Oxford Radiocarbon Accelerator Unit Research Articles

ASSESSING A MODIFIED CARBONATE DIGESTION PROTOCOL FOR INCREASED CARBON DIOXIDE RECOVERY DURING CREMATED BONE PRETREATMENT

ABSTRACT Cremated bones are a commonly preserved material and often found in burial environments where unburned bone may not be preserved. As such direct radiocarbon dating of cremated bone could be essential in determining the chronology of an event. Pretreatment of cremated bone exploits the structural carbonate component of the bone which survives cremation. However, due to the low abundance (ca. 0.1%) of this component, the extraction of an amount of endogenous carbon sufficient for radiocarbon dating may represent a challenge. Here we investigate two modifications to the phosphoric acid digestion protocol used during the preparation of cremated bones at the Oxford Radiocarbon Accelerator Unit (ORAU). The first of these was to use ultrasonication to release evolved CO2 from the viscous phosphoric acid and cremated bone mixture that is formed during digestion. The second was to double the amount of time during which evolved CO2 was removed from the reaction vessel by transfer into a cryogenically cooled ampoule. Ultrasonication of the digestion mixture failed to produce a significantly higher carbon yield, while double-time collection resulted in an average 21.5±13.8% increase of C yield without affecting the measured age. Extending the collection time can better enable reliable dating of small (less than 1 g) samples.

ACHIEVING LOW BACKGROUNDS DURING COMPOUND-SPECIFIC HYDROXYPROLINE DATING: HPLC COLUMN EFFECTS

ABSTRACT Accelerator mass spectrometry (AMS) radiocarbon (14C) dating is central to the development of robust chronologies in archaeological and paleoenvironmental contexts spanning the last 50,000 years. For dates to be accurate, samples must be free of exogenous carbon contamination. At the Oxford Radiocarbon Accelerator Unit (ORAU), considerable advancements in the dating of bone collagen have been made through the development of a high performance liquid chromatography (HPLC) method for the dating of the amino acid hydroxyproline, which can mitigate the effects of carbon contamination. However, recent changes in ligand manufacturing methods for the mixed-mode column used in the ORAU protocol (Primesep A, SIELC Technologies; IL, USA) have resulted in unacceptably high analytical backgrounds. Prior to the manufacturing change, backgrounds of > 50k BP were achievable. Since the manufacturing change, a mean background of 32.5k BP has been measured. Due to column bleed, the Primesep A is therefore no longer suitable for 14C measurement of hydroxyproline from older material. Here, we present background data and the chromatography conditions used to isolate hydroxyproline using an alternative column, a preparative-scale Newcrom AH, which shows promising potential as an alternative for the routine isolation and AMS dating of hydroxyproline—especially approaching the age and mass limits of the method.

Interim report on the vertebrate deposits recovered from the Capricorn Caves, Rockhampton, Queensland

Late Pleistocene to Holocene-aged microfaunal assemblages are rarely reported in Australia despite their critical importance for palaeoecological studies, as well as their bearing on the megafaunal extinction debate. Capricorn Caves, central-eastern Queensland, hosts three Late Pleistocene to Holocene deposits containing significant faunal records. Excavations were conducted on these deposits over several seasons, with analyses of recovered material ongoing. Here, we report interim results and explore their implications for our understanding of the microfaunal record of central eastern Queensland. Fern Chamber was previously dated using U-series to the Holocene (>7.6 ± 0.2 ka). Honeymoon Suite was dated to >6.4 ± 0.2 ka using U-series. However, new charcoal dates from the deposit span approximately 7.5–15.5 ka, although the association between charcoal and fauna is unresolved. The fauna is likely Holocene. Colosseum Chamber is the oldest of the deposits, and new single-grain luminescence ages and age-depth modelling suggest that the deposit likely spans MIS 1–4. We use abundant fragmentary rodent remains to examine palaeoenvironmental change over this period. Carbon and oxygen isotope analyses of rodent incisor fragments reveal broad diets within the rodent community, and significant differences in precipitation between glacial and interglacial conditions. Rodent long bone histological analyses indicate significant differences in bone metabolism at the family level between the MIS 3 and 2 samples, but not MIS 1. We suggest that these data support evidence for a mid-Holocene arid anomaly in the region, and increased aridity through the Holocene relative to the terminal Pleistocene. The sites contain at least 10 small mammal species either globally extinct or locally extirpated, including the Capricorn rabbit-rat (Conilurus capricornensis), the white-footed rabbit-rat (Conilurus albipes), the plains mouse (Pseudomys australis), Gould’s mouse (Pseudomys gouldii), Forrest’s mouse (Leggadina forresti), the long-tailed hopping mouse (Notomys longicaudatus), swamp rat (Rattus lutreolus), the white-tailed rat (Uromys caudimaculatus), the narrow-nosed planigale (Planigale tenuirostris), the Liverpool Plains striped bandicoot (Perameles fasciata), the Cape York brown bandicoot (Isoodon peninsulae), and the southern brown bandicoot (Isoodon obesulus). We also record significant range contractions for frogs (Philoria sp., Neobatrachus sp.) and earless dragons (Tympanocryptis sp.). This study demonstrates that significant changes in the microfaunal community of tropical Queensland occurred between the Late Pleistocene and the late Holocene. It also reinforces how poorly recorded native faunas are from the late Holocene through the historical period, to today. Such records underpin and are thus vital for modern biodiversity conservation efforts.Julien Louys [j.louys@griffith.edu.au], Australian Research Centre for Human Evolution, Griffith University, Brisbane, Australia; Jonathan Cramb [jonathan.cramb@qm.qld.gov.au], Queensland Museum, Brisbane, Australia; Kyle Ferguson [k.ferguson81@outlook.com.au], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia; Justine Kemp [j.kemp@griffith.edu.au], Australian Research Centre for Human Evolution, Griffith University, Brisbane, Australia; Rachel Wood [rachel.wood@arch.ox.ac.uk], School of Archaeology and Anthropology, Australian National University, Canberra, Australia and Oxford Radiocarbon Accelerator Unit (ORAU), University of Oxford, Oxford, UK; Justyna J. Miszkiewicz [j.miszkiewicz@uq.edu.au], School of Social Science, University of Queensland, Brisbane, Australia and Naturalis Biodiversity Center, Leiden, the Netherlands; Nathalia R. Dias Guimarães [ndg0601@gmail.com], School of Archaeology and Anthropology, Australian National University, Canberra, Australia; Penny Higgins [pennilyn.higgins@gmail.com], EPOCH Isotopes, 6606 E Townline Road, Williamson, NY 14589, USA; Kenny J. Travouillon [Kenny.Travouillon@museum.wa.gov.au], Western Australian Museum, Perth, Australia; Scott A. Hocknull [scott.hocknull@qm.qld.gov.au], Geosciences, Queensland Museum, Brisbane, Australia; Gregory E. Webb [g.webb@uq.edu.au], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia; Gilbert J. Price [g.price1@uq.edu.au], School of Earth and Environmental Science, The University of Queensland, Brisbane, Australia.

Последние результаты датирования фаунистических остатков в Костёнках

The Kostenki-Borshchevo sites have great potential for high-resolution and robust Upper Palaeolithic chronologies. However, radiocarbon dating the sites has proved problematic: in some cases radiocarbon dates do not align with the geo-chronological position of layers, and in other cases a wide span of radiocarbon dates is inconsistent with the nature of the archaeological assemblage. One problem now shown to lead to erroneous results is the incomplete removal of exogenous carbon from dated samples. The past two decades have seen renewed efforts to improve this situation, via development of improved sample pretreatment methods. In light of this, two recent Leverhulme-Trust-funded projects have carried out programs of radiocarbon dating of bone from Kostenki at the Oxford Radiocarbon Accelerator Unit (ORAU). This paper brings together the published results of those projects. This work has significantly improved the chronology of several Kostenki sites, and in doing so has addressed some long-standing chronological questions. This work also highlights ongoing difficulties in radiocarbon dating earlier-Upper-Palaeolithic-age material using standard pretreatment methods.

Prehistoric communities of the River Dee

This volume presents the results of archaeological fieldwork undertaken along the River Dee, Aberdeenshire, north-east Scotland, by the Mesolithic Deeside voluntary community archaeology group between 2017 and 2019. A total of 42 fields were investigated, from which over 11,000 lithics were recovered, representing at least 15 archaeological sites and a span of human activity covering some 10,000 years from around 12,000 BC to c 2000 BC. Finds from the Late Upper Palaeolithic, Mesolithic, Neolithic and Bronze Age were present. Work comprised fieldwalking, test pitting, specialist analysis, and small-scale excavation. The investigation described here is significant not just for the light it throws on the early prehistoric populations along the River Dee but also for the methodology by which investigation was undertaken, as this provides a potential model for work in other areas. Both aspects are covered in the report.
 The River Dee flows between postglacial gravel and sand terraces, the structure of which has played an important role for the early settlers of the area, and this is covered in some detail in order to provide the physical background framework for the sites. There are also sections on more specialised geophysical and geoscience techniques where these were undertaken, together with a summary of research on the palaeoenvironmental conditions throughout the millennia of prehistory. The artefactual evidence comprises lithic assemblages which were all catalogued as fieldwork progressed; the contents of each site are presented, together with more detailed analysis of the finds from test pitted sites. Finally, given the rich archaeological record from the area, the results of the present project are set into the wider context of the evidence for prehistoric settlement along the river, and there is consideration of future directions for further fieldwork.
 While all authors have contributed to the whole volume, individual sections that present specialist work by specific teams have been attributed. The distribution maps and GIS are the work of Irvine Ross.
 Dates given are calibrated BC dates. The Nethermills Farm NM4 dates are calibrated using the Oxford Radiocarbon Accelerator Unit calibration program OxCal 4 (Bronk Ramsey 2009) and their date ranges are calibrated using the IntCal13 atmospheric calibration curve (Reimer et al 2013). Optically stimulated luminescence (OSL) was used to profile sediment accumulations on some of the sites and obtain information relating to site formation, but it was not used for dating in any of the projects.

Хронология неолитической керамики Байкало-Енисейской Сибири: основные идеи и новые данные

There are two main research areas in the Neolithic studies of the Baikal-Yenisei Siberia. One of them relates to research of mortuary traditions, another with a research of hunter-gatherer’s campsites. Ceramics is of the greatest importance for the cultural identification of campsites complexes. As a result of the Canadian-Russian project, for the Neolithic burials a clear chronological model based on AMS radiocarbon dates corrected for the freshwater reservoir effect (FRE) was created. There are several hypotheses for ceramic complexes that were proposed, but all of them predominantly were based on the radiocarbon dates obtained by the liquid scintillation counting method. This data cannot be admitted as reliable because of the limitation of this method, the big root-mean-square deviation, and the lack of data on stable carbon and nitrogen isotopes. Over the past few years, we have received in the Keck-CCAMS Group and Oxford Radiocarbon Accelerator Unit laboratories 35 new AMS-radiocarbon dates for the complexes with Neolithic ceramics. Samples taken for analyses were obtained from the 14 multilayered sites of the Angara region, Tunka valley, and Lake Baikal coast. They are represented by fragments of teeth, bones, and horns of the mammals (predominantly Cervidae and large ungulates) that accompanied pottery in cultural horizons. In five cases the carbonized organic residues (foodcrusts) from the inner surface of ceramic vessels were used as samples. In one more case, it was a strong humified soil cleaned from impurities. The technical assessment of the reliability of all dates was provided. The definitions obtained for faunal remains look the most correct. Dates obtained for foodcrust are likely significantly older, because of possible FRE influence. The geoarchaeological assessment of new dates and their correlation with the most reliable dates of previous years is provided. Based on the AMC-dating, the following chronometric frames for the Neolithic pottery of the Baikal-Yenisei Siberia are offered: Early Neolithic Net-impressed and the Khaita ceramics in the Angara region – 8539–6914 cal BP, on the Lake Baikal coast – 8160–6960 cal BP, in the Tunka valley – 7843–7681 cal BP; Ust-Belaya ceramics in the Northern Angara region – 7421–7014 cal BP (perhaps the real age is younger), in the Southern Angara region – 6730–6306 cal BP; Posolskaya ceramics on the Lake Baikal coast – 6750–6300 cal BP, in the Southern Angara region – 6730–6306 cal BP; Serovo and Dotted-comb ceramics on the Lake Baikal coast – 5841–4620 cal BP.

Twenty years on, a new date with Lascaux. Reassessing the chronology of the cave’s Paleolithic occupations through new 14C AMS dating

Aside from the stylistic debates and quarrels fueled by the studies of its painted and engraved walls, the Lascaux Cave stands out by its very weak and contradictory radiometric framework (Delluc and Delluc 2012). In addition to this, no comprehensive, interdisciplinary study of the rich archaeological assemblages has been conducted for almost forty years (Leroi-Gourhan and Allain 1979). The LAsCO project (Langlais and Ducasse coord.) aims to fill this gap by proposing a global reassessment of the osseous and lithic artifacts, ornaments, ochres and lamps. As part of this work, a new effort has been made to clarify the Paleolithic chronology of the human activities documented by this stratified evidence. Five reindeer remains taken from the cave’s main areas (Axial Gallery, Passageway, Nave, Shaft), some showing clear evidence of anthropic exploitation, were therefore selected to be dated in order to test (1) the chronological homogeneity of the occupations, as already suggested by a high typo-technological coherence and, if this was confirmed, (2) the hypothesis of an attribution to the Badegoulian-to-Magdalenian transition phase, as indicated by prior inter-site comparisons (Langlais 2010 ; Ducasse et al. 2011; DEX_TER project: Ducasse and Langlais coord.). All the selected samples were sent to the Oxford Radiocarbon Accelerator Unit (ORAU) and run on a MIni CArbon DAting System (MICADAS) after an ultrafiltration pretreatment. While the sample from the Passageway area failed due to low collagen yield, the other four produced reliable and highly comparable measurements centered on a 14C age of 17,600 uncal. BP (21.5-21 cal ka BP). These results confirm the two basic assumptions described above and contradict the diachronic framework defined by the 1948-2002 radiometric data, while restoring a certain degree of chronological consistency which fits well with the main typo-technological features of the lithic and osseous equipment (Allain 1979, Leroy-Prost 2008 and ongoing analysis). After a brief outline of the existing radiometric data and a detailed description of the sampling and dating strategy, the reliability of the results and their impact on our understanding of the cave’s phase(s) of occupation(s) are discussed in depth. While the issue of the precise “cultural” attribution of the dated assemblages and the links between the latter and the parietal art are beyond the scope of this paper, these new data represent a first but significant step towards a global renewal of the highly controversial chronological framework of the Lascaux Cave.

The Importance of Open Access to Chronological Information: The IntChron Initiative

ABSTRACTThe development of chronologies relies on integrating information from a number of different sources. In addition to direct dating evidence, such as radiocarbon dates, researchers will have contextual information which might be an environmental sequence or the context in an archaeological site. This information can be combined through Bayesian or other types of age-model. Once a chronology has been developed, this information can be used to estimate, for example, chronological uncertainties, rates of change, or the age of material which has not been directly dated.Dealing with the information associated with chronology building is complicated and re-evaluation of chronologies often requires structured information which is hard to access. Although there are many databases with primary dating information, these often do not contain all of the information needed for a chronology. The Chronological Query Language (CQL) developed for OxCal was intended to be a convenient way of pulling such information together for Bayesian analysis. However, even this does not include much of the associated information required for reusing data in other analyses.The IntChron initiative builds on the framework set up for the INTIMATE (Integrating Ice core, Marine and Terrestrial Records) chronological database (Bronk Ramsey et al. 2014) and is primarily an information exchange format and data visualization tool which enables users to pull together the types of information needed for chronological analysis. It is intended for use with multiple dating methodologies and while it will be integrated with OxCal, is intended to be an open format suitable for use with other software tools. The file format is JSON which is easily readable in software such as R, Python and MatLab. IntChron is not primarily intended to be a data depository but rather an index of sites where information is stored in the relevant format. As an initial step, databases of radiocarbon dates from the Oxford Radiocarbon Accelerator Unit (including those for the NERC radiocarbon facility), the RESET tephra database, the INTIMATE chronological database and regional radiocarbon databases for Egypt and Southern Africa are all linked. The intention is that users of OxCal will also be able to make published data accessible to others and to store working data, visible only to the user, to be used with the associated analysis tools. The IntChron site allows data from third party sources to be accessed through a representational state transfer (REST) application programming interface (API) in a number of different formats (JSON, csv, txt, oxcal) and associated bibliographic information in BibTeX format.The aim of the IntChron initiative is to make it easy for users to provide data (in the single JSON format with limited minimum requirements) as well as to access data and tools, while promoting robust chronologies including realistic estimates of uncertainties. It is hoped that this will help to bring the chronological research communities to a point where data access is as easy as it is in some other fields. This is particularly important for Early Career Researchers and for those seeking to use large datasets in novel ways.

Radiocarbon Dates from the Oxford AMS System: Archaeometry Datelist 36

This is the thirty‐sixth list of AMS radiocarbon determinations measured at the Oxford Radiocarbon Accelerator Unit (ORAU). Amongst some of the sites included here are the latest series of determinations from the key sites of El Mirón (Spain) and Sutton Courtney (UK), as well as others dating to the Palaeolithic, Mesolithic and later periods. Submitters of the material provide comments on the significance of the results.

Nitrogen content variation in archaeological bone and its implications for stable isotope analysis and radiocarbon dating

The collagen component of ancient bones is routinely isolated for radiocarbon dating and stable isotope studies. However, it is impossible to tell the state of collagen preservation from visual inspection of bones. At the Oxford Radiocarbon Accelerator Unit (ORAU), the percent nitrogen by weight (%N) of a ∼5 mg sample of bone powder is measured on a mass spectrometer and used as a proxy for protein content. A previous study showed that samples with %N > 0.76 are considered likely to produce sufficient collagen for radiocarbon dating (Brock et al., 2010b). However, the extent of variation between bone %N and collagen yield is unclear, as is the intra-bone variation in %N. Here, we report a series of tests performed on Palaeolithic bones known to have variable collagen preservation. This new study shows significant variation in %N within the same bone and that there is sometimes a lack of correlation between %N and collagen yield. These results suggest that for bone samples from difficult environments or from Pleistocene contexts, it may be worth sub-sampling for %N in different locations of the bone (if possible) and then attempting to extract collagen from marginally preserved bones (%N around 0.2–0.7%), as they may still yield sufficient collagen for isotope and dating studies.

Testing the Effectiveness of Protocols for Removal of Common Conservation Treatments for Radiocarbon Dating

AbstractTo achieve a reliable radiocarbon (14C) date for an object, any contamination that may be of a different age must be removed prior to dating. Samples that have been conserved with treatments such as adhesives, varnishes or consolidants can pose a particular challenge to14C dating. At the Oxford Radiocarbon Accelerator Unit (ORAU), common examples of such substances encountered include shellac, the acrylic polymers Paraloid B-67 and B-72, and vinyl acetate-derived polymers (e.g. PVA). Here, a non-carbon-containing absorbent substrate called Chromosorb®was deliberately contaminated with a range of varieties or brands of these conservation treatments, as well as two cellulose nitrate lacquers. A selection of chemical pretreatments was tested for their efficiency at removing them. While the varieties of shellac and Paraloid tested were completely removed with some treatments (water/methanol and acetone/methanol/chloroform sequential washes, respectively), no method was found that was capable of completely removing any of the vinyl acetate-derived materials or the cellulose nitrate lacquers. While Chromosorb is not an exact analog of archaeological wood or bone, for example, this study suggests that it may be possible to remove aged shellac and Paraloid from archaeological specimens with standard organic solvent-acid-base-acid pretreatments, but it may be significantly more difficult to remove vinyl acetate-derived polymers and cellulose nitrate lacquers sufficiently to provide reliable14C dates. The four categories of conservation treatment studied demonstrate characteristic FTIR spectra, while highlighting subtle chemical and molecular differences between different varieties of shellac, Paraloid and cellulose nitrate lacquers, and significant differences between the vinyl acetate derivatives.

Laboratory Intercomparison of Pleistocene Bone Radiocarbon Dating Protocols

AbstractSince its invention in the late 1940s, radiocarbon (14C) dating has become an important tool for absolute dating. A prerequisite for the acceptance of this method is consistency between, and compatibility of, 14C dates from different laboratories. To meet these requirements, international laboratory intercomparison studies with different sample materials are frequently performed (e.g. TIRI, FIRI, VIRI and, most recently, SIRI).Intercomparison is especially relevant and difficult for samples close to the dating limit of ~50 kBP, not least for bone samples. A 14C intercomparison study between the Leibniz-Laboratory in Kiel (Germany), the Center for Isotope Research (CIO) in Groningen (the Netherlands), and the Oxford Radiocarbon Accelerator Unit (ORAU, United Kingdom) was performed on three Pleistocene (MIS3) mammal bone samples from the Brick Quarry site Coenen (BQC) in Germany. The comparison of individually prepared and measured bone collagen 14C activities, results from shared collagen measurements, and respective background signatures and correction points to the latter as the main factor responsible for observed differences in final given radiocarbon estimates.

Holocene Fishing in the Big Sea Region of Lake Baikal (Based on Materials from Multilayered Habitation Sites)

This article offers new data on ancient fi shing in the Big Sea region of Lake Baikal. Materials for this research were recovered during fieldwork conducted at multilayered habitation sites Sagan-Zaba II and Buguldeika II by the joint Russian-Canadian expeditions (a project between Irkutsk State University (Russia) and University of Alberta (Canada)). The research presented here is based on the analysis of ichthyofaunal remains and artefacts associated with fishing activities (hooks, harpoons, net sinkers, and fish imagery). For the first time, we are able to reconstruct not only taxa and fishing techniques used but also to trace which species were consumed during different chronological periods. Chronological assessment of analyzed cultural layers at Sagan-Zaba II and Buguldeika II was done through over 90 AMS radiocarbon dates made on ungulate bones in Oxford Radiocarbon Accelerator Unit. Archaeological periodization of analyzed sites spans from the Mesolithic to the ethnographically contemporary period. Fish species composition at the two sites was compared with that from sites of the Little Sea area of Lake Baikal. These new data added a better understanding of the relative importance and subsistence uses of fish on Lake Baikal during the Holocene period. It has been demonstrated that fishing traditions of Early and Middle Holocene hunter-gatherers were continued by pastoralists, especially in regard to the consumption of deep-water species. It is concluded that ancient populations living on the shores of Lake Baikal exploited a wide range of natural resources, and fishing played a very important part in this.

Evaluation of Sample Preparation Protocols for the 14C Dating of Tupiguarani Pottery in Southeastern Brazil

AbstractThis study evaluates the radiocarbon dating of ceramic samples from Tupiguarani sites in Brazil, a settlement type dating up to 3000 cal BP. In this work, residues from ceramic samples from four archaeological sites in Rio de Janeiro (Morro Grande, Serrano, Barba Couto, and Bananeiras) were analyzed. In order to identify the most suitable sample preparation protocols, the humic fraction was isolated from the bulk material at the Oxford Radiocarbon Accelerator Unit (ORAU), whereas the acid-base-acid (ABA) residue fraction method was applied at the Radiocarbon Laboratory of the Fluminense Federal University (LAC-UFF). The dating results were compared to the current knowledge about the occupational periods of the sites. For the Morro Grande site, the results of humic and ABA residue fractions show a difference of more than 1500 yr. For the Serrano site, the 14C ages obtained from the two pretreatments are identical, and as with the Barba Couto and Bananeiras sites, indicate an occupation during the Brazilian colonial period of the 16th century AD and are compatible with the archaeological data.

When Dental Enamel is Put to the Acid Test: Pretreatment Effects and Radiocarbon Dating

AbstractThe influence of hydrochloric acid pretreatment on F14C and radiocarbon dates from dental enamel was investigated. Samples from modern equine incisors, a Roman cattle molar, and a Paleolithic woolly rhino molar were sampled and subsequently divided into five fractions. Each fraction was pretreated with a different acid solution, analyzed with Fourier transform infrared spectroscopy (FTIR), and accelerator mass spectrometry (AMS) 14C dated at the Oxford Radiocarbon Accelerator Unit (ORAU). When compared to a control date (e.g. dentine collagen), better results were observed when increased concentrations of hydrochloric acid solution were used in the chemical pretreatment. This pilot study suggests that decontamination of younger samples may be possible. However, for more fossilized samples with a high level of contamination (e.g. from the European Paleolithic), acid pretreatment under the conditions used in this study does not remove all contamination.

A Reassessment of the Routine Pretreatment Protocol for Radiocarbon Dating Cremated Bones

AbstractIn the late 1990s, it was demonstrated that reliable radiocarbon dates could be obtained directly from cremated bone. Many 14C laboratories have since used a protocol for pretreating cremated (calcined) bones that consists of consecutive treatments with bleach and acetic acid to remove organic matter and extraneous or diagenetic carbonate, respectively. In most instances, the bleach used is sodium hypochlorite, although in recent years the Oxford Radiocarbon Accelerator Unit (ORAU) has used acidified sodium chlorite instead. However, properly calcined (white) bones should not contain any organic material; hence, the bleach treatment is potentially unnecessary. This article describes studies investigating the effectiveness of bleach (and the specific bleach used) during pretreatment of calcined bone, and demonstrates that 14C dates on six cremated bone samples are statistically indistinguishable whether or not the initial bleach step is applied.

Working with the Public: How an Unusual Museum Enquiry Turned into Travels Through Time and Space

Museum enquiries offer a unique opportunity to engage on a one-to-one level with members of the public. This paper covers an unusual enquiry from 2013 of an unknown tooth that was brought into Plymouth City Museum and Art Gallery for identification. We highlight how museum enquiries can engage with members of the public by involving them directly with original scientific research. The tooth was found in a garden in Plymouth with no associated data of about where it originated. We identified the tooth, and the enquirer researched the history of the house. The tooth gave the appearance of a sub-fossil so with the large number of Quaternary sites in Plymouth, together with the identification of the previous owner on the site, there were valid reasons to undertake testing of the tooth to determine its origin. Strontium (Sr) isotope analysis of the tooth was carried out to determine if the tooth was British and radiocarbon dating was undertaken to work out the age of the tooth. The 87Sr /86Sr of the leopard tooth gave a value of 0.716131, with Sr concentrations at 568ppm. This is a high concentration of Sr ppm relative to other British data, suggesting a non-British origin. The radiocarbon measurement was 187 ± 24 years BP (University of Oxford Radiocarbon Accelerator Unit reference OxA-30390). This places the tooth not in the Pleistocene, but between 1739 and 1787 AD. The site where the tooth was discovered was owned by the brother of Linnaeus Tripe who travelled across India and Burma. We argue that the results of this study demonstrate that this leopard tooth was originally from India or Burma, and brought into Britain by Tripe. A correction article relating to the radiocarbon dates included in this publication can be found here: http://dx.doi.org/10.5334/oq.aj

Radiocarbon Dates from the O xford AMS S ystem: A rchaeometry Datelist 35

This is the 35th list of AMS radiocarbon determinations measured at the Oxford Radiocarbon Accelerator Unit (ORAU). Amongst some of the sites included here are the latest series of determinations from the key sites of Abydos, El Mirón, Ban Chiang, Grotte de Pigeons (Taforalt), Alepotrypa and Oberkassel, as well as others dating to the Palaeolithic, Mesolithic and later periods. Comments on the significance of the results are provided by the submitters of the material.

Wood Pretreatment Protocols and Measurement of Tree-Ring Standards at the Oxford Radiocarbon Accelerator Unit (ORAU)

This article presents the pretreatment protocols for wood samples processed at the Oxford Radiocarbon Accelerator Unit (ORAU), including recent implementation of a purification method to α-cellulose for non-routine samples. We examine the long-term reproducibility of measurement on wood samples at ORAU through the >1000 14C determinations made on known-age tree-ring standards processed in each AMS wheel since our present High Voltage Engineering Europa (HVEE) AMS system came on-line in September 2002. A discussion of background measurements is also provided.

Wood Pretreatment Protocols and Measurement of Tree-Ring Standards at the Oxford Radiocarbon Accelerator Unit (ORAU)

This article presents the pretreatment protocols for wood samples processed at the Oxford Radiocarbon Accelerator Unit (ORAU), including recent implementation of a purification method to α-cellulose for non-routine samples. We examine the long-term reproducibility of measurement on wood samples at ORAU through the >100014C determinations made on known-age tree-ring standards processed in each AMS wheel since our present High Voltage Engineering Europa (HVEE) AMS system came on-line in September 2002. A discussion of background measurements is also provided.