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- A Plataforma Portuguesa de geotermia superficial - análise SWOTPublication . Marrero Diaz, Rayco; Madureira, Pedro; Ramalho, Elsa
- Carta geoambiental da região da Grande BeiraPublication . Oliveira, José Tomás; Milisse, Dino; Daudi, Elias Félix; Ramalho, Elsa; Fernandes, Judite; Quental, Lídia; Batista, Maria Joao; Dias, Ruben Pereira; Ussene, Ussene Vasco; Magaia, Almiro; Muchanga, André; Muchibane, Aníbal; Zeferino, Cátia Lídia; Balate, Gabriel; Gomane, Gertrudes; Cune, Grácio; Rebêlo, Luís Pina; Nave, Silvia; Manhiça, Vladimiro; Pereira, Aurete
- Characterization of an Intraplate Seismogenic Zone Using Geophysical and Borehole Data: The Vila Franca de Xira Fault, PortugalPublication . Carvalho, João; Alves, Daniela; Cabral, João; Ghose, Ranajit; Borges, José Fernando; Dias, Ruben Pereira; Ramalho, Elsa; Caldeira, Bento; Casacão, J.; Leote, JaimeABSTRACT: The Vila Franca de Xira (VFX) fault is a regional fault zone located about 25 km northeast of Lisbon, affecting Neogene sediments. Recent shear-wave seismic studies show that this complex fault zone is buried beneath Holocene sediments and is deforming the alluvial cover, in agreement with a previous work that proposes the fault as the source of the 1531 Lower Tagus Valley earthquake. In this work, we corroborate these results using S-wave, P-wave, geoelectric, ground-penetrating radar and borehole data, confirming that the sediments deformed by several fault branches are of Upper Pleistocene to Holocene. Accumulated fault vertical offsets of about 3 m are estimated from the integrated interpretation of geophysical and borehole data, including 2D elastic seismic modeling, with an estimated resolution of about 0.5 m. The deformations affecting the Tagus alluvial sediments probably resulted from surface or near-surface rupture of the VFX fault during M similar to 7 earthquakes, reinforcing the fault as the seismogenic source of regional historical events, as in 1531, and highlighting the need for preparedness for the next event.
- Geofísica aplicada à gestão da água subterrânea e ao ordenamento do território da cidade da BeiraPublication . Daudi, Elias Félix; Ramalho, Elsa; Fernandes, Judite; Batista, Maria Joao; Quental, Lídia; Dias, Ruben Pereira; Milisse, Dino; Ussene, Ussene Vasco; Oliveira, José Tomás; Cune, Grácio; Balate, Gabriel; Manhiça, Vítor
- Testing the use of FDEM EM34 for disseminated chromite prospecting in Trás-os-Montes, PortugalPublication . Ramalho, Elsa; de Oliveira, Daniel Pipa Soares; Santana, Helena
- Contribuição do método geofísico eletromagnético no domínio de tempo para o estudo dos sistemas aquíferos multicamada transfronteiriços da bacia do Kalahari, Cunene, AngolaPublication . Francés, Alain Pascal; Ramalho, Elsa; Santos, Fernando Monteiro; Llorente, J.; Mateus, T.; Cuervo, I.; Lobón, Jose Luis Garcia; Dala, V.; Ditutala, M.; Victorino, Américo da MataSUMMARY: Under the scope of project PLANAGEO, a geophysical survey using the time domain electromagnetic (TDEM) method was planned and conducted. This survey aimed to contribute to the hydrogeological conceptual model of the KOS and KOH aquifer systems, to validate the 1960 data electrical resistivity reprocessing and to define the future location of deep boreholes. The TDEM survey allowed identifying different layers with different geoelectric characteristics and assigning electrical resistivity characteristics to each hydrogeological feature of the aquifer systems. These assumptions were found adequate, and the results were used to define the drilling locations of 5 wells.
- Avaliação do potencial geotérmico do Aquífero Cretácico Inferior na Região de LisboaPublication . Marrero Diaz, Rayco; Ramalho, Elsa; Costa, Augusto Marques da; Ribeiro, Maria Luísa; Carvalho, João; Pinto, Carlos C.; Rosa, Diogo; Correia, Antonio
- Enhancing Resilience of Hot Spring Ecosystems Towards a Model of Sustainable Management of SPA Territories, Driving Innovation and Energy transition [Poster]Publication . Bertin, C.; Iasio, C.; Herms, Ignasi; Arnó, Georgina; Carvalho, João; Ramalho, Elsa; Becerra, S.; Roussel, M.; Brut, E.ABSTRACT: The climate observation systems have classified 2020, 2022, 2019, 2015, and 2014 as the five hottest years in Europe over the past four decades. In the SUDOE region, 2022 was the warmest year since 1950. The projected long-term decline in precipitation in the SUDOE region may alter the natural properties of thermal springs, by changes in of shallow and deep groundwater mixing, impacting their anthropogenic ecosystem. Currently, there is no data assessing the impact of climate change, nor is there any adaptation strategy in place to anticipate its socio-economic consequences. Data on groundwater quality, climate change vulnerability, and territorial adaptive capacity are heterogeneous, exacerbating the economic divide. Migration movements and indirect impacts of climate change, as such as pandemic crises, may further intensify stress on water resources and the economy.
- As águas de Alfama : a riqueza esquecida da cidade de LisboaPublication . Ramalho, Elsa; Lourenço, Maria CarlaA existência de várias nascentes em Alfama, relatada desde pelo menos os tempos árabes, conheceu vários tipos de utilização ao longo dos séculos, fazendo parte da história da cidade de Lisboa. Esta importância histórica revela-se nos vários aspectos relativos à utilização diversificada das águas, como o abastecimento dos barcos durante a época dos descobrimentos, ou ainda através da dinâmica própria que imprimiam à zona, traduzida pela utilização das águas pelas lavadeiras da cidade. Algumas destas nascentes tinham temperatura de emergência superior a 20ºC e, de acordo com relatos de época, eram possuidoras de virtudes terapêuticas que as fizeram, além disso, ser amplamente procuradas e utilizadas pela população de Lisboa, fundamentalmente de parcos recursos. As águas destas nascentes, entretanto totalmente seladas e abandonadas há mais de 25 anos, chegaram a ser qualificadas de "minero-medicinais" pela então Inspecção de Águas, tendo sido assim aproveitadas em vários "balneários públicos" nos finais do século XIX. Estes "balneários públicos" serviram durante décadas a população de Lisboa e arredores, tendo igualmente sido significativamente influentes na vida da cidade. O aparecimento da Fonte das Ratas, na década de 60 do século XX, contribuiu para manter viva actualmente a memória das águas de Alfama. Este trabalho aborda, de uma forma simplificada, a localização geográfica das nascentes baseada na documentação histórica, bem como as características geológicas e hidrogeológicas da zona e o modo como estas águas foram exploradas durante vários séculos. São igualmente feitas algumas considerações respeitantes a possíveis usos que estas águas poderão ter, a verificar-se manterem na actualidade as características que as tornaram famosas.
- Geophysical surveys in the Portuguese sector of the Iberian Pyrite Belt: a global overview focused on the massive sulphide exploration and geologic interpretationPublication . Matos, João Xavier; Carvalho, João; Represas, Patricia; Batista, Maria Joao; Sousa, P.; Ramalho, Elsa; Marques, Fábio; Morais, Igor; Albardeiro, Luís; Gonçalves, Pedro; Dias, P.ABSTRACT: The application of geophysical techniques to massive sulphide deposits exploration has proven to be a success in the Iberian Pyrite Belt (IPB) metallogenetic province, both in Portugal and in Spain. Several hidden deposits were discovered through the interpretation of geological models, supported by geophysical data collected in land and airborne surveys, as well as applied using down hole techniques in selected drill holes. This paper presents an overview of the methodologies applied in Portugal in the South Portuguese Zone (SPZ) geological domain, where the IPB is included, mostly by the LNEG and mining companies, with emphasis on the interpretation of the regional gravity, magnetometry and radiometry surveys, published in 1/400 000 scale by the EXPLORA/Alentejo2020 Project. In this regional mapping program, the large volume of data collected by LNEG and mining companies since the 1960’s was compiled and processed. The integrated interpretation and correlation between these methods will enable a better planning of new IPB exploration investments. IPB Volcano-Sedimentary Complex (VSC, Famennian to Late Visean age) lineaments are well defined in the gravity and magnetic fields along the IPB western region (e.g. Alcoutim/Neves-Corvo/Montinho/Sesmarias/Lousal/Caveira). Aeromagnetic data also reflect deep and large anomalies related with the SPZ basement. A rock density database is presented and used to interpret the gravity data. Radiometric map (Natural Radioactivity), based mostly in airborne radiometric surveys, show contrasts between rocks in Paleozoic, Mesozoic and Cenozoic formations and correlations with geological and hydrothermal mapping are highlighted. The use of geophysical techniques is particularly critical in areas where VSC is concealed by younger sediments (e.g. Baixo Alentejo Flysch Group and/or Cenozoic formations), allowing the selection of target areas. Case studies are discussed based on electromagnetic, seismic and magnetotelluric methods and on the high mineral potential of defined targets. Multilayered data correlation (geophysics including petrophysical data, geochemistry and stratigraphic high-resolution models) is a key prospecting methodology and is essential for the accurate modelling of ore horizons and geological structures. Considering the IPB potential for VMS deposits, including the possible discovery of new giant (> 200 Mt) deposits, an increase of investment in new geophysical methods can be predicted. LNEG development of R&D projects such as EXPLORA/Alentejo2020 and SmartExplorationTM/H2020 also contribute to a favourable setting in the province, both in near mining and green fields scenarios. Thus, new discoveries are expected, like others made in the recent times in the IPB Portuguese sector, such as Lagoa Salgada (SFM, 1992, SFM; Redcorp/EDM, 2011; Redcorp/Ascendant/EDM, 2017), Semblana (Somincor-AGC-Lundin Mining, 2010), Monte Branco (Somincor-Lundin Mining, 2012) and Sesmarias (Maepa/Avrupa, 2014). The importance of these data goes beyond the mineral exploration purpose. Since some of them use rock and mineral physical properties that can be related with environmental contamination (e.g. radiometry and magnetics) they can also be used in geochemical background studies, acid mine drainage and metal dispersion. Therefore, they can also promote a deeper knowledge in other areas of research related with environment preservation.