Magnetotelluric constraints on subduction polarity

reversing reconstruction models for Proterozoic Australia

Kate Selway*, Martin Hand, Graham S. Heinson, Justin Payne

*Corresponding author for this work

    Research output: Contribution to journalArticle

    36 Citations (Scopus)

    Abstract

    Two-dimensional, lithospheric-scale magnetotelluric imaging in the central Australian Proterozoic has constrained the large-scale architecture of terrane assembly during Paleoproterozoic accretion and collision. The comparatively conductive North Australian craton, consisting of rocks between similar to 2500 and 1730 Ma in age, has been imaged to extend for 150 km under the 1690-1620 Ma Warumpi Province, which forms part of a large, comparatively juvenile terrane in central-southern Australia. Collision between the North Australia craton and Warumpi Province occurred ca. 1640 Ma. The boundary between these domains is modeled to be subvertical at crustal scale, but dips south at similar to 45 degrees in the mantle to depths of 150 km. We interpret this geometry to reflect lithospheric-scale underthrusting of the North Australian craton beneath the Warumpi Province, and suggest that it provides a first-order constraint on subduction polarity during collision ca. 1640 Ma. In contrast, most contemporary models for the evolution of Paleoproterozoic Australia propose that the North Australian craton was located on the overriding plate of a long-lived (ca. 1800-1550 Ma) north-directed subduction system. The polarity of these models is not consistent with the lithospheric-scale geophysical architecture.

    Original languageEnglish
    Pages (from-to)799-802
    Number of pages4
    JournalGeology
    Volume37
    Issue number9
    DOIs
    Publication statusPublished - Sep 2009

    Keywords

    • ARUNTA-INLIER
    • ISOTOPIC SYSTEMATICS
    • CRUSTAL DEVELOPMENT
    • TECTONIC EVOLUTION
    • MUSGRAVE BLOCK
    • LITHOSPHERE
    • GRANULITES
    • GRANITES
    • TENSOR
    • NORTH

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