Internal deformation of the southern Gorda plate: Fragmentation of a weak plate near the Mendocino triple junction

Research Article| August 01, 2001 Internal deformation of the southern Gorda plate: Fragmentation of a weak plate near the Mendocino triple junction Sean P.S. Gulick; Sean P.S. Gulick 1Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA Search for other works by this author on: GSW Google Scholar Anne S. Meltzer; Anne S. Meltzer 1Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA Search for other works by this author on: GSW Google Scholar Timothy J. Henstock; Timothy J. Henstock 2Department of Geology and Geophysics, Rice University, Houston, Texas 77005, USA Search for other works by this author on: GSW Google Scholar Alan Levander Alan Levander 2Department of Geology and Geophysics, Rice University, Houston, Texas 77005, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Sean P.S. Gulick 1Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA Anne S. Meltzer 1Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015, USA Timothy J. Henstock 2Department of Geology and Geophysics, Rice University, Houston, Texas 77005, USA Alan Levander 2Department of Geology and Geophysics, Rice University, Houston, Texas 77005, USA Publisher: Geological Society of America Received: 26 Oct 2000 Revision Received: 27 Mar 2001 Accepted: 10 Apr 2001 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2001) 29 (8): 691–694. https://doi.org/10.1130/0091-7613(2001)029<0691:IDOTSG>2.0.CO;2 Article history Received: 26 Oct 2000 Revision Received: 27 Mar 2001 Accepted: 10 Apr 2001 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 Sean P.S. Gulick, Anne S. Meltzer, Timothy J. Henstock, Alan Levander; Internal deformation of the southern Gorda plate: Fragmentation of a weak plate near the Mendocino triple junction. Geology 2001;; 29 (8): 691–694. doi: https://doi.org/10.1130/0091-7613(2001)029<0691:IDOTSG>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 North-south compression across the Gorda-Pacific plate boundary caused by the northward-migrating Mendocino triple junction appears to reactivate Gorda plate normal faults, originally formed at the spreading ridge, as left-lateral strike-slip faults. Both seismically imaged faults and magnetic anomalies fan eastward from ∼N20°E near the Gorda ridge to ∼N75°E near the triple junction. Near the triple junction, the Gorda plate is faulted pervasively and appears to be extending east-southeast as it subducts beneath North America. Continuation of northeast-southwest–oriented deformation in the southern Gorda plate beneath the continental margin contrasts with the northwest-southeast–trending structures in the overlying accretionary prism, suggesting partial Gorda–North American plate decoupling. Southeast of the triple junction, a slabless window is generated by removal of the subducting Gorda plate. Southwest of the triple junction, the Pacific plate acts as a rigid barrier forcing southern Gorda crust to rotate clockwise, fragment, and flow into the slabless window. Net clockwise rotation of the southern Gorda crust forms a boundary with the nonrotating northern Gorda plate, which is observed as a bend in the magnetic anomalies. This boundary, which is compressional on the western end and extensional to the east, may separate the stress regime of the southern Gorda plate from the remainder of the Cascadia subduction zone. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.