Tectono-Metamorphic Evolution of the Cretaceous Kluane Schist, Southwest Yukon

A groundbreaking study reveals that the Kluane Schist, part of the UNESCO-listed Kluane / Wrangell-St. Elias / Glacier Bay / Tatshenshini-Alsek site, underwent two distinct metamorphic phases rather than a static thermal aureole linked to the Ruby Range batholith intrusion. The research identifies an early greenschist-facies phase followed by a later amphibolite-facies phase, characterized by progressive transposition and a field gradient of 3.0–4.5 kbar at temperatures ranging from 375–750 °C. This Buchan-style metamorphic-deformational evolution, coupled with non-coaxial shear structures, suggests the override of the Yukon-Tanana terrane as the primary driver of metamorphism, with limited heat contribution from the Ruby Range batholith. The study integrates detailed petrography and petrological modeling to challenge previous interpretations and provide new insights into the tectonic evolution of the Northern Canadian Cordillera.

Mckenzie, Will. F., Gibson, H. D., Dyck, B., & Steele-Macinnis, M. (2024). Tectono-Metamorphic Evolution of the Cretaceous Kluane Schist, Southwest Yukon. The Canadian Journal of Mineralogy and Petrology, 62(2), 189–224. https://doi.org/10.3749/2300031