• Login
    About WHOAS
    View Item 
    •   WHOAS Home
    • Woods Hole Oceanographic Institution
    • Academic Programs
    • WHOI Theses
    • View Item
    •   WHOAS Home
    • Woods Hole Oceanographic Institution
    • Academic Programs
    • WHOI Theses
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of WHOASCommunities & CollectionsBy Issue DateAuthorsTitlesKeywordsThis CollectionBy Issue DateAuthorsTitlesKeywords

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Petrologic and microstructural constraints on focused melt transport in dunites and the rheology of the shallow mantle

    Thumbnail
    View/Open
    Braun_Thesis (12.16Mb)
    Date
    2004-06
    Author
    Braun, Michael Geoffrey  Concept link
    Metadata
    Show full item record
    Citable URI
    https://hdl.handle.net/1912/1856
    Location
    Oman ophiolite
    DOI
    10.1575/1912/1856
    Keyword
     Mid-ocean ridges; Mantle; Microstructure 
    Abstract
    Observations at mid-ocean ridges indicate that magmas are focused to the ridge axis by a network of porous dunites in near chemical isolation. This thesis investigates several of the outstanding questions regarding the mechanisms of melt transport and its effects on the shallow mantle. Chapter 1 details the current understanding of melt migration from observations at mid-ocean ridges and ophiolites. Chapter 2 uses the size distribution and abundance of dunites measured in the Oman ophiolite to place limits on the potential mechanisms by which dunites form and subsequently estimate the flux of chemically unequilbrated melt which a network of dunites can supply. Chapter 3 characterizes the chemical composition of dunites and harzburgites from Oman to further constrain the process by which dunites form and relates the observed trends within dunites to variations in the time-integrated meltrock ratio. Chapter 4 examines the microstructures of peridotites in Oman to constrain the deformation mechanisms which determine the viscosity of shallow mantle. Chapter 5 is a numerical investigation of advection beneath ridges incorporating the rheology inferred from the observed microstructures. Chapter 6 integrates the conclusions of the previous chapters, reevaluating the potential melt flux through dunites and constraining the permeabilty of the shallow mantle.
    Description
    Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2004
    Collections
    • Geology and Geophysics (G&G)
    • WHOI Theses
    Suggested Citation
    Thesis: Braun, Michael Geoffrey, "Petrologic and microstructural constraints on focused melt transport in dunites and the rheology of the shallow mantle", 2004-06, DOI:10.1575/1912/1856, https://hdl.handle.net/1912/1856
     

    Related items

    Showing items related by title, author, creator and subject.

    • Thumbnail

      Oceanic microstructure observed near Bermuda using a towed sensor 

      Magnell, Bruce Arthur (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1973-06)
      Many hypotheses have been advanced to explain the formation of mixed layers in the ocean; the salt finger type of double-diffusive convection, in particular, has received much attention. Because of their uniquely ordered ...
    • Thumbnail

      Mantle plume-midocean ridge interaction : geophysical observations and mantle dynamics 

      Ito, Garrett T. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-09)
      We analyze bathymetric and gravity anomalies at five plume-ridge systems to constrain crustal and mantle density structure at these prominent oceanic features. Numerical models are then used to explore the physical ...
    • Thumbnail

      Fine- and microstructure observations at Fieberling Guyot : R/V New Horizon cruise report 

      Montgomery, Ellyn T.; Toole, John M. (Woods Hole Oceanographic Institution, 1993-11)
      This report describes fine- and microstructure profile data taken on a cruise to Fieberling Guyot, a seamount in the northeast subtropical Pacific Ocean. The work performed at sea, instruments used, data return and ...
    All Items in WHOAS are protected by original copyright, with all rights reserved, unless otherwise indicated. WHOAS also supports the use of the Creative Commons licenses for original content.
    A service of the MBLWHOI Library | About WHOAS
    Contact Us | Send Feedback | Privacy Policy
    Core Trust Logo