LAUSR

Paleoproterozoic orogenesis within the Archean southeastern Rae craton is related to the initial amalgamation of Laurentia. Characterizing the accompanying tectonic processes during this time has been complicated due to polymetamorphism, which results in the obscuring of the age record of the terranes involved. To improve the knowledge of the tectonic evolution of the South Rae Craton, petrologic and structural analyses are applied in conjunction with in situ trace element chemistry, inclusion barometry, U-Pb monazite and titanite, and Lu-Hf garnet chronology. The data robustly constrain Paleoproterozoic pressure-temperature-time paths of major deformational events along the southeastern Rae craton margin. D1 occurred between 1.94 and 1.93 Ga in the Dodge-Snowbird domain, which included prograde burial of metasedimentary rocks, deposited at 2.2 to 2.0 Ga, and the development of migmatitic layering and east-southeast trending folds (S1, F1). Peak metamorphism is recorded in metasedimentary units at c. 1.93 Ga when rocks reached conditions of 9.0–10.5 kbar and 810–830 °C. Within the Dodge-Snowbird domain, D2 imparted north-northeast trending open folds and associated axial planar cleavage (S2, F2) between 1.93 and 1.90 Ga during east-west compression that appears to have been synchronous with cooling and exhumation. Later D2 deformation, localized within Final version published as: Thiessen, E. J., Gibson, H. D., Regis, D., Pehrsson, S. J., Ashley, K. T., & Smit, M. A. (2020). The distinct metamorphic stages and structural styles of the 1.94–1.86 Ga Snowbird Orogen, Northwest Territories, Canada. Journal of Metamorphic Geology, 38(9), 963–992. https://doi.org/10.1111/jmg.12556.