Northern Oklahoma

Building Bonds with Chemistry in Northern Oklahoma


Spring 2016 Seminar: Ruth Ann Armitage

Posted by Natalie Rebacz on April 11, 2016 at 2:00 PM

Northern Oklahoma ACS is pleased to announce the spring seminar event in Ponca City, OK. Dr. Ruth Ann Armitage, from Eastern Michigan University will give her talk, "Archaeological Chemistry of Rock Paintings: Radiocarbon Dating and Chemical Analysis," on Tuesday, April 26th, at Zino's Restaurant.  


While still a chemistry student at Thiel College in Pennsylvania, Ruth Ann Armitage participated in an archaeological field school and confirmed her desire to combine the seemingly disparate disciplines of archaeology and chemistry. She completed a Ph.D. in Analytical Chemistry at Texas A&M University on radiocarbon dating of charcoal-pigmented rock paintings and has worked with archaeologists at historic and prehistoric sites around the world. Dr. Armitage, Professor of Chemistry at Eastern Michigan University, and her students develop mass spectrometry methods to characterize archaeological materials, including rock paintings, dyes in ancient textiles, and ceramic residues to help archaeologists understand our ancient past.


Archaeological Chemistry of Rock Paintings: Radiocarbon Dating and Chemical Analysis

Rock paintings, or pictographs, are unique cultural remains that are difficult to place into archaeological contexts because they are not a part of the buried stratigraphic record of a site. Direct radiocarbon dating of the paint itself would ideally be used to determine their age. The paint is typically an inorganic pigment (iron oxides and hydroxides are common) presumably mixed with an organic binder or vehicle to make the paint flow and adhere to the rock surface. Dating rock art by conventional radiocarbon techniques would have required completely destroying the paintings; the advent of accelerator mass spectrometry (AMS) for direct measurement of 14C changed that. A plasma-chemical oxidation method was developed in the 1990s to selectively remove organic carbon from small samples of paintings, yielding CO2 for radiocarbon analysis by AMS. Some paintings contain easily recognized organic material, such as charcoal, but most do not. At EMU, we are using chromatographic and mass spectrometric methods to determine the nature of the organic material present in rock paintings, and using the plasma-chemical oxidation/AMS method to date them. Results of our work on paintings from locations around the world will be presented.

Event Details

Date Tuesday, April 26th, 2016
Venue Zino's Restaurant, 200 N 2nd St., Ponca City, OK 74601. Ph: 580-718-0100
Social Hour 6:00 pm
Dinner 6:30 pm
Seminar 7:30 pm
Cost Free for all ACS members. $10 for non-ACS members. No charge for only attending the seminar

Categories: Seminars

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