Percorrer por autor "Ferreira, Ezequiel"
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- Cartografía Geológica del Plan Nacional de Geología de Angola (PLANAGEO)Publication . Merino-Martínez, E.; Rodrigues, José Feliciano; Martín-Banda, Raquel; Francés, Alain Pascal; Feria, María Carmen; López-Bahut, T.; Ferreira, Ezequiel; García-Lobón, J. L.; Gumiel, J. C.; Cuervo, I.; Victorino, Américo da Mata; Manuel, JoséRESUMEN: La cartografía geológica fue la actividad central en la que se basó el Plan Nacional de Geología de Angola (PLANAGEO). Los trabajos de cartografía geológica realizados por el consorcio UTE PLANAGEO (IGME/LNEG/IIA) en el sur de Angola (476.512 km2), desarrollados entre 2016 y 2020, comprendieron 44 cartas a escala 1:250.000, 15 cartas a escala 100.000, 8 mapas de síntesis a escala 1:500.000 y 4 mapas geotemáticos a escala 1:1.000.000. A partir de estos trabajos, fueron distinguidos diversos dominios geológicos en el sur del Escudo de Angola, delimitados por macroestructuras bien definidas en los modelos geofísicos. Los mapas y sus memorias asociadas reúnen todo el conocimiento generado durante PLANAGEO, siendo un manual de referencia geológica y un modelo para futuros estudios geológico-mineros. Los mapas geológicos realizados constituyen la base de una infraestructura regional de conocimiento geológico de la región sur de Angola, y proporcionan información básica para el aprovechamiento óptimo del territorio y desarrollar el potencial de los recursos naturales del país.
- Pre-Mesoproterozoic crustal framework and Mesoproterozoic evolution of the SW Angolan Shield: structural, geochemical, and isotopic insights from the Kunene Complex and surrounding basementPublication . Merino-Martínez, E.; Ferreira, Ezequiel; Valverde-Vaquero, Pablo; Rodrigues, José Feliciano; Escuder-Viruete, Javier; Garcia-Lobon, Jose Luis; Beranoaguirre, Aratz; Feria, María Carmen; Rey-Moral, Carmen; Silva, Paulo Bravo; González-Cuadra, Pablo; Sousa, João Carlo; Potti, Julián; Máximo, J.; Gutiérrez-Medina, M.; Gumiel, J.C.; Galán, Gustavo; Mochales, Tania; Manuel, José; Cordeiro, Domingos; Tassinari, Colombo C. G.; Montero, P.; Sato, Kei; Fuenlabrada, José Manuel; Galindo, CarmenABSTRACT: The southwestern Angolan Shield hosts the Earth's largest Mesoproterozoic massif-type anorthosite complex (up to 53,500 km(2)), the Kunene Complex (KC). This complex is the result of a long-lived (similar to 200 Ma) episodic emplacement of coalescent magmatic pulses. The recent acquisition of multidisciplinary data during the PLANAGEO project has significantly enhanced our understanding of the Precambrian crustal framework from the southwestern Angolan Shield. Combined multi-isotope, structural and geophysical data reveals distinctive crustal zones in the southwestern Angolan Shield that clearly influenced KC's emplacement within a back-arc setting. The spatio-temporal arrangement of KC pulses suggests westwards magma migration within a complex contractional regime involving large strike-slip systems. A long-lasting and extensive accretionary orogen was responsible for the tectono-thermal activity recorded during most of the Mesoproterozoic. Crustal thinning and partial melting of isotopically heterogeneous lower-crustal sources through mantle upwelling promoted the episodic felsic magmatism contemporaneous with the KC. Crustal contamination processes are evident in gabbroanorthosites, indicating mantle metasomatism and interaction with wall-rocks and granite melts during ascent, upwelled by lateral-driven forces. Deposition of extensive metasedimentary sequences (<1.26 Ga) covering the KC, along with 1.23-1.07 Ga sublithospheric and mantle-derived magmatism, indicate a shift from a compressional to an extensional regime during late-Mesoproterozoic times. Regional correlations with other Mesoproterozoic units in African and Brazilian counterparts suggest a shared geological evolution, despite potential differences in tectonic setting. These findings supports a refined geological model for the Mesoproterozoic evolution of the southwestern part of the Congo Craton.
- The UTE-PLANAGEO Project (National Geology Plan of Angola). Objectives, methods, and resultsPublication . Garcia-Lobon, Jose Luis; Merino-Martinez, Enrique; Fernández, J.; Carvalho, João; Batista, Maria Joao; Escuder, Javier; Lisboa, Jose; Martín-Banda, Raquel; Francés, Alain Pascal; Ramalho, Elsa; Martín-Méndez, I.; Rey-Moral, Carmen; Feria, María Carmen; Mochales, Tania; Ferreira, Ezequiel; Cuervo, I.; Manuel, José; Victorino, Américo da MataABSTRACT: The National Geology Plan of Angola (PLANAGEO) has been one of the most important Angolan infrastructure projects throughout the past twenty years. The objectives of PLANAGEO were: (a) to enhance Angola's geological and mineral resources knowledge; (b) to foster diversification of the national economy; and, (c) to attract foreign investment and promote the country development. The project integrated regional interdisciplinary geological surveys, including geological/aerogeophysical/geochemical mapping, raw materials and mineral resources prospecting, as well as specific studies in target areas. The project was launched by the Angolan government (Presidential Resolution 52/09), and implemented by the Geological Survey of Angola (IGEO), under the oversight of the Angolan Ministry of Mineral Resources, Oil and Gas (MIREMPET). In 2011, UTE consortium, a joint venture of IGME, the National Laboratory of Energy and Geology of Portugal (LNEG) and the Spanish company Impulso Industrial Alternativo (IIA) bid the call for tenders. In 2013 IGEO awarded UTE a contract to undertake PLANAGEO´s activities in the southwestern region of Angola, covering roughly 480.000 km2. From July of 2014 to the end of 2022, the UTE consortium conducted interdisciplinary studies and investigations that resulted in a comprehensive collection of maps and scientific reports and documents, comprising: Airborne geophysical mag/rad mapping. Geological mapping at 1:250.000 scale (and 1:500.000 and 1:1.000.000 synthesis). Geological mapping at 1:100.000 scale in selected areas. Geochemical mapping at 1:250.000 scale. Raw materials and Mineral resources mapping in target areas, at 1:50.000 scale.
- Zircon U-Pb and Lu-Hf isotopes reveal the crustal evolution of the SW Angolan Shield (Congo Craton)Publication . Ferreira, Ezequiel; Lehmann, Jeremie; Rodrigues, José Feliciano; Hayes, Ben; Merino-Martinez, Enrique; Milani, Lorenzo; Bybee, Grant M.; Smith, Trishya M. Owen; García-Lobón, J. L.; Tassinari, Colombo C. G.; Ueckermann, Henriette; Sato, Kei; Silva, Paulo Bravo; Correia, João; Labaredas, José; Duarte, Laurent; Molekwa, Mmasetena Anna; Manuel, José; Victorino, Américo da MataABSTRACT: The crustal evolution of the Angolan Shield (AS) remains poorly constrained. To address this, we analysed U-Pb and Lu-Hf isotopes in detrital and igneous zircons to investigate the age and provenance of extensive sedimentary strata in southwestern Angola and use it as a proxy to gain insight into the Archean to Mesoproterozoic evolution of the region. Mesoproterozoic maximum depositional ages for the Iona (<1323 +/- 13 Ma), Ompupa (<1215 +/- 13 Ma), and Cahama (<1184 +/- 23 Ma) siliciclastics challenge previous correlations with the Paleoproterozoic Chela Group. Provenance analysis reveals that the Mesoproterozoic strata were derived internally from the AS. Our combined dataset indicates that the widespread Eburnean magmatism (-2.05-1.93 Ga) resulted from reworking of Archean crust, possibly in collision orogens. A major increase in the eHf(i) and eNd(i) values at - 1.87-1.73 Ga indicates a change in geodynamics, with magmatism of the Epupa-Namibe Metamorphic Complex (ENMC) generated in an extensional accretionary orogen at the southern margin of the Eburnean-Archean crustal block. Magmatism resumed in the Mesoproterozoic (-1.56-1.50 Ga), with suprachondritic eHf(i) values indicating significant juvenile addition. The Kunene Complex (KC: -1.50-1.36 Ga) anorthosite-mangerite-charnockite-granite magmatism displays variable eHf(i) and eNd(i) values, consistent with mixing between reworked ENMC-crust and juvenile melts in a long-lived accretionary orogen back-arc region. Post-KC (-1.36-1.30 Ga) magmatism shows an increased juvenile contribution, potentially linked to partial melting of ENMC and - 1.56-1.50 Ga juvenile crust during an orogenic event, or alternatively, related to renewed slab retreat and back-arc extension. The Hf isotopic compositions of - 1.29-1.18 Ga zircons are compatible with a renewed input from the depleted mantle and/or reworking of the earlier - 1.56-1.50 Ga juvenile crust. Emplacement of - 1.13-1.10 Ga mafic dikes/sills marks the end of Mesoproterozoic magmatism in the AS. Our new data enhance our understanding of the Archean to Mesoproterozoic crustal evolution of the AS.