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.     

ON THE AGE AND CONTENT OF JAR‐35—A SEALED AND INTACT STORAGE JAR FOUND ON THE SOUTHERN PLATEAU OF QUMRAN*

An intact and sealed storage jar known as Jar‐35 was found in 2004, south of the Qumran settlement. A previous study identified tartrate in the deposit of the jar, indicating the possible past presence of wine ( Buti et al. 2006 ). However, we cannot confirm this finding. Using liquid and gas chromatography with mass spectrometric detection, no trace of tartaric acid or salts thereof could be detected in our samples. We show that the major component of the deposit is gypsum. No other organic compounds were identified with the methods that we have applied. Both radiocarbon dating of charcoal in the deposit and thermoluminescence dating of the ceramic jar show that it dates to the main period of habitation at Qumran (c. 100 bc to ad 70).     

CONSTRUCTING CARIBBEAN CHRONOLOGIES: COMPARATIVE RADIOCARBON DATING OF SHELL AND WOOD ARTEFACTS FROM PRE‐COLUMBIAN SITES IN CUBA

The lack of robust chronological frameworks for pre‐Columbian archaeology in the Caribbean limits the interpretive potential of ongoing studies of inter‐site and inter‐island interaction. This paper reviews the dating of 28 wood and shell artefacts from sites in northern Cuba in an attempt to date pre‐Columbian activity in the region and develop dating methodologies for the study of pre‐Columbian interaction in the Caribbean. This research compares dates from wood and shell artefacts from the waterlogged site of Los Buchillones in north‐central Cuba with dates from shell artefacts from sites on eight islands in the Sabana–Camaguey archipelago in the Bahama Channel. In addition to providing a chronological framework based on absolute dates for pre‐Columbian activity in northern Cuba, this paper also considers the methodological issues of using shell for dating pre‐Columbian activity in the Caribbean.     

NEW RADIOCARBON ACCELERATOR DATES ON ARTEFACTS FROM THE EARLY MESOLITHIC SITE OF STAR CARR,NORTH YORKSHIRE*

For the well‐known early Mesolithic site of Star Carr, dating of organic artefacts by accelerator mass spectrometry (AMS) has been hampered by treatment of bone and antler recovered during the original excavations with preservatives. Some, untreated, artefacts were, however, collected after Clark's excavation in 1950. Four of these artefacts were AMS dated in 1995, but two of the dates were significantly younger than the others, and were questionable due to their low collagen yields. These suspect samples have now been re‐analysed, demonstrating that all four artefacts are of similar date. The significance of these dates for the chronology of Star Carr is discussed.     

K/AR DATING AS A MEANS OF SOURCING LEVANTINE EPIPALAEOLITHIC BASALT IMPLEMENTS

Through K/Ar dating of basalt implements from two Mount Carmel late Epipalaeolithic sites and samples of locally occurring basalts, it was possible to demonstrate clearly that the prehistoric inhabitants of these sites did not utilize the locally available Upper Cretaceous (88–77 My) basalts. The dates of the basalt implements are of Tertiary-Quaternary age (3.7-<0.250 My) which suggests the exploitation of basalt exposures at least 60 km east of the sites. This is the first direct evidence for long-distance exchange/trade of an essential raw material in the Levant as early as 13000 BP.     

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.     

ISSUES RELATED TO DETERMINING BURIAL CHRONOLOGY BY FLUORIDE ANALYSIS OF BONE FROM THE MAYA ARCHAEOLOGICAL SITE OF CHAU HIIX,BELIZE*

Fluoride percentage of bone is often used to determine relative dates of burials in archaeological contexts. An analysis of prehistoric Maya burials at Chau Hiix, Belize, identifies taphonomic factors, including soil composition, grave depth, soil disturbance, age at death and cortical bone thickness, that cause variations in the rate of fluoride absorption by altering the access of water to bone. This example demonstrates that fluoride dating is unlikely to be useful at most prehistoric Maya sites because of the inconsistent taphonomy due to typically diverse mortuary practices, and it also serves as a cautionary tale for applications of this methodology in other contexts.     

URANIUM‐SERIES AND LUMINESCENCE DATING OF VOLCANIC LITHIC ARTEFACTS*

U‐series dating was used to determine the growth rate of a feldspar‐to‐clay weathering rind in a mid‐Holocene Cascade–Olcott tradition andesite core, and luminescence dating (last exposure to sunlight) was used to date fine‐grained feldspars scraped from the surfaces of similar buried artefacts from a ¹⁴C‐sediment‐dated archaeological site (45KI464) on the wet western slope of the Cascade Mountains of Washington. For U‐series dating, we measured ²²⁶Ra excess (²²⁶Ra excess =²²⁶Ra –²³⁰Th) in five stratigraphic depth controlled rind scrapings. ²³⁸U, ²³²Th and ²³⁰Th were counted by alpha spectrometry, and ²²⁶Ra and ²¹⁰Pb were counted by gamma spectrometry on each sub‐sample.     

THE RADIOCARBON CHRONOLOGY OF KOPIA,AN EARLY GLASS MANUFACTURING CENTRE IN INDIA

Right from the time of the Painted Grey Ware (PGW) culture, dating to c. 1200–600 bce , more than 210 archaeological sites in India have provided evidence of glass, but there has been no attempt to date the glass‐yielding layers by radiometric techniques. This has hampered the establishment of a chronology for the beginning and evolution of glass‐making in India. The site of Kopia was excavated by the first author for three seasons from 2004 to 2006 to understand the history, development and technology of glass production in India. The excavation produced evidence of a long period of occupation, covering the Fine Grey Ware (FGW), Northern Black Polished Ware (NBP), Sunga–Kushana and Gupta periods. Twenty accelerator mass spectrometry (AMS) and radiocarbon dates, all derived from charcoal samples and processed independently by three laboratories, are available from the site. The dates range in their calibrated form on average from the ninth to the second century bce in locality I and from the second century bce to the second century ad in locality II.     

Bear dentine aspartic acid racemization analysis: a proxy for the dating of Pleistocene cave infills

A high correlation between chronometric determinations based on aspartic acid racemization ratios and radioactive dating methods is described from samples of cave bear (Ursus deningeri and Ursus spelaeus) dentine. For samples from a very restrictive environment, as deep cave bear sites are (in view of their highly stable geochemical and thermal history), an age calculation algorithm was obtained. It has been found that there is a very close relationship between collagen preservation, from total aspartic acid in the > 3500 D fraction, and the amino acid racemization.     

The Potential for Dating the Old Scatness Site,Shetland, By Optically Stimulated Luminescence

A series of deposits from the agricultural infield of the multiperiod settlement mound, Old Scatness, were investigated for their potential to yield optically stimulated luminescence dates. Luminescence properties of quartz grains were found to vary through the sequence, but dates were successfully obtained from five deposits, including anthropogenic soils, windblown sands and sands within midden deposits. Single‐aliquot equivalent dose measurement was found to be the most appropriate method for dating the deposits. The OSL dates obtained accorded well with the dates provided by archaeological evidence and included the post‐medieval, Iron Age, Bronze Age and Neolithic periods of Shetland, while a substantial midden was dated to the Bronze/Iron Age transition.     

DATING OF THE HOMINID (HOMO NEANDERTHALENSIS) REMAINS ACCUMULATION FROM EL SIDRÓN CAVE (PILOÑA,ASTURIAS, NORTH SPAIN): AN EXAMPLE OF A MULTI‐METHODOLOGICAL APPROACH TO THE DATING OF UPPER PLEISTOCENE SITES

The age of Neanderthal remains and associated sediments from El Sidrón cave has been obtained through different dating methods (¹⁴CAMS, U/TH, OSL, ESR and AAR) and samples (charcoal debris, bone, tooth dentine, stalagmitic flowstone, carbonate‐rich sediments, sedimentary quartz grains, tooth enamel and land snail shells). Detrital Th contamination rendered Th/U dating analyses of flowstone unreliable. Recent ¹⁴C contamination produced spurious age‐values from charcoal samples as well as from inadequately pretreated tooth samples. Most consistent ¹⁴C dates are grouped into two series: one between 35 and 40 ka and the other between 48 and 49 ka. Most ESR and AAR samples yielded concordant ages, ranging between 39 and 45 ka; OSL dating results permitted adequate bracketing of the sedimentary layer that contained the human remains. Our results emphasize the value of multi‐dating approaches for the establishment of reliable chronologies of human remains.     

DATING ANCIENT LIME MORTARS BY GEOCHEMICAL AND MINERALOGICAL ANALYSIS

This paper proposes a method of dating based on the study of the mineralogy and geochemistry of lime mortars. If the mortars used in constructing the various parts of a building are made from limestones of distinct geochemistry (minor elements) and mineralogy (clay content), such differences should be identifiable in their compositions. Furthermore, if some parts of the building can be reliably dated, the mortars used in their construction can be compared with mortars taken from parts of the building whose dates are unknown. Under certain conditions, a relationship can be established between the mortars, and a date may be proposed. An experimental procedure, based on identification of mortar phases, is proposed. The method was tested on two historical monuments, built in the eleventh to twelfth and nineteenth centuries respectively, which illustrate different dating problems.     

RADIOCARBON DATES FROM THE OXFORD AMS SYSTEM: ARCHAEOMETRY DATELIST 34

This is the thirty‐fourth list of AMS radiocarbon determinations measured at the Oxford Radiocarbon Accelerator Unit (ORAU). Amongst the dates obtained for archaeological sites included here are the latest series of determinations from the key sites of Proskynas (Greece), Kova?evo (Bulgaria) and Khirbet Qeiyafa (Israel), as well as others dating to the Palaeolithic, Mesolithic and later periods. Submitters of the material provide comments on the significance of the results.     

SIMS‐SS,A NEW OBSIDIAN HYDRATION DATING METHOD: ANALYSIS AND THEORETICAL PRINCIPLES*

The water diffusion mechanism in obsidian has been revisited with the advent of a new dating approach employing secondary ion mass spectrometry (SIMS). The water diffusion SIMS(+) profile and the concept of a surface saturation (SS) layer in obsidians both provide a sound basis for the new diffusion age equation (SIMS‐SS) and are supported by dated world examples ( Liritzis et al. 2004 ). Here, we present the basic physical–chemical analysis of the mass transport phenomenon on which the new dating method is based. The crucial age parameter of the SIMS‐SS dating approach for archaeological obsidians—that is, the surface saturation (SS) layer—is supported by both theoretical and experimental data.     

OPTICAL DATING OF GRANITIC STONE SURFACES*

A novel luminescence methodology for dating surfaces of granitoid rocks is presented, with encouraging results for archaeological stone structures. It is based on the zeroing of the latent signal of optically stimulated luminescence (OSL) in feldspar and quartz grains of the stone surface during exposure to daylight. When after bleaching the surface is shielded from light, the OSL signal builds up again, such that its intensity provides an age for the event of the last exposure to light. This event could be the construction or the destruction of stone structures or, for example, sedimentary deposition of granitic boulders, such as in fan deposits. The experimental approach utilizes a high spatial resolution detection technique (HR‐OSL) for OSL of minerals that are left in their original petrological context; that is, without any mineral separation. With this approach, steep gradients in microdosimetry at the surface and at grain boundaries become important and are discussed in detail. The new dating technique is successfully applied to a stone wall of the medieval castle of Lindenfels in southwestern Germany and the pre‐Columbian Nasca lines (geoglyphs) around Palpa in southern Peru.     

RESEARCH REPORT: MAGNETIC INVESTIGATIONS AND THE AGE OF A MEDIEVAL KILN AT KUNGAHÄLLA (SOUTH‐WEST SWEDEN)*

The results from a magnetic survey and archaeomagnetic investigation of a medieval brick kiln at Kungahälla in Bohuslän (south‐west Sweden) are reported. Detailed magnetic total field and magnetic gradient measurements over known traces of the kiln showed marked local magnetic anomalies of up to 200 nT, revealing the rectangular shape of the kiln remains. Palaeomagnetic investigations of the remanent magnetization of 12 bricks from the kiln floor gave precise definitions of both the direction of the archaeomagnetic field [(D_m, I_m) = (66.7°, 8.8°), k = 655, α₉₅= 1.7°] and the palaeointensity [B_m= 69.0 ± 3.6 µT]. An archaeomagnetic date is obtained by comparing the direction of the archaeomagnetic field found in the kiln with a geocentral dipole‐transformation of the British master‐curve for secular variation. Of two possible archaeomagnetic dates (ad 1280 ± 50 or ad 1480 ± 50), the ad 1280 ± 50 age is in good accordance with the C‐14 ages and archaeological dates as well as with direct historical evidence, whereas a c. 100 years younger TL date appears to be too young.     

A NEW DIRECT RADIOCARBON AMS DATE FOR AN UPPER PALAEOLITHIC HUMAN BONE FROM SIBERIA

A new AMS radiocarbon date has been obtained from a Siberian human bone sample taken directly from a cranial fragment. The specimen comes from the north‐east Siberian site of Pokrovka 2 (55⁰19′46.30″N, 92⁰26′48.80″E). The remains consist of the anterior portion of the cranium or the superior part of the face; that is, the forehead and the roof of the eye sockets. Sadly, indifferent features of the frontal bone do not allow a confident diagnosis of the sex of the individual. The evidence suggests, however, that the remains are probably those of a young adult (teenager) and an anatomically modern human, rather than a Neanderthal. Radiocarbon dating was undertaken at the Oxford Radiocarbon Accelerator Unit (ORAU). The radiocarbon age determination of the bone fragment, 27 740 ± 150 bp (OxA‐19850), is one of the earliest direct dates for a modern human from Siberia. The Pokrovka cranial fragment dates to the middle Upper Palaeolithic of Eurasia and is broadly contemporary with the human remains from the famous eastern European site of Sunghir. When the radiocarbon age is compared with the Cariaco Basin ¹⁴C data set and the Greenland oxygen isotope record of NGRIP, it corresponds with Greenland Interstadial 5, a warmer phase of the Last Glacial period, although this is a preliminary conclusion, and is based on climate records that may or may not be wholly synchronous between the two locations.     

A NEW THERMOLUMINESCENCE DATING TECHNIQUE FOR HEATED FLINT*

A new thermoluminescence (TL) technique for determining the age of heated flint artefacts from archaeological sites is presented. It is a variant of the SAR protocol, which is usually used for OSL dating of sediment, but it is not based on a presumed model for fitting the dose–response curve. Dose recovery tests as well as comparisons with standard protocols show the accuracy of the new technique. It is found that the sensitivity of the thermoluminescence (TL) signal of flint in the orange–red waveband does not show severe changes due to the heating process while measuring the TL. This allows the application of a short SAR procedure, which requires only two dose points. The technique does not require as much instrument time as other SAR techniques, and thus is advantageous for dating very old samples. The major advantage of this new technique is the small amount of sample material required, which allows the dating of samples that are too small for standard TL dating techniques.