Caracterização geoquímica e de proveniência da Formação Corumbataí (Permiano, Bacia do Paraná, Brasil)
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Data
2019-11-11
Autores
Montibeller, Cibele Carolina
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Universidade Estadual Paulista (Unesp)
Resumo
A Formação Corumbataí é uma unidade sedimentar pelítica a psamo-pelítica de idade permiana, pertencente à Supersequência Gondwana I da Bacia do Paraná, sobre a qual poucos estudos foram realizados quanto à proveniência e suas implicações paleoambientais. Este trabalho visa preencher estas lacunas, apresentando correlações de composição e de proveniência entre seções aflorantes da Formação Corumbataí nos município de Rio Claro (SP), Santa Rosa de Viterbo (SP) e Mineiros (GO), e uma seção aflorante da Formação Serra Alta (Permiano da Bacia do Paraná, correlacionável com a base da Formação Corumbataí) no município de Cesário Lange (SP), bem como suas implicações paleoclimáticas, paleogeográficas e possíveis implicações na compreensão dos mecanismos de abertura do Atlântico Sul. Os dados mostram que as rochas permianas sobrejacentes à Formação Irati que ocorrem nas áreas de estudo são classificadas quimicamente com mais frequência como “wackes” e litoarenitos, formados por sedimentos derivados predominantemente de rochas sedimentares e/ou metassedimentares e ígneas ácidas, com a região de Cesário Lange discordando das demais regiões por indicar contribuição exclusiva de rochas supracrustais. Em se tratando das amostras da Formação Corumbataí, a maturidade química e textural aumenta de norte em direção a sul, bem como o grau de submissão dos sedimentos originais ao processo de reciclagem sedimentar. As rochas sedimentares foram depositadas em ambientes tectonicamente quiescentes, enquanto os ambientes tectônicos geradores das rochas fontes variam de margens ativas ao norte da Bacia para arcos de ilhas ao sul da bacia, assim como o clima vigente nas áreas de transporte e deposição varia de úmido a norte para árido a sul, na região de Rio Claro. Em se tratando das amostras da Formação Serra Alta (provenientes de Cesário Lange), observa-se que discordam das tendências apresentada pelas demais áreas estudadas. Uma interpretação possível para as características observadas é que a Formação Corumbataí represente o início da flexura que levou à separação dos continentes Sul-Americano e Africano, e que corresponda a uma sucessão de ambientes com distintas áreas fontes ao redor da Bacia, e sugerindo, portanto, que a “Bacia Corumbataí” seja considerada distinta da sucessão entre as Formações Serra Alta, Teresina e Rio do Rastro, consideradas atualmente diretamente correlacionáveis.
The Corumbataí Formation is a pelitic to psammo-pelitic sedimentary unit of Permian age, belonging to the Gondwana I Supersequence of the Paraná Basin, about which few studies have been conducted regarding its provenance and its paleoenvironmental implications. This work aims to fill these gaps, presenting correlations of composition and provenance between outcropping sections of the Corumbataí Formation in the municipalities of Rio Claro (SP), Santa Rosa de Viterbo (SP) and Mineiros (GO), and an outcropping section of the Serra Alta Formation (Permian of the Paraná Basin, correlated with the base of the Corumbataí Formation) in the municipality of Cesário Lange (SP), as well as its paleoclimatic and paleogeographic implications and possible implications in the understanding of the opening mechanisms of the South Atlantic. The data show that the Permian rocks overlying the Irati Formation that occur in the study areas are most commonly chemically classified as “wackes” and lithoarenites, formed by sediments derived predominantly from sedimentary and/or metasedimentary and acidic igneous rocks, with Cesário Lange region disagreeing with the other regions as it indicates exclusive contribution of supracrustal rocks. Regarding the Corumbataí Formation samples, the chemical and textural maturity increases from north to south, as well as the degree of submission of the original sediments to the sedimentary recycling process. The sedimentary rocks have been deposited in tectonically quiescent environments, while source rock-generating tectonic environments range from active margins in the north of the Basin to island arches to the south, as well as the prevailing climate in the transport and deposition areas varies from humid in the north to arid in the south, in the Rio Claro region. Regarding the samples of the Serra Alta Formation (from Cesário Lange), it is observed that they disagree with the trends presented by the other studied areas. A possible interpretation of the observed characteristics is that the Corumbataí Formation represents the beginning of the flexure that led to the rupture between the South American and African continents, and corresponds to a succession of environments with distinct source areas around the Basin, and thus suggesting that the “Corumbataí Basin” must be considered distinct from the succession between the Serra Alta, Teresina and Rio do Rastro Formations, considered directly-related nowadays.
The Corumbataí Formation is a pelitic to psammo-pelitic sedimentary unit of Permian age, belonging to the Gondwana I Supersequence of the Paraná Basin, about which few studies have been conducted regarding its provenance and its paleoenvironmental implications. This work aims to fill these gaps, presenting correlations of composition and provenance between outcropping sections of the Corumbataí Formation in the municipalities of Rio Claro (SP), Santa Rosa de Viterbo (SP) and Mineiros (GO), and an outcropping section of the Serra Alta Formation (Permian of the Paraná Basin, correlated with the base of the Corumbataí Formation) in the municipality of Cesário Lange (SP), as well as its paleoclimatic and paleogeographic implications and possible implications in the understanding of the opening mechanisms of the South Atlantic. The data show that the Permian rocks overlying the Irati Formation that occur in the study areas are most commonly chemically classified as “wackes” and lithoarenites, formed by sediments derived predominantly from sedimentary and/or metasedimentary and acidic igneous rocks, with Cesário Lange region disagreeing with the other regions as it indicates exclusive contribution of supracrustal rocks. Regarding the Corumbataí Formation samples, the chemical and textural maturity increases from north to south, as well as the degree of submission of the original sediments to the sedimentary recycling process. The sedimentary rocks have been deposited in tectonically quiescent environments, while source rock-generating tectonic environments range from active margins in the north of the Basin to island arches to the south, as well as the prevailing climate in the transport and deposition areas varies from humid in the north to arid in the south, in the Rio Claro region. Regarding the samples of the Serra Alta Formation (from Cesário Lange), it is observed that they disagree with the trends presented by the other studied areas. A possible interpretation of the observed characteristics is that the Corumbataí Formation represents the beginning of the flexure that led to the rupture between the South American and African continents, and corresponds to a succession of environments with distinct source areas around the Basin, and thus suggesting that the “Corumbataí Basin” must be considered distinct from the succession between the Serra Alta, Teresina and Rio do Rastro Formations, considered directly-related nowadays.
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Palavras-chave
Gondwana I, Permiano, Bacia do Paraná, Litogeoquímica, Geoquímica de sequências sedimentares, Permian, Parana Basin, Lithogeochemistry, Sedimentary sequence geochemistry