RETENTION OF PHOSPHATE IN BURIED CERAMICS: AN ELECTRON MICROBEAM APPROACH

Elevated concentrations of P₂O₅ of 2–12 wt% absolute were observed in the matrices of a small group of ceramics with the electron microprobe. P₂O₅, CaO and FeO^t are enriched towards the surfaces in some cases and elemental correlations suggest precipitation of a crystalline calcium phosphate with a stoichiometry close to CaO · P₂O₅. Scanning electron microscopy with X-ray mapping showed P₂O₅ to be dispersed in the ceramic matrix on a very fine scale, while X-ray diffraction detected no crystalline phosphate. Parallels are drawn with the precipitation of phosphate in the surfaces of weathered glass. It is concluded that the amorphous phases produced on firing behave as chemically active substrates which facilitate the adsorption or precipitation of very fine grained calcium phosphate from the burial environment.     

The geochemical diversity of neogene clay deposits in Crete and its implications for provenance studies of Minoan pottery*

The determination of provenance probably forms the primary role of geochemical analyses in archaeological ceramic studies. In what has comprised a successful field of study, the ultimate basis for such research has been the comparison of pottery compositions with the geochemical diversity displayed by clay deposits within a given study area. Although such studies are now common, the understanding of chemical and mineralogical variability in ceramic raw materials has been somewhat neglected, with the dominance of assumptions rather than the actual analysis of clays. In this paper, a study is presented of Neogene clays in Crete (Greece), a clay type commonly used in ancient and modern pottery production. Sixty‐one samples were taken from 28 locations in the central and eastern parts of the island, to reveal both intra‐ and inter‐deposit variability. In one deposit chosen for multiple sampling, the 14 samples display great variability in the alkali elements, Fe and Co, and to a lesser extent in the REEs. Many of the geographically separate deposits differ from each other in chemical composition, with Eastern Cretan deposits showing higher REE concentrations and higher Th/Sc ratios, whereas Central Cretan deposits of younger geological stages are characterized by a lower Th/U ratio. Mineralogical analysis by XRD is used to explain aspects of the geochemical variability of the clays.     

A study of the glazing techniques and provenances of Tang sancai glazes using elemental and lead isotope analyses

This study discusses the elemental compositions and lead isotope ratios of Tang sancai glazes unearthed from the Huangpu kiln, Huangye kiln and two Tang sancai tomb sites. The various glazes feature distinct lead isotope ratios and trace element characteristics, which can be interpreted as evidence for the use of different lead ore deposits and siliceous raw materials in the glazes. This is a strong indication that lead isotopes combined with trace element analysis could be used as a viable approach for identifying the provenance of Tang sancai of unknown origin by linking them to kiln sites, This provenance technique could be significant in the interpretation of ancient ceramic trade and communication patterns. In this study, the provenance of several Tang sancai glazes of uncertain origin were determined using this method: some Tang sancai wares unearthed in Xi'an City were produced in the kiln near Luoyang City and then traded to Xi'an City, providing an idea of ancient Tang sancai ceramic trade routes.     

Linear Enamel Hypoplasia and Age‐at‐Death at Medieval (11th–16th Centuries) St. Gregory's Priory and Cemetery,Canterbury, UK

Linear enamel hypoplasia (LEH) is a macroscopically detectable band‐like dental defect, which represents localized decrease in enamel thickness caused by some form of disruption to a child's health. Such dental deformations are utilized in osteoarchaeological research as permanent markers of childhood physiological stress and have been extensively studied in numerous ancient human populations. However, currently there is no such data for medieval populations from Canterbury, UK. Here, LEH is examined in the context of age‐at‐death in human burials from the medieval St. Gregory's Priory and adjacent cemetery (11^th–16^th centuries), Canterbury, UK. The cemetery and Priory burials represented lower (n = 30) and higher status (n = 19) social groups, respectively. Linear enamel hypoplastic defects were counted on mandibular and maxillary anterior permanent teeth (n = 374). The age and sex of each skeleton were estimated using standard methods. Differences in LEH counts, age‐at‐death, and LEH formation ages were sought between the two social groups. Results indicate significantly greater frequencies of LEH in the Cemetery (mean = 17.6) compared to the Priory (mean = 7.9; t = −3.03, df = 46, p = 0.002). Adult age‐at‐death was also significantly lower in the Cemetery (mean = 39.8 years) compared to the Priory burials (mean = 44.1 years; t = 2.275, df = 47, p = 0.013). Hypoplasia formation ages differed significantly between the Priory (mean = 2.49 years) and Cemetery (mean = 3.22 years; t = 2.076; df = 47; p = 0.034) individuals. Results indicate that childhood stress may reflect adult mortality in this sample, and that the wellbeing of individuals from diverse social backgrounds can be successfully assessed using LEH analyses. Results are discussed in terms of the multifactorial etiology of LEH, as well as weaning‐related LEH formation. Copyright © 2012 John Wiley & Sons, Ltd.     

A NEW DATING METHOD FOR HIGH‐CALCIUM ARCHAEOLOGICAL GLASSES BASED UPON SURFACE‐WATER DIFFUSION: PRELIMINARY CALIBRATIONS AND PROCEDURES*

The first European settlers came to North America in the early 17th century using glass in the form of containers and decorative objects. Thus, glass is a horizon marker for all historic period settlements and a potential source of chronometric dates at archaeological sites belonging to the historic period in the Americas. We have developed a new absolute dating method based upon water diffusion into the surface of manufactured glasses that predicts diffusion coefficients based upon variation in glass chemical constituents. Low‐temperature (< 190°C) hydration experiments have been performed on a set of five high‐calcium (21.7–28.3%) glasses that were used to manufacture wine bottles from the 17th?19th centuries. Infrared spectroscopy and secondary ion mass spectrometry was used to model the water diffusion/alkali exchange process. The ability of the model to accurately predict archaeological ages was evaluated with artefacts recovered from ceramic‐dated contexts at Thomas Jefferson's plantation known as Monticello.     

FTIR AND SOLID‐STATE 13C CP/MAS NMR SPECTROSCOPY OF CHARRED AND NON‐CHARRED SOLID ORGANIC RESIDUES PRESERVED IN ROMAN IRON AGE VESSELS FROM THE NETHERLANDS*

In this study, solid‐state ¹³C magnetic resonance spectroscopy using cross‐polarization combined with high‐powered proton decoupling and magic‐angle sample spinning and Fourier transform infrared spectroscopy using a diamond anvil cell, are employed to give information about the organic functional groups present in charred and non‐charred solid organic residues and to give an insight into the degree of condensation of the chars. Residues were preserved in ceramic vessels recovered from the indigenous settlement of Uitgeest–Groot Dorregeest, dating back to the Roman period. In addition, the application of these solid‐state techniques is used for verification of earlier results obtained in analytical pyrolysis studies and to clarify the relationship between the already thermally degraded charred residues and the controlled heating fragmentation taking place during analytical pyrolysis and direct temperature‐resolved mass spectrometry.     

The production and technology of glazed ceramics from the middle ages,found in the saepinum territory (Italy): a multimethodic approach*

A collection of ceramics from the Middle Ages found in Altilia and Terravecchia (the Saepinum area, Campobasso, Italy) were characterized by using different mineralogical analyses to investigate their provenance and production techniques. The body ceramic was investigated using Rietveld phase analysis of X‐ray powder diffraction patterns, X‐ray fluorescence spectrometry and scanning electron microscopy. The chemical compositions of the coatings were measured by scanning electron microscopy and their mineralogical compositions were determined using a particular technique of X‐ray small‐angle scattering (SAS) optimized for studies of thin films. Moreover, the material used for decoration was studied using micro‐Raman spectroscopy. The archaeometric results confirmed the distinction into two different ceramic classes, already individuated from archaeological analysis: the Altilia objects belong to the protomajolica class, whereas the objects from Terravecchia are RMR (ramina‐manganese‐red) ceramics. A comparison between the chemical and mineralogical compositions of good‐quality ceramic objects and those of waste products indicated local production of the ceramics. A sharp distinction was found in the chemical composition of the coatings: the Altilia products have tin‐opacified lead glazes, while the Terravecchia ones have transparent high‐lead glazes. Among the Altilia products, the unsuccessful process that produced a large quantity of discarded materials was attributed to the high lead content of the glazes. In fact, the principal advantage of the high lead content was to make the preparation and application of the glaze suspension easier, but the risk of reduction of lead oxide to metallic lead was greatly increased. Using micro‐Raman spectroscopy, the following minerals were identified as pigments: pyrolusite for the dark colour, malachite for green, lepidocrocite for yellow and hematite for red.     

A non-invasive study of Roman Age mosaic glass tesserae by means of Raman spectroscopy

Ancient mosaic tesserae are a range of materials of very varied and complex nature, including pottery, stone and glass. Raman spectroscopy is a powerful tool for the analysis of all these kinds of materials. In the particular case of glasses, this technique can be used both for a study of surface weathering and for the characterization of bulk structure, but it has not yet been extensively used for the characterization of mosaic glass tesserae. We carried out Raman analyses on a set of Roman and Late Antiquity period mosaic glass samples, which allowed a good characterization of both the glass matrix and the crystalline inclusions. All the samples show the typical Raman signatures of soda-lime-silicate glasses. Several crystalline phases were also identified, being relics of raw materials used during the glass manufacturing process, such as quartz and feldspars, or linked to the glass color/opacification, such as bindheimite and cuprite. The analyses also led to the identification in some blue, turquoise and green tesserae of calcium antimonate, whose Raman signature has only recently been recognized in the scientific literature on mosaic glasses. Some emphasis is given to the analysis of red lead-containing tesserae, colored with Cu⁺ ions or even Cu⁰ (or Au⁰) metal nanoparticles. Samples with peculiar compositions, as well as “modern” (and restoration) samples, could quite easily be distinguished from the ancient ones by their Raman spectra.     

Hardwood ash nixtamalization may lead to false negatives for the presence of maize by depleting bulk δC in carbonized residues

Among the multiple proxies for detecting maize in precontact economies is the use of δ¹³C analysis of carbonized residues from ceramic cooking vessels. Although maize horticulture was widely established in Eastern North America (ENA) by A.D. 1000, there are carbonized residues from ceramic assemblages after this date that lack the elevated δ¹³C values indicative of the presence of maize. This may be due to the true absence of maize, or other factors including the masking of maize. Prior experimental research by Hart et al. demonstrated that the addition of C₃ plants or consumers to two part mixes with maize can mask maize presence even when maize is the dominant ingredient. Here we investigate the effect of alkali processing of maize (nixtamalization) on δ¹³C using the widespread ENA process of boiling maize kernels with wood ash, a C₃ product, to create hominy. Our experiments test whether or not the process of hardwood ash nixtamalization can mask the presence of maize in adhering carbonized residues by depleting δ¹³C values, and whether there is a reciprocal δ¹³C enrichment effect on the hardwood ash employed in nixtamalization. Overall, there is substantial δ¹³C depletion of residues when maize is cooked with hardwood ash, and hardwood ash cooked with maize shows the reciprocal enrichment. Therefore, the depleted values after the adoption of maize may be false negatives due to the nixtamalization process.     

AN 8500‐YEAR‐OLD BLADDER STONE FROM UZZO CAVE (TRAPANI): FOURIER TRANSFORM–INFRARED SPECTROSCOPY ANALYSIS*

A calcium carbonate (calcite) bladder calculus was found in the pelvis of an adult female buried in a Mesolithic cave‐tomb on the coast of Sicily; it was dated by ¹⁴ C to around 6500 bc . Its chemical composition, which was not known before, was determined by means of Fourier transform–infared microspectroscopy (FT–IR–M) using the high‐pressure diamond cell, a device that makes it possible to analyse a small amount of the sample (1–2 µg). In this way, the analysis of all the laminations of the calculus was performed without destroying the sample. Although calcite was the main component, carbonate apatite was also detected in the nucleus and in a more external layer.     

δ18O Analyses of the Humpbacked Conch (Gibberulus gibberulus): Evaluating a Proxy for Reconstructing Sea-Surface Temperature at Chelechol ra Orrak,Palau

ABSTRACT

In Palau, Micronesia, marine resources, particularly shellfish, played a vital role in human subsistence for millennia. Despite the vast array of molluscan species in archaeological assemblages, there is a dearth of data on nearshore palaeoecology or prehistoric shellfish foraging practices. In this study, we analysed stable oxygen isotopes (δ¹⁸O) values present in the calcium carbonate shell of Gibberulus gibberulus from the Chelechol ra Orrak archaeological site to reconstruct average nearshore sea-surface temperatures (SST) from approximately 1500–1100 cal BP. Modern shellfish samples and environmental data were collected from intertidal zones near the site and x-ray diffraction (XRD) was employed to identify the biomineralogical composition of G. gibberulus. These steps provide necessary information for the selection of the proper oxygen isotope-to-SST conversion formula. The selected formula was applied to δ¹⁸O samples from archaeological shells to reconstruct prehistoric SST averages. The results of this proxy validation study verify that G. gibberulus accurately records ambient SST and can be used to reconstruct ancient nearshore conditions. These findings also contribute to the establishment of an environmental baseline, which can be used to examine how environmental changes may have influenced the availability of molluscan taxa that in turn influenced human subsistence practices through time.     

A COMPARISON OF METHODS FOR ESTABLISHING FATTY ACID CONCENTRATION GRADIENTS ACROSS POTSHERDS: A CASE STUDY USING LATE BRONZE AGE CANAANITE AMPHORAE*

Canaanite amphorae fragments in fabrics believed to be associated with the bulk transport of vegetable oils from the fourteenth‐century BC site of Amarna, Egypt, have been examined. A comparison is made between solvent extraction, saponification and the use of TMTFTH (m‐trifluoromethylphenyl)trimethylammomum hydroxide, used here for the combined extraction and derivatization of ceramic‐absorbed organic residues. Extracts were studied using gas chromatography and gas chromatography‐mass spectrometry. The extraction of fatty acids from small ceramic samples has established concentration gradients of absorbed organic matter from the inner to the outer surfaces of the sherds.     

A COMPARISON OF INDUCTIVELY-COUPLED PLASMA EMISSION SPECTROMETRY AND ATOMIC ABSORPTION SPECTROMETRY ANALYSIS ON STANDARD REFERENCE SILICATE MATERIALS AND CERAMICS

Analyses by inductively coupled plasma atomic emission spectrometry and atomic absorption spectrometry of 22 ceramic standards and sherds are compared. Further data from analyses of one of the ceramic standards analysed by both methods are also discussed. The results show that for most major elements, the methods are comparable, but that use of common standards would be advisable if data from the two methods are to be compared.     

Isotopic evidence for Middle Horizon to 16th century camelid herding in the Osmore Valley,Peru

Archaeological and zooarchaeological data indicate that camelid pastoralism was a subsistence and economic mainstay of Middle Horizon and more recent cultures in the Osmore region of southern Peru. However, it is not known whether camelids were primarily herded in highland puna pastures or near lower elevation sites in the middle valley or along the coast. This research examines the elevation of archaeological camelid herding in the Osmore Valley using stable isotope analysis. Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios were measured on 28 archaeological camelid bone samples from the Middle Horizon sites of Cerro Baúl and Cerro Mejía, the Late Intermediate site of Yaral and the late pre‐Hispanic to Colonial period site of Torata Alta. Twenty‐three archaeological camelids have δ¹³C and δ¹⁵N values similar to five modern camelids maintained in highland puna pastures. In contrast, three camelids from the high status Wari site of Cerro Baúl, and two from Yaral have unexpectedly high δ¹³C and/or δ¹⁵N values outside the expected range for camelids pastured in highland puna habitats. The results may be explained by differences in foddering practices, altitudinal herding range or climatic conditions. Strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) were also assessed to infer pasture elevation using the camelid remains from Cerro Baúl (n = 11). One individual in this sub‐sample exhibits a non‐local ⁸⁷Sr/⁸⁶Sr value indicative of an origin in the highland puna region east or south of Lake Titicaca. It was not possible to further distinguish between camelids herded in lower to middle elevation habitats outside the Lake Titicaca basin using ⁸⁷Sr/⁸⁶Sr values. This study suggests that multiple isotope proxies may be used to identify animals primarily pastured in lowland coastal versus highland puna (> 4000 masl (meters above sea level)) habitats, but are less useful at distinguishing between animals pastured in lower to middle elevation settings. Copyright © 2010 John Wiley & Sons, Ltd.     

Accurate identification of the pastry contained in a ceramic pot excavated from Jurou Li's grave from the Jin dynasty (1115–1234 ce) in Xi'an,Shaanxi, China

In order to identify accurately the circular object contained in the ceramic pot excavated from Jurou Li's grave of the Jin dynasty (1115–1234 ce ) in Xi'an, Shaanxi, China, mass spectrometry was applied to determine the amino acid sequences of the residual proteins extracted from the sample, after preliminary starch grain analysis. The sequences were searched against a standard protein sequence database. The proteins extracted were identified as originating from domesticated barley (Hordeum vulgare), soybean (Glycine max), and fermentative microorganisms (Kluyveromyces lactis, Lipomyces starkeyi, Wickerhamomyces ciferrii, Nadsonia fulvescens and Zygosaccharomyces rouxii). These findings indicate that the extremely degraded object in the ceramic pot was made from barley by fermentation with the addition of soy sauce, providing direct evidence of culinary culture in the Jin dynasty.     

PANTELLERIAN WARE: A COMPREHENSIVE ARCHAEOMETRIC REVIEW*

Pantellerian ware is a Late Roman cooking ware whose production centre was established on the island of Pantelleria by the pioneering research of Fulford and Peacock almost 20 years ago ( Peacock 1982 ; Fulford and Peacock 1984 ). Archaeological and archaeometric studies carried out by the authors of the present contribution during the past four years have aimed to fully characterize this ceramic class. Recurrent ceramic forms, their distribution over time and space, their petrographic characteristics and their chemical identity, as well as possible raw materials and their technological properties, were considered. The present paper is a comprehensive review of this archaeometric work and aims to establish a ‘reference group’. Using a representative number of samples of Pantellerian ware that were recently discovered in the island through archaeological field surveys or surface and submarine excavations, it was possible to characterize in detail the compositional variability of this ware in terms of chemistry and petrography. Furthermore, the physical properties of this ceramic type have been defined in order to better understand its performance characteristics, mainly in response to induced thermal stress. In the meantime, the experimental mixing and tempering of locally sampled raw materials have shed light on the ancient manufacturing process and have led to an approximation of the original paste.     

Finding a Relatively Flat Archaeological Site with Minimal Ceramics: A Case Study from Iraqi Kurdistan

ABSTRACT

We present a new technique to detect flat archaeological sites with minimal ceramics using an unmanned aerial vehicle that maps surface stone concentrations. Methods deployed include point pattern analysis of stone concentrations and a machine-learning technique using unsupervised classification of visible stone signature qualities, which are used in simple linear regressions to compare with geophysical and ceramic surface survey results of a site in Iraqi Kurdistan. There is a stronger fit (r^2?=?0.77) between surface stone concentrations and architecture identified by geophysical measurement, while surveyed ceramics show a weaker fit to defined architecture (r^2?=?0.31). Surface stone concentrations are potentially a better proxy than ceramics for determining the presence of past settlement in regions where stone was commonly used, sites are relatively flat, and ceramics are found in low concentrations. The methods advanced here can be scaled to wider areas, particularly in mountainous regions, where surface stone features are present.     

Addressing data comparability in the creation of combined data sets of bioapatite carbon and oxygen isotopic compositions

Before amalgamating published isotope data, comparability should be demonstrated. This paper compares carbon and oxygen isotopic compositions of 30 enamel samples measured by two laboratories. The aims were to see what, if any, isotopic variation was observed, to determine the causes as needed and to correct if possible. Bioapatite was acidified at 90°C in 2006 and at 26°C in 2017, while δ values were corrected via one‐point normalization in 2006 and by two‐point normalization in 2017. One case (of the 30) produced different δ values between the analysis dates, suggesting contamination. Repeated carbon isotope ratio measurements were not meaningfully different. Repeated oxygen isotope ratio measurements were significantly different, even following correction for acid‐carbonate fractionation at different temperatures and the renormalization of 2017 δ values using one point; however, differences were not meaningful for interpretations. Results were used to calculate real interpretative differences (RIDs) for comparing enamel bioapatite as 0.6‰ for δ¹³C values and as 1.6‰ for δ¹⁸O values.     

Calcium isotopes in archaeological bones and their relationship to dairy consumption

The calcium isotope ratios (δ^44/42Ca) of bones from humans and fauna from three archaeological sites, Taforalt, Abu Hureyra, and Danebury, are evaluated in order to assess whether calcium isotope ratios of bones can be used to detect dairy consumption by adult humans. At each site the fauna δ^44/42Ca is the same regardless of species, while the humans have lower δ^44/42Ca than the local animals by 0.24–0.41‰ (site means). However we cannot ascribe this difference to dairy consumption, given this human–faunal difference also occurs in Epipalaeolithic and Mesolithic adult humans, where dairy consumption is unlikely. Rather, this difference appears to be a result of differences in metabolic processes or other aspects of diet between humans and fauna. Minimal isotopic change in sequential acid leaches of bone powders and consideration of the high calcium concentration in bone suggest that bone calcium isotope ratios are not substantially affected by diagenetic change.