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Crustal velocity and sediment thickness asymmetries along and between the conjugate Australian-Antarctic margins

conference contribution
posted on 2023-05-23, 07:34 authored by Joanne WhittakerJoanne Whittaker, Goncharov, A, Williams, SE, Muller, RD
The Australian-Antarctic conjugate margins are remarkably symmetric in comparison to other magma-poor rifted continental margins, particularly in the central Great Australian Bight section. Here, we use two datasets derived from seismic refraction data to investigate the pre-rift crustal structure of the conjugate Australian- Antarctic margins. We analyse two datasets for the conjugate Australian-Antarctic margins, (i) seismic velocity data derived from a synthesis of seismic refraction and sonobuoy data, and (ii) estimates of total sediment thickness from seismic refraction data calibrated against stacking-derived seismic velocities from seismic reflection profiles along each margin. Using a novel approach involving plate reconstruction and 3D visualistion we utilize these datasets to map the 3D lithospheric structure of the Australian- Antarctic margins. Our approach enables accurate juxtaposition of the Australian-Antarctic conjugate margins at the approximate time of breakup (~83 Ma). We find that the distribution of sediment along and across the conjugate Australian-Antarctic margins is highly asymmetric and that observed asymmetries in crustal structure are predominantly due to the patterns of sediment loading. Our results also indicate that total sediment thicknesses have been significantly underestimated from seismic reflection profile data for large sections of both margins. Underestimations of total sediment thickness appear particularly severe on the Antarctic margin. A significant insight this analysis provides is that the velocity information from seismic refraction data has been grossly under-utilised.


Publication title

Eastern Australasian Basins Symposium IV


Special Publication


Mares, T.




Institute for Marine and Antarctic Studies


Petroleum Exploration Society of Australia

Place of publication


Event title

Eastern Australasian Basins Symposium IV

Event Venue

Brisbane, QLD

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Date of Event (End Date)


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Copyright 2012 The Authors - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s).

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Expanding knowledge in the earth sciences

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