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In the Central Iberian Zone, multiple subvolcanic intrusions were emplaced during the final stages of the Variscan orogeny. The felsic component of this magmatic episode is mainly represented by dykes and masses of granite porphyries and microgranites, which can be commonly found in northern Portugal. Overall, these rocks are more evolved and enriched in rare incompatible metal elements (such as Li, Be, Rb, Cs, Nb, Ta, Sn, and W) when compared to the regional Variscan granites. The data acquired from the lithogeoc...

This work is a mineral chemistry study of the pyroxene crystals composing a microgabbro dyke found in the Vila Nova de Foz Coa (VNFC) region of northern Portugal. Several pyroxene geothermometers and geobarometers have also been employed to infer the likeliest thermodynamic conditions of crystallization. Following the IMA 1988 report for the nomenclature of pyroxene minerals, the VNFC microgabbro is rich in Ca-Mg-Fe species. The studied clinopyroxenes are aluminian, chromian, and/or ferroan diopside and augite, wh...

Multiple veins of subvolcanic lithologies, including porphyries, lamprophyres and dolerites, outcrop in northern Portugal intruding both the pre-variscan metasedimentary basement (known as the Schist-Greywacke Complex) and variscan granites of high compositional variability. The N-S trending, granitic/rhyolitic porphyries of Vila Pouca de Aguiar (VPA) constitute two of the most important examples of these veins. Both porphyries intrude the main facies of the regional pluton (the VPA granite). The present study con...

The aim of this study is to contribute to the detection and identification of hydrothermal alteration zones in Variscan granites using magnetic susceptibility. The studied area is located in the North-western of Portugal and is characterised by the occurrence of Au mineralizations in quartz veins hosted in Variscan granites. Three different granite facies were studied, using two methodologies: (i) measurements, in situ, of magnetic susceptibility using a portable susceptibility meter (TerraPlus KT-10), allowing th...

The present work shows some results obtained by the Time-Domain Electromagnetic Method (TDEM) to help characterize the geology and Penacova- RпїЅgua-Verin fault structure in the Vila Pouca de Aguiar sector. The Fault is an important tardi-variscan structure with NNE-SSW direction, more than 500 km long, extending from the North of Spain until near NazarпїЅ. The application of the TDEM method aimed to acquire data towards obtaining profiles of subsurface electrical resistivity in the zone affected by the fault and ...