境矢石遺跡出土鉄器の非破壊分析

Non-destructive analyses of iron artifacts excavated from Sakai-Yaishi archaeological site

三ツ井 誠一郎  

Mitsui, Seiichiro

鳥取県南部町境矢石遺跡からは見掛け上保存状態の良い考古学的鉄製品が多数出土している。これら出土した鉄製品の腐食状態を把握するため、蛍光エックス線(XRF)及びエックス線回折(XRD)、エックス線コンピュータトモグラフィ(X線CT)を用いた非破壊分析を行った。また比較のため、保存状態の悪い博労町遺跡から出土した鉄製品についてもあわせて分析を行った。その結果、境矢石遺跡と博労町遺跡の鉄製遺物の腐食状態の違いは両遺跡の立地場所の違い、すなわち丘陵部と海浜部における埋蔵環境条件の違い、を反映していることが示唆された。

A number of ancient iron artifacts in apparently well-preserved state were excavated from Sakai-Yaishi archaeological site in Nambu Town, Tottori Prefecture. To obtain detailed information on corrosion state of the iron artifacts, we analysed corrosion depths with a X-ray Computer Tomography (X-ray CT) and corrosion products with a portable X-ray diffractometer equipped with X-ray fluorescence spectrometer (XRD/XRF). For comparison, a poor-preserved iron artifact excavated from Bakurou-Machi archaeological site in Bakurou Town also analysed. The results imply that the difference in the corrosion states of the iron artifacts between Sakai-Yaishi and Bakurou-Machi archaeological sites reflects a difference in locations between both archaeological sites, that is a difference in burial environmental conditions between a hillside and a beachside.