The thermochronological record of tectonic and surface process interaction at the Yakutat-North American collision zone in southeast Alaska

A distinct pattern of exhumation emerges in southeast Alaska, primarily driven by tectonic processes rather than climate variations. The study reveals that the southeastern margin was exhumed and eroded long before the late Miocene-Pliocene Yakutat collision, with rapid, deep-seated exhumation localized at the Yakutat plate corner (St. Elias syntaxis), where strike-slip motion transitions to convergence. Exhumation is also notable along the Fairweather fault and in the evolving fold and thrust belt, migrating from northwest to southeast with recent activity near St. Elias. The Wrangellia terrane has experienced minimal exhumation, serving as a backstop for terrane accretion since the Early Cretaceous. Apatite U-Th/He ages provide evidence of recent uplift and erosion in the Wrangell Range due to ongoing Yakutat collision. The study synthesizes new and published thermochronological data, overcoming challenges posed by widespread ice cover, to interpret exhumation patterns influenced by tectonics and surface processes.

Enkelmann, E., Zeitler, P. K., Garver, J. I., Pavlis, T. L., & Hooks, B. P. (2010). The thermochronological record of tectonic and surface process interaction at the Yakutat-North American collision zone in southeast Alaska. American Journal of Science, 310(4), 231–260. https://doi.org/10.2475/04.2010.01