Obsidian and Trade Ancient Relations

By Dana Lepofsky 

Why study obsidian artifacts?

Archaeologists have two means for studying ancient social relations. The first is by looking for similarities in the form of artifacts (projectile points, baskets, house styles). This research is based on the assumption that shared styles indicate shared ideas and thus communication. Another way to understand past social and economic relations is to track down the origin of the raw materials used to make the artifacts recovered in archaeological sites.

Obsidian, formed by the rapid cooling of volcanic magma, is ideally suited for this second method. This is because the magma associated with each volcanic eruption is composed of a distinct combination of minerals. Once “we” figure out the distinct combination of each eruption and each volcano, it is possible to compare the make up of the artifacts we find archaeologically to this information.

There are several reasons why obsidian is a good material for tracking social relations. First, it is a highly valued raw material for artifacts because of its fine crystalline structure. It’s fine structure means both that it fractures predictably during tool-making and it will produce a razor sharp edge. But, what ultimately makes obsidian so well suited for tracking social relations is that this material is in short supply in most parts of British Columbia. Thus, in order to get obsidian, people would have either 1. lived close to the source, or 2. had social (kin?) or economic relations with the people who did live close to the source.

Where do obsidian artifacts in the Sunshine Coast region come from?

Based on just 19 obsidian artifacts, we are beginning to get a picture of ancient trade relations in this region in the last 2000 years or so. In general, obsidian in this region comes from four sources. From north to south, these are 1. Kingcome Inlet in central B.C, 2. Mt. Garibaldi in Squamish, 3. Whitewater Ridge, in central Oregon, and 4. Gregory Creek, just east of Whitewater Ridge, Oregon.

Both the Kingcome Inlet and Garibaldi obsidian are of only moderately good quality. This is because they have some larger crystals in the rock that makes the obsidian fracture less predictably during tool manufacture. Thus, all things being equal, neither of these sources should have been preferred by ancient people. That is, unless these sources were the only ones that were socially and/or economically available to them. Today, the Kingcome source is well within the territory of Kwakwakwakw First Nations, and Mt. Garibaldi is within Squamish First Nations territory.

What does all this tell us about social relations in the past?

In general, there are clear differences in the origin of the obsidian artifacts found in this region. Obsidian from Lasqueti and sites south of Powell River on the Sunshine Coast come from central Oregon and Mt. Garibaldi (Squamish). This suggests that the people who lived on Lasqueti and nearby settlements were more closely affiliated with folks further south than to the north. This pattern roughly fits with the social-linguistic break between the Tla’amin and Sechelt First Nations today.

Moving northward, the pattern changes. At Powell River sites we have both Garibaldi obsidian, but also the Kingcome Inlet source. Further north still, north of Powell River and into Desolation Sound, there is a clear preference for Kingcome obsidian. The relative abundance of Kingcome artifacts in the northern sites, and the mix of Kingcome and Garibaldi sources in the Powell River sites, suggests that there is a shift in trade (and kin?) connections somewhere around what is now Powell River. That is, it seems that people living north of Powell River looked more northerly for their social/economic relations, while the folks to the south of Powell River were more connected to the people further south.