Melt transport from the mantle to the crust-uranium-series Isotopes

Simon P. Turner*, Bernard Bourdon

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

    11 Citations (Scopus)

    Abstract

    Once melting commences within the Earth's mantle, melt movement commences by porous flow. Whether or not the entire path to the surface occurs via porous flow or whether channeled flow takes over is not well understood. Since channeled flow will be much faster than porous flow, time scale information provides one of the most powerful means of distinguishing the mechanism involved. U-series isotopes are the principle source of this time scale information. Studies of 238U-230Th and 235U-231Pa disequilibria in mid-ocean ridge, ocean island and island arc basalts all place minimum constraints on ascent rates of 1-20 m/yr. 226Ra-230Th disequilibria in island arc basalts (IAB) arguably provide the most stringent constraint suggesting ascent rates of 70 m/yr. This requires channeled melt transport for the majority of source to surface path. It remains possible that 210Pb disequilbria are a melting signature and if so this would require melt ascent rates of km/yr. Such estimates are consistent with available seismic and experimental constraints that melt transport is in general fast.

    Original languageEnglish
    Title of host publicationTimescales of Magmatic Processes
    Subtitle of host publicationFrom Core to Atmosphere
    EditorsAnthony Dosseto, Simon P. Turner, James A. Van Orman
    Place of PublicationChichester, West Sussex, UK
    PublisherJohn Wiley & Sons
    Pages102-115
    Number of pages14
    ISBN (Electronic)9781444328509
    ISBN (Print)9781444332605
    DOIs
    Publication statusPublished - 30 Nov 2010

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