Extremely asymmetric magmatic accretion of oceanic crust at the ends of slow-spreading ridge segments

Abstract

Research Article| February 01, 2000 Extremely asymmetric magmatic accretion of oceanic crust at the ends of slow-spreading ridge segments Simon Allerton; Simon Allerton 1Department of Geology and Geophysics, University of Edinburgh, Edinburgh EH9 3JW, UK Search for other works by this author on: GSW Google Scholar Javier Escartín; Javier Escartín 1Department of Geology and Geophysics, University of Edinburgh, Edinburgh EH9 3JW, UK2Department of Geological Sciences, University of Durham, Durham DH1 3LE, UK Search for other works by this author on: GSW Google Scholar Roger C. Searle Roger C. Searle 2Department of Geological Sciences, University of Durham, Durham DH1 3LE, UK Search for other works by this author on: GSW Google Scholar Geology (2000) 28 (2): 179–182. https://doi.org/10.1130/0091-7613(2000)28<179:EAMAOO>2.0.CO;2 Article history received: 01 Jun 1999 rev-recd: 12 Oct 1999 accepted: 28 Oct 1999 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 Simon Allerton, Javier Escartín, Roger C. Searle; Extremely asymmetric magmatic accretion of oceanic crust at the ends of slow-spreading ridge segments. Geology 2000;; 28 (2): 179–182. doi: https://doi.org/10.1130/0091-7613(2000)28<179:EAMAOO>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 SocietyGeology Search Advanced Search Abstract We report the results of a deep-towed magnetic survey of part of a Mid-Atlantic Ridge spreading segment. Analysis of the magnetic reversals indicates that for the past 0.7 m.y., magmatic accretion at the end of the segment has been effectively one sided, with new crust being added only to the outside corner of the ridge offset (eastern flank), and not to the inside corner (western flank). Spreading on the inside corner was accommodated by significant displacement on a single, large fault. The area between the fault and the axial volcanic ridge was effectively a thin static sliver at the plate boundary during this process. In the short term, asymmetric magmatic accretion was probably accomplished by progressively shifting the axial volcanic ridge to a new location at the inside corner (western) edge of the old one. Asymmetric spreading is unlikely to be sustainable as a steady-state process. The termination of a period of asymmetric spreading may be achieved either by establishing a new axial volcanic ridge to a position on the outside corner (eastern) plate (thus isolating the old axial volcanic ridge on the inside-corner plate), or by simply arresting movement on the large fault, and reverting to symmetric spreading at the axial volcanic ridge. Highly asymmetric accretion may be a common process at slow-spreading segments, particularly near discontinuities. This asymmetry cannot be maintained for long periods, and may be directly linked to intervals of spreading by tectonic extension. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.