Monday, October 13, 2008

Tracking the geologic source of pennies

A geology professor from a small college in Pennsylvania used a mass spectrometer at the University of Arizona to track the sources of copper used in pennies, going back to 1801.

Ryan Mathur, an associate professor of geology at Juniata College, found he can correlate the copper in a penny to the mine where it was produced. The results will be published in the Journal of Archaeological Science in November.

From 1810 to 1835, the copper in pennies came from Cornwall, England. During 1835-44, it came from a variety of sources, but starting in 1845 and until 1872 most came from Michigan

After diversifying the source of copper for a number of years, the U.S. went to using copper from Montana and Arizona.

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