In 1903, explorer Robert F. Scott and his team stumbled on an anomaly in the frozen, white expanse that is Antarctica: the Dry Valleys, fields of exposed rock with virtually no visible ice. Since 1986, geologist David Marchant of Boston University has spent nearly every Antarctic summer here, decoding a unique landscape. Journalist Jennifer Berglund, assisting Marchant in the field, kept a diary of her adventure.
Tuesday, Nov. 13, 2012 | McMurdo Station to Upper Friedmann Valley
This morning, four of us hopped on a helicopter at McMurdo Station, the United States Antarctic Program’s base, near the spot where Scott’s men built a hut in 1902 to wait out the long winter. Along with my fellow field assistant Keith Heyward, I was joining Marchant and his graduate student, Sean Mackay, flying 60 miles across the sea ice to the Dry Valleys, a series of valleys and ridges that lie roughly east to west and largely free of the ice that covers 98 percent of the continent.
Most glaciers are wet-based: A layer of water beneath the ice makes the glacier mobile, capable of creating steep fjords and other dramatic features that we associate with glacially sculpted terrain. The Dry Valley glaciers are cold-based: Too frigid to melt, their geological footprint is more subtle.
Marchant, with support from the National Science Foundation, is a veteran of Dry Valley expeditions, and this is Mackay’s fourth season. As a rookie, I have no idea what to expect. I’ve done my share of adventuring, but this is a whole new level. I’m wondering if I’m really up for this. For six weeks, I will be without a shower, peeing in a bottle and sleeping in a tent in the coldest, driest place in the world.
From the helicopter, the land below resembled a massive explosion of white cake frosting over mountainous terrain. It was covered with glacial ice — the East Antarctic Ice Sheet. It is the largest in the world. In parts, it’s nearly three miles thick, and, with the nearby West Antarctic Ice Sheet, it blankets an expanse roughly the size of the United States and Mexico combined. If both ice sheets melted — a process already underway at an alarming rate in West Antarctica — global sea levels would rise 200 feet.
We flew over a break in the mountains, and the ice ended abruptly, revealing a flat valley. It looked like a dry, rocky riverbed. Mackay nudged me and pointed down. “That’s Beacon Valley,” he yelled, “our next campsite.” For now, we continued farther south to a smaller inlet called Friedmann Valley.
When we reached our campsite, we unloaded our gear. The helicopter took off in a maelstrom of blowing sand and rock, leaving us in the middle of a giant boulder field stretching several miles north toward Beacon.
It’s now evening, and we’re surrounded by craggy walls banded with ruddy bedrock and tawny sandstone. Farther north, buttes and mesas resembling the American Southwest flank a flat valley floor. Beyond Beacon, the shelf of Taylor Glacier shows hints of baby blue. The cliffs surrounding us are glowing red. During the austral summer — October through February — the sun never sets here, but it does fall closer to the horizon, which spreads a narrow spectrum of warm light across the landscape, drawing out vivid, contrasting hues.
Wednesday, Nov. 14, 2012 | Upper Friedmann Valley
We woke up this morning to a different Antarctica. This was more like the one I’d read about — blustery and frigid at zero degrees Fahrenheit. The wind rumbled through the mountain peaks like distant thunder. Seconds later, it struck — a furious explosion that threatened to blow down our only shelter. But I was relying on a Scott Tent, designed by its famous namesake more than a hundred years ago and little changed since, a testament to its ability to withstand hurricane-force winds not uncommon on the continent. Scott Tents are large, tepee-like structures, with an array of guy lines that can be fastened to boulders or metal anchors buried and secured in the snow.
Because there were such strong winds today, it wasn’t optimal for digging pits. That meant Mackay couldn’t do his fieldwork, so he offered to take us on a walk while Marchant spent some time reading the landscape in solitude. Over his many seasons here, Marchant has found he does his best work alone. The veteran Dry Valleys expeditioner is a master, Mackay says, of pulling tiny pieces of evidence together to tell a much grander story.
Mackay, a tall, fit, 37-year-old climber, moved effortlessly across the rugged terrain while Heyward and I struggled. Covering the ground as far as the eye could see were large rocks and boulders, constantly tripping me in my cumbersome standard-issue “bunny boots” — white, clownlike shoes with a sole about an inch thick and little valves on the side to restrict the outflow of warm air.
We walked 50 feet down a steep slope to a flat area. Mackay explained that we had just been on top of relatively young glacial ice buried beneath the rubble. The slope was the edge of the glacier, but now we were walking on solid ground. We continued north toward Beacon while Mackay explained that the farther we got, the older the buried ice became.
The terrain beneath our boots was a time capsule. Roughly 14 million years ago during the Middle Miocene Climate Transition, ice stopped melting in Antarctica’s southern Dry Valleys. Temperatures plummeted to about 14 degrees Fahrenheit, never again to rise above freezing at high elevations. The air dehydrated, leaving a frozen landscape with less humidity than the Sahara. From that time forward, the landscape has remained largely unaltered.
Once we reached Beacon Valley, Mackay scoured the ground and knelt down. Using his hands, he dug through the rock and sand, and hit something solid. Hammering at it with a rock, it chipped — ice! He gave Heyward and me a couple of pieces to suck on. Mackay estimated the ice could have been as old as 800,000 years, making it roughly the same age as the oldest ice ever core-sampled from anywhere in the world.
Marchant and colleagues have found that pockets of slow-moving buried glacier ice can persist for millions of years — 8 million years for ice found in central Beacon. Some ice in the valley could be even older. Not long ago, it was thought impossible for ice to remain intact for millions of years: Scientists assumed it would eventually sublimate, transforming in the frigid, dry air directly from ice to vapor. But new modeling studies by Marchant and his team have shown that sublimation of deeply buried ice is extremely slow, less than a tenth of a millimeter per year. Under certain conditions, the buried ice can persist almost indefinitely.
Friday, Nov. 23, 2012 | Camp move to Central Beacon Valley
We moved our camp north today to Central Beacon Valley. It was an all-day affair of packing, unpacking, organizing, loading and unloading the helicopter. The landscape here is different from what I imagined it would be. The boulders are much smaller than the ones in Friedmann, and the terrain is easier to navigate. In parts, the rocks fit together like a Roman road in a multicolored mosaic of rock types: sandstone, volcanic dolerite and granite. Judging from the rocks’ small size and smooth texture, Marchant told me it would have taken the snow and wind millions of years to whittle them down. They must have remained in the same position for thousands more to fit together like puzzle pieces.
Saturday, Nov. 24, 2012 | Central Beacon Valley
We had our first real snow today! I’ve never seen anything quite like it. The flakes were massive. They looked and sounded like little balls of Styrofoam as they fell. Marchant said they would accumulate for only a short while before being either blown away by the wind or sublimating. Low clouds covered most of the landscape, but occasionally they cleared just enough to reveal a lacy layer of snow covering the mountainsides.
Heyward and I spent most of the day in the cook tent readying equipment for the field. Despite being out of the wind, a day like this, with little strenuous activity, is just about the worst thing when you’re trying to stay warm. Without much movement, the cold hits your fingers and toes first, making your bones ache and shooting pain all the way up your extremities. Several times, I had to run out of the tent and up a nearby hill to get my blood pumping. I hope tomorrow is more active.
Friday, Dec. 7, 2012 | Camp move to Upper Beacon Valley
Another camp move today. We’re now just a few miles south of Central Beacon. It’s our final campsite, which is bittersweet. Aside from the cold, life out here is simple: eat, sleep, work hard, chat. There is a kind of camaraderie that grows from working in the field, particularly within a small group of four. One more week, and I’ll be heading back to a bustling city. I think I’m more worried about assimilating back into normal society than I was about living outside in the middle of Antarctica.
Monday, Dec. 10, 2012 | Upper Beacon Valley
We are camped at the point where Friedmann and Mullins Valley meet Beacon. The ice here is younger and cleaner than ice farther north in Central Beacon, so it’s a good place to drill for an ice core sample. The bubbles of atmospheric gas trapped inside a sample can be analyzed to reveal information about past conditions and, by extension, past temperatures. Marchant estimates the ice here could be 4 million years old, five times older than the oldest cores taken from elsewhere. If we manage to drill a good sample, it would help place ongoing climate change within a long-term geological framework and provide compelling evidence for past changes in the atmosphere and global ice volume. Access to that information would enable scientists to predict future change more precisely.
“In the next 50 to 100 years, we’re going to see carbon dioxide levels in a realm that we have never observed in the records we have, which really only date back 800,000 to 1 million years,” Mackay told me. “We’ve just never seen levels that high.”
Scientists believe there are earlier periods in Earth’s history with comparably high levels of the gas. The trouble is, ice cores are the gold standard for estimating past atmospheric carbon dioxide levels, and Marchant says the Dry Valley glaciers are the only ones known to contain ice that old.
Although samples from previous seasons have been useful for other research, Marchant has yet to obtain a core with a pristine carbon dioxide record. Drilling a good core — while not impossible — is challenging and takes time. Drills designed to cut through rock use warm water to rinse the blades during the process, which can destroy an ice core. For the best chance of an intact sample, researchers must hunt for areas of solid ice that can be cored with drills used specifically for that purpose. Even when a prime, rock-free site is found, samples can be contaminated with microbial activity or by modern air that seeps in when temperature changes cause the ice to crack.
Thursday, Dec. 13, 2012 | Upper Beacon Valley
I woke up to a surprisingly hot day in Upper Beacon Valley. It was about 30 degrees, and I was burning up. I made a sweaty exit from my sleeping bag and stripped down a few layers to my long underwear. It still seemed hot.
Today we had to excavate an ice core from a patch of buried ice we uncovered yesterday. For once, I wished for cold.
Exposed ice glistened as it melted from the surrounding dark rocks heating in the sunshine. Mackay and Heyward took turns twisting the manual, cylindrical drill into ice and rock. It’s a low-tech version of the drills they usually use, and it is typically employed to test core quality at a site before large-scale drilling. Mackay pulled it up. Fractured pieces of ice fell out of it. It was certainly not the solid piece we needed. We sighed in disappointment. It wasn’t good enough for science, but Mackay had something else in mind. He bagged it, and we took it back to camp.
That night, bad weather came in again, but this time without wind. It was snowing; a thick cloud covered the mountaintops and much of the landscape. It was much colder now. We huddled in our cook tent and listened to some music on a pair of battery-powered speakers while Mackay made us a treat: a dash of rum with Raro, a Tang-like powder drink popular in New Zealand, the last civilized port of call for researchers heading to the Dry Valleys. Mixing in the crumbled bits of ancient ice, Mackay poured us all a glass, and we toasted the adventure.
Fog surrounded our campsite. We could have been on a mountaintop, a freezer, a studio — it was impossible to tell. You could see nothing but a fuzzy white wall a football field away in every direction. Mackay’s kite, which, for fun, he had tethered to the tent, was high above us — a black speck, with the long, dotted line of a tail hovering in a white void.
