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Contribuição dos sistemas isotópicos Sm-Nd e Rb-Sr para o estudo petrogenético ...
Almeida, A.; Santos, J. F.; Noronha, F.O Granito do Porto corresponde a um granito hercínico, leucocrata, de duas micas, fortemente peraluminoso. No presente trabalho foram realizadas análises para os sistemas isotópicos Rb-Sr e Sm-Nd, em cinco amostras frescas do granito em estudo. Obteve-se uma isócrona Rb-Sr de 306±7 Ma (MSWD=0,71; 87Sr/86Sr inicial=0,7128), que dentro da margem de erro, deverá refletir a instalação magmática. Em termos de geoquí...
Sequência de processos anatéticos no Complexo Migmatítico de Mindelo (NW de Por...
Areias, M.; Ribeiro, M. A.; Santos, J. F.; Dória, A.O Complexo Migmatítico de Mindelo aflora na orla litoral a norte do Porto sendo composto por um conjunto de litologias diversas incluindo rochas metassedimentares, migmatíticas, graníticas e veios pegmatíticos. As relações de campo, petrografia, geoquímica e assinatura isotópica das diversas litologias permitem deduzir a sequência de processos anatéticos que resultaram na heterogeneidade litológica presente. A ...
Petrography, geochemistry and tectonic significance of the Mahoor granitoids (L...
Miri Beydokhti, R.; Karimpour, M. H.; Mazaheri, S. A.; Santos, J. F.The Mahoor granitoids are Cu–Zn-bearing porphyries that outcrop in the central part of the Lut Block, about 135 km south-west of Nehbandan (eastern Iran). These granitoids occur mainly as dykes and stocks that intrude Eocene volcanics. Petrographically, all the studied intrusives display porphyritic textures with mm-sized phenocrysts, most commonly of plagioclase and hornblende, embedded in a fine-grained groun...
Sedimentary climatic record in the Galician Internal Basin: sediment provenance...
Plaza Morlote, M.; Bernabeu, A. M.; Benazzouz, O.; Martins, V.; Mohamed, K. J.; Pinheiro, L. M.; Rey, D.; Ribeiro, S.; Rubio, B.; Santos, J. F.The sediments of the Galician Interior Basin are influenced by the Atlantic Meridional Overturning Circulation (AMOC) and by their proximity to the Western Iberia continental landmass, and thus provide an adequate archive to study the peculiarities of the last glacial‐interglacial dynamics and the transition into present day conditions. The aim of this study has been to analyse the sedimentary expression of cli...
Geochemical and isotopic studies in the Tabuaço prospect (tungsten mineralizati...
Cerejo, T.; Santos, J. F.; Sousa, J. C.; Castanho, N.; Sérgio, G.; Ribeiro, S.This work took place in the Tabuaço prospect, which corresponds to an area of 45 km2 where exploration for W-skarn deposits is being carried out by Colt Resources. The study now presented results from collaboration among that company, the University of Aveiro, the Geobiotec research unit and the team of the Petrochron project (PTDC/CTE-GIX/112561/2009) and it was focussed on the lithologies recognized, both in...
Geocronologia e geoquímica isotópica de granitoides e metassedimentos da área d...
Cerejo, T.; Santos, J. F.; Sousa, J. C.; Castanho, N.; Sérgio, G.; Ribeiro, S.As litologias identificadas na área da Quinta de São Pedro das Águias correspondem a: xistos biotíticos, xistos negros, mármores, rochas calcossilicatadas s.s. e skarns da sequência metassedimentar da Formação de Bateiras, pertencente ao Grupo do Douro do CXG; granito de Paredes da Beira-Tabuaço; vários corpos aplíticos e pegmatíticos. Para as litologias granitoides, foi obtida uma isócrona Rb-Sr de 311±7 Ma (M...
Geochemistry of granitoids of the Lalezar area (Kerman, Iran)
Niktabar, M.; Moradian, A.; Santos, J. F.; Ahmadipour, H.; Silva, A.The Lalezar granitoids crop out within the Urumiyeh-Dokhtar Volcanic Belt (U-DVB) which is the largest volcanic belt in Central Iran. These granitoids intrude Eocene volcano-sedimentary rocks and range from gabbrodiorites to granites, with dominance of diorites and tonalites. The mineral composition of the most felsic rocks is characterized by the abundance of Na-plagioclase, quartz, alkali feldspar and biotite...
Sr-Nd isotope geology and tectonomagmatic setting of the Dehsalm intrusives (Lu...
Arjmandzadeh, R.; Santos, J. F.; Ribeiro, S.The Dehsalm porphyritic shallow intrusives belong to the Lut Block volcanic-plutonic belt (central eastern Iran). Previous research on alteration, mineralization and hydrothermal fluids indicates that a Cu-Mo porphyry type mineralization system is related with these intrusives (Arjmandzadeh et al., 2012). The rocks studied in this work range in composition from gabbro-diorite to granite, with dominance of monzo...
Sr and Nd isotope data for arc-related (meta) volcanics (SW Iberia)
Santos, J. F.; Mata, J.; Ribeiro, S.; Fernandes, J.; Silva, J.In the southern sector of the Ossa-Morena Zone (Iberian Variscan Chain), along its boundaries with the Beja-Acebuches Ophiolite and the South-Portuguese Zone, Upper Palaeozoic igneous mafic and intermediate rocks, both intrusive and extrusive, are widely represented. The so-called Odivelas Unit (Andrade,1983), include (meta-) basalts and (meta-) andesites, which, according with previous studies, display low-K ...
New U-Pb ages for syn-orogenic magmatism in the SW sector of the Ossa Morena Zo...
Moita, P.; Santos, J. F.; Costa, M. M.; Corfu, F.The Ossa-Morena Zone (OMZ) is a major geotectonic unit within the Iberian Massif (which constitutes an important segment of the European Variscan Belt) and one of its distinguishing features is the presence of a noteworthy compositional diversity of plutonic rocks. In the SW sector of the OMZ, the tonalitic Hospitais intrusion (located to the W of Montemor-o-Novo) is considered a typical example of syn-orogenic...
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