The oldest Ordovician foraminifers (Oepikodus evae conodont Zone, Floian) from South America

The oldest occurrences of the monothalamous foraminifer species. Amphitremoida longa Nestell and Tolmacheva and A. laevis Nestell and Tolmacheva are found in the San Juan Formation together with conodonts of the Oepikodus evae Zone of the Floian (Lower Ordovician), in the Salagasta 2 section, southe...

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Detalhes bibliográficos
Autores: Nestell, Galina, Heredia, Susana Emma, Mestre, Ana, Beresi, Matilde Sylvia, González, Mercedes
Tipo de documento: artigo
Estado:Versão publicada
Data de publicação:2011
País:Argentina
Recursos:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositório:CONICET Digital (CONICET)
Idioma:inglês
OAI Identifier:oai:ri.conicet.gov.ar:11336/139154
Acesso em linha:http://hdl.handle.net/11336/139154
Access Level:Acceso aberto
Palavra-chave:ARGENTINA
CONODONTS
FORAMINIFERS
LOWER ORDOVICIAN
PRECORDILLERA
https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
Descrição
Resumo:The oldest occurrences of the monothalamous foraminifer species. Amphitremoida longa Nestell and Tolmacheva and A. laevis Nestell and Tolmacheva are found in the San Juan Formation together with conodonts of the Oepikodus evae Zone of the Floian (Lower Ordovician), in the Salagasta 2 section, southern Precordillera, Argentina. These discoveries represent the oldest record for foraminifers in South America. The foraminifers, species of which were originally described from the Lower Ordovician of northwestern Russia, are found in shallow high energy carbonate platform deposits in the Precordillera, together with a North Atlantic province conodont fauna. The carbonate sequence of the San Juan Formation in the Salagasta region is interpreted as a succession ranging from shallower tidal deposits to carbonate crinoidal shoaling bar deposits.