Provenance of metasedimentary rocks of the Araxá group in the central Brasília belt

The Araxá Group in the region of Morrinhos – Marcelândia is constituted of pelitic to psammo-pelitic rocks metamorphosed in amphibolite facies, kyanite/ staurolite stability field. Chemical composition and La/Lu, La/Sc, Th/Sc, La/Co, Th/Co and Cr/Th rates of these rocks suggest that the main source of these sediments were felsic rocks from magmatic arcs. T DMNd model ages (1.21 and 1.76 Ga) and U/Pb ages (< 1.0 Ga and > 1.0 Ga in detrital zircon) suggest contribution of a neoproterozoic (predominant) source and contributions of an older paleo-mesoproterozoic source. The congruence of these geochronological data with geochemical signatures of this geological unity allow to state that a significant part of the Araxá Group in this region had rocks from neoproterozoic magmatic arcs as source, implying that these were deposited in fore arc basins.