Origin of the Australian–Antarctic Discordance from an ancient slab and mantle wedge
Published:January 01, 2003
M. GURNIS, R. D. MÜLLER, 2003. "Origin of the Australian–Antarctic Discordance from an ancient slab and mantle wedge", Evolution and Dynamics of the Australian Plate, R.R. Hillis, R.D. Müller
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A variety of evidence has suggested that the enigmatic Australian–Antarctic Discordance is caused by a cold zone beneath the present-day South East Indian Ridge south of Australia. We show that the present position of the subduction zone which surrounded Gondwanaland until the Mesozoic is within a few hundred kilometres of the Australian–Antarctic Discordance. Beneath the Australian–Antarctic Discordance, tomographic inversions show a north-south-trending seismic anomaly with a higher than average shear velocity in the lower mantle and a prominent, nearly circular, high-velocity anomaly within the transition zone. These seismic inversions are consistent with the predictions of three-dimensional models of mantle convection...