CaltechAUTHORS
  A Caltech Library Service

U-Pb geochronology of mid-Cretaceous and Tertiary plutons along the western edge of the Coast Mountains, Revillagigedo Island, and Portland Peninsula, southeast Alaska

Rubin, Charles M. and Saleeby, Jason B. (2000) U-Pb geochronology of mid-Cretaceous and Tertiary plutons along the western edge of the Coast Mountains, Revillagigedo Island, and Portland Peninsula, southeast Alaska. In: Tectonics of the Coast Mountains, Southeastern Alaska and British Columbia. Special papers (Geological Society of America). No.343. Geological Society of America , Boulder, CO, pp. 145-157. ISBN 9780813723433. https://resolver.caltech.edu/CaltechAUTHORS:20140904-131500847

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20140904-131500847

Abstract

U-Pb geochronologic and field studies demonstrate that steeply dipping, highly deformed, sheet-like tonalitic to granodiorite plutons along the western flank of the Coast Mountains in the Ketchikan, Alaska, region were emplaced in two distinct episodes, between 105 and 90 Ma and ca. 65 and 50 Ma. A nondeformed tonalitic body that postdates deformation yields an Oligocene age. U-Pb ages from zircon further suggest that mid-Cretaceous plutons are younger northeastward. In the Ketchikan region, magmatism migrated northeastward and probably reflects a migration of the mid-Cretaceous arc between 105 and 90 Ma. Proterozoic inheritance in zircon indicates the presence or provenance of old crustal rocks. Thus, the assimilation of old crustal material played a role in the petrogenesis of the Coast Plutonic Complex. Mid-Cretaceous plutons intrude all basement constituents on the western flank of the Coast Mountains, including juvenile, mantle-derived material of the Alexander terrane and reworked older continental crustal fragments of the Taku terrane, confirming that the two terranes must have been adjacent at the time of mid-Cretaceous arc magmatism.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1130/0-8137-2343-4.145DOIArticle
http://specialpapers.gsapubs.org/content/343/145PublisherArticle
Additional Information:© 2000 Geological Society of America. Manuscript accepted by the Society June 20, 1999. Parts of this research were supported by the National Science Foundation grants EAR-86-05386 and EAR-88-034834 (to Saleeby). Additional support (to Rubin) was provided by a Geological Society of America Penrose grant, a Sigma-Xi grant-in-aid, the United States Geological Survey, Alaska Branch, and the United States Forest Service, Ketchikan Ranger District. George Gehrels, Bill McClelland, and Jim Mortensen are thanked for critically reading an earlier version of the manuscript. The manuscript was carefully reviewed by J. Brian Mahoney and Carl Isachsen; their help is gratefully acknowledged. We thank Fred Barker, Dave Brew, Bill McClelland, M. Meghan Miller, Jim Monger, and Margi Rusmore for helpful discussions on northern Cordillera tectonics. Jeff Marshall assisted in mapping part of the area during the summer of 1987.
Funders:
Funding AgencyGrant Number
NSFEAR-86-05386
NSFEAR-88-034834
Geological Society of America Penrose Bequest Research GrantsUNSPECIFIED
Sigma-Xi Grants in AidUNSPECIFIED
USGS Alaska BranchUNSPECIFIED
U.S. Forest ServiceUNSPECIFIED
Series Name:Special papers (Geological Society of America)
Issue or Number:343
Record Number:CaltechAUTHORS:20140904-131500847
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140904-131500847
Official Citation:Rubin, C. M., and Saleeby, J., 2000, U-Pb geochronology of mid-Cretaceous and Tertiary plutons along the western edge of the Coast Mountains, Revillagigedo Island, and Portland Peninsula, southeast Alaska, in Stowell, H. H., and McClelland, W. C., eds., Tectonics of the Coast Mountains, Southeastern Alaska and British Columbia: Boulder, Colorado, Geological Society of America Special Paper 343
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:49247
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:05 Sep 2014 23:30
Last Modified:03 Oct 2019 07:12

Repository Staff Only: item control page