Dating kaolinite from the Neogene Içá Formation and overlying laterites, central Amazonia, Brazil: Constraints for a stratigraphic correlation

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MetadadosDescriçãoIdioma
Autor(es): dc.contributorSorbonne Université-
Autor(es): dc.contributorServiço Geológico do Brasil-
Autor(es): dc.contributorUniversidade Federal de Goiás (UFG)-
Autor(es): dc.contributorUMR7194-
Autor(es): dc.contributorUniversidade Estadual Paulista (Unesp)-
Autor(es): dc.creatorAllard, T.-
Autor(es): dc.creatorPereira, L.-
Autor(es): dc.creatorMathian, M.-
Autor(es): dc.creatorBalan, E.-
Autor(es): dc.creatorTaitson Bueno, G.-
Autor(es): dc.creatorFalguères, C.-
Autor(es): dc.creatordo Nascimento, N. R. [UNESP]-
Data de aceite: dc.date.accessioned2022-02-22T00:26:02Z-
Data de disponibilização: dc.date.available2022-02-22T00:26:02Z-
Data de envio: dc.date.issued2020-12-11-
Data de envio: dc.date.issued2020-12-11-
Data de envio: dc.date.issued2020-09-15-
Fonte completa do material: dc.identifierhttp://dx.doi.org/10.1016/j.palaeo.2020.109818-
Fonte completa do material: dc.identifierhttp://hdl.handle.net/11449/198958-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/11449/198958-
Descrição: dc.descriptionThe Neogene Içá Formation is a major sedimentary deposit in central Amazonia (Brazil) that is critical to the understanding and modeling of the evolution of the Amazon Basin. However, its chronostratigraphy is poorly defined, mostly because it is not fossiliferous and it does not contain volcanic ash levels. This study is the first attempt at the absolute dating of the sediments and overlying soils of the Içá Formation by electron paramagnetic resonance (EPR) of radiation-induced defects in kaolinite (RIDs). Four profiles of unconsolidated sediments overlaid by lateritic soils from the Barcelos region (Amazonia, Brazil) were studied. The concentration of RIDs was assessed from EPR spectra through a simplified procedure on a selected set of samples, excluding those showing too strong of interference from the signal of trace vanadyl complexes. It is shown that in such sedimentary material, both the microscopic distribution of thorium (together with uranium) and the origin of kaolinite, either detrital or authigenic, are critical for kaolinite dating. Considering an argued authigenic origin and two scenarios of Th distribution, it appears that most of the present chronologic data support the stratigraphic correlation with the Madre de Dios sedimentary Formation in Peru previously proposed in the literature for the Içá Formation (9.5–2.5 Ma). This study also shows a rejuvenation process of kaolinite both in the uppermost soil and at depth of the profiles. This rejuvenation occurred during paleoclimatic periods already revealed in other weathering covers from the Amazon Basin and possibly resulted from downward weathering in the topsoil and water table or lateral weathering at depth.-
Descrição: dc.descriptionCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)-
Descrição: dc.descriptionIMPMC UMR CNRS 7590 Sorbonne Université-
Descrição: dc.descriptionCPRM Serviço Geológico do Brasil-
Descrição: dc.descriptionUFG Universidade Federal de Goiás-
Descrição: dc.descriptionIPH UMR7194, 1 rue René Panhard-
Descrição: dc.descriptionUNESP Universidade Estadual Paulista-
Descrição: dc.descriptionUNESP Universidade Estadual Paulista-
Idioma: dc.languageen-
Relação: dc.relationPalaeogeography, Palaeoclimatology, Palaeoecology-
???dc.source???: dc.sourceScopus-
Palavras-chave: dc.subjectArtificial irradiation-
Palavras-chave: dc.subjectDosimetry-
Palavras-chave: dc.subjectElectron paramagnetic resonance-
Palavras-chave: dc.subjectGeochronology-
Palavras-chave: dc.subjectRadiation-induced defects-
Palavras-chave: dc.subjectSediments-
Título: dc.titleDating kaolinite from the Neogene Içá Formation and overlying laterites, central Amazonia, Brazil: Constraints for a stratigraphic correlation-
Tipo de arquivo: dc.typelivro digital-
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