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 remain undated, indicating the existence of magmatic rocks with the same age as those of the Circum-Superior Belt is probable. It contains two large copper-nickel mining districts; the nickel-bearing Thompson Belt at the northwestern portion of the Superior craton and the Cape Smith Belt at the northern portion of the Circum-Superior Belt. The Circum-Superior Belt was formed 1,884 to 1,864 million years ago when the Superior craton was surrounded by mountain building processes, including the Trans-Hudson, New Quebec and Penokean orogenies. The major Trans-Hudson orogeny had its appearance when the Superior craton collided with the Rae-Hearne craton 1,900 to 1,800