Implications of Plate Tectonics for the Cenozoic Tectonic Evolution of Western North America

Abstract

Research Article| December 01, 1970 Implications of Plate Tectonics for the Cenozoic Tectonic Evolution of Western North America TANYA ATWATER TANYA ATWATER University of California, San Diego, Marine Physical Laboratory of the Scripps Institution of Oceanography, La Jolla, California 92037 AUTHOR'S PRESENT ADDRESS: GEOPHYSICS DEPARTMENT, SCHOOL OF EARTH SCIENCES, STANFORD UNIVERSITY, STANFORD, CALIFORNIA 94305 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1970) 81 (12): 3513–3536. https://doi.org/10.1130/0016-7606(1970)81[3513:IOPTFT]2.0.CO;2 Article history received: 15 Apr 1970 rev-recd: 09 Jul 1970 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation TANYA ATWATER; Implications of Plate Tectonics for the Cenozoic Tectonic Evolution of Western North America. GSA Bulletin 1970;; 81 (12): 3513–3536. doi: https://doi.org/10.1130/0016-7606(1970)81[3513:IOPTFT]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 SocietyGSA Bulletin Search Advanced Search Abstract Magnetic anomaly patterns in the northeast Pacific Ocean combined with plate theory indicate that a trench existed offshore from western North America during mid-Tertiary time and that the present episode of strike-slip motion in the San Andreas fault system originated after the cessation of subduction, not earlier than 30 m.y. ago. At present, the American and Pacific plates appear to be moving past one another parallel to the San Andreas fault at a rate of 6 cm/yr. Data concerning the late Cenozoic history of motions between these plates is inconclusive, and so 2 probable models are examined. One assumes a constant motion of 6 cm/yr throughout the late Cenozoic, whereas the other assumes that the 2 plates were fixed with respect to one another until 5 m.y. ago, at which time they broke along the San Andreas fault system and began moving at 6 cm/yr. The second model implies that the San Andreas fault took up all the motion at the boundary between the North American and Pacific plates, while the first model suggests the broader view that much of the late Cenozoic tectonic activity of western North America is related to this boundary deformation. The models make testable predictions for the distribution of igneous rocks and for the total amount and timing of deformation expected. Extrapolation of the model of constant motions to the early Cenozoic suggests an era of slightly compressional strike-slip at the edge of North America. A major change in plate motions in late Mesozoic time is suggested. 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.