By Josh Landis, Antarctic Sun staff
You're looking at a sea of ice," said geologist Ron Sletten, sweeping his arm toward an expanse of brown, jumbled rocks. It looked more like the surface of Mars or a lifeless desert than any ocean on Earth. But the dry and barren landscape of Beacon Valley concealed a sleeping giant, one Sletten and his team have come here to explore.
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Beacon Valley is one of Antarctica's Dry Valleys. This area, which is about 4,800 square kilometers of almost completely ice free land between the Ross Sea and the Transantarctic Mountains, is the continent's largest year-round, ice free area.
Stretched out under tens of thousands of years' worth of deposited rocks and soil is a body of ice that may be a glacier nearly 10 kilometers (6 miles) long and hundreds of meters deep.
It would be completely hidden except for some tell-tale signs: Massive polygons that dominate the appearance of the surface. From the air, the pattern looks like dried, cracked mud.
On the ground, however, the cracks are mini-valleys between uplifted sections of earth 10 to 30 meters ( 30 to 100 feet) wide. Up to three meters (10 feet) deep, they hold some of the secrets to how the valley formed, and could provide information on the mysterious underground ice.
That ice, in turn, could help scientists understand how water could exist on other planets, particularly Mars. Sletten, who's here working on a research project conducted by a University of Washington scientific team, is a soil expert with vast experience in the Arctic. His lilting accent belies his Canadian and Norwegian roots, and he is as comfortable philosophizing over politics or travel as he is geology.
Here his focus becomes, in a way, geometric. The polygons in the valley are defined by cracks that can be several meters wide. When the underground glacier cools, the cracks between the polygons open slightly and sand falls into the gaps. When the polygons later warm they try to close the space, however, they cannot squeeze all the way shut again. As a result, the pressurized ice mixes with the sand and a zone of ice-cemented soil forms.
It's this ratchet-like action that causes these "cracks" to grow and deform the surface over time. Nobody knows exactly how long this mechanism has been taking place, or how old the glacier is.
One study dated it at 8 million years old, based upon volcanic ash found on top of it. That would make it by far the oldest ice on Earth. But that theory is under close scrutiny; there is no sound model that can explain how ice could survive that long. Sletten is among the skeptics, but he remains open-minded to the scientific claim and says he would love to be able to prove the age.
The biggest source of his disbelief is the fact that the glacier isn't covered by very much soil - a meter or less in some places. With that little coverage, the ice should have been sublimed by air in fewer than 8 million years. "It's hard to believe it lasted so long because it's so close to the surface," Sletten said. "But I'm not going to say bah humbug, either."
His team, which includes researchers Dan Mann and Margaret Smith, is canvassing the valley, trying to divine the history, age and personality of the ancient ice. They're using GPS units to track movements of the glacier, gravity meters to determine its depth, and have placed several monitoring instruments deep into the ice to measure temperature, humidity, movement and other variables.
The team is also taking samples of the glacier at certain locations, but keeping activity to a minimum to avoid impacting the pristine landscape. All holes that are dug get filled in again, and the researchers take care not to disturb too many stones while walking. Sletten uses an alcohol-lubricated chain saw to extract small samples, which he will take back to the States and examine.
The biggest questions are how old the ice is, and how it came to be where it is. "We're trying to find out if there's a record, and if it's readable, said Mann. "If you had 8 million year-old ice, it would provide information about a period of the Earth's existence that there's no data on," he said.
It could extend the length of environmental records frozen in ice by nearly 20-fold. Currently, the oldest glacial ice is estimated to be 450,000 years old but is much less accessible than Beacon Valley; it is more than two miles beneath the East Antarctic ice sheet over Lake Vostok.
The setting of Beacon Valley may seem otherworldly at times, and the findings of the research there could have truly far-out implications. Polygons that look similar to the ones in the Dry Valleys have been sighted on Mars. If scientists are able to judge ice forms and movement under the surface here, they could apply that knowledge to the red planet. A research associate of Sletten's has already written papers on Martian polygons, and there are two planetary scientists that will assist with the finding of the research in Antarctica.
With its rugged, reddish-brown complexion, it wouldn't take a great stretch of the imagination to place Beacon Valley on Mars.
"Try to step where I step," Sletten said as he made his way across an intricate mosaic of flat, wind-polished stones that stretched in all directions. "This surface would take a long time to heal if it gets disturbed."
The natural, interlocking phenomenon is called "desert pavement," and it's very pronounced in parts of Beacon Valley. "This surface is probably tens of thousands of years old," Sletten said. "It's like artwork." Footsteps leave tiny sand divots in the ground, exposing the fine soil underneath to the relentless winds above. A trail made several years ago was still plainly visible, showing no signs of going away anytime soon.
When it comes to the ground, Sletten is an enlightened man. He knows soil is more than irrelevant matter we build on top of, or walk over. It is a dynamic relationship between rocks and sand and other particles, wind and water. The ground changes, it evolves, and if we look closely enough, it tells us a detailed story about the past.
If anywhere, Beacon Valley is a place where ancient secrets lie undisturbed. Published Jan. 7, 2001 in USA Today