Geology of the Bunger Hills area, Antarctica: implications for Gondwana correlations

John W. Sheraton, Robert J. Tingey, Lance P. Black, Robin L. Oliver
1993 Antarctic Science  
The Bunger Hills area of the East Antarctic Shield consists of granulite-facies felsic orthogneiss, with subordinate paragneiss and mafic granulite. The igneous precursors of granodioritic orthogneiss were emplaced 1500-1700 Ma ago, and late Archaean (2640 Ma) tonalitic orthogneiss occurs in the nearby Obruchev Hills. Peakmetamorphism (MI) (at about 750-800°C and 5-6kb) occurred 1190 2 15 Ma ago (U-Pb zircon age), and was accompanied by the first of three ductile deformations (DJ Emplacement of
more » ... (DJ Emplacement of voluminous, mainly mantle-derived plutonic rocks, ranging from gabbro, through quartz monzogabbro and quartz monzodiorite, to granite, followed between 1170 (during DJ and 1150 Ma. Intrusion of abundant dolerite dykes of four chemically distinct suites at about 1140 Ma was associated with shear zone formation, indicating at least limited uplift; all subsequent deformation was of brittle-ductile type. Alkaline mafic dykes were emplaced 500 Ma ago. Marked geochronological similarities with the Albany Mobile Belt of Western Australia suggest that high-grade metamorphism occurred during collision between the Archaean Yilgarn Craton of Australia and the East Antarctic Shield about 1200 Ma ago.
doi:10.1017/s0954102093000112 fatcat:hs6uigqbxzacto73ql7dqfvhum