Authors / CoAuthors
Howard, K.E. | Hand, M. | Barovich, K. | Lambeck, A. | Belousova, E.A.
Abstract
New provenance data from Palaeoproterozoic and possible Archaean sedimentary units in the central eastern Gawler Craton forms part of a growing dataset suggesting that the Gawler Craton shares important basin formation and tectonic time lines with the adjacent Curnamona Province and the Isan Inlier in northern Australia. U-Pb dating of detrital zircons from the Eba Formation (previously mapped as Tarcoola Formation), yield exclusively Archaean ages (~2530-3300 Ma). This is consistent with whole rock Nd and zircon Hf isotopic data for the Eba Formation which have evolved compositions. Elsewhere in the eastern Gawler Craton, cover sequences historically considered to be Palaeoproterozoic in age also contain exclusively Neo and Meso Archaean aged detrital zircons (Reid et al, 2009 Econ. Geol.; Szpunar et al, 2007, SGTSG). The absence of Palaeoproterozoic detrital grains in several differently mapped sequences (including the Eba Formation) despite the proximity of voluminous Palaeoproterozoic rock units, suggests that the Eba Formation may be part of a Neo-Archaean or early Palaeoproterozoic cover sequence derived from erosion of a complex Archaean aged source region. The Labyrinth Formation unconformably overlies the Eba Quartzite, and contains rhyolitic units that constrain deposition to 1715 ± 9 Ma (Fanning et al., 2007; PIRSA Bulletin 55). This age is identical to the timing of deposition of the lower Willyama Supergroup in the adjacent Curnamona Province. Detrital zircon ages in the Labyrinth Formation range from NeoArchaean to Palaeoproterozoic, and are consistent with derivation from > 1715 Ma components of the Gawler Craton. Isotopic zircon Hf data and whole rock Nd data also suggest a source region with a mixed crustal evolution (-Nd -4.5 to -6), consistent with what is known about the Gawler Craton. Compared to the Lower Willyama Supergroup, the Labyrinth Formation has a source more obviously reconcilable with the Gawler Craton.
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nonGeographicDataset
eCat Id
69710
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- External PublicationAbstract
- ( Theme )
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- geochemistry
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- isotopes
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- geochronology
- ( Theme )
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- sedimentary basins
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- AU-QLD
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2009-10-23T00:00:00
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