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The Hayes tephra deposits, and upper Holocene marker horizon in south-central Alaska

Quaternary Research

By:
, , and
DOI: 10.1016/0033-5894(90)90056-Q

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Abstract

The most widespread of all Holocene tephra deposits in the Cook Inlet region of south-central Alaska is a set of deposits from Hayes volcano. Because of their unique phenocryst content-biotite in rare amounts and a high proportion of amphibole to pyroxene-the deposits are readily identifiable at all but the most distant sites where they are very fine grained. Eighteen radiocarbon dates from eight upland sites limit the age of the tephra set to between about 3500 and 3800 yr. The set originated at Hayes volcano in the Tordrillo Mountains 150 km northwest of Anchorage; seven or possibly eight closely succeeding deposits, low-silica dacite in composition, compose two main lobes that extend northeast for 400 km and south for at least 250 km from the vent. We estimate the total tephra volume to be 10 km3; multiple layers imply four to six larger and two or three smaller eruptions. The deposits are a nearly isochronous marker horizon that should be useful in future archeologic, geologic, and palynologic studies in the region. ?? 1990.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The Hayes tephra deposits, and upper Holocene marker horizon in south-central Alaska
Series title:
Quaternary Research
DOI:
10.1016/0033-5894(90)90056-Q
Volume
33
Issue:
3
Year Published:
1990
Language:
English
Publisher:
Elsevier
Publisher location:
Amsterdam, Netherlands
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Quaternary Research
First page:
276
Last page:
290
Number of Pages:
15