Assessing the analytical capabilities of handheld laser‐induced breakdown spectroscopy ( hLIBS ) on corroded iron objects of possible meteoritic origin

Abstract Despite meteorites having been recognized as the source of iron in some ancient iron artifacts, few archeological irons have been analyzed so far, as invasive methods are precluded. In this work, four iron knives and one axe collected near Guelmime and Imilchil (Morocco) were investigated by advanced analytical techniques, including handheld laser‐induced breakdown spectroscopy (hLIBS), still not yet widely used, and portable X‐ray fluorescence (pXRF). The analyzed objects are undated iron findings recovered without an archeological context and represent test cases for assessing the analytical capabilities of hLIBS on corroded iron objects of possible meteoritic origin. Major and trace element analyses, internal stratigraphy by depth profiling, and microscale compositional mapping have been performed, which allowed assessment of the sample composition, heterogeneity, and corrosion. One of the five specimens studied appeared to be made of meteoritic iron. The relative uncorroded state of this specimen, when compared to Bronze Age irons, enabled investigation of the effect of forging on the composition, especially the mobility of Ni. In particular, the reliability of hLIBS‐acquired analytical data for the major elements Fe and Ni and the trace elements Ge and Au was shown. As well, a possible source relationship of sample #5 with NWA 859 (Taza)/Oglat Sidi Ali meteorite was discussed and proposed, based on the chemical variations ascribed to the interplay of primordial heterogeneity and the introduction of carbon upon forging and corrosion. Furthermore, the analytical limitations of the hLIBS technique were suggested not to be instrumental, but due to the heterogeneity of natural specimens, confirming that hLIBS represents a robust analytical tool for future field archeology and archeometric studies.