridge, breaking the continental shelf off Trafalgar and intercepting along shore tidal currents, and the intense winds in this area make us think that tide-topography interaction, probably enhanced by wind stirring in surface layers, is responsible for this phenomenon. Its permanence is inspected by means of the sea surface temperature (SST) satellite images recompiled for one year. They show that the pool is very frequent in summer and autumn, more unusual in spring and exceptional in winter. The explanation considered is that the mixing of deep and surface waters is only an effective means of heat exchange when the water column is stratified. To support our initial hypothesis and to get some insight of the relevant factors involved, we develop a bidimensional model aimed at studying along shore variations on the temperature, nutrient and chlorophyll distributions. Although the physical-biological model is very simple, it is able to show how large vertical excursions due to tide-topography interaction produce an eddy flux of heat and nutrients, cooling and fertilising areas around the topographic accident. The model is initialised with along-shore homogeneous distributions of all the variables modelled to check if the mechanism proposed is able to break this homogeneity in a similar way to the observed in experimental data. Appreciable differences between areas affected by tide-topography interaction and those far away from it appear in several days, a time

Evolución biogeográfica de los Pachydeminae paleárticos (Coleoptera, Scarabaeoidea mediante análisis de dispersión-vicarianza

Directory of Open Access Journals (Sweden)

Sanmartín, Isabel

2003-12-01

consecutive dispersal barriers (e.g., the Red Sea, the Zagros Mountains. This geographic division was followed by fragmentation (vicariance of the ancestral biota, giving rise to several disjunct genera (Pachydema Castelnau, 1832, Hemictenius Reitter, 1897. The Middle East region and the Iranian Plateau acted as centers of diversification during the evolution of the subfamily: many of the least speciose genera of Pachydeminae originated within these two regions by sympatric speciation (Otoclinius Brenske, 1896. In contrast, the presence of Pachydeminae in the Western Mediterranean region (Iberian Peninsula and southwestern Mediterranean Islands is the result of a more recent dispersal event. The ancestor of the Iberian genera Ceramida Baraud, 1987 and Elaphocera Gené, 1836 probably dispersed from the Middle East to the Iberian Peninsula across North Africa and the Gibraltar Strait. This dispersal could have taken place during the “Messinian salinity crisis” at the end of the Miocene, when the Red Sea and the Mediterranean partially dried-up, allowing a short period of biotic dispersal between West Asia, North Africa, and the Iberian Peninsula. The subsequent evolution of Ceramida and Elaphocera seem to have involved repeated vicariance events between the East and West Mediterranean, and between the Iberian Peninsula and North Africa. In the Iberian Peninsula, the two genera are geographically segregated: most species of Ceramida are found in the southwestern region, whereas Elaphocera is generally restricted to the southeastern Iberian Peninsula.

En este trabajo, se reconstruye la historia biogeográfica de la subfamilia Pachydeminae Reitter, 1902 (Coleoptera, Scarabaeoidea, Melolonthidae en el Paleártico occidental, utilizando el análisis de dispersión-vicarianza (DIVA. Este método de análisis biogeográfico reconstruye las distribuciones ancestrales en la filogenia de acuerdo con un simple

pH, alkalinity, temperature, salinity and other variables collected from time series profile observations using Alkalinity titrator, CTD and other instruments from the Al Amir Moulay Abdellah in the North Atlantic Ocean and Strait of Gibraltar from 2005-05-04 to 2007-05-08 (NODC Accession 0112928)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112928 includes chemical, discrete sample, physical and time series profile data collected from Al Amir Moulay Abdellah in the North Atlantic Ocean...

Late Miocene to present-day exhumation and uplift of the Internal Zone of the Rif chain: Insights from low temperature thermochronometry and basin analysis

Science.gov (United States)

Romagny, A.; Ph. Münch; Cornée, J.-J.; Corsini, M.; Azdimousa, A.; Melinte-Dobrinescu, M. C.; Drinia, H.; Bonno, M.; Arnaud, N.; Monié, P.; Quillévéré, F.; Ben Moussa, A.

2014-07-01

Located on the margin of the west Alboran basin, the Gibraltar Arc (Betic-Rif mountain belt) displays post-Pliocene vertical movements evidenced by uplifted marine sedimentary basins and marine terraces. Quantification of vertical movements is an important clue to understand the origin of present-day relief generation in the Betic-Rif mountain chain together with the causes of the Messinian Salinity Crisis. In this paper, we present the results of a pluridisciplinary study combining an analysis of low temperature thermochronology and Pliocene basins evolution to constrain the exhumation history and surface uplift of internals units of the Rif belt (Northern Morocco). The mean (U-Th)/He apatite ages obtained from 11 samples are comprised between 14.1 and 17.8 Ma and display a wide dispersion, which could be explained by a great variability of apatite chemistries in the analyzed samples. No correlations between altitude and age have been found along altitudinal profile suggesting a rapid exhumation during this period. Thermal modeling using our (U-Th)/He apatite ages and geochronological data previously obtained in the same area (40Ar/39Ar and K/Ar data on biotite, zircon and apatite fission track) allow us to propose a cooling history. The rocks suffered a rapid cooling at 60-100 °C/Ma between 22.5 and 19 Ma, then cooled to temperatures around 40 °C between 19 and 18 Ma. They were re-heated at around 110 °C between 18 and 15 Ma then rapidly cooled and exhumed to reach the surface temperature at around 13 Ma. The re-heating could be related to a renewal in thrusting and burying of the inner zones. Between 15 and 13 Ma the cooling resumed at a rate of 50 °C/Ma indicating an exhumation rate of 0.8 mm/y considering an average 40 °C/km geothermal gradient. This exhumation may be linked to the extension in the Alboran Sea. Otherwise biostratigraphic and sedimentological analysis of Pliocene basins of the internal Rif provided informations on the more recent events

Extensional Detachment faulting in melange rocks. Plurikilometres migration by W the External Zone (Cordillera Bética, Spain)

Science.gov (United States)

Roldán, Francisco Javier; Azañon, Jose Miguel; Rodríguez, Jose; Mateos, Rosa Maria

2014-05-01

ético durante el Mioceno medio-superior: El Complejo Extensional Subbético. Boletín Geológico y Minero, 124 (3): 477-504. Roldán, F.J., Azañón, J.M. y Rodríguez-Fernández, J. (2012): Desplazamiento extensional del Subbético entre las sierras de Cabra y Alta Coloma (Valdepeñas de Jaén. Zonas Externas de la Cordillera Bética). VIII Congreso Geológico de España oviedo. GEOTEMAS, V-13: 484. Roldán, F.J., Rodríguez-Fernández, J., Villalobos, M., Lastra, J., Díaz-Pinto, G., Pérez Rodríguez, A.B. (2012). Zonas: Subbético, Cuenca del Guadalquivir y Campo de Gibraltar. In GEODE. Mapa Geológico Digital Continuo de España. Sistema de Información Geológica Continua: SIGECO. IGME. Editor Navas, J. Disponible en: http://cuarzo.igme.es/sigeco.default.htm

Late Miocene extension partitioning in the eastern Betics: from W- to E-directed extension between the Sorbas and Vera basins (SE Spain).

Science.gov (United States)

Giaconia, Flavio; Booth-Rea, Guillermo; Martínez-Martínez, Jose Miguel; Azañon, Jose Miguel

2014-05-01

Late Miocene westward-directed extension in the Betics produced elongated core-complexes like Sierra Nevada and the Sierra de Filabres, tilted-block domains and associated basins. This extension represents the superficial manifestation of the rupture of the Tethyan slab and associated edge delamination along a lithospheric transform fault beneath the northern branch of the Gibraltar Arc orogenic system. However, crustal thinning at the eastern Betics occurs progressively towards the east suggesting an eastward-directed extension, probably related to the late Miocene opening of the Algero-Balearic basin. In order to define the kinematics and timing of such a heterogeneous extension at the eastern Betics we have carefully mapped a key area at the transition between the Sorbas and Vera basins. Field data indicate that extension in the area started at the southern margin of the Vera basin during the Serravallian (13.8 Ma) and continued until the Tortonian (approximately 8 Ma). This extension was characterized by a set of NE- to E-directed normal faults to the east, in the Vera basin, and a set of SW-directed normal faults to the west, towards the Sorbas basin. This opposite-directed extension is segmented by E-W to WNW-ESE strike-slip faults like the North Cabrera dextral transfer fault that accommodates NE- to E-directed extension to the north and SW-directed extension to the south. This structure resulted in westward tilted blocks that lead to Serravallian-Tortonian depocenters deepening towards the east at the Vera basin along the northern side of Sierra Cabrera. Meanwhile, at the western termination of Sierra Cabrera, westward-directed extension migrated SW-ward forming the Sorbas basin during the Tortonian (approximately 9-7.24 Ma). This extension was characterized by a listric fan of SW-directed normal faults highly segmented by E-W to NE-SW transfer. This extensional system produced tiled-blocks defining a Tortonian depocenter at the eastern margin of the Sorbas

pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using Alkalinity titrator, CTD and other instruments from the HESPERIDES in the North Atlantic Ocean, South Atlantic Ocean and Strait of Gibraltar from 2013-03-20 to 2013-05-22 (NODC Accession 0114434)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0114434 includes chemical, discrete sample, physical and profile data collected from HESPERIDES in the North Atlantic Ocean, South Atlantic Ocean and...

A Trip Through the Virtual Ocean: Understanding Basic Oceanic Process Using Real Data and Collaborative Learning

Science.gov (United States)

Hastings, D. W.

2012-12-01

How can we effectively teach undergraduates the fundamentals of physical, chemical and biological processes in the ocean? Understanding physical circulation and biogeochemical processes is essential, yet it can be difficult for an undergraduate to easily grasp important concepts such as using temperature and salinity as conservative tracers, nutrient distribution, ageing of water masses, and thermocline variability. Like many other topics, it is best learned not in a lecture setting, but working with real data: plotting values, making predictions, and making mistakes. Part I: Using temperature and salinity values from any location in the world ocean (World Ocean Atlas), combined with an excellent user interface (http://ferret.pmel.noaa.gov), students are asked to answer a series of specific questions related to ocean circulation. Using established temperature and salinity values to characterize different water masses, students are able to identify various water masses and gain insight to physical circulation processes. Questions related to ocean circulation include: How far south and at what depth does NADW extend into the S. Atlantic? Is deep water formed in the North Pacific? How and why does the depth of the thermocline vary with latitude in the Atlantic Ocean? How deep does the Mediterranean Water descend as it leaves the Straits of Gibraltar? How far into the Atlantic can you see the influence of the Amazon River? Is there any Antarctic Bottom Water in the North Pacific? Collaborating with another student typically leads to increased engagement. Especially in large lecture settings, where one teacher is not able to address student questions or concerns, working in pairs or in groups of three is best. Part II: Using the same web-based viewer and data set students are subsequently assigned one oceanic property (phosphate, nitrate, silicate, O2, or AOU) and asked to construct three different plots: 1) vertical depth profile at one location; 2) latitude vs. depth

The Mediterranean

Science.gov (United States)

Suryawanshi, Vandana

2017-04-01

Learning is always a joyful experience for any human being and must always remain so. Children are happiest when they learn through play. The philosophy of my life is to keep encouraging children to think beyond they could achieve easily. I understand children are adaptive to change and take things with an open mind. They are ready to experiment new things and dare to dream big. I am fortunate to be a teacher by profession and thus I always attempt experimenting, observing and participating with other children and adults. Education is not about moulding children the way you think they should be. It is about organizing the natural longing in a human being to know. From birth children are active participants in building their own understanding. I always prepare the environment to help each child build on what they already know. It is such a great pleasure to observe every young kid become excited and curious to know when we teach them. Std 8 Geography the students are very excited to learn about this continent, with the help of Videos and a wall map the Political map of Europe with its countries shown I introduced the topic by asking 'If given a chance which place they would like to visit in Europe' , students are familiar with the countries of their favourite football players and happily pointed out their destination. The Mediterranean Region is a paradise the scenic beauty, the climate, the food along with a variety of fruits which are totally different from Asia increased the curiosity among the students. With the help of case study of the Mediterranean Sea the students were able to research and present the history, the adventure sports the aquatic life and the twenty three beautiful islands located in the Mediterranean Sea. Photos and videos helped me to explain the Mediterranean Sea The Formation of the Mediterranean Sea ( Youtube Video) which is otherwise completely enclosed by land. (The evaporating Mediterranean Sea - BBC (Video) Gibraltar Breach.mov . The

From the Atlas to the Variscan Core of Iberia: Progress on the Knowledge of Mantle Anisotropy from SKS Splitting

Science.gov (United States)

Diaz Cusi, J.; Grevemeyer, I.; Thomas, C.; Harnafi, M.

2012-12-01

The data provided by the dense Iberarray broad-band seismic network deployed in the framework of the large-scale TopoIberia project, as well as from permanent broad-band stations operating in Morocco, Portugal and Spain has allowed to get a large scale view of the anisotropic properties of the mantle beneath the western termination of the Mediterranean region and its transition to the Atlantic ocean. In this contribution we will gather the previously presented results with the analysis of the data provided by IberArray stations in the central part of Iberia, broad-band OBSs deployments in the Alboran Sea and the Gulf of Cadiz and new seismic networks deployed in the High Atlas and the Moroccan Meseta. The High Atlas has been investigated using data from a broad-band network installed by the Univ. of Munster with a primary focus on the study of the properties of the deep mantle. Additionally, up to 10 Iberarray stations have been shifted southward to complete the survey along the Atlas and to investigate the Moroccan Meseta. In agreement with the results presented by the Picasso team along a profile crossing the Atlas northward, the anisotropy observed in this area is small (0.6 - 0.9 s) with a fast polarization direction (FPD) oriented roughly E-W. It is important to note that there is a very significant number of high quality events without evidence for anisotropy. This may be the result of the combined effect of two or more anisotropic layers or of the presence of a large vertical component of flow in the upper mantle. Moving northwards, the first TopoIberia-Iberarray deployment in the Betics-Alboran zone has evidenced a spectacular rotation of the FPD along the Gibraltar arc following the curvature of the Rif-Betic chain, from roughly N65E beneath the Betics to close to N65W beneath the Rif chain. To complete this image, we have now processed data from two OBS deployments in the Alboran Sea and Gulf of Cadiz installed by Geomar as part of the TopoMed project

Determination of recent horizontal crustal movements and deformations of African and Eurasian plates in western Mediterranean region using geodetic-GPS computations extended to 2006 (from 1997) related to NAFREF and AFREF frames.

Science.gov (United States)

Azzouzi, R.

2009-04-01

Determination of recent horizontal crustal movements and deformations of African and Eurasian plates in western Mediterranean region using geodetic-GPS computations extended to 2006 (from 1997) related to NAFREF and AFREF frames. By: R. Azzouzi*, M. Ettarid*, El H. Semlali*, et A. Rimi+ * Filière de Formation en Topographie Institut Agronomique et Vétérinaire Hassan II B.P. 6202 Rabat-Instituts MAROC + Département de la Physique du Globe Université Mohammed V Rabat MAROC This study focus on the use of the geodetic spatial technique GPS for geodynamic purposes generally in the Western Mediterranean area and particularly in Morocco. It aims to exploit this technique first to determine the geodetic coordinates on some western Mediterranean sites. And also this technique is used to detect and to determine movements cross the boundary line between the two African and Eurasian crustal plates on some well chosen GPS-Geodynamics sites. It will allow us also to estimate crustal dynamic parameters of tension that results. These parameters are linked to deformations of terrestrial crust in the region. They are also associated with tectonic constraints of the study area. The usefulness of repeated measurements of these elements, the estimate of displacements and the determination of their temporal rates is indisputable. Indeed, sismo-tectonique studies allow a good knowledge of the of earthquake processes, their frequency their amplitude and even of their prediction in the world in general and in Moroccan area especially. They allow also contributing to guarantee more security for all most important management projects, as projects of building great works (dams, bridges, nuclear centrals). And also as preliminary study, for the most important joint-project between Europe and Africa through the Strait of Gibraltar. For our application, 23 GPS monitoring stations under the ITRF2000 reference frame are chosen in Eurasian and African plates. The sites are located around the

The changing Mediterranean Sea — a sensitive ecosystem?

Science.gov (United States)

Turley, Carol M.

1999-08-01

I was asked to present a keynote paper on the socio-economic aspects of oceanographic research in the Mediterranean Sea in the Session on From Oceanographic Science to Policy at the International Conference on Progress in Oceanography of the Mediterranean Sea, Rome November 1997. The session was unique in that it included papers from oceanographers, social scientists and economists. For this reason I have aimed this paper towards, what I consider to be, social and economic issues that may have important oceanographic outcomes and vice versa. I have attempted to express them in a manner that can be understood by economists, social scientists, policy makers and oceanographers alike. The Mediterranean is highly populated and the greatest tourist destination in the world, both of which are predicted by UNEP to rise substantially in the future. Its blue waters, however, include some of the most extreme oligotrophic waters in the world such that it is only capable of supplying 50% of its requirements for fish. The relatively clear, pigment poor surface waters of the Mediterranean have a general increasing oligotrophy eastward with substantially lower phytoplankton, benthic and fish production in the eastern basin. The Mediterranean Sea is highly sensitive to climatic changes; it has high evaporation rates, low land runoff from few rivers and seasonal rains resulting in a deficit in its hydrological balance. This has worsened with the damming of rivers such as the Nile. Nutrient depleted Atlantic water flows into the Mediterranean through the narrow Strait of Gibraltar and exits after circulating the basin with nearly 10% more salt content. This hydrological imbalance may have far-reaching consequences in the Atlantic, producing similar climate changes in Northern Europe, to that seen during the last glaciation, and may be linked to a hydrological deficit in the Mediterranean Sea resulting from a decline in the Nile outflow. The basin-wide circulation, hot-dry and

Evidences of intraplate deformation in the West Madeira Abyssal Plain (eastern North Atlantic) from seismic reflection and multibeam swath bathymetry data

Science.gov (United States)

Roque, C.; Simões, M.; Lourenço, N.; Pinto de Abreu, M.

2009-04-01

The West Madeira Abyssal Plain is located in the eastern North Atlantic off Madeira Islands, forming part of the Canary Basin and reaching a mean water depth of 5300 m. This region is also located within Africa plate at about 500 km southwards from the Açores-Gibraltar plate boundary, and for that reason lacks seismic activity. Although this region being located in an intraplate setting, the presence of faulted sediments was reported in several works published during the eighties of last century following a study conducted in late 1970s to evaluate the feasibility of disposal of high-level radioactive wastes in the ocean. According these works, the Madeira Abyssal Plain sediments are cut by many normal growth faults and this deformation is a result of compaction and dewatering of the sediments. Evidences of tectonic deformation of oceanic sediments in intraplate settings are uncommon, but folded sediments and reverse faults extending into the basement, were recognized in the equatorial Indian Ocean and in the West African continental margin. Recently, during 2006 multi-channel seismic reflection and multibeam swath bathymetry surveys were carried out in the West Madeira Abyssal Plain by EMEPC in order to prepare the Portuguese proposal for the extension of the continental shelf. The seismic lines were acquired onboard R/V Akademik Shatskiy using a source of 5720 cu in bolt gun array, cable length of 7950 m and shot interval of 50.00 m. The multibeam swath bathymetry was acquired onboard NRP Gago Coutinho, and allowed a high resolution mapping of the main geomorphological features. The multichannel seismic lines, oriented WNW-ESE, image the Madeira island lower slope located at about 4000 m water depth and the almost flat abyssal plain at about 5300 m water depth. These seismic lines show a thick sedimentary succession that reaches a maximum thickness of about 1.5 sec twt in the deepest parts of the West Madeira Abyssal Plain, overlying an irregular diffractive

Subduction initiation and recycling of Alboran domain derived crustal components prior to the intra-crustal emplacement of mantle peridotites in the Westernmost Mediterranean: isotopic evidence from the Ronda peridotite

Science.gov (United States)

Varas-Reus, María Isabel; Garrido, Carlos J.; Bosch, Delphine; Marchesi, Claudio Claudio; Acosta-Vigil, Antonio; Hidas, Károly; Barich, Amel

2014-05-01

-Rif cordillera crustal rocks that might have been potentially subducted beneath the Alborán domain before the emplacement of Ronda peridotites. Isotopic data rules out potential crustal sources coming from pre-early Miocene Flysch Trough sediments and crustal rocks from the Blanca Unit currently underlying peridotite. Crustal rocks from the Jubrique Unit overlying the Ronda peridotite are the only crustal samples that may account for the relatively high 207Pb-208Pb/204Pb and low 206Pb/204Pb characteristic of the crustal contaminant added to the mantle source of late Cr-pyroxenites. These data strongly support Alboran geodynamic models that envisage slab roll-back as the tectonic mechanism responsible for Miocene lithospheric thinning, and provides a scenario where back-arc inversion leading to self-subduction of crustal units at the front of the Alboran wedge. REFERENCES 1. Durand-Delga, M., P. Rossi, P. Olivier, and D. Puglisi, Situation structurale et nature ophiolitique de roches basiques jurassiques associées aux flyschs maghrébins du Rif (Maroc) et de Sicile (Italie). Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science, 2000. 331(1): p. 29-38. 2. Lenoir, X., C. Garrido, J.L. Bodinier, J.M. Dautria, and F. Gervilla, The Recrystallization Front of the Ronda Peridotite: Evidence for Melting and Thermal Erosion of Subcontinental Lithospheric Mantle beneath the Alboran Basin. Journal of Petrology, 2001. 42(1): p. 141-158. 3. Garrido, C.J., F. Gueydan, G. Booth-Rea, J. Precigout, K. Hidas, J.A. Padrón-Navarta, and C. Marchesi, Garnet lherzolite and garnet-spinel mylonite in the Ronda peridotite: Vestiges of Oligocene backarc mantle lithospheric extension in the western Mediterranean. Geology, 2011. 4. Balanyá, J.C., V. García-Dueñas, J.M. Azañón, and M. Sánchez-Gómez, Alternating contractional and extensional events in the Alpujarride nappes of the Alboran Domain (Betics, Gibraltar Arc). Tectonics, 1997. 16(2): p. 226-238. 5. Platt, J

Drilling through the Messinian evaporites: the beginning of a new adventure?

Science.gov (United States)

Bassetti, M. A.; Lofi, J.

2009-04-01

The sensitivity of past environments tell us a lot about the nature of changes, either of climatic or geodynamic origin. In this respect, the Mediterranean basin represents the ideal natural laboratory for studying the interaction between deep processes, tectonics, sedimentary fluxes and sea-level oscillation that are at the origin of the sedimentary records. A spectacular example of reactivity of this system have been experienced less than 6 Myrs ago, when the pan-Mediterranean realm underwent rapid and abrupt changes of paleo-environmental parameters that led to the well known Messinian Salinity Crisis (MSC, Hsü et al., 1973). This short-term event at the geological scale (~5.96-5.32 Ma) results from the progressive closure of the two-way connection between the Atlantic Ocean and the Mediterranean Sea. The most important characteristics of this event are: (1) a reduction of the Atlantic water supply having as a consequence, an increased salinity and in the precipitation of thick evaporites within shallow water marginal basins (presently disconnected from the deep basins); (2) a subsequent major sea-level fall exceeding 2000 m and resulting in the massive erosion of the margins and the development of deep subaerial canyons; (3) the accumulation of the product of the erosion in the downslope domain of the margins; (4) the deposition of thick evaporites (up to 3000 m thick) above the deep Mediterranean abyssal plains and (5) and a very rapid refilling of the Mediterranean basin during the Latest Miocene/Lower Pliocene, following the re-connection between Atlantic and Mediterranean through the Gibraltar straight. Timing, causes and chronology of the MSC are not yet fully understood, but different scenarii have been proposed to explain in details the modalities of this catastrophic event. Certainly, the ongoing discussion about not fully conclusive interpretations are mainly linked to the fact that so far, only the deepest and buried Mediterranean basins might offer

Including cetaceans in multi-species assessment models using strandings data: why, how and what can we do about it?

Directory of Open Access Journals (Sweden)

Camilo Saavedra

2014-07-01

due to lack of good information because, unlike the case of commercial fish stocks, usually there are no timeseries of abundance estimates available and the biological information available has been derived from the examination of stranded and/or bycatch individuals which could generate biased estimates. Common dolphin is the more abundant species of small cetacean in the Atlantic coast of the Iberian Peninsula and for which more biological information is available. For this reason, we have used this species as an example to explain our approach to obtain estimates of all the biological parameters needed to build a cetacean population model from strandings data. Southern European hake stock is distributed from Gulf of Biscay to Strait of Gibraltar, along Atlantic coast of the Iberian Peninsula, and thus the common dolphin population we will try to model is the one which lies in this area, although it is considered that there is a single common dolphin population is continuous throughout the European Atlantic coast (Natoli, 2008. Due to their protected status, no timeseries of catches neither fishing biological samples exist in the area, in contrast as in commercial fish species. Therefore, the major source of biological information is derived from strandings, mainly collected by experienced personnel from the “Coordinadora para o Estudio dos Mamíferos Mariños” (CEMMA operating in Galicia (Northwest of Spain since 1990. From these data we have derived the direct and indirect information required for our model. However, only the following parameters: maximum and minimum dolphin length and weight, sex-ratio and proportion of dead dolphins exhibiting bycatch signs can be used without further data processing. From these parameters, the length-weight relationship can also be easily calculated for both males and females, in our case, by fitting a logarithmic regression. Nonetheless, to fit a growth curve is necessary to know the age of each stranded dolphin and