Tracking continental-scale modification of the Earth's mantle using zircon megacrysts

J. Woodhead*, J. Hergt, A. Giuliani, D. Phillips, R. Maas

*Corresponding author for this work

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    26 Citations (Scopus)
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    Abstract

    Metasomatism, the chemical alteration of rocks by a variety of melts and fluids, has formed a key concept in studies of the Earth's mantle for decades. Metasomatic effects are often inferred to be far-reaching and yet the evidence for their occurrence is usually based upon individual hand specimens or suites of rocks that display considerable heterogeneity. In rare cases, however, we are offered insights into larger-scale chemical modifications that occur in the mantle. Here we utilise the Lu-Hf systematics of zircon megacrysts erupted in kimberlite magmas to discern two temporally and compositionally discrete metasomatic events in the mantle beneath southern Africa, each having an influence extending over an area exceeding one million km2. These data provide unambiguous evidence for metasomatic processes operating at continental scales and seemingly unperturbed by the age and composition of the local lithospheric mantle. The most recent of these events may be associated with the major Jurassic-Karoo magmatism in southern Africa.

    Original languageEnglish
    Pages (from-to)1-6
    Number of pages6
    JournalGeochemical Perspectives Letters
    Volume4
    DOIs
    Publication statusPublished - 10 Jul 2017

    Bibliographical note

    Copyright 2017 European Association of Geochemistry. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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