Serra da Queimada Granite, Velho Guilherme Intrusive Suite, Carajás Province: Typology, petrological aspects and metallogenetic affinities

Abstract

The Paleoproterozoic Serra da Queimada Granite, is located in the north of the São Félix do Xingu city, southeastern Amazon Craton. The Serra da Queimada Granite is intrusive in Archean units of the São Félix Group and Paleoproterozoic units of the Iriri Group (Uatumã Supergroup). It consists of leucocratic to hololeucocratic biotite syenogranites, biotite monzogranites and porphyritic syenogranites. The frequent occurrence of spherulitic and granophyric intergrowth suggests that SQG rocks crystallized at shallow crustal levels. The biotite of the monzogranites is magmatic and Fe-rich, with high Alt contents, varying from 3.07 to 3.21. These granites are peraluminous to weakly metaluminous, with FeOt/(FeOt + MgO) ratios between 0.77 and 0.99 and K2O/Na2O between 0.7 and 3.1. They correspond to A-type intraplate and A2 subtype granites, which suggests a crustal source as their origin. They have higher LREE than HREE contents, with marked negative Eu anomalies in biotite syenogranites (Eu/Eu* 0.01–0.03), intermediate in biotite monzogranites (Eu/Eu* 0.25–0.54) and less marked in porphyritic syenogranites (Eu/Eu * 0.39–0.45). BSG have higher Na2O, K2O, Rb, Y, W and Sn and lower TiO2, Fe2O3t, MgO, CaO, Ba and Sr contents compared to other less evolved facies. The Zr saturation geothermometer provided crystallization temperatures between 870 and 754 °C, similar to other Paleoproterozoic anorogenic granites of Carajás Province. Comparative studies with stanniferous granites of the Velho Guilherme Intrusive Suite indicate that biotite syenogranites of the Serra da Queimada Granite have metallogenetic potential for Sn, allowing their inclusion in the geological context of this important granite suite.