The final closure of the ocean around 1.83 Ga, when Hearne, Superior, and Sask cratons merged with the Flin Flon – Glennie Complex, was followed by a period of metamorphism that peaked around 1.82–1.8 Ga. The Manikewan Mobile Belt now covers an area of 600000 sqkm but is overlain by Middle Proterozoic Athabasca sandstone.