The CS-III magnetometer, sampling at 1,000 Hz has in turn broadly defined two major magnetic domains separated by NE-SW striking Black Bay Fault (Figure 3) and roughly corresponding to Paleoproterozoic crystalline basement rocks of the Beaverlodge and Zemlak Domains of the Rae sub-province. The Zemlak Domain comprises foliated to gneissic granitoid rocks of inferred Archean age, as well as locally graphitic psammopelitic to pelitic gneisses and migmatites, and widespread leucogranites of inferred early Proterozoic and/or late Archean age. The rock include: 1) variably magnetic orthogneisses, 2) pelitic gneissic to migmatites and derived diatexites, 3) locally garnetiferous leucogranites, and 4) rocks that are too altered and mylonitized to classify. Тhe Beaverlodge Domain hosts northern margin of the Athabasca Basin, which trends erratically along the southernmost point of the Crackingstone Peninsula. This unconformable contact displays windows of the Murmac Bay Group quartzite/quartz-feldspathic gneisses overlain by 1.71 to 1.50 Ga Athabasca Supergroup sandstones, breccias, and basal conglomerates, which outcrop intermittently and are occasionally stratigraphically reversed. Read More