Untying the Kibaran knot: A reassessment of Mesoproterozoic correlations in southern Africa based on SHRIMP U-Pb data from the Irumide belt

Bert De Waele, Michael T D Wingate, Ian C W Fitzsimons, Benjamin S E Mapani

    Research output: Contribution to journalArticle

    83 Citations (Scopus)

    Abstract

    The Irumide belt is part of a network of late Mesoproterozoic Kibaran-age orogens in south-central Africa. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon ages for gneisses, migmatites, and granitoids indicate that peak Irumide metamorphism was ca. 1020 Ma and that this was associated with widespread granitic magmatism at 1050-950 Ma. Pre-Irumide protoliths are dominated by 1650-1519 Ma granitic gneisses. These data provide the first robust constraint on the timing of Irumide tectonism and show that previous estimates of ca. 1350 and 1100 Ma are incorrect, thereby negating previously proposed correlations of the Irumide belt with nearby Kibaran-aged tectonism. The correlation between the Irumide belt and Choma-Kalomo block of southern Zambia has had a major influence on models for the tectonic assembly of southern Africa because it required that the intervening Neoproterozoic Zambezi belt was intracratonic and associated with minimal horizontal displacements. Our data indicate that both terranes have distinct histories, consistent with lithologic and metamorphic evidence of Neoproterozoic ocean closure along the Zambezi belt. This implies that the Kalahari and Congo cratons assembled during the Neoproterozoic and not during Kibaran-age tectonism, as previously believed. This new outlook on regional African tectonics supports a configuration of the Rodinia supercontinent that places the Congo craton well away from the Kalahari craton ca. 1000 Ma.

    Original languageEnglish
    Pages (from-to)509-512
    Number of pages4
    JournalGeology
    Volume31
    Issue number6
    DOIs
    Publication statusPublished - Jun 2003

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    ion microprobe
    craton
    tectonics
    Rodinia
    supercontinent
    protolith
    magmatism
    terrane
    zircon
    metamorphism
    Southern Africa
    ocean
    history

    Cite this

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    title = "Untying the Kibaran knot: A reassessment of Mesoproterozoic correlations in southern Africa based on SHRIMP U-Pb data from the Irumide belt",
    abstract = "The Irumide belt is part of a network of late Mesoproterozoic Kibaran-age orogens in south-central Africa. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon ages for gneisses, migmatites, and granitoids indicate that peak Irumide metamorphism was ca. 1020 Ma and that this was associated with widespread granitic magmatism at 1050-950 Ma. Pre-Irumide protoliths are dominated by 1650-1519 Ma granitic gneisses. These data provide the first robust constraint on the timing of Irumide tectonism and show that previous estimates of ca. 1350 and 1100 Ma are incorrect, thereby negating previously proposed correlations of the Irumide belt with nearby Kibaran-aged tectonism. The correlation between the Irumide belt and Choma-Kalomo block of southern Zambia has had a major influence on models for the tectonic assembly of southern Africa because it required that the intervening Neoproterozoic Zambezi belt was intracratonic and associated with minimal horizontal displacements. Our data indicate that both terranes have distinct histories, consistent with lithologic and metamorphic evidence of Neoproterozoic ocean closure along the Zambezi belt. This implies that the Kalahari and Congo cratons assembled during the Neoproterozoic and not during Kibaran-age tectonism, as previously believed. This new outlook on regional African tectonics supports a configuration of the Rodinia supercontinent that places the Congo craton well away from the Kalahari craton ca. 1000 Ma.",
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    Untying the Kibaran knot : A reassessment of Mesoproterozoic correlations in southern Africa based on SHRIMP U-Pb data from the Irumide belt. / De Waele, Bert; Wingate, Michael T D; Fitzsimons, Ian C W; Mapani, Benjamin S E.

    In: Geology, Vol. 31, No. 6, 06.2003, p. 509-512.

    Research output: Contribution to journalArticle

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    T2 - A reassessment of Mesoproterozoic correlations in southern Africa based on SHRIMP U-Pb data from the Irumide belt

    AU - De Waele, Bert

    AU - Wingate, Michael T D

    AU - Fitzsimons, Ian C W

    AU - Mapani, Benjamin S E

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    KW - Mesoproterozoic

    KW - SHRIMP data

    KW - Southern Africa

    KW - Zambia

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