Tectonic geomorphology of marine terraces: Santa Barbara fold belt, California

Abstract

Research Article| January 01, 2014 Tectonic geomorphology of marine terraces: Santa Barbara fold belt, California Larry D. Gurrola; Larry D. Gurrola 1308 Hayes Avenue, Ventura, California 93003, USA Search for other works by this author on: GSW Google Scholar Edward A. Keller; Edward A. Keller † 2Department of Earth Science, University of California, Santa Barbara, California 93106, USA †E-mail: keller@geol.ucsb.edu Search for other works by this author on: GSW Google Scholar James H. Chen; James H. Chen 3Science Division, M/S 183-601, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, California 91109-8099, USA Search for other works by this author on: GSW Google Scholar Lewis A. Owen; Lewis A. Owen 4Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221, USA Search for other works by this author on: GSW Google Scholar Joel Q. Spencer Joel Q. Spencer 5Department of Geology, Kansas State University, 108 Thompson Hall, Manhattan, Kansas 66506-3201, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Larry D. Gurrola 1308 Hayes Avenue, Ventura, California 93003, USA Edward A. Keller † 2Department of Earth Science, University of California, Santa Barbara, California 93106, USA James H. Chen 3Science Division, M/S 183-601, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, California 91109-8099, USA Lewis A. Owen 4Department of Geology, University of Cincinnati, Cincinnati, Ohio 45221, USA Joel Q. Spencer 5Department of Geology, Kansas State University, 108 Thompson Hall, Manhattan, Kansas 66506-3201, USA †E-mail: keller@geol.ucsb.edu Publisher: Geological Society of America Received: 16 Nov 2009 Revision Received: 22 May 2013 Accepted: 08 Jul 2013 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2013 Geological Society of America GSA Bulletin (2014) 126 (1-2): 219–233. https://doi.org/10.1130/B30211.1 Article history Received: 16 Nov 2009 Revision Received: 22 May 2013 Accepted: 08 Jul 2013 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Larry D. Gurrola, Edward A. Keller, James H. Chen, Lewis A. Owen, Joel Q. Spencer; Tectonic geomorphology of marine terraces: Santa Barbara fold belt, California. GSA Bulletin 2014;; 126 (1-2): 219–233. doi: https://doi.org/10.1130/B30211.1 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 SocietyGSA Bulletin Search Advanced Search Abstract Uplifted marine terraces are common landforms in coastal regions where active tectonics are an important component of landscape evolution, such as along the coastal stretches of southern California. The pattern and elevation of shoreline angles on active folds provide information about rates of uplift and fold growth, which is important for defining tectonic models. A particularly impressive succession of marine terraces are developed across the Santa Barbara fold belt (SBFB) in southern California, which comprises an east-west linear zone of active folds and (mostly) blind faults on the coastal piedmont and in the Santa Barbara Channel. The fold belt is characterized by several flights of emergent late Pleistocene marine terraces uplifted and preserved on the flanks of active anticlines. At several locations along the fold belt, the first emergent marine terrace is numerically dated by methods that include uranium-series dating on terrace corals, 14C dating on terrace shells and detrital charcoal, optically stimulated luminescence of marine terrace sands, and oxygen isotopic signatures (δ18O) of mollusks. Individual marine terraces have as many as four ages, using up to three different dating methods, providing confidence in terrace chronology. Ages of higher terraces are estimated assuming a constant rate of uplift for a particular flight. Of the 31 terraces, 22 formed during a time of falling sea level, with 9 forming at or near marine oxygen isotope stage (MIS) 3 or 5 highstands.Ages and rates of uplift of the first emergent terrace vary systematically from west (younger and higher) to east (older and lower). The first emergent marine terraces in the westernmost SBFB are approximately 45 ka (MIS 3), and the rate of local surface uplift is ∼2 m/k.y. In the central part of the belt, first emergent terraces date to 60–70 ka (MIS 5), and uplift rates decrease to ∼1.2 m/k.y. First emergent marine terraces preserved in the easternmost fold belt range from 70 ka to 105 ka (MIS 5), with rates of local surface uplift of ∼0.5 m/k.y. Lower rates of uplift in the eastern end of the fold belt result from the MIS 5 terrace being tilted down into the Carpinteria syncline. Rates of vertical uplift in the western end of the fold belt are about six times higher than previously reported, suggesting the seismic hazard is also greater. 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