Skip to content
University of Maryland LibrariesDigital Repository at the University of Maryland
    • Login
    View Item 
    •   DRUM
    • Theses and Dissertations from UMD
    • UMD Theses and Dissertations
    • View Item
    •   DRUM
    • Theses and Dissertations from UMD
    • UMD Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Highly Siderophile Element and Tungsten Systematics of Hawaiian Picrites

    Thumbnail
    View/Open
    Ireland_umd_0117E_10759.pdf (2.653Mb)
    No. of downloads: 910

    Date
    2009
    Author
    Ireland, Thomas James
    Advisor
    Walker, Richard J
    Metadata
    Show full item record
    Abstract
    A suite of Hawaiian picrites (MgO > 13 wt.%), and associated basalts, that represent some of the most primitive melts from the Hawaiian mantle source regions were analyzed for their W, highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd and Re) and <super>186</super>Os-<super>187</super>Os isotope systematics. These picritic samples are among the most primitive samples produced from the Hawaiian main-shield stage volcanoes. As such, they may preserve considerable information about the mantle source regions from which they were derived. Hawaii is of particular interest because there is geochemical and geophysical evidence that suggest that the Hawaiian plume may originate at the core-mantle boundary. If any outer core material is incorporated into plume lavas, it could carry important geochemical information. The primary goal of this study is to improve our understanding of the processes and materials that may affect the mantle source regions of the Hawaiian volcanoes. Abundances of HSE and W, as well as Os isotopes, are useful tools for evaluating the mantle source regions of ocean island basalts because their absolute and relative abundances may be affected by various mantle processes, including the recycling of oceanic crust and sediment, mantle metasomatism, and other forms of crystal-liquid fractionation. In addition, these elements may be suitable for addressing the question of core-mantle interaction, because the core is highly concentrated in both the moderately siderophile and highly siderophile elements, and may have a distinct Os isotopic composition relative to the mantle. The collected data imply that W abundances in the Hawaiian mantle sources are similar for all volcanic centers, and enriched relative to depleted MORB mantle. This suggests that W may be controlled by a primary source component that is less depleted in incompatible elements than the depleted mantle. HSE abundances in the picrites are controlled predominantly by crystal-liquid fractionation processes, and may reflect the presence of residual sulfides in the mantle sources. Lastly, the <super>187</super>Os/<super>188</super>Os variations are consistent with some proportion of a recycled oceanic crust component; however, variations in <super>186</super>Os/<super>188</super>Os require another process, such as the incorporation of variable Pt-enriched base-metal sulfides, or mixing with an <super>186</super>Os-<super>187</super>Os enriched reservoir.
    URI
    http://hdl.handle.net/1903/9831
    Collections
    • Geology Theses and Dissertations
    • UMD Theses and Dissertations

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility
     

     

    Browse

    All of DRUMCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister
    Pages
    About DRUMAbout Download Statistics

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility