ABSTRACTRadiocarbon (14C) ages were determined for 10 iron samples from the war booty offering site in the Nydam peat bog (SE Denmark), and compared to archaeologically inferred periods of deposition. Additional 14C measurements were carried out for modern iron standards made with charcoal of known isotopic composition to evaluate possible effects of handling. Modern iron standards give depleted 14C concentrations, compared to the initial charcoal 14C composition, and may indicate carbon fractionation effects during carbon dissolution in the iron lattice. Further studies are needed to verify if this is a common effect during iron production. 14C dating of two swords and one ax head are in comparatively good agreement with expected deposition times and indicate only small old-wood effects. In contrast, 14C dating of iron rivets from the Nydam (B) oak boat proved difficult due to corrosion with siderite (FeCO3) and conservation with wax. A step-combustion procedure was applied, using a low (∼570–600°C) temperature prior to the high (∼970–1000°C) combustion temperature for carbon extraction, aiming to remove siderite and wax before collecting the original carbon dissolved in the iron lattice. Nevertheless, measured 14C ages of the iron rivets differ by about 200–300 years from the dendro-date of the Nydam (B) oak boat they belong to, indicating persisting aging effects (e.g. old-wood, contamination with fossil carbon added during iron making and/or handling prior 14C dating). Also, a possible recycling of older iron cannot be excluded.
Interpreting 14C Measurements on 3rd–4th Century AD Iron Artifacts from Nydam, Denmark
