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.

Map showing Australia's Maritime Jurisdiction in the Coral and Tasman Seas. 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, treaties and various maritime zones. Background bathymetric image is derived from a combination of the 2009 9 arc second bathymetric and topographic grid by GA and 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.

Map showing Australia's Maritime Jurisdiction off Northern Australia. This includes areas contiguous to the north of the continent and as far west as Christmas Island, but excludes areas around Cocos (Keeling) Islands and areas west of Christmas Island. 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, 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. 2800mm x 1050mm (for 42" plotter) sized .pdf downloadable from the web.

This map was created by GA for the purposes of seeking clarifications with AIMS and DFAT for survey work in the Timor Sea. A base map product was modified for the purpose.

Physical and biological characteristics of benthic communities are analysed from underwater video footage collected across the George V Shelf during the 2007/2008 CEAMARC voyage. Benthic habitats are strongly structured by physical processes operating over a range of temporal and spatial scales. Iceberg scouring recurs over timescales of years to centuries along shallower parts of the 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 physical processes of iceberg scouring, current regimes and depositional environments, in addition to water depth, are shown to be important factors in the structure of benthic communities across the George V Shelf. The modern shelf communities mapped in this study largely represent colonisation over the past 8-12ka, following retreat of the icesheet and glaciers at the end of the last glaciation (Harris et al., 2001; Ingólfsson et al., 1998). Recolonisation on this shelf may have occurred from two sources: deep-sea environments, and possible shelf refugia on the Mertz and Adélie Banks. However, any open shelf area would have been subject to intense iceberg scouring (Beaman and Harris, 2003). Understanding the timescales over which shelf communities have evolved and the physical factors which shape them, will allow better prediction of the distribution of Antarctic shelf communities and their vulnerability to change. This knowledge can aid better management regimes for the Antarctic margin.

In September and October of 2011 Geoscience Australia surveyed part of the offshore northern Perth Basin in order to map potential sites of natural hydrocarbon seepage. The primary objectives of the survey were to map the spatial distribution of seepage sites and characterise the nature of the seepage at these sites (gas vs oil, macroseepage vs microseepage; palaeo vs modern day seepage) on the basis of: acoustic signatures in the water column, shallow subsurface and on the seabed; geochemical signatures in rock and sediment samples and the water column; and biological signatures on the seabed. Areas of potential natural hydrocarbon seepage that were surveyed included proven (drilled) oil and gas accumulations, a breached structure, undrilled hydrocarbon prospects, and areas with potential signatures of fluid seepage identified in seismic, satellite remote sensing and multibeam bathymetry data. Within each of these areas the survey acquired: water column measurements with the CTD; acoustic data with single- and multi-beam echosounders, sidescan sonar and sub-bottom profiler (sidescan not acquired in Area F as it was too deep in places); and sediment and biological samples with the Smith-McIntyre Grab. In addition, data were collected with a remotely operated vehicle (ROV), integrated hydrocarbon sensor array, and CO2 sensor in selected areas. Sampling with the gravity corer had limited success in many of the more shallow areas (A-E) due to the coarse sandy nature of the seabed sediments. This dataset comprises mineraology of the upper 2cm of seabed sediment. The mineral assemblage includes quartz, aragonite, calcite and high-Mg calcite expressed as mol %.

In September and October of 2011 Geoscience Australia surveyed part of the offshore northern Perth Basin in order to map potential sites of natural hydrocarbon seepage. The primary objectives of the survey were to map the spatial distribution of seepage sites and characterise the nature of the seepage at these sites (gas vs oil, macroseepage vs microseepage; palaeo vs modern day seepage) on the basis of: acoustic signatures in the water column, shallow subsurface and on the seabed; geochemical signatures in rock and sediment samples and the water column; and biological signatures on the seabed. Areas of potential natural hydrocarbon seepage that were surveyed included proven (drilled) oil and gas accumulations, a breached structure, undrilled hydrocarbon prospects, and areas with potential signatures of fluid seepage identified in seismic, satellite remote sensing and multibeam bathymetry data. Within each of these areas the survey acquired: water column measurements with the CTD; acoustic data with single- and multi-beam echosounders, sidescan sonar and sub-bottom profiler (sidescan not acquired in Area F as it was too deep in places); and sediment and biological samples with the Smith-McIntyre Grab. In addition, data were collected with a remotely operated vehicle (ROV), integrated hydrocarbon sensor array, and CO2 sensor in selected areas. Sampling with the gravity corer had limited success in many of the more shallow areas (A-E) due to the coarse sandy nature of the seabed sediments. This dataset comprises chlorophyll a,b, and c and phaeophyton a measurements from the surface 0.5 cm of seabed sediments

Geoscience Australia undertook a marine survey of the Leveque Shelf (survey number SOL5754/GA0340), a sub-basin of the Browse Basin, in May 2013. This survey provides seabed and shallow geological information to support an assessment of the CO2 storage potential of the Browse sedimentary basin. The basin, located on the Northwest Shelf, Western Australia, was previously identified by the Carbon Storage Taskforce (2009) as potentially suitable for CO2 storage. 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 principal aim of the Leveque Shelf marine survey 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 Leveque Shelf area that may extend to the seabed. The survey also mapped seabed habitats and biota to provide information on communities and biophysical features that may be associated with seepage. This research, combined with deeper geological studies undertaken concurrently, addresses key questions on the potential for containment of CO2 in the basin's proposed CO2 storage unit, i.e. the basal sedimentary section (Late Jurassic and Early Cretaceous), and the regional integrity of the Jamieson Formation (the seal unit overlying the main reservoir). This dataset comprises total chlorin concentrations and chlorin indices from the upper 2cm of seabed sediments.

Geoscience Australia undertook a marine survey of the Leveque Shelf (survey number SOL5754/GA0340), a sub-basin of the Browse Basin, in May 2013. This survey provides seabed and shallow geological information to support an assessment of the CO2 storage potential of the Browse sedimentary basin. The basin, located on the Northwest Shelf, Western Australia, was previously identified by the Carbon Storage Taskforce (2009) as potentially suitable for CO2 storage. 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 principal aim of the Leveque Shelf marine survey 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 Leveque Shelf area that may extend to the seabed. The survey also mapped seabed habitats and biota to provide information on communities and biophysical features that may be associated with seepage. This research, combined with deeper geological studies undertaken concurrently, addresses key questions on the potential for containment of CO2 in the basin's proposed CO2 storage unit, i.e. the basal sedimentary section (Late Jurassic and Early Cretaceous), and the regional integrity of the Jamieson Formation (the seal unit overlying the main reservoir). This dataset comprises total chlorin concentrations and chlorin indices from the upper 2cm of seabed sediments.

Map showing Australia's Maritime Jurisdiction around the around Cocos (Keeling) Islands and Christmas Island. 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, treaties and various maritime zones. Background bathymetric image is derived from a combination of the 2009 9 arc second bathymetric and topographic grid by GA and a grid by Smith and Sandwell, 1997. A0 sized .pdf downloadable from the web.