Journal of South American Earth Sciences ( IF 1.704 ) Pub Date : 2020-01-30 , DOI: 10.1016/j.jsames.2020.102510 Alexandre de Oliveira Chaves, Raphael Martins Coelho
Unlike the question brought by Massonne (2020), mica-quartz schist as a source of Córrego do Peixoto granite from Itaguara Sequence is clearly confirmed by geochemical new data. It is a peraluminous (S-type) syn-collisional granite generated by partial melting of the schist as a result of orogen exhumation during Paleoproterozoic continental collision, i.e during the decompression part of clockwise P-T-time path. Preserved in mica-quartz schist, garnet-chloritoid-phengite-kyanite mineral assemblage, typical of high-pressure metapsammopelites, is in equilibrium close to the metamorphic peak suggested by de Oliveira Chaves et al. (2019), according to new pseudosection of this rock. The new discovery of retroeclogite in the IS (Chaves and Porcher, in review) close to schist and granite is sufficient to oppose the comment of Massonne (2020), which sustains that mica-quartz schist from IS has never reached conditions of the eclogite-facies. The geotectonic setting proposed by de Oliveira Chaves et al. (2019) for Itaguara Sequence seems to indicate a reliable Paleoproterozoic accretionary prism in a paleosubduction zone, which can correspond to one of the earliest records of subduction process followed by continental collision in world.