9:30 AM - 9:45 AM
[SEM18-03] Reconstruction of full-vector archaeomagnetic reference curve in East Asia from 200 CE to 1100 CE
Keywords:Archaeointensity, Reference curve, East Asia, Tsunakawa-Shaw method, Old kiln
This study carried out the reconstruction of the archaeointensity using the Tsunakawa-Shaw method for a large number of samples of baked clay belonging to different ages from archaeological relics in Osaka Prefecture mainly, and constructs a dataset and the reference curve of archaeointensity in Japan (East Asia).
As the result, we estimated archaeointensities from 98 specimens belonging to 39 relics. We screened these data, compiled them for each pottery sequence, and finally obtained 10 mean intensity values of the pottery sequence level. All of the mean intensity values satisfy the selection criteria, which indicates that they have sufficient reliability. It is notable that these newly estimated archaeointensity values are lower than those in previous studies in Japan. On the other hand, new archaeointensity values show a harmonic trend in the archaeointensity data set obtained by the IZZI-Thellier method reported recently in Korea. We combined the dataset of Japan newly obtained in this study and the dataset in Korea, and drew an interpolation curve to construct an archaeointensity reference curve covering from around 200 CE to around 1100 CE in East Asia. This reference curve includes events of decrease and increase of archaeointensity occurred at around 600 CE and around 950 CE. The trends of rapid decrease and increase in intensity are a characteristic pattern of the intensity variation found for the first time in this study.