Fortes P. de Tarso Ferro de Oliveira auteur aut IRD Giuliani Gaston auteur aut IRD Féraud G. auteur aut IRD text journalArticle eng text/pdf reformatted digital access K-Ar and 40Ar/39Ar geochronological studies were performed on selected minerals from the Minna III gold deposit, Crixas greenstone belt, state of Goias, central Brazil. They include amphibole and biotite from amphibole schists ; biotite from quartz-chlorite-carbonate-muscovite schists ; chloritoid, muscovite, and paragonite from muscovite schists ; and biotite from biotite-marbles. Analyses yielded ages between 750 and 500 Ma, indicating that the Brasiliano orogenic event affected rocks of the Archean greenstone belt. It is proposed that the gold mineralization, closely related to a post-metamorphic peak hydrothermal alteration and spatially associated with muscovite schists, is 505 +/- 10 Ma, whereas older ages may indicate an excess of argon. (Résumé d'auteur) specialized MINERAI METALLIQUE OR MINE GEOCHRONOLOGIE DATATION ISOTOPE RADIOACTIF MINERALISATION METAMORPHISME SCHISTE AMPHIBOLE BRESIL GOIAS 064GEOCHI 39 449-460 1997 0020-6814 https://www.documentation.ird.fr/hor/fdi:010019277 0020-6814 [F B010019277] https://www.documentation.ird.fr/hor/fdi:010019277 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_51-52/010019277.pdf IRD - Base Horizon / Pleins textes 1999-10-11 2018-06-15 fdi:010019277 fre