A sedimentação e a gliptogénese no registo cenozóico continental do Minho (NW Portugal)

This study identifies and describes the major Cenozoíc glyptogenesis and sedimentation episodes in the Minho region (NW Portugal). The fluvial processes of exorheic network were mainly the builders of Cenozoic landscape. This paper presents a chronological sequence of the major fluvial events based on geomorphology and sedimentary characteristics obtained in former studies and new ones. The oldest Cenozoic sedimentation (Placencian) remains on local depressions and was generated by fluvial and fluvio-lacustrine processes. Quaternary glyptogenesis begins probably with a major European cooling (Gunz?). So, the Placencian infilling was eroded and a new episode of sedimentation was accumulated in the same early paleovalley. There were three more cycles of quaternary glyptogenesis and sedimentation. The last glyptogenesis episode records the last glacial period. The post-glacial alluvion contains clasts of granites, schists, feldspats, and other alterable lithologies and minerals; on clay dimensions there are abundant illite and interstratified minerals. This composition differs from the older ones, more siliciclastic and kaolinitic. Other minor erosion episodes were identified, controlled manly by eustasy; evidences of tectonic movements were observed only in rio Minho valley.

Depósitos continentais e marinhos na plataforma litoral da região do Porto. Importância da tectónica na sua organização espacial

One of the most common characteristics of Portuguese littoral is the existence of a planed surface (the so-called "littoral platform"), situated at different altitudes and bordered from the inland by a straight relief, strongly contrasting with that planed surface. This one is generally covered with several outcrops of the so-called Plio-Pleistocene deposits. Till the eighties this platform has been interpreted as stable staircase of old marine levels, registering in a passive way the eustatic variations. The rigid step bordering it easterly should be a fossil cliff. However, our study has proved that many of these deposits have a continental origin. These continental deposits have fluvial or alluvial fan facies and they are lying above 40 meters. Marine deposits seem to be quite rare and they only occupy a small western area, beneath the altitude of 40 meters and developing into three different marine levels. There is a rigid step between the two kinds of deposits. We think that the clear geometric separation between these deposits together with this rigid step, indicates a tectonic origin. It seems that the sea must have touched only the western part of this surface, when neotectonic movements lowered it down. There are more evidences for neotectonic movements: a) there are faults (mainly inverse faults) affecting the higher deposits of this littoral platform; b) the same marine level seems to appear at different altitudes, developing an irregular pattern with a general trend dipping from the North to the South.

Litostratigrafia do Terciario da região Miranda do Corvo-Viseu (Bacia do Mondego, Portugal)

The lithostratigraphic units (2 groups, 5 formations and 4 members) of the Tertiary of the Miranda do Corvo-Viseu region (Central Portugal) are here described. For each unit the characterization and description (boundaries, diagnostic properties and atributes) were included. The stratigraphic, lithological, sequential and tectonic data allow correlations with other units of the same Tertiary basin located more to west and support the chronostratigraphic attribution. Sedimentologic characteristics of the deposits lead to the interpretation of the influence of tectonism, climate and eustasy during the sedimentary evolution of this Basin.

Transição do enchimento terciário para o encaixe fluvial quaternário na área de Vila Velha de Ródão (sector NE da Bacia do Baixo Tejo)

The geomorphologic characteristics and lithostratigraphic units of the transition from the Tertiary filling stage to the Quaternary fluvial incision in the Vila Velha de Ródão area (Lower Tagus Basin, NE sector) are presented. Several morphodynamic episodes, which had an important tectonic control, were distinguished. The same main morphosedimentary processes can be identified in other areas of this important river basin. Five periods of Quaternary fluvial incision were characterized.

High resolution stratigraphy and miocene facies correlation in Lisbon and Setúbal Peninsula (Lower Tagus basin, Portugal)

Correlation between facies associations (marine, estuarine and distal fluviatile environments) and disconformities, observed between Foz da Fonte (SW of Setúbal Peninsula) and Santa Iria da Azóia (NE of Lisbon) are presented. The precise definition of the marine-continental facies relationships improved very much the chronology of the depositional sequence boundaries. Tectonic and eustatic controls are discussed on the basis of subsidence rates variation.

Evidências geomorfológicas de alguns processos responsáveis pela evolução quaternária do canhão de Setúbal

The deep submarine valley near Setúbal that connects the continental platform to the Tagus Abyssal Plain is a submarine canyon of the type commonly knows as Gouf. In this article we try to show the tectonic influence in its formation and in the installation of its submarine hydrographic net. Some indirect evidences of erosive processes responsible for the formation of typical submarine forms of canyons are analysed based in the interpretation of the batimetric map. Finally, we try to give a brief idea of the evolution of this canyon based on the knowledge that is accepted for the area where he belongs.

Estratigrafia sismica do cenozóico na plataforma continental algarvia: interpretação do controle tectónico da sedimentação

The interpretation of 64 seismic reflection profiles in the Algarve continental platform (36º 20'-37º 00' paralels and 7º 20'-8º 40' meridians) calibrated with five petroleum exploration wells, with the identification of the geometric relations between six Cenozoic seismic units (B to G) and tectonic structures, allowed the construction of sucessive time-isopach maps (twt/s) and detailed interpretation of the geologic evolution. Two major tectonic structures were identified: a) the Portimão-Monchique fracture zone (striking N-S); b) an off-shore NW-SE fault zone, probably the S. Marcos-Quarteira fault. This accident separates two tectonic domains: the western domain (with N-S and E-W predominant structures and, secondarily, NW-SE and NE-SW) and the eastern domain (dominated by WSW-ENE, NW-SE, NE-SW, NNE-SSW and NNW-SSE structures). A persistent halokinetic activity had two major moments: a) sin-C unit; b) sin- and post-E unit. An increasing flexuration of the margin was identified, with spacial and temporal variation of the subsidence. The tectonic regime is considered as generally compressive, but the interpretation of the successíve stress-fields is rendered dificult by the existence of tectonic sub-domains and evaporitic structures.

On the hydrogeology of the Lower Tagus Basin and its Cenozoic geologic evolution

The chemical features of the ground water in the Lower Tagus Cenozoic deposits are strongly influenced by lithology, by the velocity and direction of the water movement as well as by the localization of the recharge and discharge zones. The mineralization varies between 80 and 900 mg/l. It is minimal in the recharge zones and in the Pliocene sand and maximum in the Miocene carbonated and along the alluvial valley. Mineralization always reflects the time of permanence, the temperature and the pressure. The natural process of water mineralization is disturbed in agricultural areas because the saline concentration of the infiltration water exceeds that of the infiltrated rainwater. In the discharge zones, the rise of the more mineralized, some times thermal deep waters related to tectonic accidents give rise to anomalies in the distribution of the aquiferous system mineralization model. The diversity of the hydrochemical facies of the ground water may be related to several factors whose identification is some times difficult.

Adherend thickness effect on the tensile fracture toughness of a structural adhesive using an optical data acquisition method

Adhesive bonding is nowadays a serious candidate to replace methods such as fastening or riveting, because of attractive mechanical properties. As a result, adhesives are being increasingly used in industries such as the automotive, aerospace and construction. Thus, it is highly important to predict the strength of bonded joints to assess the feasibility of joining during the fabrication process of components (e.g. due to complex geometries) or for repairing purposes. This work studies the tensile behaviour of adhesive joints between aluminium adherends considering different values of adherend thickness (h) and the double-cantilever beam (DCB) test. The experimental work consists of the definition of the tensile fracture toughness (GIC) for the different joint configurations. A conventional fracture characterization method was used, together with a J-integral approach, that take into account the plasticity effects occurring in the adhesive layer. An optical measurement method is used for the evaluation of crack tip opening and adherends rotation at the crack tip during the test, supported by a Matlab® sub-routine for the automated extraction of these quantities. As output of this work, a comparative evaluation between bonded systems with different values of adherend thickness is carried out and complete fracture data is provided in tension for the subsequent strength prediction of joints with identical conditions.

From the Bay of Biscay to the High Atlas: completing the anisotropic characterization of the upper mantle beneath the westernmost Mediterranean region

The knowledge of the anisotropic properties beneath the Iberian Peninsula and Northern Morocco has been dramatically improved since late 2007 with the analysis of the data provided by the dense TopoIberia broadband seismic network, the increasing number of permanent stations operating in Morocco, Portugal and Spain, and the contribution of smaller scale/higher resolution experiments. Results from the two first TopoIberia deployments have evidenced a spectacular rotation of the fast polarization direction (FPD) along the Gibraltar Arc, interpreted as an evidence of mantle flow deflected around the high velocity slab beneath the Alboran Sea, and a rather uniform N100 degrees E FPD beneath the central Iberian Variscan Massif, consistent with global mantle flow models taking into account contributions of surface plate motion, density variations and net lithosphere rotation. The results from the last Iberarray deployment presented here, covering the northern part of the Iberian Peninsula, also show a rather uniform FPD orientation close to N100 degrees E, thus confirming the previous interpretation globally relating the anisotropic parameters to the LPO of mantle minerals generated by mantle flow at asthenospheric depths. However, the degree of anisotropy varies significantly, from delay time values of around 0.5 s beneath NW Iberia to values reaching 2.0 sin its NE comer. The anisotropic parameters retrieved from single events providing high quality data also show significant differences for stations located in the Variscan units of NW Iberia, suggesting that the region includes multiple anisotropic layers or complex anisotropy systems. These results allow to complete the map of the anisotropic properties of the westernmost Mediterranean region, which can now be considered as one of best constrained regions worldwide, with more than 300 sites investigated over an area extending from the Bay of Biscay to the Sahara platform. (C) 2015 Elsevier B.V. All rights reserved.

Earthquakes in western Iberia: improving the understanding of lithospheric deformation in a slowly deforming region

Mainland Portugal, on the southwestern edge of the European continent, is located directly north of the boundary between the Eurasian and Nubian plates. It lies in a region of slow lithospheric deformation (< 5 mm yr(-1)), which has generated some of the largest earthquakes in Europe, both intraplate (mainland) and interplate (offshore). Some offshore earthquakes are nucleated on old and cold lithospheric mantle, at depths down to 60 km. The seismicity of mainland Portugal and its adjacent offshore has been repeatedly classified as diffuse. In this paper, we analyse the instrumental earthquake catalogue for western Iberia, which covers the period between 1961 and 2013. Between 2010 and 2012, the catalogue was enriched with data from dense broad-band deployments. We show that although the plate boundary south of Portugal is diffuse, in that deformation is accommodated along several distributed faults rather than along one long linear plate boundary, the seismicity itself is not diffuse. Rather, when located using high-quality data, earthquakes collapse into well-defined clusters and lineations. We identify and characterize the most outstanding clusters and lineations of epicentres and correlate them with geophysical and tectonic features (historical seismicity, topography, geologically mapped faults, Moho depth, free-air gravity, magnetic anomalies and geotectonic units). Both onshore and offshore, clusters and lineations of earthquakes are aligned preferentially NNE-SSW and WNW-ESE. Cumulative seismic moment and epicentre density decrease from south to north, with increasing distance from the plate boundary. Only few earthquake lineations coincide with geologically mapped faults. Clusters and lineations that do not match geologically mapped faults may correspond to previously unmapped faults (e.g. blind faults), rheological boundaries or distributed fracturing inside blocks that are more brittle and therefore break more easily than neighbour blocks. The seismicity map of western Iberia presented in this article opens important questions concerning the regional seismotectonics. This work shows that the study of low-magnitude earthquakes using dense seismic deployments is a powerful tool to study lithospheric deformation in slowly deforming regions, such as western Iberia, where high-magnitude earthquakes occur with long recurrence intervals.

Educating for earthquake science and risk in a tectonically slowly deforming region

Over the past decade, scientists have been called to participate more actively in public education and outreach (E&O). This is particularly true in fields of significant societal impact, such as earthquake science. Local earthquake risk culture plays a role in the way that the public engages in educational efforts. In this article, we describe an adapted E&O program for earthquake science and risk. The program is tailored for a region of slow tectonic deformation, where large earthquakes are extreme events that occur with long return periods. The adapted program has two main goals: (1) to increase the awareness and preparedness of the population to earthquake and related risks (tsunami, liquefaction, fires, etc.), and (2) to increase the quality of earthquake science education, so as to attract talented students to geosciences. Our integrated program relies on activities tuned for different population groups who have different interests and abilities, namely young children, teenagers, young adults, and professionals.

Utilização de métodos ópticos de correlação de imagem para a determinação da tenacidade à fractura de adesivos estruturais

Mestrado em Engenharia Mecânica

Efeitos imediatos da MWM na dor, amplitude de movimento e funcionalidade, na osteoartrite da anca.

Introdução: A mobilização com movimento (MWM), segundo o Conceito Mulligan tem apresentado bons resultados na melhoria da dor, amplitude de movimento e funcionalidade em diversas disfunções. No entanto, existem poucos estudos sobre a articulação da anca e, até este momento, não foi avaliada a sua efetividade em indivíduos com osteoartrite da anca. Objectivo(s): Avaliar os efeitos imediatos da técnica de MWM na dor, na amplitude de movimento e na função física em indivíduos com osteoartrite da anca. Métodos: Foram incluídos 40 participantes com osteoartrite da anca, divididas de forma aleatória em dois grupos (experimental e placebo). Foram avaliadas as amplitudes de movimento de flexão e rotação medial da anca recorrendo ao goniómetro universal, a intensidade da dor através da Escala Numérica da Dor e a funcionalidade através de testes de função física, antes e imediatamente após a intervenção. Para o tratamento estatístico, foi utilizado um nível de significância de 0,05. Resultados: A aplicação de MWM resultou em diferenças significativas, com redução da dor na Escala Numérica da Dor (p=0,005), um aumento de amplitude de movimento de flexão (p=0,001) e de rotação medial (p=0,011), uma diminuição nos tempos dos testes de função física, o teste Timed “Up and Go” (p=0,037) e o teste “40m Self Placed Walk” (p=0,019), e um aumento nas repetições do teste ―30 seg Sit to Stand” (p=0,009), comparativamente ao grupo placebo. Conclusão: Os resultados sugerem que a técnica MWM parece produzir um efeito imediato significativo na diminuição da dor, aumento de amplitude articular e melhoria da função física em indivíduos com osteoartrite da anca. Este efeito foi maior para dor, para as amplitudes de movimento e para o teste de função física - ―30 seg Sit to Stand” quando se analisou a magnitude do efeito.

Efeitos Imediatos da Mobilização com Movimento na Rotação Medial da Gleno-umeral em Jogadores de Andebol

Introdução: No andebol, o ombro é elevado numa amplitude superior a 90º e move-se com elevada velocidade de execução o que pode originar deslocação anterior da cabeça do úmero e diminuição da rotação medial. A técnica MWM pode ser uma mais valia na correção da falha posicional e recuperação da amplitude de movimento de rotação medial da articulação gleno-umeral. Objetivo: Este estudo teve como objetivo verificar os efeitos imediatos da técnica de MWM na amplitude de movimento de rotação medial da articulação gleno-umeral em jogadores de andebol. Métodos: O presente estudo, duplamente cego, é do tipo experimental. Foram incluídos no estudo 30 indivíduos do sexo masculino, jogadores de andebol, distribuídos, aleatoriamente, em dois grupos de 15, experimental e controlo. Em ambos os grupos foi avaliada a amplitude de movimento da rotação medial da gleno-umeral, em dois momentos, pré e pós intervenção. O grupo experimental foi submetido à técnica de MWM no movimento de rotação medial da gleno-umeral no membro dominante. Ao grupo de controlo, foi solicitada a realização do movimento ativo de rotação medial no membro dominante, o fisioterapeuta manteve os mesmos contactos manuais mas não aplicou pressão na cabeça do úmero. Para a comparação entre os grupos experimental e controlo recorreu-se ao teste de Mann-Whitney e para analisar diferenças entre os dois momentos, para cada grupo, foi utilizado o teste de Wilcoxon. Resultados: Foram encontradas diferenças significativas no grupo experimental e controlo, contudo essa diferença foi superior no grupo experimental. Após a intervenção, o grupo experimental apresentou amplitudes de rotação medial da gleno-umeral significativamente mais elevadas às do grupo de controlo (U=0,50; p <0,001). Conclusão: A técnica de MWM para rotação medial produziu um aumento significativo na amplitude desse movimento.