Authors / CoAuthors
Hollis, J.A. | Carson, C.J. | Glass, L.M.
Abstract
The Pine Creek Orogen located on the exposed northern periphery of the North Australian Craton, comprises a thick succession of variably metamorphosed Palaeoproterozoic siliciclastic and carbonate sedimentary and volcanic rocks, which were extensively intruded by mafic and granitic rocks. Exposed Neoarchaean basement is rare in the Pine Creek Orogen and the North Australian Craton in general. However, recent field mapping, in conjunction with new SHRIMP U-Pb zircon data for five granitic gneiss samples, have identified previously unrecognised Neoarchaean crystalline crust in the Nimbuwah Domain, the eastern-most region of the Pine Creek Orogen. Three samples from the Myra Falls and Caramal Inliers and from the Cobourg Peninsula have magmatic crystallisation ages in the range 2527-2510 Ma. An additional sample, from northeast Myra Falls Inlier, yielded a magmatic crystallisation age of 2671 - 3 Ma, the oldest exposed Archaean basement yet recognised in the North Australian Craton. These results are consistent with previously determined magmatic ages for known outcropping and subcropping crystalline basement some 200 km to the west. A fifth sample yielded a magmatic crystallisation age of 2640 - 4 Ma. The ca. 2670 and ca. 2640 Ma samples have ca. 2500 Ma metamorphic zircon rims, consistent with metamorphism during emplacement of the volumetrically dominant ca. 2530-2510 Ma granites and granitic gneisses. Neoarchaean zircon detritus, particularly in the ca. 2530-2510 Ma and ca. 2670-2640 Ma age span, are an almost ubiquitous feature of detrital zircon spectra of unconformably overlying metamorphosed Palaeoproterozoic strata of the Pine Creek Orogen, and of local post-tectonic Proterozoic sequences, consistent with this local provenance.
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nonGeographicDataset
eCat Id
68849
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Keywords
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- External PublicationScientific Journal Paper
- ( Theme )
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- geochronology
- ( Theme )
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- marine
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- AU-NT
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2009-01-01T00:00:00
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geoscientificInformation
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[-13.0, -12.0, 132.0, 133.5]
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