HR: 12:05h
AN: T12C-08    [Abstracts]
TI: The Bay of Bengal and the Statement of Understanding Concerning the Establishment of the Outer Edge of the Continental Margin: Regional Implications for Delimiting the Juridical Continental Shelf
AU: * Mridha, M
EM: md882074@dal.ca
AF: Marine Affairs Program, Dalhousie University 1376 LeMarchant Street, Halifax, NS B3H 3P9 Canada
AU: Varma, H
EM: varmah@mar.dfo-mpo.gc.ca
AF: Canadian Hydrographic Service, Bedford Institute of Oceanography PO Box 1006, Dartmouth, NS B2Y 4A2 Canada
AU: Macnab, R
EM: ron.macnab@ns.sympatico.ca
AF: Geological Survey of Canada (Retired), 11 Lyngby Avenue, Dartmouth, NS B3A 3T6 Canada
AB: The Bay of Bengal is the site of massive depositions of sediment from the Ganga-Brahmaputra river systems, which discharge an estimated 2300 million tons of material into the Indian Ocean every year. The accumulated material comprises an enormous fan that extends some 4000 km from the Mouths of the Ganges, a delta system which encompasses the entire coast of Bangladesh and a segment of the coast of India. The major tectonic elements of the Bay of Bengal and surrounding areas are: the passive eastern continental margin of India; the 85E Ridge; the Ninetyeast Ridge; the intervening basin buried beneath deep sediment; and the Sunda Arc system with the associated back-arc Andaman Basin. Except for the Nikitin Seamounts which rise above the seabed just south of the Equator, the 85E Ridge is totally covered by thick sediment. The Ninetyeast Ridge, on the other hand, protrudes above the seabed as far north as 10N, where it plunges beneath the thickening sediment and separates the deposits into the Bengal Fan and the smaller Nicobar Fan. The 85E and Ninetyeast Ridges present the most significant relief in the crystalline basement underlying the Bay of Bengal, and should therefore figure substantially in any analysis of sediment thickness pursuant to the delimitation of the outer continental shelf. In this region, the sediment thickness provision of Article 76 has been modified by a Statement of Understanding in Annex II of the Final Act of the Third UN Conference on the Law of the Sea. To avoid a perceived inequity that might arise from the application of the standard one percent sediment thickness formula of Article 76, the Statement introduced a new formula: a qualified State in this region, even if it has a narrow physiographic continental shelf, may establish the outer edge of its continental margin by a line where the thickness of sedimentary rock is not less than one km. This presentation will describe the development of a joint formula line for the States that border the Bay of Bengal, taking into account the provisions of the Statement of Understanding. The input data for this analysis consisted of a public grid of sediment thickness, created from the archives of the US National Geophysical Data Center. The outcome of this investigation indicates that the entire Bay of Bengal can be enclosed by the modified formula line. Following application of the joint 350 nautical mile constraint line for all coastal States in the region, it would appear moreover that the entire floor of the Bay of Bengal comprises a juridical continental shelf.
DE: 3022 Marine sediments: processes and transport
DE: 3045 Seafloor morphology, geology, and geophysics
DE: 8106 Continental margins: transform
DE: 8150 Plate boundary: general (3040)
SC: Tectonophysics [T]
MN: Fall Meeting 2005