76 documents found, page 1 of 8
Petrochronology of the metamorphic belt located west of the Porto-Tomar Shear Z...
Bento dos Santos, Telmo; Carvalho, Diogo; Damas, Elton; Webb, Laura; Chichorro, Martim; Moreira, Noel; Romão, JoséThe nature of the metamorphic belt located west of the Porto-Tomar Shear Zone (central-west Portugal) has been abundantly discussed in terms of its pre-Variscan paleogeography (Moreira et al., 2019; Bento dos Santos et al., 2023). However, not enough attention has been given to its metamorphic evolution during the Variscan Orogeny and ensuing deformation/metamorphic stages. In this work, we aim at providing qua...
Estudo geocronológico das unidades metassedimentares do soco Pré-Mesozoico a Oe...
Carvalho, Diogo; Bento dos Santos, Telmo; Chichorro, Martim; Cachapuz, Pedro; Solá, Rita; Dantas, Elton; Romão, José; Moreira, NoelTo the west of the Porto-Tomar Shear Zone, several pre-Mesozoic metasedimentary outcrops belonging to the basement of the Lusitanian Basin are poorly exposed. The traditional view suggests that these units belong to Ossa Morena Zone (OMZ), while more recent models propose the existence of the Finisterra Terrane (TF), considered exotic relative to the Iberian Massif (Moreira et al., 2019). To better constrain th...
The bimodal Fii-A2-type and calc-alkaline volcanic sequence of the Aljustrel br...
Lains Amaral, João; Solá, A. Rita; Santos, Telmo M. Bento Dos; Feitoza, L. M.; Tassinari, Colombo C. G.; Crispim, Lourenço; Chichorro, MartimABSTRACT: The Iberian Pyrite Belt (IPB) is a late Devonian- Early Carboniferous world-class polymetallic VMS province that includes significant Cu-(Sn)-Pb-Zn-(Ag) deposits of massive sulphides and feeder zones. The Aljustrel brownfield region contains one of the highest concentrations of ore in the IPB in 6 known deposits (Gaviao, Sao Joao, Moinho, Algares, Estacao and Feitais). To delve into the petrogenesis o...
Dados geocronológicos para o soco pré-Mesozoico localizado a Oeste da Falha Por...
Santos, Telmo M. Bento Dos; Chichorro, Martim; Carvalho, D.; Cachapuz, P.; Solá, A. Rita; Dantas, E.; Romão, José; Moreira, Noel; Silva, I. Dias daSUMMARY: Geochronological data from the pre-Mesozoic basement of the Lusitanian Basement (West of the Porto-Tomar Fault) was obtained. Results show a predominant Cadomian/Pan-African and Eburnean inheritance/source, placing this sector as a peri-Gondwanan domain. However, two major differences can be seen in the data: samples with a clear absence in Mesoproterozoic ages vs. samples with a clear presence of thes...
Geochronological data for the Pre-Mesozoic basement located west of the Porto-T...
Bento dos Santos, Telmo; Chichorro, Martim; Carvalho, Diogo; Cachapuz, Pedro; Solá, Rita; Dantas, E.; Romão, José; Moreira, Noel; Dias da Silva, ÍcaroGeochronological data from the pre-Mesozoic basement of the Lusitanian Basement (West of the Porto-Tomar Fault) was obtained. Results show a predominant Cadomian/Pan-African and Eburnean inheritance/source, placing this sector as a peri-Gondwanan domain. However, two major differences can be seen in the data: samples with a clear absence in Mesoproterozoic ages vs. samples with a clear presence of these ages an...
Novos dados U-Pb em zircão do Maciço de Évora e correlação com as unidades basa...
Solá, A. Rita; Chichorro, Martim; Cachapuz, P.; Santos, Telmo M. Bento DosSUMMARY: We present new U-Pb zircon data from the Évora Massif (SW Ossa–Morena Zone). Série Negra paragneiss of Escoural Fm. yields a maximum depositional age of ~580 Ma. Felsic orthogneiss “leptinites” included in Escoural Fm., commonly attributed to the Precambrian, yield a concordant age of 513 ± 3 Ma. Felsic volcanics interbedded in the Monfurado Fm. and the Safira Orthogneiss show very discordant zircon ag...
Dados geocronológicos para o soco pré-Mesozoico localizado a Oeste da Falha Por...
Santos, Telmo M. Bento Dos; Chichorro, Martim; Carvalho, D.; Cachapuz, P.; Solá, A. Rita; Dantas, E.; Romão, José; Moreira, Noel; Silva, I. Dias daSUMMARY: Geochronological data from the pre-Mesozoic basement of the Lusitanian Basement (West of the Porto-Tomar Fault) was obtained. Results show a predominant Cadomian/Pan-African and Eburnean inheritance/source, placing this sector as a peri-Gondwanan domain. However, two major differences can be seen in the data: samples with a clear absence in Mesoproterozoic ages vs. samples with a clear presence of thes...
U-Pb detrital zircon ages during tectonic inversion: provenance analysis of sil...
Chichorro, Martim; Santos, Telmo M. Bento Dos; Solá, A. Rita; Lopes, C.; Cachapuz, P.SUMÁRIO: Análise de proveniência de sucessões detríticas da Zona de Ossa-Morena é reinterpretada a fim de demarcar os estádios de inversão tectónica do Ciclo Varisco. Zircões detríticos de unidades de Rift do Câmbrico médio-superior (Fm de Ossa, Fm de Fatuquedo) mostram não ter existido variações significativas das áreas fonte quando comparadas com os sedimentos ediacarianos, que refletem erosão/reciclagem da c...
First evidence of Cadomian felsic magmatism in the Évora-Aracena Domain, Ossa-M...
Cachapuz, P.; Chichorro, Martim; Santos, Telmo M. Bento Dos; Carvalho, D.; Benoit, M.; Dantas, E.; Solá, A. RitaSUMÁRIO: Dados geoquímicos obtidos em meta-riólitos da região de Viana do Alentejo incluídos na formação Xistos de Moura permitem diferenciar 3 grupos distintos: Grupo I – rico em HREE com assinatura orogénica; Grupo II – também enriquecido em HREE, mas apresentando natureza anorogénica; e Grupo III - anorogénico, mais enriquecido em REE que os anteriores. Tais informações, quando combinadas com dados geocronol...
Detrital zircon similarities and dissimilarities between the Iberian Pyrite Bel...
Amaral, Joao Lains; Solá, A. Rita; Santos, Telmo M. Bento Dos; Chichorro, MartimABSTRACT: Despite the so-called exotic nature of the South Portuguese Zone relatively to the other major domains of the Iberian Massif of peri-Gondwanan affinity, Devonian detrital rocks of the oldest strata in the Iberian Pyrite Belt have a remarkable resemblance with the Ossa-Morena Zone’s Neoproterozoic-Cambrian rocks and the West Meguma’s Cambrian-Ordovician rocks, presenting the so-called “West African sig...