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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.
- Zircon U-Pb and Lu-Hf Constraints on the Paleo- to Mesoproterozoic Evolution of the Southwest Angolan Shield (Congo Craton) [Resumo]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 determine the age and provenance of extensive sedimentary strata in southwest Angola, and use them as a proxy for the Paleoproterozoic to Mesoproterozoic evolution of the southwest AS. Mesoproterozoic maximum depositional ages between 1334 ± 8 Ma and 1184 ± 23 Ma for the Iona, Cahama, and Ompupa siliciclastic rocks refute previous correlations with the Paleoproterozoic Chela Group. Detrital zircon U-Pb and Lu-Hf isotopes closely match those of magmatic rocks from the southwest AS, indicating that Mesoproterozoic siliciclastic rocks were primarily derived from the AS.
- Namibe Group detrital zircon U-Pb and Lu-Hf isotopes: a testimony of late-Orosirian (1.9–1.8 Ga) crustal growth in the Angolan Shield (Congo Craton)Publication . Ferreira, Ezequiel; Lehmann, Jeremie; Rodrigues, José Feliciano; Silva, Paulo Bravo; Smith, Trishya M. Owen; García-Lobón, J. L.; Correia, João; Ueckermann, Henriette; Molekwa, Mmasetena Anna; Manuel, José; Victorino, Américo da MataABSTRACT: The Namibe Group represents the largest package of immature supracrustal rocks of the Angola Shield (Congo Craton), occupying an area of nearly 10,000 km2 in the Namibe Zone (NZ). It is a folded, steeply dipping, meta-volcanosedimentary sequence essentially comprising immature micaschists and greywackes, felsic metavolcaniclastites, along with intercalated marbles and amphibolites. The metavolcanosedimentary sequence is intruded by ca. 1810–1790 Ma ultramafic to felsic plutonic rocks with magmatic arc geochemical signatures. Despite its importance, key aspects such as its maximum depositional age (MDA), sedimentary provenance, and the detrital zircon (DZ) record of crustal evolution remain unresolved. This study presents LA-ICP-MS U-Pb and Lu-Hf DZ analyses from nine NG samples.
- Lower Cretaceous palynology and palaeoenvironments of Algarve Basin: the Arrifes sectionPublication . Mendes, Márcia; Descamps, G.S.; Fernandes, Paulo; Lopes, Gilda; Jorge, Raul CG Santos; Pereira, ZéliaSUMÁRIO: Uma análise sedimentológica e palinológica detalhada foi realizada na secção dos Arrifes, uma sucessão do Cretácico Inferior da Bacia do Algarve (sul de Portugal). A sucessão estudada é composta por calcários fossilíferos intercalados, calcários margososos e margas, sendo que os palinomorfos identificados indicam uma idade entre o Hauteriviano superior e o Barremiano superior. As principais características deposicionais e palinológicas documentadas na secção dos Arrifes sugerem uma deposição geral sob condições rasas subtidais e intertidais, marcadas por pequenas mudanças climáticas com múltiplas oscilações do nível do mar. Face a estes novos resultados, a área foi correlacionada com outras secções circundantes do Cretácico Inferior, sugerindo uma influência Tethyana durante o Hauteriviano superior, prolongando-se até ao final do Barremiano.
- Wyllieite reaction coronas on scorzalite in pegmatite dykesPublication . Dias, Patrícia; Gomes, Carlos Augusto Alves Leal; Guimarães, Fernanda; Hatert, Frederic
- Caracterização de teores em cobre nos solos e sedimentos na envolvente à Mina de AljustrelPublication . Guimarães, T.; Almeida, J. A.; Brito, M. G.; Salgueiro, Rita; Silva, E.; Candeias, Carla; Ávila, Paula Freire
- Mining activities in Panasqueira area : impact and threats in ecosystems and human health in rural communitiesPublication . Candeias, Carla; Silva, Eduardo Ferreira da; Ávila, Paula Freire; Coelho, Patrícia; Teixeira, João Paulo
- Ab-initio simulations for the Cu-Sb-S systemsPublication . Ferreira, Jorge Amaral; Braga, Maria Helena
- Neutron scattering and ab-initio simulations to characterize the Cu-Li-Mg-H systemsPublication . Braga, Maria Helena; Wolverton, Michael J.; Ferreira, Jorge Amaral; Daemen, Luc L.
- Treatment of groundwater contaminated by arsenic using iron oxides/hydroxidesPublication . Azevedo, Irene; Silva, Maria Aurora Soares; Freitas, Olga; Figueiredo, Sónia; Ferreira, Adelaide; Fiúza, António
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