Estimation of the thermal history, usage and age of a Korean cast iron artifact

Abstract

Iron is considered to have played a crucial role in the rise and subsequent development of the first Korean states. Archaeological study on the history of iron production in Korea, however, is plagued with uncertainties due primarily to lack of metallurgical work and reliable chronological framework. The present study has examined a cast iron artifact in terms of its microstructure and its date of manufacture. The artifact was excavated from a burial site of the former Kaya kingdom located at the modern city of Kimhae. The artifact is found to hold unique microstructural characteristics indicating employment of a long thermal treatment applied on white cast iron. It also includes a considerable amount of arsenic, suggesting the establishment of trade routes between two ancient kingdoms, Kaya and Silla. The C-14 age determined through accelerator mass spectrometry on carbon material extracted from the artifact, as well as the thermoluminescence age of a shard sample, were in fairly good agreement with the relative ages of their excavation sites estimated on typological grounds, i.e., the 4th century AD. These results demonstrate the potential importance of metallurgical examination, if combined with reliable chronology, in the characterization of specific iron technologies practiced in ancient societies. The results also support the use of radiocarbon dating on C from iron artifacts as a potential method of establishing a reliable chronology in Korea.