The Mazenod Lake region of the southern Great Bear Magmatic Zone (GBMZ) of the Northwest Territories, Canada comprises the north-central portion of the Faber volcano-plutonic belt. Mazenod geology is dominated by rhyodacite to basaltic-andesite ignimbrite sheets with interlayered volcaniclastic sedimentary rocks dominated by fine-grained laminated tuff sequences. Much of the intermediate to mafic nature of volcanic rocks is disguised by low-intensity but pervasive metasomatism. The region is affected by a series of coalescing magmatic-hydrothermal systems that host the Sue-Dianne magnetite-hematite IOCG deposit and several related showings including magnetite, skarn, and IOA styles of alteration ± mineralization. Exposed at surface are dominantly mid to upper levels of these systems, with underlying batholith, pluton and stocks exposed along the periphery, as well as locally within volcanic rocks associated with more intense alteration and mineralization. Widespread alteration includes potassic and sodic metasomatism, and silicification with structurally controlled giant quartz complexes. Localized tourmaline, skarn, magnetite-actinolite, and iron-oxides occur within structural breccias, and where most intense formed the Sue-Dianne Cu-Ag-Au diatreme-like breccia deposit. Magmatism, volcanism, hydrothermal alteration and mineralization formed during a negative tectonic inversion within the Wopmay Orogen. This generated a series of oblique offset rifted basins with continental style arc magmatism and extensional structures unique to GBMZ rifting. All significant hydrothermal centres in the Mazenod region occur along and at the intersections of crustal faults either unique to or put under tension during the GBMZ inversion.