Syn-Collisional Peraluminous Magmatism in the Rio Doce Region: Mineralogy, Geochemistry and Isotopic Data of the Neoproterozoic Urucum Suite (Eastern Minas Gerais State, Brazil)

Abstract

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 São Tomé Formation (Rio Doce Group) and the Galiléia metaluminous suite (596 ±4 Ma). Detailed structural studies suggest that the Urucum Suite emplaced during an important dextral strike-slip movement (D 1 phase) of the Brasiliano orogeny (650-450Ma). 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 pegmatitic facies granites and suggests the syn-collisional character of this suite. U-Pb zircon (582 ± 2 Ma) and monazite (576-573 ± 4Ma) 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.

The Tectonic interaction between the Paramirim Aulacogen and the Araçuaí Belt, São Francisco craton region, Eastern Brazil

“…The results of our structural analysis presented in the previous sections, along with data obtained from the literature, can be summarized as follows: Based on these results and on the geochronological data provided Celino et al (2000), Nalini Jr et al (2000, Noce et al (2000), Pedrosa Soares and Wiedemann Leonardos (2000), Pedrosa Soares et al (1992), Tack et al (2001 and Silva et al (2002), we propose an evolutionary model for the development of the Paramirim aulacogen and its tectonic interaction with the Araçuaí belt during the inversion processes. This model comprises the following stages illustrated by the cartoon shown on Figure 12:…”

Late Neoproterozoic-Cambrian granitic magmatism in the Araçuaí orogen (Brazil), the Eastern Brazilian Pegmatite Province and related mineral resources

“…The following synthesis on G1 supersuite is based on data from Söllner et al (1991); Nalini-Junior et al (2000a, 2008; Bilal et al (2000); Noce et al (2000Noce et al ( , 2006; Pedrosa-Soares & WiedemannLeonardos (2000); Pedrosa-Soares et al (2001a, 2008; Pinto et al (2001) ; Whittington et al (2001); Silva et al (2002Silva et al ( , 2005Silva et al ( , 2007; De ; Martins et al (2004); Vauchez et al (2007); Vieira (2007); Gomez (2008); Novo (2009) ;Petitgirard et al (2009), and references therein. This supersuite includes suites, batholiths and stocks locally named Brasilândia, Derribadinha, Divino, Estrela-Muniz Freire, Galiléia, Guarataia, Manhuaçu, Mascarenhas-Baixo Guandu, Muriaé, São Vitor, Teófilo Otoni, Valentim and others.…”

Age, provenance and tectonic setting of the high-grade Jequitinhonha Complex, Araçuaí Orogen, eastern Brazil

“…This is the case of the Rio Doce Group (Nalini et al 2000, Pedrosa-Soares et al 2001, 2011b, Martins et al 2004, Vieira 2007, Novo 2013) and the Nova Venécia Complex, composed of peraluminous paragneiss with intercalations of calcsilicate rocks , Gradim et al 2014. Both of those units bear an important detrital zircon U-Pb age peak at ca.…”

“…585 Ma in the core of the basin, building a pre-collisional magmatic arc represented by the G1 supersuite and volcano-sedimentary successions of the Rio Doce Group (Fig. 2) (Nalini et al 2000, Pedrosa-Soares et al 2001, 2011aMartins et al 2004, Vieira 2007. The Nova Venécia Complex, composed of peraluminous paragneiss with intercalations of calcsilicate rocks, represents pre-collisional deposition in the back-arc basin related to the G1 supersuite , Gradim et al 2014.…”