3.30 Ga high-silica intraplate volcanic–plutonic system of the Gavião Block, São Francisco Craton, Brazil: Evidence of an intracontinental rift following the creation of insulating continental crust

High-silica rhyolites having U–Pb zircon ages of 3303 ± 11 Ma occur along the eastern border of the Gavião Block (Brazil) associated with the Contendas-Mirante and Mundo Novo supracrustal belts. Unlike many Archean greenstone sequences, they are not interlayered with mafic to intermediate units. Instead, they belong to an inter-related plutonic–volcanic system, together with granitic massifs having similar zircon crystallization ages of ca. 3293...