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

Published online by Cambridge University Press:  12 May 2004

John W. Sheraton ,
Robert J. Tingey ,
Lance P. Black  and
Robin L. Oliver
John W. Sheraton
Affiliation:
Australian Geological Survey Organisation, PO Box 378, Canberra City, ACT 2601, Australia
Robert J. Tingey
Affiliation:
Australian Geological Survey Organisation, PO Box 378, Canberra City, ACT 2601, Australia
Lance P. Black
Affiliation:
Australian Geological Survey Organisation, PO Box 378, Canberra City, ACT 2601, Australia
Robin L. Oliver
Affiliation:
Department of Geology and Geophysics, University of Adelaide, PO Box 498, Adelaide, SA 5001, Australia
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Abstract

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. Peak metamorphism (M1) (at about 750-800°C and 5-6kb) occurred 1190 ±15 Ma ago (U-Pb zircon age), and was accompanied by the first of three ductile deformations (D1). Emplacement of voluminous, mainly mantle-derived plutonic rocks, ranging from gabbro, through quartz monzogabbro and quartz monzodiorite, to granite, followed between 1170 (during D3) 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.

Keywords

Proterozoicgranulite-facies metamorphismplutonic rocksmafic dykesAntarctica-Australia correlations
Type
Papers—Earth Sciences and Glaciology
Information
Antarctic Science , Volume 5 , Issue 1 , March 1993 , pp. 85 - 102
Copyright
© Antarctic Science Ltd 1993

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