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This paper develops a crustal model of the conjugate, oblique-slip continental margins of George V Land, east Antarctica, and the Otway Basin, southeast Australia, based on the interpretation of seismic and sample data.

This record is a report of the operations carried out during Geoscience Australia Survey 229 off the Australian Antarctic Territory from January-April 2002. The survey acquired deep-seismic and potential field data along 8600 km of profiles as a part of the Australian Antarctic and Southern Ocean Profiling Project.

This Record contains a shipboard interpretation of the data acquired on Geoscience Australia Survey 229 off the Australian Antarctic Territory from January-April 2002. The survey acquired deep-seismic and potential field data along 8600 km of profiles as part of the Australian Antarctic and Southern Profiling Project.

The Antarctic continental slope spans the depths from the shelf break (usually between 500-1000 m) to ~3000 m, is very steep, overlain by 'warm' Circumpolar Deep Water and life there is poorly studied. This study investigates whether life on Antarctica's continental slope is essentially an extension of the shelf or the deep-sea fauna, a transition zone between these or clearly distinct in its own right. Using data from several cruises to the Weddell and Scotia sea, including the ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonisation history and recent community patterns) I-III and BIOPEARL (BIOdiversity, Phylogeny, Evolution and Adaptive Radiation of Life in Antarctica) 1 and EASIZ II cruises as well as current data bases (SOMBASE, SCAR-MarBIN), we selected four different taxa (i.e. cheilostome bryozoans, isopod and ostracod crustaceans, and echinoid echinoderms) and two areas, the Weddell and the Scotia Sea, to examine faunal composition, richness and affinities. The answer has important ramifications to the link between physical oceanography and ecology, and the potential of the slope to act as a refuge and resupply zone to the shelf during glaciations (and therefore support or not glaciological reconstructions of ice sheets covering continental shelves).

Record documenting sources of gravity and magnetic data covering the Capel and Faust basins (Lord Howe Rise) and the processes applied to level the data.

Geological framework of the South Tasman Rise and East Tasman Plateau, Law of the Sea report

A Geoscience Australia multi-channel seismic reflection survey of the Bremer and Mentelle sub-basins in 2004 also deployed 30 sonobuoys. Ray-trace modelling of the acquired refraction data provided velocity profiles used to check stacking velocities for depth estimation. Comparison of the two datasets suggests that stacking velocities are a reasonably accurate proxy for sonic velocities down to 2 s twt, below which the ray coverage with present technology is insufficient to make an assessment. The sonobuoy data also provide constraints on identification of basement, in which velocities of 5-6 km/s range suggest a metasedimentary rather than granitic type lies beneath the Bremer sub-basin sediments.

An integrated interpretation of deep-seismic and potential field data from the conjugate, magma-poor, rifted margins of the Great Australian Bight, southern Australia, and central Wilkes Land, East Antarctica, shows that there is pronounced symmetry of structures in a 300 km-wide zone straddling the axis of final breakup.

New geophysical data acquired by Geoscience Australia during the Southwest Margins 2D seismic survey in 2008-09 has been used to interpret the tectonic and depositional history of the Mentelle Basin. The Mentelle Basin is a large, potentially prospective frontier basin located between the Yallingup Shelf and the Naturaliste Plateau. It comprises several shallow water depocentres (500-1500 m) in the east (eastern Mentelle Basin) and a large ultra deep-water depocentre (3000-3500 m) in the west (western Mentelle Basin). Interpretation of the new data revealed that initial rifting in the Mentelle Basin occurred in the Early Permian as part of the Perth Basin extensional system. This was followed by Late Permian to Early Jurassic thermal subsidence. Half-graben structures with Permo-Triassic fill have been mapped in the eastern Mentelle Basin. The main depositional phase in the western Mentelle Basin has been interpreted to correlate with Late Jurassic to Early Cretaceous extension in the Perth Basin and on the Southern Margin. New structural interpretation shows that in the northern part of the western Mentelle Basin, major structures are trending N-S similar to the Perth Basin, whereas in the south most structures are trending SW-NE, which is consistent with the orientation of the extensional basins on the Southern Margin. The proximity of the Southern Margin rift system not only affected the structure of the Mentelle Basin but also resulted in major fault reactivation, inversion and margin collapse in the Eocene corresponding to the onset of fast spreading in the Southern Ocean.