Geological and palaeomagnetic significance of the Kulgera Dyke Swarm, Musgrave Block, NT, Australia

A. Camacho*, B. Simons, P. W. Schmidt

*Corresponding author for this work

    Research output: Contribution to journalArticle

    39 Citations (Scopus)

    Abstract

    b The Kulgera Dyke Swarm consists of olivine tholeiites which have intruded late Proterozoic transitional‐granulite gneisses and granites of the eastern Musgrave Block, in central Australia. Preliminary Rb/Sr results suggest that the dolerites were emplaced at 1054 ± 14 Ma. In addition, a Rb/Sr age of 1060 ± 10 Ma on a biotite from a pegmatite indicates thermal resetting of the country rock minerals during dyke emplacement. Palaeomagnetic investigations of the dykes yield a primary thermoremanent magnetization direction corresponding to a palaeomagnetic pole at 17d̀S, 266d̀E (A95= 12d̀). In addition to this primary magnetization, an overprint component was present in many of the samples, providing a palaeomagnetic pole at 30d̀S, 138d̀E (A95= 24d̀), which is similar to previous results from other central Australian rocks affected by the Alice Springs Orogeny. The results extend the area of influence of the Carboniferous Alice Springs Orogeny southward into the Musgrave Block. Further, the results provide no evidence for an earlier, Late Proterozoic, Petermann Orogeny affecting the Musgrave Block in the Kulgera region. However, the possibility that a Petermann Orogeny thermal overprint has been erased by the Alice Springs Orogeny cannot be dismissed.

    Original languageEnglish
    Pages (from-to)37-45
    Number of pages9
    JournalGeophysical Journal International
    Volume107
    Issue number1
    DOIs
    Publication statusPublished - 1991

    Keywords

    • Alice Springs Orogeny
    • Musgrave Block
    • overprint
    • palaeomagnetism
    • Proterozoic Dyke Swarm
    • Rb‐Sr chronology

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