DIRECT GAMMA-RAY SPECTROMETRIC DATING OF FOSSIL BONES: PRELIMINARY RESULTS

A non-destructive gamma-ray spectrometry was used for direct dating of fossil animal and human bones taken from an alluvial Quaternary site in northern Italy. The ages were obtained using the U-Pa method: the chronological results are in agreement with palaeofaunal indicators and taphonomic data. The ages of two samples showed concordance with the U-Th method; in a third case good agreement was also found with the radiocarbon date, thus lending credence to our modified gamma spectrometric method.     

AN ATTEMPT AT DATING THE SWANSCOMBE SKULL BONES USING NON-DESTRUCTIVE GAMMA-RAY COUNTING

A low-background germanium spectrometer was used to measure the gamma-ray spectra of the three parts of the Swanscombe skull. Detailed studies of the method showed that it was possible to make accurate measurements of the content of ²²⁶ Ra and ²³¹ Pa but less accurate ones of ²³⁸U and ²³⁵U. Results from the three samples were inconsistent, showing that their exposure to radioactive ground water must have been very different, although they were found close together. The uncertainty in the ratio of ²³⁴U to ²³⁸U in the ground water and the lack of knowledge of the time at which the bones acquired the uranium also prevented the deduction of any reliable dates for these specimens.     

THE PETRALONA HOMINID SITE: URANIUM-SERIES RE-ANALYSIS OF ‘LAYER 10’CALCITE AND ASSSOCIATED PALAEOMAGNETIC ANALYSES

Separate sublayers of the ‘layer 10’calcite from the Mausoleum of Petralona Cave, Greece, have been re-analysed by Uranium-series and palaeomagnetic methods. The results confirm earlier findings that the whole of layer 10 represents a long time span, from about 160 ka to more than 350 ka, the latter being the dating limit of the U-series method using alpha-spectrometry. The minimum age refers to the upper brown sublayer that is now believed to correspond directly to the brown calcite that cemented the hominid skull to the adjacent cave wall; there was too little of the skull calcite to date directly by alpha-spectrometry. The age shifts caused by making corrections for the amount of detritus in the sublayer are effectively insensitive to assumed initial values of the amount of common ²³⁰Th present. Consequently, the minimum age estimate for the skull is about 160 ka, in approximate agreement with several earlier estimates. Palaeomagnetic analyses of ‘layer 10’and underlying sedimentary layers showed that the magnetization is unstable and cannot be used as a basis for age control in the Mausoleum.     

URANIUM-SERIES DATING OF BONES AND TEETH FROM CHINESE PALAEOLITHIC SITES

The reliability of uranium-series dating of fossil bones and teeth is studied. On this basis the first absolute chronology for about 20 important Chinese palaeolithic sites is proposed. A two-stage model for open-system samples is discussed.     

THE DESIGN OF EVALUATION OF ASSAYS OF TRACE ELEMENTS IN A FOSSIL BONE*

The flame atomic absorption spectroscopy method of analysis of trace elements (Mn, Sr, and Cu) in a mammoth's bone and the method of estimation of the data using regression analysis are described. The concentration fields of the single elements in a cross-section through the bone are well described by a fourth degree polynomial. The minimum values and their coordinates have been determined. A method of determination of the original concentrations of trace elements in fossil bones is described further. The approximating features of the regression exponential equations and of the diffusion functions of various shapes were determined and a method for calculating the concentrations and diffusion properties of the bones once deposited in the soil is suggested. The original trace element concentration can be estimated by extrapolation of a suitable exponential or diffusion function.     

FACTORS AFFECTING THE VIABILITY OF THERMOLUMINESCENCE DATING OF GLASS

The aim of this study is to achieve a better understanding of some of the factors that limit the thermoluminescence (TL) dating of glass. Using a‘model system’(lithium-disilicate samples having different levels of crystallinity from 0 to 100%), we show, first, that the TL of glass is reproducible only if the glass is not heated above its temperature glass transition and second, that there is a clear connection between the TL sensitivity and the degree of crvstallinity of the sample. We conclude that thermoluminescence is not a general dating method for archaeological glass, but it can be applied to particular glass samples that haue specified characteristics.     

THERMOLUMINESCENCE DATING OF A CRUCIBLE FRAGMENT FROM AN EARLY TIN PROCESSING SITE IN TURKEY

Archaeological exploration in the Taurus mountains at Göltepe in south-central Turkey has uncovered a site indicating the presence of extensive tin ore mining and smelling operations The most recent find of smelting crucible fragments allowed for a thermoluminescence-hased age determination spanning a late fifth to early third millennium BC date. This result is consistent with a number of radiocarbon dates derived for charcoal also found at the site. The importance of this site relates to the possible tin production and subsequent trade with southwestern Asia which would have provided this otherwise scarce ingredient to bronze technology in that area. This date is directly for crucible material and thus confirms the antiquity of tin smelting at Göltepe.     

LUMINESCENCE DATING OF POTTERY FROM LATER PREHISTORIC BRITAIN*

Dating of later prehistoric settlements relies heavily on potter; typologies in England and yet there has been little scientific dating in order to verify these typologies. In this work, luminescence dating techniques were applied directly to the pottery which forms the typological framework. Excellent agreement was obtained between the luminescence ages, and archaeological age ranges for known‐age pottery sherds with diagnostic form and surface decoration. A lower correlation, however, was found in several regions between the luminescence ages for undecorated body sherds and the archaeological assessment which was necessarily based solely on fabric, suggesting the need for reassessment of these fabric chronologies.     

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.     

CHARACTERIZATION AND THERMOLUMINESCENCE DATING OF PREHISTORIC POTTERY SHERDS FROM MILENA

This paper reports the results obtained applying absolute dating methodologies and mineralogical, petrographical and micropalaeontological characterization techniques to prehistoric pottery sherds varying in age from the Sicilian Middle Neolithic to Bronze Age. All samples came from the archaeological area of Milena (Caltanissetta, Sicily); those of the Bronze Age were found on a site with a precise stratigraphic succession. The investigation has contributed to the determination of an absolute chronology for the Milena prehistoric period. The data provide, for the first time in Sicily, absolute dates covering a wide spectrum of cultures following one another in the same area and, for the Bronze Age site, correlated to the precise stratigraphic succession. The petrographical and mineralogical analyses allowed not only the identification of the principal constituents of the pottery, but also the formulation of some hypotheses regarding the specific manufacturing techniques of different epochs. The microfacies, obtained from the presence of fossils in the groundmass of the pottery, were also analysed and compared with the microfauna present in the Miocene clays outcropping in the area. The data identified local Messinian clay as the raw material probably used in the manufacture of the pottery and also support the presence, already assumed by archaeologists, of imported Mycenaean pottery, thus supporting the dates obtained on pottery taken from the same stratum.     

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.     

INFRARED STIMULATED LUMINESCENCE DATING OF ARCHAEOSEDIMENTS

In this study the feasibility of infrared stimulated luminescence (IRSL) for dating loessic colluvial sediments, deposited as a result of human activity, is investigated. It is demonstrated that the ‘IRSL-clock’is reset after a few minutes of daylight exposure even under foggy weather conditions. Samples of independently known age were taken at the Neolithic Bruchsal Aue site in south-west Germany. Different laboratory procedures are tried and a method is suggested (narrow wave-length band in the blue, preheat at 220° C for 5 min) to overcome age underestimates. This laboratory technique yielded archaeologically reasonable ages for colluvial sediments and hollow fillings. The IRSL-ages demonstrate that the deposition of the colluvia is related to soil erosion triggered by human activities, such as wood clearing and agriculture. The successful dating of archaeosediments has a great potential for applications in environmental archaeology as well as in geomorphology and in particular for the reconstruction of man-landscape interactions in central Europe.     

AUTOMATION OF SOLUBILITY PROFILES USING A FLOW CELL

The solubility profile technique is a means of characterizing the mineral phase of bones and fossils from archaeological and palaeontological sites. The method is based on the differential dissolution of variously substituted apatites in acetate buffer at pH 4.5. The original solubility profile protocol, which involves repetitive washing and centrifuging, is extremely cumbersome and time-consuming. Here we describe an alternative, automatic method in which the fossil bone preparations are dissolved in a perspex cell. The behaviour of fossil preparations in the manual and automatic protocols are compared. We conclude that the dissolution cell is satisfactory for routine applications, but that the original, manual protocol is preferable for preliminary investigation of untested assemblages.     

ONLY TIME WILL TELL: A REVIEW OF THE METHODOLOGY OF DIRECT ROCK ART DATING

Epistemology has not kept pace with the progress experienced in the direct dating of rock art. This paper reviews the experimental methods that have been developed in recent years. While many do provide important information about the possible age of rock art, it is of concern that the precipitate archaeological interpretations these data are used for are often not warranted. Some are attributable to not understanding the severe qualifications that apply to most dating results, others perhaps to over-enthusiasm on the part of some researchers. The introduction of archaeological dynamics into direct dating of rock art threatens the reliability of this young methodology. Some of the pitfalls are considered in this paper, and a general rationale for the direct dating of rock art is developed.     

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.     

LASER ARGON DATING AND GEOLOGICAL PROVENANCING OF A STONE AXE FROM THE STONEHENGE ENVIRONS*

The recently-developed laser microprobe ⁴⁰argon-³⁹ argon technique has been used to give a geological date for a rhyolitic tuff stone axe fragment from the Stonehenge environs. The method requires only milligramme-sized samples and gives dates of sufficient accuracy to aid in provenancing artefacts to sources, as well as information on the heating history of samples. The axe sample is of Lower Carboniferous date (341 ± 5 Ma) and this limits possible sources to outcrops within the Scottish Midland Valley and small altered exposures in Dartmoor. X-ray fluorescence analysis of the axe suggests the Scottish Midland Valley as the more likely source. The laser argon analysis also shows that the implement had not been heated in antiquity. Laser argon-argon dating can, therefore, be a useful tool in artefact study.     

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.     

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.