Miocene peralkaline volcanism in west-central British Columbia — Its temporal and plate-tectonics setting

Abstract

Research Article| August 01, 1979 Miocene peralkaline volcanism in west-central British Columbia — Its temporal and plate-tectonics setting Mary Lou Bevier; Mary Lou Bevier 1Department of Geological Sciences, University of California, Santa Barbara, California 93106 Search for other works by this author on: GSW Google Scholar Richard Lee Armstrong; Richard Lee Armstrong 2Department of Geological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1W 5, Canada Search for other works by this author on: GSW Google Scholar J. G. Souther J. G. Souther 3Geological Survey of Canada, 100 West Pender Street, Vancouver, British Columbia V6B 1 R8, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Mary Lou Bevier 1Department of Geological Sciences, University of California, Santa Barbara, California 93106 Richard Lee Armstrong 2Department of Geological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1W 5, Canada J. G. Souther 3Geological Survey of Canada, 100 West Pender Street, Vancouver, British Columbia V6B 1 R8, Canada Publisher: Geological Society of America First Online: 02 Jun 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 Geological Society of America Geology (1979) 7 (8): 389–392. https://doi.org/10.1130/0091-7613(1979)7<389:MPVIWB>2.0.CO;2 Article history First Online: 02 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 Mary Lou Bevier, Richard Lee Armstrong, J. G. Souther; Miocene peralkaline volcanism in west-central British Columbia — Its temporal and plate-tectonics setting. Geology 1979;; 7 (8): 389–392. doi: https://doi.org/10.1130/0091-7613(1979)7<389:MPVIWB>2.0.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 SocietyGeology Search Advanced Search Abstract The 600-km-long Anahim volcanic belt of upper Miocene-Quaternary alkalic and peralkalic volcanic centers trends east-west along approximately lat 52°N in British Columbia, in contrast to the Miocene Pemberton volcanic belt of calc-alkalic centers and the Pliocene-Quaternary Garibaldi volcanic belt of calc-alkalic centers, which follow the northwest-trending continental margin. Anahim belt rock types range from alkali basalt and nephelinite, found as small cinder cones and flows, to oversaturated (and undersaturated) peralkalic varieties found in evolved central volcanoes and in their erosion-exposed roots. In contrast to the usual subduction-related calc-alkaline volcanism in the Pemberton and Garibaldi belts, volcanic activity in the Anahim belt has been linked with lithospheric fracturing above the northern edge of the subducted Juan de Fuca plate or interpreted as an edge effect of the subducted plate in the mantle. Available isotopic ages from the oldest centers in the Anahim belt become younger eastward at a rate of 2 to 3.3 cm/yr, suggesting that volcanic activity there may well be related to a mantle hot spot beneath British Columbia. Volcanic chemistry and isotopic composition do not distinguish between either a rift or a hot-spot setting. 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.