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Marine tephrochronology of the Mt. Edgecumbe volcanic field, southeast Alaska, USA

Quaternary Research

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DOI: 10.1016/j.yqres.2009.10.007

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Abstract

The Mt. Edgecumbe Volcanic Field (MEVF), located on Kruzof Island near Sitka Sound in southeast Alaska, experienced a large multiple-stage eruption during the last glacial maximum (LGM)-Holocene transition that generated a regionally extensive series of compositionally similar rhyolite tephra horizons and a single well-dated dacite (MEd) tephra. Marine sediment cores collected from adjacent basins to the MEVF contain both tephra-fall and pyroclastic flow deposits that consist primarily of rhyolitic tephra and a minor dacitic tephra unit. The recovered dacite tephra correlates with the MEd tephra, whereas many of the rhyolitic tephras correlate with published MEVF rhyolites. Correlations were based on age constraints and major oxide compositions of glass shards. In addition to LGM-Holocene macroscopic tephra units, four marine cryptotephras were also identified. Three of these units appear to be derived from mid-Holocene MEVF activity, while the youngest cryptotephra corresponds well with the White River Ash eruption at not, vert, similar 1147 cal yr BP. Furthermore, the sedimentology of the Sitka Sound marine core EW0408-40JC and high-resolution SWATH bathymetry both suggest that extensive pyroclastic flow deposits associated with the activity that generated the MEd tephra underlie Sitka Sound, and that any future MEVF activity may pose significant risk to local population centers.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Marine tephrochronology of the Mt. Edgecumbe volcanic field, southeast Alaska, USA
Series title:
Quaternary Research
DOI:
10.1016/j.yqres.2009.10.007
Volume
73
Issue:
2
Year Published:
2010
Language:
English
Publisher:
Elsevier
Publisher location:
Amsterdam, Netherlands
Contributing office(s):
Geology and Environmental Change Science Center
Description:
16 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Quaternary Research
First page:
277
Last page:
292
Country:
United States
State:
Alaska
Other Geospatial:
Mt. Edgecumbe Volcanic Field