New geochemical and isotopic constraints on the genesis of the Oliveira Azeméis granitoid melts (Porto-Tomar Shear Zone, Iberian Variscan Chain, Central-Western Portugal).

The Porto-Tomar Shear Zone (PTSZ) is a very important tectonic structure that separates, in central-western Portugal, two of the major tectonic units of the Iberian Variscan Chain: the Ossa-Morena Zone, to the west, and the Central Iberian Zone, to the east. The Oliveira de Azeméis area lies in the northern sector of the PTZC and it is characterized by the occurrence of strongly deformed granitoids. Country rocks are dominantly pelitic metasediments which, according to recent geological mapping (Pereira et al., 2007), belong to the Precambrian Lourosa Formation and the Ordovician São João de Ver Formation. Using Rb-Sr whole-rock isotopic data, Pinto (1979) proposed an age of 379 12 Ma for the Oliveira de Azeméis granitoids. In this work, new results were obtained on these granitoids in the area between the villages of Travanca and Curval, especially in the Sacramento quarry. In this critical outcrop, strongly deformed two-mica granite (displaying S-C structures, with dextral NNW-SSE shear planes) pass into diatexites and metatexites with garnet, cordierite and sillimanite-bearing melanosomes. Leucosomes seem to have mainly granitic s.s. compositions, but cm-thick bands of leucotonalite were also found. Major element geochemistry of granite samples shows the following ranges: 71.4% SiO2 74.2%; 0.74% Fe2O3t 2.48%; 0.35% MgO 0.60%; 0.49% CaO 1.32%; 2.90% Na2O 3.11%; 4.70% K2O 5.47%; 1.17 ASI 1.36. Trace element data reveal a strong fractionation between highly incompatible LILE and less incompatible HFSE (248 PM normalized Rb/Y 671) and between LREE and HREE (18.6 PM normalized La/Lu 54.7). These features, in particular the peraluminous composition, the high K contents and the distinct rare-earth fractionation suggest that the Oliveira de Azeméis granites are mostly the result of partial melting of metasediments with a large pelitic component and that garnet is a likely residual phase. Isotope geochemistry data show that the previously reported isochron should not correspond to a true age since the 87Sr/86Sr(380Ma) obtained in the granite samples analysed in the present work are very low, varying from 0.6978 to 0.7063, with an average value of 0.7023, which are unrealistic in S-type granitic melts. Probably, the 380 Ma date is the consequence of mixing of different melt source components in the samples used in its calculation. Using the granite whole-rock samples collected in this work, a 328 28 Ma errorchron (MSWD=4.0; initial 87Sr/86Sr=0,7106 0.0045) is now obtained. Assuming a typical syn-tectonic Variscan age of 320 Ma for the studied granites, 87Sr/86Sr and "Nd range from 0.7100 to 0.7133 and from -6.5 to -7.9, respectively. A micaschist sample collected in this area displays 87Sr/86Sr(320Ma) = 0.7146 and "Nd(320Ma) = -9.2. Therefore, the Sr and Nd isotope composition agrees with the clearly dominance of a melt component derived by anatexis of a metapelitic source. Two samples of a garnet-bearing (and comparatively zircon-rich) diatexite show 87Sr/86Sr(320Ma) values (0.7120 and 0.7102) similar to those found in granites, but have higher "Nd(320Ma): -2.0 and -1.6. This may be explained by either (a) the involvement of a different source in the genesis of this diatexite or (b) the occurrence of Nd isotope disequilibrium during the melting process, with the preservation of high 143Nd/144Nd ratios in refractory phases such as garnet and/or zircon. A Rb-Sr wr-feldspar-biotite-muscovite isochron of 301.2 5.6 Ma (MSWD=0.42; initial 87Sr/86Sr=0,71516 0.00074) in a granite sample is interpreted as recording the final stage of the operation of the shear zone, which was accompanied by mica recrystallization. Funding: projects Petrochron (PTDC/CTE-GIX/112561/2009) and Geobiotec (PEst-C/CTE/UI4035/2011). References Pereira E. et allia (2007) – Carta Geológica 1/50000 de Oliveira de Azeméis. INETI, Lisboa. Pinto M.S. (1979) – PhD Thesis. Univ. Leed

Isotopic data from the Pomarinho enclave swarm (SW Iberian Chain)

Mafic microgranular enclaves are a common feature of calc-alkaline granitoids (e.g. tonalites and granodiorites) in active continental margins and collisional orogens. They correspond to dark-coloured globules that, although widespread throughout the host rock, usually constitute only a small proportion of the whole volume of the intrusion. When the enclaves occur strongly concentrated in a restricted area, they form an enclave swarm (e.g. Tobish et al. 1997). At Pomarinho, the Granialpa quarry is a privileged exposure of a cluster of dark igneous enclaves that has been targeted for geochemical and geophysical studies (GeoRadar and AMS). The Pomarinho swarm is located in the SW edge of Évora granitoid (Carvalhosa, 1983), in the Portuguese sector of the Ossa-Morena Zone (Iberian Variscides). The enclaves have tonalitic and granodioritic compositions, whereas the host correspond to a very homogeneous light-coloured granodiorite. Preliminary geochemical information, based on major and trace elements (Moita et al., 2011), suggests that the enclaves and the host rock are probably derived from co-genetic magmas. Rb-Sr isotope data now obtained in four enclaves and three host-rock samples yield an isochron corresponding to 335±14Ma (MSWD=0.96), which fits into the spectrum of ages of the Variscan granitoids in the region. Additionally, the homogeneity of both 87Sr/86Sr335 (0.704758 to 0.705133) and εNd335 (-0.10 to 1.13) values corroborates the hypothesis of derivation of the enclaves and the host granodiorite from a common primitive melt through magmatic differentiation. Low 87Sr/86Sr335 and high εNd335 values suggest that ultimately the parental melt is related to a mantle source, with no or only small contribution of metasedimentary crustal materials

Geochemical signature of the Pomarinho enclave swarm (Ossa-Morena Zone, Portugal)

The enclave swarm of Pomarinho is located in the SW edge of Évora granitoid (Carvalhosa, 1983), in the SW sector of the Ossa-Morena Zone (Iberian Variscides). The Granialpa quarry constitutes a privileged exposure of that swarm and, therefore, it was used to collect samples for AMS, petrographic and geochemical studies. The dominant rock in the quarry is a medium-grained granodiorite, composed of plagioclase, quartz, alkali feldspar and biotite. This granodiorite displays a weak N-S planar anisotropy, de-fined by the arrangement of ferromagnesian minerals (mainly biotite). Dark-colored and fine-grained enclaves, that do not exceed 1% volume of the host rock, can be observed scattered throughout the quarry. However, in the NW part of the quarry, there is a cluster of enclaves which, locally, corre-spond to 40-50% of the volume of the host rock. These enclaves exhibit a significant variability in modal composition and texture; therefore, they constitute a heterogeneous swarm, according to Tobish et al. (1997). The enclaves correspond to tonalites and granodiorites, with either equi-granular or porphyritic textures. Their modal compositions comprise essentially the same minerals found in the host granitoid; the major differences are the higher abundances of biotite and plagioclase and the occurrence of small amounts of hornblende, in the enclaves. AMS measurements on both the enclaves and the host rock are very consistent and show that magnetic lineations (K1) have a N-S trend and a plunge of 36º to the South (Moita et al., 2010). Geochemically, the host granodiorite is very homogeneous considering most of the major elements. It is slightly peraluminous (A/CNK~1.03), corresponding to an I-type granite (White & Chapell, 1977). Regarding trace elements, this granodiorite exhibits negative Nb-Ta anomalies [(Th/Nb)N: 8.59-12.08; (La/Ta)N: 1.73-2.18], slightly LREE-enriched patterns [(La/Lu)N: 12.08-16.43] and negative Eu anomalies (EuN/EuN*: 0.73-0.81). The enclaves may be divided into two groups. The first comprises tonalites with SiO2 from 63% to 65%, MgO from 2.2% to 2.4%, Fe2O3t from 5.1% to 5.8%, CaO from 4.1% to 4.8% and TiO2 from 0.7% to 0.9%. Their A/CNK ratios lie in the range 0.98-1.03 and, therefore, they may be considered metaluminous to weakly peraluminous. The trace element geochemistry, similarly to the host, is characterized by the negative Nb-Ta anomalies [(Th/Nb)N: 4.45-6.86; (La/Ta)N: 2.02-2.65] and the slight enrichment in LREE [(La/Lu)N:9.12-11.38]. The second enclave group, with granodioritic compositions, is always slightly peraluminous (A/CNK ~ 1.05), and has higher SiO2 and lower MgO, Fe2O3, CaO and TiO2 values compared to the tonalitic enclaves. Compared to the host rock, the granodioritic enclaves have higher CaO and Na2O and lower K2O contents. The multi-element patterns of the second enclave group also show negative Nb-Ta anomalies [(Th/Nb)N: 9.55 and 10.88; (La/Ta)N: 1.35 and 1,58] and a small LREE enrichment [(La/Lu)N: 9.48 and 12.86]. This preliminary geochemical information suggests that the enclaves and the host rock are probably derived of co-genetic magmas. In such a picture, the tonalitic enclaves and the host granodiorite should represent different degrees of fractionation from the same parental magmas. The granodioritic enclaves, on the other hand, may represent a strong mechanical interpenetra-tion, but chemically incomplete, of the host granodiorite and the less evolved tonalite. Other da-ta, such as isotope geochemistry (in progress) and AMS information, are expected to bring new light to the discussion on the Pomarinho enclave swarm genesis and evolution

Sr and Nd isotope composition of the Alcáçovas calc-alkaline rocks (Ossa-Morena Zone, Portugal)

The Alcáçovas area is located in the SW sector of the Ossa-Morena Zone (OMZ), close to a major fault that separates this geotectonic unit from the South Portuguese Zone (SPZ). Along this boundary, in the OMZ, testimonies of low-K tholeiitic and calc-alkaline magmatism are common and have been interpreted as being related to the operation of a subduction zone between OMZ and SPZ during the Variscan cycle [1]. Two main igneous lithologies, both displaying calc-alkaline compositions, can be found in the studied area: gabbro-diorites and dacitic-rhyolitic porphyries [2,3]. Outcrop conditions have not yet allowed to establish unequivocally the sequence of magma emplacement. In previous geochronological studies on the porphyries, whole-rock Rb-Sr dates and K-Ar ages cluster around 320 Ma [4,5,6]. According to field observations, sometimes felsic dykes cut mafic rocks, but there are also gradual transitions from gabbroic to tonalitic compositions, within bodies mapped as gabbro-diorite, revealing that different melts coexisted. In this study, rock samples of both gabbro-dioritic bodies and porphyries were analysed for Rb-Sr and Sm-Nd isotopes. Considering the whole set of samples, no isochron was obtained, showing that they can not be simply related by crystal fractionation processes. Rb-Sr data of porphyries from a single quarry (at Lameira, 7 km to the SW of Alcáçovas) give 323±16 Ma (MSWD=1.9; initial 87Sr/86Sr=0.7097±0.0018). Taking into account that the rocks of the Lameira outcrop show strong hydrothermal alteration, this date must be viewed as a consequence of a very efficient redistribution of mobile elements during aqueous fluid circulation and, as such, it places a minimum limit to the actual magmatic age. The plot of compositions of the gabbro-dioritic bodies, including their transitions to tonalites and the associated felsic dykes, in the εNd-87Sr/86Sr diagram, define an almost perfect hyperbole (from εNd323 = +3.9 and 87Sr/86Sr323 = 0.7058 to εNd323 = -3.8 and 87Sr/86Sr323 = 0.7085), as expected in a mixture between mantle-derived melts and crustal materials. In the same diagram, samples from the Lameira quarry show an almost constant εNd323, between -2.4 and -2.9, and 87Sr/86Sr323 varying from 0.7092 to 0.7106. Therefore, the Lameira porphyries could represent a member of the same mixture, with the Sr signature modified by hydrothermal fluids with a stronger crustal component

Tonalitas del Macizo de Hospitais (Zona de Ossa Morena, SO Macizo Ibérico, Portugal): I: Encuadre geológico y petrografía

The Hospitais Massif is an elliptical-shaped plutonic body, with a WNW-ESE long axis, located in the western Ossa-Morena Zone domains in Portugal. This massif, composed essentially of tonalites, is part of an igneous association, ranging from gabbros to granites, intrusive in a gneissic-migmatitic complex, as part of the Évora High-grade Metamorphic Terrains. The tonalites present magmatic fabrics associated with a moderately developed foliation, recording syntectonic crystallization and cooling, co-planar to steep foliations observed within the surrounding sheared gneisses and migmatites. From field and petrographic studies, it is possible to suggest that the deformation of the tonalites and associated basic rocks was synchronous with Variscan progressive shearing of the gneisses and migmatites envelope.El Macizo de Hospitais corresponde a un plutón elíptico de orientación ONO-ESE localizado en los domínios occidentales de la Zona de Ossa Morena, en Portugal. Este macizo, constituido por una asociación ígnea que incluye desde gabros hasta granitos y en la que son dominantes las tonalitas, está intruida en un complejo de gneises y migmatitas perteneciente a los Terrenos de Alto-grado Metamórfico de Évora. Las tonalitas muestran fabricas magmáticas asociadas a una foliación moderadamente desarrollada durante la cristalización y enfriamiento, paralelas a la foliación subvertical observada en los gneises y migmatitas del encajante. Las evidencias de campo y los estudios petrográficos permiten sugerir que la deformación de las tonalitas y rocas básicas asociadas que afloran cerca de Montemor-o-Novo, fue contemporánea con el progresivo cizallamiento Varisco observado en los gneises y migmatitas del encajante

Tonalitas del Macizo de Hospitais (Zona de Ossa Morena, SO Macizo Ibérico, Portugal): II: Geoquímica y petrogénesis

As described in the first part of this work (Moita et al., this volume), the Hospitais Massif belongs to a synorogenic Variscan magmatic association, intrusive in a gneissic-migmatitic complex of the Évora High-Grade Metamorphic Terrains. In this paper, geochemical data obtained on tonalites and dioritic enclaves, from the Hospitais Massif, and on gabbros, from smaller plutonic bodies in the neighbourhood of that massif, are used to constrain hypotheses on the petrogenetic processes responsible for the mentioned lithologies. Major and trace element geochemistry reveal calc-alkaline affinities and suggest that gabbros, diorites and tonalites belong to a magma suite derived dominantly by fractional crystallization. The presence of microgranular mafic enclaves, within the tonalites, could be interpreted as representing an additional process of mingling/mixing for the evolution of these rocks. According to their geochemical features, the enclaves may have resulted from an intermediate differentiation product internally mixed with the tonalite melt. A filter-pressing process can explain the amphibole-dominated cumulate REE pattern displayed by the enclaves.Como se ha descrito en la primera parte del trabajo (Moita et al. en este volumen), el Macizo de Hospitais pertenece a una serie magmática sinorogénica Varisca intruida en un complejo de gneises y migmatitas perteneciente a los Terrenos de Alto-grado Metamórfico de Évora. Se han utilizado datos geoquímicos de las tonalitas, de los enclaves dioríticos y de pequeños cuerpos, espacialmente asociados, de gabro, para caracterizar los procesos petrogenéticos relacionados con esta serie magmática. La geoquímica de elementos mayores y traza muestra una afinidad calco-alcalina y sugiere que los gabros, dioritas y tonalitas pertenecen a una serie magmática originada mediante procesos de cristalización fraccionada. La presencia de enclaves microgranulares máficos en tonalitas, puede ser interpretada como el resultado de un proceso adicional de “mingling/mixing” en la evolución en estas rocas. De acuerdo con sus características geoquímicas los enclaves serián el resultado de un producto intermedio de diferenciación internamente mezclado con el magma tonalítico. Un proceso de “filter-pressing” puede explicar los patrones de tierras raras de cumulados anfibólicos característicos de los enclaves estudiados

Pomarinho enclave swarm (Évora granitoid): a preliminary study

No bordo SW do granitóide de Évora (junto a Pomarinho), encontra-se um enxame de encraves ígneos, máficos a intermédios. Dados de ASM, obtidos nos encraves e na rocha hospedeira, revelam uma forte coerência nas lineações magnéticas (K1), com direcção N-S e inclinação de 35º para S. Estes resultados permitem sugerir que a disposição das lineações tivesse sido controlada por factores como: i) reajustamento tectónico nas fases finais da cristalização magmática; ii) forte influência do bordo lateral da intrusão (N-S); iii) fluxo simultâneo dos magmas félsico e máfico próximo do topo da intrusão.A swarm of mafic to intermediate igneous enclaves can be observed in the SW border of the Évora granitoid, near Pomarinho. AMS measurements, on both the enclaves and the host rock are very consistent and show that magnetic lineations (K1) have a N-S trend and a plunge of 36º to the S. The attitude of the studied linear features could have been controlled by: i) the tectonic stress field, during the final stages of igneous crystallization; ii) the orientation of the wall of the intrusion; iii) the simultaneous flow of the felsic and mafic magmas close to the top of the intrusion

Disease tolerance and immunity in host protection against infection

The deposited article is a pre-print version.This publication hasn't any creative commons license associated.This deposit is composed by the main article which contains attached the supplementary materials.The immune system probably evolved to limit the negative effects exerted by pathogens on host homeostasis. This defence strategy relies on the concerted action of innate and adaptive components of the immune system, which sense and target pathogens for containment, destruction or expulsion. Resistance to infection refers to these immune functions, which reduce the pathogen load of an infected host as the means to preserve homeostasis. Immune-driven resistance to infection is coupled to an additional, and arguably as important, defence strategy that limits the extent of dysfunction imposed on host parenchymal tissues during infection, without exerting a direct negative effect on pathogens. This defence strategy, known as disease tolerance, relies on tissue damage control mechanisms that prevent the deleterious effects of pathogens and that uncouples immune-driven resistance mechanisms from immunopathology and disease. In this Review, we provide a unifying view of resistance and disease tolerance in the framework of immunity to infection.Instituto Gulbenkian de Ciência; Fundação Calouste Gulbenkian; Fundação para a Ciência e Tecnologia grants: (PTDC/SAU-TOX/116627/2010, HMSP-ICT/0022/2010, PTDC/BEX-GMG/3128/2014); ERC grants: (ERC-2011-AdG 294709-DAMAGECONTROL, ERC-2014-CoG 647888-iPROTECTION).info:eu-repo/semantics/publishedVersio

Optimal design of thin-walled laminated beams with geometrically nonlinear behaviour

Com o apoio RAADRI.The purpose of this paper is to present a finite element model for optimal design of composite laminated thin-walled beam structures, with geometrically nonlinear behaviour, including post-critical behaviour and accounting warping deformation. A general continuum formulation is presented for the structural nonlinear analysis, based on the virtual work principle, and using the Updated Lagrangean procedure to describe the deformation of the structure. In order of defining the post-critical behaviour, a generalized displacement control method has been implemented. The thin-walled beam cross-section is considered as made from an assembly of flat layered laminated composite panels. The cross-section bending-torsion properties are integrals based on the cross-section geometry, on the warping function and on the individual stiffness of the laminates that constitute the cross-section. In order to determine its bending-torsion properties, the cross-section geometry is discretized by quadratic isoparametric finite elements. Along its axial direction, the beam is modelled throughout two-node Hermitean finite elements with seven degrees-of-freedom a node. Design sensitivities are imbedded into the finite element modelling and assembled in order to perform the design sensitivity analysis of various structural performance measures by using the adjoint method. As design variables one considers laminate thickness, lamina orientations and the global cross-section geometry. This geometry is defined by the position of master nodes related to the cross-section finite element mesh. Design optimization is performed throughout nonlinear programming techniques

Limiting performance analisys of a head protection helmet using multicriteria control optimization

In this paper the limiting performance analysis of a head protection helmet is performed. A discrete model of the human head is used. A multicriteria optimum control problem is formulated in order to minimize the risk of injuries in case of impact. Several injury criteria are minimized and are required to remain below a safety threshold value. The optimal control force acting on the head is found. The optimal control force is determined by nonlinear programming. The equations of motion are integrated at-once, as it is typical for static response, instead of the traditional step-by-step integration.info:eu-repo/semantics/publishedVersio