Burial environment of bronze halberds and bells excavated from Yanagisawa archaeological site in Nagano Prefecture

Murakami, Ryu*; Mitsui, Seiichiro  ; Hirabayashi, Akira*; Ueda, Norio*

Bronze halberds and bells in the Yayoi Period have been excavated from Yanagisawa archaeological site in Nakano City, Nagano Prefecture. This is the first case which both the artifacts were coincidentally excavated in eastern Japan and is important archaeological discovery. To identify the reason of good preservation of the artifacts, we analyzed soil and groundwater at the site as burial conditions. We also investigated migration behavior of copper, lead and tin as metal components derived from the artifacts in the surrounding soil. The results indicate that the preservation of the artifacts depends on the burial environment. In addition, we found that copper and lead migrated to the position of two meters from the pit buried the artifacts.