UNDER THE ICE: Scientists have detected a deep rift valley, similar in size to the Grand Canyon, beneath the ice of West Antarctica.
Image: flickr/NASA Goddard Photo and Video
A massive rift valley that lies under a portion of the West Antarctic ice sheet could be speeding its melt, according to scientists who compared their discovery to a frozen Grand Canyon.
The subglacial basin underneath the Ferrigno Ice Stream is up to a mile deep in places. It lies in West Antarctica, a region where thinning glaciers shed so much ice they contribute 10 percent of global sea-level rise.
For scientists, news of the ice-filled rift valley goes beyond novelty. They hope the discovery will help them understand how the contours of the bedrock that underlies most of Antarctica's ice affects where, and how quickly, that ice will melt as the climate changes.
Rob Bingham, the University of Aberdeen glaciologist who led the new study, said the rift appears to connect inland portions of the Antarctic ice sheet to the ocean.
That is significant because a recent British Antarctic Survey study concluded that influxes of warm ocean water are driving ice loss in West Antarctica. The warm currents eat at the floating tongues of ice that help slow the seaward flow of glaciers sitting on Antarctic bedrock.
When those ice tongues disappear, the ice on land speeds up and thins as it slides to the coast and calves icebergs.
The discovery of the new rift "ties in so well with the signal of ice thinning," Bingham said. "There is a clear correspondence with this feature that was created over thousands of years and this phenomenon that has been happening over 20 years."
He and several colleagues from the British Antarctic Survey published the new findings yesterday in the journal Nature.
Studying the two extremes
Bingham said the topography in and around the Ferrigno Ice Stream appears to be similar to bedrock configurations that underlie two much-studied and rapidly thinning glaciers in West Antarctica, Pine Island and Thwaites.
"Pine Island and Thwaites are the absolute extremes," he said. "They are the ones experiencing the most thinning, whose loss would cause the greatest impact on sea level." (Pine Island Glacier, Antarctica's speediest, sheds 46 billion metric tons of ice per year.)
Though the Ferrigno Ice Stream isn't moving as quickly or shedding as much ice as Pine Island, its melting may still be at a more advanced stage.
"It doesn't have an ice shelf in front of it," Bingham said of the ice stream. "We think there was an ice shelf there, and it has been removed by a warm sea. ... It has potentially experienced warming before Pine Island and Thwaites did."
The new study marks the first time scientists have visited Ferrigno since the early 1960s, when the U.S. government sponsored a series of overland traverses to explore Antarctica's vast expanse of ice. Today, the Ferrigno Ice Stream lies hundreds of miles from the nearest science base.
"When you mount a mission anywhere in this region of West Antarctica, you're talking very serious logistics," Bingham said. "It's hard to get planes into this area. The weather is not hospitable."
But satellite data showing that the ice stream is one of the areas where the edges of the Antarctic ice sheet is thinning drew his attention.
An ancient network
Bingham, with help from the British Antarctic Survey, traveled south during the Antarctic summer of 2009-2010 to survey the area. He and an assistant spent 10 weeks mapping the hidden world beneath the ice stream using a Ski-Doo pulling ground-penetrating radar.
They supplemented that data with additional ice-thickness measurements gathered by NASA's Operation IceBridge project, which uses specially outfitted aircraft to monitor polar ice.
The magnitude of what lay under the Ferrigno Ice Stream's smooth surface soon became apparent.
See what we're tweeting about
13 Comments
Add CommentHow can you have a 'West Antarctica'? It would seem like the term couldn't apply at the bottom of the earth and more than 'North Antarctica'.
Reply | Report Abuse | Link to thisTake a look at http://www.mapsofworld.com/lat_long/antarctica-lat-long.html. The 0/180 line of longitude divides the continent into east and west. That's how.
Reply | Report Abuse | Link to thisMy God, we have now discovered that ICE melts. WOW what an impressive new fact - oh I guess that means no glaciers will be returning to North America anytime soon?
Reply | Report Abuse | Link to thisWhat a waste of time and money - IMO
to posters 1 & 2, kind of like the reference that he traveled south;-)
Reply | Report Abuse | Link to thisto profitsup...I guess your name kind of says it all...
All this could turn out to be a short cycle of warmth followed by a return to more normal temperatures.
Reply | Report Abuse | Link to thisThough it can just as well be the harbinger of a very
long slow warming period. Or there may be life at the
poles after all.
Wow... that's fantastic. I just had a look at the antarctic map. Amazing.
Reply | Report Abuse | Link to thisSeeing as the circumference of the planet is 40000km at the equator and supposedly zero to very small at the poles so therefore the friction heat produced is far more when 40000km is traveled each 24 hours through the air against say the 10km in 24 hours at the poles. Agreed?
No, Mr. Palmer, that is nonsense.
Reply | Report Abuse | Link to thisThe Earth's atmosphere (and its oceans) rotate right along with the solid Earth.
Didn't you know that people live right along the Equator in South America, Africa, and Indonesia, and a supersonic wind does not blow them away? We do not get such winds from the rotation in North America, Australia, Europe, or Asia, either.
What made you write the number 40,000 km w/o a blank or a comma. It is always written with a space just like 25,000 miles and 240 volts, despite what some lazy writers do overseas. By the way, the use of the period for the decimal point was introduced by the Scottish mathematician John Napier, who also discovered the logarithm, several centuries ago, so why should continental Europeans argue with that? Do they despise the British so much?
For this deep historical reason, Britons, Americans, Canadians, etc., write numbers like 11,776.54 and the meaning is clear. Why not confirm to this practice, which was started by the great John Napier of Scotland?
I agree that terms like "West Antarctica" are silly. If you get into Antarctica and you head west, you just go around in a big circle and then arrive back at your starting point. The same applies for "East Antarctica".
Reply | Report Abuse | Link to thisIn contrast, when you start anywhere in the mainland of The Americas and drive west (such as in a Jeep), you reach the Pacific Ocean in the west and you cannot go any farther. Likewise, do the same in most of Eurasia, and you go west all the way to the Atlantic Ocean. (Otherwise, you could reach the Indian Ocean, such as from India or Arabia, or reach the Arctic Ocean.) In Australia, you reach the Indian Ocean, and in the mainland of Africa, you reach the Atlantic Ocean.
In all of these cases, you reach the West Coast of something, and you cannot drive or walk any farther.
As for dividing Antarctica depending on whether you are in the Eastern Hemisphere of the Western Hemisphere, why should this be done? Why should Australia be treated differently from the other five continents? (Eurasia, Africa, Australia, North America, and South America?) The definitions of such places as Western Europe, West Africa, Western North America, and Western Australia are all clear and obvious.
Whenever those savants and scholars mean "Antarctica in the Western Hemisphere", they should say so, rather than using obscure terms like West Antarctica".
D.A.W.
Sorry, I mistyped. I meant to type "Why should Antarctica be treated differently from the other five continents?"
Reply | Report Abuse | Link to thisProfitsup: Why do you even bother coming to this site to read anything? You obviously do not want to learn anything or to support anyone who does. You just want to make snide and ignorant remarks, and I assure you that there are far better places and ways to do that. To begin with, just write them up as e-mails and send them to yourself. Away with you. You do not know anything about ice caps, and you do not want to learn anything about them either.
Reply | Report Abuse | Link to thisYour concerns should be about catching bear, skinning bear, roasting bear blubber, eating bear fat.
D.A.W.
Calling this geographical feature a "rift valley" is very misleading. Other sources in the media list this CANYON as being about 100 kilometers long.
Reply | Report Abuse | Link to thisThe Great Rift Valley of East Africa is about 2,000 kilometers long, so that canyon in Antarctica is peanuts compared with the Great Rift Valley.
By the way, there is an extension of the Great Rift Valley that extends into Asia. It forms the Gulf of Aqaba and the large, deep valley of the Dead Sea, too.
D.A.W.
Calling this geographical feature a "rift valley" is very misleading. Other sources in the media list this CANYON as being about 100 kilometers long.
Reply | Report Abuse | Link to thisThe Great Rift Valley of East Africa is about 2,000 kilometers long, so that canyon in Antarctica is peanuts compared with the Great Rift Valley.
By the way, there is an extension of the Great Rift Valley that extends into Asia. It forms the Gulf of Aqaba and the large, deep valley of the Dead Sea, too.
D.A.W.
Oh! How interesting! How interesting! I am more impressed by the interchange of ideas in the commentaries than in the article(that is also good) itself!
Reply | Report Abuse | Link to this