Titre:	Nature and evolution of paleoproterozoic Sn and rare metal albitites from Central Brazil : constraints based on textural, geochemical, Ar-Ar, and oxygen isotopes
Auteur(s):	Sirqueira, Ana Rita Félix Moura, Márcia Abrahão Botelho, Nilson Francisquini Kyser, T. Kurt
Assunto::	Albitita Metais não-ferrosos Estanho Isótopos de oxigênio Geologia econômica
Date de publication:	8-sep-2018
Editeur:	MDPI
Référence bibliographique:	SIRQUEIRA, Ana Rita F. et al. Nature and evolution of paleoproterozoic Sn and rare metal albitites from Central Brazil: constraints based on textural, geochemical, Ar-Ar, and oxygen isotopes. Minerals, v. 8, n. 9, 396, 2018. DOI: https://doi.org/10.3390/min8090396. Disponível em: https://www.mdpi.com/2075-163X/8/9/396/htm. Acesso em: 07 maio 2020.
Abstract:	Economic and subeconomic concentrations of Sn, In, rare earth elements (REE), Ta, and Nb are known in Central Brazil, in the Goias Tin Province. The Sn-P enriched albitites studied in this paper occur in sharp contact with peraluminous granites of the Aurumina Suite (2.0–2.17 Ga) and schists of the Archean to Paleoproterozoic Ticunzal Formation, as dikes or lenses from late-stage magma of the peraluminous magmatism, probably in granite cupolas. Geological, petrological, and isotopic studies were conducted. The albitites consist of albite, quartz, cassiterite, apatite, K-feldspar, and muscovite, and have magmatic texture, such as alignment of albite laths, and snowball texture in quartz, apatite, and cassiterite. They are enriched in Na2O, P2O5, Sn, Ta, and Nb (Ta > Nb), and depleted in CaO, K2O, TiO2, MgO, Sr, Ba, Th, and REE. 40Ar/39Ar in muscovite gave a plateau age of 1996.55 ± 13 Ma, interpreted as approaching the crystallization age. Oxygen isotope data in albite-cassiterite pairs resulted in an equilibrium temperature of 653–1016 ◦C and isotopic fluid composition of 8.66–9.72h. They were formed by crystallization of a highly evolved and sodic granitic magma. This study has implications for Central Brazil’s economic potential and offers better understanding of tin behavior in rare, evolved peraluminous granitic magmas.
Licença::	© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
DOI:	https://doi.org/10.3390/min8090396
Collection(s) :	Artigos publicados em periódicos e afins

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