The Carajás Province (CP) represents the largest preserved Archaean core of the Amazonian Craton with worldwide correspondents. Thus the Tucumã área, located in the northwest portion of the Rio Maria Domain (RMD) near the tectonic border with the Carajás Domain (CD), is marked by the occurrence of mesoarchean age granitoids. This study deals with the discrimination and characterization of this region granitoids which according to the regional studies is dominated by the Rio Maria suíte, by Xingu Complex rocks and metamafics of the greenstone belts sequences. However since data obtained in this work with geological mapping in detailed scale showed that the geological framework of Tucumã is much more diverse and complex. So that contrary to previous studies the most expressive unit in the region are high-K leucomonzogranites rocks that occur as a large plúton. Associated to this pluton small enclaves of granitoids of various compositions are presente in the form of lenses, controlled by NE-SW and E-W anastomosed shear zones. These bodies distinction led to the recognition of five groups: i) high-K Leucomonzogranite; ii) high-HFSE Granites subdivided into medium- and high-Ba; iii) porphyry médium-K Granodiorite; iv) high-Mg Granodiorite; and v) high-Na Tonalite. The granitoids have affinity with the calc-alkaline series, other than high-Na tonalites which follow the trondhjemitic trend with TTG affinities. The latter refers to magnesian granitoids Na2O rich (low K2O/Na2O ratio) which also differ from the others due to the N-S structural pattern often found in greenstone belt sequence, associated with an older tectonic in the region. The moderately fractionated REE patterns (medium La/Yb and Sr/Y ratios) and absence or small negative Eu anomaly typical of TTGs, are features similar to those of médium La/Yb ratio Mogno trondhjemite. With regard to the calc-alkaline units the porphyry médium-K granodiorites differ from the others by the magnesian feature and higher enrichment in Na2O (médium K2O/Na2O ratio) which set forth a resemblance to the TTG suites. However the médium-K granodiorites have higher levels of Ba, K and Th than TTG composition rocks, indicating strong similarities to the so-called transitional or enriched TTG suites. The small differences in the geochemical pattern of these two units are related to changes in the source, where the TTGs (high-Na tonalites) would be the product of the partial melting of a hydrated mafic source (metabasalts), on the other hand the transitional TTGs (porphyry médium-K granodiorite) would originate from melts of a heterogeneous crust with intercalation of enriched basalts and felsic layers. The high-Mg granodiorites occurs in a restricted way in Tucumã identified only in two outcrops. They are distinctly more enriched in Sr and mantle elements (Mg, Cr and Ni) and impoverished in HREE regarding the other granitoids. These features show strong affinities with the sanukitoides suites (Rio Maria Granodiorite) linked to the partial deep melting of the metassomatized mantle. The high-HFSE Granites (medium- and high-Ba) share geochemical characteristics with both the sanukitoide suite and the high-K leucogranites suíte similar to Hybrid granites like the Closepet-type. These suites represent different degrees of interaction processes (mingling or mixing), in the middle crust between crustal melts (tonalites/metassediments) and enriched mantle differentiated melts. Whilst the high-K leucomonzogranites represent the most evolved rocks in the region, where its enrichment in LILEs (Ba, K and Rb) and presence of the negative Eu anomaly indicates crustal reworking processes of an ancient felsic (tonalitic) crust at intermediate crustal levels. This unit has affinities with tha Xinguara and Mata Surrão granites. Regarding the deformation pattern, the rocks with the highest degree of deformation are the high-Na tonalities, in the other units this pattern is only identified in the portions where the shear zones are located. The observed textures (mantle-core and microcracks textures) suggest the operation of deformation processes during the magma crystallization typical of sintectonic granitoids under high temperature conditions (>500ºC). Less deformed granitoids present evidence of dynamic recrystallization at temperatures below 400°C. Thus, in RMD two phases of magmatism are identified, being the first one (2,98-2,92 Ga) related to a subduction setting under an oceanic plateau or a thickened mafic crust with melting at different crustal levels (crust root and slab), and mantle metassomatization by TTG melts and fluids. The second phase (~2.87 Ga) starts from thermal events (slab breakoff, delamination or mantle plumes) that results in partial meltilng of the metassomatized mantle with production of sanukitoide magmas and hybrid granites. This results in changes of the crustal root thickness that lead to substancial temperature variations sufficient to generate partial melting in and beneath the crust associated to generation of high-K granites.
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