Browsing by Author "Rey-Moral, Carmen"
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- Detailed in-depth mapping of the world largest anorthositic complex: Magnetic anomalies, 2.5-3D modelling and emplacement constraints of the Kunene Complex (KC), SW AngolaPublication . Merino-Martínez, E.; Rey-Moral, Carmen; Machadinho, Ana; Carvalho, João; Represas, Patricia; García-Lobón, J. L.; Feria, María Carmen; Martín-Banda, Raquel; López-Bahut, T.; Alves, Daniela; Ramalho, Elsa; Manuel, José; Cordeiro, DomingosABSTRACT: The Kunene Complex (KC) represents a very large Mesoproterozoic igneous body, mainly composed of anorthosites and gabbroic rocks that extends from SW Angola to NW Namibia (outcropping 18,000 km2 , NE-SW trend, and ca. 350 km long and up to 50 km wide). Little is known about its structure at depth. Here, we use recently acquired aerogeophysical data to accurately determine its hidden extent and to unravel its morphology at depth. These data have been interpreted and modelled to investigate the unexposed KC boundaries, reconstructing the upper crustal structure (between 0 and 15 km depth) overlain by the thin sedimentary cover of the Kalahari Basin. The modelling reveals that the KC was emplaced in the upper crust and extends in depth up to ca. 5 km, showing a lobular geometry and following a large NE-SW to NNE-SSW linear trend, presumably inherited from older Paleoproterozoic structures. The lateral continuation of the KC to the east (between 50 and 125 km) beneath the Kalahari Cenozoic sediments suggests an overall size three times the outcropping dimension (about 53,500 km2 ). This affirmation clearly reinforces the economic potential of this massif, related to the prospecting of raw materials and certain types of economic mineralization (Fe-Ti oxides, metallic sulphides or platinum group minerals). Up to 11 lobes have been isolated with dimensions ranging from 135.5 to 37.3 km in length and 81.9 to 20.7 km in width according to remanent bodies revealed by TMI mapping. A total volume of 65,184 km3 was calculated only for the magnetically remanent bodies of the KC. A long-lasting complex contractional regime, where large strike-slip fault systems were involved, occurred in three kinematic pulses potentially related to a change of velocity or convergence angle acting on previous Paleoproterozoic inherited sutures. The coalescent magmatic pulses can be recognized by means of magnetic anomalies, age of the bodies as well as the lineations inferred in this work: (i) Emplacement of the eastern mafic bodies and granites in a stage of significant lateral extension in a transtensional context between 1500 Ma and 1420 Ma; (ii) Migration of the mantle derived magmas westwards with deformation in a complex contractional setting with shearing structures involving western KC bodies and basement from 1415 Ma to 1340 Ma; (iii) NNW-SSE extensional structures are relocated westwards, involving mantle magmas, negative flower structures and depression that led to the formation of late Mesoproterozoic basins from 1325 Ma to 1170 Ma. Additionally, we detect several first and second order structures to place the structuring of the KC in a craton-scale context in relation to the crustal structures detected in NW Namibia. (c) 2025 China University of Geosciences (Beijing) and Peking University. Published by Elsevier B.V. on behalf of China University of Geosciences (Beijing).
- El Plan Nacional de Geología de Angola (PLANAGEO) [Resumo]Publication . García-Lobón, J. L.; Merino-Martínez, E.; Rodrigues, José Feliciano; Fernández, J.; Viruete, Javier Escuder; Pereira, E.; Carvalho, João; Batista, Maria Joao; Lisboa, Jose; Martín-Banda, Raquel; Francés, Alain Pascal; Ramalho, Elsa; Ferreira, E.; Martín-Méndez, I.; Rey-Moral, Carmen; Feria, María Carmen; Mochales, Tania; Cuervo, I.; Victorino, Américo da Mata; Manuel, JoséRESUMEN: El Plan Nacional de Geología de Angola (PLANAGEO) ha sido uno de los proyectos geotemáticos internacionales más importantes de las últimas décadas. El proyecto fue lanzado por Gobierno de la República de Angola e implementado por el Instituto Geológico de Angola (IGEO), bajo la supervisión del Ministerio de Recursos Minerales, Petróleos y Gas (MIREMPET). Los principales objetivos de PLANAGEO fueron: a) profundizar en el conocimiento de los recursos geológicos; b) fomentar la diversificación de la economía; y, c) atraer inversión extranjera para promover el desarrollo socioeconómico del país. Tras licitación internacional, el IGEO otorgó al consorcio UTE PLANAGEO, formado por el Instituto Geológico y Minero de España (IGME), el Laboratorio Nacional de Energía y Geología de Portugal (LNEG) y la empresa Impulso Industrial Alternativo (IIA) la ejecución del proyecto en la zona sur de Angola, en un área aproximada de 480.000 km2. El contrato se firmó en octubre de 2013, por un importe de 115.312.500 USD, y los trabajos cartográficos fueron realizados entre 2014 y 2022. El proyecto incluyó el levantamiento aerogeofísico regional (mag/rad) y la cartografía geológica a escala 1:250.000 de todo el país, junto con otras cartografías de detalle a escala 1:100.000, y síntesis a escalas 1:500.000 y 1:1.000.000. Fueron realizadas campañas de prospección geoquímica a escala 1:250.000, y otros estudios específicos a escala 1:50.000, que incluyeron Mapas de Recursos Minerales Metálicos (CRMMA) y Mapas de Rocas y Minerales Industriales (CARMINA) en zonas de especial interés, así como estudios hidrogeológicos en la cuenca del Kalahari.
- Modelización magnética del Complejo de Cunene (SW Angola) [Resumo]Publication . Mochales, Tania; Merino-Martínez, E.; Rey-Moral, Carmen; Machadinho, Ana; Carvalho, João; Represas, Patricia; García-Lobón, J. L.; Feria, María Carmen; Martín-Banda, Raquel; López-Bahut, T.; Alves, Daniela; Ramalho, Elsa; Manuel, José; Cordeiro, DomingosRESUMEN: El Complejo de Cunene (CC) representa un extenso macizo ígneo mesoproterozoico compuesto por rocas anortosíticas, gabroicas y ácidas contemporáneas, que aflora 18.000 km2 en dirección NNE-SSW desde el SW de Angola al NW de Namibia. Se han interpretado y modelizado en 2,5/3D los datos aerogeofísicos obtenidos en el proyecto PLANAGEO para investigar los límites no expuestos del CC, reconstruyendo la estructura de la corteza superficial bajo la cobertera del Kalahari. Gracias a la modelización se descifra una geometría lobular cuya extensión es casi tres veces la superficie aflorante y superior a la estimada mediante gravimetría (45.000 km2; Rey-Moral et al., 2022). Las anomalías magnéticas identificadas definen cuerpos individuales que conforman diversos pulsos magmáticos coalescentes durante el Mesoproterozoico. Las lineaciones magnéticas indican grandes sistemas de cizallamiento desarrollados en varias fases intrusivas en un contexto colisional de arco. Los lineamientos magnéticos al E sugieren un emplazamiento asociado a etapas transtensivas. Al W, con los pulsos más jóvenes, se detectan lineamientos en un régimen contraccional complejo. Estructuras tardías NNW-SSE extensionales, involucran magmas mantélicos y cuencas mesoproterozoicas tardías (<1,33 Ga).
- Recording the largest gabbro-anorthositic complex worldwide: The Kunene Complex (KC), SW AngolaPublication . Rey-Moral, Carmen; Mochales, Tania; Martinez, Enrique Merino; Lobón, Jose Luis Garcia; Bahut, María Teresa López; Martín-Banda, Raquel; Feria, María Carmen; Ballesteros, Dianne; Machadinho, Ana; Alves, DanielaABSTRACT: The Kunene Complex (KC) represents a large Mesoproterozoic igneous body, mainly composed of anorthosites and gabbroic rocks that extends from SW Angola to NW Namibia (18000 km2, N-S trend, and ca. 350 km long and 25???50 km wide). Although the KC has been studied from a cartographic and geochemical point of view, little is known about its structure at depth below the sedimentary deposits of the Kalahari basin. Hence, we use available satellite gravity data to estimate its extent and to unravel its morphology at depth. The Bouguer anomaly map depicts a gravity gradient from the coast (+200 mGal) towards eastern Angola (-150 mGal), which is explained by the transition from a young, dense and thin basaltic oceanic crust, formed during the Mesozoic Atlantic rifting, to an old, light and thick Archaean to Proterozoic continental crust (Congo Craton), to the east. The outcropping KC interrupts the gravity trend, showing at the western, southwestern and northeastern sides, several positive and isolated gravity anomalies linked to gabbroic intrusions associated to KC (ca. 50 km wavelength and -90 mGal). In contrast, the anomalies found at the central part of the massif (50 km wavelength and < -110 mGal) correspond to the dominant anorthositic members, according to the spatial correlation of the mapping. Five 2.5D gravity profiles have been modelled to investigate the unexposed eastern boundary, reconstructing the surface crustal structure (between 0 and 15 km depth) overlaid by the thin sedimentary cover of the Kalahari basin. The gravity modelling helps us to show that the KC was emplaced in the Upper Crust and extends in depth up to ca. 6 km, showing a lobular geometry and following a large NE-SW to NNE-SSW linear trend, presumably inherited from older Palaeoproterozoic structures. The lateral continuation of the KC to the east (between 50 and 125 km) beneath the Kalahari sediments suggests an overall size of at least twice the outcropping dimension (about 42500 km2). This statement clearly influences in the economic potential of this massif, related to the prospecting of raw materials and certain types of economic mineralization (Fe-Ti oxides, metallic sulphides or platinum group minerals).