A new set of basaltic tephras from southeastern Alaska represent key stratigraphic markers for the late Pleistocene

Quaternary Research
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Abstract

An 8-cm-thick black basaltic tephra with nine discrete normally graded beds is present in cores from a lake on Baker Island in southeastern Alaska. The estimated age of the tephra is 13,492 ± 237 cal yr BP. Although similar in age to the MEd tephra from the adjacent Mt. Edgecumbe Volcanic Field, this tephra is geochemically distinct. Black basaltic tephras recovered from two additional sites in southeastern Alaska, Heceta Island and the Gulf of Esquibel, are also geochemically distinct from the MEd tephra. The age of the tephra from Heceta Island is 14,609 ± 343 cal yr BP. Whereas the tephras recovered from Baker Island/Heceta Island/Gulf of Esquibel are geochemically distinct from each other, similarities in the ages of these tephras and the MEd tephra suggest a shared eruptive trigger, possibly crustal unloading caused by retreat of the Cordilleran Ice Sheet. The submerged Addington Volcanic Field on the continental shelf, which may have been subaerially exposed during the late Pleistocene, is a possible source for the southeastern Alaska tephras

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Publication type Article
Publication Subtype Journal Article
Title A new set of basaltic tephras from southeastern Alaska represent key stratigraphic markers for the late Pleistocene
Series title Quaternary Research
DOI 10.1017/qua.2018.154
Volume 92
Issue 1
Year Published 2019
Language English
Publisher Cambridge University Press
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 11 p.
First page 246
Last page 256
Country United States
State Alaska
Other Geospatial Southeastern Alaska
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