Archaeometric Data Research Articles

Variable Selection in Compositional Data Analysis Using Pairwise Logratios

In the approach to compositional data analysis originated by John Aitchison, a set of linearly independent logratios (i.e., ratios of compositional parts, logarithmically transformed) explains all the variability in a compositional data set. Such a set of ratios can be represented by an acyclic connected graph of all the parts, with edges one less than the number of parts. There are many such candidate sets of ratios, each of which explains 100% of the compositional logratio variance. A simple choice consists in using additive logratios, and it is demonstrated how to identify one set that can serve as a substitute for the original data set in the sense of best approximating the essential multivariate structure. When all pairwise ratios of parts are candidates for selection, a smaller set of ratios can be determined by automatic selection, but preferably assisted by expert knowledge, which explains as much variability as required to reveal the underlying structure of the data. Conventional univariate statistical summary measures as well as multivariate methods can be applied to these ratios. Such a selection of a small set of ratios also implies the choice of a subset of parts, that is, a subcomposition, which explains a maximum percentage of variance. This approach of ratio selection, designed to simplify the task of the practitioner, is illustrated on an archaeometric data set as well as three further data sets in an “Appendix”. Comparisons are also made with existing proposals for selecting variables in compositional data analysis.

Efficiency and quality raising in preventive archaeology: work in progress of the project ARCHEO 3.0

Preventive archaeology aims at assessing the archaeological interest of a given area, as well as discovering, interpreting, documenting, and protecting archaeological remains that might otherwise be destroyed by land development works. On request of private stakeholders or institutional bodies, archaeologists intervene on a given construction yard (of infrastructure or urbanisation works) in order to investigate the possible archaeological significance of zones subjected to excavation works. In many cases archaeological assays are carried out, which are associated with thorough stratigraphic documentations and definition of the final preservation conditions. The latter can involve suitable re-burying or musealization of some of the archaeological remains recovered. During these activities, the construction works are slowed down or completely interrupted up until the conclusion of the mentioned archaeological research, which can generate possible delays with respect to the planned time schedule and increase of the costs. Improvements are needed in order to minimise the duration of the archaeological assessment and, simultaneously, to guarantee quality standards even higher than tose stated by the competent superintendences. Within this framework, the project ARCHEO 3.0 “Integration of Key Enabling Technologies for rising the efficiency and quality of preventive archaeological excavations” (co-funded by Tuscany Region, POR-CReO 2014-2020) aims at speeding up the archaeological excavation and at improving its documentation. It foresees the development of a set of characterisation tools, their integration and validation in archaeological yards. Thanks to ICT solution such a multidisciplinary integration will be made possible by a dedicated web-based platform that will allow to manage 2D and 3D photogrammetry along with the data provided by electromagnetic, and acoustic sensors. The project aim at promoting a substantial step ahead of the preventive archaeology in order to overcome the traditional empiric approach. In this respect, data exchange and the ICT solutions for direct collection of information on archaeological evidences represent the major challenge. Here, we preliminarily focus on the general features of management protocols of the archaeometrical data, as well as on their suitable integration within the operative phases of the archaeological excavation.

A Sensory Update to the Cha\xeene Op\xe9ratoire in Order to Study Skill: Perceptive Categories for Copper-Compositions in Archaeometallurgy

This paper introduces the methodology of perceptive categories through which an empirical analysis of skill is achievable, taking European Bronze Age metalworking as a case study. Based on scientific data provided by the material sciences, in this case compositional and metallographic analyses of Late Copper Age and Early Bronze Age axes, the thresholds to categorise and interpret these data, and organise them in a chaîne opératoire, are centred on the human senses—and thus on metalworking as a craft. This is a pragmatic approach that appreciates scientific measurements of metal objects as essential empirical evidence whilst recognising that a considerable share of these archaeometric data are inapt or too detailed for an understanding of skill. This empirical approach towards skill is relevant to our knowledge of the role of crafts and materials in the past. After all, skill is a fundamental asset for the production of material culture, and a distinct human-material relationship characterised by an intimate form of material engagement.

Neural Networks (SOM) Applied to INAA Data of Chemical Elements in Archaeological Ceramics from Central Amazon

ABSTRACTArtificial neural networks represent an alternative to traditional multivariate techniques, such as principal component and discriminant analysis, which rely on hypotheses regarding the normal distribution of the data and homoscedasticity. They also may be a powerful tool for multivariate modeling of systems that do not present linear correlation between variables, as well as to visualize high-dimensional data in bi- or trivariate structures. One special kind of neural network of interest in archaeometric studies is the Self-Organizing Map (SOM). SOMs can be distinguished from other neural networks for preserving the topological features of the original multivariate space. In this study, the self-organizing maps were applied to concentration data of chemical elements measured in archaeological ceramics from Central Amazon using instrumental neutron activation analysis (INAA). The main objective was testing the chemical patterns previously identified using cluster and principal component analysis, forming groups of ceramics according the multivariate chemical composition. It was verified by statistical tests that the chemical elemental data was not normally distributed and did not present homogeneity of covariance matrices for different groups, as requested by principal component analysis and other multivariate techniques. The maps obtained were consistent with the patterns identified by cluster and principal component analysis, forming two chemical groups of pottery shards for each archaeological site tested. Finally, it was verified the potential of SOMs for testing if failures in underlying hypotheses of traditional multivariate techniques might be critically influencing the results and subsequent archaeological interpretation of archaeometric data.

Copper production landscapes of the South Caucasus

Studies of metal production frequently show a correlation between scale and organizational complexity. The remarkably rich landscapes of metal-producing sites of late 2nd-early 1st millennium BC Colchis provide an unprecedented opportunity to reexamine this apparent correlation. Investigations of copper smelting sites show that industries with a large aggregate output can be the result of numerous small groups of metalworkers acting independently. Spatial data on site distributions, estimates of productive output, and archaeometric data on ore procurement patterns were integrated to reconstruct the organization of production. Judicious use of a portable X-ray fluorescence spectrometer (pXRF) showed that not only were smelting sites highly dispersed, but also that metalworkers at different sites were using ores from geologically distinct deposits. This innovative approach helped to reconstruct the organization of production in a distinctive metal production landscape, bridging an enduring divide between landscape-scale and microscopic investigations of craft production.

The circulation of Early Neolithic pottery in the Mediterranean: A synthesis of new archaeometric data from the Impressed Ware culture of Liguria (north-west Italy)

The use of ceramic sourcing to study the scale of human interaction has revealed new perspectives on Early Neolithic voyaging in the Ligurian Sea (northern Italy). We have documented, through archaeometric analyses and in particular optical microscopy of 50 thin sections, the discovery of imported vessels at important prehistoric sites of the Impressed Ware culture of western Liguria. The imported fabrics are characterised by inclusions of gneisses, ophiolites or alkaline-potassic volcanic rocks, which are incompatible with local formations. The sources of these imports could be a few geological areas of the Tyrrhenian coast between central Liguria, Corsica and Lazio. The results of this research demonstrate that a very early maritime circulation of pottery began in the central Mediterranean, with the introduction of ceramic pyrotechnology at the beginning of the Neolithic period (c. 6000BCE). The provenanced areas for the imported vessels suggest that the route of human colonisation of the Ligurian-Provençal arch could have been from the south-east, probably favoured by the north-west direction of the surface marine currents. The stylistic similarities (in vessel shapes and decorative motifs) observed in the pottery production and other aspects of the material culture from the Impressed Ware sites of the north and central Tyrrhenian coast are thus explained as the result of an intensive contact network that existed between the populations living along the coast of the Mediterranean, which were trading and exchanging several commodities overseas, presumably including obsidian and greenstones but also, perhaps, perishable substances contained in vessels.

The use of different amber sources in Italy during the Bronze Age: new archaeometric data

The production of amber ornaments occurred in Italy during the Eneolithic (E)–Early Bronze Age (EBA), although very few beads from the Italian peninsula have been found and analysed. The number of data available for provenience study of Bronze Age ambers is larger, but still a precise picture of when and to what extent the local sources of amber were exploited is lacking. In the present work, 22 amber finds from six Sicilian sites have been studied and analysed by infrared spectroscopy, in particular with DRIFT (diffuse reflectance infrared Fourier transformed) analyses. The amber samples are dated between the Eneolithic and the Final Bronze Age–Early Iron Age and are from the collections of the P. Orsi Museum, in Syracuse (Sicily). The data show that only simetite was used in South Italy in the Late Eneolithic (LE)–EBA. In the Bronze Age, the exploitation of simetite shows different intensity in different chronological phases. The results are discussed in comparison with the information available for coeval European ambers.

P.1.j.012 - Effects of chronic memantine treatment on okadaic acid induced memory impairment and changes in neurotransmitter activity in the septo-hippocampal system

Studies of metal production frequently show a correlation between scale and organizational complexity. The remarkably rich landscapes of metal-producing sites of late 2nd-early 1st millennium BC Colchis provide an unprecedented opportunity to reexamine this apparent correlation. Investigations of copper smelting sites show that industries with a large aggregate output can be the result of numerous small groups of metalworkers acting independently. Spatial data on site distributions, estimates of productive output, and archaeometric data on ore procurement patterns were integrated to reconstruct the organization of production. Judicious use of a portable X-ray fluorescence spectrometer (pXRF) showed that not only were smelting sites highly dispersed, but also that metalworkers at different sites were using ores from geologically distinct deposits. This innovative approach helped to reconstruct the organization of production in a distinctive metal production landscape, bridging an enduring divide between landscape-scale and microscopic investigations of craft production.

Box-Cox transformation on dataset from compositional studies of archaeological potteries

In archaeometric data set it was verified by statistical tests that some variables almost never follow a multivariate normal distribution using logarithmic transformation or other. This work presents a multivariate Box-Cox transformation for Mardia´s and Royton´s tests for a data set of fifty ceramic fragments from archaeological site Justino, Xingo, Brazil, and one clay sample collected near of the site. The samples were analyzed by instrumental neutron activation analysis, INAA. The study was made using companion to applied regression package from R software and was tested by Hotelling’s T 2 statistics.

Composition and microstructure of maiolica from the museum of ceramics in Ascoli Piceno (Italy): evidences by electron microscopy and microanalysis

The present work focuses on majolica objects from the collection of the museum of ceramic in Ascoli Piceno (Italy). The scientific investigation was performed on fragments detached from seven maiolicas attributed to the Castelli production (Abruzzi region) and one majolica from the Ascoli Piceno production (Marche region). The Castelli artifacts (late sixteenth–early eighteenth century) belong to the decorated style known as “compendiario.” The piece from Ascoli Piceno recalls the decoration style of the other considered objects and is attributable to the “Paci” manufacture (first half of the nineteenth century). The selected objects were investigated by fiber optics reflectance spectroscopy, micro-X-ray fluorescence spectroscopy and scanning electron microscopy coupled with electron-dispersive X-ray spectrometry. The ceramic bodies of all objects are calcareous, whereas the glazes are lead-alkali type opacified by tin dioxide. Blue and purplish-red decorations were obtained by cobalt and manganese compounds dissolved in the glaze, respectively. Yellow and orange decorations were obtained by particles of lead antimonate and hematite. Finally, black decorations were obtained using compounds rich in manganese and iron. The study contributes to knowledge on the production of Castelli ceramics and presents first archaeometric data on the maiolica production from Ascoli Piceno. The scientific examination highlights continuity with the Renaissance production, and the joint contribution of the three analytical techniques suggests distinctive features among different productions, thus integrating and refining the information obtained by the art-historical study.

Początki kultury pucharów lejkowatych na Niżu Polskim

In the article, the author discusses and accepts the need to rejuvenate the chronology of the beginnings of the Funnel Beaker culture in the Polish Plain which should be then dated to about 4200/4100 years BC. While accepting such an approach, the author presents also some of its consequences – e.g. multi-stylistic of pottery and variability of environments inhabited by the earliest Funnel Beaker communities. The article also presents some suggestions concerning the participation of huntergatherers and early agrarian groups in the shaping of this culture in the Polish lowlands. It also raises some questions, which, under the new chronological circumstances, await further archaeometric data and proper discussion.

Innovation and Collapse: Bucket-Shaped Pottery and Metalwork in the Terminal Migration Period

In this article we focus on the third and final production phase for the distinct and atypical bucket-shaped pottery in south-west Norway, during the last decades of the Migration Period in the 6th century ad. The culmination of a unique progression that probably extended nearly two centuries, this phase is characterized by high-quality ceramics and metal handcraft. The two craft types had broadly similar trajectories, but eventually it seems only potting disappeared. We explore specific links between production modes for bucket-shaped pots, contemporary ceramic types and high-quality metal and glass objects. The approach combines recently analysed archaeometric data with sophisticated ethnographic understanding of the dynamics of paste recipes among potters, while also reviving and refining the astute conclusion by Haakon Shetelig (1905) dating back more than a century. We argue that knowledge transmission for high-quality bucket-shaped potting emanated from certain contexts which included artisans working in gold, silver and bronze. These workshops functioned as creative nodes, developing most of the new craft techniques in the 6th century. Consequently, the peak period and eventual demise of terminal Migration Period high-quality bucket-shaped potting cannot be viewed in isolation from the production modes of Style I animal art.

Variable selection study using Procrustes analysis

Several analytical techniques are often used in archaeometric studies, and when used in combination, these techniques can be used to assess 30 or more elements. Multivariate statistical methods are frequently used to interpret archaeometric data, but their applications can be problematic or difficult to interpret due to the large number of variables. In general, the analyst first measures several variables, many of which may be found to be uninformative, this is naturally very time consuming and expensive. In subsequent studies the analyst may wish to measure fewer variables while attempting to minimize the loss of essential information. Such multidimensional data sets must be closely examined to draw useful information. This paper aims to describe and illustrate a stopping rule for the identification of redundant variables, and the selection of variables subsets, preserving multivariate data structure using Procrustes analysis, selecting those variables that are in some senses adequate for discrimination purposes. We provide an illustrative example of the procedure using a data set of 40 samples in which were determined the concentration of As, Ce, Cr, Eu, Fe, Hf, La, Na, Nd, Sc, Sm, Th, and U obtained via instrumental neutron activation analysis (INAA) on archaeological ceramic samples. The results showed that for this data set, only eight variables (As, Cr, Fe, Hf, La, Nd, Sm, and Th) are required to interpret the data without substantial loss information.

The glass of the “Casa delle Bestie Ferite”: a first systematic archaeometric study on Late Roman vessels from Aquileia

Aquileia (Italy) is one of the largest Roman cities so far excavated, and is on the UNESCO World Heritage List. The significant amounts of glass found in the site have suggested to many researchers that Aquileia played a central role in glass production and trade in ancient times, although only very few archaeometric data have been obtained so far. In this context, an archaeological and archaeometric study was conducted on 62 unintentionally coloured samples of Late Roman glass (late 3rd–6th centuries AD) from the excavation of the Casa delle Bestie Ferite (“House of the Wounded Animals”). Results indicate the importance of Aquileia in the glass trade. Bulk chemistry (EPMA and XRF data) evidences a compositional transition with respect to Early Roman glass (1st–3rd centuries AD), indicating changes in raw materials for glass-making. In particular, the chemical data show the close similarity between Aquileia glass and some of the main compositional groups widespread in the Mediterranean from the 4th century onwards (HIMT, Levantine I, Série 3.2), suggesting their probable common origin in the Eastern Mediterranean. This evidence suggests there was no primary glass production in Aquileia, as presumed in the past by some authors. No relationships between chemical composition, type, chronology or production technique have been observed, although the possible connection between HIMT-type glass and low-quality objects such as bottles cannot be completely excluded and must be better investigated in future research.

Glass from the Archaeological Museum of Adria (North-East Italy): new insights into Early Roman production technologies

In the present study, the first archaeometric data on an ample selection of intentionally coloured (or decoloured) Early Roman glass (1st–2nd centuries AD) from the Archaeological Museum of Adria (Rovigo, Italy) are reported. The analysed samples are 61 in total, both transparent and opaque, and were characterised from the textural (SEM-EDS), mineralogical (XRPD) and chemical (XRF, EPMA, LA-ICP-MS) points of view. This combined approach allowed us to identify the raw materials and production technologies employed in the manufacture of glassware. Results for the transparent samples show that they are all silica-soda-lime glasses. Most of them, independently of colour, have compositions close to those of typical Roman glass, produced with natron as flux. No relationships were identified among chemical compositions, types or production techniques, but a dependence on bulk composition was identified for some particular colours, revealing the careful and intentional selection of raw materials. This is the case of Sb-colourless glass, produced with sand of high purity, a group of intensely coloured objects, mainly emerald green and black, produced with soda ash as flux, and some blue examples produced with various sources of sand or soda ash as flux. Two main types of opacifiers were identified for the opaque samples: calcium antimonate for white, mauve and blue glasses, and lead antimonate for the yellow ones; in one case, a yellow lead-tin antimonate was also identified. As regards the opaque glasses, most of the samples opacified with calcium antimonate are silica-soda-lime in composition, similar to the typical Roman glass. Instead, samples opacified with lead and/or lead-tin antimonates are lead glasses, suggesting different production technologies.

Pre-Roman glass from Mozia (Sicily-Italy): the first archaeometrical data

This study present the results of an archaeometrical investigation performed on a series of opaque pre-Roman glass (vessels and ornaments) dated from the 6th to 4th century BC coming from Sicily. Sixteen core formed vessels, twelve beads, three pendants and one spindle-whorl recovered in the Phoenician-Punic sites of Mozia and Birgi were analysed thought a micro destructive approach. The complete chemical analyses and X-Ray diffraction analyses were performed on small fragments of glass. The aims of this work are: 1) to obtain a chemical characterization of these samples in order to understand the raw materials employed for their production; 2) to obtain information regarding the opacifying phases dispersed in the glass; 3) to make a comparison with the results recently obtained on coeval and similar finds recovered in other cultural context, in particular in Northern Italian Etruscan contexts in order to understand whether they could belong to the same Greek-Eastern production.The chemical data of these samples confirm they are silica soda lime glass produced with natron. The opaque decorations of the samples were done by using Sb based opacifiers. The major and minor analyses of the majority of the samples seem to suggest a common origin with the coeval material found in Northern Italian context. On the contrary, for some artifacts, in particular the pendants, a Phoenician-Punic origin is supposed.

Archaeometry meets archaeozoology: Viking Haithabu and medieval Schleswig reconsidered

The two archaeofaunal assemblages from Haithabu (Viking period) and Schleswig (early Middle Age) belong to the largest such bone complexes ever recovered in Northern Europe. More than 800,000 animal bones were recovered from both sites in the course of the last three decades and investigated by traditional archaeozoological methods. More recently and independently from the latter, stable isotopic ratios of the light elements carbon, nitrogen, and oxygen were analyzed on a total of 440 animal bone finds representing 67 vertebrate species from both sites producing a data set comprising 1,760 individual isotopic ratios. In addition, stable strontium isotopic ratios were obtained from 68 animal teeth and bones of four species. In this paper, an attempt is made to synthesize archaeozoological and archaeometrical data on a larger scale. By becoming familiar with the specific potential of each method, we raise questions concerning not only palaeobiodiversity and palaeoecology of fish and birds in the area, trophic webs, and prey/predator relationships, but also human meat-provisioning, import of animals and animal products, and the reconstruction of hunting areas. This transdisciplinary approach led to an improvement in the quality of our interpretations and the validation of previously confirmed and/or rejected assumptions. It is still too early to expect answers to all these questions, but we are convinced that, in attempting to do so, the potential of coordinating such methods for future research will become evident, and we therefore strongly recommend an intensification of archaeometric analyses of archaeofaunal assemblages.

GAMBLING WITH ETRUSCAN DICE: A TALE OF NUMBERS AND LETTERS

The graphical and linguistic interpretation of the first six Etruscan numerals has long been confronted with the ambiguous assignment of the words huth and sa to either 4 or 6. Here, we show how the systematic combinatorial analysis of the numerals appearing on ancient southern Etrurian dice dated from the eighth to the third centuries bc, together with the careful comparison of the results with the only two existing dice carrying the alphabetical translations of the numerals conserved at the Bibliothèque Nationale de France, Paris, finally allows unambiguous mathematical resolution of the linguistic riddle, allowing the firm attribution of the numeral 6 to the graphical value huth and 4 to sa. Combinatorial analysis of the numerals distribution on the six faces of the die shows that only two of the 15 possible numerical combinations were actually in use in southern Etruria, and that during the fifth century bc there was a marked shift from the typical (1–2, 3–4, 5–6) combination used in the early seventh‐ to fifth‐century bc dice to the (1–6, 2–5, 3–4) combination used at later times and still largely adopted today. The largest body of archaeometric data on dice specimens from Etruria is presented, based on macroscopic examination, X‐ray diffraction, DRIFT spectroscopy and density measurements.

Archaeometric study on terra sigillata from Cales (Italy)

Mineralogical and petrographical studies on 23 ancient pottery fragments of terra sigillata from ancient Cales (today Calvi Risorta, Caserta) are here discussed. Stamps on pottery surfaces assigned the fragments to Cales and other Italian workshops acting in Arezzo and Northern Italy area between 1 st century B.C.-1 st century A.D., other stamped fragments have an uncertain provenance. The mineralogical and petrographical features of pastes have been detected using optical microscopy, X-ray diffraction, X-ray fluorescence, and DTA-DTG analyses. The geochemical comparisons among ceramics, production indicators of Calenian pottery (Black Glazed pottery spacers) and local clayey raw materials allowed to distinguish locally produced potsherds from imported ones. Moreover, the whole archaeological and archaeometric data set allowed to draw main technological aspects of a fine ware production much used on rich roman tables.

Sobre el origen y la cronología del trípode de varillas de La Clota (Calaceite, Teruel): nuevos datos arqueométricos

New archaeometric data on the fragments of the rod tripod of Cypriote type found at the site of La Clota (Calaceite) enable the reassessment of this artefact from a new perspective. The most important results emerging from this work are related to the method of manufacture by lost-wax casting, to the fact that it is a ternary alloy and, above all, the fact that the lead used came from the Iberian Peninsula. These new data, together with those already known about the influence of the Cypriot-Levantineinfluenced bronze-work in the central and western Mediterranean, indicate that the piece is of local manufacture and lead to a discussion of this type of object as a whole.