Sunrise Hill unconformity: A newly discovered regional hiatus between Archaean granites and greenstones in the northeastern Pilbara Craton |
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| Authors: | P R Dawes R H Smithies J Centofanti D C Podmore |
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| Institution: | 1. Geological Survey of Western Australia , 100 Plain Street, East Perth, WA, 6004, Australia;2. Geological Survey of Greenland , ?stervoldgade 10, Copenhagen K, Denmark;3. Geological Survey of Western Australia , 100 Plain Street, East Perth, WA, 6004, Australia;4. BHP Iron Ore , PO Box 231, Port Hedland, WA, 6721, Australia |
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| Abstract: | Contacts between Archaean granites and greenstones in the northeastern part of the Pilbara Craton have been described as intrusive and tectonic. New field observations in the Shay Gap region demonstrate that greenstones of the Gorge Creek Group unconformably overlie the Muccan and Warrawagine batholiths. Regionally, the unconformity is marked by a persistent but relatively thin basal clastic sequence, locally with a granite boulder conglomerate, overlain by ore‐bearing banded iron‐formation, fine‐grained clastic rocks and chert. The granite basement is dated at 3443 ± 6 Ma. The precise age of the hiatus is unknown but its maximum effect might have been the removal of a substantial thickness of Early to Middle Archaean strata. |
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| Keywords: | Archaean granite banded iron‐formation greenstone Pilbara Craton unconformity |
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