Hydrographic Report

Number crunching time for Continental Shelf Project

by Russell Turner, Contracts Manager, Land Information New Zealand. rturner@linz.govt.nz

A 'bird' being attached to the streamer during low fold seismic surveying.

The action is now returning to dry land for the Government project to define the boundaries of New Zealand's continental shelf. LINZ is leading the technical aspects of the project and will provide a series of reports and supporting geographical information to the Ministry of Foreign Affairs and Trade so the Ministry can present New Zealand's continental shelf territorial claim to the United Nations by 2006.

Multibeam data in the Bollons Seamount region.

For those involved at the 'wet' end of the project, the wrap-up of the survey work could be welcome news. According to LINZ Project Leader Russell Turner the last low-fold seismic survey carried out in May and June 2002 on the RV Tangaroa was done in some of the roughest weather ever experienced by the team.

The only sea work remaining is one more rock dredging survey to be carried out in November. Russell says the RV Sonne will dredge to a depth of up to 5000 metres in the Colville Ridge area to the northeast of New Zealand near Raoul Island. "What we're looking for is evidence of continental rock, as opposed to typical oceanic rock normally found beyond the continental shelf. If we find rocks of continental nature in the dredge samples, that will help build the evidence we are gathering on the extent of our continental shelf."

The dredging, which complements the seismic and other data gathering, has also been carried out on the Campbell Plateau, Resolution Ridge, Chatham Rise and Bollons Seamount areas. Russell says that the analysis of samples brought up to the surface sometimes yields equivocal results, but in some areas they have helped confirm that New Zealand's continental shelf extends well beyond the borders of its 200 nautical mile Exclusive Economic Zone.

The Institute of Geological and Nuclear Sciences is carrying out the geological interpretation of the dredge samples, with some of the sample analyses being carried out in overseas laboratories which can take up to eight months.

Russell says the focus is now swinging towards the data analysis and report writing. "The surveys have revealed six areas within the continental margins, for which separate reports will be prepared.

Aboard the RV Melville.

"Only one continental shelf submission has been made to the UN so far - from the Russian Federation - so we're breaking new ground in terms of how to prepare our case," Russell says. "We will be presenting both hard copy and digital copies of the reports, including sophisticated graphics. The process will be thoroughly documented - we will be showing the methodologies used and QA information to underline the integrity of what we're saying."

The New Zealand team is working closely with its Australian counterparts to help ensure a coordinated approach when the respective countries make their submissions. Australia is likely to put its submission to the UN in 2004 with New Zealand following in 2006. The UN has recently extended the deadline for submission of New Zealand's case to 2009. Russell says that while this extension relieves some pressure on the programme, it is still geared towards a 2006 delivery date.

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