Dating the Itabira iron formation, Quadrilátero Ferrífero of Minas Gerais, Brazil, at 2.65 Ga: Depositional U–Pb age of zircon from a metavolcanic layer

Uranium–Pb dating of zircon from a metavolcanic layer within the Itabira iron formation, or Cauê Itabirite, Quadrilátero Ferrífero of Minas Gerais, Brazil, indicates that its deposition occurred at 2.65 Ga, i.e., considerably earlier than proposed by previous geochronological studies, which suggested deposition between 2.58 Ga (detrital zircon age from the underlying Moeda Formation) and 2.42 Ga (Pb–Pb isochron age from dolomitic rocks of the immediately overlying Gandarela Formation). The new age has major implications for the geology of the Quadrilátero Ferrífero and connects it with the Neoarchaean iron formation of the Carajás mineral province.

► First U–Pb zircon age for a metavolcanic layer within the Itabira iron formation, or Cauê Itabirite, of Minas Gerais, Brazil. ► The new zircon age indicates that the deposition of the Itabira iron formation occurred at 2.65 Ga. ► The new age is considerably older than proposed by previous geochronological studies.