Multidisciplinary study of Santa Eulália Plutonic Complex (Central Portugal): Preliminary insight.

Multidisciplinary study of Santa Eulalia Plutonic Complex (Central Portugal): Preliminary insight H. SANT’OVAIA1*, J. CARRILHO LOPES2 AND P. NOGUEIRA2 1DGAOT, Centro de Geologia, FCUP, Portugal (*correspondence: [email protected]) 2Dep. Geo., Univ. Évora, Centro de Geologia UL, Portugal The Santa Eulália Plutonic Complex (SEPC) is a late- Variscan calcalkaline granitic body that occupies an area of 400 km2 and is located in the Variscan Iberian sector. The host rocks of the complex are composed by metamorphic formations from Proterozoic to Lower Paleozoic. The SEPC has two main facies which present different compositions and textures. From the rim to the core, there is a medium- to coarse-grained pinkish granite (G0) involving large masses of mafic to intermediate rocks and a central gray monzonitic granite (G1). The central facies can be divided into a porphyritic facies (G1A) and a central medium-grained facies (G1B). Multidisciplinary studies that include petrography, mineral and whole-rock chemistry, Anisotropy of Magnetic Susceptibility (AMS) and microstructural analyses were carried out. Besides petrographic and mineral chemistry data, whole-rock analytical results reveal clear differences between these two main granitic facies. G0 granites represent more evolved liquids (>SiO2 wt.% and <MgO wt.%), plot closer to metaluminous and A-type fields, and present negative Eu anomalies, while G1 facies are typically monzonitic granites with a strong peraluminous character. The AMS study was based on 50 sampling sites. The magnetic susceptibility ranges between 55.09 and 7343.67 x 10-6 SI. Two major groups can be established: facies G0, with Km > 10-3 SI which supports the presence of magnetite, and the central facies (G1A, G1B) with Km< 10-4 SI. In the central facies the paramagnetic behaviour is due to ferromagnesian minerals, such as biotite, and ilmenite. Magnetic anisotropy ranges between 2.2 and 18.2% being in mean >5% in facies G0 and <4% in the central facies. The high P% in G0 facies may be caused by the magnetic bearer, magnetite. Nevertheless, microscope observations show signs of a post-magmatic deformation in G0. These preliminary data support that the facies G0 and the central facies (G1) have a distinct magnetic behaviour which may suggest different redox conditions in magma genesis. This work has been financially supported by PTDC/CTEGIX/ 099447/2008 (FCT-Portugal, COMPETE/FEDER)

Los efectos térmicos del Complejo Plutónico de Santa Eulalia (sur de Portugal) en las rocas metaígneas y metasedimentarias encajantes

The Santa Eulália Plutonic Complex (SEPC) is a late-Variscan granitic body located in the northern part of the Ossa Morena Zone, a inner zone of the Variscan Iberian Massif. The SEPC host rocks are composed of meta-igneous and metasedimentary units, from Upper Proterozoic to Paleozoic ages, with a NW-SE structure, cross-cut by the SEPC. The SEPC host rocks, with low grade metamorphism show well preserved primary sedimentary or igneous mineralogical, textural and structural features. The thermal effect induced by the SEPC is restricted to the roof pendants. At N and NE of the SEPC, textures and paragenesis resulting from thermal metamorphism, are not related to the SEPC intrusion but to a previous magmatism, controlled by the NW-SE regional anisotropies. The restriction of the thermal effects to the pluton roof may be caused by a combination of several interrelated factors: higher volume of granitic mass, thermal effect by advection of fluids and longer period of prevalence of high thermal conditions. The geochemical study of SEPC host rocks shows the heterogeneous character and diversity of metasedimentary, igneous and meta-igneous rocks. The whole rock geochemical data indicate that all the metasedimentary lithologies derived from an upper continental crustal source and the igneous and meta-igneous rocks show no evidence of metasomatic effects by the SEPC emplacement.El Complejo Plutónico de Santa Eulalia (CPSE) es un cuerpo granítico tardi-Varisco situado en la parte norte de la Zona de Ossa Morena, en la zona interior del Macizo Ibérico Varisco. Las rocas encajantes del CPSE están compuestas por unidades meta-ígneas y metasedimentarias, de edades que van desde el Proterozoico Superior hasta el Paleozoico, con una estructura de dirección NW-SE, cortada por el CPSE. Las rocas encanjantes del CPSE, con metamorfismo de bajo grado conservan estructuras, mineralogía y textura primarias. El efecto térmicoinducido por el CPSE se limita a los roof pendants. Al N y NE del CPSE, las texturas y paragénesis resultantes del metamorfismo térmico, no están relacionadas con la intrusión del CPSE sino con un magmatismo anterior, controlado por anisotropías regionales NW- SE. La restricción de los efectos térmicos al techo del pluton puede ser causada por una combinación de varios factores interrelacionados: mayor volumen de masa granítica, un efecto térmico por la advección de fluidos y el período de prevalencia de altas condiciones térmicas. Los datos geoquímicos de las rocas encanjantes del CPSE muestran el carácter heterogéneo y la diversidad de rocas sedimentarias, metasedimentarias, ígneas y meta-ígneas. El análisis de los datos geoquímicos indica que todas las litologías sedimentarias y metasedimentarias han derivado de la corteza continental superior, mientras las rocas ígneas y meta-ígneas tienen una composición que no muestra evidencias de efectos metasomáticos por el emplazamiento del CPSE

AMS and IRM studies in the late-variscan Santa Eulália Plutonic Complex (Ossa-Morena Zone, Portugal)

The Santa Eulália Plutonic Complex (SEPC) is a calc-alkaline granitic body, with an area of 400 km2, and is located in the north of the Ossa Morena Zone of the Variscan Iberian sector, near the limit with the Central Iberian Zone. SEPC is considered late-Variscan because it cross-cuts the regional variscan structures. The host rocks are metamorphic formations from Upper Proterozoic to Lower Paleozoic. The SEPC has two main granitic facies with different compositions and textures. From the rim to the core, there is a medium-to coarse-grained pink granite (G0), which involves large elongated masses of mafic to intermediate rocks (M); and a central grey monzonitic granite (G1) which presents a dominant medium granular facies, and also a slight porphyritic texture close to G0. AMS and IRM studies were conducted to characterise these rocks, from 61 sampling sites: 29 in G0, 27 in G1 and 5 in M. The Km values range between 41.6 and 7343.7 x 10-6 SI in granitic rocks: G0, with Km > 10-3 SI (mean: 1357.4 x 10-6 SI) which supports the presence of magnetite, and G1 with Km< 10-4 SI (mean: 97.0 x 10-6 SI). In M, Km values are homogeneous with a mean of 620.9 x 10-6 SI. The magnetic anisotropy (P%) and the ellipsoid shape (T) were only determined in granites. The mean values of P% are 6.2% and 3.1% in G0 and G1, respectively. T shows the strongest oblate ellipsoids in central G1 (mean: 0.365) and slightly oblate in G0 (mean: 0.099). The magnetic foliations are subvertical ENE-WSW-striking in G0 and G1. Magnetic lineations are subvertical in G0 and moderately plunge to the SE in G1.The saturation IRM (SIRM) mean values are 9.345 A/m in G0, 0.027 A/m in G1 and 2.634 A/m in M. In G0 and M, the IRM acquisition curves show saturation between 0.3 and 0.4 T, followed by a small increase in increasing fields, suggesting that the main carrier of remanence is low magnetite or Ti-magnetite. In G1, the acquisition curves demonstrate paramagnetic and antiferromagnetic fractions, but a small magnetite fraction can also be present. SIRM/K have mean values of 7.119 kA/m, 0.298 kA/m and 3.425 kA/m for Go, G1 and M, respectively. The AMS and SIRM data support that G0 and G1 have a distinct magnetic behaviour. G0 is controlled by a ferrimagnetic fraction. G1, with Km< 10-4 SI, shows a paramagnetic behaviour due to ferromagnesian minerals, such as biotite and ilmenite. In M, Km is typical of gabbros and granodiorites and is due to the high contents of ferromagnesian minerals. The magnetic behaviours of G0 and G1 suggest different redox conditions in the magma genesis. Magnetic anisotropy is higher in G0 due to the presence of magnetite, but microscope observations also show signs of a post-magmatic deformation in G0. Although magnetic foliations are subvertical ENE-WSW-striking in both granites, magnetic lineations are different. The differences reflect distinct redox processes at magmatic sources and different emplacement mechanisms of M, G0 and G1

Púrpura de Henoch Schonlein : a propósito de um caso clínico

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2021A Púrpura de Henoch Schonlein (PHS) é uma vasculite sistémica leucocitoclástica de pequenos vasos, mediada por Imunoglobulina A, que leva à deposição de imunocomplexos a nível vascular. É a forma mais comum de vasculite sistémica na idade pediátrica, com um pico de incidência entre os 5 e 7 anos. Nesta patologia, para além da presença de manifestações cutâneas, com o aparecimento de púrpura palpável, surgem também frequentemente manifestações articulares, gastrointestinais e renais. A maioria das situações é autolimitada, requerendo apenas terapia de suporte. No entanto, em alguns casos, devido à persistência das manifestações ou surgimento de complicações, nomeadamente a nível gastrointestinal, é necessário recorrer a outras terapêuticas alternativas, como corticoesteróides ou agentes imunossupressores. No presente trabalho, é analisado um caso clínico de uma criança de 5 anos, diagnosticada com púrpura de Henoch Schonlein, cujo sintoma inaugural foi a dor abdominal. Durante o internamento, destaca-se o agravamento desta dor, refratária à analgesia endovenosa e o desenvolvimento de invaginação intestinal. O objetivo deste trabalho consiste em fazer uma revisão teórica sobre púrpura de Henoch Schonlein, com especial destaque nas manifestações e complicações gastrointestinais decorrentes da doença e, com base no caso clínico, discutir a abordagem terapêutica neste tipo de casos.Henoch Schonlein Purpura (HSP) is a leukocytoclastic systemic vasculitis of small vessels, mediated by Immunoglobulin A, which leads to the deposition of immune complexes at the vascular level with subsequent leukocyte involvement. It is the most common form of systemic vasculitis in pediatric age, with a peak incidence between 5 and 7 years. In this pathology, in addition to the presence of cutaneous manifestations, with the appearance of palpable purpura, joint, gastrointestinal and renal manifestations also frequently appear. Most situations are self-limited, requiring only supportive therapy. However, in some cases, due to the persistence of manifestations or the appearance of complications, particularly at the gastrointestinal level, it is necessary to resort to other therapeutic alternatives, such as corticosteroids or immunosuppressive agents. In the present study, it is analysed a clinical case of a 5-year-old child, diagnosed with Henoch Schonlein purpura, whose inaugural symptom was the presence of abdominal pain. During hospitalization, the worsening of this pain stands out, with resistance to intravenous analgesia and the development of an intestinal intussusception. The objective of this work is to make a theoretical review of Henoch Schonlein purpura, with special emphasis on gastrointestinal manifestations and complications resulting from the disease and, based on the clinical case, to discuss the therapeutic approach in these types of cases

Geothermal resources research in a granitic basement - the Braga area case study (NW Portugal)

Geothermal resources are increasingly being considered as a strategic alternative in energy production, especially with the latest geopolitical developments. The densely populated Braga region, in NW Portugal, is endowed with a geostructural setting that enables the existence of several thermal water occurrences, spatially associated with a deep-rooted structure – the Vigo-Régua shear zone, set in a granite context. Given the latest advances in geothermal energy production, it is possible to predict a mid- to long-term implementation of geothermal energy production in the vicinity of that deep rooted structure. Although strongly encouraging, the exploratory geophysical, geochemical and geological data are still insufficient to deliver a definitive frame of the potential energy associated with the estimated reservoirs. Ongoing work combining gravimetric, radiometric and geochemical data will provide a better understanding of the deeply concealed structures.Les ressources géothermiques sont de plus en plus considérées comme une alternative stratégique dans la production d'énergie, en particulier compte tenu du contexte géopolitique récent. La région densément peuplée de Braga, au nord-ouest du Portugal, est située dans un contexte granitique spatialement associé à une structure enracinée - la zone de cisaillement Vigo-Régua. Ce contexte géologique et structural a permis le développement de plusieurs occurrences d'eau thermale. Compte tenu des dernières avancées en matière de production d'énergie géothermique, il est possible de prévoir une mise en œuvre à moyen et long terme de la production d'énergie géothermique à proximité de cette structure profonde. Bien que fortement encourageantes, les données géophysiques, géochimiques et géologiques exploratoires sont encore insuffisantes pour fournir un cadre définitif de l'énergie potentielle associée aux réservoirs estimés. Des travaux en cours combinant des données gravimétriques, radiométriques et géochimiques permettront de mieux comprendre les structures profondément enfouies.Los recursos geotérmicos se consideran cada vez más como una alternativa estratégica en la producción de energía, especialmente con los últimos desarrollos geopolíticos. La región densamente poblada de Braga, en el noroeste de Portugal, está dotada de un entorno estructural que permite la presencia de aguas termales, asociadas espacialmente con una estructura profunda en un contexto granítico: la zona de falla Vigo-Régua. Dados los últimos avances en la producción de energía geotérmica, es posible predecir una implementación a mediano y largo plazo de la producción de energía geotérmica en las cercanías de esa estructura de raíces profundas. Aún cuando los datos geofísicos, geoquímicos y geológicos exploratorios son muy alentadores, son insuficientes para brindar un marco definitivo del potencial geotérmico asociada con los yacimientos. El trabajo en curso que integra datos gravimétricos, radiométricos y geoquímicos proporcionará una mejor comprensión de las estructuras profundas por explorar

Petrogenetic constraints on the felsic vein magmatism in northern Portugal based on petrological and geochemical data

Three of the largest granite porphyries of northern Portugal were studied to improve current knowledge on the regional felsic vein hypabyssal magmatism. All porphyries exhibit microcrystalline groundmasses of variable granularity (composed of quartz, K-feldspar, and muscovite), quartz, K-feldspar, plagioclase, biotite, and cordierite phenocrysts, antirapakivi and rapakivi feldspars, embayments in quartz, and enrichments in rare metal incompatible elements. The veins were emplaced along fractures generated during the last phase of the Variscan orogeny. Textural features were presumably conditioned by fast cooling, volatile loss, subsolidus annealing, and the magnitude of thermal contrasts at the time of emplacement. All veins were altered by subsolidus hydrothermal fluids, as suggested by several petrographic and geochemical evidence. The generation of mantled feldspars is probably related to isothermal decompression and magma mixing, which is compatible with the $\varepsilon \mathrm{Nd}_{i}$ signatures (${-}3.76$ to ${-}4.40$). Based on this research, both processes have contributed to the petrogenesis of the studied porphyries

Petrogenetic constraints on the felsic vein magmatism in northern Portugal based on petrological and geochemical data

Three of the largest granite porphyries of northern Portugal were studied to improve current knowledge on the regional felsic vein hypabyssal magmatism. All porphyries exhibit microcrystalline groundmasses of variable granularity (composed of quartz, K-feldspar, and muscovite), quartz, K-feldspar, plagioclase, biotite, and cordierite phenocrysts, antirapakivi and rapakivi feldspars, embayments in quartz, and enrichments in rare metal incompatible elements. The veins were emplaced along fractures generated during the last phase of the Variscan orogeny. Textural features were presumably conditioned by fast cooling, volatile loss, subsolidus annealing, and the magnitude of thermal contrasts at the time of emplacement. All veins were altered by subsolidus hydrothermal fluids, as suggested by several petrographic and geochemical evidence. The generation of mantled feldspars is probably related to isothermal decompression and magma mixing, which is compatible with the $\varepsilon \mathrm{Nd}_{i}$ signatures (${-}3.76$ to ${-}4.40$). Based on this research, both processes have contributed to the petrogenesis of the studied porphyries

Multivariate analysis applied to X-ray fluorescence to assess soil contamination pathways: case studies of mass magnetic susceptibility in soils near abandoned coal and W/Sn mines

Determining the origin and pathways of contaminants in the natural environment is key to informing any mitigation process. The mass magnetic susceptibility of soils allows a rapid method to measure the concentration of magnetic minerals, derived from anthropogenic activities such as mining or industrial processes, i.e., smelting metals (technogenic origin), or from the local bedrock (of geogenic origin). This is especially effective when combined with rapid geochemical analyses of soils. The use of multivariate analysis (MVA) elucidates complex multiple-component relationships between soil geochemistry and magnetic susceptibility. In the case of soil mining sites, X-ray fluorescence (XRF) spectroscopic data of soils contaminated by mine waste shows statistically significant relationships between magnetic susceptibility and some base metal species (e.g., Fe, Pb, Zn, etc.). Here, we show how qualitative and quantitative MVA methodologies can be used to assess soil contamination pathways using mass magnetic susceptibility and XRF spectra of soils near abandoned coal and W/Sn mines (NW Portugal). Principal component analysis (PCA) showed how the first two primary components (PC-1 + PC-2) explained 94% of the sample variability, grouped them according to their geochemistry and magnetic susceptibility in to geogenic and technogenic groups. Regression analyses showed a strong positive correlation (R2 > 0.95) between soil geochemistry and magnetic properties at the local scale. These parameters provided an insight into the multi-element variables that control magnetic susceptibility and indicated the possibility of efficient assessment of potentially contaminated sites through mass-specific soil magnetism

The national inventory of geological heritage: methodological approach and results

A existência de um inventário nacional de património geológico é fundamental para se poderem implementar estratégias de geoconservação. Este trabalho apresenta a metodologia usada no desenvolvimento do mais completo inventário de geossítios, realizado até ao momento em Portugal, assim como os principais resultados obtidos. O inventário vai integrar o Sistema de Informação do Património Natural e o Cadastro Nacional dos Valores Naturais Classificados, ambos geridos pelo Instituto de Conservação da Natureza e da Biodiversidade.The existence of a national inventory of the geological heritage is of paramount importance for the implementation of a geoconservation strategy. This paper presents the methodological approach used to produce the most complete geosites inventory in Portugal, so far, and the obtained results. This inventory will be uploaded into the National Database of Natural Heritage managed by the Portuguese authority for nature conservation.Este trabalho é apoiado pela Fundação para a Ciência e a Tecnologia, através do financiamento plurianual do CGUP e do projecto de investigação “Identificação, caracterização e conservação do património geológico: uma estratégia de geoconservação para Portugal” (PTDC/CTE-GEX/64966/2006).info:eu-repo/semantics/publishedVersio