Six distal tephra beds from the Yukon Territory and Alaska were dated by the fission-track method. Assuming that no track fading has occurred in the glass, Old Crow and Dawson tephra beds are <120 000 and <52 000 yr old, respectively. Mosquito Gulch tephra is 1.22 m.y. old, Fort Selkirk tephra is approx 1 m.y. old, the Ester ash bed is 0.45 m.y. old, and the best estimate of the age of Lost Chicken tephra is in the range 1.7-2.6 m.y. It is concluded that application of the fission-track method to distal tephra, in conjunction with detailed characterization studies, offers great potential for elucidation of the Late Cainozoic geological history of Alaska and the Yukon Territory. -P.Br.
Additional publication details
Fission-track ages of late Cenozoic distal tephra beds in the Yukon Territory and Alaska.