..., mineralogic, fluid inclusion, stable isotope, and other studies were undertaken to illuminate the character and origin of the ores.The deposits consist of a large number of near horizontal, ferberite-bearing quartz veins which cut sharply across the steep bedding and foliation of their Beira Schist host rocks...

... Sr of 0.7136 for the pluton, strongly support the local graywacke-rich Beira Schists as the most likely protolith for this strongly peraluminous granite magma. Geological Society of America 1991 ...

...). along a previously unrecognized shear zone (Fig. 3), here named the Serra da Freita shear zone. This shear zone is coincident with the Porto-Viseu metamorphic belt, characterized by a high temperature low pressure para- genesis of biotite, andalusite/staurolite and sillimanite zones in the Beira Schists...

... indicates median value; open circle indicates outlier value, in the 5% lowest or highest data. Inset: normalization of average values of Tur1a to the Tur1b reference. B. Comparison of trace element distribution (average values) between Panasqueira tourmaline 1a and Beira schists. The elements are arranged...

... consists of vertically foliated biotite-chlorite schists of the Beira group that contain as much as 7 wt% iron oxide and as much as 0.1 wt% manganese oxide ( Polya, 1989 ). Trace metal enrichment of the schist occurs up to several kilometers away from the altered granite cupola ( Polya, 1988...

... of trace elements in the clay fraction. Fieldwork was undertaken in the Nelas/Canas de Senhorim area and covered both banks of the Mondego River, which crosscuts the landscape NE–SW ( Fig. 1 ). The local geology comprises the pre-Ordovician metamorphic series known as the Beira Schist-Greywacke...

... indicate a close temporal relationship between Ordovician tonalitic magmatism and high-grade (low- P ) metamorphism in Iberia. The age obtained for Santa Cruz tonalite (476 ± 1 Ma) represents a constraint on the partial melting event experienced by Ediacaran Schist–Greywacke Complex siliciclastic rocks...

... zircon age distribution between migmatites and the Excomungada Formation from the host Ediacaran–Cambrian Douro–Beiras Supergroup. Although the existence of an inherited zircon population lasting c. 500 Ma, absent in the metasedimentary units, suggests the contribution of Ollo de Sapo magmatic rocks...

...Fernando Nieto Abstract Organic-rich Carboniferous shales with associated coal seams, from the Bacia Carbonífera do Douro-Beira (north Portugal) , have been studied by TEM as well as by a variety of other methods. NH 4 and K micas and berthierine form small subparallel packets of a few layers...

... that some isotopic exchange with the host Beira Schist is required. Finally, as an i formal contribution made possible owing to a last minute change in the programme, H. Gritfitbs (University of Newcastle upon Tyne) presented a review of the extent and nature of carbon isotopic fractionation within modern...

... the basement. The orogen-scale, sinistral Douro–Beira shear zone is supposed to occur along the northern boundary of the Porto–Sátão syncline. As it was not observed in this study it is not marked. ( c ) Lithostratigraphic column of the observed formations. Based on de San Jose et al. (1990) , Gutiérrez...

... muscovite Éléments en trace dans les quartz Datation U-Pb sur Apatite Évolution magmatique-hydrothermale The W-Sn-(Cu) Panasqueira deposit belongs to the Beira Baixa province located in the South of the Serra da Estrela granitic Massif. This region is largely composed of schist greywacke sequence...

... Alonso et al. 2000 ). The complex is mainly composed of S-type granites, diatexites and smaller volumes of metatexites, intruded by post to late kinematic granitoids, and juxtaposed on to the low-grade flyshoid Douro-Beiras Supergroup of Ediacarian to Cambrian age ( Martins et al. 2012 ; Talavera...

.... (ed.) The Ordovician System: Proceedings of a Palaeontological Association symposium, Birmingham, September 1974, University of Wales Press and National Museum of Wales, Cardiff, 359–85 Babin C. Melou M. Mollusques bivalves et brachiopodes des “Schistes de Raguenez” (Ordovicien...

... ( Fig. 1 ) occurs within the Douro-Beiras Carboniferous Trough (DBT), which is located within the Central Iberian Zone, in the Iberian Massif of northwestern Portugal. The DBT strikes northwest–southeast, and is 85 km in length with a width of less than 1 km (e.g., Lemos de Sousa and Wagner 1983...

... pegmatite field are metapelitic mica schists, and rarely, carbonaceous or graphitic schists of upper Ordovician to lower Devonian age ( Ribeiro et al. 2000 ). The region was affected by three phases of the Hercynian orogeny, which led to the S 1 , S 2 and S 3 foliations observed in the field ( Noronha...

... pits and surface galleries. The Castromil-Serra da Quinta gold deposit is an important example of such a mined site; it occurs in the Dúrico-Beirã Au province located in the Central Iberian Zone (CIZ) in the western branch of European Variscan belt, mainly on the eastern flank of the Valongo anticline...

... ). The Queiriga pegmatite field, like other pegmatite occurrences of this area ( e.g. , Penalva do Castelo field: Venturinha beryl-pegmatite, Correia Neves, 1964 ), is located along the border of the large, left-lateral, N130°E-trending Douro-Beira crustal-scale shear zone ( Valle Aguado et al. , 2005 ). We...

... is not much less than from Africa despite a much smaller catchment area, which can be explained by deposition of a conspicuous part of Africa-derived sediment in the Intermediate Basin confined between the Zambezi Shelf, the Beira High, and the Îles Éparses. By assuming that compositional differences between...