sail-world.com
 
 
News Home Cruising Photo Gallery Video Gallery

 

Sail-World.com : New discovery from Antarctica’s ‘ghost mountains’

New discovery from Antarctica’s ‘ghost mountains’

'AGAP team'    British Antarctic Survey ©    Click Here to view large photo

The discovery of numerous large ice structures within Antarctica’s Dome A region, the site of the buried ‘ghost mountains’, reveals new understanding about ice sheet growth and movement that is essential for predicting how the ice sheet may change as the Earth’s climate warms.

Reporting this week in the journal Science a six-nation group of scientists studying the Gamburtsev Subglacial Mountains describe how these remarkable structures form. Typically ice sheets grow when layers of snow are deposited on the surface, but the researchers found startling new evidence of growth at the base. Widespread re-freezing of large volumes of water to the underside of the ice sheet modifies its structure. In some places this process can account for up to half the ice sheet’s thickness, and the growth caused by refreezing may be comparable to that occurring at the surface.


The enigmatic Gamburtsev Subglacial Mountains lie buried beneath as much as 3 km (two and a half miles) of ice. An international team mounted an ambitious field campaign to investigate the ice sheet and what lies beneath during the International Polar Year (2007-09).

Lead Author, Dr Robin Bell of Columbia University’s Lamont-Doherty Earth Observatory says, 'We usually think of ice sheets like cakes - one layer at a time added from the top. This is like someone injected a layer of frosting at the bottom - a really thick layer. Water has always been known to be important to ice sheet dynamics, but mostly as a lubricant. As ice sheets change, we want to predict how they will change. Our results show that models must include water beneath.'

Co-Author Dr Fausto Ferraccioli, from British Antarctic Survey says, 'This International Polar Year study provides a unique view on the interactions between subglacial water and ice sheet structure in East Antarctica. Understanding these interactions is critical for the search for the oldest ice and also to better comprehend subglacial environments and ice sheet dynamics. Incorporating these processes into models will enable more accurate predictions of ice sheet response to global warming and its impact on future sea-level rise'.

The refrozen structures form because the vast Antarctic ice sheet acts like blanket trapping geothermal heat from the Earth beneath. This heat, combined with the great pressure from the overlying ice allows ice to melt at the base. When under the ice this water can be pushed uphill, towards mountain ridges where the ice sheet is thinner. This thinner and colder ice refreezes the water, creating the spectacular structures observed close to the base of the ice sheet.

The researchers theorize that this process explains the re-frozen structures appearing at the heads of valleys beneath the ice sheet. This new ice at the base pushes older ice closer to the surface, making the ancient layered record of climate embedded in the ice easier for researchers to reach.

Bell continues, 'When we first saw these [refrozen] ice structures in the field, we thought they looked like beehives and were worried they were an error in the data. As they were seen on many lines, it became clear that they were real. We did not think that water moving through ancient river valleys beneath more than one mile of ice would alter the basic structure of the ice sheet.'

The refrozen ice accounts for up to 24% of the area of the ice sheet base around Dome A, the top of the East Antarctic ice sheet. The scientists suggest that this process has been going on since East Antarctica became encased in a large ice sheet 32 million years ago. Researchers now will now look into how refreezing affects the margins of the Antarctic and Greenland ice sheets, where the most rapid change is occurring.



British Antarctic Survey website




by British Antarctic Survey and Lamont-Doherty Observ

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=81064

2:41 PM Sun 6 Mar 2011 GMT






Click here for printer friendly version
Click here to send us feedback or comments about this story.


News - USA and the World



















The first annual WetaFresh is a big success by Tim Wieringa, Muskegon, MI


















Techno 293 Worlds - France and Italy claim titles by International Windsurfing Association,














420 World Championship - Singapore and Spain out front by 420 International Class Association,
















Round Britain and Ireland Race 2014 - Tactics, endurance, achievement
Alpari World Match Racing Tour moves on to Poland + Video
2014 ISAF Sailing World Cup final qualification system published
Chicago Yacht Club Race to Mackinac - Karma Sailing Group wins
Red Bull 49erFX: Easing into the Olympic scene at Rio
Kempe thrilled to invite himself to Gold Cup party
2014 420 World Championships - Singapore wins Day 2 race
Lightning strikes cut short CFJ Nationals
Etchells Invitational Cup - Girls on top in Cowes
National Sailing Hall of Fame reveals inductees
J/111 North American Championship - Wind Czar victorious
Sevenstar Round Britain and Ireland Race sets off August 10th
PWA Fuerteventura Grand Slam - Antoine Albeau victorious on day 5
Snipe Western Hemisphere and Orient Championship headed for San Diego
WPA Championships - Kids race divisions offered
New Clever Pig launched by US Sailing
America's Cup: Group agrees to co-operate in London Meeting
Copa del Rey Mapfre - Build-up reveals some remarkable enthusiasm
Marblehead NOOD Regatta - Images by Leighton O'Connor
America's Cup: Two AC72 skippers discuss Foiling Moths and the Cup
RS Feva World Championship - Brilliant sailing on day 2   
America's Cup: Alameda makes overtures on Venue hosting for San Fran *Feature   
Cape Panwa Hotel Phuket Race Week 2014 - Relishing a challenge   
Edgartown Race Weekend - BBBR and Round-the-Island Race winners named   
Etchells Invitational Cup - Aussies take early lead in Cowes   
PWA Fuerteventura Grand Slam - Antoine Albeau strikes back on day 4   
Aquece Rio – International Sailing Regatta - All set for test event   
ISAF World Sailing Rankings for 28 July 2014   
29er World Championship - All set in Kingston   
ORC World Championship - Third Course area opens for huge fleet   
Day one of the Allen RS Feva World Championships   
Anna Tunnicliffe: Final two days of the 2014 Reebok CrossFit Games   
Joachim Aschenbrenner takes gold at ISAF Youth Match Race Worlds 2014   
Maxi Soh scores double wins in CMRC Summer Doubleheader   
29er World Championship opening ceremonies in Confederation Park   
PWA Fuerteventura Grand Slam - Action resumes on day 3   
Vic-Maui Yacht Race - Polishing the silverware   
Land Rover Sydney Gold Coast Yacht Race Start 2014 VIDEO   
Laser Radial Men’s World Championship 2014- Final day   
2014 Pacific Cup - Scarlet Runner wins   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  http://www.sail-world.com/event_images/image/RSS-Icon.png

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL WAS US
LocalAds   DE  ES  FR  IT