New U-Pb ages from the Teslin area, southern Yukon, and their bearing on terrane evolution in the northern Cordillera

Abstract

Highlights from a regional U-Pb, K-Ar, and 40Ar/39Ar dating program in southern Yukon include ages from metaplutonic rocks of Yukon Tanana terrane (350-340 Ma), from peridotite of the Cache Creek terrane (ca. 245 Ma), from conglomerate clasts of the Laberge Group of Stikine terrane (229-204 Ma), and from detrital zircons (1.76-3.29 Ga) from Cassiar terrane. These, as well as ages from crosscutting plutonic suites of Early Jurassic (195-184 Ma), mid-Jurassic (ca. 176 Ma), Early Cretaceous (ca. 123 Ma), mid-Cretaceous (ca. 109 Ma) and Late Cretaceous (ca. 74 Ma) age place limits on the identification, timing of internal deformation, and age of assembly of various terranes in the northern Cordillera.