59 documents found, page 1 of 6
Pre-Mesoproterozoic crustal framework and Mesoproterozoic evolution of the SW A...
Merino-Martínez, E.; Ferreira, Ezequiel; Valverde-Vaquero, Pablo; Rodrigues, José Feliciano; Escuder-Viruete, Javier; Garcia-Lobon, Jose LuisABSTRACT: 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 Precamb...
Pre-Mesoproterozoic crustal architecture and implications for the Mesoproterozo...
Merino-Martínez, E.; Ferreira, Ezequiel; Valverde-Vaquero, Pablo; Rodrigues, José Feliciano; Escuder-Viruete, Javier; Garcia-Lobon, Jose LuisABSTRACT: 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), b...
Zircon U-Pb and Lu-Hf Constraints on the Paleo- to Mesoproterozoic Evolution of...
Ferreira, Ezequiel; Lehmann, Jeremie; Rodrigues, José Feliciano; Hayes, Ben; Merino-Martinez, Enrique; Milani, Lorenzo; Bybee, Grant M.ABSTRACT: 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...
From source to surface: clues from garnet-bearing Carboniferous silicic volcani...
Cravinho, André; Rosa, Diogo; Relvas, Jorge M.R.S.; Solá, A. Rita; Pereira, Inês; Paquette, J. L.; Borba, M. L.; Tassinari, Colombo C. G.; Chew, DavidABSTRACT: This work investigates the relationships between partial melting, melt extraction, pluton growth and silicic volcanism in garnet-bearing felsic volcanic rocks that were extruded in the Iberian Pyrite Belt, at ca. 345 Ma. The garnets are of peritectic origin, displaying textural and chemical features of disequilibrium crystallization during partial melting reactions involving biotite at high temperatur...
The bimodal Fii-A2-type and calc-alkaline volcanic sequence of the Aljustrel br...
Lains Amaral, João; Solá, A. Rita; Santos, Telmo M. Bento Dos; Feitoza, L. M.; Tassinari, Colombo C. G.; Crispim, Lourenço; Chichorro, MartimABSTRACT: The Iberian Pyrite Belt (IPB) is a late Devonian- Early Carboniferous world-class polymetallic VMS province that includes significant Cu-(Sn)-Pb-Zn-(Ag) deposits of massive sulphides and feeder zones. The Aljustrel brownfield region contains one of the highest concentrations of ore in the IPB in 6 known deposits (Gaviao, Sao Joao, Moinho, Algares, Estacao and Feitais). To delve into the petrogenesis o...
From source to surface: clues from garnet-bearing Carboniferous silicic volcani...
Cravinho, André; Rosa, Diogo; Relvas, Jorge M.R.S.; Solá, A. Rita; Pereira, Inês; Paquette, J. L.; Borba, M. L.; Tassinari, Colombo C. G.; Chew, DavidABSTRACT: This work investigates the relationships between partial melting, melt extraction, pluton growth and silicic volcanism in garnet-bearing felsic volcanic rocks that were extruded in the Iberian Pyrite Belt, at ca. 345 Ma. The garnets are of peritectic origin, displaying textural and chemical features of disequilibrium crystallization during partial melting reactions involving biotite at high temperatur...
Zircon U-Pb and Lu-Hf isotopes reveal the crustal evolution of the SW Angolan S...
Ferreira, Ezequiel; Lehmann, Jeremie; Rodrigues, José Feliciano; Hayes, Ben; Merino-Martinez, Enrique; Milani, Lorenzo; Bybee, Grant M.ABSTRACT: 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 investigate the age and provenance of extensive sedimentary strata in southwestern Angola and use it as a proxy to gain insight into the Archean to Mesoproterozoic evolution of the region. Mesoproterozoic maximum depositional ages for the ...
O magmatismo mais antigo da Faixa Piritosa Ibérica: dados geocronológicos UPb d...
Feitoza, L. M.; Santos, Telmo M. Bento Dos; Amaral, Joao Lains; Solá, A. Rita; Tassinari, Colombo C. G.; Basei, M.A.S.; Matos, João XavierSUMMARY: New U-Pb geochronological data (SHRIMP/LA-ICP-MS) is presented for zircons of volcanic rocks and dark shales of the Salgadinho deposit, located in Cercal, Iberian Pyrite Belt. Results show that the main magmatic event was placed between 387-392 Ma, indicating the oldest volcanism in the Iberian Pyrite Belt so far. Inherited and detrital zircon ages suggest affinity to Laurussian and Avalonia (s.l.) per...
The paleoenvironmental and thermal histories of the Permian Irati formation sha...
Rocha, Rocha, H.V.; Sant'Anna, L.G.; Rodrigues, Cristina F.A.; Mendes, Márcia; Pereira, Zélia; Lopes, Gilda; Fernandes, Paulo; Pereira, EgbertoABSTRACT: Mineralogical assemblages and organofacies are important sources of information to recover the paleoenvironmental and thermal histories of shale deposits. In this study, a detailed qualitative and quantitative characterization of the Permian Irati Formation (Assistência Member) shale is based on mineralogical (XRD and SEM-EDS) and organic components (TOC, Rock-Eval pyrolysis, organofacies, TAI, fluore...
Tracking hydrothermal events using zircon REE geochemistry from the Carajás Min...
Borba, Maurício L.; Tassinari, Colombo C. G.; Matos, Fernando M. V.; Sato, Kei; Huhn, Sergio; Ferreira, Samuel N.; Medeiros, Carlos A.Zircon geochemistry and geochronology are powerful tools in the study of multistage cratonic settings, yielding information on ages and distinguishing terranes. The Caraj´ as Mineral Province (CMP) SE of the Amazonian Craton is renowned for its complex tectonic evolution and notable mineral deposits endowment, such as the giant iron-oxide-copper-gold (IOCG)-type Sossego and Salobo. Tectonic, magmatic, metamorph...