Ore Deposits Related to the Keweenawan Rift

The geochemistry, genesis, and geotectonic setting of Proterozoic mafic dyke swarms in southern and central Sweden

“…The Keweenawanaged, rift-related metallogenesis in the Lake Superior area is well-known. Here, disseminated CuNi, Co-hlo deposits, native-Ag and Cu, chalcocite veins and Nb are common elements (Norman 1978). Similar Cu-mineralizations have been recovered in the Coppermine River and the grabenfaulted Salt Lake areas in Canada.…”

Revisions of stratigraphic nomenclature within the Keweenawan Supergroup of Northern Michigan. Geochemistry, petrography, and volcanology of rhyolites of the Portage Lake volcanics, Keweenaw Peninsula, Michigan

“…Although the hotspot-related Midcontinent rift system hosts some exceptional mineral deposits, including the world's largest native copper deposits (see, for example, Butler and Burbank, 1929;White, 1968) and very large copper-nickel deposits (Nicholson and others, in press), most MRSrelated mineral deposits are associated with mafic and sedimentary rift rocks, not with intermediate to felsic rocks. The only exception is the copper-molybdenum deposit in rhyolite-hosted breccia pipes, believed to be Keweenawan in age, in the Tribag area of Ontario (Blecha, 1965;Armbrust, 1969;Norman, 1978;Norman and Sawkins, 1985;Richards and Spooner, 1989).…”