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Old Crow Tephra: A New Late Pleistocene Stratigraphic Marker Across North-Central Alaska and Western Yukon Territory

Published online by Cambridge University Press:  20 January 2017

John A. Westgate
Affiliation:
Department of Geology, University of Toronto, Toronto, Ontario M5S 1A1, Canada Physical Sciences Division, Scarborough College, University of Toronto, West Hill, Ontario M1C 1A4, Canada
Thomas D. Hamilton
Affiliation:
U.S. Geological Survey, Gould Hall, APU Campus, University Drive, Anchorage, Alaska 99504 USA
Michael P. Gorton
Affiliation:
Department of Geology, University of Toronto, Toronto, Ontario M5S 1A1, Canada

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 Fe–Ti 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.

Type
Original Articles
Copyright
University of Washington

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References

Borchardt, G.A., Harward, M.E., Schmitt, R.A.. 1971. Correlation of volcanic ash deposits by activation analysis of glass separates. Quaternary Research 1. 247260.Google Scholar
Buddington, A.F., Lindsley, D.H.. 1964. Iron-titanium oxide minerals and synthetic equivalents. Journal of Petrology 5. 310357.CrossRefGoogle Scholar
Denham, C.R.. 1976. Blake polarity episode in two cores from the Greater Antilles Outer Ridge. Earth and Planetary Science Letters 29. 422434.Google Scholar
Hamilton, T.D.. 1969. Glacial geology of the lower Alatna Valley, Brooks Range, Alaska. United States Contributions to Quaternary Research. Schumm, S.A., Bradley, W.C.Geological Society of America Special Paper 123 181223.Google Scholar
Hamilton, T.D.. 1978. Late Cenozoic stratigraphy of the south-central Brooks Range. United States Geological Survey Circular 772-B. B36B38.Google Scholar
Hamilton, T.D.. 1979. Surficial geologic map of the Wiseman quadrangle, Alaska. United States Geological Survey Miscellaneous Field Studies Map MF-1122, scale 1:250,000.Google Scholar
Hamilton, T.D.. 1980. Quaternary stratigraphic sections with radiocarbon dates, Wiseman quadrangle, Alaska. United States Geological Survey Open-File Report 80-791.Google Scholar
Hamilton, T.D.. 1981. Surficial geologic map of the Survey Pass quadrangle, Alaska. United States Geological Survey Miscellaneous Field Studies Map MF-1320, scale 1:250,000.Google Scholar
Hamilton, T.D.. 1982. A late Pleistocene glacial chronology for the southern Brooks Range—Stratigraphic record and regional significance. Geological Society of America Bulletin 93. 700716.Google Scholar
Hopkins, D.M.. 1967. The Cenozoic history of Beringia—A synthesis. The Bering Land Bridge. Hopkins, D.M.. Stanford Univ. Press, Stanford, Calif. 451484.Google Scholar
Hughes, O.L.. 1972. Surficial geology of northern Yukon Territory and northwestern District of Mackenzie, Northwest Territories. Geological Survey of Canada, Paper 69-36.Google Scholar
Inman, D.L.. 1952. Measures for describing the size distribution of sediments. Journal of Sedimentary Petrology 22. 125145.Google Scholar
Irvine, T.N., Baragar, W.R.A.. 1971. A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Sciences 8. 523548.Google Scholar
King, P.B.. 1969. Tectonic map of North America. United States Geological Survey, scale 1:5,000,000.Google Scholar
Morlan, R.E.. 1980. Taphonomy and archaeology in the Upper Pleistocene of the northern Yukon Territory: A glimpse of the peopling of the New World. National Museum of Man, Mercury Series, Paper No. 94.Google Scholar
Morlan, R.E.. 1983. Pleistocene archaeology in Old Crow Basin: A critical reappraisal Proceedings of the 10th Congress of the International Union of Prehistoric and Protohistoric SciencesMexico City, 1981 in press.Google Scholar
Morlan, R.E., Matthews, J.V. Jr.. 1978. New dates for early man. Geos 25 Winter.Google Scholar
Naeser, N.D., Westgate, J.A., Hughes, O.L., Péwé, T.L.. 1982. Fission-track ages of late Cenozoic distal tephra beds in the Yukon Territory and Alaska. Canadian Journal of Earth Sciences 19in press.CrossRefGoogle Scholar
Norrish, K., Chappell, B.W.. 1977. X-ray fluorescence spectrography. Physical Methods in Determinative Mineralogy. Zussman, J.. Academic Press, New York. 201.Google Scholar
Pearce, G.W., Westgate, J.A., Robertson, S.. 1982. Magnetic reversal history of Pleistocene sediments at Old Crow, northwestern Yukon Territory. Canadian Journal of Earth Sciences 19. 919929.CrossRefGoogle Scholar
Prest, V.K., Grant, D.R., Rampton, V.N.. 1967. Glacial map of Canada. Geological Survey of Canada, Map 1253A, scale 1:5,000,000.Google Scholar
Sarna-Wojcicki, A.M., Bowman, H.W., Russell, P.C.. 1979. Chemical correlation of some late Cenozoic tuffs of northern and central California by neutron activation analysis of glass and comparison with X-ray fluorescence analysis. U.S. Geological Survey, Professional Paper 1147.Google Scholar
Statham, P.J.. 1975. Quantitative X-Ray Energy Spectrometry; Application of Si(Li) Detector to Microprobe Analyses. Unpublished Ph.D. thesis. Cambridge University.Google Scholar
Taylor, S.R., Gorton, M.P.. 1977. Geochemical application of spark source mass spectrography. III. Element sensitivity, precision and accuracy. Geochemica et Cosmochemica Acta 41. 13751380.CrossRefGoogle Scholar
Westgate, J.A., Briggs, N.D.. 1980. Dating methods of Pleistocene deposits and their problems: V. Tephrochronology and fission-track dating. Geoscience Canada 7. 310.Google Scholar
Westgate, J.A., Gorton, M.P.. 1981. Correlation techniques in tephra studies. Tephra Studies. Self, S., Sparks, R.S.J. NATO Advanced Studies Institute Series. Reidel, Dordrecht. 7394.Google Scholar
Westgate, J.A., Péwé, T.L., Gorton, M.P.. 1982. Tephrochronology of the Gold Hill Loess in central Alaska. Geological Society of America, Abstracts with Programs 14. 645646.Google Scholar