Material conveyance in the Southern California Bight: Obsidian on Alta California's Channel Islands

Abstract

Inhabited by Native Americans for at least 13,000 years, California’s Channel Islands were isolated from the adjacent mainland throughout the Quaternary. A rich archaeological record demonstrates that island peoples thrived for millennia, with access to abundant marine and terrestrial resources. Exchange with mainlanders for various goods is well documented, with long-distance material conveyance occurring very early and intensifying later in time. Obsidian was one exotic material imported to the islands from distant quarries beginning at least ∼11,750 years ago and continuing until the collapse of native exchange networks after European contact. Geochemical sourcing shows that nearly 94% of obsidian artifacts found on the islands comes from the Coso Volcanic Field located ∼300 km or more from the islands, with smaller percentages originating from sources as much as >850 km from the islands. Hydration data generally support radiocarbon dates that show that islanders participated in long-distance conveyance networks for millennia. Using these obsidian data, we examine Channel Island conveyance networks through space and time. We argue that conveyance of goods between islanders and mainlanders was a by-product primarily of social networks that functioned as sources of information, innovation, marriage partners, and strategic alliances.