Please select your home edition
Edition
Barz Optics - Floaters

New discovery from Antarctica’s ‘ghost mountains’

by British Antarctic Survey and Lamont-Doherty Observ on 7 Mar 2011
AGAP team British Antarctic Survey © http://www.antarctica.ac.uk
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.


AGAP © British Antarctic Survey  http://www.antarctica.ac.uk
AGAP © British Antarctic Survey
British Antarctic Survey website
Barz Optics - FloatersT Clewring J-classNaiad

Related Articles

Kids Polarised Sunglasses from Barz Optics
Barz Optics have developed a quality range of junior polarised sunglasses ideal for sailing and fishing. Barz Optics have developed a quality range of junior polarised sunglasses ideal for sailing and fishing. Each pair are supplied with a neoprene case and sunglass retainer.
Posted on 4 Aug
Reducing weight aloft with composite backstays
Reducing weight aloft is one of the most cost effective ways of increasing your boat speed and performance. Reducing weight aloft is one of the most cost effective ways of increasing your boat speed and performance. Every kilogram you take out of the rig is roughly equivalent to 4kg added to the bottom of your keel!
Posted on 26 Jul
Free $US3,000 Carbon Vang with SouthernFurl boom orders in July
Southern Spars is giving a free carbon vang - valued at US$3,000 - with SouthernFurl in-boom furlers ordered in July Southern Spars is giving away a free carbon vang - valued at US$3,000 - with all of their SouthernFurl in-boom furlers ordered in July. Carbon gas vangs make a great addition to the furling boom package, though if you’d prefer to keep your existing one, Southern Spars will offer you a 5% discount on the price of your boom instead.
Posted on 29 Jun
Newport Bermuda Race - High Noon takes honours
As the Newport Bermuda Race fleet rushed to the finish line on Monday in the wake of the first-to-finish boat, As the Newport Bermuda Race fleet rushed to the finish line on Monday in the wake of the first-to-finish boat, the powerful 100-foot grand prix Comanche, to the surprise of many they were led by an unusual boat and crew. High Noon, at 41 feet, is fully 59 feet shorter than Comanche and tens of feet shorter than many other entries.
Posted on 22 Jun
Platino recovery - Family confirms that tug has made rendezvous
Reports in social media say a salvage tug has made a rendezvous with the Platino earlier than expected. Reports in social media by family and friends of Nick Saull, the crew member killed during a catastrophic incident abroad the 66ft yacht Platino say the salvage tug which left on Tuesday night has made the rendezvous earlier than expected. The Facebook report says the tug, Sea Pelican, arrived on Friday morning, the weather in the area has eased and with a more favorable outlook.
Posted on 16 Jun
Royal Queensland Yacht Squadron to ban bottled water
Approval has been given to create a ban on bottled water that comes in plastic containers. The RQYS Management Committee has confirmed that approval has been given to create a ban on bottled water that comes in plastic containers. This will place the club as a leader in environmental impact management in Australia and around the world. The Royal Hong Kong Yacht Club earlier this year did likewise. Who’s next?
Posted on 16 Jun
SouthernFurl In-Boom furling systems withstand Sydney Hobart test
Southern Spars design team have developed the SouthernFurl Boom smaller budgets and yachts from 35-70 feet. Have you ever scared your family when you got stuck with too much sail up when you should be reefed? Southern Spars’ range of SouthernFurl booms are the answer – letting you reduce sail quickly and easily without leaving the safety of the cockpit.
Posted on 23 May
2016 Garda Trentino Olympic Week - Day 4
Garda Trentino Olympic Week 2016 draws near to the conclusion: the weather once again proves difficult. Garda Trentino Olympic Week 2016 draws near to the conclusion: the weather once again proves difficult. Tomorrow the medal race is scheduled for the Lasers and another two races for the three paralympic classes.
Posted on 13 May
CCA presents RCC Award to Scott and Mary Flanders
CCA has announced that Scott and Mary Flanders are the recipients of the organization’s 2015 Royal Cruising Club Trophy. The Cruising Club of America (CCA) has announced that Scott and Mary Flanders are the recipients of the organization’s 2015 Royal Cruising Club Trophy.
Posted on 22 Apr
Cyclone Winston Relief Fund – Help the people of Fiji
Sea Mercy is sending volunteer fleet of small and large vessels, loaded with shelter, food and medical supplies to Fiji. Sea Mercy is once again sending our volunteer fleet of small and large vessels, loaded with shelter, food, water and medical supplies and teams to Fiji.
Posted on 27 Feb