History through obsidian topic of Chautauqua at SFI
From our weekly issue dated August 05, 2009
On Friday, Aug. 7 in Selma, archaeologist Dennis Jenkins will discuss the invaluable information about our culture stored within nature in Obsidian: History through the Volcanic Glass Window.
This free, public program will begin at 7 p.m. at 1241 Illinois River Road, Selma, as Siskiyou Field Institute will host this Oregon Chautauqua from the Oregon Council for the Humanities.
Flows of obsidian, a natural glass produced by many volcanoes in Oregon, contain a unique chemical signature that enables archaeologists to trace artifacts to the volcano of origin.
Obsidian is also an unstable mineral that begins absorbing molecular water soon after a fresh surface is exposed to the atmosphere, a process that produces a detectible rind that thickens at a predictable rate under various site conditions, producing a “hydration clock” that tells the age of each artifact and flake.
Obsidian artifacts yield a treasure-trove of information about prehistoric lifeways and the development of sociopolitical areas in central Oregon across 15,000 years of prehistory. Jenkins will present a fascinating look at the trail of information left by this beautiful volcanic glass.
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