Geological, petrographic and geochemical characterization of the Sararé Massif in the Southwest of the Amazonic Craton.

Abstract

The Sararé Massif is an intrusion into in the Jauru Domain, located in the southwest of Mato Grosso. The regional NW-SE transcurrent structures controlled the elongated shape, and late brittle deformation showing NE-SW fractures and faults affected the massif. The intrusion is constituted by three major petrographic facies (biotitemonzogranite, muscovite-monzogranite and hololeucocratic monzogranite), with transitional contacts. These rocks present monzogranitic composition, all of them are red-colored, leucocratic, isotropic, equi to inequigranular, and locally porphiritic, with medium grain size. They are S-type rocks, peraluminous, with high-K, and chemically restricted in relation to SiO2 (about 75% wt). The study of REE indicates three asymmetrical and similar distribution patterns, pointing to three distinctive facies, but with different values and reduction of REE for the final phase with depletion of Eu. The massif represents differentiated intrusion of the melting material from the upper crust in continental collision environment, related to the end of the Sunsás-Aguapeí Event