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- U-Pb geochronology of felsic volcanic rocks hosted in the Gafo Formation, South Portuguese Zone : the relationship with Iberian Pyrite Belt magmatismPublication . Rosa, Diogo; Finch, A. A.; Andersen, T.; Inverno, Carlos
- Argemela, a high-tonnage Sn-Li deposit in Central Portugal [Abstract]Publication . Inverno, Carlos; Ferraz, Paulo J. V.
- Mineralizações de magnetite e sulfuretos de Monges (Santiago do Escoural, Montemor-o-Novo), Vale de Pães (Cuba-Vidigueira) e Orada (Pedrógão, Serpa) : Síntese de ensaio comparativoPublication . Salgueiro, Rute; Mateus, António; Inverno, CarlosAs mineralizações Monges (Montemor-o-Novo), Vale de Pães (Cuba-Vidigueira) e Orada (Serpa), incluídas na Faixa Magnetítico-Zincífera da Zona de Ossa-Morena (ZOM), evidenciam características mineralógicas e geoquímicas diferentes, não obstante partilharem uma constituição dominada por magnetite ± sulfuretos (pirite, pirrotite e calcopirite). A diferença é tanto mais notória quando se compara Monges (possivelmente um sistema misto do tipo SEDEX-VMS) com Vale de Pães ou Orada, as duas últimas representando sistemas do tipo Skarn-Fe(Mg/Ca). Os dados disponíveis permitem ainda posicionar o desenvolvimento destes sistemas mineralizantes em contextos geológicos distintos, correlacionáveis com diferentes estádios da evolução geodinâmica/metalogenética da ZOM.
- New data on nodular monazite from Monfortinho (Idanha-a-Nova, Portugal)Publication . Salgueiro, Rute; Inverno, Carlos; De Oliveira, Daniel Pipa Soares; Guimarães, Fernanda
- Mineralogy and metasomatic evolution of distal strata-bound scheelite skarns in the Riba de Alva Mine, Northeastern PortugalPublication . Gaspar, L. Miguel; Inverno, Carlos
- Levelling geochemical datasets as a tool to overcome boundary features in data applied to mineral explorationPublication . Batista, Maria Joao; de Oliveira, Daniel Pipa Soares; Salgueiro, Rute; Inverno, CarlosABSTRACT: The existence of a large number of chemical analyses resulting from decades of geochemical exploration campaigns, yields huge numbers of analytical results produced with different analytical methods, sampling protocols and sampling means. Therefore, it is necessary to level these analytical results to make them comparable and thus take advantage of the potential of geochemical information from contiguous areas. In this study, a levelling technique was used on geochemical datasets of tested bands between the 1:25 000 scale maps, 293/294 and 305/306 sheets, respectively, from the Beira Baixa region where stream sediments were sampled during a project for rare earth elements exploration. These samples were analysed for lanthanum by the same analytical methods and in the same laboratory, but in different periods and the border effects were observed. These levelling techniques must be adapted to the data to be compared and in the present case the disappearance of the border effect of the analytical results of 293/294 and 305/306 topographic sheets was observed.
- Chemical composition of submarine massive sulphides in the Lucky Strike hydrothermal fieldPublication . Ferreira, Pedro Tavares; Inverno, Carlos; Silva, Teresa; Schiellerup, Henrik; González, JavierSUMÁRIO: No segmento Lucky Strike, localizado na Crista Média da região dos Açores, existe um dos maiores campos submarinos hidrotermais activos do nosso planeta. Para além da existência de dezenas de chaminés hidrotermais expelindo fluidos a elevadas temperaturas (~325 ºC), uma área significativa com cerca de 1 km2 é constituída por um substrato rochoso formado por placas hidrotermais e sulfuretos maciços polimetálicos. Durante a campanha oceanográfica TTR-10, oito locais desta área foram amostrados resultando um conjunto de rochas que foram incluídos em três grupos: 1) fragmentos de chaminés hidrotermais, com a estrutura original preservada; 2) fragmentos irregulares de sulfuretos maciços sem estruturação (“sulphide rubble”); 3) Fragmentos de rochas basálticas com variáveis graus de alteração hidrotermal. Neste trabalho apresentam-se as principais características químicas (elementos maiores e traço) e mineralógicas destes três tipos de rochas.
- Modelling of the Neves Corvo AreaPublication . Inverno, Carlos; Rosa, C.; Matos, João Xavier; Carvalho, João; Castelo-Branco, José Mário; Batista, Maria Joao; Granado, Isabel; Oliveira, José Tomás; Araújo, Vítor; Pereira, Zélia; Represas, Patricia; Solá, A. Rita; Sousa, Pedro
- Alluvial xenotime and heavy minerals assemblage from the northern edge of Nisa-Albuquerque Batholith, eastern Portugal : provenance and geochemical implicationsPublication . Salgueiro, Rute; Rosa, Diogo; Inverno, Carlos; de Oliveira, Daniel Pipa Soares; Solá, A. Rita; Guimarães, FernandaAlluvial xenotime and heavy minerals assemblage from the northern edge of Nisa-Albuquerque Batholith, eastern Portugal : provenance and geochemical implications / Rute Salgueiro... [et al.]. - Amsterdam : Elsevier, 2014. - [18] p. : il., 13 figuras e 8 tabelas ; 30 cm The xenotime-bearing heavy mineral assemblages present in the alluvial samples from Vila Velha de Ródão, Nisa, Póvoa e Meadas and Sto. António das Areias, localized in the northern edge of Nisa-Albuquerque Batholith, Eastern Portugal, were studied in detail. The insights for mineral provenance came from the analysis of the drainage network and from the composition of the regional alluvial samples and outcropping lithologies. Since xenotime is a mineral with economic interest, the motivation of the current work is its contribution for exploration studies, considering the potential information contained in the alluvial samples. In the study region, the alluvial heavy minerals and their morphology reflect clearly the mineralogy and relative distance to their source, respectively. In alluvial samples with direct provenance from the Nisa granite (late Carboniferous), the increase in xenotime concentration and decrease in monazite, apatite, zircon, ilmenite and iron oxide concentration, from W (Nisa) to E (Sto. António das Areias), matches the increase in P2O5 and decrease in REE, CaO, Zr, TiO2, and Fe2O3 contents in granite rocks. The geochemical signature of xenotime studied reveals an igneous source, characterized by the characteristic strong Eu negative anomaly in REE patterns. Their YPO4 values (72–78 mol%) are similar to xenotime from Erzgebirge (Germany) granites. The high values of Y/Ho (50–71) and, in some cases, downward kinks at Ho in REE plots, suggest generation in late stages of crystallization and association with a siliceous evolved magmatic system. The slight decrease in HREE contents in xenotime, from W to E, and Ho anomalies in the normalized REE pattern are similar to those identified in the Nisa granite, which supports the sourcing of xenotime from these granitic rocks. The genetic development of the batholith chemical zonation (more evolved to E) seems to have favoured the generation of xenotime instead of apatite, monazite and zircon, in the eastern end area (Sto. António das Areias). Supporting the geochemical signature, the alluvial zircons also display morphological typologies that are compatible with provenance from peraluminous granites formed at temperatures of 600–700 °C, possibly from the Nisa granite. Since all xenotime grains show the same magmatic affinity, this leads to the hypothesis that the xenotime from the Vila Velha de Ródão sample, with provenance from Cenozoic sedimentary rocks, has been transported to this northern area, after been disaggregated from Nisa batholith granites, most probably by braided anastomosing and erratically sandy channels, that explains its actual position in the opposite bank of the Tagus river. This phosphate has been deposited with other sediments in tectonic depressions and subsequently included in the formation of sedimentary rocks. The greater development of Ca, Th and U phosphate inclusions/substitutions in these xenotime grains can be explained by the chemical mobility provided during all the geological processes.
- Introduction and geological setting of the Iberian Pyrite BeltPublication . Inverno, Carlos; Díez-Montes, Alejandro; Rosa, C.; García-Crespo, J.; Matos, João Xavier; García-Lobón, J. L.; Carvalho, João; Bellido Mulas, Félix; Castelo-Branco, José Mário; Ayala, C.; Batista, Maria Joao; Rubio, F.; Granado, Isabel; Tornos, F.; Oliveira, José Tomás; Rey, C.; Araújo, Vítor; Sánchez-García, Teresa; Pereira, Zélia; Represas, Patricia; Solá, A. Rita; Sousa, Pedro
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