Étude petrologique et cristallochimique du kaolin de La rivière Capim – Pará, Brésil

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MetadadosDescriçãoIdioma
Autor(es): dc.contributorVarajão, Angélica Fortes Drummond Chicarino-
Autor(es): dc.creatorSousa, Daniel José Lima de-
Data de aceite: dc.date.accessioned2019-11-06T13:30:06Z-
Data de disponibilização: dc.date.available2019-11-06T13:30:06Z-
Data de envio: dc.date.issued2014-07-18-
Data de envio: dc.date.issued2014-07-18-
Data de envio: dc.date.issued2005-
Fonte completa do material: dc.identifierhttp://www.repositorio.ufop.br/handle/123456789/3538-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/capes/556650-
Descrição: dc.descriptionPrograma de Pós-Graduação em Evolução Crustal e Recursos Naturais. Departamento de Geologia. Escola de Minas, Universidade Federal de Ouro Preto-
Descrição: dc.descriptionLe District kaolinitique du Rio Capim, localisé dans le nord du Brésil, dans la région Amazonienne, constitue un des plus importants dépôts de kaolin du monde. Connu par as blancheur élevée, ses applications concernent l’industrie de papier. Le kaolin s’est développé à partir des sédiments crétacés argilo-gréseux de la Formation Ipixuna où um intense processus latéritique ont eu lieu dés le Mesozoic au le Cenozoic. Le but de ce travail est de tracer l’évolution des faciès du kaolin du Rio Capim em considérant les aspects macro-morphologiques, minéralogiques, micro-morphologiques, texturaux cristallochimiques et chimiques. Ces études ont été réalisées sur les profils leves aux fronts de tailles de l’exploitation à ciel ouvert de la Société Imerys Rio Capim Caulim (IRCC) et les matériaux ont été analysées par chimie (ICP-MS, ICP-EAS), diffraction dês rayons-X, analyses thermiques et gravimétrique (ATD-ATG), microscopie optique, microscopie électronique à balayage (MEB-EDS) et à transmission (MET-EDS), dês analyses texturales par volumétrie d’adsorption d’azote, granulométrie par diffusion laser, des mesures de la capacité d’échange cationique (CEC), spectroscopies UV visible, spectroscopie infrarouge (IR), spectroscopie Mössbauer, L’ensemble ders données a été repris dans une étude statistiques par analyse en composantes principales (ACP) et enfin, des datations de monocristaux de zircons on été effectuées par la méthode Pb-Pb. Six faciès ont été définis (faciès grès, faciès soft, faciès de transition inférieur, fácies ferrugineux, faciès de transition supérieure, faciès flint) et reliés aux différentes étapes Du processus supergénène. Les faciès des transitions et ferrugineux sont les témoins d’um processus de ferruginisation qui a engendré la formation d’une épaisse cuirasse sur le fácies soft. Le faciès soft a été formé à partir du sédiment grès-argileux de la Formation Ipixuna (faciès grés). Le processus de ferruginisation a été suivi d‘un processus de déferruginisation à l’origine de la différenciation. La même assemblage de minéraux denses dans lês différents faciès montre que les sédiments ont une origine commune. Cette constatations a été corroboré par les études de provenances effectués sur les zircons des faciès flint et soft par la méthode de vaporisation Pb-Pb. __________________________________________________________________________________________-
Descrição: dc.descriptionABSTRACT: The Capim Kaolinic District, located in the eastern Brazilian Amazon, constitutes one of the most important kaolin deposits in the world. Known for its high whiteness, its noble application is in the paper industry. The kaolin developed at the expense of Cretaceous sandy-clayey sediments of the Ipixuna Formation, on which intense lateritic processes took place from the Mesozoic to the Cenozoic. This work aims at tracing the evolution of the Capim kaolin faciès, taking into consideration macromorphological, mineralogical, micromorphological, textural, chrystallochemical and geochemical studies. These studies, based on the description of profiles in the exploration fronts of the open pit of the Imerys Rio Capim Caulim mine (IRCC), encompassed X-ray diffraction analysis (XRD), differential and gravimetric thermal analysis (DTA-GTA), optical analysis of thin sections, chemical analysis, scanning (SEM) and transmission electron microscopy (TEM), both equipped with an energy dispersive X-ray detector (EDS), porosity and surface specific determinations, cationic exchange capacity (CEC) measurements, UV-visible determination, infrared and Mössbauer spectroscopies, statistical analysis and the Pb-Pb isotopic analysis using single zircon vaporization. Six facies (sand kaolin, soft kaolin, lower transition facies, ferruginous crust, upper transition facies and flint kaolin) are defined and related to different stages of the supergenic process. The transition facies and the ferruginous crust represent relicts of a ferruginization process that led to the formation of a thick ferruginous duricrust on the soft kaolin, which in turn evolved from sandy-clayey sediments of the Ipixuna Formation (sand facies). A subsequent deferruginization event caused the degradation of the duricrust, resulting in the flint kaolin facies. The chemical analyses corroborate to the lateritic processes, characterized by the ferruginization and deferruginization mechanisms that led to the distinction of the different facies. Even if ferruginization and deferruginization mechanisms led to the individualization of different Capim River kaolin facies, the same heavy mineral assembly persists in all facies, evidencing that these minerals originated from the same basal sediments. Provenance studies carried out on the soft and flint faciès allowed to trace the possible sources of sediments that host the ore. The Pb-Pb vaporization method was applied to four predominant morphologic classes of detrital zircons and the ages obtained were compared to the main age intervals of the rocks surrounding the Capim Kaolin District (CKD). Four major plateau ages (2.15, 2.02, 1.87 and 1.51 Ga) were defined for both soft and flint facies, indicating a common source for the kaolin-
Idioma: dc.languagefr-
Direitos: dc.rightsAutorização concedida ao Repositório Institucional da UFOP pelo autor(a), 14/07/2014, com as seguintes condições: disponível sob Licença Creative Commons 3.0, que permite copiar, distribuir e transmitir o trabalho, desde que seja citado o autor e licenciante. Não permite o uso para fins comerciais nem a adaptação desta.-
Palavras-chave: dc.subjectCaulim rio Capim-
Palavras-chave: dc.subjectCaulim geoquímica-
Palavras-chave: dc.subjectCaulim petrologia-
Palavras-chave: dc.subjectCaulim cristalografia-
Título: dc.titleÉtude petrologique et cristallochimique du kaolin de La rivière Capim – Pará, Brésil-
Tipo de arquivo: dc.typelivro digital-
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