Quaternary faulting in the southern Mississippi embayment and implications for tectonics and seismicity in an intraplate setting

Abstract

Research Article| November 01, 2000 Quaternary faulting in the southern Mississippi embayment and implications for tectonics and seismicity in an intraplate setting Randel Tom Cox; Randel Tom Cox 1Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Search for other works by this author on: GSW Google Scholar Roy B. Van Arsdale; Roy B. Van Arsdale 1Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Search for other works by this author on: GSW Google Scholar James B. Harris; James B. Harris 2Department of Geology, Millsaps College, Jackson, Mississippi 39210, USA Search for other works by this author on: GSW Google Scholar Steven L. Forman; Steven L. Forman 3Department of Earth and Environmental Science, University of Illinois, Chicago, Illinois 60607-2279, USA Search for other works by this author on: GSW Google Scholar William Beard; William Beard 4Department of Geology, Millsaps College, Jackson, Mississippi 39210, USA Search for other works by this author on: GSW Google Scholar Joseph Galluzzi Joseph Galluzzi 5Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Randel Tom Cox 1Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Roy B. Van Arsdale 1Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA James B. Harris 2Department of Geology, Millsaps College, Jackson, Mississippi 39210, USA Steven L. Forman 3Department of Earth and Environmental Science, University of Illinois, Chicago, Illinois 60607-2279, USA William Beard 4Department of Geology, Millsaps College, Jackson, Mississippi 39210, USA Joseph Galluzzi 5Department of Geological Sciences, University of Memphis, Memphis, Tennessee 38152, USA Publisher: Geological Society of America Received: 12 Jul 1999 Revision Received: 02 Mar 2000 Accepted: 15 Mar 2000 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2000) 112 (11): 1724–1735. https://doi.org/10.1130/0016-7606(2000)112<1724:QFITSM>2.0.CO;2 Article history Received: 12 Jul 1999 Revision Received: 02 Mar 2000 Accepted: 15 Mar 2000 First Online: 01 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 Randel Tom Cox, Roy B. Van Arsdale, James B. Harris, Steven L. Forman, William Beard, Joseph Galluzzi; Quaternary faulting in the southern Mississippi embayment and implications for tectonics and seismicity in an intraplate setting. GSA Bulletin 2000;; 112 (11): 1724–1735. doi: https://doi.org/10.1130/0016-7606(2000)112<1724:QFITSM>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 The recently recognized Saline River fault zone in the southwestern Mississippi embayment (strike = 135°) is characterized by moderate historic seismicity. We document paleoseismicity (possibly strong) on the Saline River fault zone that is outside the known region of neotectonism in the northern embayment. Six surface faults were excavated within the Saline River fault zone, and all faults displace marine Eocene units and fluvial Pliocene–Pleistocene units; five show post-Wisconsin loess movement (thermoluminescence [TL] age = 23.6 ± 3 ka), and three deform middle to late Holocene eolian silt (TL age = 5.1 ± 0.6 ka and 3.6 ± 0.5 ka) as fault-tip flexures. Along the principal excavated fault, fault-plane braiding and plunging drag folding suggest a strong component of left slip, and subsidiary faults show both normal and reverse displacement (<1m) of Pliocene−Pleistocene, Wisconsin, and Holocene units. We interpret these faults as components of a left-slip flower structure. A shallow seismic reflection profile acquired across the principal fault and a subsidiary fault shows Eocene stratigraphy separated in a reverse sense below 120 m depth and separated in a normal sense above 120 m, supporting a strike-slip interpretation. In addition, the only focal plane mechanism available in the area indicates left slip with a small reverse component.We conclude that the Saline River fault zone is a Paleozoic–Mesozoic basement fault zone reactivated as a left-slip system in a Quaternary east-west compressive stress field. Field evidence suggests that earthquakes with several meters of strike slip may be characteristic, and the width of a liquefaction field on the Saline River fault zone suggests an event of magnitude 5.5–6. Considering a similarity of strike and sense of Holocene movements of the Meers fault of southern Oklahoma and of the Saline River fault zone, there may be additional active fault zones that pose seismic hazards concealed by sediments in southern North America. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.