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Cold seeps and hydrothermal vents can be detected by a number of oceanographic and geophysical techniques as well as the recovery of characteristic organisms. While the definitive identification of a seep or vent and its accompanying fauna is seldom unequivocal without significant effort. We suggest an approach to identifying associated VMEs in the CCAMLR region that uses the results of scientific surveys to identify confirmed features while documenting a series of criteria that can be used by fishing vessels to reduce the accidental disturbance of seep communities.

The rifting history of the magma-poor conjugate margins of Australia (Great Australian Bight) and Antarctica (Terre Adélie) is still a controversial issue. In this paper, we present a model for lithosphere-scale rifting and deformation history from initial rifting to breakup, based on the interpretation of two regional conjugate seismic profiles of the margins, and the construction of a lithosphere-scale, balanced cross section, sequentially restored through time. The model scenario highlights the symmetric pattern of initial stretching resulting to pure shear at lithospheric-scale accompanied by the development of four conjugate detachments and crustal half-graben systems. This system progressively evolves to completely asymmetric shearing along a single south-dipping detachment at the scale of the lithosphere. The detachment accounts for the exhumation of the mantle part of the Australian lithosphere, and the isolation of a crustal klippe separated from the margin by a peridotite ridge. Antarctica plays the role of the upper plate with the formation of an external crustal high separated from the unstretched continental crust by a highly extended zone still active during the Australian exhumation phase. The total elongation amount of the Australian-Antarctic conjugate system reaches ~413km (61%). Elongation was partitioned through time: ~189km and ~224km during symmetric and asymmetric stages, respectively. During symmetric stage, both margins suffered relatively the same elongation accommodated by crustal stretching (~105km (45%) and ~84km (38%) for Australia and Antarctica, respectively). Again, both margins accommodated relatively the same elongation during the asymmetric stage: the Antarctic upper plate records an elongation amount of ~225km (40%) as crustal tectonic stretching, above the inferred low-angle south dipping detachment zone, whereas the Australian lower plate suffered ~206km (61%) of elongation through mantle exhumation.

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.

This record is a compilation of the abstracts of oral and poster papers presented at a symposium held at the Bureau of Mineral Resources, Canberra 13-16 February 1989. The symposium was entitled "Seismicity and Earthquake Studies in the Australian Plate and its Margins", and was co-sponsored by the Specialist Group on Solid Earth Geophysics of the Geological Society of Australia and the Bureau of Mineral Resources. The abstracts in this paper are in the same order as in the symposium program at the beginning of the paper.

Two- and three-dimensional (2D and 3D) seismic stratigraphic interpretation, palaeobathymetric analysis from benthic foraminifera, and 2D forward tectonic modelling are combined to understand the genetic significance of prominent seismic discontinuity surfaces typically mapped as ?sequence boundaries? and ?flooding surfaces?, and their intervening sequences. Integration of these data has allowed interpretation of the Tertiary, heterozoan (i.e., non-photozoan) carbonate-dominated succession detailing the evolution of five prograding clinoformal sequences (2-5 m.y. duration), and 19 sub-sequences (<0.5-1 m.y. duration), along the Rankin Trend. Variations in accommodation space as modelled across the Dampier Sub-basin using 2D kinematic and flexural modelling are the combined result of synrift and postrift thermal subsidence, inversion and eustatic variations. The major observations and implications of this study are: ? Onlap onto the clinoform front of primary mappable surfaces is submarine with minimum estimated palaeo-water depths > 100 m at the shelf edge. Exposure surfaces identified in the middle Miocene are seismically less prominent, with potential karstification identified 6-8 km inboard of shelf edges. ? Systems tracts could not be consistently identified in the progradation-dominated succession. Lowstand basin-floor fans/aprons and transgressive systems tracts are largely absent on the seismic scale, resulting in downlap directly onto sequence boundaries. ? Linear, 30-80 km along strike, two-dimensional mapped sequences, are the integration of local sedimentary lobes up to 10 km in diameter. ? Canyon development may be controlled by inclination on gully failure walls rather than variations in sea level. Gully initiation is coincident with the mid-Miocene climatic Optimum. However, once established, erosion paths are maintained and enlarged by downslope sediment flows, derived from headward failure, regardless of proposed sea-level variations. ? The magnitude of inversion-related uplift is small, reaching a maximum of ~50-70 m at anticlinal crests focussed along the Rankin, Madeleine and Rosemary trends. Although this is of a similar scale to postulated eustatic variations that increase or decrease accommodation space across the entire margin, unconformities and onlap discontinuity surfaces related to these inversion structures are areally restricted.

This paper gives an interpretation of the continental margin off Willkes Land and Terre Adelie, East Antarctica, concentrating on the transition from continental to oceanic crust. The interpretation is based on the deep-seismic and potential field data acquired under the Australian Antarctic and Southern Ocean Profiling Project in 2001 and 2002.

The rifted margins of eastern and southern Australia formed during multiple periods of extension associated with the fragmentation and dispersal of Gondwana in the Late Jurassic to Early Eocene (Veevers & Ettreim 1988; Veevers et al. 1991). The sedimentary basins of the Southern Rift System (Stagg et al. 1990) extend from Broken Ridge in the west, to the South Tasman Rise (STR) in the east. Collectively, these depocentres cover an area in excess of 1 million square kilometres (excluding the STR), with the thickest sediments (up to 15 km) occurring in the Ceduna Sub-basin of the Bight Basin. Early phases of the extension during the late Middle Jurassic to Early Cretaceous resulted in the formation of a series of west-northwesterly trending continental rift basins along the southern margin of Australia and a series of north-northwest trending transtensional basins along the western margin of Tasmania. The amount of upper crustal extension varied between basins of the rift system. This phase of upper crustal extension preceded eventual breakup between the Australian and Antarctic plates off the Bight Basin in the latest Santonian to earliest Campanian (Sayers et al. 2001). The nature of source rocks within the rift basins reflects the eastward propagation of the rift system through time, with largely terrestrial systems dominating in the early rift stages, followed by marine inundation from the Aptian onwards (west of the Otway Basin). In the Otway Basin, the first marine influence is recorded during the early Turonian, while in the Sorell and Bass basins marine conditions prevailed from ?Maastrichtian and middle Eocene time, respectively. Terrestrial progradational systems in the Late Cretaceous are important in the maturation of potential source rocks in the Bight and Otway basins, while Neogene carbonate-dominated systems are important in the Sorell, Bass and Gippsland basins. Outside of the Gippsland Basin where exploration has reached a mature status, the southern margin basins remain frontier to moderately exploration areas, with an overall drilling density (excluding the Gippsland Basin) of approximately 1 well per 6,000 square kilometres. Key Words: Australian Southern Margin, Southern Rift System, petroleum systems References SAYERS, J., SYMONDS, P.A., DIREEN, N.G. and BERNARDEL, G., 2001. Nature of the continent-ocean transition on the non-volcanic rifted margin of the central Great Australian Bight. In, Wilson, R.C.L., Whitmarsh, R.B., Taylor, B., and Froitzheim, N., (Eds), Non-Volcanic Rifting of Continental Margins; A Comparison of Evidence from Land and Sea. Geological Society, London, Special Publications, 187, 51?77. STAGG, H.M.J., COCKSHELL, C.D., WILLCOX, J.B., HILL, A., NEEDHAM, D.J.L., THOMAS, B., O?BRIEN, G.W. and HOUGH, P., 1990. Basins of the Great Australian Bight region, geology and petroleum potential. Bureau of Mineral Resources, Australia, Continental Margins Program Folio 5. VEEVERS, J.J. and ETTREIM, S.L., 1988. Reconstruction of Australia and Antarctica at breakup (95 ? 5 Ma) from magnetic and seismic data at the continental margin. Australian Journal of Earth Sciences, 35, 355?362. VEEVERS, J.J., POWELL, C.MCA. and ROOTS, S.R., 1991. Review of seafloor spreading around Australia, I. Synthesis of the patterns of spreading. Australian Journal of Earth Sciences, 38, 373?389. WILLCOX, J.B. and STAGG, H.M.J., 1990. Australia?s southern margin, a product of oblique extension. Tectonophysics, 173, 269?281.

This document will be posted on the GA and CSIRO-Marine websites. Dr. Neville Exon was Chief Scientist and Cruise Leader for this survey.