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The western Superior Province represents a collage of Mesoarchean continental (3.2–2.8 Ga) and Neoarchean continental, arc and oceanic (2.8–2.66 Ga) crustal fragments. Nd isotope data presented here for 89 felsic volcanic and plutonic rocks have been combined with compiled data to generate a data set of over 240 analyses from the Wabigoon and Winnipeg River subprovinces. These samples, from both oceanic and continental environments have been used as crustal probes, their Nd isotopic character used to investigate the extent of basement terranes, the ancestry of crustal fragments, their interaction with each other, and the degree of sialic crustal reworking. The Wabigoon and Winnipeg River subprovinces include three isotopically distinct terranes: (1) The Winnipeg River terrane comprises the Winnipeg River subprovince, the north-central Wabigoon, and the north-eastern Wabigoon subprovince. This region is dominated by Neoarchean granitoid rocks with Mesoarchean vestiges of Previous workers have suggested that the boundary between the western Wabigoon and Winnipeg River terranes represents a cryptic suture resulting from a collision at circa 2.71 Ga. The boundary between the western Wabigoon and Marmion terranes, although obscured by late intrusions, may be a continuation of this suture zone. The boundary between the Winnipeg River and Marmion terranes in the central Wabigoon is also cryptic. Isotopic data suggest that the Marmion terrane is allochthonous with respect to the Winnipeg River terrane. Common magmatism in these two terranes at 2.93–2.87 Ga suggests that they may have collided during this time. In the eastern Wabigoon subprovince this collision zone is speculated to occur at the Humboldt Bay high strain zone. A complex history of crustal recycling throughout the Mesoarchean and Neoarchean is revealed, which demonstrates the importance of autochthonous development of granite–greenstone terranes in a continental environment. The data also support models of tectonic accretion during the Archean, indicated by the presence of granite–greenstone terranes of allochthonous origin. |
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