Optically Stimulated Luminescence

Ground penetrating radar (GPR) and the single-aliquot regenerative-dose (SAR) was used to determine the depositional environments and age of the Merritt Island sand
ridge sequence. Five direct-push cores and ten OSL ages were collected. A new model of cosmic dose rate calculation, which removes the much younger aeolian cap, was utilized for the first time and helped produce more consistent OSL ages. Based on our data and samples, the Merritt Island sand ridges are a classic beach ridge set that was deposited during the MIS-5c sea-level highstand. This is supported by the results of Osmond (1970) based on U/Th ages and Burdette et al. (2009) based on OSL ages of a coquinoid limestone west of the beach ridge sequence.

This article analyses and dates the construction
of Holy Cross church at Hattula in Finland.
The study is based on building-archaeological
observations that were recorded and processed
when analysing rectified photographs of each
facade in a CAD environment. In addition, totalstation
measurements, laser scanning and multiimage
photogrammetry were also used. Dating
was carried out using Optically Stimulated Luminescence
(OSL), among other methods.
The survey reveals that the church was probably
planned and built as a single project from
the foundations to roof height. Analysis of the
bonding (mostly monk bond) shows the church
was built by seven masons in eleven phases,
each comprising sub-phases of usually four
or eight courses. At least 121 000 bricks were
needed to build the double-thickness shell wall
(two stretchers abreast on each side), and three
types of scaffolding were used for the project.
Sometimes Flemish bond was used, probably for
technical reasons. Given that the same group of
masons built the entire church, the work would
have been completed in a relatively short time.
The building process, including brick manufacture,
would have taken four to five seasons. The
results of the OSL dating (five samples) show
that the church was probably built in the second
half of the 15th century or beginning of the 16th
century.

Keywords: Brick, buildings archaeology, mason, Middle Ages, monk bond,
optically stimulated luminescence

Archaeological surveys of the Negev Highlands show that the settlement history of this arid environment oscillated widely over time. This observation is almost entirely based on scant sherd assemblages from surveys, with only a few chronometric ages from one or two archaeological features at a given site. The reasons for the scarcity of chronometric ages include insufficient attention to radiocarbon dating in past research, low amounts of datable organic material for radiocarbon dating and issues related to low rate of site accumulation, and incomplete preservation of activity remains. In order to overcome these problems, we present here the results of a detailed chronometric radiocarbon and optically stimulated lumines-cence (OSL) dating study exploring the development of Negev archaeological sites in the third millennium BCE. The study included micromorphological analyses to aid identification of sedimentological and post-depositional processes at the studied sites. At Nahal Boqer 66, one of many small Negev third millennium BCE sites, seven radiocarbon ages were determined from archaeological contexts that suggest repeated discontinuous activity throughout the Early Bronze (EB) and early part of the Intermediate Bronze Age (IBA) (c. 3300-2350 BCE). At Ein Ziq- one of a few large sites in the region- seven samples were dated; they show a very short period of activity in the beginning of the IBA (c. 2450-2200 BCE). OSL age determinations at this site provided evidence for the rapidity of site burial by sediment accumulation. Also, OSL ages from secure depositional contexts verified- via micromorphology- are in agreement with those obtained by radiocarbon dating. Taken together, the results provide new systematic evidence for the timing of EB-IBA activity in the arid Negev Highlands.

Geophysical survey in 2006, part of the Silbury Hill Conservation Project, revealed extensive settlement in two fields south of Silbury Hill. The Later Silbury project consisted of an archaeological evaluation in 2010 and reassessment of surviving material from earlier excavations in the immediate area. The project aimed to characterise the Romano-British settlement, and to elucidate this poorly understood phase of activity around the monument and within the Stonehenge and Avebury World Heritage Site, contributing to future management and presentation. Roman Silbury was probably a roadside settlement or small town along the London to Bath road (the modern A4). Immediately south of the road, any surviving features were masked in the magnetic survey by pipelines. In the arable field sloping down to the Kennet, the surveys indicated an extensive settlement, including a minor road or trackway running south from the road with three large subdivided rectangular enclosures to its west. Five evaluation trenches were opened here, concentrating on one of the enclosures and avoiding the large stone buildings identified by ground penetrating radar. Three trenches were opened in the water meadow to investigate geophysical anomalies and alluvial deposits near the river. This report assesses the results of the 2010 evaluation.

Stimulated luminescence of novel La 2 O 3 nanophosphors doped with Dy 3+ and Eu 3+ and co-activated with Li + , prepared by microwave-assisted solution combustion synthesis, was investigated for the very first time. X-ray diffraction results indicated hexagonal La 2 O 3 crystalline phase. Lanthanide and Li + doping did not affect the La 2 O 3 crystal structure. Scanning electron microscopy images showed nanoparticle morphologies such as plates, rods and irregular shapes. Photoluminescence spectra of La 2 O 3 :Dy 3+ , Li + exhibited blue and green emission bands due to Dy 3+ transitions. For La 2 O 3 :Eu 3+ , Li + , sharp emission lines, corresponding to the optical transitions of Eu 3+ were observed. Thermoluminescence glow curve of La 2 O 3 :Dy 3+ , Li + previously exposed to beta radiation exhibited a prominent glow peak located at ∼46 °C, possibly useful for after-glow or persistent lu-minescence applications, whereas La 2 O 3 :Eu 3+ , Li + curve, displayed three intense peaks at ∼50, ∼110 and ∼150 °C. Thermoluminescent signal repeatability and decay curve asymptotic behaviour could place La 2 O 3 :Eu 3+ , Li + as suitable for medium and high-dose radiation dosimetry applications.

Geoarchaeological investigations along the Galana River, eastern Kenya, document a pattern of channel aggradation and then degradation from the Middle to Late Holocene. Archaeological occupations at six sites in fluvial terraces along a ˜100 km stretch of the Galana River in Tsavo East National Park correspond with fluvial aggradation beginning ca. 6000 years ago. Artifact analyses indicate that the inhabitants of these sites utilized ceramics and stone tools similar to Pastoral Neolithic traditions detected at other penecontemporaneous archaeological sites in East Africa and possessed domesticated cattle from ca. 3700 years ago. The site occupations that occur during this period have dense artifact concentrations of predominantly locally procured items. The Galana River incised after ca. 900 years ago and there is a noticeable paucity of archaeological material, reflecting more peripatetic lifestyles. This shift in settlement pattern may reflect a decrease in reliance on riverine food sources during the Late Holocene, with diminished riparian environments associated with channel incision.

Roman metal use and related extraction activities resulted in heavy metal pollution and contamination, in particular of Pb near ancient mines and harbors, as well as producing a global atmospheric impact. New evidence from ancient Gerasa (Jerash), Jordan, suggests that small-scale but intense Roman, Byzantine and Umayyad period urban, artisanal, and everyday site activities contributed to substantial heavy metal contamination of the city and its hinterland wadi, even though no metal mining took place and hardly any lead water pipes were used. Distribution of heavy metal contaminants, especially Pb, observed in the urban soils and sediments within this ancient city and its hinterland wadi resulted from aeolian, fluvial, cultural and post-depositional processes. These represent the contamination pathways of an ancient city-hinterland setting and reflect long-term anthropogenic legacies at local and regional scales beginning in the Roman period. Thus, urban use and re-use of heavy metal sources should be factored into understanding historical global-scale contaminant distributions.

Recent archaeological research in Australia’s north-eastern Kimberley has luminescence dated a large red sedimentary feature, known as Minjiwarra, with artefacts in stratified contexts from the late Holocene to ∼50,000 years ago. This site is located on the Drysdale River, with preliminary excavations undertaken as part of an ARC Linkage Project. Deeply stratified sites in association with rockshelters are uncommon across the NE Kimberley and basal dates at open cultural deposits vary greatly. Most of them are mid-Holocene in age. However, Minjiwarra appears to cover the entire span of potential human occupation in this region, with associated lithic technology, reported on here.

[GAL] Preséntanse os resultados dun estudo realizado nos restos da Porta Real que se conservaban dentro dunha ventá arqueolóxica situada nunha praza delimitada polas rúas Santiago, polo N, María Barbeito, polo NW, e Paseo Dársena polo SW e S na cidade de A Coruña, con motivo da súa limpeza realizada no ano 2015 por parte da empresa Tomos Restauración Conservación S.L., dentro dun proceso xeral de reurbanización do Parque da Marina e Praza do Parrote nesa cidade. A intervención consistiu na lectura estratigráfica de paramentos, na comparación das técnicas construtivas empregadas coas documentadas con outros paramentos conservados noutras zonas do recinto defensivo de A Coruña, na análise da planimetría histórica da zona e na caracterización e datación dos diferentes morteiros preservados nos restos da Porta Real mediante Luminiscencia Opticamente Estimulada (OSL). O obxectivo final era establecer a secuencia construtiva e datación dos restos identificados como Porta Real. Este texto correspóndese co informe final presentado no seu momento.

[EN] The results of a study carried out on the remains of the Puerta Real (A Coruña) are presented. These were preserved inside an archaeological window, located in a square bounded by the streets Santiago, to the N, María Barbecho, to the NW, and Paseo Dársena to the SW and S in the city of A Coruña. The study was part of the cleaning work carried out in 2015 by Tomos Restauración Conservación S.L., as part of the general process of redevelopment of the Parque de la Marina and Plaza del Parrote in that city. The intervention consisted of the stratigraphic reading of the walls, the comparison of the construction techniques with those documented with other walls in other areas of the defensive walls of A Coruña, the analysis of the historical planimetry of the area and the characterisation and dating of the different mortars preserved using Optically Stimulated Luminescence (OSL). The final objective was to establish the construction sequence and dating of the remains identified as Puerta Real. This text corresponds to the final report presented at the time.

The objective of this work was to develop a new optically stimulated luminescence (OSL) material for dosimetry applications that is tissue equivalent and has high sensitivity to ionizing radiation, fast lumi-nescence lifetime, and intrinsic neutron sensitivity. To achieve this combination of properties, we started with a host material with low effective atomic number, MgB 4 O 7 (Z eff ¼ 8.2) , with an appropriate dopant characterized by short luminescence lifetime (Ce 3 þ). The samples were synthesized using Solution Combustion Synthesis with excess boric acid to achieve the correct crystallographic phase and Li co-doping to enhance its sensitivity. We investigated the thermoluminescence (TL) and OSL properties as a function of annealing temperature, radiation dose, dopant concentration, and time elapsed after irradiation (i.e., signal fading). We also applied a step-annealing procedure to investigate the depth of the trapping centers associated with the OSL signal. The samples obtained are characterized by a dominant TL peak at $ 210 °C with intensity comparable to LiF:Mg,Ti. The OSL intensity is $ 50% of that from Al 2 O 3 :C when using Hoya U-340 filters and shows no saturation up to almost 1 kGy. The OSL signal seems to originate from trapping center with stability 4 150 °C, which means that the OSL fading is expected to be small. After the first day, in which fading associated with shallow traps is observed, fading of the total OSL signal was o4% within 6 days. The possibility of enhancing the neutron sensitivity was also demonstrated by synthesizing the material with enriched 10 B. Although further development and characterization of the material may be needed, this work demonstrates that this host/dopant combination can be a viable alternative in OSL do-simetry, particularly for 2D dose mapping and neutron dosimetry applications.

Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include a light-safe sample and material for dose-rate determination. The accuracy and precision of luminescence dating results are directly related to the type and quality of the material sampled and sample collection methods in the field. Selection of target material for dating should include considerations of adequacy of resetting of the luminescence signal (optical and thermal bleaching), the ability to characterize the radioactive environment surrounding the sample (dose rate), and the lack of evidence for post-depositional mixing (bioturbation in soils and sediment). Sample strategies for collection of samples from sedimentary settings and fired materials are discussed. This paper should be used as a guide for luminescence sampling and is meant to provide essential background information on how to properly collect samples and on the types of materials suitable for luminescence dating. La datación por luminiscencia proporciona una estimación directa de la edad del último momento en el que el cuarzo o los minerales de feldespato se expusieron a la luz o al calor y que se ha aplicado exitosamente a depósitos, superficies rocosas y materiales expuestos al fuego en distintos contextos arqueológicos y geológicos. Las estrategias de muestreo son diversas y pueden ser individualizadas dependiendo de las circunstancias locales, aunque todas las muestras de sedimentos deben incluir una muestra segura que no haya sido expuesta a la luz y material para calcular la tasa de la dosis. La exactitud y precisión de los resultados de la datación por luminiscencia están directamente relacionadas con el tipo y la calidad de los materiales muestreados y los métodos de recolección de muestras en el campo. La elección del material de estudio para su datación debe incluir las siguientes consideraciones en torno a la idoneidad de poder reposicionar la señal de luminiscencia (blanqueador óptico y térmico), la capacidad de caracterizar el ambiente radiactivo que rodea la muestra (la tasa de la dosis) y el que no exista evidencia de una alteración posdeposicional (bioperturbación en suelos y sedimentos). Se discuten las estrategias de muestreo para la recolección de muestras de contextos sedimentarios y de materiales expuestos al fuego. Este artículo debe utilizarse como una guía para el muestreo por luminiscencia y tiene la intención de proveer información básica de cómo recolectar muestras y sobre los tipos de materiales apropiados para la datación por luminiscencia.

The site of Mwanganda's Village, located along a paleochannel in northern Malawi, is one of only a few sites that have characterized the Middle Stone Age (MSA) of Malawi for decades (Clark & Haynes, 1970; Clark et al., 1970; Kaufulu, 1990). The Malawi Earlier-Middle Stone Age Project has re-examined the site using new mapping and chronometric tools in order to reinterpret the site's significance within the context of current debates surrounding human origins and the potential role the environment played in shaping human behavior. The new data do not support the previous hypothesis that the site was an elephant butchery location (contra Clark & Haynes, 1970; Clark et al., 1970; Kaufulu, 1990). Instead, the evidence shows successive colonization of riparian corridors by MSA hunter-gatherers focused on exploiting localized resources during periods of generally humid climates while other lakes desiccated across Africa. We challenge the hypothesis that stable and intermediately high lake levels within the African Rift Valley System (sensu Trauth et al., 2010) catalyzed the evolution of regional interaction networks between 42 and 22 ka. Instead, we interpret the evidence to suggest that regional variants of technology persist into the late MSA as foragers focused on exploiting resources from local catchments.

The non-destructive nature of X-ray fluorescence (XRF) spectrometers is a principal reason for an increase in their use in archaeological science over the last 15 years, especially for analysing museum-curated artefacts and in situ site fabrics. Here, we show that low power XRF spectrometry can be detrimental for luminescence dating (surface applications such as mud-wasp nest dating in particular). We investigated the effects of irradiation by X-rays emitted from handheld and benchtop spectrometers on optically stimulated luminescence (OSL) signals. Measurements were taken using a portable OSL (pOSL) unit on the following unprepared archaeological materials: sedimentary quartz grains, pottery, a mud-wasp nest, stone tools and a rock flake with anthropogenically applied pigment and natural pigmentation (iron oxides). We observed an increase in luminescence compared to initial background counts for all materials tested, which could lead to overestimation of age determinations in some situations. Our experiment provides a reminder of the potential effects of X-ray radiation, and the need for thorough documentation of all recording and analytical techniques applied to archaeological materials.

The direct dating investigation of rock art remains a deficit issue yet the surface luminescence dating of rock surfaces initiated in the 90's has made some considerable progress. The luminescence dating of lithic surfaces inheres a dual mechanism regarding bleaching / growth of luminescent signal by depth and exposure time. The present overview reconfirms the suggestion that rock surfaces contain a record of exposure and burial history and that these events can be quantified. The physical mechanisms in trapping / de-trapping of electron traps, under different conditions of sun exposure and burial, the mathematical modeling of experimental and simulated data (modified double exponential and cumulative log-norm) and some World examples are briefly reviewed.

For the first time, electron spin resonance optical dating (ESROD) has been conducted on littorally transported and aeolian siliciclastic sediments in Florida. ESROD utilizes light-sensitive radiation-sensitive defects at silicon sites that have been replaced by aluminum and titanium atoms to give rise to a timedependant signal. These defects saturate at higher levels of radiation dose, compared to optically stimulated luminescence, and therefore extend the optical dating range back into the millions of years. Our results show that the Trail Ridge Sequence is a multi-depositional unit that began deposition around 2.2 Ma and continued until 6 ka. The Osceola Cape, of the Effingham Sequence, was deposited around 1.5 Ma, and the Chatham Sequence was a multi-depositional terrace with at least three events preserved.

Lake Mungo, presently a dry lake in the semi-arid zone of southeastern Australia, preserves a unique record of human settlement and past environmental change within the transverse lunette that built up on its downwind margin. The lunette is >30 km long and the variable morphology along its length suggests spatial variability in deposition over time. Consequently this presents differential potential for the preservation of past activity traces of different ages along the lunette. Earlier work at Lake Mungo focused primarily on the southern section of the lunette, where two ritual burials of considerable antiquity were found. Here we describe the depositional history of the central section of the Lake Mungo lunette, together with the first single grain optically stimulated luminescence (OSL) chronology of the full stratigraphic sequence and of three hearths. We thereby lay the foundation for systematic investigation of the distribution of archaeological traces through the sedimentary record.

Dating terraces, the most prominent feature of the agricultural landscape in many parts of the world, is a problem for archaeologists. This study presents an interdisciplinary approach that combines archaeological survey and excavations with direct sediment dating of terrace fill using Optically Stimulated Luminescence (OSL). The study focuses on Ramat Rahel, a multi-period site located in the southern outskirts of modern Jerusalem, Israel, where, on a defined terraced slope chosen for a small-scale landscape archaeology project, three main phases of terrace construction and use were identified. The earliest phase dates to the Late Byzantine/Early Islamic period, the second to medieval times, and the last to the Ottoman period. The results enable a comprehensive reconstruction of the changing local landscape through time and demonstrate the validity of OSL, when combined with archaeological investigations, as a reliable method for terrace dating.

The use of lithium fluoride (LiF) crystals and films as imaging detectors for EUV and soft-X-ray radiation is discussed. The EUV or soft-x-ray radiation can generate stable color centers, emitting in the visible spectral range an intense fluorescence from the exposed areas. The high dynamic response of the material to the received dose and the atomic scale of the color centers make this detector extremely interesting for imaging at a spatial resolution which can be much smaller than the light wavelength. Experimental results of contact microscopy imaging of test meshes demonstrate a resolution of the order of 400 nm. This high spatial resolution has been obtained in a wide field of view, up to several mm^2. Images obtained on different biological samples, as well as an investigation of a soft x-ray laser beam are presented. The behavior of the generated color centers density as a function of the deposited X-ray dose and the advantages of this new diagnostic technique for both coherent and non coherent EUV sources, compared with CCDs detectors, photographic films and photo-resists are discussed.

Factors affecting the random and systematic error in calibrating three sets of 100 LiF:Mg,Ti thermoluminescent detector chips were investigated. The chips were held in a polymethyl methacrylate plate with 0.3 cm deep wells covered with a thin top plate, affixed to a polymethyl methacrylate phantom 150 cm from a 3.2 × 1010 GBq 137Cs source, used to irradiate the chips to 4.52 mGy. Three sets of chips were used: one new, one heavily used, and one having relatively high degrees of visible physical damage. Variations in the exposure rate across the plate were measured with an ion chamber. Experimental drift was judged by performing successive calibrations on subsequent days, while always reading the chips in the same order. The chips were subject to manual examination to determine variations in mass and physical quality. This study indicates that more accurate calibrations can be obtained by accounting for the error caused by nonuniformity in the delivered dose, which was in this study as high as 4.4% from the center to the edges of the target. Making use of more than three calibrations only reduces the standard deviation as a percentage of the mean of a set by less than 1%. Desirable dosimeters in commercially rejected sets were identified by comparing each dosimeter's standard deviation of response across all calibrations to a commercially acceptable control set. Up to 50% variations in mass and visual quality, including opacity, fracture, and surface scratches to chips, showed little to no correlation with their response.