


Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet and will be updating Scientific American readers regularly. Following are her initial thoughts as she--and her team--prepare to set off.

Courtesy of Robin Bell

International Polar Year--Why?
When I first heard of the concept of an International Polar Year (IPY), I rolled my eyes and gave one off those stupid "this is a boring idea" looks I had learned from my teenage son. How could an idea hatched by a military officer in the 1880s have any use in our age of hyper connectivity? The images from previous IPYs were filled with grimy men wrapped in parkas launching balloons, recording numbers in notebooks in small shacks and shooting off explosives. I simply could not see past the frost edges of the IPY parkas.

But then, something changed. It was July and I was sitting in the back of a steamy conference room in Shanghai, having just given a talk about lakes beneath two miles of ice. I was eager to see more of Shanghai on my first trip to China and had thought I might sneak out early until, that is, I heard Heinz Miller, a German glaciologist with a large mustache and an elflike twinkle in his eye, outline a bold concept for studying the interior of the East Antarctic Ice Sheet during the International Polar Year in 2007. I listened intently, like a teenager who suddenly realizes that calculus has some redeeming value. I began to see past the grimy faces and appreciate how global collaboration in the polar regions may produce remarkable insights that would otherwise be impossible. The only way we were ever going to understand the subglacial lakes was with an improved framework for international science in the polar regions. The IPY had the potential to provide this framework.

The first IPYs were planned by groups of scientists in close collaboration with the military. The current International Polar Year is a huge, interdisciplinary research program focusing on the polar regions from March 2007 to March 2009. In the modern age of science, this IPY has been the result of an almost organic effort of ideas bubbling up through the community. Working with a structure outlined by an international scoping committee, groups of scientists have come together and new programs have blossomed. This grassroots effort has entrained tens of thousands of scientists from 30 countries. Driven by the urgencies to understand the rapid change in the poles and reach the unexplored terrains, the past 18 months have seen an unprecedented level of international collaboration. Networks of instruments have been installed in both polar regions to monitor the changes in these remote areas. New records of past climate change have been recovered from the ice sheet and sediments. The theme of change is woven into science programs from anthropology to geophysics.

What are the results so far from the Fourth International Polar Year? Asking what we have learned is from the IPY is a little like asking baseball players the outcome of a game before the final inning. As with any large endeavor, there have been some setbacks: A key satellite crashed into the ocean shortly after launch, a helicopter has crashed with tragic loss of life, and one aircraft has been seriously damaged. The polar regions remain a challenge to work in. A most perplexing setback has been the crushing impact of the rapidly rising cost of fuel. Nations, large and small, have been forced to modify and delay their plans. Even the most carefully planned expeditions have been shortened or delayed. In general, most programs have been postponed, not canceled, and field programs planned of the IPY may just take a little longer.

While much of the discussion is still about aircraft, ships and traverse vehicles, some early results are emerging. Some results are scientific. Sediments cored from the edge of the Antarctic ice sheet indicate the West Antarctic Ice Sheet has grown and shrunk much more frequently than previously appreciated. Water beneath the ice sheets has been documented to move rapidly thought subglacial systems.

Some findings have to do with the fabric of science. A remarkable new network of young scientists has formed, new stations have been built, and new ways of collaborating have been developed. The next five years will see the blossoming of polar science and new data interpreted, delayed programs implemented, and a new generation of scientists actively working together to understand our planet. The polar regions are changing faster than any other place on the planet. The data sets acquired within the framework of the IPY, the new young networks of polar scholars, and the new infrastructure incorporated during the IPY will be crucial to advancing our understanding of these changing places over the coming decades.

Mystical Mountains
Last month, I opened an e-mail from Professor Emeritus Frank H. Pabodie of the Miskatonic University Engineering School. At a quick glance, the letter seemed legitimate—it was not from Africa and did not ask for my bank accounts. The letter touched my vanity by mentioning my other work so I read on. Then, in the third paragraph, it began to seem strange as the professor claimed to have been to East Antarctica prior to 1958. So I Googled Professor Pabodie. Oops! I had been reading a letter from a fictional character in an H. P. Lovecraft 1930 science fiction novella.

Apparently in 2008 this fictional character has a G-mail account and the university has a Web site.  Certainly H. P. Lovecraft, an early science fiction writer often compared to Edgar Allan Poe and Stephen King, had neither an e-mail address nor a Web site. In the 1920s Lovecraft was entranced by polar exploration. Admiral Byrd's first flights over Antarctica during the second polar year serve as the core of this novella, The Mountains of Madness. Professor Pabodie had been responsible for both the drilling devices and the heaters for the aircraft engines—both useful skills for our upcoming expedition.

While Pabodie claimed that the Gamburtsev Mountains had been discovered in by his expedition in the 1920s during the Second International Polar Year, it is more accurately attributed to the 1958 Soviet Antarctic expedition. This expedition was part of the Third International Polar Year, more widely called the International Geophysical Year. Shooting small explosives and recording the echoing energy, the expedition discovered a region of very thin ice in the center of the ice sheet—a mountain range entirely covered with ice. The expedition named the mountain range for Grigory Gamburtsev, a Soviet seismologist known for his efforts to predict earthquakes.

Even without the ghostly figures that inhabit Lovecraft's Antarctic mountain ranges, the Gamburtsev Mountains remain a mystery. They are completely covered with ice. Not a single craggy peak sticks up out of the ice sheet. They are tall—rising about 9,000 feet (2,700 meters) above the surrounding terrain. This means the Gamburtsev Mountains tower over the Appalachians and are about as high as the Alps—and hundreds of miles wide. If a well-maintained highway cut across them it would take the better part of a day to cross them. But, alas, there is no highway. Our team from six nations (which conceived of the Antarctic Gamburtsev Province, or AGAP, project as part of the Fourth IPY) has been working for eight years to figure out how to cross this remote terrain in three small scientifically equipped aircraft.

The real mystery of the Gamburtsev Mountains is their origin. Their presence in East Antarctica does not fit into our existing understanding of the geologic history of Antarctica. The Soviets' identification of these mountains was equivalent to an archeologist finding a fully suited astronaut inside a pyramid. Our current understanding of the sequence of geologic events in East Antarctica indicates the last evidence of large-scale tectonics was over 500 million years ago. Since then, East Antarctica has been basically a pretty boring place geologically. A 500-million-year-old mountain range old should have been worn away by now. Either the tectonic history of the Antarctic continent is wrong or something special about these mountain ranges has kept them from being eroded flat as a pancake.

It intriguing to think that the ice sheet has protected these mountains, but the ice sheet is only 35 million years old—the blink of an eye geologically. Maybe these mountains are much younger than we think or perhaps there is something about East Antarctica we do not know.  A mantle plume producing vast outpourings of lava like Hawaii or Iceland or maybe something new in the sliding about of the global plates. We should have a much better idea soon.

Our equipment is waiting in large aluminum boxes at McMurdo Station, the U.S. base perched on the flanks of a large active volcano. The Twin Otter aircraft will arrive tomorrow and the process of turning this rugged little commuter aircraft into an airborne imaging system on skis will begin. The British are awaiting the arrival of their aircraft, now slowly moving down the coast of South America. Soon we will be able to begin to answer questions about the roots of these mysterious mountains. While Lovecraft's team was terrified of alien beings, we must now worry about weather across an entire continent, equipment failures and altitude sickness.

Looking For a Lake
When you walk through the woods toward a lake, first you will often see ducks, loons, mergansers or other waterfowl flying intently towards the water. Soon you may notice marshy wetlands. Getting closer, you will hear the harsh rattling call of the kingfisher waiting to skewer a fish from the lake. As the trees thin, the horizon will open and the waters of the lake will stretch before you.

Walking toward a subglacial lake, there are far fewer clues. There are no trees to obscure your vision, only white snow and blue sky in every direction. The only hint of the lake will be when your colleague walking a quarter of a mile ahead suddenly disappears into a 15-foot- (4.6-meter-) deep moat. This 2.5-mile- (four-kilometer-) wide moat is the result of the ice sheet "sagging" as it goes afloat over the lake. There will be few other clues of the lake beneath your feet. The two miles (3.2 kilometers) of ice effectively hides the underlying terrain and the winged waterfowl have long ago fled these Antarctic lakes.

Appreciating a subglacial lake requires a little more distance to get perspective on the vast, apparently featureless ice surface. The first person to get a little distance was a Russian pilot, who transported scientists and engineers between the Soviet camps in East Antarctica in the 1950s. Staring out the window when the sun was low, he began to notice that there were large, extraordinarily flat places in the ice sheet. He catalogued these sites on the aviation maps with the hopes of writing a thesis on the phenomena upon his return to Moscow.  Unfortunately, he was killed in a crash and subglacial lakes were relegated to myth status in the polar community.

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.

Despite the very slow progress of these surface vehicles, one of the major discoveries from the International Geophysical Year resulted from the recordings of these explosions.  The scientists, bundled parkas, had to wait much longer than anticipated to record the echo from the ice sheet bottom. The reason: the ice was thicker than predicted. The East Antarctic Ice Sheet is up to 2.8 miles (4.5 kilometers) thick in places, enough ice to raise sea level globally 170 feet (52 meters) if it were to melt.

Driving over the ice sheet and setting off explosives every 50 miles is a slow process. Flying, even in a small airplane, is much faster. We will use two aircraft bristling with antennas and stuffed with instruments to collect new measurements of the ice sheet from the air, along with those taken from seismometers buried in the snow.

Mounted on the wings of the aircraft are eight antennas that transmit and receive 150 megahertz pulses to measure ice thickness. This radar system developed by the Center for Remote Sensing of Ice Sheets in Lawrence, Kan., has been developed specifically to image through the polar ice sheet. Similar to the seismic method, energy is transmitted through four of the antennas. The energy bounces back from the surface of the ice and the bottom of the ice sheet. We end up with thousands of measurements every second. This is a big improvement over 50 years ago when it took two to three days  to measure ice thickness.

To get a better idea of the surface of the ice sheet, my colleague Michael Studinger has installed near-infrared laser mounted below the floor in the aircraft. Within the nitrogen- filled container, the laser fires at a revolving mirror. When the mirror spins, the laser is aimed first to one side of the aircraft then to the other, so that the laser measures the ice surface right below the aircraft and out to the side. When we accurately position the aircraft, the laser measures the distance to within 2 inches (5 centimeters)! Testing in the hall in our office, we can see people dashing in between rooms.

Along with the ice-thickness data, we want to understand the origin of the Gamburtsev Mountains. To do this, we need to decode the fundamental structure of the crust and lithosphere beneath. It will be years, maybe decades, before anyone drills into the Gamburtsev Mountains, so we will use gravity, magnetics and seismic velocities to remotely probe the subglacial  terrains. The Earth's gravity field changes depending on the type of bedrock. A stronger gravity field means denser rock and a weaker gravity field means a less dense rock. An extremely accurate gravity meter will be mounted in the front of the aircraft. Measurements of variations in Earth's magnetic field will tell us about the nature of the underlying rocks. Some rocks are much more strongly magnetized than others. We will measure the changing magnetic field with cesium-based sensors mounted on the tip of the aircraft wings. Measurements of the magnetic field will tell us how magnetic the hidden rocks are.

The laser will measure the ice surface. The radar will measure the hidden topography. The gravity and magnetics will tell us about the makeup of the shallow part of the Earth—in general the crust. If we want to see deeper, we need a different method, A team lead by Doug Wiens from Washington University in St. Louis will install 26 seismometers spread hundreds of miles apart over the top of the Gamburtsev Mountains. Instead of shooting off explosives, the scientists will leave seismometers in place for months, recording distant earthquakes. These seismometers will be left in place for a year buried in the snow; they will be powered by the sun in the summer and by buried batteries through the long polar winter. The seismometers will record earthquakes from around the world to map the deeper structure beneath the mountain range. In the end, the seismic data will let us know how fast the energy from the global earthquakes travel and how warm or cold the Antarctic continent is at depths of hundreds of miles down.

Using this full suite of geophysical techniques, we will try within the next three months to build the first comprehensive cross-section of the largest ice sheet on our planet. In the world of modern imaging, we are accustomed to seeing x-rays of our teeth, MRIs of our brains and even the fuzzy images of fetuses in utero. These technologies have advanced far enough that now we are not surprised to see medical imaging systems installed inside Winnebagos parked alongside our local malls. Medical technologies have to image through tissue and bones. Imaging through two miles of ice is similar but requires different strategies. The Gamburtsev Mountain expedition is our best chance to image and to understand the ice sheet and the mountain range.

The Scale of the Problem
When mapmakers project our spherical world onto flat pieces of paper, the polar regions inevitably suffer. Usually the poles slide off the edges of the paper. Sometimes, Greenland is so warped that it appears as large as South America. Frequently, Antarctica is missing or sliced into triangular slivers or portrayed as a thin white border. Even Google Earth produces distorted shapes in the polar regions. Sparsely inhabited and situated at the mathematically challenging 90 degree south latitude, Antarctica is unfamiliar terrain. It is difficult to explain the scale of the problem of the Gamburtsev Mountains that sit in the continent that slips off the page.

The most familiar part of Antarctica, which usually remains on global maps, is the Antarctic Peninsula. This long, narrow string of mountains resembles a long arm reaching northward toward South America. Home to many penguin colonies and scientific bases, the peninsula is the prime tourist destination.

Less familiar is West Antarctica, the portion of the continent that rests in the Western Hemisphere.  Geologically, West Antarctica is a piece of thinned continental crust—like the Red Sea or the Gulf of Mexico. If this part of the continent were not covered with an ice sheet, it would be an open seaway rimmed with islands. A fragment of thick, cold continental crust, similar to eastern Canada, East Antarctica is bigger than the lower 48 states.

Scientific bases rim the margin, but only a few are in the interior, far from the logistical lifeline. South Pole, Vostok and Dome Concordia are the well-established stations in this part of the planet. The Chinese are working to build a station atop the Gamburtsev Mountains at Dome A, but nothing is in place yet. In the middle of East Antarctica, far from the permanent scientific bases and logistical hubs, the Gamburtsevs are completely hidden by the ice sheet. While these mountains rival the North American Rockies and Cascades, satellite imagery of East Antarctica is nothing but monotonous white space.

To study these hidden mountains, we will work from two camps. The southern camp is almost 800 miles (1,285 kilometers) from McMurdo, the main U.S. station, more than the distance between New York City and Chicago—only there are no highways, rest areas or gas stations along the way, just miles and miles of ice. Our northern camp is 470 miles (755 kilometers) inland and is closer to the Australian and Chinese bases on the northern edge of the ice sheet. Where we're working, there will be no penguins and no tourists, just ice, scientists, engineers, pilots, medics, cooks and mountaineers.

For several years, we have been puzzling over the logistics. How can a multinational team (of more than 25 scientists and engineers with three aircraft) cram an expedition into the very short time that the weather is warm enough for us to work? "Warm enough" means the temperature is warmer than –58 degrees F (–50 degrees C). After five years of planning, we have a strategy. 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. A surface traverse looks like five vehicles that have escaped from a construction site that are towing sleds filled with gear and fuel. The northern camp will be supplied by aircraft ferrying material from the coastal stations. Four air drops from U.S. Air Force jets will deliver fuel to the northern camp. The three science teams will prepare the aircraft in McMurdo through the month of November. After the systems are tested, the teams will move to the South Pole to acclimatize to the high altitude before beginning the move to the southern camp.

The program has already begun. The Australian team sailed from Hobart, Tasmania, in mid October. The British science team arrived in Antarctica last week to prepare the aircraft for the northern camp.  The team preparing the U.S. aircraft in Antarctica came on November 10. Now we will see if our strategy to image the Gamburtsev Mountains can put them back on the map.

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