Antarctic Scientific Drilling Project Underway

Antarctic Scientific Drilling Project Gets Underway

Scientists and engineers head south this week to prepare for the most challenging sub-ice drilling project yet attempted in Antarctica.

The multinational project, being led by New Zealand and the United States, will operate at a remote camp more than 100km from Scott Base on the Ross Ice Shelf.

The leading New Zealand organisations are Victoria University of Wellington, GNS Science, and Antarctica New Zealand. Scientists from NIWA and the University of Otago are also involved.

The programme for this summer will consist of a range of activities to prepare for another leg of the ANDRILL drilling project planned for the 2013-14 summer season at Coulman High, 150km northeast of Scott Base.

ANDRILL’s previous drilling projects, on the McMurdo Ice Shelf in 2006 and 2007, recovered the two deepest rock cores in Antarctica – 1285m and 1138m beneath the sea floor – containing a climate history of the continent going back 20 million years.

The project at Coulman High is targeting rock and sediment from an older era when atmospheric greenhouse gases were up to three times higher than pre-industrial levels, or similar to what some climate models project for the end of this century.

When the deep drilling gets underway in 2013/14, the drill will need to pass through 250m of ice, 650m of seawater and then about 1000m into the seabed. The ice shelf is moving at about 2m-a-day, which will put stress on the drilling equipment and drill pipe.

The rate of ice flow is about 10 times faster than at the two previous ANDRILL drilling sites. It will give drillers about a 20-day window before the drill pipes bend to the point where drilling could become impractical.

Lead New Zealand scientist, Dr Richard Levy from GNS Science, says that scientists hope to collect drill core that shows the transition from an ice-free continent, to a time when large Antarctic ice sheets had developed, about 34 million years ago.

“It’s a continuation of previous ANDRILL projects and takes us further back in time to periods when global temperatures were about 6 degrees Celsius warmer than today,” Dr Levy said.

To improve the knowledge of ice sheet behaviour and the likely impact on sea level, scientists need to collect more geological information from drilling, which would be used to further develop computer-generated climate, ice, and ocean models.

Logistics Manager Tamsin Falconer, of Victoria University’s Antarctic Research Centre, explained that this summer’s work is critical for preparing for future drilling.

"Before we embark on the drilling, we need to collect a wide range of environmental information about the site to ensure the drillers and engineers are appropriately prepared.”

One of the first big jobs will be to move 20 shipping containers of equipment from Scott Base to the Coulman High site. The equipment includes the hot-water drill, living quarters for about a dozen people, and kitchen facilities.

The containers will be towed by tractor on a 15-hour journey. The drilling site and camp at Coulman High is located about 10km back from the edge of the ice shelf, which has a 40m sheer face to the Ross Sea. By mid-November the team will use the hot-water drill to melt the first of four holes through the 250m-thick ice.

NIWA scientists will work with US colleagues to deploy oceanographic instruments through the first two holes to measure ocean and tidal currents, temperature and salinity of the water. The instruments will be lowered through a hole in the 250m thick ice shelf into the ocean below, frozen in place for two months, and then recovered using a hot water drill.

Professor Gary Wilson, from the University of Otago, will work with US and New Zealand students on a gravity survey aimed at understanding more about the geology of the ocean basin beneath the ice. This study will provide valuable regional context for the future drill holes.

A 25cm-diameter torpedo-like remotely operated vehicle will be lowered through the third hole. Named SCINI – Submersible Capable of Under Ice Navigation and Imaging – the ROV was developed by Moss Landing Marine Laboratories in California. It will capture video from under the ice and may eventually be used near the seafloor to support the drilling in 2013-14.

At the fourth drill hole, the scientists will deploy seismic equipment to image the rock layers to a depth of about 1500m below the seafloor to better understand the strata they will be drilling into.

Funding for this summer’s activities is coming from the Foundation for Research Science and Technology, Antarctica New Zealand, and the National Science Foundation in the US.

END

© Scoop Media