Petrologia, deforma??o e geocronologia U-Pb (SHRIMP) do Granito Coimbra – Bloco Rio Apa na regi?o de Corumbá, Brasil

摘要

Coimbra Granite represents part of the region of Corumbá’s (MS) basement. This body is composed by pink porphyritic?facies, grey medium-to-thick facies and pink thin facies. A deformation phase of compressive character (F1) generated an?expressive foliation N10-20E in this body, with formation of parallel shear zones. Posterior to neoproterozoic deposition?layers, a brittle deformation phase (F2) generated faults and fractures. The studied granite presents intermediate-to-acid?composition, generated in a magmatic arc environment from metaluminous-to-peraluminous calc-alkaline magmatism of?magnesian nature, which is litochemicaly characterized as tonalites, granodiorites, granites and alkali-granites. U-Pb/SHRIMP?zircon crystallization age is 1859 ± 4 Ma and isotopic data Sm/Nd in whole rock indicate ε Nd (1,86Ga) of -1,35 and T DM model age of 2,27 Ga, which suggests the participation of rhyacian source in the origin of magma. Petrographic, lithochemical,?geochronological and isotopic similarities among Coimbra Granite, Taquaral Granite and the intrusions sheltered by?Alumiador Intrusive Suite of the Rio Apa Block suggest that the Coimbra Granite elongs to the same magmatism of the?referred suite, and consequently to the Amoguijá Magmatic Arc of Rio Apa Block.