Petrogenesis and tectonic settings of the Neoarchean A-type granitoid complex from the Carajás Province, Amazonian Craton: Constraints from geochemistry, SHRIMP U‒Pb zircon geochronology and Hf–Nd isotopes

Neoarchean granitoids of the Vila Jussara complex are located in the Sapucaia domain in Carajás Province, where they appear as a series of coalescing sigmoidal-shaped plutons along the E‒W direction with high-angle foliations (75-85°) that follow a regional trend. These plutons are formed mainly by seriated biotite–hornblende monzogranite (BHM). Subordinated varieties are biotite–hornblende tonalite (BHT), biotite granite (BG), and hornblende–biotite granite (HBG). Regarding the geochemical features, these granitoids can be distinguished by the Fe* index [FeOt/(FeOt/MgO) ratio]. The BHM presents moderate to high values of this ratio and can be characterized as oxidized and reduced ferroan A-type granites. The BG and HBG are porphyritic granitoids and are transitional between oxidized granites and slightly magnesian granites. In contrast, the BHT has lower and restricted FeOt/(FeOt/MgO) ratios and magnesian characteristics. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb dating results in ages of 2743±11 Ma for the oxidized BHM, the age of 2745±20 Ma for the reduced BHM, age of 2742±14 Ma for the HBG and the age of 2766 ± 9.6 Ma for BHT. The Nd and Hf isotopic data suggest that the magmas of the Vila Jussara suite present a slight crustal contribution with ± contamination [$ε$_Nd(t) values are mostly between −3.62 and +1.55 and $ε$_Hf(t) values are between −4.77 and +1.78] and were derived from rocks of Meso to Paleoarchean age (2.82<T_DM<3.45 Ga). The petrogenetic model that was adopted to ascertain the primary magmas of this suite reveals source rocks that are geochemically similar to Mesoarchean granulites from the Canaã dos Carajás domain. The emplacement of Neoarchean granites occurred by multiple injections of magmas, generating extensive hybridization under a transpressional/transtensional tectonic regime dominated by pure shear and resulting in a syntectonic postcollisional setting of these rocks.