Stratigraphy
The stratigraphy of the Minnesota portion of the Wabigoon subprovince has been described from limited bedrock outcrops, scattered drill holes and aeromagnetic data (Ojakangas et al. 1977; Ojakangas et al. 1979; Southwick and Ojakangas 1979; Day et al. 1994a; Day et al. 1994b; Jirsa et al. 2011; Hendrickson 2016). The stratigraphy and geochronology of volcanic, intrusive, and sedimentary rocks in the exposed regions of the Wabigoon subprovince in Ontario, Canada were summarized by Czeck and Poulsen (2010), who complied data from Davis et al. (1989) and Fralick and Davis (1999) (Table 2). Overall, mafic and intermediate volcanic and volcaniclastic rocks dominate the stratigraphy. However, drilling data suggests felsic volcanic and volcaniclastic rocks are locally abundant. A generalized stratigraphic diagram of rocks, depositional environments, and deformation events in the Wabigoon, Quetico, and Wawa subprovinces is shown in Fig. 2, and suggest the Wawa and Wabigoon subprovinces host similar Neoarchean island arc-derived volcanic rocks. The Wawa and Wabigoon terranes unconformably bound…show more content… 1977). It is dominantly composed of mafic to intermediate volcanic and volcaniclastic rocks that have been intruded by large granitoid batholiths and mafic intrusions. Iron formation and massive sulfide deposits occur mainly along the southern and northern margins of the BZ where they are interpreted define the limbs of a large NE trending synform. Mafic intrusive rocks in the BZ are often confined to fold axes that likely controlled their emplacement during deformation. Dating of mafic intrusive rocks from the Black River intrusion using Ar-Ar geochronology yielded ages of 2685±11 Ma and 2695±7 Ma, indicating it is older than or contemporaneous with the OI and OIS in the OB (Keatts et al.
