This unit was previously named “Napeu Kainut Quartz Monzonite” by Miller et al. (1997). Following field checks conducted in the summer of 2016, Charette et al. (2019) renamed it the Napeu Kainut Suite to represent the lithological diversity and to comply with the North American Stratigraphic Code (NACSN, 2005). This suite groups massive quartz monzonite and granite units described by Bélanger (1984) in the Brisson Lake area, corresponding to the author’s subunits 10a and 10b respectively.

The Napeu Kainut Suite consists of two informal units: quartz mangerite and quartz monzonite (mPnak1), and granite (mPnak2). At the edge of the intrusion, the rock is locally altered and deformed, which could imply intrusion in a solidified host.

Unit mPnak1 consists of quartz monzonite, locally containing hypersthene, pinkish to reddish grey with a pinkish to brownish alteration patina. The rock is massive, homogeneous and medium to coarse grained with K-feldspar phenocrystals (1-3 cm). Weathering is often so severe that the rock breaks down over a thickness of several metres. Ferromagnesian minerals (3-15%) are disseminated or in small clusters and include mostly brown biotite, and locally hornblende, hypersthene and clinopyroxene. K-feldspar phenocrystals have a perthitic texture and contain some rounded quartz inclusions. Quartz also forms even-grained zones between phenocrystals. Allanite, opaque minerals, epidote and chlorite are accessory minerals. Alteration is marked in places by plagioclase sericitization, biotite chloritization and the occurrence of hematite, carbonate, chlorite and epidote in the matrix.