What is this Doing Here?

Obsidian in the Kodiak Archipelago

By Dr. Jeff Raisic, Curator of Archaeological Collections, University of Alaska Museum

 
Throughout history volcanic glass has been valued.   Also known as obsidian, people sought this material for tool making, using it to fashion knives, scrapers, and points.  The edges of obsidian tools are exceptionally sharp; they can be finer than a modern surgical scalpel. And it probably mattered that obsidian can be quite beautiful—glassy, and smooth, sometimes transparent, often a deep black, other times a vibrant orange or red marked with spots and whirling patterns.

Today archaeologists prize obsidian for its ability to shed light on ancient patterns of travel and trade.  This material can be sourced.  Natural deposits of obsidian are rare and each deposit has a unique combination of trace chemicals – minute amounts of strange-sounding elements such as niobium, yttrium, and rubidium—which provide a fingerprint for that source. Obsidian artifacts found in archaeological sites can be examined to determine their precise fingerprints and then compared to a catalog of source fingerprints. When there is a match, archaeologists know the origin of the obsidian used to create an artifact. Often the obsidian has been carried hundreds of miles.

This spring, obsidian artifacts found in Kodiak sites were examined at the Alutiiq Museum with a portable X-ray fluorescence analyzer. The machine looks like an overgrown Star Trek phaser, but it is not science fiction.  It quickly, and without any impact to the artifact, measures trace element composition.

The results of this brief study showed that almost all of the obsidian (14 of the 16 artifacts) found in Kodiak and Afognak Island sites originated from Okmok Volcano on Umnak Island in the Aleutian chain, some 675 miles distant. One Kodiak artifact is from a poorly known source in the Aleutian Islands, probably associated with Makushin Volcano near Dutch Harbor (590 miles distant). Perhaps the most surprising find was an obsidian point from the Uyak site on the northwest coast of Kodiak Island, which matched the Batza Tena obsidian source in northwestern Alaska. Although this source is actually the closest (570 miles) of the three sources identified, the transport of this artifact would have required a long, overland route, or a much longer river, coast and land route of 1500 miles or more.  What’s more, this find demonstrates contact with interior, Athapaskan-speaking groups 1200 years ago.  It highlights the cosmopolitan nature of Kodiak’s prehistoric societies.  People adeptly navigated not only oceans and rivers, but had linguistic and diplomatic skills necessary to cultivate international relationships.

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