Conference proceeding
U-Pb and Hf isotopic analyses of detrital zircons from the Taku Terrane, Southeast Alaska
Abstracts with programs - Geological Society of America, Vol.45(7), p.166
Geological Society of America, 2013 annual meeting & exposition
2013
Abstract
In the southeast Alaskan panhandle, amidst the folded, faulted, and accreted terranes, sits the Taku terrane. Previous workers have defined, and re-defined the terrane, and it is currently identified as a package of 3 units; Carboniferous(?)-Permian strata of the Windham Group, Permian strata of the Gastineau Group, and Triassic strata of the Perseverance Group. These strata are structurally overlain to the east by the Yukon-Tanana terrane (YTT) and structurally overlie Jurassic-Cretaceous strata of the Gravina belt to the west. For this study we have collected 583 U-Pb ages and 74 Hf isotope determinations from detrital zircon grains of six samples in locations between Juneau and Ketchikan. Two samples from the Windham Group yield predominantly 360-400 Ma grains (peak age of 383 Ma) and one grain of approximately 437 Ma. Epsilon Hf values for these grains are highly variable, ranging from +16 to -3. One sample from the Gastineau Group yields a similar age group of 350-395 Ma (age peak of 370 Ma). Two samples of the Perseverance Group have a dominant age group of 340-385 Ma (peak age of 363 Ma) and subordinate age groups of 410-460 Ma and 220-290 Ma. Epsilon Hf values for the 340-385 Ma grains are highly variable, ranging from +10 to -18, whereas the 410-460 Ma grains are all juvenile (epsilon Hf values of +7 to +14). One additional sample of the Gastineau Group yields very different ages, with main age groups of 275-300 Ma (peak age of 292 Ma) and 400-460 Ma (peak age of 435 Ma). Hf isotopic compositions of the 400-460 Ma grains are highly juvenile (+10 to +16), whereas compositions for the 275-300 Ma grains are intermediate (+5 to +10) in value. Collectively these data support previous suggestions that most sediment in the Taku terrane was shed from the Yukon-Tanana terrane, and also demonstrate that some sediment was derived from the Alexander terrane during Permian and Triassic time.
Details
- Title: Subtitle
- U-Pb and Hf isotopic analyses of detrital zircons from the Taku Terrane, Southeast Alaska
- Creators
- Dominique Giesler - University of ArizonaGeorge GehrelsWilliam C McClellandMark PechaIntan YokelsonChelsi WhiteMauricio IbanezF. K MazdabDon Willson
- Resource Type
- Conference proceeding
- Publication Details
- Abstracts with programs - Geological Society of America, Vol.45(7), p.166
- Conference
- Geological Society of America, 2013 annual meeting & exposition
- Publisher
- Geological Society of America (GSA)
- ISSN
- 0016-7592
- Alternative title
- Geological Society of America, 2013 annual meeting & exposition
- Language
- English
- Date published
- 2013
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229178002771
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