
As características petrográficas e geoquímicas do leucogranito peraluminoso do Complexo de Gouveia (MG), sua relaçãogeológica a migmatitos deste complexo arqueano e a zonas de cisalhamento, bem como sua intensa milonitização, aproximam sua gêneseà dos granitos de ambiente de colisão continental ou da tectônica transcorrente a ela associada. Idades químicas U-Th-Pb em cristaishomogêneos de monazita inclusos em K-feldspato do leucogranito mostram valor médio em torno de 1811 +/- 32 Ma, que marca acristalização do magma leucogranítico derivado da anatexia dos migmatitos. Esta anatexia teria se dado em ambiente hidratado e emcondições de alto grau metamórfico (fácies anfibolito alto) atingidas em função do espessamento crustal e cisalhamentos regionaisrelacionados às fases sin- a tardi-colisionais do evento Transamazônico. Além disso, esta rocha foi submetida ao retrabalhamentoBrasiliano sob fácies xisto-verde, identificado pela cloritização da biotita e da granada e por processos de turmalinização. A monazitaassociada aos corpos tardios de turmalinitos apresenta idade química U-Th-Pb de 634 +/- 20 Ma.Palavras-chave: leucogranito peraluminoso, gouveia, tectônica colisional, transamazônico, brasiliano ABSTRACTThe petrographic and geochemical characteristics of the peraluminous leucogranite of the Gouveia Complex (MG), their association to migmatites of such archean complex and to shear zones and their intense mylonitization approach their genesis to thegranites of continental collision setting or linked transcurrent tectonics. U-Th-Pb chemical ages of 0monazite grains included in K-feldsparof the leucogranite show mean values around 1811 +/- 32 Ma, which reveal its magmatic crystallization from anatexis of the migmatites.The anatexis that generated the leucogranites has been given in hydrated environment and high-grade metamorphic conditions(amphibolite facies) reached during crustal thickening and regional shear related to the syn- to late-collisional phases of theTransamazonian event. However, this rock has been subjected to Brasiliano reworking under green-schist facies, identified by chloritizationof biotite and garnet and by tourmalinization processes. Monazite associated with late tourmalinite bodies has U-Th-Pb chemical age of634 +/- 20 Ma.Keywords: peraluminous leucogranite, gouveia, collisional tectonics, transamazonian, brasiliano.
leucogranito peraluminoso, gouveia, tectônica colisional, transamazônico, brasiliano
leucogranito peraluminoso, gouveia, tectônica colisional, transamazônico, brasiliano
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