Post-Laramide removal of the Farallon slab, western United States

Research Article| November 01, 1995 Post-Laramide removal of the Farallon slab, western United States Eugene D. Humphreys Eugene D. Humphreys 1Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403 Search for other works by this author on: GSW Google Scholar Author and Article Information Eugene D. Humphreys 1Department of Geological Sciences, University of Oregon, Eugene, Oregon 97403 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1995) 23 (11): 987–990. https://doi.org/10.1130/0091-7613(1995)0232.3.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 Eugene D. Humphreys; Post-Laramide removal of the Farallon slab, western United States. Geology 1995;; 23 (11): 987–990. doi: https://doi.org/10.1130/0091-7613(1995)0232.3.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 SocietyGeology Search Advanced Search Abstract I propose that post-Laramide removal of the subhorizontally subducting Farallon slab occurred by buckling downward along an approximately east-northeast–trending axis. This process was accomplished by a tearing or necking separation of the subducted slab near the northern and southern boundaries of the United States and propagation of the separated edges toward the central axis of downwelling, accompanied by aesthenosphic upwelling behind the trailing edges. Initial buckling probably began near 50 Ma, and slab removal was complete by 20 Ma. This model is based primarily on the space-time evolution of the “ignimbrite flare-up” (a major mid-Tertiary igneous event of mantle origin), which involved two propagating fronts of initiation of volcanism that followed the proposed motions of the separated slab edges as they converged on central Nevada from the north and southeast. Post-Laramide uplift, extension, establishment of the Cascadia subduction zone, and active magmatism may be consequences of lithosphere-scale modifications caused by the Laramide removal of the slab and the resulting asthenospheric upwelling. 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.