Detrital zircon geochronology of quartzose metasedimentary rocks from parautochthonous North America, east-central Alaska

We report eight new U-Pb detrital zircon ages for quartzose metasedimentary rocks from four lithotectonic units of parautochthonous North America in east-central Alaska: the Healy schist, Keevy Peak Formation, and Sheep Creek Member of the Totatlanika Schist in the northern Alaska Range, and the Butte assemblage in the northwestern Yukon-Tanana Upland. Excepting 1 of 3 samples from the Healy schist, all have dominant detrital zircon populations of 1.9-1.8 Ga and a subordinate population of 2.7-2.6 Ga. Three zircons from Totatlanika Schist yield the youngest age of ca. 780 Ma. The anomalous Healy schist sample has abundant 1.6-0.9 Ga detrital zircon, as well as populations at 2.0-1.8 Ga and 2.7-2.5 Ga that overlap the ages from the rest of our samples; it has a minimum age population of ca. 1007 Ma.