In southernmost Nunavut, basal clastic rocks and overlying volcanic and carbonate units are well exposed on the Belcher Islands in southern Hudson Bay. These rocks record the subsidence and rifting of the western margin of the Superior craton. Paleoproterozoic deformation, and a strong, attendant thermal overprint, are recognized throughout the map area. Baffin Island . Some of the oldest rocks in Nunavut are exposed in parts of northern Baffin Island.
Kimberlite pipes occur in northwestern part of the island.
On southern Baffin Island, the Lake Harbour Group contains ultramafic sills that have recently been investigated for their nickel potential. Central Baffin Island was once part of an ancient Archean continent. Zinc, silver and lead ore of the Nanisivik Mine is hosted in carbonate strata of the Bylot Supergroup. Numerous small showings of uranium mineralization are known at the base of the the Fury and Hecla Group. These rocks were gently folded and faulted prior to deposition of the overlying Phanerozoic strata.