In situ Measurements of Oxygen Dynamics in Unsaturated Archaeological Deposits

Oxygen is a key parameter in the degradation of archaeological material, but little is known of its dynamics in situ. In this study, 10 optical oxygen sensors placed in a 2 m deep test pit in the cultural deposits at Bryggen in Bergen have monitored oxygen concentrations every half hour for more than a year. It is shown that there is a significant spatial and temporal variation in the oxygen concentration, which is correlated to measured soil characteristics, precipitation, soil water content and degradation of organic material. In these deposits oxygen typically occurs when the air content of the soil exceeds 10–15% vol, while oxygen dissolved in infiltrating rainwater is of less importance for the supply of oxygen in the unsaturated zone.     

A New Methodology and Classification System for Describing Three‐Dimensional Particle Formats: Application to Clastic Lithic Products of Archaeological and Geological Origin

A new classification system is proposed to describe the volumetric formats of clastic lithic products of geological and archaeological origin. In order to build this operative classification, the rectangular block or cuboid is established as the standard geometric format to represent their three‐dimensional format (the X‐axis being length or long diameter, the Y‐axis being the width or intermediate diameter, and the Z‐axis being the thickness or short diameter) on a two‐dimensional diagram. To obtain this graph, each absolute coordinate (X, Y, Z) defining the prisms is projected on to an auxiliary plane with a new set of relative coordinates (x, y, z), expressed as the percentage of their sum. The projection generates a triangular diagram on which the indices of elongation and flatness are represented. A geometric transformation converting the triangular diagram into a quadrangular diagram has been produced in order to better represent the scatter points. Then, a double scale is necessary: (i) an absolute scale to quantify the indices, and (ii) a relative scale to calculate where the graphic locus is projected. This new graph also allows us to work with statistical parameters. Finally, two classic examples of applications selected from the literature are shown.     

Electron Microprobe Analysis of 9th–12th Century Islamic Glass from Córdoba,Spain

Twenty‐six samples from domestic assemblages of 9th–12th century Córdoba were subjected to electron microprobe analysis. The results reveal two main compositional types. The first, encountered in 13 of the samples, seems to result from the combination of plant ashes with high‐impurity sand, and has some contemporary parallels from Syria and Egypt. The second type is a lead–soda–silica glass, encountered in a relatively high proportion of the glasses (11 of the 26 sampled), possibly formed by the addition of lead metal to existing glasses and with very few known parallels. These are among a very small number of results available to date on the chemical composition of glasses from medieval Spain, and the presence of a high proportion of lead–soda–silica glasses is particularly interesting, possibly indicating a technological practice unique to, or originating in, the western Muslim world.     

THE EFFECT OF ACCESSIBILITY ON PRODUCTIVITY IN SPANISH MANUFACTURING FIRMS

This paper evaluates the impact of accessibility on the productivity of Spanish manufacturing firms. We suggest the use of accessibility indicators of workers and commodities, integrating transport, land use, and individual components, computing real distances or traveling times using the Spanish full road network. Estimated firms’ total factor productivity is explained as a function of the accessibility indicators and additional control variables. Results evidence the crucial role on firms’ productivity to the accessibility of commodities and to a slightly lesser extent the workers.