Crustal evolution between 2.0 and 3.5 Ga in the southern Gaviao block (Umburanas-Brumado-Aracatu region), Sao Francisco Craton, Brazil: A 3.5-3.8 Ga photo-crust in the Gaviao block?

The main evolution of the Gavião block in the Umburanas-Brumado-Aracatu region, in the state of Bahia, is defined by several sets of tonalitic-trondhjemitic and granodioritic gneisses emplaced during the Paleoarchean. The juvenile Bernada gneisses are e