Pre-2.8 Ga crust in the Opatica gneiss belt:A potential source of detrital zircons in the Abitibi and Pontiac subprovinces, Superior Province, Canada

Ages of detrital zircons in post-2.7 Ga metasedimentary rocks of the southern Abitibi and northern Pontiac subprovinces require that pre-2.8 Ga crust was exposed during or following deformation of the 2.70 and 2.68 Ga, and the belt forms a high-grade crystalline core to a south-vergent mountain belt along the northern margin of the Abitibi subprovince. Erosion of the Opatica and northern Abitibi during thrusting would shed detritus southward in advance of a south-vergent thrust system. The Lac Rodayer complex may be the enigmatic source of ∼2.8 Ga detrital zircons within turbidites of the southern Abitibi and northern Pontiac subprovinces.