It was almost as if subglacial lakes were destined to remain hidden. Early seismic data was misinterpreted. Records were destroyed in fires. Equipment failed just as teams driving hundreds of miles reached the edge of the lakes. Some tantalizing hints suggested there might be water under the ice sheet, but it was not until we had the perspective of looking at the ice sheet from space that the large lakes became evident. Detailed measurements of the height of the ice surface provided the first real opportunity to "see the lakes". The surface of most of the ice on the sheet is rough as it flows over the hills and mountains below. Just as in winter a woodland lake will be an expanse of horizontal floating ice continuing to the horizon, the ice above a subglacial lake floats and the ice surface is very flat.
These lakes exist because the thick ice acts as an insulating blanket, capturing the heat emerging from the Earth's interior. The temperature at the top of an ice sheet is minus 50 degrees Fahrenheit (–45.5 degrees Celsius), while at the bottom it is a positively warm at 28.4 degrees F (–2 degrees C)—very close to the melting point of ice. The pressure of the overlying ice lowers the melting temperature of ice a bit, but the main reason for the warm temperatures is primarily the natural geothermal gradient.
Twenty-five years ago, no one would have believed that there could be lakes under the . Ten years ago, scientists thought these lakes were stagnant and isolated from one another. Today, we know that subglacial lakes are connected under the ice through a maze of plumbing, and that this connectivity can subject them to rapid drainage akin to pulling the plug from a bathtub, allowing water to drain from one lake into another. Draining water from subglacial lakes may contribute to the onset of ice streams, accelerating their movement toward the continental edges, where they rest against the surrounding ocean water.
In East Antarctica, the largest subglacial lakes are found in the foothills of the Gamburtsev Mountains. Lake Vostok, the size of Lake Ontario, and two other large deep lakes mark the eastern edge of the mountainous province. On the western edge, four large lakes are linked to the onset of the rapid flow of the ice sheet. Using airborne imaging technologies, we will collect the first data that may tell us why these large lakes are found in the Gamburtsev Foothills. We are trying to understand how the subglacial lake system may influence the flow of polar ice toward the global oceans. This International Polar Year program (AGAP) to study the Gamburtsev Mountain Province will allow us to gather critical information on these lakes and help connect the dots on their role in Antarctic glacial plumbing.
Exploring Hidden Terrains
If the East Antarctic Ice Sheet were dropped on top of the lower 48 U.S. states, every single town would be covered. Only a few mountain peaks would be exposed. Satellites cannot see through the ice sheets. Studying mountains and lakes covered by a thick blanket of ice is a challenge.
Fifty years ago, scientists had no good estimate of the thickness of the Antarctic ice sheet. At the beginning of the last IPY, using oil industry technology, convoys of tracked snow vehicles from many nations set out across Antarctica. The convoys, or traverses, stopped every 50 miles (80 kilometers) to lay sensitive recording devices (geophones), drill a 150-foot (45-meter) hole, and set off small explosive charges. The explosions would send a fountain of snow into the air and energy deep into the ice sheet. The downward propagating wave would bounce off the hills and valleys at the bottom. The return echo would be recorded by the geophone. Each explosion produced one measurement of ice thickness.
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12 Comments
Add Comment"Two teams will build the camps, one on the north side and the other on the south side of the mountain range. The heavy equipment and fuel for the southern camp will be delivered by a surface traverse that will pass first through the South Pole."
Reply | Report Abuse | Link to thisIf one camp is across the south pole from the other camp, won't both of them be on the north side?
Our school will be following along! Some 8th grade students have decided to research your team's work in the Antarctic for their polar project. You have already inspired the next generation! Thank you!
Reply | Report Abuse | Link to thisHey! Where are all the liberals who think Space is a great waste of money? You know, the "We have to many problems here on Earth" people? The "if we only had that nickel NASA spends ..." Come on guys be consistent. This is a great waste of money. Government should NOT give welfare to 'science' unless it directly supports welfare programs to people OR unless it directly supports mismanagement of money and resources, to achieve an uncertain goal based on dubious politicized 'science' so the government can step in to 'offer' itself as the solution. Like Health Care and Global Warming ... uh ... Climate Change (can't have a changing climate can we!). The proper role of science is to support government expansion.
Reply | Report Abuse | Link to thisFor more information on the International Polar Year 2007-8, and ways that people all around the world can get involved, talk to scientists in the polar regions directly, and learn more about these critical regions, please visit www.ipy.org.
Reply | Report Abuse | Link to thisGreat Sheila if you want patches for your 8th graders let me know - e-mail me at mkt@ldeo.columbia.edu
Reply | Report Abuse | Link to thisThe reference to North and South camps is in relation to their placement relative to the subglacial mountain range - one is north and one is south of it.
Reply | Report Abuse | Link to thisI'm one of the ..uh. grunts / meteorology techs / mountaineers on this project. I've got a blog at http://patriotearth.blogspot.com where I'll be posting pics when I get back in January, in case you're interested in seeing some of the grittier sides of Antarctic field work. ;-)
Reply | Report Abuse | Link to thisA map sure would be helpful to understand the logistics and the scale of this project. As mentioned in the article, maps are often distorted or minimized, and missing mountains aren't likely to be noted even if one found a good map. So as a reference point, if you draw a line from the south camp to the north camp and continue it on, what is the first country the line would hit or what longitude would it fall on? And would you point readers to a good map with the 'missing mountains' on it?
Reply | Report Abuse | Link to thisHow much geologic mapping has occurred over the past several decades in Antartica? Is there a geologic map of the continet available for "public" viewing, showing the data that is currently available? Have different research teams from different countries shared information to produce a single map showing all of the information known to date? In the mapping of rock types, what is the standard that is used for designating different strata? Are there any exposed areas of limestone on the Antarctic continent?
Reply | Report Abuse | Link to thisGreat work, Robin, & thanks also for sharing your experience Ian. I've indulged in very romantic ideas of the noble few dedicating their lives to pure research and life on the ice, but after reading up on firsthand accounts, am now reconsidering these dreams...
Reply | Report Abuse | Link to thisPossible explanations as to the mountains .
Reply | Report Abuse | Link to thishttp://www.continuitystudios.net/guestvid.html
http://www.nealadams.com/nmu.html
For an interesting interview of Robin Bell on the subject of the Gamburtsev Mountains: http://www.sciencepoles.org/index.php?/articles_interviews/gamburtsev_dr_robin_bell_on_antarcticas_ghostly_mountains/&uid=1311
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