Magma cooling and differentiation - uranium-series isotopes

Anthony Dosseto*, Simon P. Turner

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingChapter

    4 Citations (Scopus)

    Abstract

    Timescales of magma cooling and differentiation can be quantified by measuring and modelling the composition of uranium-series (U-series) isotopes in crystals and whole rock samples. The U-series isotope composition of crystals yields a wide range of timescales: from a few tens of years to several hundred thousand years. Magma differentiation is inferred to be generally rapid (a few 1,000 years) at mid-ocean ridges and oceanic islands compared to island, continental arcs and intra-continental volcanic centres (1,000 to several 100,000 years). For large volume, highly silicic rocks (dacites, rhyolites), timescales of differentiation 100,000 years are generally inferred, reflecting the time required to heat up and assimilate the crust. U-series timescale information can be used to distinguish between different models for magma differentiation. For example, a model of frequent magma recharge combined with crustal assimilation seems to best explain U-series isotope data in many instances (and is probably the most realistic physical model). It is shown that, once the thermal regime that allows melting of the country rock is met (often requiring hundreds of thousands years), it takes only a few 1,000 years to produce highly silicic compositions.

    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; Hoboken, NJ
    PublisherWiley-Blackwell, Wiley
    Pages160-180
    Number of pages21
    ISBN (Electronic)9781444348262
    ISBN (Print)9781444332605, 9781444332612
    DOIs
    Publication statusPublished - Nov 2010

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