SHRIMP U–Pb zircon dating of Grenville-age events in the western part of the Musgrave Block, central Australia |
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| Authors: | White Clarke & Nelson |
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| Institution: | School of Earth Sciences, Macquarie University, Sydney, NSW 2109, Australia (email:;), , School of Geosciences, University of Sydney, Sydney, NSW 2006, Australia,;Geological Survey of Western Australia, 100 Plain St, East Perth, WA 6004, Australia |
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| Abstract: | Shrimp U–Pb zircon dating of structurally constrained felsic orthogneiss samples in the western Musgrave Block has been used to delineate discrete magmatic and metamorphic events at c . 1300 and c . 1200 Ma. The dating of pre-D1 and post-D1 felsic orthogneiss constrains D1 to have occurred at 1312±16 to 1324±4 Ma. This is the first geochronological study to identify such a metamorphic and deformation event in the Musgrave Block. D1 was accompanied by a major magmatic event involving the emplacement of voluminous felsic orthogneiss between 1296 and 1324 Ma. Zircon overgrowths on numerous igneous zircon cores give a consistent age of c . 1200 Ma, reflecting zircon growth during a second high-grade metamorphic event (D2). This c . 1200 Ma metamorphic event was followed by the intrusion of a c . 1190 Ma megacrystic granite. The c . 1300 and c . 1200 Ma events in the Musgrave Block can be tentatively correlated with metamorphic events in the Albany-Fraser Orogen, and the Windmill Islands and Bunger Hills in east Antarctica. A major continuous Grenville-age orogenic belt joining these areas may have represented a plate boundary between the pre-Rodinian proto-Australian continent and proto-Antarctica during the formation of Rodinia in the Mesoproterozoic. |
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| Keywords: | granulite facies Grenville Orogen Musgrave Block orogeny SHRIMP U–Pb zircon dates |
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