U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
 
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Excavations at the Raven Bluff Site

Central Yukon Field Office

Arcticle from BLM Frontiers, Issue 108:

Raven Bluff: An Archaeologist's Dream

The Mother Lode. The Big Kahuna. An Alaska archaeologist’s dream site. 

When BLM Central Yukon Field Office archaeologist Bill Hedman ponders such a find, his thoughts don’t stop at a treasure trove of artifacts covering thousands of years of human history. His ideal site would also have thick soil deposition to help differentiate artifacts from different time periods. There’d be lots of bone, too, or other organic material for dating the artifacts. Oh, and add a nice breeze to keep the swarms of arctic mosquitoes down.

It’s a long list, but Hedman thinks he’s found just such a site next to the Kivalina River, a 60-mile-long river that begins in the DeLong Mountains of the western Brooks Range and flows southwest to Kivalina Lagoon in the Chukchi Sea. The site is approximately 100 air miles north of Kotzebue.

Hedman has christened the new site "Raven Bluff." According to Hedman, only a handful of sites this old have been found in northern Alaska. He’s hoping Raven Bluff’s unusually long record of human use will shed new light on the earliest inhabitants of North America.

Hedman and a colleague discovered Raven Bluff in 2007 during the first year of a three-year archaeological survey and testing project centered on the Kivalina River. One evening a low, grassy knoll caught his attention. "It looked really prominent and isolated out here, surrounded by mostly flat, mundane tundra with the river right up against it," he recalls. "We got over there, climbed up onto the bluff, and just started finding [stone] flakes. They were everywhere!" A few quick pits revealed that, unlike the other sites they’d seen, artifacts were not confined to the surface. Many more appeared to lay buried in the soil.

Hedman returned with more help in 2008. He and his crew dug five or six pits that summer. In all but one location, they were stopped close to the surface by frozen ground. At one pit, however, they dug deeper than a meter. The bottom of that pit contained abundant bone and tool-making debris in soil that was eventually dated at approximately 10,000 years old.

The type and age of artifacts in that single pit already pointed to a significant archeological find. But was the Raven Bluff site confined to a small area, or was there more to find elsewhere on the knoll? To find out, Hedman returned to the site with another crew for two weeks last summer. Due to the warmer weather, the crew was able to dig deeper at a number of carefully surveyed locations across the knoll.

Standing next to a meter-deep pit on the knoll’s crest, Hedman gazes down at the Kivalina River, which rushes out of the rugged DeLong Mountains behind him and flows past this year’s camp, a jumble of yellow tents on a gravel bar, before braiding across a vast, tundra-covered plain.

"What we think is going on here is that we have a landform that’s oriented perpendicular to the prevailing summer winds," Hedman says. "Summer is the season in which soils are deposited by wind. So we’ve got wind actually carrying [river] sediment up over the edge of this bluff and laying it down in different places across the landform."

"You’ve got material being buried quickly, so that when the next person comes along and makes a tool, there’s already three centimeters of soil on the ground that they’re depositing their tools on."

On the face of it, soil deposition wouldn’t seem to hold much allure for archaeologists eager to find artifacts. In fact, digging it out of the way requires tiring shovel work. However, if the Raven Bluff site holds the significance that Hedman thinks it does, the site’s steady accumulation of soil over hundreds and thousands of years may prove nearly as important as the rich collection of artifacts he’s already finding.

That’s because the frequent and thick buildup of soil helps establish the order in which artifacts were deposited at a site. This is especially true in Alaska, where the seasonal freeze-thaw cycle can move artifacts and other material out of sequence as they go up and down through the soil column.

The next and critical step—determining the age of soil layers and the artifacts found in them—requires recovering bone or other organic material, often charcoal, from the soil. These items can be analyzed with Carbon-14 dating. Here too, the Raven Bluff site is proving unusually rich.

Hedman is still awaiting results from laboratory analysis of artifacts found this summer even though early indications suggest that Raven Bluff and its thick layers of soil hold important information about a human presence in North America.

Raven Bluff indeed appears to be an archaeologist’s dream site.


Media

Wow A Bi-Face! BLM Archaeologist Bill Hedman finds a bi-face (prehistoric stone tool) and explains about BLM's Archaeology program in the far north. Video by Frontier Scientists.

Time Travel in the Alaskan Arctic. BLM Archaeologist Bill Hedman talks about he Raven Bluff site and the partnerships the BLM has with teachers. Video by Frontier Scientists.


 
Last updated: 12-19-2012