The history of the United States cent revealed through copper isotope fractionation

Ryan Mathur, Spencer Titley, Garret Hart, Marc Wilson, Michael Davignon, Caitlan Zlatos

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


Copper isotope fractionation in United States cents traces changes in the source of copper and identifies historical events. Application of copper isotopes as a geochemical tracer requires consistent isotopic signatures of the ores and refined metals. Overlapping isotopic signatures of crushed ores, chalcocite and refined metal extracted from Morenci, Arizona indicate modern mining processes that produce distinguishable single ore deposit geochemical signatures. The coincidence of copper isotope ratios in metals and ore deposits also exists within the United States cents analyzed here. Specifically, historical records confirm two different sources for copper in cents from 1800 through 1867. The copper isotope composition of the 1828, 1830, 1836, 1838 and 1843 cents coincides with the Cornwall ores of England, and cents post 1850 (1859, 1862) correspond with the Michigan ores of the United States. Three of the thirty-six post 1867 cents measured possess fractionated copper isotope ratios and indicate the change in source of copper for the United States cent.

Original languageEnglish (US)
Pages (from-to)430-433
Number of pages4
JournalJournal of Archaeological Science
Issue number2
StatePublished - Feb 2009

All Science Journal Classification (ASJC) codes

  • Archaeology
  • Archaeology


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