Radiocarbon dating of Ohalo II: Archaeological and methodological implications

Charcoal samples from the Early Epipalaeolithic submerged fisher-hunter-gatherers site of Ohalo II have been dated by three laboratories. The samples derive from huts, hearths, a grave and a stone installation. Twenty-five date range between 17,500-21,050 bp and average c. 19,400 bp. The thickness of deposits, the perishable building material (of the huts), the spatial organization of the camp and its rapid cover by sand and water suggest several occupational episodes, lasting not more than tens of years together. The discrepancy between the range of ¹⁴C dates and the real length of occupation are due to the statistical limitations of the dating method.     

MULTIVARIATE MIXTURE OF NORMALS WITH UNKNOWN NUMBER OF COMPONENTS: AN APPLICATION TO CLUSTER NEOLITHIC CERAMICS FROM AEGEAN AND ASIA MINOR USING PORTABLE XRF*

Multivariate techniques and especially cluster analysis have been commonly used in archaeometry. Exploratory and model‐based techniques of clustering have been applied to geochemical (continuous) data of archaeological artefacts for provenance studies. Model‐based clustering techniques such as classification maximum likelihood and mixture maximum likelihood have been used to a lesser extent in this context and, although they seem to be suitable for such data, they either present practical difficulties—such as high dimensionality of the data—or their performance gives no evidence that they are superior to standard methods. In this paper standard statistical methods (hierarchical clustering, principal components analysis) and the recently developed model‐based multivariate mixture of normals with an unknown number of components, are applied and compared. The data set provides chemical compositions of 188 ceramic samples derived from the Aegean islands and surrounding areas.     

THE STUDY OF NABATAEAN ORGANIC RESIDUES FROM MADÂ’IN SÂLIH,ANCIENT HEGRA,BY GAS CHROMATOGRAPHY – MASS SPECTROMETRY*

Four Nabataean samples collected in some of the monumental tombs of Madâ’in Sâlih, ancient Hegra, in Saudi Arabia, have been studied by gas chromatography coupled with mass spectrometry. These samples are textile fragments that are either covered with a black layer or bound together with some black amorphous substance. Fatty acids and triterpenoic compounds were detected. Eight triterpenic compounds were identified: ursa‐9(11),12‐dien‐3‐ol, ursa‐9(11),12‐dien‐3‐one, olean‐9(11),12‐dien‐3β‐ol, β‐amyrone, β‐amyrin, α‐amyrone, α‐amyrin and lupeol. The resinous chemical composition and these pentacyclic alcohols, in considerable proportion, indicate a resin of the Burseraceae family, possibly of the genus Canarium.     

IS THE MACROSCOPIC CLASSIFICATION OF FLINT USEFUL? A PETROARCHAEOLOGICAL ANALYSIS AND CHARACTERIZATION OF FLINT RAW MATERIALS FROM THE IBERIAN NEOLITHIC MINE OF CASA MONTERO*

Casa Montero is a mining complex located outside Madrid (Spain), dated from the Early Neolithic (c. 5400–5000 cal bc ). An area of some 4 ha has been investigated and some 4000 shafts recorded, of which 324 have been excavated. The characterization of its raw flint materials and the establishment of its diagnostic features are indispensable in the reconstruction of the distribution of the mine's products beyond the immediate site. This work reports the geological study of the mine's Miocene flint layers and their petrological characterization. Archaeological samples from the mine's shafts were classified according to macroscopic features and petrological characteristics.     

CHARACTERIZATION OF THE AMPHORAE,STONE BALLAST AND STOWAGE MATERIALS OF THE SHIPS FROM THE ARCHAEOLOGICAL SITE OF PISA–SAN ROSSORE,ITALY: INFERENCES ON THEIR PROVENANCE AND POSSIBLE TRADING ROUTES*

In December 1998, during excavation for the construction of a new building near San Rossore railway station in Pisa, the remains of ancient ships were discovered. These findings have been dated (radiocarbon) to between the end of the 10th century bc and the fifth century ad ( Belluomini et al. 2002 ). Several transport amphorae belonging to the Hellenistic ship, samples of rocks (stone ballast) belonging to ships B, D and the Hellenistic ship, and stowage materials belonging only to ship B have been analysed. The mineralogical and petrographic data of the investigated samples provided information on the possible provenance of the raw materials utilized in the manufacture of the ceramic amphorae, as well as on the provenance of the rock materials found in the ships as ballast and stowage. The compositional data (obtained through XRD, XRF, OM and EPMA) and their statistical analyses suggest that the provenance of the Dressel amphorae belonging to the Hellenistic ship was the Middle Tyrrhenian coast of Italy, and more precisely the area between Tarquinia and Naples, according to the numerous kilns and wine production sites found in this area. The provenance of the volcanic rocks was from southern Tuscany, northern Latium and possibly the Pontine Islands, whereas the intrusive rock possibly comes from the Calabrian–Tyrrhenian coast and/or the Peloritani area. The impure limestones and the dolostone come from southern Tuscany and the Latium coast; the semi‐metamorphic rocks could come from the coast of southern Tuscany, the Tuscan Archipelago or possibly also from the Ligurian coast; only the sample of mylonitized granitoid possibly comes from either the Calabria–Peloritani arc or the Tuscan Archipelago. The stowage materials, consisting of lapilli and scoria of a pyroclastic nature, are sourced from the Neapolitan area. These data might shed some light on the centres of production of the amphorae and of the trading routes followed by the ships, according to the ports of call.     

ROMAN GLASS‐MAKING AT COPPERGATE,YORK? ANALYTICAL EVIDENCE FOR THE NATURE OF PRODUCTION*

Ceramic vessels and associated vitreous debris, excavated at Coppergate, York, UK, have been interpreted as the remains of Roman glass‐making from the raw materials. This paper reports the results of analysis of this assemblage by XRF, ICPS, XRD, SEM– EDAX and thin‐section petrography. These findings suggest that some ceramic vessels, used as crucibles, have been subjected to temperatures up to 1200°C, well above the firing temperatures of the local domestic assemblage from which they were selected. Analysis of quartz‐rich debris, intimately mixed with glass in some samples and in others interleaved with glassy phases, indicates partially reacted glass‐making raw materials, with α‐quartz, tridymite and cristoballite phases represented. This could represent evidence either of a failed attempt to frit the raw materials, or a batch that had not fully fused. Variability in the composition of glass at the site is viewed in the light of glass‐making technology, and possible interpretations concerning this episode are discussed in the light of the archaeological evidence.     

AN UPDATED,MULTI‐METHOD DATABASE OF EPHESOS MARBLES,INCLUDING WHITE,GRECO SCRITTO AND BIGIO VARIETIES*

An updated database of Ephesos marbles including 244 samples from 16 quarrying districts is reported. The unknown Greco Scritto quarries near Hasançavuslar and the Bigio marbles from the quarries of Belevi and of Mt Panayir are also presented. The paper, however, is mostly devoted to the identification of the Ephesos white marbles, whereas the problems posed by the Bigio and Greco Scritto varieties are deferred to future work. The samples have been characterized by isotopic analysis, EPR spectroscopy and additional petrographic and optical properties. Owing to the complex geology of the region, the white marbles of Ephesos exhibit rather inhomogeneous properties and are conveniently classified into four marble groups, which can be almost completely discriminated. The problem of distinguishing the Ephesos white marbles from other similar varieties has been dealt with by statistically comparing the Ephesos samples with all the similar, medium‐grained varieties present in the marble database. Although some of the four Ephesos groups can be reliably identified, general solution of the discriminant problem is difficult. Historical archaeological information is needed to reduce the complexity of the problem by eliminating unlikely provenances. In this way relevant problems, such as the discrimination between Ephesos and Proconnesos marbles, can be solved.     

A REVIEW OF SUPERVISED AND UNSUPERVISED PATTERN RECOGNITION IN ARCHAEOMETRY*

Principal component, cluster and discriminant analysis are multivariate statistical methods that are widely used in archaeometry. They are examples of what are known in some literatures as unsupervised and supervised learning methods. Over the past 20 years or so, a wide variety of other learning methods have been developed that take advantage of modern computing power and, in some cases, have been designed to handle data sets more complex than those often used in archaeometric data analysis. To date, these methods have had little impact on archaeometry. This paper reviews, in a largely non‐technical manner, the ideas behind these newer methods; illustrates their use on a variety of data sets; and attempts to assess their potential for future archaeometric use.     

IDENTIFICATION OF STONE BLOCKS USED FOR THE BUILDING OF THE THYSDRUS AND THAPSUS AMPHITHEATRES IN TUNISIA

In Tunisia, the largest amphitheatre (known as the Coliseum) at Thysdrus (El Djem), with some parts of the second amphitheatre, and the Thapsus amphitheatre have been built with squared stone blocks (opus quadratum). The petrographic and geotechnical analyses of the samples taken from the amphitheatre blocks show that these blocks belong to the Tyrrhenian and to the Mio‐Pliocene age. Ancient quarries have been found on the Tyrrhenian dune line between Hiboun and Al Alya, at a distance of 30 km from Thysdrus, from which the Tyrrhenian blocks have been extracted. Concerning the Mio‐Pliocene blocks, they have most likely been cut from just one ancient quarry found in the hill of Ksour Essaf. The height of almost all of the measured blocks from the Thysdrus Coliseum is equal to the Punic cubit used at Carthage (50 cm), and the height of the measured blocks from the Thapsus amphitheatre is also equal to the Punic cubit (50 cm), or very close to the Roman cubit (45 cm).     

COMPOSITIONAL CHARACTERIZATION OF FRENCH LIMESTONE: A NEW TOOL FOR ART HISTORIANS*

Limestone from quarries known to medieval craftsmen and from the monuments they built and embellished, as well as from carvings now in museum collections, has been characterized by neutron activation analysis. Specimens from 38 quarries in the Lutetian and Jurassic limestone formations of France and from sculptures in American and French museums have been tested, and the results have been compiled in a data base to which art historians may refer when attempting to determine provenance for sculptures. Multivariate statistical analysis of concentration data shows stone from a particular quarry in the Paris basin to be compositionally homogeneous and distinguishable from other quarries in the same formation. The same approach to data related to quarries near the Burgundian abbey of Cluny finds general agreement between classifications based on compositional and on petrographic data, but the number of samples available for analysis at the time of writing was insufficient to achieve the finer distinctions reported for the Paris basin.     

MOLECULAR AND ISOTOPIC DEMONSTRATION OF THE PROCESSING OF AQUATIC PRODUCTS IN NORTHERN EUROPEAN PREHISTORIC POTTERY*

A number of charred surface residues, adhering to ceramic containers, were obtained from various coastal and inland sites in north‐west Europe dating from the sixth to the fourth millennium cal bc . In order to investigate the use of these vessels and in particular to identify any marine products, the residues were subjected to carbon and nitrogen stable isotope analysis. Variation in carbon isotope ratios between different samples indicated that some vessels may have been used to process marine products. This analysis was corroborated by specific identification of aquatic products following structural and isotopic characterization of lipids extracted from selected samples.     

RADIOCARBON DATES FOR BEESWAX FIGURES IN THE PREHISTORIC ROCK ART OF NORTHERN AUSTRALIA

Accelerator mass spectrometry radiocarbon ages have been taken for a test suite of small samples of material removed from some of the ‘beeswax’art figures found in rock shelters in northern Australia. The results indicate that we can reliably date this unique form of rock art with no noticeable damage. We had not expected to find figures of any great antiquity, and so we were surprised to find that the ages obtained spanned the time period from the recent past to about 4000 BP.     

Radiocarbon dating: Some practical considerations for the archaeologist

The article is divided into four main sections in each of which a key aspect of radio-carbon dating is discussed with emphasis on the practical implications for users of dates. The four topics which the article attempts to deal with are, in turn, (i) the effect on the radiocarbon timescale of the variations in atmospheric ¹⁴C now known to have occurred in the past and the role of other absorlute dating methods in investigating these, (ii) laboratory measurement of ¹⁴C, (iii) selection of optimum samples for dating and (iv) some of the limitations of the final dates. The theme is essentially that the technical difficulties of radiocarbon measurement in the laboratory have been overcome to the extent that the physical measurements can now be made with high precision, that is to within ±1% or better, as a routine. Thus, it is more important than ever (a) that only reliable samples having very firm associations should be dated and (b) that pretreatment of such samples by the dating laboratory to remove any age contaminants should be completely effective. However, in addition to the recognized statistical limitations, the absolute accuracy of radio-carbon dating is limited by the past ¹⁴C variations. Coupled with the requirements of proper association and pretreatment of samples is the long-term need to establish an overall correlation between radiocarbon and calendar years. At present this is still a matter for final agreement by the laboratories concerned. Meanwhile, when all possible steps have been taken to ensure the reliability of the date messurements, these can strictly only be compared with one another in terms of radiocarbon years bp. In practice this is often too restrictive but any attempts at calibration must be regarded as approximations for the time being. In this article the lower and upper case notation advocated in Antiquity46, 265, for radiocarbon and calendar years respectively has been followed.     

KIMMERIDGE JET—A POTENTIAL NEW SOURCE FOR BRITISH JET

Archaeological artefacts identified as jet are often assumed to have originated from the principal British source, which is at Whitby in Yorkshire. Geological samples of jet have also been found within the Kimmeridge Blackstone in Dorset—a seam of oil shale which has been worked since prehistoric times to produce artefacts similar to those made from jet. This paper discusses the geology and geochemistry of jet samples from both Whitby and Kimmeridge, and shows that the geological samples can be discriminated by differences in their organic components, as elucidated by Fourier transform infrared spectroscopy and pyrolysis-gas chromatography/mass spectrometry.     

TRACE ELEMENT GEOCHEMISTRY OF NATIVE COPPER FROM THE WHITE PINE MINE,MICHIGAN (USA): IMPLICATIONS FOR SOURCING ARTEFACTS*

Eighty-five samples of native copper from the White Pine mine in upper Michigan were analysed by neutron activation to document geochemical variability within a single locality. Silver, sodium, antimony and scandium contents vary by two orders of magnitude, whereas arsenic values vary by three orders of magnitude. This variability reinforces the need for provenance studies of artefacts to examine sufficient samples to test for heterogeneity within the source area. The White Pine suite contains some of the most impure native copper that has been analysed to date. Arsenic and silver values of these impure samples overlap with those of European coppers, but consideration of several elements can still distinguish native copper from European copper.     

WASTE GLASS,VESSELS AND WINDOW‐PANES FROM THAMUSIDA (MOROCCO): GROUPING NATRON‐BASED BLUE–GREEN AND COLOURLESS ROMAN GLASSES

A collection of window‐panes, vessels and alleged waste from Thamusida has been investigated by OM, SEM–EDS, ICP–MS, ICP–OES and XAS at the Fe–K and Mn–K edges. Glass samples have been characterized as natron‐based soda–lime–silica glasses, with low magnesium and low potassium. The results have been compared with 43 reference groups available for ‘naturally coloured’ and colourless glasses of both Roman and later ages. Two main types were distinguished: RBGY 1 (R oman B lue–G reen and Y ellow 1) and RBGY 2 (R oman B lue–G reen and Y ellow 2). Given their compositional similarity to the Levantine I or, to a lesser extent, HIMT glasses, the Syrian–Palestinian coast for RBGY 2 and Egypt for the RBGY 1 have been suggested for their provenance. Most Thamusida samples have been assigned to the RBGY 2 type. A small group of Thamusida colourless vessels was included into the RC (R oman‐C olourless) compositional field; the latter still being defined. The alleged waste pieces may define a local production that should have been of secondary type. The investigations performed on local raw materials seem to discount the possibility of a primary glass‐making site. XAS measurements determined that Fe²⁺ contents ranging between 30 and 52% are able to assure an aqua blue colour; below 30%, the glasses turn light green or light yellow.     

THE BAYESIAN APPROACH TO THE INTERPRETATION OF ARCHAEOLOGICAL DATA

Archaeologists are increasingly becoming aware of an approach to data investigation known as Bayesian statistics. In this paper we outline both the philosophical and statistical background to the approach. We show that it provides a logical and coherent framework in which to make inferences on the basis of both data and a priori expert knowledge. We note that adoption of the Bayesian framework is particularly timely since there have been recent dramatic developments in numerical methods which mean that a number of previous implementation problems have now been solved. As a result, many questions of archaeological interest, which require the use of complex statistical models, are being investigated using this methodology. We use a variety of recently published examples from a range of archaeological areas to illustrate the type of questions that can be answered and the nature of the methodologies used, and we make comparisons with the results obtained using more traditional statistical techniques.     

NORTH APULIAN COARSE WARES AND FINE PAINTED WARES: A REAPPRAISAL ACCORDING TO NEW DATA FROM HERDONIA AND CANUSIUM

Late Antique coarse cooking wares and painted fine wares found at Herdonia (second half of the fourth century to mid‐fifth century ad ) and Canusium (late sixth century to early seventh century ad ) have been chemically and mineralogically characterized. A total of 74 samples (40 of coarse ware and 34 of fine painted ware) was investigated through optical microscopy, scanning electron microscopy, X‐ray powder diffraction, inductively coupled plasma optical emission spectrometry, inductively coupled plasma mass spectrometry, neutron activation analysis and X‐ray fluorescence. A new statistical method, namely the classification tree methodology, was used for the treatment of geochemical data. The characterization of the Herdonia and Canusium assemblages was combined with a review of earlier results obtained for San Giusto and Posta Crusta, in order to get an insight on Late Antique ceramic trades in northern Apulia. It appears possible to reconstruct a production pattern organized at multiple production sites, both rural and urban, that exploited similar raw material deposits, specialized in certain productions, and commercialized products at different geographical scales. Imports from outside northern Apulia may be identified for coarse wares. A likely area of production is difficult to establish; however, the northern Adriatic coast and the area of Greece may be suggested.     

1H‐NMR AND 31P‐NMR CHARACTERIZATION OF THE LIPID FRACTION IN ARCHAEOLOGICAL OINTMENTS

Lipids are a broad group of naturally occurring molecules, which includes fats, oils, waxes, sterols, terpenes, fat‐soluble vitamins, monoglycerides, diglycerides, phospholipids and others. Lipids have been widely used in human history and they are often present in archaeological finds. In particular, in the field of medicine and cosmetics, lipids have been employed as base in the preparation of unguents, salves and balms. The characterization of these products and their degradation products induced by ageing is important for an understanding of the ancient pharmaceutical techniques and to assess the state of conservation. ¹H‐NMR and, for the first time, ³¹P‐NMR spectroscopy have been applied to the characterization of such compounds. By derivatization of the samples with 2‐chloro‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaphospholane, it is possible to recognize, quantify and evaluate the degradation degree of lipids in archaeological unguent samples. With this new approach, lipids have been recognized in 17th‐century archaeological ointments from the Aboca Museum. Moreover, severe hydrolysis and oxidation markers have been detected.