Elucidações quanto a evolução da porção central do Rift Continental do Sudeste do Brasil (RCSB): traço de fissão por microssonda eletrônica em zircões da Bacia de Taubaté e adjacências
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Data
2022-12-02
Autores
Peres, Gustavo Soldado
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Universidade Estadual Paulista (Unesp)
Resumo
O Rift Continental do Sudeste do Brasil (RCSB), apresenta uma estrutura de graben e horts preservada não recoberta por águas sendo uma importante feição para estudos geológicos, tanto pelo seu potêncial econômico quanto pelo papel evolutivo que representa para o sudeste brasileiro. O presente trabalho, se baseia na aplicação de técnicas termocronológicas por meio de traço de fissão em zircões detríticos, com objetivo de elucidar a evolução geológica da porção central do RCSB antes de sua abertura, e melhor compreender os processos de exumação durante o Paleogeno-Neogeno. Para isso utilizou-se de amostras coletadas na Bacia de Taubaté e suas adjacências, no segmento central do RSCB. As idades obtidas remontam a eventos desde o Triássico ao Cretáceo, com a fase de reativação, rifteamento do Continente Gondwana, abertura do Oceano Atlântico e Soerguimento da Serra da Mantiqueira. Para o Paleogeno-Neogeno, período deposicional da Bacia de Taubaté e surgimento do RSCB a disposição dos picos de idade para os sedimentos da bacia, oriundos de áreas fonte distintas, evidenciam processos de estabilidade nas taxas de exumação e aumento da mesma ao longo do tempo. Cálculos de taxa de lag-time revelam uma diferença do tempo de trajeto dos grãos para diferentes localidades da bacia, aliados aos diferentes picos de idades esses dados corroboram para existência de mais de uma área fonte com expressividade no aporte de sedimentos.
The Continental Rift of Southeastern Brazil (RCSB), presents a preserved graben and horts structure not covered by water and is an important feature for geological studies, both for its economic potential and for the evolutionary role it represents for southea stern Brazil. The present work is based on the application of thermochronological techniques by means of fission tracks in detrital zircons, in order to elucidate the geological evolution of the central portion of the RCSB before its opening, and to better understand the exhumation processes during the PaleogeneNeogene. For this purpose, samples collected in the Taubaté Basin and its surroundings, in the central segment of the RSCB, were used. The ages obtained date back to events from the Triassic to the Cretaceous, with the reactivation phase, rifting of the Gondwana continent, opening of the Atlantic Ocean and soaring of the Mantiqueira mountain range. For the PaleogeneNeogene, depositional period of the Taubaté Basin and emergence of the RSCB the dispo sition of the age peaks for the basin sediments, coming from distinct source areas, shows processes of stability in the exhumation rates and increase of the same through time. The lagtime rate calculations reveal a difference in the grain travel time for different locations in the basin, together with the different peak ages, these data corroborate the existence of more than one source area with expressivity in the sediment contribution.
The Continental Rift of Southeastern Brazil (RCSB), presents a preserved graben and horts structure not covered by water and is an important feature for geological studies, both for its economic potential and for the evolutionary role it represents for southea stern Brazil. The present work is based on the application of thermochronological techniques by means of fission tracks in detrital zircons, in order to elucidate the geological evolution of the central portion of the RCSB before its opening, and to better understand the exhumation processes during the PaleogeneNeogene. For this purpose, samples collected in the Taubaté Basin and its surroundings, in the central segment of the RSCB, were used. The ages obtained date back to events from the Triassic to the Cretaceous, with the reactivation phase, rifting of the Gondwana continent, opening of the Atlantic Ocean and soaring of the Mantiqueira mountain range. For the PaleogeneNeogene, depositional period of the Taubaté Basin and emergence of the RSCB the dispo sition of the age peaks for the basin sediments, coming from distinct source areas, shows processes of stability in the exhumation rates and increase of the same through time. The lagtime rate calculations reveal a difference in the grain travel time for different locations in the basin, together with the different peak ages, these data corroborate the existence of more than one source area with expressivity in the sediment contribution.
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Geologia, Termocronologia detrítica, Traço de fissão, RCSB, Geology, Detrital Zircon Termocronhology, Zircon fission track