Geology and geochemistry of intrusive suite serra da providência granite rocks of Juína Region, Northwest of Mato Grosso State

Abstract

The granitic rocks associated to the Serra da Providência Intrusive Suite occur in Juína city vicinity, in the extreme northwest of Mato Grosso State, and are located southwest of the Amazon Craton, in the Rondônia-Juruena Province, Roosevelt-Aripuanã Domain. There are intrusive rocks in Roosevelt Group meta volcanic-sedimentary sequence lithotypes, and assemble small igneous bodies, besides a main batholith of elongated form in E-W general direction, with remarkable rapakivi textured features, here denominated Juína Granite Batholith. The porphyritic rosy to light ash color syeno- to monzogranites predominate, presenting rapakivi potassium feldspar phenocrysts of up to 5 cm, inserted in dark thick granulation and rich in biotite and rare hornblend matrix, which allows the identification of leuco- to melagranites varieties. Gray and pink inequigranular rocks of medium to coarse granulation and coarse equigranular, besides aplitic and pegmatoid features are identified. It is observed a strong deformation, imposing diverse lithological varieties, mylonitic banded and porphyroclastics textures. These are ferrous granitoids, A type, metaluminous to peraluminous, calcium-alkaline from the high potassium to shoshonite series, post-collisional to anorogenic and to arc tectonic in an intraplate environment.