“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.