Journal Article
Geology, Geochemistry and U-Pb Geochronology of Arc-Related Granitoids of the Alta Floresta Gold Province and implications to the Orosirian gold metallogeny of SW Amazon craton, Brazil
Mesquita, MJ; Geraldes, M; Paes de Barros, AJ; Quispe, PC; Matos, JH; Xavier, R; Trevisan, V; Assis, R; Teixeira, R; Moreira, I; Gaidukas, G; ,
SOC GEOLOGY APPLIED MINERAL DEPOSITS-SGA
The Alta Floresta Gold Province (AFGP) is located in the southwestern part of the Amazon craton, between two geochronological provinces Tapajos-Parima (easternmost AFGP) and Rondonia-Juruena. The TapajosParima province is one of the best preserved Paleoproterozoic orogenic belt of South America. In the southwestern part of this orogenic belt several foliated granitoids occur associated with four NW-SE first order shear zones as part of the Peru-Trairdo system, which host several Au-Cu ore zones. The adakitic, high K, Rb and LILE Gringo granitoids (2037 +/- 5.9Ma) are the oldest in the province. The Brag Norte garnet leucogranites (2006 +/- 4.7Ma) are related to the peraluminous crustal leucocratic association, and garnet-kyanite xenoliths indicate high pressure formation. Biotite tonalites, Naiuram granodiorites, micro-granodiorite dikes (2012 +/- 13Ma) and homblendequartz-diorites (1981 +/- 8.1Ma) are geochemically similar, metaluminous, magnesian, medium-K calc-alkaline. Naiuram granodiorites have adakitic composition. Features as: (a) heterogeneous ductile deformation, from high T igneous, to amphibolite facies metamorphic foliation, to mylonitic foliation; (b) medium to high-K calc-alkaline rocks and (c) kyanite-garnet xenoliths in garnet leucogranites may represent a magmatic arc roof present in the Peixoto Azevedo region. The new findings regarding geological framework and adakitic composition of some of the granitoids can contribute to a better understanding of the evolution of the area, Au-Cu fertility of the magma, and geological connections between AFGP and the northern counterpart of the Tapajos Gold Province.
MercierLangevin, P; Dube, B; Bardoux, M; Ross, PS; Dion, C;
14th SGA Biennial Meeting on Mineral Resources to Discover
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