Mechanism for retreating barriers to autogenically form periodic deposits on continental shelves

Abstract

Research Article| January 29, 2019 Mechanism for retreating barriers to autogenically form periodic deposits on continental shelves Daniel J. Ciarletta; Daniel J. Ciarletta 1Department of Earth and Environmental Studies, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, USA Search for other works by this author on: GSW Google Scholar J. Lorenzo-Trueba; J. Lorenzo-Trueba 1Department of Earth and Environmental Studies, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, USA Search for other works by this author on: GSW Google Scholar A.D. Ashton A.D. Ashton 2Geology and Geophysics Department, Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, USA Search for other works by this author on: GSW Google Scholar Geology (2019) 47 (3): 239–242. https://doi.org/10.1130/G45519.1 Article history received: 23 Aug 2018 rev-recd: 25 Dec 2018 accepted: 31 Dec 2018 first online: 29 Jan 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Daniel J. Ciarletta, J. Lorenzo-Trueba, A.D. Ashton; Mechanism for retreating barriers to autogenically form periodic deposits on continental shelves. Geology 2019;; 47 (3): 239–242. doi: https://doi.org/10.1130/G45519.1 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 SocietyGeology Search Advanced Search Abstract Relict barrier deposits preserved on the shelf seabed from barrier transgression are common features of passive, sandy margins, with multiple deposits occasionally found evenly spaced several to tens of kilometers apart. The formation of these deposits has typically been ascribed to allogenic overstepping processes, most commonly to episodes of rapid sea-level rise, although changes in topography or external sediment supply have also been invoked. Here, we present a mechanism whereby autogenic feedbacks between shoreface dynamics and the landward overwash of sediments can form regularly spaced shelf deposits even with constantly rising sea level. A simple morphodynamic model of barrier transgression exhibits a mode of periodic retreat whereby alternating episodes of translation and aggradation arise from internal dynamics, generating low-relief cross-shore deposits of barrier sediment with kilometer-scale spacing that increases for more gradual shelf slopes. Modeled barriers develop autogenic partial overstepping on shelf slopes with gradients between 1 and 3 m/km and for rates of sea-level rise between 1 and 18 mm/yr. Deposits produced by the model correlate with field observations of overstepped barriers from around the world, sharing an inverse relationship between shelf slope and spacing (wavelength). This result suggests that discrete remnant barrier deposits may not be exclusively indicative of changes in external forcing and that currently stable barrier islands may be susceptible to rapid behavioral transitions. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.