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.
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 |
| Google Analytic Metrics | Metrics page |