Old Crow tephra found at the Palisades of the Yukon, Alaska

A 20-cm-thick volcanic ash layer at the Palisades along the Yukon River is geochemically correlated with the Old Crow tephra. A buried organic and wood-rich layer above the Old Crow tephra probably records the last interglaciation. The recognition of the Old Crow tephra provides the first chronologic information on the age of the thick sequence of Pleistocene sediments at the Palisades, an important ice-age mammal site in central Alaska and a key locakity for the reconstruction of the history of the Yukon River and the last interglaciation in central Alaska.