Timing of early Tertiary ridge subduction in southern Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1992
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Abstract
We present a new compilation of 158 isotopic ages from Tertiary plutons that intrude the accretionary prism (Chugach-Prince William composite terrane) of southern Alaska. Two broad plutonic age groups are present: Paleocene to Eocene (the Sanak-Baranof plutonic belt), and Oligocene to Miocene. Plutons of the Sanak-Baranof belt are broadly coeval with magmatism along the axis of an Andean-type arc that lay farther inboard. A plot of age versus position along strike shows that near-trench magmatism progressed from about 66-63 Ma in the west to about 50 Ma in the east. We interpret the near-trench magmatism as the product of subduction of the Kula Farallon ridge (or another unidentified spreading center) and suggest that the age progression tracks a migrating trench-ridge-trench triple junction along the continental margin.
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Timing of early Tertiary ridge subduction in southern Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1992 |
| Series title | Bulletin |
| Series number | 2068 |
| DOI | 10.3133/70180223 |
| Year Published | 1993 |
| Language | English |
| Publisher | U.S. Government Printing Office |
| Publisher location | Washington, D.C. |
| Contributing office(s) | Alaska Science Center, Alaska Science Center Geology Minerals, Central Mineral and Environmental Resources Science Center |
| Description | 15 p. |
| Larger Work Type | Report |
| Larger Work Subtype | USGS Numbered Series |
| Larger Work Title | Geologic studies in Alaska by the U.S. Geological Survey, 1992 (Bulletin 2068) |
| First page | 163 |
| Last page | 177 |
| Country | United States |
| State | Alaska |
| Google Analytic Metrics | Metrics page |