Mantle rocks in East Antarctica

Stephen Foley, Alexandre V. Andronikov, Jacqueline A Halpin, Nathan Daczko, Dorrit Jacob

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

    9 Citations (Scopus)

    Abstract

    Only three localities of mantle xenoliths are known from all of East Antarctica, occurring at the Jetty Peninsula (Lambert–Amery Rift), Vestfold Hills and Gaussberg volcano. The latter two are spinel-facies peridotites, whereas the Jetty Peninsula rocks also include garnet-spinel lherzolites; all come from Indo-Antarctica. The mantle xenoliths of Jetty Peninsula and Vestfold Hills contain abundant geochemical and mineralogical evidence for multiple enrichment events that are attributed to infiltration of melts and their fluid products. Many of these episodes are spatially related to precursory activity along major trans-lithospheric structures that eventually led to the separation of India from Antarc-tica. Mantle rocks also occur at Schirmacher Oasis (Dronning Maud Land) and Haskard Highlands (Shackleton Ranges) as blocks tectonically emplaced in high-grade crustal rocks. These show varying degrees of alteration due to reaction with silicic crustal rocks or hydrous fluids: none correspond to unchanged mantle compositions. Geophysical surveys are our only information on the mantle lithosphere beneath the inland ice, and these can be used to infer the locations of thicker lithosphere probably related to cratons by southward extrapolation of coastal geological correlations. Intense local modification of the mantle lithosphere by melt infiltration and fluid movements may influence the large-scale images derived from geophysical data, and may be incorrectly interpreted as homogeneous compositions.
    Original languageEnglish
    Title of host publicationThe Geochemistry and Geophysics of the Antarctic Mantle
    EditorsRick Law
    Place of PublicationLondon, United Kingdom
    PublisherGeological Society of London
    Pages17-32
    Volume56
    ISBN (Print)978-1-78620-467-7
    DOIs
    Publication statusPublished - 2023

    Publication series

    Name
    Number1
    Volume56

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