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	Provedor de dados Anais da ABC (AABC) (2) Autor Sial,Alcides N. (2) Chiglino,Leticia (1) Ferreira,Valderez P. (1) Gaucher,Claudio (1) Nogueira,Afonso C.R. (1) Riccomini,Claudio (1) Mais... Palavra-chave Ediacaran (2) Acritarchs (1) Amazon Craton (1) Araras Group (1) Carbon and oxygen isotopes (1) Glaciation (1) Guia Formation (1) Neoproterozoic (1) Northeastern Brazil (1) Mais... Tipo do documento Info:eu-repo/semantics/article (2) Ano 2015 (1) 2007 (1) País Brazil (2) Idioma Inglês (2)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 2 Primeira ... 1 ... Última Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil Anais da ABC (AABC) Riccomini,Claudio; Nogueira,Afonso C.R.; Sial,Alcides N.. After the late Cryogenian glaciation the central region of Brazil was the site of extensive deposition of platformal carbonates of the Araras Group. This group includes a basal cap carbonate sequence succeeded by transgressive, deep platform deposits of bituminous lime mudstone and shale. Facies and stratigraphic data combined with carbon and oxygen isotopic analyses of the most complete section of the transgressive deposits, exposed in the Guia syncline, were used to evaluate the depositional paleoenvironment and to test the correlation of these deposits along the belt and with other units worldwide. The studied succession consists of 150 m thick tabular beds of black to grey lime mudstone and shale with predominantly negative delta13C PDB values around... Tipo: Info:eu-repo/semantics/article Palavras-chave: Carbon and oxygen isotopes; Ediacaran; Araras Group; Guia Formation; Amazon Craton; Glaciation. Ano: 2007 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652007000300012 Acritarchs of the Ediacaran Frecheirinha Formation, Ubajara Group, Northeastern Brazil Anais da ABC (AABC) Chiglino,Leticia; Gaucher,Claudio; Sial,Alcides N.; Ferreira,Valderez P.. We report for the first time the occurrence of organic-walled microfossils in Ediacaran limestones and marls of the Frecheirinha Formation, Ubajara Group, and the first Precambrian acritarchs so far reported for northeastern Brazil. The assemblage of the Frecheirinha Formation represents a low-diversity microflora comprising Leiosphaeridia, Lophosphaeridium and subordinated Bavlinella (=Sphaerocongregus). Their thermal alteration index (TAI) between 4+ and 5, suggests metamorphic temperatures exceeding 200-250°C. Higher temperatures are probably related to intruding granitic plutons (Meruoca, Mucambo). Reported δ13C values of carbonates of -3.5 ‰ VPDB (Vienna-Peedee Belemnite) at the base, passing up section into a positive plateau of up to +3.7 ‰, and... Tipo: Info:eu-repo/semantics/article Palavras-chave: Acritarchs; Ediacaran; Neoproterozoic; Northeastern Brazil. Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015000200635 Registros recuperados: 2 Primeira ... 1 ... Última

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