With National Science Foundation support, Professor Marvin Rowe, his graduate student, Ph.D. candidate Karen Steelman, and their archaeological and accelerator mass spectrometry colleagues will conduct research attempting to demonstrate that plasma-chemical extraction (PCE) of organic carbon can be accomplished virtually non-destructively for many sorts of perishable archaeological artifacts. The team brings expertise developed over the past decade and a half, a time in which Dr. Rowe and his graduate students perfected the PCE technique for removal of minute amounts (about 0.1 milligrams of carbon) organic carbon from rock paintings to allow accelerator mass spectrometric radiocarbon dating of those images. That laboratory remains the sole laboratory capable of direct dates on pictographs independent of the pigments used. Advantages of non-destructive analysis of rare and valuable archaeological artifacts are noteworthy and are more or less obvious. Many archaeological samples are inherently rare and precious. For example, four notable examples are the Shroud of Turin, the Vinland map, the Kenewick man and the 'Iceman'. Non-destructive dates and non-destructive stable isotopic determinations (d13C) would provide useful information on such artifacts without destroying even small portions of these objects. And archaeologists often find preserved perishable artifacts, e.g., textiles, baskets, wood carvings, seeds, or papyri, that need require study, especially dating. But because of their rarity, they should be conserved, curated and displayed. Their destruction presents both practical and ethical problems for archaeologists. In all these cases, non-destructive radiocarbon dates and stable carbon isotopic measurements would provide data without destruction of even a small part of the artifact under question. We have obtained various samples from the Fourth International Radiocarbon Intercomparison study to test the PCE radiocarbon and stable isotopic analyzes for accuracy and degree of non-destructiveness. Other samples have also been obtained for evaluating the accuracy of radiocarbon dates and stable carbon isotopic measurements with non-destructive PCE. There has already been some interest expressed by archaeologists about the possibility of non-destructive radiocarbon dates. With National Science Foundation support, we thus hope to demonstrate beyond question that we can produce accurate dates and d13C values utilizing plasma-chemical extraction of minute amounts of carbon.
