New detrital zircon U-Pb and Hf isotope constraints for the Kluane Schist, southwestern Yukon, Canada, and their implications for Cretaceous Insular terrane accretion

A new study reveals that the Kluane Schist, part of the UNESCO World Heritage Site in southwestern Yukon, Canada, served as a Late Cretaceous depocenter with strong ties to the paleo–western margin of North America. Using detrital zircon U-Pb and Hf isotope analyses from metasedimentary rocks across various structural levels, researchers determined that the Kluane Schist likely formed as the uppermost part of a contractional forearc or arc built upon the Yukon-Tanana terrane. This finding supports models of Insular terrane accretion involving east-dipping subduction beneath a westward-migrating North American continent during the Cretaceous period.

McKenzie, W. F., Gibson, H. D., Colpron, M., Dyck, B., Davies, J. H. F. L., & Perrot, M. G. (2025). New detrital zircon U-Pb and Hf isotope constraints for the Kluane Schist, southwestern Yukon, Canada, and their implications for Cretaceous Insular terrane accretion. Geosphere, 21(6), 962–990. https://doi.org/10.1130/ges02845.1