On the validity of archeomagnetic dating method in Korea: a case study

초록

An archeomagnetic study has been performed for six archeological relics of the Proto-Three Kingdoms period excavated in Jungdo Island, South Korea. Among a total of 90 samples from hearths remains of six dwelling sites, the characteristic remanent magnetization components were isolated from 70 samples using the progressive alternating field demagnetizations and considered to record faithfully a thermoremanent magnetization at the timing of the last cooling of the hearths. Two different approaches were made to determine the archeomagnetic ages: One is the conventional method using the relocated paleosecular variation (PSV) curve obtained from southwestern Japan. The other method adopts a Matlab archaeo_dating tool using a Bayesian statistics with global geomagnetic field prediction model (ARCH3K.1). Both archeomagnetic ages using two individual dating methods generally overlapped with the radiocarbon age ranges for each sites. However, no systematic relationship between archeomagnetic ages and radiocarbon ages was observed, implying that neither the relocated Japanese PSV data nor the global model accurately represent the Korean secular variation during the archeological period of this study. At present, archeomagnetic dating in Korea should be carefully applied in conjunction with other dating methods on the consideration of archeological context.

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