METHODOLOGICAL DEVELOPMENTS IN THE LUMINESCENCE DATING OF BRICK FROM ENGLISH LATE‐MEDIEVAL AND POST‐MEDIEVAL BUILDINGS*

Fired clay brick samples, obtained from a group of seven high‐status late‐medieval and post‐medieval buildings in England ranging in age from c. ad 1390 to 1740, were dated by the luminescence method using an optically stimulated luminescence (OSL) technique. The results obtained indicate that, when applied to quartz extracted from brick, the technique is capable of producing dates that are in consistently good agreement with independent dating evidence for the buildings. For six samples taken from a group of four dating ‘control’ buildings the mean difference between the central values of luminescence and assigned ages was 5 ± 10 years (SD, n = 6). The methodology used is appropriate for application to other standing buildings in other temporal and geographic regions, and may be used with confidence where conventional dating methods are less certain. The study also examines the luminescence characteristics of quartz and the characteristics of the lithogenic radionuclides in brick samples and identifies various aspects related to the assessment of experimental uncertainty in testing the reliability of the method.     

GEOCHEMICAL CHARACTERIZATION OF ARCHAEOLOGICAL LIME MORTARS: PROVENANCE INPUTS*

Chemical and mineralogical analyses were carried out on historical lime mortars from the parish church of Santa María La Real (Guipúzcoa). The study included various periods ranging from Roman to modern times and allowed the identification of various types of raw materials. In order to obtain pure binder, free of carbonate aggregates and charcoal particles, an innovative binder separation method was implemented. The chemical composition of the binder allows discrimination of different provenance areas for the raw materials, although those areas do not correlate with specific historical periods. In addition, the influence of burial processes on the primeval chemical features has been assessed and reveals that modern mortars display greater chemical modification than the Roman mortars.     

NEW ARCHAEOMAGNETIC STUDIES NEAR XI'AN,CHINA*

Archaeomagnetic and mineral magnetic studies were made of known-age samples from fired structures and sediments from archaeological sites near Xi'an, China. The fired materials retained a stable record of the direction of the past geomagnetic field, which compared well with previous investigations and could contribute to an archaeomagnetic calibration curve. However, discrepancies with documented observations of the field were noted.     

PETROGRAPHY AND PROVENANCE INTERPRETATION OF THE STONE MOULDS FOR BRONZE DAGGERS FROM THE GALDONG PREHISTORIC SITE, REPUBLIC OF KOREA*

This paper presents material characteristics and raw material provenance of the stone moulds for bronze slender daggers from Galdong. This type of bronze dagger is uniquely distributed in the Korean Peninsula and these stone moulds were the first to be found by excavation. The stone moulds were made of igneous hornblendite with course-grained holocrystalline textures. Based on petrological, mineralogical and geochemical characteristics, the original rock materials of the moulds were inferred to be derived from the Jangsu or Namwon areas which are about 50 km away from the excavation site. It is a notable achievement that this provenance study confirmed the domestic production of Korean-styled daggers.     

ASSESSING NATURAL CLAY COMPOSITION IN THE VALLEY OF OAXACA AS A BASIS FOR CERAMIC PROVENANCE STUDIES

The Oaxaca Clay Survey was initiated to provide baseline data on clay composition within the Valley of Oaxaca, Mexico, to assist in provenance determination of prehistoric ceramics. Natural clays were sampled from 135 locations throughout the valley, and analysed using INAA in combination with ceramic petrography. Observed geographical trends in trace‐element and mineralogical composition confirm that while parent material (surficial geology) strongly affects clay composition, a continuum of variation exists within the valley. The study develops and tests a continuous spatial model of clay composition that provides greater resolution in ceramic sourcing than bedrock alone. By establishing a regional framework for Oaxaca Valley clays, the survey will support significant advances in our understanding of pottery production and exchange within the valley, and provide a more robust means for monitoring exchange between the valley and neighbouring regions.     

PROCESSING CLAY FOR POTTERY IN NORTHERN CAMEROON: SOCIAL AND TECHNICAL REQUIREMENTS*

For several decades, interpreting technical variations in the physical characteristics of pottery has followed two major trends: the ‘cultural’approach and the ‘behavioural or ‘techno‐functionalist’approach. Using data collected during extensive ethnographic fieldwork, I will consider the relative importance of social and technical requirements in the field of clay processing techniques in the Faro area (northern Cameroon) 1 will show that environmental and techno‐functional constraints cannot explain technical variations, while cultural factors appear determinant. However, faking the discussion one step further, I will show the complexity of the social/cultural mechanism involved in the regional distribution of these techniques.     

EFFECTS OF MILLING: A POSSIBLE FACTOR INFLUENCING THE DURABILITY OF HISTORICAL MORTARS

In their literary texts, some classical Roman authors such as Gaius Plinius Secundus and Marcus Vitruvius Pollio stress the importance of milling when preparing mortars. Following these indications, this work describes the effects of milling between lime (calcium hydroxide) and clay brick powder before and after the addition of water. Starting and resulting materials were investigated by XRPD, SEM/EDS, differential scanning calorimetry and thermogravimetry (DSC/TC), colorimetry, densimetry and porosimetry. Prolonged milling changes the mineralogy of the starting materials and increases their reactivity. The final lime pastes, starting from materials milled for varying periods of time, had different mineralogical and physical characteristics. These results may help to clarify the reasons for the marked differences in durability of some historical mortars.     

CLAY RESOURCES AND TECHNICAL CHOICES FOR NEOLITHIC POTTERY (CHALAIN,JURA, FRANCE): CHEMICAL,MINERALOGICAL AND GRAIN‐SIZE ANALYSES*

Many authors have considered pottery manufacturing constraints and sociocultural elements as factors in change in past civilizations over time. The main issue of this research is to better understand the reasons for changes, or choices, in pottery raw materials. The very precise and detailed stratigraphy and cultural succession of occupations is based on dendrochronological data from the lake‐dwelling sites of Chalain (Jura, France). Petrographic, palaeontological and chemical analyses were used to determine the nature and origins of the raw materials used by the Neolithic potters. Stratigraphy and dendrochronological data were used to reconstruct in detail the evolution dynamics of fabric changes. Several raw material sources were identified for many of the pottery groups. Each of them was sampled for qualitative experimental tests of pottery forming. The experimental results show a high variability between the sediments tested. This variability was quantitatively estimated by XRF, XRD, the Rietveld method, calcium carbonate quantification and laser grain‐size analyses of matrices, indirect measures of plasticity. These analytical results allow a better understanding of the differences observed in the experimental tests. On the basis of these experimental and analytical results, changing parameters such as pottery manufacturing constraints, mineralogical characteristics of raw materials and sociocultural factors are considered. In conclusion, all the social and technical parameters, in each archaeological context, must be taken into account for a better understanding of the changes occurring throughout the chronological sequence.     

THE GEOCHEMISTRY OF THE MAJOR SOURCES OF ARCHAEOLOGICAL OBSIDIAN ON HOKKAIDO ISLAND (JAPAN): SHIRATAKI AND OKETO

The geochemical compositions for obsidian from two of the most important sources on the Japanese island of Hokkaido, Shirataki and Oketo, are presented. This work represents the first systematic study of obsidian geochemistry on Hokkaido from the view of modern methodological standards. The study was performed with the help of neutron activation analysis to determine the concentrations for 28 elements. The results obtained allow us to subdivide both sources into two geochemical groups (Shirataki‐A and ‐B; and Oketo‐A and ‐B), with each representing an individual sub‐source. Obsidian from both Shirataki and Oketo sources is identified at archaeological sites located on Hokkaido, on the neighbouring Sakhalin Island and Kurile Islands, and in the lower course of the Amur River basin. The distance of obsidian transport during the Upper Palaeolithic was up to ～250 km, and in the following Neolithic and Palaeometal periods up to ～1200 km. This testifies to the wide distribution of Hokkaido obsidian to archaeological complexes in North‐East Asia and its active transport/exchange in prehistory. The data presented here should be used as a reference for the obsidian geochemistry of Shirataki and Oketo sources from now on.     

THE CHEMICAL COMPOSITION OF SOME ARCHAEOLOGICALLY SIGNIFICANT FLINT FROM DENMARK AND SWEDEN

Flint was one of the most widely employed raw materials for artefact manufacture in Denmark and Sweden during the Stone Age, and it continued to be used during subsequent periods. Prehistoric flint mining and lithic manufacturing studies in these countries have attracted considerable attention, but there have been no recent attempts to chemically characterize the geological source materials. This paper builds on a pilot study ( Hughes et al. 2010 ) and uses energy‐dispersive X‐ray fluorescence (EDXRF) analysis to determine quantitative composition estimates for nine major, minor and certain trace elements in seven archaeologically significant flint sources in Denmark and Sweden, along with new data on a number of other sources of prehistoric significance. These data provide a geochemical foundation for ongoing research devoted to determining contrasts and continuities in the time and space utilization of flint sources in Scandinavian prehistory.