The Norwegian glaciers in Oppland County have acted like a deep freezer for thousands of years, collecting artifacts from all the different cultures who lived among them. Now, faced with milder winters and earlier springs, the glaciers are receding and starting to pump out a tide of well-preserved ancient artifacts.

An international research team from Oppland County Council and the universities of Oslo, Trondheim, Bergen, Oxford, and Cambridge have recently joined forces to fully study the area. Their research into this was published today in Royal Society Open Science.

So far, they have managed to find over 2,000 artifacts, some as old as 6,000 years old, included Iron Age and Bronze Age clothing, sleds, arrows, ancient horse skulls, an 8th-century ski, and an 11th-century walking stick complete with a runic inscription.

"These kinds of short runic inscription from the Early Medieval Period are notoriously enigmatic, this one even more so, as it has had the upper and lower part of the letters shaved off after the inscription was cut into the walking stick," Lars Pilø, co-director of the Glacier Archaeology Program at Oppland County Council, told IFLScience. "However, runic experts believe that the most likely interpretation is "thanàivor" which translates from Old Norse as "This is owned by Ivar/Ivor."

By radiocarbon dating their discoveries, the team is even able to trace past patterns of human activity and climate change, like peeling through the layers of time. They found that the patterns of artifacts in the ice are determined by four things: the size of the reindeer population, the level of high altitude human activity, preservation issues, and climate history.

For example, there’s a notably decreasing number of objects from the 14th century CE, the time of the Black Death. Along with wiping out huge numbers of Scandinavians, the pandemic also disturbed trade from the rest of Europe, meaning that fewer goods were making it to the northern mountains. Equally, this was the start of the “Little Ice Age,” when the mountains were especially inhospitable.

“We [also] see particularly high numbers of finds dating to the 8th – 10th centuries CE, probably reflecting increased population, mobility (including the use of mountain passes) and trade – just before and during the Viking Age when outward expansion was also characteristic of Scandinavia,” Dr James H. Barrett, an environmental archaeologist at the University of Cambridge, said in a statement.

“One driver of this increase may have been the expanding ecological frontier of the towns that were emerging around Europe at this time," he added. "Town-dwellers needed mountain products such as antlers for artifact manufacture and probably also furs. Other drivers were the changing needs and aspirations of the mountain hunters themselves."

You can follow the ongoing research in Oppland through the Secrets of the Ice blog.