Old Crow tephra: A new late Pleistocene stratigraphic marker across north-central Alaska and western Yukon Territory
Quaternary Research
By: J.A. Westgate, T. D. Hamilton, and M.P. Gorton
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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.
Suggested Citation
Westgate, J., Hamilton, T.D., Gorton, M., 1983, Old Crow tephra: A new late Pleistocene stratigraphic marker across north-central Alaska and western Yukon Territory: Quaternary Research, v. 19, no. 1, p. 38-54, https://doi.org/10.1016/0033-5894(83)90026-1.
| 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 |
| Publication Date | January 20, 2017 |
| Year Published | 1983 |
| Language | English |
| Publisher | Elsevier |
| Publisher location | Amsterdam, Netherlands |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Quaternary Research |
| First page | 38 |
| Last page | 54 |