SHRIMP U–Pb zircon dating of Grenville‐age events in the western part of the Musgrave Block, central Australia

• Published in: Journal of Metamorphic Geology
• Main Authors: White, Clarke, Nelson
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1999
• Subjects: Antarc*; Antarctica; East Antarctica; Windmill Islands
• Online Access: http://dx.doi.org/10.1046/j.1525-1314.1999.00211.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1525-1314.1999.00211.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1525-1314.1999.00211.x

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‐D 1 and post‐D 1 felsic orthogneiss constrains D 1 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. D 1 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 (D 2 ). 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.