Sifting through garbage from the end of the Ice Age

This summer, archaeologists are continuing work at a 12,000-year-old prehistoric site which is yielding evidence of generations of wandering hunters who camped on a bluff overlooking the Kivalina River. What they have found is contributing new insights—and contrary new evidence--into the thinking on how humans spread throughout North America at the close of the Pleistocene. 

Aerial view of Raven Bluff and the Kivalina River [Credit: Bureau of Land Management/photo by Craig McCaa]
The Raven Bluff site was discovered in 2007 by BLM archaeologist Bill Hedman and a crew conducting an archaeological site survey in the far northwest corner of Alaska. The Bering Land Bridge between Russia and North America may have still existed--or had just submerged for the last time--when hunters first frequented Raven Bluff. 

No summer blockbusters here: “Remote,” is how chief archaeologist Jeff Rasic , a curator for the University of Alaska Museum, describes the site, accessible only by helicopter. 

“You can’t run back to town for another battery. If there’s a medical problem you are days or a week away from help. It may be raining buckets, in slightly above freezing temperatures, and you’re digging in the dirt doing meticulous, precise scientific excavations. You get used to a certain level of filth, and then you go take a dip in the ice-cold river, then as soon as you get out you’re a mosquito meal. That’s just part of the deal working in the Arctic.” 

Essentially the remains of a garbage dump, the dig has offered up the oldest preserved animal bone site in the American Arctic. “We rarely find animal bones because they rot away so fast,” notes Rasic. Rapid soil accumulation, low soil acidity, and perennially frozen conditions at Raven Bluff resulted in bone preservation that is not seen at any other Arctic site of this age. 

“The people that came here would be astounded by the time, energy and thought we’re spending exploring garbage they wouldn’t have given a thought to. But it’s telling us what people were eating, what seasons they were at the site, how they were processing animals, how they carried, preserved and stored food.” 

For example, the notion that people at this time period were bison hunters in Northern Alaska is being put to the test; twelve thousand years ago, what is now moist tundra was a drier, grassier, landscape grazed by animals that included bison, but caribou bones are what scientists are finding at Raven Bluff so far. 

Another established scientific hypothesis being tested is how the use of certain stone tools spread in North America. The lower levels of the site produced a very significant find of a roughly 12,000 year-old fluted projectile point base, marking the first time such a tool has been definitely dated in the north.