Abstract
The Capane Antiform is a structure sustained by rocks of the Porongos Metamorphic Suite, which consists of a thick unit of metapelites, with minor quartzites, and lenses of marble and quartz-pebble metaconglomerates, followed by a unit of mafic to felsic metavolcanic rocks, late to post-kinematic granitic intrusions, and tectonically imbricated ultramafic and alkaline gneiss bodies. The metasedimentary rock association is interpreted as having been originally deposited under shallow marine environment, and the volcanics erupted under sub-aqueous conditions. Both rock assemblages are probably Neoproterozoic in age. The textural and structural features of the Capane Antiform rocks indicate predominant mylonitic and non-coaxial deformation. The S 1 e S 2 foliation formed probably during the Brasiliano Cycle by shearing during tangential displacement (D 2 ) and northeastern verging thrusting, parallel to the Dom Feliciano Belt. Zones of higher strain and imbrication are preserved as long and narrow zones of phyllonites and ultramylonites, in their turn gently folded during later stages. The locally preserved S 1 foliation has mineral assemblages of low to medium amphibolite facies, while the dominant S 2 of medium to high greenschist facies. Rocks of low greenschist facies occur in the eastern limb of the antiform and could represent younger sections of the basin, located at the top of the sequence.
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