El perfil del sinclinal del Rincón Blanco (noroeste de La Rioja): el límite Carbonífero-Pérmico en el noroeste argentino
The finding of palynological associations in the Río del Peñón Formation (Late Carboniferous-Early Permian) is addressed. The fossiliferous section is located in the north of the Precordillera, more precisely at the Río Blanco place, situated to the west of the Jagüe town. The Río del Peñón Formatio...
| Autores: | , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2006 |
| País: | Argentina |
| Recursos: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | español |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/79225 |
| Acesso em linha: | http://hdl.handle.net/11336/79225 |
| Access Level: | acceso abierto |
| Palavra-chave: | ARGENTINA LA RIOJA PALEOPALINOLOGÍA BIOESTRATIGRAFÍA GEOCRONOLOGÍA LÍMITE CARBONÍFERO-PÉRMICO https://purl.org/becyt/ford/1.5 https://purl.org/becyt/ford/1 |
| Resumo: | The finding of palynological associations in the Río del Peñón Formation (Late Carboniferous-Early Permian) is addressed. The fossiliferous section is located in the north of the Precordillera, more precisely at the Río Blanco place, situated to the west of the Jagüe town. The Río del Peñón Formation (1,270 m thick) is composed of three members, the lower (729 m thick) bears 21 fossilifeous levels, whereas both the middle (161 m thick) and upper members (161 m thick) contain only 2. The lower 16 fossiliferous levels contain palynological associations referred to the Raistrickia densaConvolutispora muriornata Biozone (DM, C Sub-biozone?). The rest of the palynological levels are here included in the Pakhapites fusus-Vittatina subsaccata Biozone (FS). Moreover, in this paper the stratigraphic relationship among the palynological associations, the megafloristic NBG Biozone and the marine invertebrates assemblages described by previous authors (Tivertonia jachalensis-Streptorhynchus inaequioenatus Biozone) are also identified. The palynological information here presented and previous radiometric ages reported not only by the underlying Punta del Agua Formation (287 and 295 Ma) but also by a riodacitic sill intercalated in the lowermost part of the Río del Peñón Formation (287,8±0,7 Ma) allow to assign the Río del Peñón Formation to the uppermost part of the Upper Carboniferous-Lower Permian. Moreover, the ages of the NBG and DM Biozones are constrained to the beginning of the Permian. Finally the Rincón Blanco section is proposed as a potential stratotype for DM and FS Biozones and thus of the Carboniferous-Permian boundary. |
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