Journal article
U-Pb geochronology of two pre-Tertiary plutons in the Coast Mountains Batholith near Ketchikan, southeastern Alaska
Canadian journal of earth sciences, Vol.28(6), pp.894-898
Geological Association of Canada--Mineralogical Association of Canada (GAC-MAC) annual general meeting, symposium on Geological transect: northwestern Canadian Cordillera
06/1991
DOI: 10.1139/e91-081
Abstract
U-Pb geochronological studies indicate that the central part of the Coast Mountains batholith in the Ketchikan area contains plutons of Triassic and possibly mid-Palaeozoic age in addition to the previously recognized early Tertiary plutons. Zircons from a foliated granodiorite in Burroughs Bay yield an upper concordia intercept of 336 +- 34 m.y., which is tentatively interpreted as the age of crystallization, and a lower intercept of 79 +- 7 m.y., which may record extreme Pb loss and growth of metamorphic zircon during amphibolite- to granulite-facies metamorphism. Zircons from a tonalite in Boca de Quadra yield an upper intercept (age of crystallization) of 215 +- 15 m.y. and a lower intercept (Pb-loss age) of 50 +- 20 m.y. The presence of these Triassic and possibly mid-Palaeozoic plutons supports previous interpretations that pre- Tertiary rocks in this part of the batholith may belong to the Yukon-Tanana terrain.
Details
- Title: Subtitle
- U-Pb geochronology of two pre-Tertiary plutons in the Coast Mountains Batholith near Ketchikan, southeastern Alaska
- Creators
- George E Gehrels - University of ArizonaWilliam C McClelland - University of ArizonaScott D Samson - University of ArizonaJay L Jackson - University of ArizonaP. Jonathan Patchett - University of Arizona
- Contributors
- R. G Anderson (Editor) - Geol. Surv. Can., Cordilleran Div. Vancouver, BC CAN Canada
- Resource Type
- Journal article
- Publication Details
- Canadian journal of earth sciences, Vol.28(6), pp.894-898
- Conference
- Geological Association of Canada--Mineralogical Association of Canada (GAC-MAC) annual general meeting, symposium on Geological transect: northwestern Canadian Cordillera
- Publisher
- National Research Council of Canada
- DOI
- 10.1139/e91-081
- ISSN
- 0008-4077
- eISSN
- 1480-3313
- Alternative title
- Contributions to the geology and geophysics of northwestern British Columbia and southeastern Alaska--Contributions a la geologie et a la geophysique du nord-ouest de la Colombie-Britannique et du sud-est de l'Alaska
- Language
- English; French
- Date published
- 06/1991
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9984229303102771
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