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U-Pb dating of the Madeira Suite and structural control of the albite-enriched granite at Pitinga (Amazonia, Brazil): Evolution of the A-type magmatism and implications for the genesis of the Madeira Sn-Ta-Nb (REE, cryolite) world-class deposit
Auteur(s) : Bastos Neto, Artur C. Ferron, T.M.M. Chauvet, Alain Chemale, Farid De Lima, Evandro F. Barbanson, Luc Costa, Clovis F.M.
Auteurs secondaires : Instituto de Geociências ; Universidade Federal do Rio Grande do Sul [Porto Alegre] (UFRGS) Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Instituto de Geociências ; Universidade de Brasilia [Brasília] (UnB) Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO) ; Centre National de la Recherche Scientifique (CNRS) - Université d'Orléans (UO) - Bureau de Recherches Géologiques et Minières (BRGM) (BRGM) - Institut national des sciences de l'Univers (INSU - CNRS) Agência para o Desenvolvimento Tecnológico da Indústria Mineral do Brasil, the Departamento Nacional da Produção Mineral, and Mineração Taboca S.A. for financial support through a FINEP/CTMINERAL Project. They also thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and the CT-MINERAL

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Madeira Sn-Nb-Ta deposit corresponds to the albite-enriched facies of Madeira granite (Madeira Suite) that is part of a NE-SW alignment of three granitic bodies. Structural analyses suggest that the albite-enriched granite emplacement and development of related structures occurred in a different tectonic setting than earlier facies of the granitic bodies in the NE-SW alignment and that the structure was dominated by a N-NE-trending shortening related to a left-lateral motion along a NE-SW corridor within a Riedel shear. Three types of structures (flat-lying, near vertical fractures, and geodes/miaroles) concentrated the last magmatic-related fluid in the albite-enriched granite. U-Pb in situ zircon dating of the albite-enriched granite yielded an age of 1,822 ± 22 Ma. The other granitic plutons of the Madeira Suite, Água Boa granite (topaz-granite facies), and Europa per-alkaline granite formed at 1,825 ± 14 Ma, 1,831± 11 Ma, and 1,839 ± 10 Ma, respectively. The granite bodies of the Madeira Suite occur in an area occupied by a cauldron complex composed of volcanic sequences (Iricoumé Group) and associated A-type granites (Mapuera Suite), and their formation was controlled by the reactivation of the cauldron structures and the pre-existing structures. The gap between the cauldron complex and the Madeira Suite is no greater than 35 Ma. The geological evolution was reanalyzed from the perspective of an entire extensional environment where three successive episodes of A-type magmatism and basin formation (Urupi Formation) occurred. The data and interpretations of this work imply crucial constraints on the petrologic models proposed for the albite-enriched granite and, consequently, on the genesis of the Madeira deposit
ISSN: 0301-9268

insu-00939888
https://hal-insu.archives-ouvertes.fr/insu-00939888
https://hal-insu.archives-ouvertes.fr/insu-00939888/document
https://hal-insu.archives-ouvertes.fr/insu-00939888/file/BastosNeto-PrecambrianResearch-2014.pdf
DOI : 10.1016/j.precamres.2013.12.021

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