Syn-collisional peraluminous magmatism in the rio Doce region: Mineralogy, geochemistry and isotopic data for the neoproterozoic Urucum Suite (eastern Minas Gerais State, Brazil) - Laboratoire Magmas et Volcans Accéder directement au contenu
Article Dans Une Revue Special issue Revista Brasileira de Geociencias Année : 2000

Syn-collisional peraluminous magmatism in the rio Doce region: Mineralogy, geochemistry and isotopic data for the neoproterozoic Urucum Suite (eastern Minas Gerais State, Brazil)

Résumé

The Urucum Suite granitoids (Rio Doce region southeastern Brazil) contains four main facies: megafeldspar granites, deformed medium-to-coarse-grained granites, tourmaline, and pegmatitic facies. they intrude both the staurolite-garnet-muscovite-biotite schist of the Sao Tome formation (Rio Doce Group) and the Galileia metaluminous suite (596±4 Ma). Detailed structural studies suggest that the Urucum Suite emplaced during an important dextral strike-slip movement (D1 phase) of the Brasiliano orogeny (650-450 Ma). Modal and chemical mineralogical variations suggest an evolution from the megafeldspar facies to the pegmatitic facies. Whole-rock geochemistry indicates the peraluminous character of the Urucum suite granitoids, the evolution from the megafeldspar facies granites to pegmatite facies granites to pegmatitic facies granites and suggests the syn-collisional character of this suite. U-Pb zircon (582± 2 Ma) and monazite (576-573 ±4 Ma) data indicate that the Urucum Suite emplaced during the Brasiliano orogeny. The peraluminous nature of the Suite and isotopic rich character in the Rb-Sr (87 Sr/86 Sr = 0.7114 to 0.7165) and Sm Nd (eNd(T) = -7.4 and -8.2) systems indicate that it formed by partial melting of older intermediate to felsic crustal sources. Based on early Proterozoic model-ages (2.3 to 1.8 Ga) and on 2.0 ga U-Pb inherited signature, granitoids of the Suite are probably derived from a rocks with a long crustal residence (Transamazonian basement), without extensive mantle contribution
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Dates et versions

hal-01350695 , version 1 (01-08-2016)

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  • HAL Id : hal-01350695 , version 1

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Herminio Arias Nalini, Essaïd Bilal, José Marques Correia-Neves, A. Giret, Jacques Moutte. Syn-collisional peraluminous magmatism in the rio Doce region: Mineralogy, geochemistry and isotopic data for the neoproterozoic Urucum Suite (eastern Minas Gerais State, Brazil). Special issue Revista Brasileira de Geociencias, 2000, 30 (1), pp.120-125. ⟨hal-01350695⟩
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