Percorrer por autor "Gumiel, J.C."
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- Exploración regional con analizadores portátiles de fluorescencia de rayos X (FRXp) de la región de Giraúl (Namibe, SW Angola) [Resumo]Publication . Martín-Méndez, I.; Merino-Martínez, E.; Batista, Maria Joao; Feria, María Carmen; Prazeres, Cátia; Gumiel, J.C.; Iglesias-Martinez, M.; Fernández, J.; Chinchilla-Benavides, D.; Gutiérrez-Medina, M.; Buzzi-Marcos, J.; Manuel, JoséRESUMEN: Durante el Proyecto PLANAGEO se llevó a cabo una importante campaña de exploración geoquímica en la región de Giraúl. Los trabajos geoquímicos regionales han consistido en el análisis in situ de muestras de rocas, suelos y sedimentos de corriente mediante analizadores portátiles de fluorescencia de rayos X (FRXp), centrándose en la zona del Campo Pegmatítico de Giraúl, uno de los campos pegmatíticos más extensos del mundo, y también en zonas cercanas con posible interés en minerales críticos. Estos trabajos han permitido definir tres zonas de especial interés: a) el Campo Pegmatítico de Giraúl, donde se han registrado importantes concentraciones de Nb-Ta y donde se están realizando campañas de exploración de Li-Be; b) las formaciones máficas de los metasedimentos del Grupo Namibe y otras intrusiones básicas Paleoproterozoicas, que presentan un potencial interés para metales base (Cr-Ni-Co)-Cu; y c) las formaciones volcánicas cretácicas de la Cuenca de Namibe, que presentan potencial interés para Fe-Ti (V) (Martín-Méndez et al. 2022a, b).
- Maps of Industrial Rocks and Minerals of Angola: CARMINA Project. Products obtained and main resultsPublication . Fernández, J.; Lisboa, Jose; Iglesias-Martínez, Mario; Gumiel, J.C.; Feria, María Carmen; Francés, Alain Pascal; Merino-Martinez, Enrique; Manuel, José; Garcia-Lobon, Jose LuisABSTRACT: Recognizing the pivotal role of the sector in the socioeconomic development of the nation, the Government of the Republic of Angola has actively endorsed the establishment of a geological-mining cartography. This initiative, employing modern methodologies, is a fundamental tool for strategically planning mineral resource exploitation. The outcomes of this initiative underscore the remarkable diversity of substances and the considerable significance of the studied deposits. In the domain of Industrial Rocks and Minerals, specifically within the CARMINA subprogram, a comprehensive compilation of 30 geological-mining maps has been generated. These maps delineate Areas of Mining Potential, and are accompanied by corresponding reports that encapsulate the research findings and technical-analytical outcomes of the investigated regions. The undertaken efforts have unveiled the substantial potential for Natural Stone, featuring novel varieties of granites, marbles, and “exotic” rocks such as amazonites, sodalites, pegmatites, and carbonatites. The last refered rock types are particulary interesting since they serve as sources for industrial rocks and minerals, encompassing valuable resources like lithium and Rare Earths. Thus, these resources exhibit promising prospects in the context of the energy transition. Additionally, noteworthy deposits include high-purity quartz in Equimina region, feldspars in Giraúl area, kaolins and clays within the Cunene Anorthositic Complex. The systematic creation of mineral resource maps, along with the associated research, contributes to the provision of up-to-date information regarding the geological-mining potential of the studied territory.
- Pre-Mesoproterozoic crustal architecture and implications for the Mesoproterozoic evolution of the SW Angolan Shield from structural, geochemical, and isotopic evidence [Resumo]Publication . 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; Manuel, José; Tassinari, Colombo C. G.; Montero, P.; Sato, Kei; Fuenlabrada, José Manuel; Galindo, CarmenABSTRACT: Several studies suggest the existence of multiple tectonic domains within the Angolan Shield [1], yet the Archaean to Palaeoproterozoic basement of SW Angola and NW Namibia remains largely unexplored. Similarly, distinct Mesoproterozoic (1534–1065 Ma) igneous suites are documented in the SW Angolan Shield, including the largest known gabbro-anorthosite complex (~42,500 km²), the Kunene Complex (KC), but the geological evolution of the region during the Mesoproterozoic is still debated. Traditionally linked to anorogenic contexts [2], recent studies propose a collisional setting for the KC [3]. A combined isotopic (U-Pb, Sr-Nd), gravimetric, and structural approach allows for a refined crustal framework of the SW Angolan Shield and provides new insights into the emplacement of the KC and the regional evolution of the southern Congo Craton. This integrated dataset delineates several Archaean to Palaeoproterozoic domains surrounding the KC, featured by a specific gravimetric response and geochronological time span: Cassinga Zone (2667–2568 Ma and 1982–1971 Ma), Central Eburnean Zone (2038–1947 Ma; intruded by 1844–1744 Ma magmatism in its southern region, the Lubango Area), Namibe and Epupa Zones (1861–1739 Ma), and the Kalahari Area (~1775 Ma?). These contrasting crustal domains significantly influenced the genesis and emplacement of the KC.
- 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.
- Remote sensing applied to litho-structural and regolith mapping of the SW of Angola (PLANAGEO Project)Publication . Gumiel, J.C.; López-Bahut, T.; Martín-Banda, Raquel; Quental, LídiaABSTRACT: IGEO (Geological Institute of Angola) has developed the sosubprograms was focused on the remote sensing survey of the country. The main objective of the study is the use of satellite Earth Observation data in order to support preliminary geological and regolith mapping. This allows us to obtain a first approximation to cartography 1:250.000. Litho-structural and regolith maps are elaborated over eight blocks, covering one-third of the country area and including different geological contexts.
- Serie cartográfica de Rocas y Minerales Industriales de Angola: Resultados del proyecto CARMINAPublication . Fernández, J.; Lisboa, Jose; Iglesias-Martínez, M.; Gumiel, J.C.; Feria, María Carmen; Francés, Alain Pascal; Merino-Martínez, E.; Manuel, José; García-Lobón, J. L.RESUMEN: El Gobierno de la República de Angola, consciente de la importancia del sector de las rocas y minerales industriales en el desarrollo socioeconómico de su territorio, evitando la dependencia de la minería metálica, energética y diamantífera, ha promovido la realización una nueva serie cartográfica en el ámbito del subprograma CARMINA, dentro del Proyecto PLANAGEO (Plan Nacional de Geología) para elaborar un total de 30 mapas geológico-mineros. Con una metodología moderna, y definiendo Áreas de Potencialidad Minera, esta serie cartográfica incluye unas memorias asociadas que recogen las investigaciones y resultados técnico-analíticos del área de estudio. Los trabajos han puesto de manifiesto el formidable potencial en el ámbito de las rocas y minerales industriales, recogido en esta nueva serie cartográfica que pretende profundizar en la situación actual del sector, realizando un exhaustivo repaso por todas las rocas y minerales explotadas en la actualidad o en el pasado, la tipología de los yacimientos donde se localizan dichas sustancias, una descripción de cómo se realiza la minería actual de los materiales, los usos principales a los que se destinan, etc., que permita mejorar el conocimiento y aprovechamiento minero de los mismos y tenga aplicación en la ordenación territorial.