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GNS scientist joins multi-national study of Pacific seabed - 14/08/1998

A marine geologist from the Institute of Geological & Nuclear Sciences Limited is to join scientists from 11 countries for a two-month deep-sea drilling project off New Zealand's east coast.

Gary Wilson, who specialises in studying magnetic fields in ancient rocks and sediment, said the project was a multi-national initiative to gain a better understanding of oceans, tectonic evolution, and global climate patterns.

Dr Wilson will join 20 scientists and a similar number of support staff in the state-of-the-art research ship Joides Resolution which is scheduled to take deep cores from seven locations in the Pacific and Southern Oceans.

A New Zealand Foundation for Research Science and Technology post-doctoral fellow, Dr Wilson said it was hoped the seabed cores would date back beyond 30 million years.

The project is part of the Ocean Drilling Programme (ODP), set up in 1985 by 22 member countries. In the past 13 years ODP projects have drilled at 1300 locations around the world.

The estimated cost of $NZ11.8 million for this project is being funded by mainly by the United States' National Science Foundation.

This will be the first time an ODP ship has drilled into the seabed to the east and southeast of New Zealand.

The shallowest drilling location is off the coast of Oamaru at about 300m. The deepest - about 4000m - is on the edge of the Hikurangi Trench, midway between the North Island and the Chatham Islands.

The cores will be brought to the surface in 10m lengths and sliced in two lengthwise for different groups of scientists to study on board.

Dr Wilson said the seabed to the east and southeast of New Zealand had been chosen because of it lay across the path of cold, dense Antarctic currents that flowed north along the bottom of the ocean and surfaced near the equator. It is thought some of the Antarctic water reaches the Arctic Circle.

As the currents carried millions of cubic metres of cold water every second, they were an important component of temperature transfer around the globe, and in the mixing of global ocean currents.

The currents travelled around the margins of the New Zealand continent depositing sediment and causing erosion. Dr Wilson said it was the sediment deposits and the fossils they contained that were the targets of the drilling programme.

Analytical capabilities of the on-board laboratory included paleontology, sedimentology, paleomagnetism, and geochemistry.

Shore-based studies of the cores would continue for up to a year after the ship docks in Wellington in early October.

Analysis of the sediment would hopefully provide new insights into the interaction of the oceans, the tectonic plates and climate in the Southern Hemisphere over the past 20 to 50 million years.

Results would also help scientists who build computer models that predict future climate change. Studies of cores taken from other oceans had helped scientists reconstruct ancient continents and climatic conditions over many millions of years.