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Genetic diversity of the pan-European freshwater mussel Anodonta anatina (Bivalvia: Unionoida) based on CO1: new phylogenetic insights and implications for conservation

Froufe, Elsa; Sobral, Carina; Teixeira, Amílcar; Sousa, Ronaldo; Varandas, Simone; Aldridge, David; Lopes-Lima, Manuel
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
29.1716%
1. The duck mussel, Anodonta anatina, has been described as abundant and widespread in Europe. However, it is listed as near threatened or threatened in several countries owing to severe declines in abundance and/or spatial distribution. 2. Despite its potential ecological importance and conservation status almost nothing is known regarding its genetic diversity. 3. As a preliminary analysis, variation within the cytochrome oxidase 1 mitochondrial gene was determined from European specimens from Portugal in the south west, to Ukraine in the east, and Sweden in the north. 4. Three major mtDNA clades were retrieved: clade 1 includes all the individuals from Iberia, except those from the Ebro basin; clade 2 includes all the European non-Iberian and non-Italian samples; and clade 3 includes all the individuals from Italy and from the Ebro basin. AMOVA analysis revealed significant genetic differences among the three clades. Within each of the major clades, several geographically related haplogroups were also retrieved, especially in Iberia, where four genetically distinct groups (North-West, South-Central, South-West and Ebro) were revealed. 5. Given the evidence of regional declines of A. anatina in Europe, the confirmation of geographically distinct genotypes indicates a need for the development of management strategies directed towards the conservation of localized populations.

A sensory and nutritional comparison of mussels (Mytilus sp.) produced in NW Iberia and in the Armona offshore production area (Algarve, Portugal)

Oliveira, Ana R.; Sykes, António V.; Hachero-Cruzado, Ismael; Azeiteiro, Ulisses M.; Esteves, Eduardo
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
27.822295%
A biometric, nutritional and sensory analysis of raw and cooked mussels comparing Mytilus sp. from the north-west coast of Portugal and Spain (Minho and Galicia, respectively) and the new offshore production site of Armona (Algarve, south Portugal) was carried out. In addition, multiple factorial analysis was performed to explore potential relationships between sensory attributes and nutritional content properties between the different mussels. Results showed that, at similar times of sale, biometrics of mussels from Armona and Vigo were similar and bigger than the remaining. Nonetheless, despite some similarities in proximate composition, mussels presented differences in lipid classes, fatty acid content and free amino acids profiles. These differences were not fully reflected in the sensory assessment by the panel, which were able to distinguish different production sites in raw specimens but displayed problems in discrimination these in cooked mussels. Some nutritional components were related to specific sensory sensations.

Genetic diversity of the pan-european freshwater mussel Anodonta anatina (bivalvia : unionoida) based on CO1 : new phylogenetic insights and implications for conservation

Froufe, Elsa; Sobral, Carina; Teixeira, Amílcar; Sousa, Ronaldo Gomes; Varandas, Simone; Aldridge, David C.; Lima, Manuel Lopes
Fonte: John Wiley & Sons, Ltd. Publicador: John Wiley & Sons, Ltd.
Tipo: Artigo de Revista Científica
Publicado em //2014 ENG
Relevância na Pesquisa
29.1716%
1. The duck mussel, Anodonta anatina, has been described as abundant and widespread in Europe. However, it is listed as near threatened or threatened in several countries owing to severe declines in abundance and/or spatial distribution. 2. Despite its potential ecological importance and conservation status almost nothing is known regarding its genetic diversity. 3. As a preliminary analysis, variation within the cytochrome oxidase 1 mitochondrial gene was determined from European specimens from Portugal in the south west, to Ukraine in the east, and Sweden in the north. 4. Three major mtDNA clades were retrieved: clade 1 includes all the individuals from Iberia, except those from the Ebro basin; clade 2 includes all the European non-Iberian and non-Italian samples; and clade 3 includes all the individuals from Italy and from the Ebro basin. AMOVA analysis revealed significant genetic differences among the three clades. Within each of the major clades, several geographically related haplogroups were also retrieved, especially in Iberia, where four genetically distinct groups (North-West, South-Central, South-West and Ebro) were revealed. 5. Given the evidence of regional declines of A. anatina in Europe, the confirmation of geographically distinct genotypes indicates a need for the development of management strategies directed towards the conservation of localized populations

Seismicity along the Western Eurasia- Africa plate boundary

Bezzeghoud, M.
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Aula
POR
Relevância na Pesquisa
18.888683%
extends from the Azores Islands to the Strait of Gibraltar. The interaction between Iberia and Africa results in a complex region located in the western part of the Eurasian-African plate boundary. This region corresponds to the transition from an oceanic boundary, to a continental boundary where Iberia and Africa collide. The change in the seismicity along the Azores-Gibraltar-Algeria Plate boundary zone confirms that the present plate movement is transtensional in the Azores, dextral along the Gloria transform and convergent between the SW Atlantic margin and the Ibero-Maghrebian zone. The convergence rate decreases west (Azores plateau) to east (Ibero-Maghrebian zone). The plate boundary is very well delimited in the oceanic part, from the Azores Islands along the Azores-Gibraltar fault to approximately 12ºW (west of the Strait of Gibraltar). From 12ºW to 3.5ºE, including the Iberia-African region and extending to the western part of Algeria, the boundary is more diffuse and forms a wider area of deformation (Buforn et al., 2004; Borges et al., 2007; Bezzeghoud et al., 2008). This is also reflected by the occurrence of historical and instrumental large earthquakes, in particular by the recent earthquakes occurred in the Azores Islands...

A COMBINED MULTI-ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH-WEST IBERIA: SYNCHROTRON m-XRF, EXTERNAL-PIXE/PIGE AND BSEM–EDS

Carneiro, André; Schiavon, N; Candeias, A; Ferreira, T; Calligaro, T; Lopes, C; Mirão, J
Fonte: Archaeometry Publicador: Archaeometry
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
68.880654%
An integrated, multi-analytical approach combining the high sensitivity of SR-mXRF, the light element capability of PIXE/PIGE under a helium flux and the spatial resolution of BSEM + EDS was used to characterize chemical composition and corrosion of glass samples (first to fourth centuries AD) from an important, but scarcely investigated, Roman region of south-west Iberia (southern Portugal). The geochemical trends and associations of major, minor and trace elements were investigated to shed light on production techniques, the provenance of raw materials and decay mechanisms. The results, while confirming a produc- tion technique common to Roman glasses throughout the Empire—that is, a silica-soda-lime low-Mg, low-K composition, with glass additives as colouring and/or decolouring agents (Fe, Cu, Mn, Sb)—show at one site high Zr–Ti contents, suggesting a more precise dating for these glasses to the second half of the fourth century. The Ti–Fe–Zr–Nb geochemical correlations in the pristine glass indicate the presence of minerals such as ilmenite, zircon, Ti-rich Fe oxides and columbite in the sands used as raw materials for the glass former: these minerals are typical of granitic-type source rocks. The unusually high K content in the corrosion layers is consistent with burial conditions in K-rich soils derived from the alteration of 2:1 clays in K-bearing rock sequences.

A COMBINED MULTI-ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH-WEST IBERIA: SYNCHROTRON micro-XRF, EXTERNAL-PIXE/PIGE AND BSEM–EDS

SCHIAVON, N.; CANDEIAS, A.; FERREIRA, T.; LOPES, M. DA CONCEIÇAO; CARNEIRO, A.; CALLIGARO, T.; MIRAO, J.
Fonte: wiley Publicador: wiley
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
99.43504%
An integrated, multi-analytical approach combining the high sensitivity of SR-mXRF, the light element capability of PIXE/PIGE under a helium flux and the spatial resolution of BSEM + EDS was used to characterize chemical composition and corrosion of glass samples(first to fourth centuries AD) from an important, but scarcely investigated, Roman region of south-west Iberia (southern Portugal). The geochemical trends and associations of major, minor and trace elements were investigated to shed light on production techniques, the provenance of raw materials and decay mechanisms. The results, while confirming a production technique common to Roman glasses throughout the Empire—that is, a silica-soda-lime low-Mg, low-K composition, with glass additives as colouring and/or decolouring agents (Fe,Cu, Mn, Sb)—show at one site high Zr–Ti contents, suggesting a more precise dating for these glasses to the second half of the fourth century. The Ti–Fe–Zr–Nb geochemical correlations in the pristine glass indicate the presence of minerals such as ilmenite, zircon, Ti-rich Fe oxides and columbite in the sands used as raw materials for the glass former: these minerals are typical of granitic-type source rocks. The unusually high K content in the corrosion layers is consistent with burial conditions in K-rich soils derived from the alteration of 2:1 clays in K-bearing rock sequences.

The Significance of Changes of Source Areas During Carboniferous Turbiditic Deposition (Southwestern Iberia)

Pereira, Manuel Francisco; Chichorro, Martim; Gutierrez-Alonso, G.; Vilallonga, Filipa; Drost, K.; Ribeiro, Carlos; Silva, J.B.; Albardeiro, Luis; Hofmann, M.; Linnemann, U.
Fonte: Springer International Publishing Publicador: Springer International Publishing
Tipo: Aula
POR
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38.588655%
U–Pb dating of detrital zircons from the Carboniferous turbidites of southwestern Iberia (the Cabrela, Mértola, Mira, and Brejeira formations) shows that synorogenic sedimentation during the Carboniferous was marked by significant variations in the source areas, involving the denudation of different crustal blocks and a break in synorogenic volcanism. The Visean is characterized by the accumulation of immature turbidites (the Cabrela and Mértola formations and the base of the Mira Formation). These turbidites were probably formed in relation to sources (magmatic arcs) of Mid–Late Devonian age poorly influenced by sedimentary recycling, as indicated by the near-absence of pre-Devonian zircons, ages that are typical of the Gondwana basement. The presence of Carboniferous grains in Visean turbidites indicates that volcanism was active at this time. Later, Serpukhovian to Moscovian turbiditic sedimentation (the Mira and Brejeira formations) included sedimentary detritus derived from mature felsic source rocks situated far from active magmatism. The abundance of Proterozoic and Palaeozoic zircons reveals strong recycling of the pre-Carboniferous basement. A peri-Gondwanan provenance is indicated by zircon populations with Neoproterozoic (the Cadomian–Avalonian and Pan-African zircon-forming events)...

Sedimentary record of the amalgamation and break-up of Pangaea: U-Pb detrital zircon geochronology and provenance of Carboniferous-Triassic siliciclastic rocks (SW Iberia)

Pereira, M. Francisco; Chichorro, Martim; Gutierrez-Alonso, Gabriel; Gama, Cristina; Drost, Kerstin; Ribeiro, Carlos; Albardeiro, Luis; Hofmann, Mandy; Linnemann, Ulf
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Aula
ENG
Relevância na Pesquisa
28.714414%
In SW Iberia there is a basal unconformity where Triassic sandstones overlie previously deformed Carboniferous turbidites. This important stratigraphic boundary records the transition from the final stages of Pangaea’s amalgamation to the initial stages of break-up. U-Pb dating of detrital zircon from Carboniferous greywackes of the South Portuguese Zone and Triassic sandstones of the Algarve and Alentejo basins was carried out to conduct a study of sedimentary provenance. The radiometric ages obtained by LA-ICP-MS show that most of the samples have common age spectra which are typical of North Gondwana sources: Archean and Paleoproterozoic ages characteristic of the West African craton, Neoproterozoic ages associated with Cadomian and Pan-African orogenies, and Cambrian ages related to the intra-continental rifting of North Gondwana. The only exception is a Visean immature greywacke that was probably derived from Devonian magmatic arcs related to the Variscan orogeny. Very rare pre-Devonian zircons indicate faint contributions from recycled sediments. In contrast the Serpukhovian to Moscovian greywackes are derived from felsic mature source rocks and include Proterozoic and Paleozoic detrital zircons suggesting recycling of an old basement. They also include Ordovician and Silurian detrital zircons...

Estudo petrológico e geoquímico do magmatismo transicional na Bacia Lusitânica

Alves, Carlos Artur Simões Ferreira
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2010 POR
Relevância na Pesquisa
17.822295%
Tese de mestrado em Geologia (Geoquímica, Mineralogia e Petrologia), apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2010; Apresentam-se e discutem-se as características petrológicas e geoquímicas do magmatismo ocorrido há cerca de 145 Ma na Bacia Lusitânica, de que resultaram dois alinhamentos sub-meridianos de rochas intrusivas entre as latitudes de Rio Maior e Soure. Este ciclo magmático, intermédio dos três que afectaram as margens Sul e Oeste da Ibéria no Mesozóico, associados à abertura do Oceano Atlântico, teve características transicionais, distinguindo-se do primeiro, sub-alcalino, toleítico, ocorrido há cerca de 200Ma, e do terceiro, alcalino, datando do Cretácico Superior. Apresentam-se, para rochas deste ciclo transicional, três novas idades 40Ar/39Ar que, juntamente com idades U-Pb recentemente publicadas, sugerem uma duração de cerca de 6 Ma para este ciclo magmático, muito inferior à anteriormente considerada (~32 Ma). Os novos dados atribuem também, contrariamente ao que se supunha, idade semelhante às rochas de ambos os alinhamentos. A variabilidade química destas rochas, demonstrada por análises de rocha total de um conjunto representativo de amostras, com determinação de elementos maiores e traço...

Análise do regime gravítico-inercial das correntes sobre a plataforma continental do Algarve

Trindade, Ana Filipa Mestre, 1985-
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2011 POR
Relevância na Pesquisa
17.822295%
Tese de mestrado em Ciências Geofísicas, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2011; Este estudo é centrado sobre a plataforma continental do Algarve, situada no extremo Norte do Golfo de Cádis, e apoia-se principalmente na análise de 4 series correntométricas, obtidas sobre a plataforma continental ao largo de Faro durante o período aproximado de 4meses,entre Fevereiro e Junho 2006. O objectivo principal do estudo é analisar e interpretar dinamicamente os dados de forma a caracterizar a variabilidade sinóptica e sazonal das correntes para o período temporal da série, assim como a evolução dos campos da temperatura e da condutividade medidos por cada correntómetro. Para a análise sinóptica foram utilizados ventos locais e ao largo, adquiridos em Tavira e num ponto ao largo da parte Sul da costa ocidental da Península Ibérica . As series temporais dos correntómetros foram analisadas no domínio do tempo, da frequência e simultaneamente em ambos os domínios através da análise por onduletas. As observações correntométricas indicaram sobre a vertente um escoamento superficial médio para Este, concordante com uma corrente costeira que se especula seguir ao longo da costa Nordeste do Golfo até ao Estreito de Gibraltar. A profundidades intermédias (120-190 m) a corrente média observada é para Oeste durante toda a série temporal. Contrariamente...

The Neogene of the Lower Tagus Basin (Portugal)

Pais, João
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Artigo de Revista Científica
Publicado em 25/03/2010 ENG
Relevância na Pesquisa
17.822295%
Revista Española de Paleontologia 19 (2), 229-242; The Tertiary Lower Tagus Basin (LTB) occupies a large area in Portugal and constitutes a symmetric basin of the oriental huge Upper Tagus Basin, centered at Madrid (Spain). The LTB was an endorreic basin during the Paleogene. Marine connection occurred at the Lower Aquitanian; at the Lisbon – Setúbal Peninsula region the sedimentation was in the ocean/continent interface, with several changes in the coast line. Apparently, the first marine transgression came from South, originating a gulf with a N-S coral reef that attained the Lisbon area. Occidental communication to the sea was established after the Burdigalian.The sedimentary and palaeontologic record of the distal sector of the LTB (Lisbon –Setúbal Peninsula) is related to sea level changes. It is possible to correlate levels with planctic foraminifera and mammals, as well as to get isotopic ages (K/Ar in glauconites; 87Sr/86Sr). Good biostratigraphic data can be obtain from continental and coastal deposits. The fossil richness – dinoflagellates, spores, pollen, plant macrorremains, foraminifera, ostracoda, molluscs, echinids, fishes, reptiles, mammals – and O and C isotopes, constitutes a large source of information for environmental and palaeogeographical reconstitutions...

Tectonics of the West Iberia continental margin from seismic reflection data

Henning, Alison Teagan
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
49.142554%
Continental rifting is a fundamental component of the plate tectonic cycle. The West Iberia passive margin is a classic example of a nonvolcanic rifted margin. The West Iberia margin contains an enigmatic north-south ridge of serpentinized peridotite located within the ocean-continent transition. Interpretation of multichannel seismic data and tectonic subsidence analyses suggests that the ridge is located within a broad zone of exhumed mantle that has been serpentinized. This implies that seafloor spreading does not immediately follow continental breakup. Where the peridotite ridge is well-developed, it parallels a deeply-penetrating, west-dipping normal fault. Hydrodynamic circulation drove seawater down this fault close to the beginning of seafloor spreading and caused a concentration of serpentinization at its base. This water-driven process of formation accounts for the variability of the ridge along strike. Prestack depth migration of a 340 km long seismic reflection profile across the margin served as the basis for stratigraphic interpretation. The proximal margin displays horsts and grabens, with 1--2 km thick synrift deposits from Early Cretaceous (Valanginian) rifting. The deep water margin displays rotated blocks with distinct internal seismic patterns. These blocks formed during the final Cretaceous rifting event that led to continental breakup...

New population and phylogenetic features of the internal variation within mitochondrial DNA macro-haplogroup R0

Álvarez Iglesias, Vanesa; Mosquera Miguel, Ana; Cerezo, María; Quintáns, Beatriz; Zarrabeitia Cimiano, María Teresa; Cuscó, Ivon; Lareu, María Victoria; García, Óscar; Pérez Jurado, Luis; Carracedo Álvarez, Ángel; Salas Ellacuriaga, Antonio
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: info:eu-repo/semantics/article; publishedVersion
ENG
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18.888683%
BACKGROUND: R0 embraces the most common mitochondrial DNA (mtDNA) lineage in West Eurasia, namely, haplogroup H (approximately 40%). R0 sub-lineages are badly defined in the control region and therefore, the analysis of diagnostic coding region polymorphisms is needed in order to gain resolution in population and medical studies. METHODOLOGY/PRINCIPAL FINDINGS: We sequenced the first hypervariable segment (HVS-I) of 518 individuals from different North Iberian regions. The mtDNAs belonging to R0 (approximately 57%) were further genotyped for a set of 71 coding region SNPs characterizing major and minor branches of R0. We found that the North Iberian Peninsula shows moderate levels of population stratification; for instance, haplogroup V reaches the highest frequency in Cantabria (north-central Iberia), but lower in Galicia (northwest Iberia) and Catalonia (northeast Iberia). When compared to other European and Middle East populations, haplogroups H1, H3 and H5a show frequency peaks in the Franco-Cantabrian region, declining from West towards the East and South Europe. In addition, we have characterized, by way of complete genome sequencing, a new autochthonous clade of haplogroup H in the Basque country, named H2a5. Its coalescence age...

Economic integration and regional inequality in Iberia (1900-2000) : a geographical approach

Tirado, Daniel A.; Badia-Miró, Marc
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: info:eu-repo/semantics/draft; info:eu-repo/semantics/workingPaper Formato: application/pdf
Publicado em /02/2012 ENG
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This paper studies the evolution of regional inequality in Iberia from 1900 to 2000 from a geographical perspective. For doing that the text presents a new dataset of historical regional GDPs for Spanish NUTS III and Portuguese Historical Districts (HD), synthetic indices of regional inequality and different measures of spatial correlation across regional pc GDPs. The results show that Portuguese and Spanish national economic integration processes initially favored the economic specialization across Iberian regions fostering the divergence in terms of their regional pc GDPs. Notwithstanding, ulterior advances in the integration of national markets and the subsequent first stages in the process of adhesion of these two national economies into the UE coexisted with a progressive reduction in Iberian regional inequality. So, Iberian regional inequality depicts a long term U-shaped evolution. Nevertheless, at the same time, Iberian regional inequality evolution followed a significant geographical pattern. The poorest regions cluster in inland territories of the south and west, with regions belonging to this cluster sited on the two sides of the political border. On the contrary, richest regions cluster along the coasts, especially in the north-east corner of the Iberian Peninsula. Besides...

Archeologia del Mezzo Acquatico nel Garb al-Andalus Porti, Arsenali, Cantieri e Imbarcazioni

Amato, Alessia
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
ITA
Relevância na Pesquisa
17.822295%
This study is aimed to define its own characteristics within the chronological sphere of the Muslim occupation on the Iberian Peninsula and particularly on the development which involves the Southern region of Portugal, bound between the low Tejo (Lisbon) and the Algarve. The analysis of the relationship between this People and the sea with its components precedes the period of the great conquest, which see the Christian Reign of Portugal engaged in an area beyond the Ocean – from the end of XV Century onwards – anyway engaged outside the Mediterranean basin and in the classical circuits that have had their exclusive attention until that time. During the Islamic period, VIII-XIII, one sees the vitality of the port cities, with the development of nautical activities, including naval construction in shipyards mentioned by Arab authors, such as Al-Razi, Al-Bakri, Ibne Mozaine and al-Idrisi. Various descriptions made by Arab historians and geographers with a common vision of these territories considered as a prolongation of the eastern Arab world reachable through North Africa and most likely via navigation along the coast. Al-Razi proposes a significant division of Andalusia into Ax-Xarqi and al- Garbe or, in other words, eastern and western Andalusia. Al- Garbe corresponds to current Southern Portugal Although the Arabic literary sources and the corpus of the Medieval Arabian geography constitute the primary sources for the study of the use of the coast and shipping lanes during the Arab dominion of Southern Portugal...

Análise de proveniência sedimentar das bacias de carbónico e do triásico do SW de Portugal (Alentejo e Algarve): contributo para o conhecimento dos processos de formação e fragmentação do supercontinente Pangeia

Vilallonga, Filipa Andrade Santos Robalo
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Tese de Doutorado
POR
Relevância na Pesquisa
19.437725%
Neste trabalho foram estudadas rochas sedimentares detríticas do SW da Ibéria, pertencentes ao soco Carbónico da Zona Sul Portuguesa e ao Triásico superior das bacias do Alentejo e do Algarve. Pretendeu-se analisar a proveniência destas rochas sedimentares e discutir os modelos geodinâmicos e paleogeográficos associados à sua deposição durante a formação e fragmentação do supercontinente Pangeia. O trabalho incidiu sobre: i) caracterização as relações estratigráficas do soco Carbónico (formações de Mértola, de Mira e da Brejeira) com a discordância da base do Triásico superior (Formação dos Arenitos de Silves), ii) petrografia sedimentar, iii) geoquímica de rocha total e iv) geocronologia U-Pb em zircão detrítico. As formações do Carbónico que se se depositaram em bacias marinhas sinorogénicas relacionadas com a formação da Pangeia (contemporâneas com a colisão entre Laurussia e Gondwana) revelam alguma diversidade da sua história sedimentológica apresentando: i) áreas-fonte diversas ou heterogéneas, ii) sedimentogénese distinta e iii) histórias complexas de reciclagem sedimentar. As rochas detríticas do Triásico superior que se depositaram em bacias intra-continentais associadas à fragmentação da Pangeia...

Spatial patterns of wind and sea surface temperature in the Galician upwelling region

Torres, R.; Barton, Eric D.; Miller, P.; Fanjul, E.
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artículo Formato: 502604 bytes; application/pdf
ENG
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28.122322%
14 pages, 14 figures.-- Full-text version available Open Access at: http://www.iim.csic.es/~barton/html/pdfs.html; Cape Finisterre is the most northwest point in the Galician region and separates the meridional west and zonal north coasts of Galicia. The wind field there has high spatial and temporal variability throughout the year. No clear seasonal signal is evident; upwelling and nonupwelling patterns alternate in all seasons. Two outstanding features of the Galician region are persistent upwelling near Cape Finisterre even when not present farther south and alternation of strong upwelling on north and west coasts. Up to now, explanations have relied upon particular dynamics of oceanic flow past Finisterre. We find that major features of upwelling around Finisterre are related to strong spatial structure in the wind field. Analysis of QuikScat wind data for July 1999 to May 2001 shows strong repeatable patterns in the synoptic wind field. These wind patterns emerge as the combination of the two dominant modes in a complex empirical orthogonal function (CEOF) analysis representing over 85% of the variance. Summer wind patterns give rise to characteristic distributions of upwelling along the coast and favor development of filaments in particular locations. The wind measured at Finisterre itself...

Subduction-related structures in the North Iberian Margin

Alvarez-Marrón, Joaquina; Rubio, Luis Eduardo; Torne, Montserrat
Fonte: American Geophysical Union Publicador: American Geophysical Union
Tipo: Artículo Formato: 918459 bytes; application/pdf
ENG
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18.377732%
14 pages, 8 figures.; The oblique convergence of Eurasia and Iberia since the Early Cretaceous, caused the formation of the Pyrenean intracontinental collisional orogen in the east, and progressed to continent-ocean collision with subduction of the Bay of Biscay oceanic crust beneath the North Iberian Margin in the west. Two deep multichannel seismic profiles (IAM-12 and ESCIN-4), integrated with gravity modeling and other geological and geophysical data, provide the crustal-scale architecture of this margin and its tectonic evolution during the convergence. The North Iberian Margin is modeled with a South or south-southeast dipping oceanic crust beneath the outer part of the continental shelf. Mesozoic basins on the shelf were inverted during the Tertiary, and compressional activity continued until recent times in the ESCIN-4 section, while a shallower, probably Neogene age basin is subjected to active recent erosion in the IAM-12 section. In the oceanic areas, a marginal trough deepens and widens toward the east as a result of the regional east dip of the oceanic basement. The accretionary prism increases in size from west to east (18–56 km), and its internal structure and morphology varies along strike. The prism is buried by postcorivergence sediments in both sections and in the IAM-12 section appears to have been active at least during Lutetian to Burdigalian times. The crustal-scale structure of the North Iberian Margin is that of an arrested subduction zone in which a remnant oceanic basin was being consumed near two continental plates that collided obliquely.; The ESCIN program was sponsored by the Spanish agencies CICYT (project GEO 90-0660) and FICYT...