02 May 2010

Retreating glaciers and melting ice yield treasures


A variety of reports are coming from various arctic regions indicating that retreating icefields are revealing rare artifacts that have been covered by snow and ice for thousands of years.  It's not a new phenomenon, but as more ice recedes (and more seekers search the tundra) much more is being found.
Ice patch archeology is a recent phenomenon that began in Yukon. In 1997, sheep hunters discovered a 4,300-year-old dart shaft in caribou dung that had become exposed as the ice receded. Scientists who investigated the site found layers of caribou dung buried between annual deposits of ice. They also discovered a repository of well-preserved artifacts.

Andrews first became aware of the importance of ice patches when word about the Yukon find started leaking out. "We began wondering if we had the same phenomenon here."

The results have been extraordinary. Andrews and his team have found 2400-year-old spear throwing tools, a 1000-year-old ground squirrel snare, and bows and arrows dating back 850 years. Biologists involved in the project are examining dung for plant remains, insect parts, pollen and caribou parasites.

"We realize that the ice patches are continuing to melt and we have an ethical obligation to collect these artifacts as they are exposed," says Andrews. If left on the ground, exposed artifacts would be trampled by caribou or dissolved by the acidic soils. "In a year or two the artifacts would be gone."
Pictured in the photo is a copper point hafted on to a bone or antler shaft, found in an Alaskan ice patch. (Source: Dixon, NPS).
In the picture above you can see a remarkable barbed bone projectile point with a copper tip, presumably made from a nugget of native copper. Two others with copper staining each date to about 1600 years ago, suggesting this is not copper traded from Europeans. Below, you can see the careful lashings of sinew that once held a projectile point to an arrow shaft.
Other researchers in Canada have found spears and atlatls:
An atlatl dart was the first artifact picked up at one of the sites. It was dated at about 4,300 years old, which made it one of the oldest artifacts of this kind ever found in North America. But that dart now seems almost modern compared to a second one that has since been found. It was dated at 6,800 years old...

At first people used spears, hurling them through the air with as much strength as they could muster. Then they figured out how to use atlatls, or throwing boards, to provide more leverage, basically extending the length of the throwing arm.

Bows and arrows evolved much later, showing up in the high arctic about 3-4,000 years ago. Beautifully preserved specimens have been dug out of the frozen ground there.
Additional photos of recovered specimens are posted at YourYukon.   What's remarkable of course is that much of this material is organic (wood, bone, sinew, feathers(!)), and would not have survived buried in soil or exposed to the elements.  But protected by ice these items have been sitting on the rocky ground for millennia waiting for someone to find them.

I've participated in conventional archaeological digs and have been excited to find shards of pottery and flakes from point-making.  I can't imagine the thrill that must occur to find specimens like these lying on the ground.  I'm jealous.

5 comments:

  1. So, thousands of years ago the climate was probably warmer.

    ReplyDelete
  2. gbradley - no. The artifacts were deposited on the ice in the first place, as people hunted caribou which were seeking shelter from insects. The fact that they have not melted out for up to 8,000 years suggests that the recent warming trend is unprecedented in that period of time.

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  3. Yes, consider this, gbradley. If it was warmer back then, as is your conclusion, then the near immediate and sustained frozen preservation of these organic artifacts would simply have been impossible.

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  4. @ Grahm
    http://motherjones.com/blue-marble/2009/11/ice-age-froze-europe-months
    It's not impossible.

    ReplyDelete
  5. gbradley, I don't see what about your link is relevant. The sudden cooling events have been well known for some time. The 8200 BP event was a sudden dip followed by return to normal. In other words, it was not a warmer period in the past. None of the ice patch materials relate to the Younger Dryas period or the climatic fluctuations of the end of the last ice age. You would be wanting to show evidence that the climate was in fact warmer at times during the Holocene sufficient for artifacts to be deposited in places where there is now melting ice. In fact, your own link shows the opposite.

    Anyway, I think the global warming angle on this story is a complete red herring and an unwelcome diversion from the cool archaeology which is disappearing before our eyes.

    ReplyDelete

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