Percorrer por autor "Escuder-Viruete, Javier"
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- 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.