Toroidal mantle flow through the western U.S. slab window

Abstract

Research Article| April 01, 2008 Toroidal mantle flow through the western U.S. slab window G. Zandt; G. Zandt 1Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA Search for other works by this author on: GSW Google Scholar E. Humphreys E. Humphreys 2Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403, USA Search for other works by this author on: GSW Google Scholar Author and Article Information G. Zandt 1Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA E. Humphreys 2Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403, USA Publisher: Geological Society of America Received: 26 Jul 2007 Revision Received: 05 Dec 2007 Accepted: 07 Dec 2007 First Online: 03 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2008 Geological Society of America Geology (2008) 36 (4): 295–298. https://doi.org/10.1130/G24611A.1 Article history Received: 26 Jul 2007 Revision Received: 05 Dec 2007 Accepted: 07 Dec 2007 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation G. Zandt, E. Humphreys; Toroidal mantle flow through the western U.S. slab window. Geology 2008;; 36 (4): 295–298. doi: https://doi.org/10.1130/G24611A.1 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 circular pattern of anisotropic fast-axis orientations of split SKS arrivals observed in the western U.S. cannot be attributed reasonably to either preexisting lithospheric fabric or to asthenospheric strain related to global-scale plate motion. A plume origin for this pattern accounts more successfully for the anisotropy field, but little evidence exists for an active plume beneath central Nevada. We suggest that mantle flow around the edge of the sinking Gorda–Juan de Fuca slab is responsible for creating the observed anisotropy. Seismic images and kinematic reconstructions of Gorda–Juan de Fuca plate subduction have the southern edge of this plate extending from the Mendocino triple junction to beneath central Nevada, and flow models of narrow subducted slabs produce a strong toroidal flow field around the edge of the slab, consistent with the observed pattern of anisotropy. This flow may enhance uplift, extension, and magmatism of the northern Basin and Range while inhibiting extension of the southern Basin and Range. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.