June 25, 2009

Obsidian provides archaeological evidence

U.S. archaeologists are using obsidian flakes left from the carving of tools to answer many questions about early human beings.

University of Washington and Smithsonian Institute archaeologists used X-ray fluorescence spectrometers to determine the origin of 131 flakes of obsidian, a volcanic glass, found at 18 sites on eight islands in the Kurils.

The flakes were found with other artifacts and dated to 2,500 to 750 years ago.

The Kuril Archipelago stretches nearly 800 miles between the Japanese island of Hokkaido and Russia's Kamchatka Peninsula and, despite their volcanic origin, there are no known sources of obsidian on the islands.

The researchers -- led by doctoral student Colby Phillips and Robert Speakman of the Smithsonian's Museum Conservation Institute -- analyzed flakes found at four locations on Hokkaido and five on Kamchatka.

Obsidian only makes up about 8 percent of the stone tools and the waste left from their manufacture, but it shows up at all sites and over all time periods, said Phillips. Here we have people living in an isolated area that is covered by fog and clouds and subject to tsunamis, volcanic eruptions and earthquakes but the fact obsidian is found across the islands shows people were proactive in maintaining ties in the prehistoric era.

The study appeared in the online edition of the Journal of Archaeological Science.