Abstract
The results of two different projects are discussed in this report. The first project that will be discussed was to radiocarbon date six portions of a pictograph from the Lower Pecos River Region of southwest Texas. The second project was to radiocarbon date an unusual shell mask gorget from northwest Montana. The goal of the first project was to determine which of the chemical pre-treatments used was more effective. This was done by dividing the pictograph sample into six portions and chemically pre-treating some portions. Each portion was then placed in a low-temperature, low-pressure plasma system which selectively extracts organic carbon. The organic carbon was collected and sent to Lawrence Livermore National Laboratory's Center of Accelerator Mass Spectrometry for radiocarbon dating. The purpose of the second project was to show that the plasma system described in this report can be used as an effective clean-up procedure to remove organic carbon from shell materials. Each of the three samples from a shell mask gorget were placed in a low-temperature, low-pressure plasma system where they were cleaned of extraneous organic carbon. Then, the C02 released from the reaction of phosphoric acid and the calcium carbonate shell was collected and radiocarbon dated.
Pace, Mary Fairfax Nichols (1996). Radiocarbon dating of a pictograph and a shell mask gorget. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -P32.