The granitoids of sanukitoid affinity of the Ourilândia do Norte area, located near the Rio Maria-Carajás domain boundary, are associated with Rio Maria sanukitoid suite from the Mesoarchean age. In this area dioritic, quartz-monzodioritic, tonalitic and granodioritic rocks with variable proportions of amphibole and biotite were described. Contrary to what is observed in the sanukitoid rocks of the Rio Maria area, those of Ourilândia do Norte are constantly affected by deformational processes, relating to the installation of the Itacaiúnas Shear Zones. They exhibit pervasive foliation and microstructures developed under three dynamic recrystallization regimes: (1) Bulging recrystallization (300-400°C); (2) Subgrain rotation recrystallization (<500°C); (3) Grain boundary migration recrystallization (<600°C). Granitoids with sanukitoid affinities are magnesian and metaluminous and belong to medium to high potassium calc-alkaline series. They display non-collinear trends from (quartz) diorite toward granodiorite and exhibit a negative correlation for compatible elements (CaO, Fe2O3 t, MgO, TiO2, Zr, Ni, Cr and #Mg) and inverse behavior for incompatible ones (Ba, Sr), as well as Rb/Sr and Sr/Ba ratios. Moreover, they show amphibole, clinopyroxene and subordinate biotite and plagioclase fractionation. The clinopyroxene-bearing monzogranite shows trends parallel to those of sanukitoids and has a lower Sr/Ba ratio and #Mg content, due to its ferrous character, and probably does not belong to the sanukitoid series. The REE pattern of granodiorite shows a slight or absent Eu anomaly (Eu/Eu*=0.76-0.97) and moderate (La/Yb)N ratio, indicating garnet, amphibole or pyroxene fractionation. Tonalites are less depleted in HREE and have little Eu anomaly (Eu/Eu*=~0.95). Enclaves, (quartz) diorite and quartzmonzodiorite exhibit negative to positive Eu anomalies (Eu/Eu*=0.56-1.71) and a low (La/Yb)N ratio, whose horizontal pattern is similar to that of intermediate rocks from the Rio Maria area. Clinopyroxene-bearing monzogranite shows affinities for the tholeiitic series, following slightly different trends from granitoids, with a negative Eu anomaly (Eu/Eu*= 0.63-0.98) and (La/Yb)N slightly fractionated ratios. Negative Nb-Ta-Ti anomalies, associated with high (La/Yb)N and Y/Nb ratios suggest that these rocks were generated in a subduction zone from a depleted source mantle which was contaminated by fluids or melt. Analysis of the metassomatic agent nature revealed that less evolved rocks were contaminated by fluids, while granodiorites and related rocks were contaminated by melt, whose composition is similar to that of tonalite-trondhjemite-granodiorite (TTG). Enclaves, (quartz) diorite and clinopyroxene-bearing monzogranite were produced by relatively low pressures (La/Yb<1.0 GPa) and depths (<33.6 Km), with little or no residual garnet, while the other granitoids could ix have been generated under superior geothermal conditions (La/Yb=1.0-1.5 GPa; 33.6-50.5 Km) with variable proportions of residual garnet. Furthermore, these granitoids started to crystallize at depths between 30.3 and 20.2 Km and ended between 10.1 and 6.7 Km. Ourilândia do Norte sanukitoid rocks and the other analoguous intrusions of the Carajás Province show geochemical and petrogenetic affinities with high-SiO2 adakites and low-TiO2 sanukitoids. They may have originated through a one-stage process, by direct hybridization between the mantle and TTG-melt. Nevertheless, the modeling performed on Rio Maria and Karelian sanukitoids indicates that they were produced by a two-stage process, from meltmetasomatized peridotite remelting.
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