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Old Crow tephra: A new late Pleistocene stratigraphic marker across north-central Alaska and western Yukon Territory

Quaternary Research

By:
, ,
DOI: 10.1016/0033-5894(83)90026-1

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Abstract

Old Crow tephra is the first extensive Pleistocene tephra unit to be documented in the northwestern part of North America. It has a calc-alkaline dacitic composition with abundant pyroxene, plagioclase, and FeTi oxides, and minor hornblende, biotite, apatite, and zircon. Thin, clear, bubble-wall fragments are the dominant type of glass shard. This tephra can be recognized by its glass and phenocryst compositions, as determined by X-ray fluorescence, microprobe, and instrumental neutron activation techniques. It has an age between the limits of 60,000 and 120,000 yr, set by 14C and fission-track measurements, respectively. Old Crow tephra has been recognized in the Koyukuk Basin and Fairbanks region of Alaska, and in the Old Crow Lowlands of the northern Yukon Territory, some 600 km to the east-northeast. The source vent is unknown, but these occurrences, considered in relation to the distant locations of potential Quaternary volcanic sources, demonstrate the widespread distribution of this tephra and underscore its importance as a regional stratigraphic marker. ?? 1983.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Old Crow tephra: A new late Pleistocene stratigraphic marker across north-central Alaska and western Yukon Territory
Series title:
Quaternary Research
DOI:
10.1016/0033-5894(83)90026-1
Volume
19
Issue:
1
Year Published:
1983
Language:
English
Publisher:
Elsevier
Publisher location:
Amsterdam, Netherlands
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
38
Last page:
54
Number of Pages:
17