Naturaliste Plateau, offshore western Australia: A submarine window into Gondwana assembly and breakup

Jacqueline A. Halpin*, Anthony J. Crawford, Nicholas G. Direen, Millard F. Coffin, Caroline J. Forbes, Irina Borissova

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    50 Citations (Scopus)

    Abstract

    The origin of the submarine Naturaliste Plateau off the southwestern coast of Australia is controversial; previous work supports both oceanic and continental affinities for the basement to volcanic and sedimentary sequences. We report the first evidence of reworked Mesoproterozoic (ca. 1230-1190 Ma) continental crust, based on laser ablation-inductively coupled plasma-mass spectrometry analysis of zircons from granite and orthogneiss samples dredged from the southern margin of the plateau. Thermobarometry of peak metamorphic minerals and electron microprobe chemical dating of monazite reveal that these igneous rocks were metamorphosed to ∼700 °C and ∼6.5 kbar during the Cambrian Pinjarra Orogeny at ca. 515 Ma. These data confirm a continental origin for a significant swathe of the southern Naturaliste Plateau, and suggest that the protoliths may have affinities to Mesoproterozoic crust within the Albany-Fraser-Wilkes Orogen (Australia-Antarctica). The present Naturaliste Plateau basement beneath its volcanic carapace probably represents a middle- to lower-crustal extensional allochthon exhumed during Cretaceous hyperextensional breakup between Australia and Antarctica.

    Original languageEnglish
    Pages (from-to)807-810
    Number of pages4
    JournalGeology
    Volume36
    Issue number10
    DOIs
    Publication statusPublished - 2008

    Keywords

    • Extensional allochthon
    • Naturaliste Plateau
    • Pinjarra Orogen
    • U-Pb zircon ages
    • U-Th-Pb monazite ages

    Fingerprint

    Dive into the research topics of 'Naturaliste Plateau, offshore western Australia: A submarine window into Gondwana assembly and breakup'. Together they form a unique fingerprint.

    Cite this