U-Pb zircon and monazite ages for the Okanogan Range batholith, Washington: Implications for the magmatic and tectonic evolution of the southern Canadian and northern United States Cordillera

Abstract

Research Article| February 01, 1993 U-Pb zircon and monazite ages for the Okanogan Range batholith, Washington: Implications for the magmatic and tectonic evolution of the southern Canadian and northern United States Cordillera HUGH A. HURLOW; HUGH A. HURLOW 1Department of Geological Sciences, University of Washington, Seattle, Washington 98195 Search for other works by this author on: GSW Google Scholar BRUCE K. NELSON BRUCE K. NELSON 1Department of Geological Sciences, University of Washington, Seattle, Washington 98195 Search for other works by this author on: GSW Google Scholar Author and Article Information HUGH A. HURLOW 1Department of Geological Sciences, University of Washington, Seattle, Washington 98195 BRUCE K. NELSON 1Department of Geological Sciences, University of Washington, Seattle, Washington 98195 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1993) 105 (2): 231–240. https://doi.org/10.1130/0016-7606(1993)105<0231:UPZAMA>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation HUGH A. HURLOW, BRUCE K. NELSON; U-Pb zircon and monazite ages for the Okanogan Range batholith, Washington: Implications for the magmatic and tectonic evolution of the southern Canadian and northern United States Cordillera. GSA Bulletin 1993;; 105 (2): 231–240. doi: https://doi.org/10.1130/0016-7606(1993)105<0231:UPZAMA>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract New U-Pb zircon and monazite dates for the Okanogan Range batholith, a suite of trondhjemitic plutonic rocks in north-central Washington, are interpreted to reflect minimum crystallization ages of 114-111 Ma. These new data suggest that the Okanogan Range batholith may represent an older southerly segment of the late Albian Spences Bridge Group, which crops out in southern British Columbia. This would constitute a >300-km-long, north-northwest-trending belt of 130-100 Ma volcanic and plutonic rocks along the western margin of the Intermontane belt, herein named the Okanogan-Spences Bridge arc. The Okanogan-Spences Bridge arc and the Gambier arc in the Coast belt of British Columbia were coeval, widely separated Early Cretaceous magmatic belts in the southern Canadian-northern United States Cordillera. The cbronologic data require reevaluation of models proposing one versus two east-dipping subduction zones to explain the origin of these two parallel magmatic belts. Neither model adequately reconciles all geologic observations. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.