Differential uplift across the Coast Plutonic Complex-Northern Stikine Terrane contact, Yukon: Preliminary evidence from apatite fission-track thermochronometry

Six fission-track analyses were conducted on samples taken across a fault in the Takhini Hotsprings area, Yukon. The results indicate that samples taken on the east side of the fault cooled through 100°C at 104.4 ± 11.9 Ma, while the samples taken on the west side of the fault cooled through 100° C at 63.9 ± 8.5 Ma. Differential uplift and faster erosion on the west side of the fault between the mid-Cretaceous and Early Paleocene could account for this difference in cooling history. This fault forms the approximate western edge of the Whitehorse Trough, and is marked by a dramatic change in the isopach of Jurassic and Triassic sedimentary and volcanic rocks which form a thin veneer over rocks of the Coast Plutonic Complex on the west side, and a very thick sedimentary sequence on the east side where basement rocks are not seen. Based on these observations, the fault is inferrred to be a major zone of crustal weakness which could form the boundary betweeen the Northern Stikine Terrane and the Coast Plutonic Complex in southern Yukon. Similar results were obtained in a previous study of samples collected across the Llewellyn Fault Zone, which forms the boundary between the Northern…

Publisher

Government of Yukon

Resources

3

Catalogue metadata updated

2026-08-26