New developments in the scientific dating of brick.

Fired clay brick has been widely used in the construction of buildings in many parts of Europe since its introduction by the Romans, and the extremely robust physical properties of fired clay enable bricks to endure within the archaeological record for many centuries, notably as structural elements in standing buildings. Most ancient standing buildings, erected wholly or partially in brick, have undergone alterations since their original construction and consequently usually have a complex history. The current approaches to unravelling building histories have the capability to date the original construction and subsequent alterations to within several years or better where structural analysis combined with searches for documentary evidence and tree-ring dating of timbers is employed. However, for many vernacular buildings, difficulties in dating may arise where documentary evidence has not survived, or may have never existed, where tree-ring dates are not available (such as the replacement of original structural timbers, insufficient number of rings, etc.), and where there is an absence of diagnostic architectural features. In these circumstances the margin of uncertainty in dating may increase by at least several decades, depending on the nature of the available building evidence. This paper discusses the potential of a scientific dating method, luminescence dating, that provides a means of determining the date of manufacture of fired clay brick. Although the luminescence method has become well established in the field of archaeology, it has had limited application to building history. This paper provides a brief introduction to the application of the method and its potential for further development in historic buildings analysis, drawing upon the results of a recent test programme of dating brick from late-medieval and post-medieval English buildings

The Durham TL ceramic dating service

A TL dating service for archaeologists has been established at our laboratory and its viability is being investigated as part of a research project. The service has been structured to cater for the needs of British archaeologists, although we consider that the fundamental approach would be appropriate to most TL dating requirements. Two levels of accuracy are offered in survey dating and dating programmes as part of a two tiered system. In its first year of operation the laboratory has tested over 80 samples and in this paper we discuss the structure of the service and the dates produced

Spatially-resolved measurement of optically stimulated luminescence and time-resolved luminescence

Spatially-resolved measurements of optically stimulated luminescence (OSL) were performed using a two-dimensional scanning system designed for use with planar samples. The scanning system employs a focused laser beam to stimulate a selected area of the sample, which is moved under the beam by a motorised stage. Exposure of the sample is controlled by an electronic shutter. Mapping of the distribution of OSL using a continuous wave laser source was obtained with sub-millimeter resolution for samples of sliced brick, synthetic single crystal quartz, concrete and dental ceramic. These revealed sporadic emission in the case of brick or concrete and significant spatial variation of emission for quartz and dental ceramic slices. Determinations of absorbed dose were performed for quartz grains within a slice of modern brick. Reconfiguration of the scanner with a pulsed laser source enabled quartz and feldspathic minerals within a ceramic sample to be differentiated using a single stimulation wavelength by measuring the time-resolved luminescence spectrum

Extending the range of optically stimulated luminescence using vein quartz and quartzite sedimentary pebbles

The feasibility of applying optically stimulated luminescence (OSL) techniques to obtain estimates of the burial age of lithic clasts in the form of pebbles of quartzose lithology is investigated in this study. We applied OSL measurement procedures to vein-quartz and quartzite pebbles from contexts at five sites with fluvial and coastal beach contexts of depositional age ranging from 500 ka to the mid Holocene. As in previous OSL studies with lithics, measured depth-dose profiles were interpreted to identify regions associated with key stages in the burial history of the pebbles, including the extent of pre-burial optical resetting, primary burial and any subsequent secondary stages of exposure to sunlight. While some of the pebbles had not been fully optically reset before burial, none were in field saturation, as commonly encountered with larger lithic clasts such as cobbles. The relatively low concentrations of radionuclides within vein-quartz and quartzite pebbles simplified the assessment of the radiation dose rate. OSL age estimates consistent with independent dating evidence were obtained for the three sites sampled in the UK (Langford Quarry, Leet Hill Quarry, Swanscombe Skull Site and Barnfield Pit) and one of two sites tested in Portugal (Forte Cão), whereas evidence of secondary optical bleaching detected in pebbles from a second site (Vale de Atela) underestimated the independent age for primary burial. The oldest depositional age of the contexts tested was ∼500 ka (Leet Hill Quarry), and for some of the pebbles tested there was the capacity to extend the potential dating range further as the age equivalence of the limiting value of De was in excess of 1 Ma. The advantages of working with smaller, portable, clasts in the form of pebbles and with a lithology of higher transparency opens up a wide range of potential applications, whether the depositional processes are environmental or anthropogenic in origin or modification

Recovering a lost seismic disaster. The destruction of El Castillejo and the discovery of the earliest historic earthquake affecting the Granada region (Spain)

This paper discusses recent archaeological fieldwork conducted at El Castillejo, a medieval Islamic settlement in Los Guájares, Granada, southern Spain. Results from combined archaeological excavation and archaeoseismological assessment of standing structures suggest that the site was affected by a destructive earthquake during its occupation. Radiocarbon samples and OSL analysis point to a seismic event in the period CE 1224–1266. The earthquake occurred within an area marked by a ‘seismological gap’ in terms of historic seismicity and the causative fault has been tentatively identified in the Nigüelas-Padul Fault System which lies north of the settlement. This event is not recorded by national or European seismic catalogues and represents the oldest historic earthquake in the Granada area. Our work stresses the significant impact that targeted archaeological investigations can generate in our understanding of the local historic seismicity, thus providing clear implications for seismic disaster prevention and reduction

Luminescence dating of sediment mounds: associated with shaft and gallery irrigation systems

Optically stimulated luminescence (OSL) techniques, supported by geomorphological analysis, have been applied to date the construction of shaft and gallery irrigation systems, more commonly referred to as qanats, falaj and foggara. The approach developed was tested on four hydraulic systems located in semi-arid landscape settings, three in Murcia, Spain, and the fourth in the Sus Tekna region, Morocco. Excavation of the characteristic sediment mounds that surround each ventilation shaft enabled a detailed examination of strata containing upcast deposits and their assignment to the main stages in the construction and use of the hydraulic feature. OSL techniques with single grain resolution applied to samples taken from the key strata provided age estimates for their deposition on the mound and, from these, dating of the construction and use of the system. Of the four irrigation systems analysed, the OSL dates indicated that the youngest had been constructed in the 19th century AD and the oldest, located in Murcia, was dated to the Roman period. The latter is of archaeological significance because the introduction of this particular form of hydraulic technology to Spain is widely identified as an Islamic innovation of the early 8th century AD

Wase baksteen gedateerd. Natuurwetenschappelijk dateringsonderzoek in de Sint-Andreas- en Sint-Gislenuskerk in Belsele (Sint-Niklaas)

De nauwkeurige datering van middeleeuwse gebouwen is vaak problematisch. Gedateerde geschreven bronnen over de bouwgeschiedenis zijn niet voorhanden of vatbaar voor diverse interpretaties. Vormelijke kenmerken staan niet altijd garant voor een nauwkeurige en gefundeerde datering. Ook bouwmaterialen en constructietechnieken kunnen soms niet meer bieden dan grove chronologische aanwijzingen. Sinds enkele decennia wordt in toenemende mate gebruik gemaakt van natuurwetenschappelijke technieken voor de absolute datering van middeleeuwse gebouwen. In dit onderzoek werd de parochiekerk Sint-Andreas- en Sint-Gislenus in Belsele (Sint-Niklaas) onderworpen aan verschillende natuurwetenschappelijke dateringstechnieken, zoals onder meer 14C-datering, thermoluminescentie (TL), optisch gestimuleerde luminescentie (OSL) en archeomagnetische analyse (AM). Het onderzoek focuste op de in baksteen gebouwde lichtbeuk van het middenschip en de bijbehorende dakkap, traditioneel gedateerd in het tweede kwart van de 13de eeuw. Voor Vlaanderen alvast een unieke en waardevolle gevalstudie

Older Veteran Digital Disparities: Examining the Potential for Solutions Within Social Networks

BACKGROUND: Older adults typically have less access to the Internet than other age groups, and older Veterans may use the Internet even less due to economic and geographic reasons. OBJECTIVE: To explore solutions to this problem, our study examined older Veterans\u27 reported ability to access technology through their close social ties. METHODS: Data were collected via mail survey from a sample of Veterans aged 65 years and older (N=266). RESULTS: Nearly half (44.0%, 117/266) of the sample reported having no Internet access. Yet, among those without current access, older Veterans reported having a median of 5 (IQR 7) close social ties with home Internet access. These older Veterans also reported that they would feel comfortable asking a median of 2 (IQR 4) social ties for help to access the Internet, and that a median of 2 (IQR 4) social ties would directly access the Internet for the older Veteran to help with health management. CONCLUSIONS: Findings suggest that even older Veterans without current Internet access have at least two social ties with home Internet who could be called upon for technology support. Thus, older Veterans may be willing to call upon these surrogate seekers for technology assistance and support in health management. This has implications for the digital divide, technology design, and health care policy