ARCHAEOLOGICAL PETROLOGY AND THE ARCHAEOMETRY OF LITHIC MATERIALS*

For 50 years, archaeologists and physical scientists have been dating, determining the composition of and measuring stone tools, and reporting them in Archaeometry and many other journals. In Archaeometry specifically, the number of papers devoted to the analysis of lithic material has increased at least 30 times since 1958 and volume 1. This is a reflection not only of an increase in the number of scholars devoting their time to the archaeometry of stone, but also of increases in the quality and quantity of instrumental technology available to researchers in the field.     

FIFTY YEARS OF LUMINESCENCE DATING*

Luminescence techniques for dating both heated materials (e.g., pottery and burnt stone) and sediments have gone through three phases in the past 50 years. The first 22 years, from 1957 to 1979, were devoted to thermoluminescence (TL) techniques applied to heated material. In the next six years, from 1979 to 1985, it was found that TL dating could be applied to sediments. However, the TL signals of both quartz and feldspar grains observed for modern sediments were small, but were not zero, thus making them useful only for older sediments. A new luminescence signal that was totally zeroed by exposure to sunlight for a relatively short period of time, a few hours or less, was found; this led to the development of optically stimulated luminescence (OSL) dating techniques in 1985. Further developments have continued to the present day. Within the past 22 years, 1999 was also a year with major developments. A reliable procedure for single aliquots of quartz that have a rapidly bleached (‘fast’) OSL component was formalized and an instrument that allowed rapid measurement of equivalent doses for single grains was constructed. These developments have led to OSL becoming a major dating tool in Quaternary geology, at least for the past 100 000 years, and in archaeology, particularly as related to the dispersal of modern humans.     

MATHEMATICS,STATISTICS AND ARCHAEOMETRY: THE PAST 50 YEARS OR SO*

This review of developments in the use of mathematics and statistics in archaeometry over the past 50 years is partial, personal and ‘broad‐brush’. The view is expressed that it is in the past 30 years or so that the major developments have taken place. The view is also expressed that, with the exception of methods for analysing radiocarbon dates and increased computational power, mathematical and statistical methods that are currently used, and found to be useful in widespread areas of application such as provenance studies, don't differ fundamentally from what was being done 30 years ago.     

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.     

THE EFFICIENT COMPUTATION OF UNBIASED MAHALANOBIS DISTANCES AND THEIR INTERPRETATION IN ARCHAEOMETRY*

This paper argues for cross-validation to reduce bias in estimating Mahalanobis distances of individuals to groups, a particular problem with small sample sizes. Formulae for the efficient computation of cross-validated distances, which avoid excessive matrix inversion, are given. The use of Mahalanobis distances as measures of consistency, or as indications of outlying values, is described. The little-known technique of gamma plotting is outlined and discussed as an aid to interpreting distances in these terms. Both cross-validation and gamma plotting are illustrated in an example on marble composition.     

COPPER AND BRONZE DURING THE ENEOLITHIC AND EARLY BRONZE AGE: A METALLOGRAPHIC EXAMINATION OF AXES FROM THE NORTHALPINE REGION*

This paper presents the results of a metallographic examination of Eneolithic and Early Bronze Age axes from the Northalpine region of central Europe. During this period, different types of copper were in use: arsenical copper, Fahlerz copper and tin bronze. We examine if and to what extent the different properties of the metals used were known to prehistoric metalworkers and actively manipulated in the production of the axes. The development of methods of casting and smithing is discussed. Both aspects contribute to our understanding of the nature of prehistoric technological change. During the Early Bronze Age of the Northalpine region, different traditions of early metallurgy can be identified, which differ in their use of Fahlerz copper, their attitude towards tin alloying and the use made of tin bronze in the production of the axes. These traditions can only be adequately described by reference to both composition—that is, access to different types of copper as well as tin—and knowledge of the production techniques provided by metallographic data.     

IN VITRO DECOMPOSITION OF BONE COLLAGEN BY SOIL BACTERIA: THE IMPLICATIONS FOR STABLE ISOTOPE ANALYSIS IN ARCHAEOMETRY*

To understand biogenic collagen type I decomposition and to establish how diagenesis may bias archaeometric data, modern mammalian bone was inoculated with a selection of ubiquitous soil bacteria. The presence of exogenous microbial biomass in the inoculated specimens was then checked microscopically prior to collagen extraction. The experimentally degraded bone collagen showed altered amino acid compositions, attributable to the selective breakdown of certain amino acids by the bacteria. While both the bulk collagen extract and the single amino acids exhibited shifts to more negative δ¹³ C-values, enrichment was recorded for general δ¹³ N, and a depletion trend relative to unaltered collagen was observed for individual amino acid δ¹³ N. One explanation for the enrichment of the global δ¹⁵N-values is cleavage of peptide bonds, which leaves ¹⁵ N within the substrate, while the change of ¹³C is mostly due to the altered amino acid composition. On the other hand, possible repolymerization of cleavage products under experimental conditions may also be responsible for the depletion trend of individual amino acid δ¹³C- and δ¹⁵ N-values. This paper discusses the results as a basis for the development of a method for the reconstruction of the isotopic abundance of the original collagen, using the amino acid composition of the degraded product, the contribution of individual amino acids to its global δ-values and of isotope discriminations implied in the microbial decomposition.     

ROCK SURFACE HARDNESS AS AN INDICATION OF EXPOSURE AGE: AN ARCHAEOLOGICAL APPLICATION OF THE SCHMIDT HAMMER*

A Schmidt Hammer was employed in evaluating the surface hardness of rocks which line ancient anthropogenic pit features, known as Pukaskwa pits, on the north shore of Lake Superior, Canada. This technique offers a possible new method of producing relative ana absolute dates for such exposed stone features Analysis of the data has provided a relative chronology for the pit features, representing two distinct construction phases. The range of absolute dates generated from the data indicates that the pits were likely constructed by Blackduck peoples c. 900 to 400 years BP.     

DETECTION OF ANCIENT MARBLE FORGERY: TECHNIQUES AND LIMITATIONS*

Since 1960, scientific results have replaced aesthetic judgements in marble authentication studies and the technology to perform analytical tests on micro‐samples has developed rapidly. However, no single method can be used to determine the authenticity of a piece of marble. A ‘detective‐like’ investigation is usually adopted by using optical microscopy, ultraviolet‐induced fluorescence, provenance determination techniques and mineralogical, chemical and morphological analyses of the patina. A newly proposed thermoluminescence methodology calculates the ‘burial age’ of recently excavated objects or distinguishes artefacts exposed to sunlight since antiquity from those exposed recently. The technique shows a lot of potential; however, much work remains to be done.     

ACCESSING PAST BELIEFS AND PRACTICES: THE CASE OF LEMNIAN EARTH*

Lemnian Earth, a medicine in the shape of a stamped clay tablet (sphragis) from Lemnos, northeastern Greece, was much valued in antiquity and in the post‐medieval period as an antidote to poison and a treatment for other ailments. Although it was among the first archaeological materials to be subjected to chemical analysis (in 1807), there is still no clear understanding as to what made Lemnian Earth an effective medicine. We argue that Lemnian Earth, the artefact, was not the same as Lemnian Earth, the raw material. We suggest a composition for the artefact by scrutinizing the documentary evidence for its properties and by considering the geochemical processes that led to the formation of the raw material and the ritual relating to its extraction. The study of the latter highlights the need for archaeological materials scientists to recognize ritual as a possible manifestation of physical and chemical processes carried out within the framework of past beliefs and practices.     

POST‐MEDIEVAL CRUCIBLE PRODUCTION AND DISTRIBUTION: A STUDY OF MATERIALS AND MATERIALITIES*

This paper is concerned with the manufacture and trade of post‐medieval crucibles (14th–19th centuries). The analytical study of crucibles from different contexts in Europe and America employed optical microscopy and SEM–EDS, coupled with archaeological and historical data. We identified two major producers of crucibles, both of them in Central Europe, whose products appear widely distributed internationally. The analytical data allow an explanation of the technical reasons behind their superior reputation, as both crucible types shared comparable material properties, such as thermal, chemical and mechanical stability. Conversely, the two crucible types were radically different in their manufacture and appearance. We argue that, besides technical considerations, sensorial aspects such as texture and colour may have played an important role in the perception and choice of materials.     

MECHANICAL PERFORMANCE OF QUARTZ-TEMPERED CERAMICS: PART I,STRENGTH AND TOUGHNESS*

The effect of quartz temper on the physical and mechanical properties of clay ceramics and the elucidation of the underlying mechanisms that are responsible for these effects are presented here. Characteristics studied included bulk density, open and closed porosity, density of impervious portion and fracture morphology. Mechanical behaviour was studied by measuring energy dissipation during fracture, Young's modulus, initial fracture toughness and strength in flexure. The significant increase in toughness with quartz volume fraction is explained by the development of a model that accounts for the crack distribution around the grains. The archaeological implications of the work are discussed on the basis of all the parameters that might affect the potter's choices of raw materials.     

ON FUTURES AND ENDINGS: NARRATOLOGICAL REFLECTIONS ON CONTEMPORARY FORMS OF CRISES*

The article examines the changing relationship of the present to the future from a narratological perspective. It argues that three dominant narrative schemas structure the contemporary experiences of temporality in the Western social imaginary: the modern crisis narrative, the apocalyptic narrative, and the chronic crisis narrative. In its first part, the article shows how the modern sense of crisis, which emerged in the late eighteenth century, sedimented into a powerful narrative template by knitting together the past, the present, and the future into a unified plot. The second part focuses on the resurgence of apocalyptic stories in the Western social imaginary and humanities discourse. The final part highlights the special contribution of aesthetics of precariousness to the Western imaginary of time and temporality. It argues that the “chronic crisis narrative” deflates the teleological narrative arc of the modern crisis paradigm while also shunning the end-time discourse of the apocalyptic narrative.     

AN EXPLORATION OF PREHISTORIC SPINNING TECHNOLOGY: SPINNING EFFICIENCY AND TECHNOLOGY TRANSITION*

Thigh‐spinning and spindle‐spinning, methods for making yarn and string, have been used through the millennia to produce substantial quantities of yarn for textiles. Productivity data were gathered in a replication study of thigh‐spun and spindle‐spun yarns and were recompiled from the literature. Calculated production rates allow comparison of the spinning methods. Factors influencing production rate include intrinsic fibre properties, fibre preparation and particular details of spinning technique, as well as the experience and motivation of the spinner. The role of efficiency in technology transition between thigh‐spinning and spindle‐spinning is discussed.     

EVAPORITES OF THE WADI NATRUN: SEASONAL AND ANNUAL VARIATION AND ITS IMPLICATION FOR ANCIENT EXPLOITATION*

The evaporitic deposits of the Wadi Natrun on the edge of the Western Desert of Egypt have been used in variety of crafts and industries for over 6000 years. This paper reviews the formation processes of the evaporitic deposits between the different lakes in the wadi and for the wadi as a whole. It shows that the precipitation of sodium carbonate minerals within the lakes is seasonal and probably subject to long‐term fluctuation as climate varies. This has a significant impact on the use of the lakes for ancient industries, particularly the manufacture of glass.     

1. NARRATIVE FORM AND HISTORICAL SENSATION: ON SAUL FRIEDLÄNDER'S THE YEARS OF EXTERMINATION1

Saul Friedländer's magnum opus, The Years of Extermination, has been received worldwide as an exemplary work of history. Yet it was written by a historian who in the last two decades has strenuously asserted the limits of Holocaust representation. At the center of this essay is a problem of historical writing: how to write a historical narrative of the Holocaust that both offers explanations of the unfolding events and also suggests that the most powerful sensation about those events, at the time and since, is that they are beyond words. I explore Friedländer's crafting of such a narrative by considering, first, the role of his attempt in The Years of Extermination to explain the Holocaust and, second, the narrative form of the book. The book is best seen, I argue, not primarily as a work of explanation but as a vast narrative that places an explanation of the Holocaust within a specific form of describing that goes beyond the boundaries of the historical discipline as it is usually practiced. This form of describing goes beyond the almost positivist attachment to facts that dominates current Holocaust historiography. By using Jewish individual testimonies that are interspersed in the chronological history of the extermination, Friedländer creates a narrative based on ruptures and breaks, devices we associate with works of fiction, and that historians do not usually use. The result is an arresting narrative, which I interpret by using Johan Huizinga's notion of historical sensation. Friedländer sees this narrative form as specific to the Holocaust. I view this commingling of irreducible reality and the possibility of art as a required sensibility that belongs to all historical understanding. And in this respect, The Years of Extermination only lays bare more clearly in the case of the Holocaust what is an essential element in all historical reconstruction.     

CAVES AND GEOPHYSICS: AN APPROXIMATION TO THE UNDERWORLD OF TEOTIHUACAN,MEXICO*

This article describes the result of a geophysical survey in the vicinity of the most important construction of the ancient Prehispanic urban centre of Teotihuacan, Mexico. The survey was intended to locate a system of tunnels under the city. It is proposed that the system was originally dug to obtain construction materials, but afterwards it was used for ideological needs.     

X-RAY MICROANALYSIS OF ANCIENT GLASSY MATERIALS: A COMPARATIVE STUDY OF WAVELENGTH DISPERSIVE AND ENERGY DISPERSIVE TECHNIQUES*

Sensitivity, precision and accuracy of quantitative microanalysis of major, minor and trace elements present in ancient glasses by energy dispersive spectrometry (EDS) is compared to that by wavelength dispersive spectrometry (WDS). Although there are certain problems with EDS due to peak overlaps and background noise, the precision and minimum detection limits of EDS for most of the important elements in ancient glasses were found to compare favourably to those of WDS. Both EDS and WDS, when quantified by comparison to glass standards, can produce reliable results which are adequate for most technological questions.     

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 IMPACT OF SOLUBLE SALTS ON THE DETERIORATION OF PHARAONIC AND COPTIC WALL PAINTINGS AT AL QURNA,EGYPT: MINERALOGY AND CHEMISTRY*

The wall paintings of Al Qurna in Egypt were studied by means of XRD and ICP–AES in order to determine their mineralogical and chemical composition, and to evaluate the impact of soluble salts on their deterioration, including the identification of the building materials and pigments used. Soluble salts analysis showed that NaCl is the most common soluble salt in the bedrock, ground water and surface water samples. The building materials are affected by the ground water, while the wall paintings in the area are affected by the Upper Egypt climatic conditions, which were studied in order to detect their role in the deterioration cycle in the area.