Crustal growth through successive arc magmatism: reconnaissance U-PbSHRIMP data from the northeastern Superior Province, Canada

North of the La Grande subprovince in northern Quebec, the Superior Province is dominated by plutonic rocks of the Bienville subprovince and Minto block, which have been further subdivided into domains on the basis of reconnaissance geological mapping and geochronology, and projected along strike using aeromagnetic anomalies. To test the validity of the extrapolations, U-Pb ages were obtained through SHRIMP analyses of zircon from 18 small archival samples selected from a suite of similar to 2000 specimens collected during a helicopter reconnaissance survey conducted in the 1960s. The results reveal a history of successive are magmatism between 3.07 and 2.70 Ga, followed by metamorphism, emplacement of crustally-derived granites (2.702-2.685 Ga) and late hydrothermal events (ca. 2.65 Ca). In the northeastern Minto block, the Douglas Harbour domain, previously extrapolated from dated localities to the northeast, is substantiated through an age of 2.87 Ga. The older tonalitic crust is punctured by 2.734-2.725 Ga granodioritic plutons of the Leaf River suite that locally carry 3.01 Ga inherited zircon. The northern Utsailk domain is made up of pyroxene and hornblende-bearing Leaf River plutons with consistent 2.725-2.723 Ga ages and local inheritance of 2.82 and 2.77 Ga. However, the southern extension of Utsalik domain contains pyroxene-bearing granodiorites both older (2.762 Ga) and younger (2.692 Ga) than the Leaf River suite. A tonalitic rock from the southern Goudalie domain with an age of 2.833 Ga supports a linkage to 2.84-2.83 Ca units of the Qalluviartuuq domain along strike to the north. Tikkerutuk domain represents a north-trending, 50-km wide calc-alkaline magmatic are with ages between 2.71 and 2.70 Ga, that extends southward into the Bienville subprovince on the basis of aeromagnetic anomalies and geochronology. Zircon inheritance ages indicate that the Tikkerutuk are was built upon antecedent arcs of 2.84, 2.77 and 2.725 Ga. The Inukjuak domain in the west consists mainly of granite, dated in one locality at 2.72 Ga. (C) 2001 Elsevier Science B.V. All rights reserved.