355 resultados para Variscan Iberia


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En el presente artículo analizamos los desplazamientos de cultos indígenas hispanos desde distintas áreas de la Península Ibérica hacia los principales lugares de inmigración en Hispania: las áreas mineras y las ciudades. Proponemos que estos grupos de emigrantes rendían culto en su nueva residencia a las deidades que veneraban en sus regiones de procedencia como un medio de preservar su cohesión social y su identidad cultural. La dureza de la vida laboral en las áreas mineras reforzaba la necesidad de fortalecer los lazos culturales.

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En 1865 Narcisa Pérez Reoyo publica en A Coruña su primer poemario, Cantos de la infancia, prologado por Manuel Murguía y que incluye un poema dedicado a Rosalía de Castro. Este artículo se ocupa de las relaciones del matrimonio Murguía-Castro con la escritora novel, en el contexto de la literatura escrita por mujeres en el siglo XIX y de la construcción de la literatura gallega.

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O complexo batolítico das Beiras está localizado na Zona Centro Ibérica (ZCI), no centro norte de Portugal. É predominantemente composto por rochas granitóides instaladas em metassedimentos de idade Neoproterozóica - Câmbrica Inferior, Ordovícica e Carbonífera Superior, durante ou após a última fase de deformação dúctil varisca (D3). No seu conjunto, as rochas granitóides do Batólito das Beiras cobrem um amplo espectro de idades (sin-, tardi- e tardi-pós-D3) e tipologias (tipo S e transicionais I-S). Neste trabalho apresentam-se dados petrográficos, mineralógicos, geoquímicos e isotópicos para estas intrusões e discutem-se os principais processos envolvidos na sua génese.

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This paper discusses the advantages of using a combined environmagnetic and geochemical approach to the provenance and characterization of distal IRDs occurring during the Last Glacial Period in core CI12PC3 from the Galicia Interior Basin (GIB). Six Heinrich layers (HL1-6) have been identified in the area in base to the detection of distinct populations of exotic magnetic mineral assemblages alien to the local/regional sedimentation environment. Their extension has been determined by Ca/Sr and Si/Sr ratios and their provenance by 143Nd/144Nd and 87Sr/86Sr isotopic ratios and FORCs. The sedimentary expression of HL is characterized by the presence of distal Ice Rafted Detritus (IRD). Distal IRD magnetic signatures in the GIB consist of (i) an increase of one order of magnitude in the peak amplitude of magnetic susceptibility from background values, (ii) a general coarsening of the magnetic grain size in a mineral assemblage dominated by titano-magnetites, (iii) FORC distributions pushing towards the coarse MD or PSD component, and (iv) thermomagnetic curves depicting the occurrence of several magnetite phases. These four features are very different from the fine-grained biogenic magnetic assemblages characterized by the combination of lower MS and higher coercivity values that dominate the predominant mixtures of the non-interacting SSD and PSD components in the non-IRD influenced background sedimentation. Our results show that the last 70.000 yr of sedimentation in the GIB were controlled by the relative contribution of local detrital material derived from the Iberian Variscan Chain and IRD alien material from the iceberg melting during the Heinrich Events. They also show two main IRD provenance fields: Europe and Canada. And that the later is more important for for HL1, HL2, HL4 and HL5. FORCs analysis complemented the isotopic information and provided a very unique information, indicating that glacial flour may not always have the same provenance as IRD and that ice-melted derived suspended sediment has its own dynamics and may reach further and/or persists longer than IRD.

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The Biarjmand granitoids and granitic gneisses in northeast Iran are part of the Torud–Biarjmand metamorphic complex, where previous zircon U–Pb geochronology show ages of ca. 554–530 Ma for orthogneissic rocks. Our new U–Pb zircon ages confirm a Cadomian age and show that the granitic gneiss is ~30 million years older (561.3 ± 4.7 Ma) than intruding granitoids(522.3 ± 4.2 Ma; 537.7 ± 4.7 Ma). Cadomian magmatism in Iran was part of an approximately 100-million-year-long episode of subduction-related arc and back-arc magmatism, which dominated the whole northern Gondwana margin, from Iberia to Turkey and Iran. Major REE and trace element data show that these granitoids have calc-alkaline signatures. Their zircon O (δ18O = 6.2–8.9‰) and Hf (–7.9 to +5.5; one point with εHf ~ –17.4) as well as bulk rock Nd isotopes (εNd(t)= –3 to –6.2) show that these magmas were generated via mixing of juvenile magmas with an older crust and/or melting of middle continental crust. Whole-rock Nd and zircon Hf model ages (1.3–1.6 Ga) suggest that this older continental crust was likely to have been Mesoproterozoic or even older. Our results, including variable zircon εHf(t) values, inheritance of old zircons and lack of evidence for juvenile Cadomian igneous rocks anywhere in Iran, suggest that the geotectonic setting during late Ediacaran and early Cambrian time was a continental magmatic arc rather than back-arc for the evolution of northeast Iran Cadomian igneous rocks.

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The red deer (Cervus elaphus) is currently one of the most widespread and abundant wild ungulates in the Iberian Peninsula and is extremely important both ecologically, as a key species for the functioning of the ecosystems, and economically, as a major game species. In Iberia, red deer populations are subjected to different management systems that may affect the physical condition of the individuals, with further consequences for population dynamics. Studies investigating the effects of management practices and environmental conditions on the performance of red deer are still rare regarding Mediterranean ecosystems. Much of the knowledge concerning the ecology of red deer and the impact of management on its physical condition is based on studies conducted in northern and central regions of Europe, where climatological features and management practices differ from those observed in the Mediterranean areas of Iberia. Studies on a biogeographical scale can provide important insights into the relationships between species and a particular environment and contribute to the development of more targeted and appropriate management practices. The optimisation of sampling procedures and the fine-tuning of pre-existing analytical techniques are also fundamental to a more cost-effective monitoring and, therefore, are of enormous value to wildlife managers. In this context, the main aims of this thesis were: 1) to optimise the procedures used to assess the physical condition of red deer; and 2) to identify relevant management and environmental factors affecting the nutritional condition and stress physiology of red deer in the Mediterranean ecosystems of Iberia, as well as any potential interactions between those factors. Two studies with a methodological focus, presented in the first part of the thesis, demonstrated that the physical condition of red deer can be evaluated more simply, using more cost- and time-effective procedures than those traditionally used: i) it was shown that only one kidney and its associated fat is enough to assess nutritional condition in red deer; and ii) the feasibility of using near infrared spectroscopy to predict the concentrations of stress hormone metabolites was demonstrated using faeces of red deer for the first time. Subsequently, two large-scale observational studies, conducted in representative red deer populations found in Mediterranean Iberia, highlighted the importance of considering seasonal environmental variations and variables related to hunting management practices to better understand the nutritional and physiological ecology of red deer. High population densities had adverse effects on the nutritional condition of the deer and were associated with increased stress levels in natural populations without supplementary feeding. Massive hunting events involving the use of hounds were also identified as a potential source of chronic stress in red deer. The research presented in this thesis has clear implications regarding the management and monitoring of red deer populations in Mediterranean environments and is intended to help wildlife managers to implement more effective monitoring programmes and sustainable management practices.

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Within the Kauffung Limestone dolomite bodies related to volcanic contacts occure and are interpreted as a post-Variscan, hydrothermal volcanogenic formation. Two genetic dolomite types are discernible: a pervasive replacement saddle dolomite and a cavity filling saddle dolomite cement. Micro texture and oxygen isotopy of both dolomite types refer to heightened temperatures of formation. The ocurrence of the dolomite in contact to cross-cutting rhyolithic dikes points to a close petrogenetic relation. Dolomite bodies and rhyolithic injections in contrast to the rock wall are characterized by a distinctive cavernous texture, so that a prekinematic genesis is excluded. The formation of replacement saddle dolomite and saddle dolomite cement altogether are considered as a concomitant phenomenon of the Permo-Carboniferous volcanism widespread in the Bober-Katzbach Mountains.

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O presente trabalho ocupa-se do estudo do Complexo Xisto-Grauváquico ante-ordovícico (Grupo das Beiras) na região do Caramulo-Buçaco (centro de Portugal). Em termos geológicos, a área estudada pertence à Zona Centro Ibérica e encontra-se limitada a N pelo granito do Caramulo, a S pela bacia meso-cenozóica de Arganil, a W pelo sinclinal paleozóico do Buçaco e pela bacia meso-cenozóica ocidental portuguesa e a E pelo sinclinal paleozóico de Arganil e pelo plutonito granítico de Tábua-Santa Comba Dão; no seio da área estudada encontra-se a bacia meso-cenozóica de Mortágua. Com base nas características litológicas e estruturais distinguem-se no Complexo Xisto Grauváquico 4 grandes conjuntos litológicos concordantes entre si, designados de Unidades I, II, III e IV, que se desenvolvem da base para o topo de N para S. A Unidade I situa-se a N da região. O seu limite inferior é desconhecido, e o superior posiciona-se no último conjunto arenoso com potência decamétrica. É constituída por xistos cinzentos e negros com intercalações de arenitos de espessura não superior a 100 metros e de extensão lateral quilométrica. Apresenta uma espessura mínima de 1000 m. A Unidade II apresenta consideravelmente menor proporção de material arenoso intercalado entre os pelitos comparativamente à unidade inferior. É caracterizada por apresentar um predomínio de material silto-argiloso e escassos níveis arenosos com potência não superior à dezena de metros e escassa continuidade lateral. Cartograficamente esta unidade constitui uma franja alargada de orientação próxima a E-W. Apresenta uma espessura aproximada de 1500 m. A Unidade III é caracterizada pela presença de conjuntos arenosos com extensão lateral quilométrica e espessura de várias dezenas de metros, separados por material silto-argiloso. Os limites inferior e superior estão situados respectivamente abaixo e acima dos principais conjuntos arenosos. Esta unidade apresenta uma espessura máxima estimada na ordem dos 2000 m. A Unidade IV, que é a unidade superior, apresenta um predomínio pelítico, com escassas intercalações de conjuntos arenosos. O seu limite inferior encontra-se no topo do último conjunto arenoso da Unidade III. Apresenta uma espessura mínima de 500 m. As características sedimentológicas das 4 unidades indicam uma sedimentação num ambiente de plataforma externa siliciclástica aberta, com a construção de barras e por vezes sujeita à acção de tempestades, com sucessivos períodos de superficialização e profundização numa bacia de sedimentação bastante subsidente. Em termos estruturais, para além duma deformação pré-ordovícica, que é comprovada pelo forte mergulho e dispersão da orientação dos eixos da 1ª fase varisca e da lineação de intersecção L1, a área estudada foi principalmente afectada pela Orogenia Varisca. A 1ª fase de deformação varisca (F1) gerou dobras com superfícies axiais e xistosidade associada (S1) de direcção WNW-ESE, e forte pendor para NNE. Estas dobras D1 apresentam comprimentos de onda que nunca chegam a ser quilométricos, desenvolvendo-se um grande flanco inverso denunciando a presença de uma antiforma para NNE e uma sinforma para SSW. A 2ª fase de deformação varisca (F2) actuou na parte nordeste da área estudada e é caracterizada por ter gerado dobras de comprimento de onda quilométrico, com planos axiais e xistosidade associada S2 de direcção NW-SE, subverticais ou a pender fortemente para NE. Embora com alguma dispersão, as lineações de intersecção L2 e os eixos das dobras D2 apresentam maioritariamente forte pendor para E. A direcção e tipos de estruturas da F2 sugerem uma correlação com a terceira fase definida em vários pontos da Zona Centro Ibérica e estreitamente relacionada com as intrusões graníticas. Do ponto de vista petrológico, distinguem-se várias rochas sedimentares (pelitos e arenitos) todas elas sujeitas a metamorfismo que não ultrapassa a fácies dos xistos verdes. Dentro das rochas sedimentares mais grosseiras, há a destacar a presença de arenitos vulcânicos cuja composição denuncia, não muito afastados da bacia sedimentar, a presença de aparelhos vulcânicos que estariam em actividade durante a sedimentação. Foram analisadas isotopicamente 27 amostras de metapelitos colhidas em 5 locais diferentes de forma a abranger quase toda a área estudada. Os dados isotópicos de quatro destes locais de amostragem forneceram isócronas Rb-Sr, em rocha total, com valores da ordem dos 400-440 Ma. O granito do Caramulo, datado pela isócrona Rb-Sr em amostras de rocha total, forneceu uma idade de 326±12Ma. As idades modelo Sm-Nd (manto empobrecido) de 5 amostras de metapelitos estão compreendidas entre 1.35 e 1.25 Ga. Este período de tempo pode ser considerado como correspondendo à época de diferenciação mantélica da crusta que deu lugar à maioria das áreas fonte dos metapelitos.

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Amongst migratory species, it is common to find individuals from different populations or geographical origins sharing staging or wintering areas. Given their differing life histories, ecological theory would predict that the different groups of individuals should exhibit some level of niche segregation. This has rarely been investigated because of the difficulty in assigning migrating individuals to breeding areas. Here, we start by documenting a broad geographical gradient of hydrogen isotopes (δ (2)H) in robin Erithacus rubecula feathers across Europe. We then use δ (2)H, as well as wing-tip shape, as surrogates for broad migratory origin of birds wintering in Iberia, to investigate the ecological segregation of populations. Wintering robins of different sexes, ages and body sizes are known to segregate between habitats in Iberia. This has been attributed to the despotic exclusion of inferior competitors from the best patches by dominant individuals. We find no segregation between habitats in relation to δ (2)H in feathers, or to wing-tip shape, which suggests that no major asymmetries in competitive ability exist between migrant robins of different origins. Trophic level (inferred from nitrogen isotopes in blood) correlated both with δ (2)H in feathers and with wing-tip shape, showing that individuals from different geographic origins display a degree of ecological segregation in shared winter quarters. Isotopic mixing models indicate that wintering birds originating from more northerly populations consume more invertebrates. Our multi-scale study suggests that trophic-niche segregation may result from specializations (arising in the population-specific breeding areas) that are transported by the migrants into the shared wintering grounds.

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En este trabajo nos dedicamos a estudiar, a través de la lectura de distintas fuentes escritas, la visión que sobre la niñez tenían los grupos cristianos y musulmanes de la Península Ibérica durante la Edad Media. Consideraremos aspectos de la vida infantil como el nacimiento, las figuras que influyen en los primeros momentos de sus vidas, la crianza, la educación, la salud y la muerte, y veremos los puntos en común y de enriquecimiento mutuo entre las dos culturas. Rescataremos también las diferencias que se plantean en determinados temas de acuerdo al punto de vista religioso y cultural de cada grupo en particular.

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Reinterpretation of old heat flow data or use of new data and new techniques of detection of the temperature under the surface have conducted to new heat flow density values in some regions of the globe. The problem of ice melting in Greenland and Antarctica caught the public's attention to the importance of knowledge on heat flow values and thermal structure of the globe. In the last years, several models were presented trying to obtain lithosphere and Moho thickness of the Iberia Peninsula. The work we intend to present is related with the SW part of the Iberia Peninsula ( south of the Ossa Morena zone, South Portuguese Zone and Algarve). The results obtained show a decrease in the thickness of the crust and the lithosphere in this region. Density anomalies in the crust are also referred. I intend to make the connection between the results of these models and the heat flow thermal conductivity, heat production and geological data available for the region, trying to explain the results of heat flow density data obtained.

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BACKGROUND Infections with Mycobacterium bovis and closely related members of the Mycobacterium tuberculosis complex (MTC) are shared between livestock, wildlife and sporadically human beings. Wildlife reservoirs exist worldwide and can interfere with bovine tuberculosis (TB) eradication efforts. The Eurasian wild boar (Sus scrofa) is a MTC maintenance host in Mediterranean Iberia (Spain and Portugal). However, few systematic studies in wild boar have been carried out in Atlantic regions. We describe the prevalence, distribution, pathology and epidemiology of MTC and other mycobacteria from wild boar in Atlantic Spain. A total of 2,067 wild boar were sampled between 2008 and 2012. RESULTS The results provide insight into the current status of wild boar as MTC and Mycobacterium avium complex (MAC) hosts in temperate regions of continental Europe. The main findings were a low TB prevalence (2.6%), a low proportion of MTC infected wild boar displaying generalized TB lesions (16.7%), and a higher proportion of MAC infections (4.5%). Molecular typing revealed epidemiological links between wild boar and domestic - cattle, sheep and goat - and other wildlife - Eurasian badger (Meles meles) and red fox (Vulpes vulpes) - hosts. CONCLUSIONS This study shows that the likelihood of MTC excretion by wild boar in Atlantic habitats is much lower than in Mediterranean areas. However, wild boar provide a good indicator of MTC circulation and, given the current re-emergence of animal TB, similar large-scale surveys would be advisable in other Atlantic regions of continental Europe.

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Underwater video transect methods using small remotely operated vehicles (ROVs) and diveroperated video (DOV) are commonly used in benthic biodiversity assessments. Constraints posed by deeper waters have made surveys of the circalittoral zone ([30 m depth), a particularly challenging problem. Here we compare benthic diversity metrics and cluster analyses obtained with ROV and DOV between 45 and 65 m depth off southwest Iberia, across local (tens to hundreds of meters) and regional scales (tens of kilometers). Results showed no difference between methods in terms of the benthic species richness, taxonomic distinctness, and beta diversity, but only minor differences in the spatial structure depicted at the regional level. At the local scale, DOV performed better at discriminating patterns likely because of the divers visual acuity. We found that small ROV and DOV are reliable and comparable methods for the study of circalittoral benthic assemblages and can be used in a complimentary way to detect the greatest amount of variation in benthic ecosystems. Our study facilitates the understanding of capabilities and limitations of two underwater video methods and provides important insight into choice of the most appropriate technique.

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This study examines the long profiles of tributaries of the Tejo (Tagus) and Zêzere rivers in central eastern Portugal (West Iberia) in order to provide new insights into the patterns, timing and controls on drainage development during the Pleistocene to Holocene incision stage. The long profiles were extracted from lower order tributary streams associated with the trunk drainage of the Tejo River and one main tributary, the Zêzere River (Fig. 1). These streams flow through a landscape strongly influenced by variations in bedrock lithology (mainly granites and metasediments), fault structures delimiting crustal blocks with distinct uplift rates, and a base-level lowering history (tectonic uplift / eustatic). The long profiles of the tributaries of the Tejo and Zêzere rivers record a series of transient and permanent knickpoints. The permanent knickpoints have direct correlation with the bedrock strength, corresponding to the outcropping of very hard quartzites or to the transition from softer (slates/metagreywaques) to harder (granite) basement. The analyzed streams/rivers record also an older transient knickpoint/knickzone separating: a) an upstream relict graded profile, with lower steepness and higher concavity, that reflects a long period of quasi-equilibrium conditions reached after the beginning of the incision stage; and b) a downstream reach displaying a rejuvenated long profile, with steeper gradient and lower concavity, particularly for the final segment, which is often convex (Fig. 2). The rejuvenated reaches testify the upstream propagation of several incision waves that are the response of each stream to continuous or increasing crustal uplift and dominant periods of base-level lowering by the trunk drainages, coeval of low sea level conditions. The long profiles and their morphological configurations enabled spatial and relative temporal patterns of incision to be quantified for each individual tributary stream. The incision values of streams flowing in uplifted blocks of the Portuguese Central Range (PCR) (ca.380-280 m) indicate differential uplift and are higher than the incision values of streams flowing on the adjacent South Portugal planation surface – the Meseta (ca. 200 m). The normalized steepness index, calculated using the method of Wobus et al. (2006), proved to be sensitive to active tectonics, as lower ksn values were found in relict graded profiles of streams located in less uplifted blocks, (e.g. Sertã stream in the PCR), or in those flowing through tectonic depressions. Fig. 1 – Geological map of the study area. 1 – fluvial terraces (Pleistocene); 2 – sedimentary cover (Paleogene and Neogene); 3 – slates and metasandstones (Devonian); 4 – slates and quartzites (Silurian); 5 – quartzites (Ordovician); 6 – slates and metagreywackes (Precambrian to Cambrian); 7 – slates, metagreywackes and limestones (Precambrian); 8 – granites and ortogneisses; 9 – diorites and gabros; 10 - fault. SFf – Sobreira Formosa fault; Sf – Sertã fault; Pf – Ponsul fault; Gf – Grade fault. The differential uplift indicated by the distribution of the ksn values and by the fluvial incision was likely accumulated on a few major faults, as the Sobreira Formosa fault (SFf), thus corroborating the tectonic activity of these faults. Due to the fact that the relict graded profiles can be correlated with other geomorphic references documented in the study area, namely the T1 terrace of the Tagus River (with an age of ca. 1 Myr), the following incision rates can be estimated: a) for the studied streams located in uplifted blocks of the PCR, 0.38 m/kyr to 0.28 m/kyr; b) for the streams flowing on the South Portugal planation surface, 0.20 m/kyr. The differential uplift inferred between crustal blocks in the study area corroborates the neotectonic activity of the bordering faults, which has been proposed in previous studies based upon less robust data. Fig. 2 – Longitudinal profile of the Nisa stream a tributary of the Tejo River. Note the equilibrium relict profile upstream the older transient knickpoint (hatched line) and the downstream rejuvenated profile (continuous line). Legend: tKP – transient knickpoint; rKp – resistant knickpoint; Mt – schist and phyllite; Gr – granite; Hf – hornfels; Og – orthogneisse. In the inset Distance – Slope plots, fill circles correspond to the relict graded profile, crosses correspond to the rejuvenated profile located downstream the older transient knickpoint (tKP).

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This study examines the long profiles of tributaries of the Tagus and Zêzere rivers in Portugal (West Iberia) in order to provide new insights into patterns, timing, and controls on drainage development during the Quaternary incision stage. The studied streams are incised into a relict culminant fluvial surface, abandoned at the beginning of the incision stage. The streams flow through a landscape with bedrock variations in lithology (mainly granites and metasediments) and faulted blocks with distinct uplift rates. The long profiles of the analyzed streams record an older transitory knickpoint/knickzone separating (1) an upstream relict graded profile, with lower steepness and higher concavity, that reflects a long period of quasi-equilibrium conditions reached after the beginning of the incision stage, and (2) a downstream rejuvenated long profile, with steeper gradient and lower concavity, particularly for the final reach, which is often convex. The rejuvenated reaches testify to the upstream propagation of several incision waves, interpreted as the response of each stream to increasing crustal uplift and prolonged periods of base-level lowering by the trunk drainages, coeval with low sea level conditions. The morphological configurations of the long profiles enabled spatial and relative temporal patterns of incisions to be quantified. The incision values of streams flowing on the Portuguese Central Range (PCR; ca. 380–150 m) are variable but generally higher than the incision values of streams flowing on the adjacent South Portugal Planation Surface (SPPS; ca. 220–110 m), corroborating differential uplift of the PCR relative to the SPPS. Owing to the fact that the relict graded profiles can be correlated with the Tagus River T1 terrace (1.1–0.9 My) present in the study area, incision rates can be estimated (1) for the streams located in the PCR, 0.38–0.15 m/ky and (2) for the streams flowing on the SPPS, 0.22–0.12 m/ky. The differential uplift inferred in the study area supports the neotectonic activity of the bordering faults, as proposed in previous studies based upon other geological evidence.