Scientists drill deep to uncover sea's secrets

An international team of scientists is to spend two months drilling the seabed off the coast of Canterbury to track the history of global sea level changes over the past 30 million years.

Sediment samples from as deep as 1800m beneath the seafloor will be targeted at six sites by the Integrated Ocean Drilling Programme, using the research drilling vessel Joides Resolution.

New Zealand researchers, led by GNS Science, have joined the programme as part of an Australian and New Zealand consortium with the Government's Foundation for Research Science and Technology, and universities at Wellington, Dunedin, Christchurch, Hamilton and Auckland.

Their combined annual membership fee of US$280,000 ($496,000) contributes to the operational costs of more than US$6 million an expedition.

GNS Science said it was considering expanding the consortium to include Asian countries.

The Canterbury expedition will attempt to understand the relative importance of global sea levels compared with local earthquakes and upthrust along the Southern Alps, and erosion in the dumping of sediment along the continental shelf.

Analysis of the samples may provide more information on the early history of the Alpine Fault plate boundary.

And researchers will look for indications of the start of circulation by major ocean currents, including the Antarctic Circumpolar Current in its earliest form.

The ship will stop at Wellington before travelling on to Antarctica in January 2010, to drill off the coast of Wilkes Land, in waters up to 3705m deep.

Wilkes Land is under part of the East Antarctic Ice Shelf, 3000km south of Australia.

The drill cores are expected to cast light on the inception and development of Antarctica's ice shelves.

- NZPA