Hidden beneath thousands of feet of Antarctic ice lies information about Earth's climate a million years ago and clues to how rapidly future sea levels will rise because of global warming.
Now University of Minnesota Duluth researcher John Goodge is involved in the effort to develop a drilling system capable of quickly boring to those clues. The National Science Foundation has given Goodge's team a $1.3 million grant to design a "Rapid Access Ice Drilling" system, or RAID, and to develop a construction budget and plans for deploying and operating the system.
Once it's built, RAID will be operated jointly by UMD and the Ice Drilling Program Office at Dartmouth College.
"The interdisciplinary research community has long wished for an access drill that could quickly drill through the thick ice of East Antarctica for scientific investigations, and the proposed RAID drill shows great promise for addressing that need," Mary R. Albert, Ice Drilling Program Office executive director, said.
Using drill systems to obtain ice cores in Antarctica and Greenland isn't new. But many of the systems are huge -- taking perhaps several years to reach bedrock while collecting a top-to-bottom core of ice several inches in diameter.
RAID, by contrast, may drill a smaller hole through two miles of ice in a week. It probably will collect cores about two inches in diameter only after it reaches the deepest -- and hence, oldest -- ice.
"Our idea is to get down to (the) deepest parts of the ice sheets, just skip all the upper stuff," Goodge, a geological sciences professor, said. "When we get to a depth where we think the oldest ice is, we will start coring."
One goal is find ice formed more than 1 million years ago, when Earth went through a major climate change. Gases trapped in the ice when it formed can give researchers clues about the change.
Currently, the oldest ice found dates back 750,000 years.
The drill won't stop in the ice. Researchers plan to collect cores from where ice and earth meet, as well as from the top 75 to 150 feet of bedrock.
"Because I am a basement geologist, I want to drill into the bedrock below and get samples of the geology under the ice," Goodge said. "That is important because only 2 percent of Antarctica is exposed; the rest is covered by snow and ice."
Goodge has made 11 trips to Antarctica to help build a better geologic picture of the continent and its connection to North America: during a 2005 trip, Goodge found a rock that is helping researchers reconstruct the look of a supercontinent that existed more than a billion years ago and links North America and Antarctica.
At 5.4 million square miles, Antarctica is 1.4 times the size of the U.S. Its ice covering averages at least one mile in depth.
RAID also will help determine how securely the ice is connected to the underlying rock, whether it's firmly frozen to rock or sliding over a layer of soft and wet rubble.
"The stability of the ice sheet is clearly important for our future as we experience a continuing warming of our global climate," Goodge said. Glaciers less solidly anchored to rock may advance to the sea faster, accelerating rising sea levels and coastal flooding.
Boring smaller holes not only will allow RAID to drill quickly; it also means the system is lighter and more mobile than drill rigs using larger pipes. It may be able to complete several holes in different locations during the three-month field season in Antarctica. Each borehole will be kept open so researchers can study heat flow and ice flow over several years.
Goodge's team hopes to develop scale drawings and an estimated cost for building RAID this year. If the National Science Foundation authorizes construction, a completed drilling rig could be available for testing in January 2015 and shipment to Antarctica in early 2016.
Early estimates put the rig's cost at between $2 million and $5 million.
In addition to UMD and the NSF, the project's partners include Scripps Institution of Oceanography at the University of California-San Diego, DOSECC Exploration Services and Lockheed Martin Corp.