Zircon U-Pb isotopic and geochemical study of metanorites from the chromite-mineralised Bacuri Mafic-Ultramafic Complex: Insights of a Paleoarchean crust in the Amapá Block, Guyana Shield, Brazil

•3.34 Ga igneous zircons reveal the crystallisation age of the layered complex.•3.0-3.3 Ga metamorphic zircons show typical coupled dissolution-precipitation textures.•Paleoarchean crust has been reworked in the Amazonian craton since the Mesoarchean.•Bacuri chromites are the best preserved and oldest orthomagmatic deposit known.