ORGANIC RESOURCES AT THE IRON AGE DÜRRNBERG SALT‐MINE (HALLEIN,AUSTRIA)—LONG‐DISTANCE TRADE OR LOCAL SOURCES?*

Remarkable preservation circumstances for organic material at the Iron Age salt‐mine on the Dürrnberg Mountain offered the opportunity to analyse a large amount of wood and human faeces. One aim of the studies was to discover the origin of the important resources food and wood. Concerning the question of ‘the linking role of the Alps in past cultures’, the archaeobotanical record proves intracultural but no intercultural connections at this place in Celtic times. The preliminary results show that the Dürrnberg population used differentiated strategies to manage a continuous food and wood supply. While the wood supply was based on the management of local sources, the food supply had to be linked into a regional and long‐distance trade system.     

THE MELTING FURNACE OF THE DERRIÈRE SAIROCHE GLASSWORKS (COURT,SWISS JURA): HEAT‐INDUCED MINERALOGICAL TRANSFORMATIONS AND THEIR TECHNOLOGICAL SIGNIFICANCE*

Seventy‐one oriented specimens from the pre‐industrial reverberatory melting furnace of the Derrière Sairoche glassworks (Swiss Jura) were analysed. During its period of activity (1699–1714), this glassworks produced wood‐ash glass of liquidus temperatures up to 1400°C. Textural and mineralogical features point to temperatures around 1500°C in the melting chamber. The inner structure of the furnace shows chemical contamination due to ash, molten glass and furnace gases. These results reveal the pyrotechnological know‐how of the glassmakers and prove that the thermal performance of this kind of furnace has been under‐evaluated in the past.     

THE CHARACTERIZATION OF WATERLOGGED ARCHAEOLOGICAL WOOD: THE THREE ROMAN SHIPS FOUND IN NAPLES (ITALY)*

Three apparently well‐preserved shipwrecks dating back to Roman times were brought to light near Piazza Municipio in Naples (Italy), during the excavation for the construction of Line 1 of the subway. The shipwrecks were covered by marine sand and silt, below the water table. In order to establish the nature and the extent of wood degradation and, therefore, determine how best to preserve the shipwrecks, a diagnostic investigation was carried out. The study involved the identification of wood species, chemical characterization of the residue component and physical and micro‐morphological characterization.     

DATA ON 61 CHEMICAL ELEMENTS FOR THE CHARACTERIZATION OF THREE MAJOR GLASS COMPOSITIONS IN LATE ANTIQUITY AND THE MIDDLE AGES

Sets of 20 soda ash, 16 soda lime and 23 wood ash glasses mainly from excavations in Europe were analysed by microprobe and LA–ICP‐MS for 61 elements and are presented as average concentrations with standard deviations. Concentrations of sodium, potassium and magnesium allow the major glass type to be identified. Specific compositions of the raw materials of glass production indicate certain sources, technical processes and ages. Heavy minerals etc. of quartz sands contain rare earth elements (REE) from crustal fractionations that are different for the three major glass types. Accumulations of P, B, Ba, Mn and K in wood from soils by organic processes can characterize glass from certain regions.     

X‐RAY SUB‐MICRON TOMOGRAPHY AS A TOOL FOR THE STUDY OF ARCHAEOLOGICAL WOOD PRESERVED THROUGH THE CORROSION OF METAL OBJECTS

Wood preserved in the corrosion layer of two early medieval iron objects was examined using X‐ray tomography. A state‐of‐the art multi‐resolution X‐ray tomography set‐up ( http://www.ugct.ugent.be ) provided virtual cross‐sections of the archaeological wood samples at sub‐micron resolution. These were compared with scans of samples of similar modern wood. These scans demonstrate the power of sub‐micron X‐ray tomography for wood identification, although the process of mineralization pushes this technique to its limits. Furthermore, this technique facilitated appraisal of the mineral content of the archaeological wood, which is useful in selecting the most appropriate strategy for the (preventative) conservation of the archaeological object.