Publication Name: Eastern Australian Basins Symposium 2001
Authors: P.A. Symonds, R. Parums, G. Hill, B. Hirst, G. Bernardel and H. Stagg
Date Published: November 2001
Number of Pages: 36
Reference Type: Magazine Article
Abstract:
The outer limit of the seabed and subsoil resource regime off the eastern half of Australia - the Continental Shelf - is based on boundaries agreed with neighbouring countries in the north and northeast, and a variety of boundaries with the international community, and yet to be agreed with New Zealand, in the east and southeast. The rules for defining the outer limits with respect to the international community are contained in the 1982 United Nations Convention on the Law of the Sea (UNCLOS). Where the continental margin extends beyond the 200nautical mile (M) Australian Exclusive Economic Zone (AEEZ) definition of the outer limit requires information on the morphology, sediment thickness distribution and bathymetry of the margin and adjacent sea floor. Since 1994, AGSO - Geoscience Australia has been conducting surveys across the margins of Australia and its island territories for this purpose, and has acquired about 40,000 km of deep-seismic, swath bathymetric and other data off eastern Australia.
The Continental Shelf off eastern Australia extends beyond the AEEZ in five areas: the Lord Howe Rise/Norfolk Ridge, the northern Three Kings Ridge, the South Tasman Rise, the southern Macquarie Ridge and the central Great Australian Bight. These cover about 1.1 million km2, and, together with the 5.1 million km2 AEEZ, the Territorial Sea and other state jurisdictions will result in a full marine resource jurisdiction of about 6.8 million km2 - 88% of the size of the Australian landmass.
Only the inner shallow-water part of the jurisdiction, mainly in the Bass Strait region and off Darwin, has been explored for petroleum; however, the recent release of deep-water acreage in the Great Australian Bight has stimulated interest in this area. Significant opportunities for frontier petroleum exploration exist beyond the geomorphic shelf, and possibly in less conventional play-types on plateaus/rises, and adjacent basins and troughs, that extend beyond the AEEZ, such as the Lord Howe Rise/New Caledonia Basin, and the South Tasman Rise. In places there is evidence for the presence of unconventional hydrocarbon resources in the form of
gas hydrates. Some features with petroleum potential, particularly off northeast Australia, lie within and adjacent to marine parks and protected zones and are likely to remain controversial areas for exploration.
The eastern part of Australia's marine jurisdiction is a vast, diverse and complex region of seafloor over which the nation will have the right and responsibility to manage the marine environment to ensure long-term ecological sustainability for a wide range of ocean uses.