The Early Bronze Age settlement of Fidvár,Vráble (Slovakia): reconstructing prehistoric settlement patterns using portable XRF

This paper presents first results of chemical analyses of sediment samples from the Early Bronze Age (EBA) settlement Fidvár near Vráble (Slovakia). Large-scale geomagnetic prospection revealed detailed architectural remains of a fortified settlement. Other structures such as an earthwork of the linear pottery culture and at least two Roman march camps were found too. An Auger programme provided sediment samples of different depths, A) from an EBA house and the outer fortification ditch, B) from a potential metal workshop area as indicated by surface finds, and C) from an area located in the settlement's centre. The samples were analysed by a portable X-ray fluorescence (pXRF) spectrometer in order to investigate the vertical and horizontal distribution of chemical signatures. The comparison of geophysical data and three-dimensional chemical patterns gives us the opportunity to determine the human impact and to reconstruct activity patterns. The potentials and limits in the application of pXRF in archaeological soil chemical surveys are evaluated by systematic comparisons with high resolution laboratory measurements, including atomic absorption spectrometry (AAS) and inductively coupled plasma optical emission spectrometry (ICP-OES). The pXRF analyses can be reproduced well and show a good accuracy. Whilst (p)XRF analyses reflect the total composition of archaeological soil samples, the results of the AAS and ICP-OES analyses are fundamentally influenced by the acid digestion or extraction methods used. The pXRF analyses of the Vráble soils showed typical patterns of human occupation. For example, there are strong positive correlations between phosphorous, strontium and calcium. Phosphorous shows an enrichment in pathways and the fortification ditch. It is less strongly enriched within the sediments of house structures. Similar results apply to calcium and strontium distribution. But compared to the respective concentrations in sediment samples from the ditch they show a considerably higher variation in samples associated with house structures; that is, individual samples of sediments from house structures contained high concentrations of both, calcium and strontium. The deposits of an area that according to surface finds was thought to represent a potential metal workshop did not show indicative chemical signatures. Targeted excavations confirmed the absence of such as workshop. Finally it was shown that the refill history of the innermost fortification ditch (sample area D) and the overall cultural occupation sequence at the site correlate strongly with the chemical signatures of the respective ditch profile. The systematic variation of key elements along the profile opens up an entirely new perspective for interpreting the site's history. Overall, the study shows the great potential of pXRF as valuable part of an archaeological survey toolkit.     

Biological mineral content in Iberian skeletal cremains for control of diagenetic factors employing multivariate statistics

The aim of this study was to define a strategy for a correct selection of bone samples by employing inductively coupled plasma optical emission spectroscopy (ICP-OES) for reconstructing the biological mineral content in bones through the determination of major elements, trace elements and Rare Earth Elements (REE, lanthanides) in skeletal cremains of ancient Iberians (III–II B.C), discovered in the Necropolis of Corral de Saus (Moixent, Valencia) between 1972 and 1979. The biological mineral content was determined taking into account diagenetic factors. A control method for a better reading of results was applied. To explore large geochemical datasets and to reduce the number of variables, Principal Component Analysis (PCA) was used, thus, providing a deeper insight into the structure of the variance of the dataset. PCA shows that the elemental profiles of bone and soil samples are clearly different. Bone samples obtained from the outer bone layer were shown to have a different elemental composition; more similar to soil samples than samples of the inner bone layer. PCA scores and loadings plots were preferred to dendrograms obtained using Cluster Analysis, due to the limits of the latter one to appreciate the spatial ordering of samples. Partial least squares discriminant analysis (PLS-DA), a frequently used supervised classification method, was applied to differentiate between degradation states of bone samples. PLS-DA results obtained in this study confirmed that changes derived from different burning conditions were associated with transformations in the mineral part of the bones. Accordingly, carbonized bones can be differentiated from cremated bones. Class assignment of bone samples with uncertain thermal conditions in dependence on their elemental composition has shown to be feasible. Consequently, for biochemical-archaeological studies the analysis and statistical classification of carbonized and cremated archaeological bones, as well as those exposed to unknown thermal conditions together with experiments in modern bones, are recommended.     

Identifying domestic functional areas. Chemical analysis of floor sediments at the Classical-Hellenistic settlement at Düzen Tepe (SW Turkey)

For over a decade, multi-element chemical analysis of floor sediments in archaeological contexts has been a tool to identify and interpret anthropogenic chemical residues and activities. For the current study, a multi-element chemical analysis was applied to floor samples from a Classical-Hellenistic courtyard building at Düzen Tepe (SW Turkey). Among a series of 19 elements analyzed, K, Mg, Fe, P and Sr are thought to directly reflect anthropogenic chemical residues. The elements Cr, Mg, Ni, Pb and Ti are considered to reflect the geological background of the site, yet their contents seem to vary over different chemical residue zones, making them a suitable tool for delineating activity areas. Overall, the sampling and analysis techniques applied at Düzen Tepe – mild acid sample extraction and ICP-OES analysis – have proven to be fit for this kind of study. The analyses allow human activity zones within the study area to be identified and interpreted and deliver insights into the archaeological contexts that could not be obtained by archaeological research alone.