Analysis: The Wabigoon Subprovince

Geologic Setting
The Wabigoon Subprovince is part of the Superior Province, an Archean age craton composed of E-NE trending granite-greenstone and metasedimentary terranes that span from western MN to northern Quebec. In Canada, the Neoarchean Wabigoon subprovince hosts numerous precious and base metal deposits, including the Sturgeon Lake VMS deposits and Rainy River and Hammond Reef gold deposits. Historically considered moderately to weakly prospective for hosting VMS deposits due to inferred shallow marine conditions and relatively low temperature felsic volcanic rocks (Lesher et al., 1986; Gaboury and Pearson, 2008), the observation that many Wabigoon- hosted gold deposits may exhibit characteristics of epithermal deposits (e.g. Rainy
It is subdivided, from north to south, into the Wabigoon, Quetico, Wawa, and Minnesota River Valley (MRV) subprovinces (Figure 2, Jirsa et al., 2011). The Wabigoon subprovince is composed of greenschist facies mafic volcanic and volcaniclastic rocks intruded by granitoid batholiths. Algoma-type iron formation and small mafic intrusions are also common in this terrane. Amphibolite to greenschist facies rocks comprise the majority of the Quetico subprovince. In Minnesota, it occurs as a westward thinning belt of relatively homogenous metasediments and interstratified migmatites. The Wawa subprovince is composed of greenschist facies mafic and felsic volcanic rocks, granitoid batholiths and subsidiary Algoma-type iron formation. The MRV is the oldest of the terranes, and is characterized by granulite facies gneissic domes (Jirsa et al.,
The stratigraphy of the Wabigoon subprovince in Minnesota has been described from sparse bedrock exposure, 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). Rock in the better exposed portions of the Wabigoon subprovince in neighboring Ontario have been summarized by Czeck and Poulsen (2010), with description of the main lithological units taken from Davis et al. (1989) and Fralick and Davis (1999) (Table 1).
Due to lack of outcrop, the Wabigoon subprovince in MN is currently interpreted to host a simple suite of volcanic, plutonic, and sedimentary rocks. Mafic to intermediate volcanic rocks are most common, with drilling data suggesting subordinate felsic volcanic and volcaniclastic rocks are locally prevalent. Magnetic data indicate the subprovince hosts thick layers of iron-rich strata. Drilling data and previous studies (Southwick et al., 1990) suggest these iron-rich strata are Algoma-type iron