Circum-Superior Belt northwestern Superior craton margin intrude an older, 2,090 to 2,070 million-year-old dike swarm. The Ospwagan Group is younger than and the 1,864 million-year-old Winnipegosis komatiite belt lies to the southwest. Numerous tectonic settings have been suggested for triggering magmatism in the Fox River Belt, including a marginal basin rifting event. At the southern portion of the Circum-Superior Belt, a group of fragmental sediments composed of iron formation was formed during a period of magmatic activity in the Marquette Range Supergroup. Included in the Marquette Range Supergroup is the Hemlock Formation, a bimodal volcanic group that is estimated to have an
Circum-Superior Belt pounds of nickel. At least two nickel deposits are in progress by Vale Inco at the Thompson and Birchtree mines. At least 70 million pounds of nickel has been mined since 2005. At the city of Thompson, nickel of the Thompson Belt is smelted and refined in facilities. This smelting and refining process contributes to about one-third of the total nickel output in Canada. In the Cape Smith Belt of northern Quebec, the Raglan Mine lies in copper-nickel deposits of the ultramafic Katiniq Suite sills. The Katiniq Suite sills are also within an area that is presently explored for nickel,