Browsing by Author "Montero, P."
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- 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.
- Proyecto GEO_FPI, cartografía de la Zona Surportuguesa (ZSP). Datos preliminares de un estudio geocronológico U-PbPublication . Díez-Montes, Alejandro; Matos, João Xavier; Valverde-Vaquero, Pablo; Solá, A. Rita; Beranoaguirre, Aratz; Albardeiro, Luis; Salgueiro, Rute; Morais, Igor; Montero, P.; López, M. T.RESUMEN: La ZSP es la unidad geotectónica más al suroeste del Orógeno Varisco y se consideran los siguientes dominios: Pulo do Lobo (Frasniense inferior y Fameniense superior), Faja Pirítica Ibérica (Givetiense-Viseense superior), Grupo Flysch Baixo Alen tejo (Viseense superior-Moscoviense superior) y Grupo Suroeste (Estruniense-Bashkiriense medio). En el proyecto GEO_FPI se ha prestado especial atención a la Faja Pirítica Ibérica, ya que es una de las provincias metalogenéticas más importantes del mundo, con depósitos de sulfuros masivos (VHMS) e importantes recursos de Cu, Zn, Pb, Ag, Au, Sn, In, Se, Ge. Se ha realizado un trabajo de campo en común en la región fronteriza de España y Portugal para permitir una mejor inte gración y correlación de los datos geológicos y cartográficos. Además, se han seleccionado 31 afloramientos donde se han recogido muestras para realizar un estudio de geocronología de U-Pb en circón. Los datos de edad obtenidos son importantes para restringir las estructuras geológicas de la Faja Pirítica Ibérica que albergan la mineralización masiva de sulfuros y, por otra parte, mejoran la visión geotectónica de toda la ZSP