U-Pb Zircon Age Data for Selected Sedimentary, Metasedimentary, and Igneous Rocks from Northern and Central Alaska

Introduction

This publication contains the complete results of U-Pb zircon age dating studies of sedimentary and metasedimentary units from northern and central Alaska that are discussed and interpreted in other reports by the author. Most of the U-Pb ages are of detrital zircons from sandstones, although U-Pb ages from igneous and sedimentary clasts from conglomerates in some of those same units are also included. In addition to the data presented in the interpretive reports, this publication includes data that were excluded due to discordance, analytical problems, and publication space limitations. The U-Pb age data are reported in Excel-file format so that they can be easily downloaded and referenced or reinterpreted by future workers.

Data from two studies are included in this report. The first study, by Dumoulin and others (2013), reported the detrital zircon U-Pb age analysis of a single sample from the Upper Mississippian Ikalukrok unit of the Kuna Formation (table 1). The second study is that of Moore and others (in press), which focuses on the Upper Jurassic and Lower Cretaceous part of the Brookian sequence in the western Brooks Range (17 samples; table 2). For the latter study, samples were analyzed from the following units (1) the Upper Jurassic unit, Jw, of Curtis and others (1984), (2) the Lower Cretaceous Igrarok Hills unit of Moore and others (2002), (3) the Upper Jurassic and Lower Cretaceous Okpikruak Formation, (4) the Lower Cretaceous lower Brookian shale of Mull (1995), (5) the Lower Cretaceous Mount Kelly Graywacke Tongue of the Fortress Mountain Formation, (6) and the upper Lower Cretaceous Nanushuk Formation as redefined by Mull and others (2003). The results for each study are reported in separate Excel files, with individual samples in each study being shown as separate sheets within the files. The analyses of individual zircons are listed separately on the sheet according to the filtering schemes of the study and by the type of mass spectrometer used.

First posted November 20, 2014