• 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

    Syn-eruptive degassing of a single submarine lava flow : constraints on MORB CO2 variability, vesiculation, and eruption dynamics

    Thumbnail
    View/Open
    Nakata_thesis.pdf (7.419Mb)
    Date
    2010-06
    Author
    Nakata, Dorene S.  Concept link
    Metadata
    Show full item record
    Citable URI
    https://hdl.handle.net/1912/3933
    Location
    East Pacific Rise
    DOI
    10.1575/1912/3933
    Keyword
     Mid-ocean ridges; Seawater; Carbon dioxide content; Atlantis (Ship : 1996-) Cruise AT15-17 
    Abstract
    Mid-ocean ridge basalts (MORBs) exhibit a wide range of CO2 concentrations, reflecting saturation to supersaturation (and rarely undersaturation) relative to their emplacement depths. In this study, we explore the mechanisms of CO2 degassing and the implications this has for estimating the advance rates and durations of seafloor eruptions. We present dissolved volatile concentrations (mainly of CO2 and H2O) and vesicle size distributions (VSDs) for a unique suite of MORB glasses collected at the East Pacific Rise, ~9° 50′ N. These MORB glasses were collected at ~200 m intervals along an across-axis track over a single flow pathway within the recently emplaced 2005-06 eruption boundaries; systematic sample collection provides one of the first opportunities to characterize intra-flow geochemical and physical evolution during a single eruption at a fast-spreading ridge. Compared to measurements of MORB volatiles globally, dissolved H2O concentrations are relatively uniform (0.10 - 0.16 weight percent), whereas dissolved CO2 contents exhibit a range of concentrations (154 - 278 ppm) and decrease with distance from the EPR axis (i.e., eruptive vent). Ion microprobe analyses of dissolved volatiles within the MORB glasses suggest that the magma erupted supersaturated (pressure equilibrium with 920 - 1224 mbsf) and in near-equilibrium with the melt lens of the axial magma chamber (~1250 - 1500 mbsf), and degassed to near equilibrium (299 - 447 mbsf) with seafloor depths over the length of the flow. The decrease in CO2 concentrations spans nearly the full range of dissolved CO2 contents observed at the EPR and shows that the varying degrees of volatile saturation that have been observed in other MORB sample suites may be explained by degassing during emplacement. Vesicularity (0.1 - 1.2%) increases with decreasing dissolved CO2 concentrations. We use vesicle size distributions (VSDs)—vesicle sizes and number densities—to quantify the physical evolution of the CO2 degassing process. VSDs suggest that diffusion of CO2 into preexisting vesicles, and not nucleation of new vesicles, is the dominant mechanism of increasing CO2 in the vapor phase. We also use VSDs, along with estimates of vesicle growth rates, to constrain emplacement time of the 2005-06 eruption to <~24 hours and to resolve variations in advance rate with downflow distance.
    Description
    Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2010
    Collections
    • Geology and Geophysics (G&G)
    • WHOI Theses
    Suggested Citation
    Thesis: Nakata, Dorene S., "Syn-eruptive degassing of a single submarine lava flow : constraints on MORB CO2 variability, vesiculation, and eruption dynamics", 2010-06, DOI:10.1575/1912/3933, https://hdl.handle.net/1912/3933
     

    Related items

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

    • Thumbnail

      The influence of magma supply and eruptive processes on axial morphology, crustal construction and magma chambers 

      Hooft, Emilie E. E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-12)
      Two-thirds of the surface of the Earth is created at mid-ocean ridges where magmas rise from the mantle and cool to form the oceanic crust. The objective of this Thesis is to examine the influence of magma supply and ...
    • Thumbnail

      Reproductive traits of pioneer gastropod species colonizing deep-sea hydrothermal vents after an eruption 

      Bayer, Skylar R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2011-06)
      The colonization dynamics and life histories of pioneer species are vital components in understanding the early succession of nascent hydrothermal vents. The reproductive ecology of pioneer species at deep-sea hydrothermal ...
    • Thumbnail

      Eruptions at Lone Star Geyser, Yellowstone National Park, USA: 1. Energetics and eruption dynamics 

      Karlstrom, Leif; Hurwitz, Shaul; Sohn, Robert A.; Vandemeulebrouck, Jean; Murphy, Fred; Rudolph, Maxwell L.; Johnston, Malcolm J. S.; Manga, Michael; McCleskey, R. Blaine (John Wiley & Sons, 2013-08-13)
      Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from a 4 day experiment at Lone Star Geyser in Yellowstone National Park, USA. We simultaneously measured water discharge, ...
    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