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Contribution to the knowledge of dinoflagellate cysts from the Upper Cretaceous of Portugal: study of lagoonal associations from the Cenomanian of Nazaré.
... Na sua generalidade, as associações de dinoquistos presentes nas amostras e a repartição vertical dos seus taxa apontam para um intervalo dentro do Cenomaniano médio, corroborado pelos dados já conhecidos de foraminíferos e macroinvertebrados (Berthou, 1973(Berthou, , 1984Lauverjat, 1982;Callapez, 1998Callapez, , 2008Callapez et al., 2014). Não obstante, a presença de Trithyrodinium suspectum parece indicar uma idade dentro do Cenomaniano superior, de acordo com dados conhecidos para o hemisfério norte (Williams et al., 2004;Oliveira, 2017). Dada a contradição com a informação integrada dos restantes grupos taxonómicos, sugere-se a necessidade de revisão da primeira ocorrência (PO) deste táxon no Cretácico Superior europeu. ...
... (d) Florentinia mantellii, amostra Naz 66, slide a, R32/0; (e) Florentinia sp., amostra Naz 57, slide a, V16/1; (f) Grupo Sentusidinium, amostra Naz 59B, slide a, V25/1; (g) Heterosphaeridium sp., amostra T1, slide T1.1; (h) Palaeohystrichophora infusorioides, amostra Naz 49, slide a, X22/2; (i) Spinidinium sp., amostra Naz 59B, slide a, V37/0; (j) Spiniferites ramosus, amostra Naz 66, slide a, E36/0; (k) Subtilisphaera sp., amostra Naz 43, slide a, T30/3; (l) Trithyrodinium suspectum, amostra T1, slide T1.1; (m) Xenascus ceratioides, amostra Naz 49, slide a, T21/3; (n) Xenascus sp., amostra Naz 49, slide a, X46/0. Imagens a, d, e, f, h, i, j, k, m, n (Fernandes, 2019); Imagem b (Bonito, 2021); Imagens c, g, l (Oliveira, 2017). Escala: 20 μm. ...
... (a) Location of study area(39º36'15.11''N; 09º4'55.26''W). Southside cliffs of the promontory of Nazaré with indication of the positioning of the succession levels. CMmiddle Cenomanian; CSupper Cenomanian; T -Turonian; (b) Stratigraphic section of the studied sedimentary succession (adapted fromCallapez et al., 2014).Oliveira (2017) studied the samples from B3 to T1, Fernandes (2019) studied the samples from Naz 43 to Naz 70, and Bonito (2021) studied the samples from Naz 72 to Naz 94. (c) Relative abundances of the different groups from the middle Cenomanian of the Nazaré promontory. ...
The post-rift Upper Cretaceous stratigraphic succession of
Portugal contains the Western Portuguese Carbonate Platform which
stands out as an extensive marine succession. This Carbonate platform is
middle Albian to early Turonian in age, contemporary of eustatic
highstands and widespread flooding of the European and North African
continental margins of the Tethys Sea. A thick fossil-rich carbonate
succession outcrops in the Nazaré promontory where middle Cenomanian
organic-rich lagoonal facies are exposed. The palynological study
performed in these facies revealed the presence of a diverse assemblage of
dinoflagellate cysts (dinocysts) composed of Subtilisphaera sp., Xenascus
sp., Sentusidinium group and Florentinia sp., several dinocyst taxa
considered new to the Portuguese Cretaceous. Moreover, this study
provides significant biostratigraphic and palaeoenvironmental data. The
dinocyst associations suggest the existence of a marginal-lagoonal
environment, located nearby an inner shelf carbonated platform, and
affected by fine-grained influxes from nearby fluvial drainage.
... Neste contexto, a Nazaré é um dos afloramentos pioneiros do estudo de quistos de dinoflagelados cenomanianos, em Portugal. Na esteira de Berthou et al. (1981), Moron (1981), Oliveira (2017), Fernandes (2019) e Bonito (2021) ampliaram o seu estudo ao Cenomaniano médio local, permitindo efetuar novas precisões sobre a biostratigrafia e paleoecologia (Fernandes et al., 2021). Neste trabalho atualizam-se os dinoquistos reportados para o Cenomaniano inferior e médio da Nazaré, perfazendo 46 taxa: (?)Bourkidinium sp. ...
The promontory of Nazaré is a key section to study the Upper Cretaceous series of the West Portuguese Margin of Iberia. Special emphasis goes to the Cenomanian-Turonian West Portuguese Carbonate Platform, whose fossil rich facies outcrop extensively in the coastal cliffs. Nazaré is also one the few sections were studies on Cenomanian dinocysts were made. Present work updates a checklist 46 early to mid-Cenomanian taxa, which are related to alluvial and tidal flat environments with lagoonal areas that preceded the major early late Cenomanian transgressive event with Neolobites assemblages.
... O LNEG, em particular o Laboratório de Palinologia, conta ainda com uma equipa de palinoestratigrafia permanente formada por uma investigadora, uma técnica superior e uma assistente técnica de apoio laboratorial. A existência deste núcleo de Palinologia permite estabelecer um intercâmbio e cooperação frequentes com estudantes de mestrado e doutoramento entre instituições nacionais e estrangeiras (p.e., Borges, 2012, Lopes, 2013Costa, 2015;Oliveira, 2017;Vaz, 2017;Correia, 2018;Vilas Boas, 2018;Mulanda, 2020, Rocha, 2021Descamps, 2021). ...
Numerosos estudos palinoestratigráficos, realizados sobretudo
na Zona Sul Portuguesa, iniciados durante os anos 90 do século passado e
que se expandiram durante os anos 2000 com a extensão da investigação
para outras bacias sedimentares, permitiram detalhar
bioestratigraficamente diversas sequências estratigráficas do País. Com o
objetivo de preservar e difundir as coleções de lâminas resultantes, o
património e o conhecimento imaterial destas investigações, o Laboratório
Nacional de Energia e Geologia (LNEG) desenvolveu a PALINOTECA
LNEG, que constitui um importante arquivo científico nacional. A
PALINOTECA LNEG permite não só organizar e armazenar as lâminas
resultantes dos estudos palinoestratigráficos, como aceder a um amplo
banco de dados palinológicos indexados e em rede. Estas coleções estão
em permanente atualização, contando atualmente com cerca de 14000
lâminas registadas e cerca de 2500 para serem adicionadas. Estas coleções
são o resultado de inúmeras atividades de pesquisa palinoestratigráfica e
também de ensino de palinologia, contando com uma vasta diversidade de
grupos de palinomorfos obtidos em estudos nacionais e internacionais.
Dinoflagellates are microorganisms, essentially single-celled, which together with other phytoplankton produce food for larger organisms and occupy most aquatic environments, from freshwater habitats and brackish to marine plankton. They present a great variety of vital strategies, being sensitive to temperature and salinity, oxygenation, luminosity and availability of mineral nutrients in the environment. Certain species of dinoflagellates can produce resting stages, called dinoflagellate cysts or dinocysts, settling on sediments. These cysts are made up of chemically inert material, allowing their fossil record. They are a biostratigraphical tool of great value, in addition to serving as paleobiogeographic and paleoenvironmental indicators. Pais (1978) made the first characterization of fossil dinoflagellates in Portugal and, since then, the number of studies in the national territory has been growing. The first works essentially present photographic documentation and/or brief descriptions, and sometimes they use dinocysts as biostratigraphical markers. Since the beginning of this century, information has been enriched with important researches. Detailed biostratigraphical studies have been carried out, correlations have been established between the biostratigraphy of dinocysts and other fossiliferous groups, correlations have been made with other sedimentary basins in the country and from the planet, litho- and chemostratigraphic profiles were built based on geochemical analyzes, palinofacies were studied and paleoenvironments and paleogeography were analyzed and characterized. In the present work, we propose to present a synthesis of the scientific studies documented and inventoried with these microfossils in national territory and the important knowledge that has been obtained, still getting useful information for the research and exploration of energy resources.
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