Geochronology and tectonometamorphic history of the Snowbird Lake area, Northwest Territories, Canada: New insights into the architecture and significance of the Snowbird tectonic zone

The results of mapping, geochronology, petrology, and geochemistry of rocks of the Snowbird Lake map sheet (NTS 65D), western Churchill Province, Canada provide new insight into the tectonometamorphic history of the southern Rae Province and significance of the Snowbird tectonic zone, western Churchill Province, Canada. U/Pb TIMS and SHRIMP data document a complex igneous and metamorphic history, with major contrasts between the Rae Province, Chipman domain, and Hearne Province. The Chipman batholith represents the oldest plutonic rock; crystallized at ∼3.4Ga, metamorphosed at 2.85Ga, and intruded at 11kbar by ca. 1.9Ga mafic dykes. Subsequent Neoarchean activity in the Rae Province involved plutonism at ca. 2.735, 2.67–2.66, and 2.55Ga, all events that are documented in other portions of the Rae Province. In contrast, the Hearne Province shows only 2.72–2.66 igneous activity.