A not so isolated fringe:Dutch later prehistoric (c. 2200 BCE-AD 0) bronze alloy networks from compositional analyses on metals and corrosion layers

Using a corpus of over 370 compositional analyses of Dutch Bronze Age and Iron Age (c. 2000 BCE AD 0) copper alloy artefacts, long-term patterns in the types of alloys used for specific bronze objects are identified. As the Low Countries are devoid of copper ores and alloying elements, a combination of typo(chrono) logical and compositional analysis is used to identify through which European contact networks (such as Atlantic, Central European or Nordic exchange networks) these alloys were obtained. We employ a methodology that (following Bray et al., 2015) defines alloy groups by presence of As, Sb, Ag and Ni over 0.1 %wt, but expanded this classification to include Pb and to track high-impurity (>1%wt) alloys. Due to interfering soil-derived iron hydroxides, and preferent dissolution of copper from the objects’ surface, the determination of tin is in most cases overestimated when using p-XRF, so Sn was not systematically reviewed. Objects were assigned a calendar age in years BCE to facilitate chronological sorting. Using this classification, we could show how different alloys (using different base ores) were used in different periods, and in different combinations. Moreover, particular alloys were used for different groups of functional types of objects. Also, we show diachronic differences in the influx of new (or less frequently mixed) alloys and chronological trends in the substitution of As by Sn as main alloying element in the Early Bronze Age as well as the rise of leaded alloys at the close of the Bronze Age. Combining information on the composition of the objects with their typological traits, allowed us to reconstruct the scales and geographic scopes of the European contact networks in which the copper alloys used throughout later prehistory were obtained

Hunting colours: origin and reuse of glass tesserae from the Wierum terp

Mosaic glass tesserae were imported to Dutch sites during the Early Medieval period, probably to address the demand for coloured glass needed in ornamental bead manufacture. Although challenging, because of the uncertainty of the material’s context, the Wierum Early Medieval collection represents an extraordinary opportunity, being the most significant find of glass tesserae in the Netherlands to date. The combined use of electron microprobe analysis (EMPA) and hand-held X-ray fluorescence spectrometry (HH XRF) allowed us to examine glass tesserae and other vitreous samples from the site. Low levels for magnesium and potassium oxides (<1.5 wt%) and the chemical components linked with the silica source, fluxes, opacifiers and chromophores are compatible with an older Roman soda-lime-silica glass production. Alumina and calcium oxide contents together with the adoption of antimony-based opacifiers are compatible with mosaic tesserae of a first to third century AD Roman tradition. We assume that these tesserae were collected during the spoliation of a lavish building and reused for glass objects produced locally. The hypothesis seems to be confirmed by the presence in the collection of tesserae still embedded in mortar, stone tesserae fragments and a rounded fragment of Egyptian blue

A new French Tréboul spearhead found in The Netherlands:the case of the Goor find

Report on the discovery of a Tréboul spearhead (of NW French origin) from the vicinity of Goor. Its composition was determined witn pXRF (Cu 89%, Sn 9,7%, As 0,8%, minor contributions of Sb, Pb and Ni) and consistent with assemblages in NW France. Wood from the socket was extracted and identified as Ash (Fraxinus excelsior) and 14C dated to 1609-1456 BCE, which fits the typological attribuition to the MBA-A