This basal unit of the Povungnituk Group was originally described by Taylor (1982) and attributed by Moorhead (1989) to the Lamarche Subgroup (Lamothe et al., 1984), which was abandoned in this compilation. Despite its limited thickness and irregular distribution, the importance of this unit for the palinspastic reconstruction of the orogen was considered sufficient to elevate it to the rank of formation.

The Korak Formation is an allochthonous sedimentary unit located at the base of the Southern Domain. It forms the basal unit of the Povungnituk Group and consists of metre-thick lenticular beds of polymictic conglomerate and arkosic sandstone unconformably (angular discordance) lying on Archean bedrock (Taylor, 1982; Moorhead, 1989, 1996a, b; St-Onge and Lucas, 1993). North of Allemand Lake, sandstone overlies massive muscovite schist that Moorhead (1989) interpreted as paleoregolith. Bedrock underlying the Korak Formation has no visible Proterozoic deformation and, in some cases, retains an N-S foliation typical of the Archean craton (Moorhead, 1996a, b). Normal faults cutting both bedrock and its parautochthonous cover were observed locally (Moorhead, 1996b). The summital portion of the formation shows intense deformation associated with basal decollement of overlying allochthonous units (St-Onge et al., 1988; Lucas, 1989). Conglomerate pebbles are composed of granodiorite and hyaline quartz.