57 research outputs found
Technical note: Darkroom lighting for luminescence dating laboratory
An optimal lighting setting for the darkroom laboratory is fundamental for the accuracy of luminescence dating results. Here, we present the lighting setting implemented in the new Luminescence Dating Research Laboratory at Stony Brook University, USA. In this study, we performed spectral measurements on different light sources and filters. Then, we measured the optically stimulated luminescence (OSL) signal of quartz and the infrared stimulated luminescence (IRSL) at 50 °C (IR50) as well as post-IR IRSL at 290 °C (pIRIR290) signal of potassium (K)-rich feldspar samples exposed to various light sources and durations. Our ambient lighting is provided by ceiling fixtures, each equipped with a single orange light-emitted diode (LED). In addition, our task-oriented lighting, mounted below each wall-mounted cabinet and inside the fume hoods, is equipped with a dimmable orange LED stripline. The ambient lighting, delivering 0.4 lux at the sample position, induced a loss of less than 5 % (on average) in the quartz OSL dose after 24 h of exposure, and up to 5 % (on average) in the IR50 dose for the K-rich feldspar samples, with no measurable effect on their pIRIR290 dose. The fume hood lighting, delivering 1.1 lux at the sample position, induced a dose loss of less than 5 % in quartz OSL and K-rich feldspar IR50 doses after 24 h of exposure, with no measurable effect on their pIRIR290 dose. As light exposure during sample preparation is usually less than 24 h, we conclude that our lighting setting is suitable for luminescence dating darkrooms, it is simple, inexpensive to build, and durable.</p
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New Neanderthal remains associated with the âflower burialâ at Shanidar Cave
Shanidar Cave in Iraqi Kurdistan became an iconic Palaeolithic site following Ralph Solecki's mid twentieth-century discovery of Neanderthal remains. Solecki argued that some of these individuals had died in rockfalls andâcontroversiallyâthat others were interred with formal burial rites, including one with flowers. Recent excavations have revealed the articulated upper body of an adult Neanderthal located close to the âflower burialâ locationâthe first articulated Neanderthal discovered in over 25 years. Stratigraphic evidence suggests that the individual was intentionally buried. This new find offers the rare opportunity to investigate Neanderthal mortuary practices utilising modern archaeological techniques.Leverhulme Trust (Research Grant RPG-2013-105), the Rust Family Foundation, the British Academy, the Wenner-Gren Foundation, the Society of Antiquaries, the McDonald Institute of Archaeological Research at the University of Cambridge and the Natural Environment Research Councilâs Oxford Radiocarbon Dating Facility (grant NF/2016/2/14). The ongoing dating program is supported by the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement number 324139 âPalaeoChronâ awarded to Professor Tom Higham, University of Oxfor
Infrared Radiofluorescence (IR-RF) of K-Feldspar:An Interlaboratory Comparison
Infrared Radiofluorescence (IR-RF) is a relatively new method for dosimetric dating of the depositional timing of sediments. This contribution presents an interlaboratory comparison of IR-RF measurements of sedimentary feldspar from eight laboratories. A comparison of the variability of instrumental background, bleaching, saturation, and initial rise behaviour of the IR-RF signal was carried out. Two endmember samples, a naturally bleached modern dune sand sample with a zero dose and a naturally saturated sample from a Triassic sandstone (~250 Ma), were used for this interlaboratory comparison. The major findings of this study are that (1) the observed IR-RF signal keeps decreasing beyond 4000 Gy, (2) the saturated sample gives an apparent palaeodose of 1265 ± 329 Gy and (3) in most cases, the natural IR-RF signal of the modern analogue sample (resulting from natural bleaching) is higher than the signal from laboratory-induced bleaching of 6 h, using a solar simulator (SLS). In other words, the laboratory sample bleaching was unable to achieve the level of natural bleaching. The results of the investigations are discussed in detail, along with possible explanations
Infrared radiofluorescence (IR-RF) dating:A review
International audienceLuminescence dating methods on natural minerals such as quartz and feldspars are indispensable for establishing chronologies in Quaternary Science. Commonly applied sediment dating methods are optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). In 1999, Trautmann et al. (1999a, b) proposed a new related technique called infrared radiofluorescence (IR-RF). IR-RF denotes the infrared luminescence signal of feldspar resulting from exposure to ionizing radiation and potentially offers a significant methodological advance compared to OSL and IRSL regarding luminescence signal stability, dating range and required measurement time. The method has rarely been applied due to a lack of commercially available measurement equipment but experienced a revival during the last years. The present article provides a state-of-the-art overview of the physical background of IR-RF, its challenges, applications and the potential as a dating method. The paper particularly addresses practical considerations for applying IR-RF dating, including signal bleachability and saturation behaviour, and summarizes proposed solutions
Feldspars as support for the luminescence dating of archaeological deposits and quaternary sequences of Aquitaine
Les donnĂ©es chronologiques disponibles pour les gisements du PalĂ©olithique moyen du Sud-Ouest de la France font Ă©tat dâun manque de jalons chronologiques fiables. Pour ces pĂ©riodes anciennes, lâĂ©tablissement dâun cadre chronologique nĂ©cessite un investissement mĂ©thodologique important dans le domaine de la datation numĂ©rique. Les rĂ©sultats obtenus dans cette Ă©tude reposent essentiellement sur la datation par luminescence optique de grains de feldspaths et de quartz contenus dans les sĂ©diments. En particulier, lâĂ©tude des signaux de luminescence classiquement exploitĂ©s (IRSL, pIR-IRSL), nous permet de mieux Ă©valuer la fiabilitĂ© des datations Ă partir des feldspaths potassiques. Un protocole de datation fondĂ© sur lâexploitation du signal de radioluminescence (IR-RF) de ces minĂ©raux a aussi Ă©tĂ© dĂ©veloppĂ©. Ainsi, la luminescence optique a Ă©tĂ© appliquĂ©e Ă des Ă©chantillons provenant de six gisements de rĂ©fĂ©rence : Les Pradelles (Marillac, Charente), Combe Brune 2 (Creysse, Dordogne), Roc de Marsal (Campagne, Dordogne), Artenac (Saint-Mary, Charente), La Quina (Gardes-le-Pontaroux, Charente) et La Ferrassie (Savignac-de-Miremont, Dordogne). La combinaison des rĂ©sultats obtenus nous a permis, au sein de chaque niveau archĂ©ologique, dâĂ©valuer la pertinence des datations et de proposer pour chaque gisement un scĂ©nario chronologique qui nous semble fiable. Ă lâissue de cette Ă©tude, les occupations humaines, caractĂ©risĂ©es selon leurs industries, ont pu ĂȘtre replacĂ©es sur une Ă©chelle des temps en regard des variations palĂ©oclimatiques et palĂ©oenvironnementales rĂ©gionales. Plusieurs constats ont Ă©tĂ© dressĂ©s enrichissant le registre de nos connaissances sur les cultures nĂ©andertaliennes.Currently available chronological information for Middle Palaeolithic sites in southwestern France precludes the establishment of a robust chronological framework. For these early periods, developing such a framework relies upon important methodological advancements in numerical dating techniques. The results of this study are essentially based on the optical luminescence dating of sedimentary feldspars and quartz. Focusing on the most commonly employed luminescence signals (IRSL, pIR-IRSL), it was possible to more clearly evaluate the reliability of dates obtained on K-feldspars. A dating protocol for these materials based on their radioluminescence signal (IR-RF) was also developed. Optical luminescence dates were produced for six major archaeological sites: (Marillac, Charente), Combe Brune 2 (Creysse, Dordogne), Roc de Marsal (Campagne, Dordogne), Artenac (Saint-Mary, Charente), La Quina (Gardes-le-Pontaroux, Charente) et La Ferrassie (Savignac-de-Miremont, Dordogne). Collating the results for each archaeological level allowed the coherence of the dates to be tested and a reliable chronological sequence to be proposed for each site. The different human occupations, characterised by their industrial attribution, could be placed within a chronological framework that incorporates regional palaeoenvironmental and palaeoclimatic variations. Finally, several observations provide new insights for our understanding of Neandertal cultures
Evidence of shallow TL peaks contributions in infrared radiofluorescence
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Assessing the dating potential of violet stimulated luminescence protocols
© 2019 M. Sontag-GonzĂĄlez et al. publised by sciendo 2019. Violet stimulation is a new development in optical dating which has been suggested to extend the upper age limit of optically simulated luminescence (OSL) dating of quartz. Despite the reported advantage, few validation tests and applications have been published so far. The present study investigated the violet stimulated luminescence (VSL) using a single aliquot regenerative dose (SAR) protocol and a multiple aliquot additive dose (MAAD) protocol. Sedimentary quartz samples from four archaeological sites in Europe with independent age controls spanning 40-900 ka were used, including Grotte Mandrin (France), Brooksby Quarry (UK), Cueva Negra del Estrecho del RiĂł QuĂpar (Spain) and Sima de las Palomas del Cabezo Gordo (Spain). The equivalent dose of a relatively young sample (~40 ka) was successfully determined. However, significant underestimations were observed for older samples with higher doses. These findings indicate the need for further development of the measurement protocol to date high-dose natural samples
Chronology of Neanderthal burial sites in south-west France: preliminary IRSL dating results-
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Datations radionumériques : Bilan chronologique pour les sites du Sud-Ouest
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A chronology of the mousterian reindeer hunting camp of Les Pradelles (Marillac-le-Franc, France): Preliminary results
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