Seabed drilling probes sea level change

Media Release
15 November 2009

Seabed drilling probes sea level change

An international team of 33 scientists will spend the next two months drilling beneath the seabed off the Canterbury coast in a bid to pin down the link between climate and sea level changes over the last 35 million years.

The drilling ship JOIDES Resolution is transiting from Townsville to New Zealand and will berth in Wellington on November 16 for a brief refuelling stop before heading south.

When it arrives off the coast of Canterbury later this week it will position itself in water depths of 80m to 400m and collect sediment cores to depths of 1800m beneath the sea floor at up to six sites across the continental shelf.

The expedition is part of the Integrated Ocean Drilling Program (IODP), an international consortium of scientific organisations from 24 countries that operates two drilling ships to probe beneath the seafloor for answers to questions on global change, ocean evolution, geological processes and the nature of life beneath the sea floor.

New Zealand has recently joined the program as part of an Australian-New Zealand consortium and has three geoscientists on the ship.

Dr Greg Browne from GNS Science, who helped plan the expedition, will be working within a team of eight sedimentologists. They have the job of translating subtle changes in the amount of sand, mud, and limestone into a record of sea level change.

Dr Martin Crundwell, also from GNS Science, joins a team of seven micropalentologists identifying the microscopic fossils recovered in the sediment cores. Remains of these tiny marine organisms are used to determine the age of the sediments and the environmental conditions that existed when the organisms were alive.

Dr Kirsty Tinto, from the University of Otago, is one of two paleomagnetists who will analyse the magnetic properties of the sediment cores to identify boundaries across which the magnetic polarity is reversed. These reversals reflect moments in Earth’s past when its magnetic field ‘flipped’. Measurements on the core produce a magnetic ‘bar code’ that is used to match the core with the well-dated record of past changes in Earths magnetic polarity.
Scientists have reasonably good records of the Earth's temperature fluctuations during the past 30 million years. But the understanding of the links between global temperatures, polar ice volumes and changes in sea level is incomplete. Scientists anticipate the drill cores recovered off the Canterbury coast will shed light on this.

The JOIDES Resolution will return to Wellington in early January 2010 to collect provisions and take on a new team of scientists, including Dr Robert McKay from Victoria University of Wellington. The ship will then sail to Antarctica to collect sediment cores from the edge of continent. This study will investigate the link between past climate change and the behaviour of the Antarctic ice sheets and will help us understand the causes of sea-level changes identified in the cores collected from offshore Canterbury.

The ship will spend several days in Wellington in early January between the two expeditions. While berthed in Wellington there will be guided tours of the JOIDES Resolution for invited guests and the media. A two-week holiday programme linked to the visit will be offered for children aged 12 and older.

New Zealand participation in IODP is funded by GNS Science, Victoria University of Wellington and the Universities of Otago,

For more information go to: NZ Ocean Drilling Programme: http://drill.gns.cri.nz/nzodp/index.html Research ship JOIDES Resolution: http://joidesresolution.org/ Integrated Ocean Drilling Program: http://www.iodp.org/

ENDS

© Scoop Media