December 1, 2008 | 2
Editor’s note: Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet. Following is the fifth of her updates on the effort as part of ScientificAmerican.com‘s in-depth report on the "Future of the Poles."
McMURDO STATION, ANTARCTICA — In the U.S. Thanksgiving, with the traditional turkey dinner, is held on a Thursday. Here in Antarctica, the festive meal for the 1000 residents of McMurdo is served the Saturday after Thanksgiving. The Saturday holiday provides a rare two-day weekend for a community that works at a grueling pace. This Thanksgiving Saturday brings a howling blizzard up the McMurdo Sound. The ‘Turkey Trot’ out onto the sea ice is postponed because of the increasing winds and decreasing visibility. Even our Canadian gravity engineers have been driven away from the survey aircraft. While they were eager to move forward, it seemed imprudent to stay in the canvas-sided building wobbling in the wind. The 50-knot wind is buffeting the sides of the Crary Lab and the normally spectacular view of the Royal Society Mountain Range is gone. The Crary Lab is a modern science building that could be on any university campus except that the front doors look like a walk-in freezer. The blizzard has all the scientists holed up in the Crary Lab.
The wind provides the AGAP team of airborne geoscientists a chance to talk with the team from the U.S. Norway Traverse. This team will drive a series of four track vehicles across the continent from the U.S. base at the South Pole to the Norwegian Troll station, collecting shallow ice cores and making geophysical measurements. After our discovery of four subglacial lakes two years ago, the traverse team diverted its route to drive right down the middle of all the lake. Since we are planning to fly over the lakes in the aircraft a few days before they arrive, we want to coordinate our efforts. After days of worrying about fuel, sleeping bags, altitude sickness and logistics, it is wonderful to talk about science. I have to take a deep breath and close my eyes to shift gears and move my head back to thinking about what is hidden beneath the ice.
These four lakes, together the size of New Jersey, are buried beneath more than a mile of ice. I had spent an entire winter obsessed with these features. No scientist has visited this area since the time that I was in first grade (1964), but much of that data is still valuable. It is the only data in the region. Working together, we have the opportunity to understand why these lakes are here. Maybe there is major tectonic fault or possibly a region of high geothermal heat flow beneath the ice sheet. We are working to coordinate our experiments to optimize the results. The gravity measurements from the ground or the air will enable us to estimate how deep the water is in the lakes. The airborne magnetics will let us test the idea that there might be volcanics in this region. Perhaps we can use the layers in the ice sheet to determine if these lakes have drained in the past. We have three ways to image them: from our aircraft, from the measurements towed along with the traverse vehicles, and with the Cryowing, an unmanned aerial vehicle.
Each method will tell us something different about the lake, but we have limited time so we have to optimize everything. We debate whether the most important question is why the lakes are there or if the lakes are changing. Our decision will determine the exact lines we fly and where they drive.
After two hours, we agree to meet later this week to finalize the plans. We will start our projects from the South Pole in about 10 days, but now Thanksgiving dinner calls. We head off to put on fresh shirts and enjoy, at last, our chance for turkey and pumpkin pie miles from home.
(Photo courtesy of Robin Bell showing the US and BAS helicopters at Willy Field, the US Antarctic Program’s main airfield at McMurdo, during the 40 mph plus winds on Thanksgiving Day.)