Quistos de dinoflagelados no Miocénico da parte distal da Bacia do Baixo-Tejo, Portugal

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Abstract

A total of 36260 palynomorphs were identified (of which 67 taxa of dinocysts) in 111 samples from the Miocene of the distal part of the Lower Tagus Basin (nine outcrops and one borehole). The data obtained from the evolution of the associations, mainly of marine organic walled dinocysts, complements previous studies. All the samples were submitted to the standard procedure of palynological treatment. This palynological study presents the stratigraphic distribution of recognized dinoflagellate cysts. The identified associations of dinocysts present pronounced provincialism, being some of them consequence of paleoenvironmental conditions and others caused by biogeography. It was possible to identify several associations that were compared with international biozonations, in order to establish a valid biostratigraphic scale for the Portuguese Miocene. Over the past 25 years, numerous biozonations have been proposed for the Oligocene-Early Miocene, based on dinocysts in the Atlantic, North America, Europe, the North Sea, the Pacific, among others. The Cenozoic dinocysts rarely exhibit synchronous boundaries when compared with pre-Cenozoic distributions. The associations seem only to be reliable at regional level. © 2014 LNEG – Laboratório Nacional de Geologia e Energia IP.
Original languagePortuguese
Title of host publicationA Terra: conflitos e ordem
EditorsP. M. Callapez, R. B. Rocha, J. F. Marques, L. S. Cunha, P. M. Dinis
Place of PublicationCoimbra
PublisherMMGUC
Pages159-174
ISBN (Print)978-989-95994-0-6
Publication statusPublished - 2008

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