Browsing by Author "Sequeira, A. J. D."
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- Dados palinoestratigráficos preliminares do Gorstiano (Silúrico) da Formação de Sazes (Sinclinal do Buçaco)Publication . Lopes, Gilda; Vaz, Nuno; Sequeira, A. J. D.; Piçarra, J. M.; Fernandes, Paulo; Pereira, ZéliaNovos dados bioestratigráficos foram obtidos na sucessão estratigráfica do Paleozóico Inferior da região do Buçaco. A Formação de Sazes (Silúrico) está a ser estudada ao nível palinológico (miosporos e quitinozoários) e de macrofósseis (graptólitos), com o intuito de rever e complementar dados bioestratigráficos anteriormente descritos. Com base nos dados palinológicos, parte da Fm. de Sazes foi datada com mais precisão como pertencendo ao Gorstiano e, pela primeira vez nesta região, também foram identificados criptosporos. Novos dados são esperados com a continuação deste estudo.
- New insights on the Hirnantian palynostratigraphy of the rio Ceira section, Buçaco, PortugalPublication . Lopes, Gilda; Vaz, Nuno; Sequeira, A. J. D.; Piçarra, J. M.; Fernandes, Paulo; Pereira, Zélia; Gutierrez-Marco, J. C.; Rabano, I.; Garcia-Bellido, D.The Lower Palaeozoic successions of Portugal are well represented in the Central Iberian Zone (Cll), one of the main tectonostratigraphic domains of the Iberian Massif. Located in the CIZ, the Bu<;aco Syncline presents one of its most complete Palaeozoic sequences. With a NW-SE orientation, the Lower Palaeozoic lithostratigraphic succession, includes several Ordovician units that ranges from the Lower Ordovician (Tremadocian stage) to the Upper Ordovician (Hirnantian stage) and are unconformably overlain by the Silurian Sazes Formation, at least of Wenlock and Ludlow epochs, in the Rio Ceira Section (Fig.1). This sequence is also well known by its rich palaeontological content in macrofauna (e.g. trilobites, briozoans, echinoderms, ostracods, brachiopods, graptolites) and microfauna (conodonts, chitinozoans, acritarchs) (Delgado, 1908; Henry and Thadeu, 1971; Mitchell, 1974; Henry et al., 1974, 1976; ElaouadDebbaj, 1978; Henry, 1980; Paris, 1979, 1981; Romano, 1982; Romano et aI., 1986; Young, 1985, 1987, 1988,1989).
- Palynomorphs from the Gorstian (Silurian) of the Sazes Formation (Buçaco Syncline), Central Iberian Zone, Portugal - preliminary resultsPublication . Lopes, Gilda; Vaz, Nuno; Sequeira, A. J. D.; Piçarra, J. M.; Fernandes, Paulo; Pereira, ZéliaOccuring in a complex syncline that extends from Buçaco to Penedo de Góis, the studied area is located in the Central Iberian Zone of the Iberian Massif. In this region outcrops a well-preserved and complete stratigraphic succession of Lower Paleozoic age. At the top of the Buçaco Syncline stratigraphic succession, the Silurian Sazes Formation (Paris, 1981), is currently being studied at a palynological (miospores and chitinozoans) and macrofossil (graptolites) level, allowing a preliminary revision and completion of the initial biostratigraphy of this area. This studies will also provide information to support the undergoing surveying mapping project (1:50 000) that is being undertaken by the “Laboratório Nacional de Energia e Geologia” (Portuguese Geological Survey) (Sequeira, in prep).