The Commonwealth Glacier flows through a mountain pass down into Taylor Dry Valley.
The Dry Valleys
Dream
My dream of going to the Dry Valleys of Antarctica started when I was at MIT. The US Geological Survey published a book of selected images of Antarctica, I still have the book "USGS Proffesional Paper 591,Selected Aerial Photographs of Geologic Features in Areas Outside the United States".I was intrigued by these photographs and ordered two black and white prints for myself. The prints showed the Commonwealth and Canada glaciers flowing into the Dry Valleys. Two glaciers that flowed down through a narrow gap in the mountains then spread into nearly perfect semicircular arcs ending in 60 foot vertical cliffs. These became the glaciers of my dreams I began to work toward getting myself to the Dry Valleys to see, and feel these glaciers.
Reality
Thirty-five years later having become a scientist an author and a mountaineer, I was on a Huey helicopter flying to the Dry Valleys. I was flown across McMurdo Sound and into Taylor Dry Valley. The first glacier to appear out the right window was the Commonwealth glacier. It gleamed brilliant white against the brown rock slopes of the valley. I smiled from ear to ear, it was all that I expected it to be. A glacier that flowed downhill and vanished into thin air.
Mary Miller and I flew on to the camp at Lake Hoare located just under the cliffs of the Canada Glacier. Rae Spain the camp manager welcomed us to camp. She gave us tea and the Dry Valley lecture. The Dry Valleys are very special areas, we had to carry pee bottles with us on our hikes. I could see that "carry in, carry out" took on a whole new meaning in these pristine valleys. We were even discouraged from leaving footprints, hikers are asked to follow previous footprints wherever possible.
After our greeting, glaciologist Andrew Fountain explained the origin of the cliffs. The story had two parts: the temperature of the ice and the dry winds. These were cold glaciers, the ice from top to bottom was -17 C. Unlike temperate glaciers which slide on a layer of water these polar glaciers were frozen to the ground, they didn't slide along they rolled forward like caterpillar tractor treads. This caused the top of the glacier to jut forward and overhang the bottom. Ice is not good under tension so the jutting cliffs would avalanche down into a pile of debris. Then the wind played its role. Cold air from the polar plateau falls down into the dry valleys, pulled down by gravity. These winds, known as katabatic winds, are compressed as they drop to the bottom of the valley becoming warmer and drier. The high speed winds cause the avalanche debris to sublime away. Thus these glacier do vanish into the air, one of natures best magic tricks.
A second glaciologist Thomas Nylen invited me to go for an exploration of the Canada Glacier. I was excited to learn that my exploration would require me to use an ice axe and wear crampons: I was going to climb the Canada Glacier. We were accompanied by
volunteer Virginia Butler, who was an archeology professor on sabbatical, and Masters degree student Sarah Tegt. Our first stop was to install a bamboo pole in the ice, we all took turns boring the 2m deep hole. Virginia pronounced me "hoss" for the "hosspower" I provided to the drilling project.
We drilled our hole next to another bamboo pole which was sticking nearly 2 m out of the ice. The poles are used to measure the ablation of the glacier. Twice a year Thomas measures how much ice has disappeared by measuring how far the pole sticks up from the ice surface. The old pole had melted almost completely out of the ice in 8 years.
After installing the pole we hiked along the glacier. I saw some neat circular holes ranging in size from a silver dollar up to a children's wading pool. I asked Thomas about these and he said they were cryoconite holes. Dirt blew on to the glacier and absorbed sunlight. The sun went around the sky in a circle and so made the hole circular. Each year more dirt was trapped by the hole so it grew larger and larger. The holes sometimes grew together making chains of holes. Every hole had a population of rotifers and tardigrades. Most years an ice lid remained over the hole sealing off its population from the air, but on a warm year like 2002 the ice lids melted and populations from different holes were picked up and dropped off by the wind. It was an amazing ecological story behind the simple appearance of circular holes in the ice.
This was an amazing year. Andrew noted that he had been in the dry valleys since 1993. He had seen grooves that had been cut into the top edge of the glacier and had known that they were supposed to have been carved by running water, but he had never seen water flow off the glacier. This year however, large waterfalls poured out of every glacial channel.
It seemed strange to be able to walk on a glacier unroped. But these dry valley glaciers do not have crevasses. Cracks in the glacier open so slowly that they quickly fill with water and freeze solid. This also means that streams meander across the surface of the Dry Valley glaciers, unlike temperate glaciers which capture streams in crevasses. These streams flow all the way to the cliff at the end of the glacier where they pour off as a waterfall. The waterfalls feed the glacial lakes like Lake Hoare. This year Lake Hoare was surrounded by a wide water moat that stopped researchers from taking the 15 minute walk across the lake. We all had to take the 2 hour walk around the lake instead.
Andrew's Ridge
On another day I went for a solo hike around Lake Hoare and along Andrews Ridge.
The moat discouraged any thoughts I might have of walking across the lake. As I hiked around the lake I heard the ice crumbling into the water beneath the bright Antarctic sun. I also caught the flash of wings flitting over the lake ice. "What birds are those?" I thought. When I looked closer they weren't birds at all, they were thin plates of ice tumbling in the wind along the ice and flashing in the sun. Human eyes are really tuned to spot life.
As I walked I noted a strange rock ahead. It turned out to be a mummified seal. I had heard that some of these seals had been radiocarbon dated and found to be thousands of years old. They had crawled over ten miles from the ocean, died, and been freeze dried. The wind blown snow and grit sandblasted the fur from the mummies. After a long time the flesh was removed exposing the bones. After reading about these seal mummies as old as the Egyptian pharaoh mummies I was stunned to see a fairly fresh dead seal, Thomas told me it had died in the last year. It was as shocking as encountering a freshly dead pharaoh.
Seal sandblasted down to the skeleton.
Dead seal in the outflow stream of the Canada Glacier.
After this parade of death I was startled to see a shadow move across the ground. I looked around and saw it was a skua checking me out.
There is a way to cross the river that flows from Lake Chad to Lake Hoare by jumping from stone to stone. On the lake Chad shore I spotted a strange brownish lump about the size of a cow patty. When I later asked Biologist John Priscu about my photo of the lump he identified it as cyanobacteria. It produces brown pigment as protection against ultraviolet, it also produces antifreeze proteins, and a neurotoxin.
This very simple life form made me think of the origins of life on earth. It might be simple but it was a powerful chemical factory. It was living and reproducing in one of the harshest climates on earth. When Robert Scott and his men camped by this lake and drank the water, the neurotoxin of this cyanobacteria gave them diarrhea. They used lots of toilet paper with the brand name "Chad." Thus the lake was christened.
I continued my hike up the end of Andrews Ridge. The ridge ran down the middle of Taylor Valley, it reminded me of images of Martian chasms which sometimes have ridges running down their length. As I hiked up the ridge the wind picked up. I noted that the stones underfoot became polished and faceted. I was walking among a sea of ventifacts, wind shaped rocks. The wind itself doesn't shape the rocks, but windblown grit and cold snow does. Cold snow, below -40 C, is harder than rock. The fine grained basalt rock weathered from black dikes that ran across the ridge took on a glassy finish when polished by the wind.
Some of the bedrock was shattered, perhaps by freeze/thaw perhaps by thermal cycling.
At the summit of Andrews Ridge I saw a large split granite boulder, pockets of cavernous weathering not only gave the boulder a fantastic shape, they also provided good handholds. I soon finished my first Dry Valley boulder problem, in the New Zealand rating scale the route I did was VE, or easy, but the approach from San Francisco is truly extremely difficult.
The pits near the summit of the boulder had two small circular disks of lichen growing in them, John Priscu said that rocks a thousand feet higher had more lichen because the moisture level was greater high above the Dry Valleys.
I stood on the boulder, and looked around at a world of shattered rock. It reminded me a bit of the views of Mars sent back by the Pathfinder robot. This was a lonely spot. I stood two miles from the nearest human, and felt like I was on another planet.
Eventually I chose to return from the world of stone and mummies, bacteria and lichen to the world of humanity. I made my way back to the wonderful people at Lake Hoare hut, for home cooked dinner, word games, partying, and a warm sleeping bag, in a tent, at the bottom of a Dry Valley.
Postscript
We were trapped for an extra day in the Dry Valleys by a rare snowstorm. No one complained about having to stay an extra day. I used my time well, I climbed the boulder in front of the Lake Hoare hut.
Dreams can come true.
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Scientific Explorations with Paul Doherty |
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15 January 2002 |