Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska
Professional Paper
1709-D
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Abstract
High-precision 40Ar/39Ar geochronology of selected lavas from Westdahl Volcano places time constraints on several key prehistoric eruptive phases of this large active volcano. A dike cutting old pyroclastic-flow and associated lahar deposits from a precursor volcano yields an age of 1,654+/-11 k.y., dating this precursor volcano as older than early Pleistocene. A total of 11 geographically distributed lavas with ages ranging from 47+/-14 to 127+/-2 k.y. date construction of the Westdahl volcanic center. Lava flows cut by an apparent caldera-rim structure yielded ages of 81+/-5 and 121+/-8 k.y., placing a maximum date of 81 ka on caldera formation. Late Pleistocene and Holocene lavas fill the caldera, but most of them are obscured by the large summit icecap.
Suggested Citation
Calvert, A.T., Moore, R.B., and McGimsey, R.G., 2005, Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska: U.S. Geological Survey Professional Paper 1709, 16 p., https://doi.org/10.3133/pp1709D.
ISSN: 2330-7102 (online)
Study Area
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska |
| Series title | Professional Paper |
| Series number | 1709 |
| Chapter | D |
| DOI | 10.3133/pp1709D |
| Year Published | 2005 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Contributing office(s) | Volcano Hazards Program |
| Description | 16 p. |
| Country | United States |
| State | Alaska |
| Other Geospatial | Westdahl Volcano |
| Online Only (Y/N) | Y |