151 documents found, page 1 of 16
Ranked Mappable Criteria for Magmatic Units: Systematization of the Ossa-Morena...
Roseiro, José; Moreira, Noel; de Oliveira, Daniel; Silva, Marcelo; Eguiluz, Luis; Nogueira, PedroThe Ossa-Morena Zone (SW Iberian Massif) hosts the largest set of Cambro–Ordovician alkaline magmatic plutons related to the Palaeozoic rifting of the northern Gondwana margin so far described. An organized framework for their classification at different scales is proposed through data-driven ranks based on their distinctive petrological features relative to other rift-related magmatic rocks found throughout we...
High strain peralkaline orthogneisses within orogenic scale shear zones: geolog...
Roseiro, José; Moreira, Noel; Nogueira, Pedro; de Oliveira, DanielThe lithological units in the Arronches region (included within the Arronches tectonic unit, Tomar-Badajoz-Córdoba Shear Zone, northernmost Ossa-Morena Zone) and in particular the peralkaline orthogneisses therein, have been the target for petrological, geochemical and structural studies in order to constrain its petrogenesis and tectono-metamorphic contextualization within the broader regional geology. Two det...
Architecture of a (deformed) rift-related basin: new insights about the Cambria...
Moreira, Noel; Roseiro, José; Nogueira, PedroThe Ossa-Morena Zone (OMZ) is the outermost domain of the Iberian Massif hinterland and presents a stratigraphic succession which records the process of rifting that occurs in the northern Gondwana margin, leading to the opening of the Rheic Ocean during Cambrian-Ordovician times. Although this zone has witnessed a complex tectono-metamorphic evolution during Devonian-Carboniferous times, related to the rise up...
Variscan tectono-metamorphic recrystallization of Cambro-Ordovician feldspathic...
Roseiro, José; Moreira, Noel; de Oliveira, Daniel; Nogueira, PedroThe alkaline magmatic rocks emplaced during the Cambro-Ordovician rifting of north Gondwana consist of alkaline granites, syenites and albitites variably deformed during the Variscan Orogeny. They are located in in the central-northern domains of the Ossa-Morena Zone (SW Iberia), within areas that experienced varying tectono-metamorphic conditions during the late Palaeozoic, ranging from low-grade to high-grade...
Strain partitioning in transpression; a major feature in the evolution of the I...
Dias, Rui; Araújo, Alexandre; Couto, Helena; Cruz, Cláudia; Ferreira, Joana; Gonçalves, Ana Marta; Lima, Alexandre; Lopes, Luís; Moreira, NoelAs the wavy pattern of fold belts is a common feature, since its recognition, the transpressive regimes were expected to be a pervasive mechanism on their evolution. Nevertheless, even in regions where oblique shortening is inferred, typical structures of transpression (e.g. transected cleavage and en echelon folds, shear or veins) are often absent. Instead, what is frequently observed is the juxtaposition of n...
Mineralogical and geochemical characterization of surface soils and waste piles...
André da Silva Costa, Óscar Filipe; Reis, Amelia; Nogueira, Pedro; Simões, Pedro Pimenta; Kumoleha, A.ABSTRACT: The Preguiça and Vila Ruiva mines, located in the Ossa Morena Zone, Beja district, were explored for Fe-Zn-Pb in the early and mid-20th century. This study aims to reassess their mining potential by creating geochemical maps using modern exploration techniques combined with petrographic and mineralogical analyses. These maps resulted from field measurements obtained by portable X-ray fluorescence (XRF...
High strain peralkaline orthogneisses within orogenic scale shear zones: geolog...
Roseiro, José; Moreira, Noel; Nogueira, Pedro; de Oliveira, Daniel Pipa SoaresABSTRACT: The lithological units in the Arronches region (included within the Arronches tectonic unit, Tomar-Badajoz-Córdoba Shear Zone, northernmost Ossa-Morena Zone) and in particular the peralkaline orthogneisses therein, have been the target for petrological, geochemical and structural studies in order to constrain its petrogenesis and tectono-metamorphic contextualization within the broader regional geolog...
Ranked Mappable Criteria for Magmatic Units: Systematization of the Ossa-Morena...
Roseiro, José; Moreira, Noel; de Oliveira, Daniel Pipa Soares; Silva, Marcelo; Eguiluz, Luis; Nogueira, PedroABSTRACT: The Ossa-Morena Zone (SW Iberian Massif) hosts the largest set of Cambro-Ordovician alkaline magmatic plutons related to the Palaeozoic rifting of the northern Gondwana margin so far described. An organized framework for their classification at different scales is proposed through data-driven ranks based on their distinctive petrological features relative to other rift-related magmatic rocks found thr...
Life on Mars? Contaminação por Metais na Mina do Trimpancho
Nogueira, Pedro; Roseiro, José; Silva, Marcelo; Onyealisi, Obinna; Araujo, Joana; Silva, Roberto; São Pedro, Diogo; Araujo, Alexandre; Fonseca, RitaA Faixa Piritosa Ibérica constitui uma das províncias metalogenéticas mais relevantes da Europa, caracterizada por mineralizações de sulfuretos maciços e um longo historial de atividade mineira. A mina do Trimpancho, situada na zona fronteiriça entre Portugal e Espanha, integra este contexto geológico e apresenta vestígios de exploração antiga, com escombreiras remanescentes que constituem fontes de contaminaçã...
Golden Years: Mineralogical associations in the Casa-Novas orogenic gold deposi...
Nogueira, Pedro; São Pedro, Diogo; Roseiro, José; Sant'Ovaia, HelenaGold mineralisations are frequently associated with orogenic belts where accretionary and collisional processes create favourable conditions for mineral deposit formation. These belts, subject to metamorphism and deformation, host significant gold resources in structurally controlled hydrothermal systems. Among the various models explaining gold transport and deposition, the role of bismuth (Bi)-rich fluids has...