Large barchan shaped sand deposits have been observed in the north west of Torres Strait. These deposits share characteristics of both subaerial barchan dunes and subaqueous sand banks. Satellite imagery shows that the deposits migrate in the direction indicated by their horns (10-15 m west per year), and that sediment is shed from their horns, features that are characteristic of subaerial barchan dunes. However the orientation of sandwaves superimposed upon the sand banks indicate the presence of mutually evasive channels and circulation of sediment around the sand bank, a characteristic of subaqueous sand banks. The presence of mutually evasive channels is the criteria used to categorise the deposits as sand banks. Barchan forms are known to exist in regions with limited sediment supply and unidirectional current or wind regimes. In the Torres Strait both these criteria are met. Previous work has demonstrated the presence of a net westward current through the Torres Strait that is driven by the southeast trade winds. The relatively high displacement of the wind driven currents during the trade wind season relative to the monsoon appears to provide the necessary "unidirectional" regime to form barchans. The low, and typically eastwards, displacement of the residual monsoon season current appears to have a negligible affect on the barchan form.

Geoscience Australia undertook seabed mapping surveys in the eastern Bonaparte Gulf in 2009/2010 to deliver integrated information relevant to marine biodiversity conservation and offshore infrastructure development. The survey objectives were to characterise the physical, chemical and biological properties of the seabed, document potential geohazards and identify unique or sensitive benthic habitats. Different clustering methods were applied to a 124 sample dataset comprising 74 physical and chemical variables which convey important baseline information about sediment sources, carbon reactivity/redox and sedimentary environments. Results of the UPGMA clustering method were interpreted due to the high cophenetic correlation (0.82), and these clusters discriminated infauna better than clusters based on geomorphology. Major geochemical dimensions evident amongst clusters included grain-size and a cross-shelf transition from Mn and As enrichment (inner shelf) to P enrichment (outer-shelf). Higher P was due to enhanced authigenic-P accumulation. Sponge/gorgonian occurrences were constrained by low Nd/Sr (pointing to a diminishing terrestrial source) and relatively high -15N, and subsurface seepage was shown to enhance the 'terrestrial' (e.g. rare-earth element and Si) signature in outer-shelf sediments. Sponge-dominated shallow bank/terrace clusters with abundant reactive organic matter differentiated on the basis of Si-Al relations (and redox). These habitats shed materials to peripheral Gorgonian-dominated scree environments which had surface-area normalised TOC concentrations that were elevated over usual continental shelf ranges. Trichodesmium were identified as an important source of carbon to inner-shelf plains. Pair-wise ANOSIM results for infauna are brought together in a summary model which highlights the influence of the clusters on benthic biodiversity.

Physical and biological characteristics of benthic communities on the George V Shelf have been analysed from underwater camera footage collecting during Aurora Australis voyages in 2007/08 and 2010/11. The 2007/08 data revealed a high degree of variability in the benthic communities across the shelf, with the benthic habitats strongly structured by physical processes. Iceberg scouring recurs over timescales of years to centuries along shallower parts of this shelf, creating communities in various stages of maturity and recolonisation. Upwelling of modified circumpolar deep water (MCDW) onto the outer shelf and cross-shelf flow of high salinity shelf water (HSSW) create spatial contrasts in nutrient and sediment supply, which are largely reflected in the distribution of deposit and filter feeding communities. Long term cycles in the advance and retreat of icesheets (over millennial scales) and subsequent focussing of sediments in troughs such as the Mertz Drift create patches of consolidated and soft sediments, which also provide distinct habitats for colonisation by different biota. These interacting physical processes of iceberg scouring, current regimes and depositional environments, in addition to water depth, are important factors in the structure of benthic communities across the George V Shelf. In February 2010, iceberg B09B collided with the Mertz Glacier Tongue, removing about 80% or 78km from the protruding tongue. This event provided a rare opportunity to access a region previously covered by the glacier tongue, as well as regions to the east where dense fast ice has built up over decades, restricting access. The 2010/11 voyage imaged 3 stations which were previously beneath the floating tongue, as well as 9 stations covered by multi-year and annual fast ice since the mid 1970s.

Prydz Bay and the Mac.Robertson Land Shelf exhibit many of the variations seen on Antarctic continental shelves. The Mac.Robertson Shelf is relatively narrow with rugged inner shelf topography and shalow outer banks swept by the west-flowing Antarctic Coastal Current. U-shaped valleys cut the shelf. it has thin sedimentary cover deposited and eroded by cycles of glacial advance and retreat through the Neogene and Quaternary. Modern sedimention is diatom-rich Siliceosu Muddy OOze in shelf deeps while on the banks, phytodetritus, calcareous bioclasts and terrigenous material are mixed by iceberg ploughing. Prydz Bay is a large embayment fed by the Amery Ice Shelf. it has a broad inner shelf deep and outer bank with depths ranging from 2400 m beneath the ice shelf to 100 m on the outer bank. A clockwise gyre flows through the bay. Fine mud and siliceous ooze drapes the sea floor however banks are scoured by icebergs to depths of 500 m.

Modified to go up to 5°S for use of client only in July 2013 from GeoCat 71985. Not for sale or general release. For use of client department only. Map showing all of Australia's Maritime Jurisdiction north of approx 25°S . This includes areas around Cocos (Keeling) Islands and areas west of Christmas Island as well as those contiguous to the continent in the north. Including data concerned with jurisdictions of other nations and as such not for general release. Depicting Australia's extended continental shelf approved by the Commission on the Limits of the Continental Shelf in April 2008, treaties and various maritime zones. Background bathymetry image is derived from a combination of the 2009 9 arc second bathymetry and topographic grid by Geoscience Australia and a grid by W.H.F. Smith and D.T. Sandwell, 1997. Background land imagery derived from Blue Marble, NASA's Earth Observatory. For 42" plotter, sized .pdf

This resource contains multibeam sonar backscatter data for the continental shelf area of Flinders Commonwealth Marine Reserve, northeast Tasmania. Multibeam data were collected by Geoscience Australia and University of Tasmania in May 2011 (survey GA0331) and June-July 2012 (survey GA0337) on RV Challenger. The survey used a Kongsberg EM3002 300 kHz multibeam sonar system mounted in single head configuration to broadly classify the seabed into hard (bedrock reef), soft (sedimentary) and mixed substrate types at select locations across the shelf. The 2011 survey involved reconnaissance mapping along a series of cross-shelf transects, covering a total of 767 line km. For the 2012 survey, multibeam data (bathymetry and backscatter) were collected at 40 pre-determined stations, each covering an area approximately 200 x 200 m. The location of stations was selected using a Generalised Random Tessellation Stratified (GRTS) sampling design that ensured an even spatial distribution of sites. Multibeam data was also collected along transits between GRTS stations (410 line km) and across a 30 km2 area of the outer shelf, incorporating areas of low profile reef, sandy shelf and three shelf-incising canyon heads. Backscatter data are gridded to 2 m spatial resolution. The 2012 survey also included seabed observations at the 40 GRTS stations using a drop camera and collection of sediment samples at 31 stations using a Shipek grab. The Flinders CMR survey was a pilot study undertaken in 2012 as part of the National Marine Biodiversity Hub's National Monitoring Evaluation and Reporting Theme. The aim of this theme is to develop a blueprint for the sustained monitoring of the South-east Commonwealth Marine Reserve Network, specifically; 1) to contribute to an inventory of demersal and epibenthic conservation values in the reserve and 2) to test methodologies and deployment strategies in order to inform future survey design efforts. Several gear types were deployed; including multibeam sonar, shallow-water (less than 150m) Baited Remote Underwater Video Systems (BRUVS), deep- water BRUVS (to 600 m), towed video and digital stereo stills. Embargo statement: Resource embargoed pending completion of NERP research. Release date 31 December 2014. Attribution statement: Data was sourced from the NERP Marine Biodiversity Hub. The Marine Biodiversity Hub is supported through funding from the Australian Government's National Environmental Research Program (NERP), administered by the Department of Sustainability, Environment, Water, Population and Communities (DSEWPAC). Dataset name: National Environmental Research Program (NERP) Marine Biodiversity Hub, 2012, Flinders Commonwealth Marine Reserve Shelf Backscatter

Map showing Australia's Maritime Jurisdiction off the western portion of the Australian Antarctic Territory. One of the 27 constituent maps of the "Australia's Maritime Jurisdiction Map Series" (GeoCat 71789). Depicting Australia's extended continental shelf approved by the Commission on the Limits of the Continental Shelf in April 2008 and various maritime zones. Background bathymetric image is derived from a grid by Smith and Sandwell, 1997. Background land imagery derived from Blue Marble, NASA's Earth Observatory. A0 sized .pdf downloadable from the web.

As part of the Australian Government's National CO2 Infrastructure Plan (NCIP), Geoscience Australia has undertaken integrated assessments of selected offshore sedimentary basins for their CO2 storage potential. In March and April 2012, Geoscience Australia completed a seabed survey (GA0334) over two targeted areas (Area 1 and Area 2) of the Vlaming Sub-basin (Figure 1 1), as part of a larger study investigating the suitability of the Vlaming Sub-basin for geological storage of CO2. This document summarises the results and interpretation of seabed and shallow geological (to 30 m below the seabed) data acquired during survey GA0334 in the Vlaming Sub-basin. These data and their interpretations are being used to support the investigation of the Vlaming Sub-basin for CO2 storage potential.

Flythrough movie showing the bathymetry of the shelf surrounding Lord Howe Island (NSW), with examples of seabed habitats and biota. The bathymetric image is derived from merged grids (8 m and 40 m resolution) that incorporates multibeam sonar collected in 2008 using a 30 kHz Simrad EM300 system on RV Southern Surveyor, legacy sonar data from various sources and satellite-derived bathymetry (grid development detailed in GA Record 2010/36). Key features on the shelf bathymetry include a drowned reef that encircles the island and intervening areas of sediment-covered basins. Lord Howe Island shelf is a study site for the Marine Biodiversity Research Hub, funded through the Commonwealth Environment Research Facilities (CERF) programme. Further information is provided in GA Record 2010/26.

Geoscience Australia undertook a marine survey of the Vlaming Sub-basin in March and April 2012 to provide seabed and shallow geological information to support an assessment of the CO2 storage potential of this sedimentary basin. The survey was undertaken under the Australian Government's National CO2 Infrastructure Plan (NCIP) to help identify sites suitable for the long term storage of CO2 within reasonable distances of major sources of CO2 emissions. The Vlaming Sub-basin is located offshore from Perth, Western Australia, and was previously identified by the Carbon Storage Taskforce (2009) as potentially highly suitable for CO2 storage. The principal aim of the Vlaming Sub-basin marine survey (GA survey number GA334) was to look for evidence of any past or current gas or fluid seepage at the seabed, and to determine whether these features are related to structures (e.g. faults) in the Vlaming Sub-basin that may extend up to the seabed. The survey also mapped seabed habitats and biota in the areas of interest to provide information on communities and biophysical features that may be associated with seepage. This research addresses key questions on the potential for containment of CO2 in the Early Cretaceous Gage Sandstone (the basin's proposed CO2 storage unit) and the regional integrity of the South Perth Shale (the seal unit that overlies the Gage Sandstone). This dataset comprises grain size data and carbonate concentrations of the upper ~2cm of seabed sediment.