ORGANIC RESIDUE ANALYSIS IN ARCHAEOLOGY: THE ARCHAEOLOGICAL BIOMARKER REVOLUTION*

Organic residue analysis utilizes analytical organic chemical techniques to identify the nature and origins of organic remains that cannot be characterized using traditional techniques of archaeological investigation (because they are either amorphous or invisible). The field is founded upon the principle that the biomolecular, or biochemical, components of organic materials associated with human activity survive in a wide variety of locations and deposits at archaeological sites. The archaeological information contained in organic residues is represented by the biomolecular components of the natural products that contribute to the formation of a given residue. By applying appropriate separation (chromatographic) and identification (mass spectrometric) techniques, the preserved, and altered, biomolecular components of such residues can be revealed. Once identified, the Archaeological Biomarker Concept can be applied, wherein the structure and even isotopic composition(s) of a given biomolecule or suite of biomolecules (the ‘chemical fingerprint’) can be related to the compositions of organisms exploited by humans in the past. As the organic residue field emerges from its pre‐paradigmatic phase, and the organic residue revolution gathers pace, the way is open for challenging many long‐held archaeological hypotheses and offering new perspectives on the study of human activity in the past.     

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.     

EVIDENCE FOR THE MIXING OF FATS AND WAXES IN ARCHAEOLOGICAL CERAMICS

Lipid residues from two Late Saxon/early medieval ceramic vessels recovered from excavations at West Cotton, Raunds, Northamptonshire, U.K., have been investigated by high-temperature gas chromatography (GC) and GC/mass spectrometry (GC/MS). The solvent extracts of sherds sampled from different points on each vessel (i.e., base, body and rim) were analysed quantitatively and qualitatively and compounds were identified which were characteristic of beeswax and animal fat. Furthermore, by determining the sites of accumulation of the specific lipid types and their concentrations in different parts of the vessels it can be inferred that the beeswax was added to the vessels prior to the addition of the fat. It was concluded that the two vessels performed different functions in antiquity.     

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.     

THE CHRONOSTRATIGRAPHY AND GEOARCHAEOLOGICAL SIGNIFICANCE OF AN ALLUVIAL GEOARCHIVE: COMPARATIVE OSL AND AMS 14C DATING FROM GREECE*

The Basin of Phlious in southern Greece is known for its thick colluvial and alluvial deposits from the Holocene. It offers a good opportunity to reconstruct the history of Holocene soil erosion and its interaction with historical farming activities. In this study, we present new results based on optically stimulated luminescence (OSL) dating from the Basin of Phlious. The comparison between OSL and ¹⁴C AMS ages shows good agreement, and demonstrates the need for the detection of insufficiently bleached OSL samples in order to obtain accurate results. The discovery of a Neolithic site, buried under thick alluvial deposits, confirms the hitherto postulated Neolithic human impact on the landscape.     

The Preservation and Identification of Piñon Resins by GC‐MS in Pottery from the Western Great Basin

Gas chromatography — mass spectrometry analysis of a sherd from the Nevada Test Site revealed a high quantity of terpenes, including sesquiterpenoids and diterpenoids, demonstrating that piñon resins were prepared in the pot in prehistoric times. The presence of these biomarkers allowed for a very specific identification of the products prepared in the pot, a level of detail not often achieved in lipid residue analysis. That the terpenes are relatively unoxidized demonstrates that they are quite stable over long periods of time. The study also shows that sherds on the surface of archaeological sites can preserve lipids and terpenes and are amenable to organic residue analysis.     

NEUTRON ACTIVATION PATTERNING OF ARCHAEOLOGICAL MATERIALS AT THE NATIONAL CENTER FOR SCIENTIFIC RESEARCH ‘DEMOKRITOS’: THE CASE OF BLACK‐ON‐RED NEOLITHIC POTTERY FROM MACEDONIA,GREECE

A short history of the application of NAA in the characterization of archaeological materials at the National Center for Scientific Research ‘Demokritos’, Athens, is presented. NAA was first applied in archaeology in 1974 at the Radioanalytical Laboratory, and since 1989 has been one of the primary analytical techniques of the ‘Demokritos’ archaeometry programme. A case study is also presented, concerning chemical patterning of the black‐on‐red Neolithic pottery class from Macedonia. Four chemical groups were identified, each corresponding to a different area of production. It is shown that this standardized concept of pottery technology and style was spread out within at least eastern Macedonia.     

Chemical Alteration and Use of Beeswax Through Time: Accelerated Ageing Tests and Analysis of Archaeological Samples from Various Environmental Contexts

In order better to interpret the chemical composition of ancient organic residues and artefacts containing beeswax, the degradation of this raw material was accelerated in the laboratory by controlled heating. During the course of degradation, deposits were condensed above the beeswax. Both degraded beeswax and these deposits were analysed. These experiments definitively proved that n‐alkane depletion is due to a sublimation process that depends on the molecular weight of these hydrocarbons. The formation of benzoic and cinnamic derivatives due to the degradation of flavonoid precursors initially present in beeswax has also been highlighted for the first time. The analysis of samples from Neolithic and Roman periods led to the identification of beeswax characterized by different degradation patterns linked to their environmental context.     

HUMAN MOBILITY AT THE EARLY NEOLITHIC SETTLEMENT OF VAIHINGEN,GERMANY: EVIDENCE FROM STRONTIUM ISOTOPE ANALYSIS*

As evidence concerning human mobility during the transition to agriculture in central Europe, we present the results of strontium isotope analysis of human skeletons from the Neolithic village of Vaihingen, Germany. We find significantly more ‘non‐local’⁸⁷Sr/⁸⁶Sr values from humans buried in a Neolithic ditch surrounding Vaihingen than from those buried within the settlement. These results fit with previous studies showing a correlation between burial circumstances and strontium isotope signatures from LBK cemeteries of southwestern Germany ( Price et al. 2001 ; Bentley et al. 2002 ). A pilot study of Neolithic animal teeth from Vaihingen suggests that either ‘local’⁸⁷Sr/⁸⁶Sr signatures were more variable than the analysed human bones suggest, or that these domestic animals themselves were mobile, perhaps ranged by mobile pastoralists.     

GC–MS ANALYSIS AND FATTY ACID RATIOS OF ARCHAEOLOGICAL POTSHERDS FROM THE WESTERN GREAT BASIN OF NORTH AMERICA*

The study of organic residues in archaeological pottery has focused on fatty acids due to their relative stability and longevity. However, even these compounds are subject to degradation, which makes assignment of residues to original foods problematic. This paper suggests that the use of ratios of fatty acids that degrade at roughly the same rate can be useful to identify very general categories of foods. It compares independent information on pot function based on ethnography and engineering/technological studies to that reconstructed based on extracted fatty acid ratios. The results support the notion that Great Basin pots were used primarily to boil seeds and that pot shape and pot function were related.     

CHARACTERIZATION OF NATURAL PRODUCTS ON NATIVE AMERICAN ARCHAEOLOGICAL AND ETHNOGRAPHIC MATERIALS FROM THE GREAT BASIN REGION,U.S.A.: A PRELIMINARY STUDY

Although documentary evidence provided by ethnographers makes reference to the source of adhesives, sealants, dyestuffs and medicines used by the communities of the Great Basin, much of it is sporadic and unspecified. However, observations of amorphous deposits surviving on stone tools, ceramics, basketry and wooden artefacts have prompted an investigation of their identity, procurement and use. The aim initially is to study samples from a number of archaeological and ethnographic contexts from the region. Comparative material includes higher plant and insect resins. The study provides a unique opportunity to document use patterns in plant and animal resources in the Great Basin region.     

COMPOSITIONAL VARIATIONS IN AGED AND HEATED PISTACIA RESIN FOUND IN LATE BRONZE AGE CANAANITE AMPHORAE AND BOWLS FROM AMARNA,EGYPT*

This study examines resinous deposits from the interior surfaces of sherds of imported Canaanite amphorae and locally produced bowls from the 18th Dynasty site of Tell el‐Amarna, Egypt. Archaeological evidence indicates that the Canaanite amphorae were used for resin transport, whilst the bowls are associated with burning resin as incense. A number of characteristic triterpenoids identify all the resinous deposits from both vessel types as Pistacia spp. No other resins were observed and there was no evidence of mixing with oils or fats. The composition of the archaeological resins is more complex than that of modern pistacia resin, due to degradation and generation of new components. Experimental heating alters the relative abundance of the triterpenoid composition of modern pistacia resin. One component, the triterpenoid 28‐norolean‐17‐en‐3‐one, is produced by such heating; however, an increase in its relative abundance in ancient samples is not matched by the archaeological evidence for heating. It is therefore not possible to use this component reliably to identify heated resin. However, additional unidentified components with a mass spectral base peak at m/z 453 have been associated with seven (out of 10) bowls and are not observed in resins associated with Canaanite amphorae. It is proposed that these components are more reliable molecular indicators of heating.     

THE PROVENANCE OF OBSIDIAN ARTEFACTS FROM THE WĀDĪ ATH‐THAYYILAH 3 NEOLITHIC SITE (EASTERN YEMEN PLATEAU) BY LA–ICP–MS

The geological sources of obsidian in the Red Sea region provide the raw material used for the production of obsidian artefacts found in prehistoric sites on both sides of the Red Sea, as far afield as Egypt, the Persian Gulf and Mesopotamia. This paper presents the chemical characterization of five obsidian geological samples and 20 prehistoric artefacts from a systematically excavated Neolithic settlement in highland Yemen. The major element concentrations were determined by SEM–EDS analysis and the trace element concentrations were analysed by the LA–ICP–MS method, an almost non‐destructive technique capable of chemically characterizing the volcanic glass. A comparison of archaeological and geological determinations allows the provenance of the obsidian used for the Neolithic artefacts to be traced to definite sources in the volcanic district of the central Yemen Plateau.     

RELATIONSHIP BETWEEN THE COLORATION AND THE FIRING TECHNOLOGY USED TO PRODUCE SUSA GLAZED CERAMICS OF THE END OF THE NEOLITHIC PERIOD*

Ancient decorated potteries from Susa (Mesopotamia) dating from 4200 to 3700 bc , were studied in order to determine the origin and the nature of the raw materials used, and to identify the technological processes applied to make the ceramic bodies and their decorations. Bulk compositions were determined by particle induced X‐ray emission (PIXE), while the microstructure and the mineralogical phases were studied using scanning electron microscopy (SEM), energy dispersive X‐ray analyses (EDX) and X‐ray powder diffraction (XRD). The results showed that the raw materials used to elaborate these potteries were similar for all the ceramic bodies (carbonates and iron and magnesium‐rich clays containing sand), and for all the decorations (iron oxides, silica, potassic and alumina sources). The variations of coloration of the ceramics and of their decorations were due to different firing temperatures. The ranges of firing temperatures used by potters were evaluated on the basis of mineral stability domains.     

MARINE RESOURCES IN THE MESOLITHIC AND NEOLITHIC AT THE GROTTA DELL’UZZO (SICILY): EVIDENCE FROM ISOTOPE ANALYSES OF MARINE SHELLS*

Oxygen isotopes in shell carbonate samples from the marine rocky‐shore intertidal gastropod Monodonta turbinata (Born) are investigated in both modern analogue specimens and in archaeological specimens from the Grotta dell’Uzzo (Sicily). Variations in shell edge values of δ¹⁸O in living specimens collected monthly over two years are closely correlated with monthly seawater temperatures measured at the time of collection, showing that the species can be used for palaeoseasonality studies. Analyses of shell edge δ¹⁸O values in archaeological specimens, from Mesolithic through to early Neolithic phases at the Grotta dell’Uzzo, enabled the inference of various seasons of collection of shellfish and how such seasonality varies between the different phases of occupation. Interesting similarities and differences exist between the seasons of marine shellfish exploitation and the seasons inferred from the vertebrate zooarchaeological assemblages. A major inference drawn from the analyses and discussion is that the exploitation of all marine resources (fish and shellfish) increased in the later Mesolithic and early Neolithic periods.     

COOKING AND PAINTED WARE FROM SAN GIUSTO (LUCERA,FOGGIA): THE PRODUCTION CYCLE,FROM THE SUPPLY OF RAW MATERIALS TO THE COMMERCIALIZATION OF PRODUCTS*

Archaeological excavation at the San Giusto site (Lucera, Italy) has unearthed a Late Antique kiln that was most certainly dedicated to the production of cooking ware. An archaeometric study of numerous specimens of cooking and painted ware found at this site was carried out using optical microscopy, scanning electron microscopy, micro‐Raman spectroscopy, X‐ray diffraction, X‐ray fluorescence, inductively coupled plasma mass and optical emission spectrometry and instrumental neutron activation analysis. The integration of historical–archaeological data with archaeometric data has revealed that these specimens can be attributed to the San Giusto site. Furthermore, the production cycle of this ware can thus be reconstructed: from the diversified supply of raw materials (fluvial and marine sediments), to the relatively complex preparation of the paste, to firing at variable temperatures (600–750°C for cooking ware; 850–1050°C for painted ware).     

FROM SUSA TO ANURADHAPURA: RECONSTRUCTING ASPECTS OF TRADE AND EXCHANGE IN BITUMEN‐COATED CERAMIC VESSELS BETWEEN IRAN AND SRI LANKA FROM THE THIRD TO THE NINTH CENTURIES AD*

In contrast with artefactual studies of long‐distance trade and exchange in South Asia during the Prehistoric and Early Historic periods ( Ardika et al. 1993 ; Gogte 1997 ; Krishnan and Coningham 1997 ; Tomber 2000 ; Gupta et al. 2001 ; Ford et al. 2005 ), few scientifically orientated analyses have focused on artefacts from the region's Historic period. During excavations at the ancient city of Anuradhapura, Sri Lanka, a number of buff ware ceramics with a putative organic coating on the interior were recovered ( Coningham 2006 ). Dated stylistically to between the third and ninth centuries ad , analysis of the coatings using gas chromatography–mass spectrometry (GC–MS) and stable isotope analysis (carbon and deuterium) confirmed that the coatings are bitumen—an organic product associated with petroleum deposits. There are no known bitumen sources in Sri Lanka, and biomarker distributions and isotopic signatures suggest that the majority of the samples appear to have come from a single bitumen source near Susa in Iran. The relationship between the bitumen coatings and the vessels is discussed, and it is suggested that the coatings were used to seal permeable ceramic containers to allow them to transport liquid commodities. This study enhances our knowledge of networks of trade and exchange between Sri Lanka and western Asia during Historic times.     

AN EVALUATION OF ANALYTICAL AND INTERPRETATIVE METHODOLOGIES FOR THE EXTRACTION AND IDENTIFICATION OF LIPIDS ASSOCIATED WITH POTTERY SHERDS FROM THE SITE OF SAGALASSOS,TURKEY*

Three lipid analysis methods were applied to extracts of archaeological potsherds from the ancient city of Sagalassos, south‐west Turkey. In the fatty acid methyl ester fraction, obtained by selective transesterification of acylglycerols, the ratio of methyl palmitate to methyl stearate was determined. Secondly, by means of gas chromatography– combustion–isotope ratio mass spectrometry (GC–C–IRMS), stable carbon isotope ratios were measured for the same methyl esters. Finally, triglyceride composition was determined via high‐performance liquid chromatography–mass spectrometry (HPLC–MS). All three methods can be used to trace the origin of animal fat. Agreement between them is reasonable, especially in recognizing ruminant adipose fat. One sample was found to be of dairy origin using both GC–C–IRMS and HPLC–MS. The advantages of the various methods are discussed. Variations in lipid composition were observed between samples from different periods and excavated in diverse areas within the city of Sagalassos.