6,000 years of arrows emerge from melting Norwegian ice patch - National Geographic

Expeditions to survey the Langfonne ice patch in 2014 and 2016, both particularly warm summers, also revealed copious reindeer bones and antlers, suggesting that hunters used the ice patch over the course of millennia.

Since archaeologists started systematically surveying melting ice sites 15 years ago, ice patches from Norway to North America have yielded almost perfectly-preserved artifacts from long-ago time periods.

Langfonne, in fact, was one of the first ice patch sites to come to light, after a local hiker discovered a 3,300-year-old leather shoe sitting next to the edge of the ice patch in the summer of 2006 and reported it to archaeologist Lars Pilø, now a researcher at the Innlandet County Council Cultural Heritage Department and a co-author of the new study.

and the Alps in Europe—have wondered if the distribution of objects on and around the ice might tell them about how and when the ice patch sites were used and how they grew over time.

Sites like Langfonne, researchers assumed, resemble a patch of snow at the end of winter: As temperatures increase, artifacts trapped inside melt out in the order they were deposited.

That meant the oldest items would be found in the deepest core of the ice patch, in the same way that archaeologists working with artifacts buried in soil assume lower layers of dirt contain older artifacts.

The Langfonne arrows seemed like a way to test the time-machine theory.

Co-author Atle Nesje, a glaciologist at the University of Bergen, says that thousands of years ago, warm summers probably exposed older artifacts, which were carried to the edge of the ice patch by streams of meltwater before freezing again.

That meant using radiocarbon dated arrows to map the size of the ice patch in the past was a dead end.

“Glaciologists and ice patch archaeologists were hoping that artifacts could give us an idea of the size over time, but that’s not the case,” Reckin says.

Researchers were pleasantly surprised that the Langfonne arrows, once dated, could provide useful clues to how people used the ice patch over time.

Based on lichen growth on the rocks around the ice patch, Nesje estimates that Langfonne today is half the size it was in the late 1990s—and a tenth of its extent during the Little Ice Age, a centuries-long dip in global temperatures that lasted from about 1300 AD into the 1800s