Sana Shilstein

Identifying a Roman Casting Pit at Tel Dor, Israel: Integrating Field and Laboratory Research

Abstract The functional identification of industrial features is difficult when few characteristic artifacts are preserved. We studied a Roman-period pyrotechnological feature at Tel Dor, Israel, where the only possibly diagnostic ceramic artifacts were found in fill between the walls and above the floor, rendering their association with the feature itself uncertain. The ceramic artifacts included coarse slabs and fragments of utilitarian vessels, some vitrified with adhering bronze droplets or slag-like residues. Analysis of the sediments within and around the industrial feature, using an X-ray fluorescence spectrometer on-site, revealed high concentrations of copper and lead, indicating metallurgical activity. Lead isotope analyses showed that the slag-like residue adhering to a ceramic fragment had the same isotopic values as the sediments, implying that the fragment was associated with the activities carried out in the feature. Microscopic and chemical analyses of the slag-like residue demonstrated that it was produced from melting leaded bronze. Some of the ceramic fragments contained elongated impressions on their inner surfaces, similar to those of casting molds found at other sites. We propose that the feature was used as a casting pit for bronze objects.

Neutron diffraction study of Levantine Middle Bronze Age cast axes

A neutron diffraction study on 6 Middle Bronze Age axes, cast from tin bronze or from arsenical copper, has been carried out using the ENGIN-X beamline at ISIS. The gauge volumes dimensions were 4x4x10mm3; data were collected along the lengths of the objects in their central parts, as well as on the blades, in order to establish the spatial phase contents. Average phase fractions were determined by Rietveld analysis. The main phases identified were solid solutions, corrosion phases and metallic Pb inclusions. We have observed distributions of lattice constants of the solid solutions Cu-Sn, and Cu-As inside each gauge volume in the central parts of the axes due to segregation, or liquation effects. However, the Cu-Sn variations were significantly less pronounced in comparison with typical inhomogeneity effects in as cast objects. The results indicate that the studied Middle Bronze Age axes were probably treated at high temperatures for homogenization necessary for generating sufficient hardness, especially on the blades.