HR: 1340h
AN: T13D-0507    [Abstracts]
TI: Actively Spreading Plate Boundaries and UNCLOS: the Difficulties of Applying Article 76
AU: Evans, A
EM: alje@noc.soton.ac.uk
AF: National Oceanography Centre, European Way, Southampton, Han SO51 0PE United Kingdom
AU: Carleton, C
EM: Chris.Carleton@ukho.gov.uk
AF: United Kingdom Hydrographic Office, Admiralty Way, Taunton, DT14 3tk United Kingdom
AU: * Parson, L
EM: L..Parson@soc.soton.ac.uk
AF: National Oceanography Centre, European Way, Southampton, Han SO51 0PE United Kingdom
AB: The process by which the delineation of a legal continental shelf according to the United Nations Convention on the Law of the Sea (UNCLOS) is made for an oceanic island territory beyond 200 nautical miles causes significant confusion for both researchers on the issue and coastal states' representatives trying to apply the provisions within Article 76. The interpretation of the statutory provisions set out in UNCLOS and the Technical and Scientific guidelines laid out by the Commission on the Limits of the Continental Shelf (CLCS) remain, for the most part, difficult to implement. This global summary of oceanic islands and their geological context with respect to the Law of the Sea Convention, and in particular regarding mid-ocean ridge systems, brings to light some of the problems responsible for this confusion and attempts to resolve the uncertainty associated with ridge issues with a practical and equitable delimitation proposal. Paragraph 6 of Article 76 requires a constraint/limit of 350M from the territorial sea baselines on submarine ridges, (one assumes, to ensure that no coastal state claims the entire mid-ocean ridge!). However the criteria set in paragraph 4a(i) or 4a(ii) of Article 76, which provide the means to extend a legal continental shelf beyond 200M based on the identification of a morphological foot of slope, cannot be applied to oceanic island territories because of difficulties in determining its consistent and practical location. Accordingly the advantages and disadvantages of several geophysical data types have been evaluated for their use under paragraph 4 (b) of Article 76 (definition of the foot of the slope on "evidence to the contrary"). Our proposed method of using the central, zero-age locus of the mid oceanic ridge, whether this may be the ridge line, bathymetric maxima or spreading centre, as a representation of the foot of slope (based on evidence to the contrary), results in a simple, fair and consistent way of developing an area of extended LCS between the 200M and 350M limits. Inevitably there will be difficulties in implementing this strategy - not least of which will be identifying the axial line of a spreading system along complex sections of ridge. A wide range of supporting geophysical datasets may need to synthesised, including perhaps magnetics, gravity, etc. While it is widely agreed that the understanding of this part of Article 76 is one of the most challenging and least addressed to date, it is clear that a large number of island states are likely to benefit form claims of this kind - among them we note (potentially) Ecuador, Iceland, Portugal, the UK, South Africa, among others.
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
DE: 3099 General or miscellaneous
DE: 8104 Continental margins: convergent
DE: 8105 Continental margins: divergent (1212, 8124)
DE: 8106 Continental margins: transform
SC: Tectonophysics [T]
MN: Fall Meeting 2005