Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil
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| Format: | Artículo científico |
| Language: | en |
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Academia Brasileira de Ciências
2007
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| author | Afonso C.R. Nogueira |
| author_facet | Afonso C.R. Nogueira |
| contents | Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil Afonso C.R. Nogueira Claudio Riccomini Alcides N. Sial Multidisciplinaria (Ciencias Naturales y Exactas) Ediacaran glaciation Araras Group Amazon Craton Guia Formation After the late Cryogenian glaciation the central region of Brazil was the site of extensive deposition of platformalcarbonates of the Araras Group. This group includes a basal cap carbonate sequence succeeded by transgressive, deepplatform deposits of bituminous lime mudstone and shale. Facies and stratigraphic data combined with carbon andoxygen 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 beltand with other units worldwide. The studied succession consists of 150 m thick tabular beds of black to grey limemudstone and shale with predominantly negative δ13CPDB values around 2.5 to −1◦/◦◦ . The δ13CPDB profile ofGuia syncline shows a clear correlation with the upper portion of Guia Formation in the Cáceres region, about 200 kmto the southwest. The δ13CPDB profile of the Araras Group is comparable with δ13CPDB profiles of Ediacaran unitsof the southern Paraguay Belt, western Canada, and the Congo and Kalahari cratons. Moreover, facies distribution,stratigraphy and the carbon isotopic profile of the Araras Group match the middle Tsumeb Subgroup in Namibia, whichreinforces the Ediacaran age assigned to the Araras Group. 2007 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32779312 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.79 |
| format | Artículo científico |
| id | redalyc_32779312 |
| institution | Redalyc |
| language | en |
| publishDate | 2007 |
| publisher | Academia Brasileira de Ciências |
| spellingShingle | Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil Afonso C.R. Nogueira Multidisciplinaria (Ciencias Naturales y Exactas) Ediacaran glaciation Araras Group Amazon Craton Guia Formation Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil Afonso C.R. Nogueira Claudio Riccomini Alcides N. Sial Multidisciplinaria (Ciencias Naturales y Exactas) Ediacaran glaciation Araras Group Amazon Craton Guia Formation After the late Cryogenian glaciation the central region of Brazil was the site of extensive deposition of platformalcarbonates of the Araras Group. This group includes a basal cap carbonate sequence succeeded by transgressive, deepplatform deposits of bituminous lime mudstone and shale. Facies and stratigraphic data combined with carbon andoxygen 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 beltand with other units worldwide. The studied succession consists of 150 m thick tabular beds of black to grey limemudstone and shale with predominantly negative δ13CPDB values around 2.5 to −1◦/◦◦ . The δ13CPDB profile ofGuia syncline shows a clear correlation with the upper portion of Guia Formation in the Cáceres region, about 200 kmto the southwest. The δ13CPDB profile of the Araras Group is comparable with δ13CPDB profiles of Ediacaran unitsof the southern Paraguay Belt, western Canada, and the Congo and Kalahari cratons. Moreover, facies distribution,stratigraphy and the carbon isotopic profile of the Araras Group match the middle Tsumeb Subgroup in Namibia, whichreinforces the Ediacaran age assigned to the Araras Group. 2007 artículo científico 0001-3765 https://www.redalyc.org/articulo.oa?id=32779312 en http://www.redalyc.org/revista.oa?id=327 Anais da Academia Brasileira de Ciências application/pdf Academia Brasileira de Ciências Anais da Academia Brasileira de Ciências (Brasil) Num.3 Vol.79 |
| title | Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil |
| topic | Multidisciplinaria (Ciencias Naturales y Exactas) Ediacaran glaciation Araras Group Amazon Craton Guia Formation |
| url | https://www.redalyc.org/articulo.oa?id=32779312 |