While exposed wood usually rots and disappears, under the right conditions it can survive for millennia. Whereas regular glaciers consist of heavy sheets of ice that flow as much as tens of metres per year, snowdrifts that accumulate in a shady spot or depression can accumulate and turn into solid ice over the years that then stays put.
This increases the chances of finding intact artefacts, now that warmer conditions are melting these mini-glaciers.
They are keen to find out whether the method used to make it will indicate its age and what type of animal bone was used.
Bretten got interested in finding artefacts in snowdrifts in Oppdal when he was 17 and read an archaeological thesis about the topic.
Though still heavily used, relative dating is now augmented by several modern dating techniques.
When the ancestors of many of today’s Norwegians hunted reindeer in the mountains they would occasionally miss a target or damage their weapons – losing or discarding them in the snow.
Under the right conditions some of these artefacts have been preserved in ice for thousands of years. (Photo: Åge Hojem and Martin Callahan/NTNU University Museum)Just a few years ago archaeologists figured the oldest objects anyone could expect to find in snowdrift glaciers would be about 2,000 years old.
But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes.
Until this century, relative dating was the only technique for identifying the age of a truly ancient object.