Browsing by Author "Silva, J. Brandão"
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- Detrital zircons from a Late Palaeozoic accretionary complex of SW Iberia (Variscan Belt) : history of crustal growth and recycling at the Rheic convergent marginPublication . Pereira, Manuel Francisco Costa; Drost, K.; Chichorro, Martim; Silva, J. Brandão; Solá, A. Rita
- Early Cambrian granitoids of North Gondwana margin in the transition from a convergent setting to intra-continental rifting (Ossa-Morena Zone, SW Iberia)Publication . Sánchez-García, Teresa; Pereira, M. Francisco; Bellido, F.; Chichorro, Martim; Silva, J. Brandão; Valverde-Vaquero, Pablo; Pin, Ch.; Solá, A. RitaTwo distinct Cambrian magmatic pulses are recognized in the Ossa-Morena Zone (SW Iberia): an early rift-(ER) and a main rift-related event. This Cambrian magmatism is related to intra-continental rifting of North Gondwana that is thought to have culminated in the opening of the Rheic Ocean in Lower Ordovician times. New data of whole-rock geochemistry (19 samples), Sm–Nd–Sr isotopes (4 samples) and ID–TIMS U–Pb zircon geochronology (1 sample) of the Early Cambrian ER plutonic rocks of the Ossa-Morena Zone are presented in this contribution. The ER granitoids (Barreiros, Barquete, Calera, Salvatierra de los Barros and Tablada granitoid Massifs) are mostly peraluminous granites. The Sm–Nd isotopic data show moderate negative eNdt values ranging from -3.5 to +0.1 and TDM ages greatly in excess of emplacement ages. Most ER granitoids are crustal melts. However, a subset of samples shows a transitional anorogenic alkaline tendency, together with more primitive isotopic signatures, documenting the participation of lower crust or mantle-derived sources and suggesting a local transient advanced stage of rifting. The Barreiros granitoid is intrusive into the Ediacaran basement of the Ossa-Morena Zone (Série Negra succession) and has yielded a crystallization age of 524.7 ± 0.8 Ma consistent with other ages of ER magmatic pulse. This age: (1) constrains the age of the metamorphism developed in the Ediacaran back-arc basins before the intrusion of granites and (2) defines the time of the transition from the Ediacaran convergent setting to the Lower Cambrian intra-continental rifting in North Gondwana.
- Evolução estratigráfica do Sudoeste do Maciço Ibérico do Ediacariano ao Devónico inferiorPublication . Pereira, Manuel Francisco Costa; Silva, J. Brandão; Chichorro, Martim; Medina, Jorge; Solá, A. Rita
- Iberian paleogeography traced by U-Pb zircon ages of Ediacaran Cambrian rocksPublication . Solá, A. Rita; Pereira, Francisco; Chichorro, Martim; Lopes, Luis; Gerdes, Axel; Silva, J. Brandão
- Intra-crustal recycling and crustal-mantle interactions in North Gondwana revealed by oxygen isotopic composition of Neoproterozoic to Ordovician zircons from SW Iberia rocksPublication . Chichorro, Martim; Solá, A. Rita; Pereira, M. Francisco; Sánchez-García, Teresa; Ferreira, A.; Silva, J. Brandão; Armstrong, R.
- New geochemical and geochronological data of early Cambrian of SW Iberia : calc-alkaline magmatism in the transition from active to passive continental margin in North GondwanaPublication . Sánchez-García, T.; Pereira, Manuel Francisco Costa; Bellido Mulas, F.; Chichorro, Martim; Silva, J. Brandão; Valverde-Vaquero, Pablo; Pin, C.; Solá, A. Rita
- North-Gondwana assembly, break-up and paleogeography : U-Pb isotope evidence from detrital and igneous zircons of Ediacaran and Cambrian rocks of SW IberiaPublication . Pereira, Manuel Francisco Costa; Solá, A. Rita; Chichorro, Martim; Lopes, L.; Gerdes, Axel; Silva, J. Brandão
- Provenance analysis of Lower Palaeozoic siliciclastic rocks of the Southwestern Iberia (Ossa-Morena Zone) : distal shelf deposition on the North Gondwana passive marginPublication . Pereira, M. Francisco; Chichorro, Martim; Lopes, C.; Solá, A. Rita; Silva, J. Brandão; Hofmann, Mandy; Linnemann, Ulf
- Provenance analysis of Lower Paleozoic siliciclastic rocks of SW Iberia (Ossa-Morena Zone) : distal shelf deposition in the North Gondwana passive marginPublication . Pereira, Manuel Francisco Costa; Chichorro, Martim; Lopes, C.; Solá, A. Rita; Silva, J. Brandão; Hofmann, Mandy; Linnemann, Ulf
- Provenance analysis of the Late Ediacaran basins from Southwestern Iberia (Série Negra Succession and Beiras Group) : evidence for a common Neoproterozoic evolutionPublication . Chichorro, Martim; Solá, A. Rita; Pereira, M. Francisco; Hofmann, Mandy; Linnemann, Ulf; Gerdes, Axel; Medina, Jorge; Lopes, L.; Silva, J. Brandão