Abstract

The history of iron is the story of the continuous endeavour of metallurgists to attain a practical mastery over the carbon content of the iron, without knowing that it contained any carbon, or what the effects of carbon are... . Thus, the words of T.T. Read (1934) remind us that in addition to the usual fuels, charcoal and coal, such carbonaceous materials as dogs' blood, pigeons' droppings, rice husks and humans have all been used in the manufacture of iron implements, while the mixing of irons of different types and/or sources has also been a common practice. A detailed knowledge of an artifact's metallurgical history is therefore a pre-requisite for obtaining a meaningful date. Fortunately, this is commonly available, and careful metallography can often give strong clues into the artifact's mode of manufacture, and hence reliability of the date obtained. A number of iron artifacts have been analyzed, many of which give dates consistent with their metallurgical/historical context: a few, however, have yielded misleading dates. Some of these can be resolved by metallographic inspection, chemical analyses or knowledge of the metallurgical context of the site. In addition, the small sample size (£5g.) capability of accelerator radiocarbon dating permits multiple analyses in some cases that can further help elucidate the history of an artifact. In other cases, inconclusive results are obtained. Examples of samples analyzed at the Isotrace Laboratory will illustrate these capabilities and limitations.