Browsing by Author "Cunha, Pedro Proença e"
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- Assessment of metal and metalloid contamination in soils trough compositional data: the old Mortórios uranium mine area, central PortugalPublication . Neiva, A.M.R.; Albuquerque, M.T.D.; Antunes, I. Margarida H. Ribeiro; Carvalho, P.C.S.; Santos, A. C. T.; Boente, C.; Cunha, Pedro Proença e; Henriques, S.B.A.; Pato, R. L.ABSTRACT: Soils from the old Mortórios uranium mine area were studied to look for contamination, as they are close to two villages, up to 3 km away, and used for agriculture. They are mainly contaminated in U and As and constitute an ecological threat. This study attempts to outline the degree to which soils have been affected by the old mining activities through the computation of significant hot clusters, Traditional geostatistical approaches commonly use raw data (concentrations) accepting that the analyzed elements represent the soil’s entirety. However, in geochemical studies these elements are just a fraction of the total soil composition. Thus, considering compositional data is pivotal. The spatial characterization, considering raw and compositional data together, allowed a broad discussion about not only the concentrations’ spatial distribution, but also a better understanding on the possibility of trends of “relative enrichment” and, furthermore an insight in U and As fate. The highest proportions (compositional data) on U (up to 33%), As (up to 35%) and Th (up to 13%) are reached in the south-southeast segment. However, the highest concentrations (raw data) occur in north and northwest of the studied area, pointing out to a “relative enrichment” toward the south-southeast zone. The Mondego Sul area is mainly contaminated in U and As, but also in Co, Cu, Pb and Sb. The Mortórios area is less contaminated than the Mondego Sul area.
- Assessment of metal and metalloid contamination in the waters and stream sediments around the abandoned uranium mine area from Mortórios, central PortugalPublication . Neiva, A.M.R.; Carvalho, P.C.S.; Antunes, I. Margarida H. Ribeiro; Albuquerque, M.T.D.; Santos, A.C.S.; Cunha, Pedro Proença e; Henriques, S.B.A.ABSTRACT: In the abandoned Mortórios uranium mine area there are quartz veins containing wolframite and sulphides and basic rock dykes with torbernite and autunite cutting a porphyritic granite. The basic rock dykes were exploited and produced about 27 t of U3O8, from 1982 to 1988. There are an open pit lake and nine dumps. Surface water and groundwater are contaminated in U, As, Cd, Cr, Cu, Fe, Mn, Ni and Pb. Stream sediments are contaminated in U, As, Th and W, which are adsorbed by smectite, kaolinite and iron- and aluminium- oxy-hydroxides. The maximum U concentrations are of 1268 μg/L in the open pit lake, 100 μg/L in surface water, 103 μg/L in groundwater and 81.5 mg/kg in stream sediments all downstream of the open pit lake and dumps. Further downstream the U concentration in water decreases, due to the high mobility of U (VI), but the U concentration in stream sediments increases. Calcium uranyl carbonate dominates in the open pit lake, but uranyl carbonate complexes dominate in surface water and gr oundwater. The maximum As concentrations are 56.0 μg/L in the open pit lake, 63.4 μg/L in the surface water and 66.7 μg/L in the groundwater, both downstream of the open pit lake and dumps. The arsenic occurs as As (V). The Mortórios area is compared with two other areas exploited from open pits, all located in the uranium-bearing Beira area of central Portugal. Vale de Abrutiga produced 90 t of U3O8 between 1982 and 1989 and Mondego Sul produced 75 t of U3O8 from 1987 to 1991. The two mines consist of quartz veins containing sulphides, saleeite and meta-saleeite at Vale de Abrutiga and with sulphides, autunite, torbernite, meta-uranocircite and meta-saleeite at Mondego Sul cutting the Schist-graywacke Complex. The mine area of Vale de Abrutiga with the highest exploitation of U3O8 has strongly acidic to slight alkaline water, which is the most contaminated. Mortórios with the lowest exploitation presents a higher contamination of slightly acidic to alkaline water than that of acidic to alkaline water from Mondego Sul, but the former has As (V), whereas the latter has As (III), which is toxic. The stream sediments from Mortórios present the lowest contamination, except for Th that has a higher median value than that from Vale de Abrutiga. Stream sediments from Mondego Sul have higher U, Th, Pb and lower Co, Cr, Cu and Zn median values than those of Vale de Abrutiga.
- Cenozóico das bacias do Douro (sector ocidental), Mondego, Baixo Tejo e AlvaladePublication . Pais, João; Cunha, Pedro Proença e; Legoinha, Paulo Alexandre; Dias, Ruben Pereira; Pereira, Diamantino Ínsua; Ramos, Ana Baía
- Definition of the Portuguese frameworks with international relevance as an input for the European geological heritage characterisationPublication . Brilha, José Bernardo; Andrade, César; Azerêdo, Ana Cristina; Barriga, Fernando; Cachão, Mário; Couto, Helena; Cunha, Pedro Proença e; Crispim, José António; Dantas, Pedro; Duarte, Luís Victor; Freitas, Maria da Conceição; Granja, Helena Maria; Henriques, Maria Helena; Lopes, L.; Madeira, José; Matos, João Xavier; Noronha, Fernando; Pais, João; Piçarra, José Manuel; Ramalho, Miguel Magalhães; Relvas, Jorge M.R.S.; Ribeiro, António; Santos, A.; Santos, Vanda Faria dos; Terrinha, Pedro
- Incorporating descriptive metadata into seismic source zone models for seismic-hazard assessment : a case study of the Azores-West Iberian RegionPublication . Vilanova, Susana P.; Nemser, Eliza S.; Besana-Ostman, Glenda M.; Bezzeghoud, Mourad; Borges, José Fernando; Silveira, António Brum da; Cabral, João; Carvalho, João; Cunha, Pedro Proença e; Dias, Ruben Pereira; Madeira, José; Lopes, Fernando Carlos; Oliveira, Carlos Sousa; Perea, Hector; García-Mayordomo, Julián; Wong, Ivan G.; Arvidsson, Ronald; Fonseca, João F. B. D.In probabilistic seismic-hazard analysis (PSHA), seismic source zone (SSZ) models are widely used to account for the contribution to the hazard from earthquakes not directly correlated with geological structures. Notwithstanding the impact of SSZ models in PSHA, the theoretical framework underlying SSZ models and the criteria used to delineate the SSZs are seldom explicitly stated and suitably documented. In this paper, we propose a methodological framework to develop and document SSZ models, which includes (1) an assessment of the appropriate scale and degree of stationarity, (2) an assessment of seismicity catalog completeness-related issues, and (3) an evaluation and credibility ranking of physical criteria used to delineate the boundaries of the SSZs. We also emphasize the need for SSZ models to be supported by a comprehensive set of metadata documenting both the unique characteristics of each SSZ and the criteria used to delineate its boundaries. This procedure ensures that the uncertainties in the model can be properly addressed in the PSHA and that the model can be easily updated whenever new data are available. The proposed methodology is illustrated using the SSZ model developed for the Azores–West Iberian region in the context of the Seismic Hazard Harmonization in Europe project (project SHARE) and some of the most relevant SSZs are discussed in detail.
- O inventário nacional do património geológico : abordagem metodológica e resultados = The national inventory of geological heritage : methodological approach and resultsPublication . Brilha, José Bernardo; Alcalá, L.; Almeida, A.; Araújo, Alexandre; Azerêdo, Ana Cristina; Azevedo, Maria do Rosário; Barriga, Fernando; Silveira, A. Brum da; Cabral, João; Cachão, Mário; Caetano, Paulo Sá; Cobus, A.; Coke, Carlos; Couto, H.; Crispim, J.; Cunha, Pedro Proença e; Dias, Ruben Pereira; Duarte, Luís Victor; Dória, Armanda; Falé, Patrícia; Ferreira, Narciso; Soares, A. Ferreira; Fonseca, Paulo E.; Carvalho, A. Galopim de; Gonçalves, R.; Granja, H.; Henriques, Maria Helena; Kullberg, J. C.; Kullberg, Maria Carla; Legoinha, Paulo; Lima, A.; Lima, E.; Lopes, L.; Madeira, J.; Marques, J. F.; Martins, A.; Martins, R.; Monteiro, C.; Moreira, M.; Moura, D.; Carvalho, Carlos Neto; Noronha, Fernando; Nunes, J. C.; Oliveira, José Tomás; Pais, João; Reis, Rui Pena; Pereira, D.; Pereira, P.; Pereira, Zélia; Piçarra, José Manuel; Pimentel, N.; Jesus, A. Pinto de; Prada, S.; Prego, A.; Ramalho, L.; Ramalho, Miguel Magalhães; Ramalho, R.S.; Relvas, Jorge M.R.S.; Ribeiro, António; Ribeiro, M. A.; Rocha, Rogério Bordalo; Sá, Artur Abreu; Santos, V.; Sant'Ovaia, H.; Sequeira, António J. D.; Sousa, M.; Terrinha, Pedro; Valle Aguado, B.; Vaz, NunoA existência de um inventário nacional de património geológico é fundamental para se poderem implementar estratégias de geoconservação. Este trabalho apresenta a metodologia usada no desenvolvimento do mais completo inventário de geossítios. realizado até ao momento em Portugal, assim como os principais resultados obtidos. O inventário vai integrar o Sistema de Informação do Património Natural e o Cadastro Nacional dos Valores Naturais Classificados, ambos geridos pelo Instituto de Conservação da Natureza e da Biodiversidade.
- New seismic source zone model for Portugal and Azores for use in SHARE: methodology and preliminar resultsPublication . Vilanova, Susana; Oliveira, Carlos Sousa; Silveira, A. Brum da; Madeira, J.; Nemser, Eliza; Fonseca, J. F. B. D.; Arvidsson, R.; Besana-Ostman, G. M.; Bezzeghoud, Mourad; Borges, José Fernando; Cabral, João; Carvalho, João P. F.; Cunha, Pedro Proença e; Dias, Ruben Pereira; Lopes, Fernando Carlos; Perea, H.; Wong, I.
- Typological classification of clayey raw materials for ceramics manufacture, in the Tábua region (central Portugal)Publication . Lisboa, Jose; Carvalho, Jorge; Cunha, Pedro Proença e; Oliveira, ÁlvaroMapping of clay resources in the Cenozoic deposits of the Tábua region (central Portugal) has been carried out, together with the chemical, mineralogical and technological characterization of seventeen clay samples. The study was undertaken to relate the lithostratigraphic units and the typology of raw materials with regard to the manufacture of ceramics. The sedimentary succession comprises two units with different suitability for the manufacture of ceramics: an upper unit, with clays that present technological restrictions; and a lower unit with a much greater potential. A small set of parameters has been identified which differentiate the typological units. These parameters allow a realistic estimation to be made of the ceramic properties of any clay layer sampled in the study area. It is anticipated that with minor field work and sampling, the typological column can also be used in adjacent areas.