Circum-Superior Belt sills. Geochemical indications suggest that the overlying Flaherty volcanics might also have relationships with the Povungnituk volcano-sedimentary group in the Cape Smith Belt, indicating the Flaherty volcanics might be 2,040 to 1,960 million years old. Sills on the Belcher and Snowy islands in Hudson Bay are dated to 1,870 million years old, indicating the 1,880 million-year-old magmatism also exists in this section of the Circum–Superior large igneous province. The Fox River Belt in northern Manitoba is composed of sediments, volcanics and sills. Fox River Belt sills and Molsen dikes are 1,883 million years old, but the Molsen dikes at the
Circum-Superior Belt Circum-Superior Belt The Circum-Superior Belt is a widespread Paleoproterozoic large igneous province in the Canadian Shield of Northern, Western and Eastern Canada. It extends more than from northeastern Manitoba through northwestern Ontario, southern Nunavut to northern Quebec. Igneous rocks of the Circum-Superior Belt are mafic-ultramafic in composition, deposited in the Labrador Trough near Ungava Bay, the Cape Smith Belt near the southern shore of Hudson Strait and along the eastern shore of Hudson Bay in its northern portion; the Thompson and Fox River belts in the northwest and the Marquette Range Supergroup in its southern portion. A number of magmatic