National Park Service U.S. Department of the Interior

Yukon-Charley Rivers National Preserve

Obsidian Journeys: Prehistoric Travel and Trade Trails through the Preserve

National Park Service archeologists conducting field surveys near the Charley River headwaters

Archaeologists from Yukon-Charley Rivers Most derive from the Batza Tena source on While some obsidian can be distinguished National Preserve have begun an effort to the Koyukuk River, 500 km (310 mi) away, visually, the most reliable method of geochemically analyze obsidian artifacts and the Wiki Peaks source in the Wrangell obsidian sourcing involves using X-ray from the preserve. Obsidian is a volcanic Mountains, 320 km (200 mi) away. These fluorescence (XRF) or Inductively Coupled glass that was used in the past to manu- data have potential to reveal changing trade Plasma - Mass Spectrometry (ICP-MS) to facture stone tools like projectile points and travel patterns through time and shed detect the combination and proportions and scrapers. Chemical signatures from light on prehistoric territoriality. of trace elements. Alaskan sources can be obsidian artifacts are matched with source differentiated from one another using such signatures to pinpoint the origin of the raw Formation of Obsidian elements as iron, rubidium, strontium, material used for the tool. Obsidian is a volcanic glass that lacks a zirconium and yttrium. With the XRF and crystal lattice structure because it formed ICP-MS technology on hand, researchers So far, approximately 100 obsidian artifacts from a magma or lava which cooled ex- have developed databases that keep records from Yukon-Charley have been analyzed. tremely rapidly. This geological character- of all sourced obsidian. In all of Alaska, five istic makes obsidian a perfect raw material obsidian sources are known and more than for stone tool manufacture because it flakes 20 sources are represented by archaeo- easily and predictably. When this liquid logical samples from unknown geological rock cools, it traps the elements present sources. By finding more samples from in the molten liquid. These trace elements unknown sources archaeologists hope to occur in volcanic glass in variable amounts, determine an area where the source is likely thereby creating a unique chemical signa- to be located. As in other parts of the state, ture for any particular volcanic flow. obsidian from Batza Tena and Wiki Peak sources is most commonly encountered at Obsidian Sourcing archaeological sites in the park, although Determining this unique chemical signa- a few unknown sources were also discov- ture lets scientists know where the raw ered. An obsidian hide scraper from an archaeological site in the Yukon-Charley National Preserve material for the stone tool was obtained. Batza Tena The Batza Tena source is in north-central interior Alaska along the Koyukuk River. Though reports of this source were made by the U.S. Geological Survey as early as 1900, it was not until 1967 that W.W. Patton definitively established its true location. Artifacts from this source are found across the state (excluding the Aleutian Islands and Southeast Alaska) due to its excellent quality and central location.

Wiki Peak The Wiki Peak obsidian source is in the Nutzotin Mountains (Wrangell-St Elias National Park). An investigation of the Wiki Peak obsidian source was conducted in the past decade, and over 65 archaeologi- cal sites were recorded in a survey of the immediate area. The high concentration of sites is typical for other obsidian source areas in Alaska and northwest Canada, with few exceptions.

Unknown Sources Map showing the distribution of archaeological sites with obsidian and the location of the two largest Prehistoric people who lived or traveled in interior Alaskan obsidian sources. Site locations are approximate the Yukon-Charley National Preserve knew of at least three more obsidian sources that we have yet to find. One piece of obsidian Results of Obsidian Sourcing in the with the land and the resources available to from around the Seventymile River was Yukon-Charley National Preserve them. attributed to Group A’, a source with an Practically all of the sites containing obsid- as-yet undiscovered location. Flakes from ian in the park were found on elevated Unfortunately, the ages of the sites which this source were previously encountered in ridges ideal for hunting purposes. While contributed the obsidian samples remain great quantity at the Ringling archaeologi- most sites had obsidian from one of the unknown. This is due to the fact that most cal site 280 km (174 mi) south of the park. two main sources, several sites contained obsidian so far has been found in high Also surprising, ten flakes from an un- obsidian that came from two different lookout, surface sites where preservation known obsidian source refered to as “Fire directions, as shown on the map. This of organic materials that could be dated Guard Station” were found at an archaeo- might indicate sites that were incorpo- (by radiocarbon methods, for example) is logical site right near the National Park rated into a larger network and served as practically non-existent. However, archae- Service Headquarters in Eagle. Finally, one places where people from different regions ologists speculate that some sites were oc- piece of obsidian found on the Dimond came together. Chemical sourcing has also cupied perhaps as early as 8,000 years ago Fork of the Seventymile was attributed shown that people living along, or traveling based on characteristic stone tool forms. to an unknown and unnamed obsidian through, the Yukon-Charley Rivers region source. obtained more obsidian from Batza Tena This study is but a small component of a than from Wiki Peak. This is interesting, much larger research project that is under- because the Wiki Peak source is closer to way. Collaboration between the National the park and one would expect less obsid- Park Service, University of Alaska Museum ian from a more distant source. Perhaps the and the Smithsonian Institution constantly Yukon River was a more convenient route produces new analyses to be added to for trading purposes (by boat, dog sled or the database of sourced archaeological by foot). Travel from Wiki Peak would have obsidian in Alaska. As research continues, been somewhat more challenging due to obsidian density maps will show how the rugged terrain. Alternatively, Batza Tena widespread the obsidian is and along which obsidian could be prevalent due to the routes the raw material traveled. Despite presence of more established trade rela- the small number of samples, this prelimi- tionships with people to the west than with nary investigation already hints at a much people to the south. Presence of obsidian broader exchange network and/or raw from unknown obsidian sources shows material procurement range than previ- A small obsidian flake can be evidence of large that people were exceptionally familiar social networks ously realized.