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- New insights on the ultramafic intrusions surrounding the Kunene Anorthosite Complex (SW Angola) from gravity, magnetic and radiometric data [Abstract]Publication . Represas, Patricia; Sousa, Pedro; Morais, Igor; Cordeiro, Domingos; Carvalho, João; Batista, Maria Joao; Dito, Manuel; Llorente, J.; Marques, Fábio; Mateus, T.; Rodrigues, José Feliciano; Lobón, Jose Luis Garcia; de Oliveira, Daniel Pipa SoaresABSTRACT: The Kunene Anorthosite Complex (KAC), located in SW Angola, is one of the largest anorthosite structures in the world. Dating from the Mesoproterozoic, its installation process is still not clear. Several mafic and ultramafic outcrops can be found surrounding the KAC. Once considered related with its emplacement, the study of these bodies may help us understand the history of this unique geological feature. While geochronological data show that they are synchronous, or possibly a bit younger, than the embedding granites and migmatites of Paleoproterozoic age, the question arises of whether they are intrusions installed in the host rock or if they are instead recycled remains of older Arch crust. The development of these outcrops in depth provides relevant clues regarding the origin of these bodies and their relationship with the Eburnean (~1.93-2.04 Ga) and Epupa-Namibe (~1.83-1.74 Ga) events. One of these mafic outcrops, designated the Hamutenha outcrop (Huíla Province) exhibits an elongated shape and a NW-SE orientation and is characterized by an internal zonation. Generally, the innermost part is composed of ultramafic rocks of (mostly harzburgites and dunites), with diorites outcropping in its NW and SE borders. The Hamutenha outcrop was previously identified for potentially bearing Cr, Ni and PGE mineralization.
- Late Cretaceous post-rift magma emplacement offshore the West Iberian Margin [Abstract]Publication . Pereira, Ricardo; Escada, Cláudia; Represas, Patricia; Ramalho, R.S.; Mata, João; Rosas, Filipe M.ABSTRACT: The West Iberian Margin is a prime example of a magma-poor hyperextended continental margin. However, the margin is punctuated by three discrete Mesozoic magmatic events, from which the last, occurring 20-40 M.a. after complete lithospheric breakup of the Iberia-Newfoundland conjugate margin, is related to the late Cretaceous Atlantic Alkaline Province. It is characterised onshore by multiple outcropping intrusive (Sintra, Sines and Monchique) and extrusive (e.g., the Lisbon Volcanic Complex) alkaline suites of magmatism, and offshore by conspicuous and enigmatic magnetic anomalies, suggesting additional magmatic features.
- 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.
- Late Cretaceous magmatism offshore the central West Iberian MarginPublication . Pereira, Ricardo; Escada, Cláudia; Represas, Patricia; Mata, João; Rosas, Filipe M.; Ramalho, R.S.SUMÁRIO: A análise de dados de reflexão sísmica, combinados com modelos de inversão de dados potenciais (gravimetria-magnética), revela a presença, natureza e detalhes de um sistema magmático localizado no offshore da Margem Oeste Ibérica. As evidências incluem o vulcão de Fontanelas com escoadas de lavas associadas, a Intrusão do Esporão da Estremadura, e diversos complexos de soleiras, enquanto manifestações da Província Alcalina Atlântica, do Cretácico superior. Este sistema magmático sugere implicações nos modelos de ascensão adiabática no manto, tentativamente associados a uma pluma mantélica duradoura e enraizada na anomalia centro-este atlântica.
- Near-surface wave velocity structure of Faial (Azores - Portugal) Island for site effect studiesPublication . Borges, José Fernando; Neves, Samuel; Caldeira, Bento; Bezzeghoud, Mourad; Carvalho, João; Carvalho, Alexandra
- Unraveling the Paleozoic "Basement" structure and its impact on the petroleum system in the Western Gulf of Cadiz (Southwest Iberia)Publication . Matias, Hugo; Carvalho, João; Menezes, Paulo; Matias, Luís; Santos, Fernando Monteiro; Barbosa, Valéria C. F.
- Velocity and structural model of Lower Tagus Basin (Portugal) derived from ambient seismic noise measurementsPublication . Borges, José Fernando; Torres, Ricardo Jorge Gomes; Silva, Hugo Gonçalves; Caldeira, Bento; Bezzeghoud, Mourad; Carvalho, João; Furtado, Augusto
- Vs30 estimation using ambient vibrations and seismic refraction experiments - Application to the lower Tagus Valley (Portugal)Publication . Costa, Paula Teves; Rodrigues, I.; Torres, Ricardo Jorge Gomes; Carvalho, João; Almeida, I. M.; Borges, José Fernando
- Velocity and structural model of the Lower Tagus Basin according to the study of environmental seismic noisePublication . Torres, Ricardo Jorge Gomes; Furtado, José Augusto; Silva, Hugo Gonçalves; Borges, José Fernando; Caldeira, Bento; Bezzeghoud, Mourad; Carvalho, João
- Massive sulfide exploration models of the Iberian Pyrite Belt Neves Corvo mine region, based in a 3D geological, geophysical and geochemical ProMine studyPublication . Inverno, Carlos; Matos, João Xavier; Rosa, Carlos J. P.; Castelo-Branco, José Mário; Granado, Isabel; Carvalho, João; Batista, Maria Joao; Represas, Patricia; Pereira, Zélia; Oliveira, José Tomás; Araújo, Vítor