USGS analysis of the Australian UNCLOS submission

Open-File Report 2006-1073




In November 2004, the Government of Australia made a submission to the Commission on the Limits of the Continental Shelf (CLCS) for 10 extended continental shelf (ECS) regions, utilizing Article-76 of the United Nations Convention on the Law of the Sea (UNCLOS). With information provided in the Australian Executive Summary, the USGS examined the 10 regions of the submission from geological, morphological, and resource perspectives. By their own request, the Australians asked that CLCS take no action on the Australian-Antarctic Territory. The major limitation in this analysis is that no bathymetric soundings or detailed hydrographic profiles were provided in the Australian Executive Summary that might show why the Foot of the Slope (FOS) was chosen or where the 2,500-m contour is located. This represents a major limitation because more than half of the 4,205 boundary points utilize the bathymetric formula line and more than one-third of them utilize the bathymetric constraint line. CLCS decisions on the components of this submission may set a precedent for how ECSs are treated in future submissions. Some of the key decisions will cover (a) how a 'natural prolongation' of a continental margin is determined, particularly if a bathymetric saddle that appears to determine the prolongation is in deep water and is well outside of the 200-nm limit (Exmouth Plateau), (b) defining to what extent that plateaus, rises, caps, banks and spurs that are formed of oceanic crust and from oceanic processes can be considered to be 'natural prolongations' (Kerguelen Plateau), (c) to what degree UNCLOS recognizes reefs and uninhabited micro-islands (specifically, rocks and/or sand shoals) as islands that can have an EEZ (Middleton and Elizabeth Reefs north of Lord Howe Island), and (d) how the Foot of the Slope (FOS) is chosen (Great Australian Bight). The submission contains situations that are relevant to potential future U.S. submissions and are potentially analogous to certain features of the US margins. The Australian margin has significant geological and morphological variety, similar to the US margin and gives a good idea of the complexity of issues related to the U.S. margin. Decisions about basins and ridges in the Lord Howe Rise and Three Kings Ridge regions will likely bear on the status of ridges in the Arctic, such as Lomonosov Ridge. The Naturaliste Plateau and the South Tasman Rise appear to have parallels with the Chukchi Plateau in the Arctic and the Blake Plateau off the southeastern U.S. The ECS on Macquarie Island/Ridge may determine how boundaries along ridges such as the Mariannas are treated.

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USGS analysis of the Australian UNCLOS submission
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Open-File Report
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23 p.
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