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Percorrer por autor "Lopes, R."

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  • 3D Magnetic Inversion in Angola: Serra da Neve Alkaline Complex and Jamba Itabirites case studies
    Publication . Machadinho, Ana; Represas, Patricia; Alves, Daniela; Cordeiro, Domingos; Carvalho, João; Lopes, R.; Caessa, Paulo; Pereira, L. F; Osório, A.
    ABSTRACT: Demanding and speculative economies make it imperative to search for new areas of mineral exploration. Angola’s geological diversity presents an enormous potential for mineral resources. This potential can be assessed by applying different methods, such as geophysical prospecting, to discover new potential targets of areas to explore. For many years, the magnetic method has been successfully used in mineral exploration. In this work we apply a 3D magnetic inversion technique to aeromagnetic data in two different study areas. The Serra da Neve alkaline complex (SNAC) represents a potential source for rare earth elements (REE) and the Jamba itabirites provides metallic mineral deposits with iron and gold mineralizations. In both case studies, whether concerning alkaline intrusions or itabirites deposits, their magnetic properties are characterized by strong magnetic anomalies clearly delineated on magnetic anomaly maps. The high magnetic susceptibility (k) contrast between these target structures and the host rocks allowed us to obtain a coherent three-dimensional geometry for the SNAC structures and the itabirites deposits. The magnetic inversion technique also provided magnetic vector inversion (MVI)susceptibility values estimation for constituent lithologies, as well as the shape and size of the studied structures and deposits. The results demonstrate the effectiveness of the magnetic method for the detection and characterization of target areas, offering an innovative technique to identify potential areas in mineral resources exploration.
    2025-08Artigo de investigação Acesso aberto Ver mais
  • El Complejo Calco-Alcalino de la Serra da Neve (SW Angola): trabajos en curso [Resumo]
    Publication . Prazeres, Cátia; Batista, Maria Joao; Lopes, R.; Barros, B.; Ferreira da Costa, P.; Labaredas, José; Guimarães, Fernanda; Rodrigues, José Feliciano; Cordeiro, Domingos
    RESUMEN: El Complejo Calco-Alcalino de la Serra da Neve (CACSN) constituye un conjunto de estructuras alcalinas volcánicas, subvolcánicas y plutónicas emplazadas en una tendencia general ONO-ESE a NOSE (Pereira y Moreira, 1978; Lopes y Caessa, 2021). Fue remapeado a escala 1:100.000 para la cartografía geológica del proyecto PLANAGEO y posteriormente fue una de las áreas seleccionadas para realizar exploración mineral para ETR-Nb-Ta a escala regional. Las campañas de campo incluyeron levantamientos con FRX portátil y SRG portátil, cuyos resultados mostraron patrones preliminares de distribución de ETR en las litologías del CACSN (Prazeres et al., en revisión). Los muestreos realizados durante el trabajo de campo permitieron estudios petrográficos y análisis con microsonda electrónica, que son la base para comprender la mineralogía de los ETR. Hasta ahora se ha demostrado que algunos carbonatos (bastnasita), fosfatos (apatito y xenotima), minerales de Zr (eudialita) y esfena incorporan cantidades apreciables de ETR, especialmente ETR ligeros.
    2024-07Artigo científico Acesso aberto Ver mais
  • Sustainable Production Programme in Setúbal Region (PROSSET) : preliminary results1
    Publication . Duarte, Ana Paula; Peneda, Maria Constança; Sousa Rocha, Cristina; Saraiva, C.; Catarino, Justina; Frazão, Rui; Marçal, M.; Trindade, Paula; Ventura, Fernando; Clerigo, C.; Fernandes, Rui; Lança, Ana; Lopes, R.; Maia, Anabela; Wijn, R. de
    ABSTRACT: In this paper the PROSSET Programme is described briefly and the preliminary results are presented. The Programme includes cleaner production (CP) demonstration projects developed in 10 companies located in the Setúbal Region and the testing of methodologies to promote the sustainability of the Programme. Both the involvement of local agents and the training and/or awareness of workers and locals were considered necessary. The INETI/ITA team developed an action plan aimed at the effective involvement of local actors in the PROSSET Programme in addition to the in-company activities.
    1999-06Artigo científico Acesso aberto Ver mais