Brown Bag Lecture Series: Dr. Ruth Ann Armitage, Associate Professor/Department of Chemistry, Eastern Michigan University, "Plasmas for Radiocarbon Dating Microgram-Sized Samples"


Nov
05
2009

  • Host Department: Museum of Anthropology
  • Date: 11/05/2009
  • Time: 12:00PM - 1:00PM
  • Location: Room 2009 Ruthven Museums
  • Contact Information: Judy Hartsuff judyhart@umich.edu 734/764-0485
  • Description: The development of radiocarbon dating marked a fundamental shift in the practice of archaeology. Accelerator mass spectrometry further revolutionized the amount of material needed to obtain a radiocarbon date, and thus has had a profound impact on what can be dated. However, the standard methods of preparing samples for AMS dating are destructive. We utilize a plasma preparation process whereby only the very surface – on the order of 1/10 of a milligram – of an organic object is removed through a gentle chemical reaction, producing carbon dioxide that can be AMS dated. As the object is generally unchanged after exposure to the plasma, we call this “nondestructive” radiocarbon dating. The plasma process can also be applied to residues, and was first utilized for preparing samples of rock paintings for AMS dating. This talk will describe how the plasma process works, results so far, and some of the capabilities and limitations of this unique approach to a complex problem.