A catalogue of late Cenozoic tephra beds in the Klondike goldfields and adjacent areas, Yukon Territory1Yukon Geological Survey Contribution 010.

Abstract

Many distal tephra beds exist in the late Cenozoic sediments of the Klondike goldfields and nearby areas. They come from volcanoes in the Wrangell volcanic field and the eastern Aleutian arc and represent large-magnitude eruptions. During the course of our tephrochronological studies in this region over the last 40 years, we have discovered 196 tephra occurrences and 50 distinctive tephra beds. The location of these sites and the distinguishing features of each of these tephra beds are presented in the form of a catalogue, which we hope will provide a stimulus for present and future tephrochronological studies in the Yukon Territory. These data are presented as a series of tables, as follows: location, stratigraphic context, petrography, geochemical characteristics, including major- and trace-element composition of glass shards, major-element composition of Fe–Ti oxides, classification, and age determinations. A new classification scheme is presented in which the rhyolitic and dacitic tephra beds are grouped into three classes: adakite, transitional, and typical arc.