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.     

OPTICAL DATING OF SINGLE AND MULTIPLE GRAINS OF QUARTZ FROM JINMIUM ROCK SHELTER,NORTHERN AUSTRALIA: PART II,RESULTS AND IMPLICATIONS*

Quartz sediments from the floor deposit at Jinmium rock shelter have been investigated using the multiple-grain and single-grain optical dating methods described by Galbraith et al. (1999, this volume). Here we present the results of this dating programme and argue that the artefact-bearing sediments were deposited within the last 10000 years. This time interval is consistent with the radiocarbon chronology but is much younger than previous claims for initial human occupation during the Pleistocene. Analysis of individual grains revealed also that the characteristic saturation doses of some grains are unusually high, which may permit dating of deposits older than a few hundred thousand years. Such grain-to-grain differences raise doubts, however, about the validity of using multiple-grain samples to investigate the phenomenology of quartz luminescence.     

DATA ON 61 CHEMICAL ELEMENTS FOR THE CHARACTERIZATION OF THREE MAJOR GLASS COMPOSITIONS IN LATE ANTIQUITY AND THE MIDDLE AGES

Sets of 20 soda ash, 16 soda lime and 23 wood ash glasses mainly from excavations in Europe were analysed by microprobe and LA–ICP‐MS for 61 elements and are presented as average concentrations with standard deviations. Concentrations of sodium, potassium and magnesium allow the major glass type to be identified. Specific compositions of the raw materials of glass production indicate certain sources, technical processes and ages. Heavy minerals etc. of quartz sands contain rare earth elements (REE) from crustal fractionations that are different for the three major glass types. Accumulations of P, B, Ba, Mn and K in wood from soils by organic processes can characterize glass from certain regions.     

IDENTIFYING AND CLASSIFYING VEIN QUARTZ ARTEFACTS: AN EXPERIMENT CONDUCTED AT THE WORLD ARCHAEOLOGICAL CONGRESS, 2008

Worldwide, vein quartz was used as a raw material for stone tools, and in many regions quartz was the dominant raw material, if not the only raw material. While using quartz was not necessarily problematic for the communities in question, and was often preferred over other materials, the ‘problem’ with quartz is for archaeologists attempting to analyse the material, especially with coarse‐grained quartz. This paper presents the results of a quartz recognition experiment conducted on volunteer participants at the 2008 World Archaeological Congress (WAC) conference held in Dublin, Ireland. The results have shown that the identification and classification of vein quartz artefacts is particularly challenging, even for analysts with substantial experience in quartz artefact analysis.     

METHODS OF ENGRAVING MESOPOTAMIAN QUARTZ CYLINDER SEALS

Cylinder seals, which were produced more or less continuously for about 3000 years in Western Asia, were worked with designs in intaglio. In this paper we report the results of an investigation into the techniques used to engrave seals composed of quartz. Our observations were made with a binocular microscope and supplemented by examination of impressions with a scanning electron microscope. A range of factors was considered, including shape in plan, topography, surface texture and orientation of features. In this way four basic techniques of engraving have been recognized. They have been tentatively interpreted as micro-chipping, filing, wheel-cutting and drilling.     

METHODS OF ENGRAVING MESOPOTAMIAN CYLINDER SEALS: EXPERIMENTAL CONFIRMATION*

Previous observations of the intaglios on quartz cylinder seals from Western Asia suggested that they had been engraved by one or more of four basic techniques, that is, micro-chipping, filing, drilling and wheel-cutting. In this paper we test our earlier observations and interpretations experimentally. Examination and comparison of experimentally engraved features with the seal intaglios was made directly with a binocular microscope and also by examination of impressions with a scanning electron microscope. Successful replication was achieved using tools of flint, chalcedony, copper, bronze and iron together with quartz and emery abrasives.     

LUMINESCENCE DATING OF SEDIMENTS—THE DETECTION OF HIGH EQUIVALENT DOSE GRAINS USING AN IMAGING PHOTON DETECTOR*

In this paper we describe quantitative measurements on the thermoluminescence of many single grains, made with an imaging photon detector. In several of the sediments examined a few bright grains were found which had a high equivalent dose (ED). Physical measurements made on these grains using binocular microscopy and analytical scanning microscopy enabled several possible explanations for the causes of the high ED grains to be rejected. Insufficient bleaching at deposition or the intrusion of grains from an older sediment were identified as the most probable explanation for these grains.     

OPTICAL DATING RESULTS FOR BRITISH ARCHAEOLOGICAL SEDIMENTS

In this paper optical dating results for a range of British archaeological sediments are presented to illustrate the potential this method offers for archaeologists. The optical dating is shown to offer an absolute method for directly dating the deposition of sediments for an age range of approximately 1–300ka. Problems have been found with recuperation of the optically stimulated luminescence signal and insufficient bleaching at deposition of the sediment. A suitable correction method for the recuperation has been found and a method of identifying insufficient bleaching is suggested.