The Carnarvon shelf at Point Cloates, Western Australia, is characterised by a series of prominent ridges and hundreds of mounds that provide hardground habitat for coral and sponge gardens. The largest ridge is 20 m high, extends 15 km alongshore in 60 m water depth and is interpreted as a drowned fringing reef. To landward, smaller ridges up to 1.5 km long and 16 m high are aligned to the north-northeast and are interpreted as relict aeolian dunes. Mounds are less than 5 m high and may also have a sub-aerial origin. In contrast, the surrounding seafloor is sandy with relatively low densities of epibenthic organisms. The dune ridges are estimated to be Late Pleistocene in age and their preservation is attributed to cementation of calcareous sands to form aeolianite, prior to the postglacial marine transgression. On the outer shelf, sponges grow on isolated low profile ridges at ~85 m and 105 m depth and are also interpreted as partially preserved relict shorelines.

AMB is a dataset depicting the limits of Australia's maritime jurisdiction as set out under UNCLOS and relevant domestic legislation. To this extent, AMB provides a digital representation of the outer limit of the 12 nautical mile territorial sea, the 24 nautical mile contiguous zone, the 200 nautical mile Exclusive Economic Zone and Australia's Continental Shelf, as well as, the 3 nautical mile coastal waters. Where Australia has agreements with neighbouring countries these treaty lines are also included in the data. The dataset has been compiled by Geoscience Australia in consultation with other relevant Commonwealth Government agencies including the Attorney-General's Department, the Department of Foreign Affairs and Trade, as well as the Australian Hydrographic Office.

Benthic sediment sampling of Inner Darwin Harbour (GA0358) and shallow water areas in and around Bynoe Harbour (GA0359) was undertaken between May 29 and June 19, 2017. Partners involved in the surveys included Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and the Department of Environment and Natural Resources within the Northern Territory Government (NT DENR) (formerly the Department of Land and Resource Management (DLRM)). These surveys form part of a four year (2014-2018) science program aimed at improving knowledge about the marine environments in the regions around Darwin and Bynoe Harbour’s through the collection and collation of baseline data that will enable the creation of thematic habitat maps to underpin marine resource management decisions. This project is being led by the Northern Territory Government and is supported by the INPEX-led Ichthys LNG Project, in collaboration with - and co-investment from GA and AIMS. This dataset comprises total sediment metabolism, carbonate, organic isotope and organic and inorganic element measurements on seabed sediments.

A nationally-consistent wave resource assessment is presented for Australian shelf (<300 m) waters. Wave energy and power were derived from significant wave height and period, and wave direction hindcast using the AusWAM model for the period 1 March 1997 to 29 February 2008 inclusive. The spatial distribution of wave energy and power is available on a 0.1° grid covering 110'156° longitude and 7'46° latitude. Total instantaneous wave energy on the entire Australian shelf is on average 3.47 PJ. Wave power is greatest on the 3,000 km-long southern Australian shelf (Tasmania/Victoria, southern Western Australia and South Australia), where it widely attains a time-average value of 25-35 kW m-1 (90th percentile of 60-78 kW m-1), delivering 800-1100 GJ m-1 of energy in an average year. New South Wales and southern Queensland shelves, with moderate levels of wave power (time-average: 10-20 kW m-1; 90th percentile: 20-30 kW m-1), are also potential sites for electricity generation due to them having a similar reliability in resource delivery to the southern margin. Time-average wave power for most of the northern Australian shelf is <10 kW m-1. Seasonal variations in wave power are consistent with regional weather patterns, which are characterised by winter SE trade winds/summer monsoon in the north and winter temperate storms/summer sea breezes in the south. The nationally-consistent wave resource assessment for Australian shelf waters can be used to inform policy development and site-selection decisions by industry.

Abstract: The extent to which fluids may leak from sedimentary basins to the seabed is a critical issue for assessing the potential of a basin for carbon capture and storage. The Petrel Sub-basin, located beneath central and eastern Joseph Bonaparte Gulf in tropical northern Australia, is identified as potentially suitable for the geological storage of CO2 because of its geological characteristics and proximity to offshore gas and petroleum resources. In May 2012, a multidisciplinary marine survey was undertaken to collect data in two targeted areas of the Petrel Sub-basin to facilitate an assessment of CO2 storage potential. Multibeam bathymetry and backscatter mapping (650 km2 over 5,300 line km), combined with acoustic sub-bottom profiling (650 line km) and geomorphological and sediment characterisation of the seabed was undertaken above the CO2 supercritical seal boundary of the sub-basin. Features identified in the high resolution (2 m) bathymetry data include carbonate banks, ridges, pockmark fields and fields of low amplitude hummocks located directly adjacent to banks. Unit and composite pockmarks and clusters of pockmarks are present on plains and adjacent to, and on, carbonate ridges. It is postulated that there are three possible sources for fluids and fluidised gas involved in pockmark formation: deep fluids from the basin, post-Cretaceous intra-formational, layer-bound fluids, and shallow-sourced fluidised gas from the breakdown of organic matter following the Holocene marine transgression of Joseph Bonaparte Gulf.

Abstract to appear in conference proceedings as part of GA Record

The movie describes the marine reconnaisance and seismic surveys undertaken between November 2008 and February 2009 as part of the South-West Margin Project. This is part of the broader part of the Energy Security Program. Video and still images from the marine reconnaisance and seismic surveys. Seismic cross-sections. Bathymetric flythroughs

The legacy of multiple marine transgressions is preserved in a complex morphology of ridges, mounds and reefs on the Carnarvon continental shelf, Western Australia. High-resolution multibeam sonar mapping, underwater photography and sampling across a 280 km2 area seaward of the Ningaloo Coast World Heritage Area shows that these raised features provide hardground habitat for modern coral and sponge communities. Prominent among these features is a 20 m high and 15 km long shore-parallel ridge at 60 m water depth. This ridge preserves the largely unaltered form of a fringing reef and is interpreted as the predecessor to modern Ningaloo Reef. Landward of the drowned reef, the inner shelf is covered by hundreds of mounds (bommies) up to 5 m high and linear ridges up to 1.5 km long and 16 m high. The ridges are uniformly oriented to the north-northeast and several converge at their landward limit. On the basis of their shape and alignment, these ridges are interpreted as relict long-walled parabolic dunes. Their preservation is attributed to cementation of calcareous sands to form aeolianite, prior to the post-glacial marine transgression. Some dune ridges abut areas of reef that rise to sea level and are highly irregular in outline but maintain a broad shore-parallel trend. These are tentatively interpreted as Last Interglacial in age. The mid-shelf and outer shelf are mostly sediment covered with relatively low densities of epibenthic biota and have patches of low-profile ridges that may also be relict reef shorelines. An evolutionary model for the Carnarvon shelf is proposed that relates the formation of drowned fringing reefs and aeolian dunes to Late Quaternary eustatic sea level.

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.

Map showing Australias Maritime Jurisdiction post UN recommendation in April 2008 Map produced for Dfat for inclusion in IOR-SRC website. Developed from Geocat 68133 (2008)