October 24, 2014

Warming world uncovers frozen past

by Bonnie Denmark

What’s that smell? If you are on an ice patch in the Yukon Territory in Canada, the answer might be millennia-old caribou dung.

Weapon shaft in Yukon ice patch (Credit: Yukon Government)

In 1997, sheep hunters came upon a vast field of caribou dung in a place where the animals had not been seen in 70 years. The dung had surfaced from a melting ice patch, and at the edge of the patch a small stick was found with sinew and feather still attached. Radiocarbon dating showed that the stick was 4,300 years old. This accidental discovery marked the beginning of the Yukon Ice Patch Project, which catapulted the region to worldwide prominence in the emerging field of glacial archaeology.

Jotunheimen mountains, Norway (Credit: Wikimedia Commons)

Since that first fortuitous find, thousands of others followed. The oldest artifact from the region is part of a hunting dart, dated at more than 9,000 years old, almost back to the end of the Ice Age. But ice patch archaeology is not limited to the Yukon. Norway is another major center for glacial archaeology, and there are active projects in the US, Switzerland, Italy, Austria, Peru, Siberia, Ukraine, Kazakhstan, Greenland, the South American Andes, and other regions as well. The discipline has garnered so much interest that it holds international symposia and has its own journal, the Journal of Glacial Archaeology, set to launch in November 2014.

The boom is attributed to rising temperatures across the globe. Ice patches were formed over thousands of years as annual snowfall was compressed into layers. Unlike glaciers, which move and crush objects, ice patches are uniquely suited to preserve objects that are frozen under a new layer – and each layer tells a story of its time. “We came to realize that in the face of global warming, alpine areas around the world were revealing extraordinary and unprecedented objects that had been frozen in ice for thousands of years,” said Greg Hare, a Yukon government archaeologist and leader in the specialty (TED: The Leading Edge, 2013).

Warming temperatures over the past two decades have caused treasures to ooze from the thaw faster than archaeologists can recover them.  Precious objects kept on ice for thousands of years remain remarkably intact, but when they come into contact with acidic soil, air, and rain, they can decompose rapidly. As alpine ice patches recede and disappear, archaeologists feel a sense of urgency as well as an ethical obligation to recover cultural resources at risk of being lost forever.

Retrieved from Yukon ice patch (Credit: Yukon Government)

Finds from the worldwide melt-out include

  • hunting artifacts, walking sticks, and tools
  • hundreds of Viking objects
  • a Viking horse skull
  • animals bones
  • an early ski
  • a Roman brooch
  • textiles
  • leather clothes, shoes, quivers, and pouches
  • mummified small mammals and birds
  • woolly mammoths
  • burial mounds
  • human remains

Reconstruction of Ötzi the Stone Age Iceman (Credit: Thilo Parg / Wikimedia Commons)

Some human remains were so well preserved that their last meals could be determined. One of the first such discoveries was the frozen body of Ötzi, a Stone Age mummy found in the Italian Alps in 1991. Well preserved bodies of ancient Incans, likely human sacrifices, have been recovered from the mountains of South America. And in 1999, in northern Canada the remains of a young man were discovered from before the time when Europeans arrived. He was called Kwaday Dan Ts’inchi in the local language, which translates to “long-ago person found.” DNA testing revealed 17 living relatives.

These finds have spawned research in many areas: Pollen and insects trapped in the dung provide a glimpse into ancient plant and animal life. Scientists look at DNA, investigate changes in the environment over the millennia, and surmise the diet, habitat, and genetics of long-ago populations. In addition, archaeological finds give us a clue to past climate change. In the Swiss Alps, for example, 1,000-year gaps in the ages of artifacts point to periods when glacial ice prevented passage over the mountains, and the preservation of organic materials for 5,000-plus years indicates that the ice cover has not been this small since the end of the Stone Age (Curry, 2009).

Carcross-Tagish First Nation Field assistant Tagish Johns recovers artifact from Yukon ice patch (Credit: Stephen Krasemann)

The heritage aspect of these archeological finds must be highlighted. In the Yukon Ice Patch project, First Nations members participate in the discovery of objects from their cultural past. According to Hare, “It’s at the community level that these exquisitely preserved organic objects have had the greatest impact. They ignite the imagination not only of people looking at them and the people who study them but especially of the people who are looking for them.” (TED: The Leading Edge, 2013)

And to think it all started, in the Yukon at least, with caribou dung.

 

FOR MORE INFORMATION

Read about archaeological sites worldwide put at risk though climate change in Andrew Curry’s Climate Change: Sites in Peril. Archaeology, 62(2), March/April 2009.

Learn more about the Yukon Ice Patch project by viewing The Leading Edge – Yukon’s place in the developing world of glacial archaeology: Greg Hare at TEDxWhitehorse, 2013.

To read more about the First Nations collaborative projects underway in the Yukon, check out the Ice Patch Newsletter, 2005.

Learn more about radiocarbon dating in our module Uncertainty, Error, and Confidence.

 

Written by

Bonnie Denmark holds an MA in linguistics and teacher certification in English, ESL, and Spanish. She has devoted her professional life to educational and accessibility issues as a computational linguist, multimedia curriculum developer, educator, and writer. She has also worked nationally and internationally as a language instructor, educational technology consultant, and teacher trainer. Bonnie joined the Visionlearning team as a literacy specialist in 2011, assisting the project by developing comprehension aids for science modules and creating other STEM learning materials.

The views expressed above do not necessarily represent those of Visionlearning or our funding agencies.