Featured Research

from universities, journals, and other organizations

Arctic Submarine Uncovers Evidence Of Giant, Ancient Ice Sheets

Date:
March 27, 2001
Source:
Ohio State University
Summary:
A scientific expedition on a submarine in the Arctic has found the footprints of ancient floating ice sheets -- possibly the largest masses of ice ever to cover the earth's oceans.

COLUMBUS, Ohio - A scientific expedition on a submarine in the Arctic has found the footprints of ancient floating ice sheets -- possibly the largest masses of ice ever to cover the earth's oceans.

Studying the formation and demise of these ancient ice sheets may help scientists better understand Earth's climate changes and, in particular, predict whether the melting of today's polar ice could lead to catastrophic floods in the future.

Leonid Polyak, research scientist at Byrd Polar Research Center at Ohio State, and his colleagues obtained sonar images of the Arctic Ocean floor through a unique collaboration between the U.S. Navy and civilian scientists -- the Science Ice Exercises (SCICEX) program.

The results appear in the March 22 issue of the journal Nature. Polyak's collaborators, Margo Edwards of the University of Hawaii and Bernard Coakley of Tulane University, were chief scientists on the 1999 SCICEX mission, which took place aboard the nuclear submarine USS Hawkbill.

Within two separate, somewhat elevated regions of the Arctic Ocean floor -- the Lomonosov Ridge near the North Pole and the Chukchi Borderland near Alaska -- SCICEX images showed numerous features carved into the seafloor, including matching sets of parallel grooves and ridges. Sometime in the past, Polyak said, the bottom of a very massive floating ice sheet scraped across the seafloor in both areas -- almost 1 km below the water surface at the Lomonosov Ridge and more than 700 meters below the water surface at the Chukchi Borderland.

The sonar images clearly showed objects resembling rocks and other debris that may have once been dragged along the seafloor beneath the grounded ice.

"The results were just fantastic. We had hoped to find these seafloor features, but we hadn't expected to get such beautiful images," Polyak said.

"Such amazingly coherent sets of streamlined grooves and ridges could only be made by one thing - sliding ice," Polyak continued. And only a large ice sheet could carve such a broad sets of parallel features. Free-floating icebergs, he explained, carve random patterns into the seafloor.

The finding may bolster a theory held by some scientists: that one giant ice sheet covered the entire Arctic periodically during the ice ages that occurred between 10,000 and 1.5 million years ago.

But Polyak thinks that the same features might have been carved by several large ice sheets instead of one. To find out for sure, he and his colleagues must determine whether the features formed at the same time in different regions of the Arctic Ocean. That's why the researchers have applied for funding to return to the Arctic on an icebreaker to take core samples from the seafloor.

"Even if there were two or more ice sheets instead of one, they were still giant structures of several hundred kilometers in length -- comparable to vast floating ice sheets observed today around Antarctica," said Polyak.

The researchers sought evidence of the ancient floating ice sheets in part to gather clues about the future of the West Antarctic Ice Sheet.

Unlike the ice in East Antarctica, the ice in West Antarctica is considered unstable because a large portion of it is floating. For years, scientists have debated whether a warming of earth's climate would cause the ice sheet in West Antarctica to collapse, which would cause sea levels to rise fast, possibly as high as 20 feet all over the world.

Polyak, a former biologist, says these findings also hold implications for other areas of science. For instance, he wonders how prehistoric life in the Arctic Ocean could have survived if the entire area was covered with an ice cap of several hundred meters in thickness.

This question is related to a recently proposed theory called "snowball Earth," Polyak said. The theory holds that ice completely covered the Earth's oceans at some time between 550 and 750 million years ago, drastically affecting the evolution of primitive life.

"Who knows - maybe clarifying the history of floating ice sheets in the Arctic Ocean will even help us understand the evolution of ice-bound planets, such as Jupiter's moon Europa," he said.


Story Source:

The above story is based on materials provided by Ohio State University. Note: Materials may be edited for content and length.


Cite This Page:

Ohio State University. "Arctic Submarine Uncovers Evidence Of Giant, Ancient Ice Sheets." ScienceDaily. ScienceDaily, 27 March 2001. <www.sciencedaily.com/releases/2001/03/010322075843.htm>.
Ohio State University. (2001, March 27). Arctic Submarine Uncovers Evidence Of Giant, Ancient Ice Sheets. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/2001/03/010322075843.htm
Ohio State University. "Arctic Submarine Uncovers Evidence Of Giant, Ancient Ice Sheets." ScienceDaily. www.sciencedaily.com/releases/2001/03/010322075843.htm (accessed September 18, 2014).

Share This



More Earth & Climate News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Wildfires in CA Burn Forest Asunder

Raw: Wildfires in CA Burn Forest Asunder

AP (Sep. 18, 2014) An out-of-control Northern California wildfire has nearly 2,800 people from their homes as it continues to grow, authorities said Thursday. Authorities said a man has been arrested on suspicion of arson for starting the fire on Saturday. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins