鉄サビの放射性炭素年代測定のための基礎実験(II) [in Japanese] Preparation of iron rust samples for radiocarbon dating with AMS (II) [in Japanese]
Access this Article
It is well known that ages of ancient iron artifacts can be measured by using carbon contained in the iron artifacts. As a simple method of carbon extraction from iron artifacts, a normal quartz tube is used for metal iron combustion at the temperature of 1000℃ for about 15 hrs. We tested the quartz tube method of metal iron combustion successfully for metal iron in fine fragment forms and reported the results previously. In Japan, iron rust samples are commonly excavated from archeological sites of the Kofun period and after. We have tested to collect carbon from iron rust samples successfully by the quartz tube method of iron-rust combustion at 850℃ for 3 hr. We have experienced that quartz tubes were broken twice during combustion: at 900℃ for 8 hr and at 850℃ for 3 hr. 14C age, 524±25 BP, was obtained for an iron rust sample from a ruin of Fe manufacturing site worked at 1850s in Saga city, Saga Prefecture, Japan. The 14C age was too old compared with the estimated age of the site. 14C ages were also obtained for three rusty nail samples as 2949 -3244 BP. The results suggested a possibility of modern carbon contamination in considerable amount during rust process of metal iron that was produced by using coal as a heating fuel as well as material to reduce iron oxide ore.
名古屋大学加速器質量分析計業績報告書 (26), 150-155, 2015-03