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Late Quaternary fluvial channel deposits are notoriously difficult to date. In the midwestern United States, shells of aquatic mollusks can be found within many fluvial channel sediments and therefore can be radiocarbon (14C) dated to determine the age of the deposits. However, carbonate platform rocks are abundant in this region, potentially causing freshwater 14C reservoir effects (FRE) in mollusk shells. We 14C dated 11 aquatic gastropod and bivalve shell samples from specimens collected live from a stream in southwestern Ohio during three different years to assess the modern 14C reservoir effect. Modern samples yielded an average 14C FREmodern of 518 ± 65 14C yrs for 2020 (n=5), 640 ± 34 14C yrs for 2021 (n=2), and 707 ± 76 14C yrs for 2022 (n=4). We also 14C dated matched pairs of organic wood or charcoal and aquatic mollusk shells from late Pleistocene and Holocene deposits in the Four Mile Creek floodplain to determine the FREfossil. These samples, free of any potential influence from nuclear bomb testing, yielded an overall weighted mean FREfossil of 1029 ± 345 14C yrs. We then assess the advantages and limitations of both the FREmodern and FREfossil methods for determining freshwater reservoir effects. Finally, we apply the FREfossil correction to a series of shell ages from fluvial terrace deposits as a case study. The results indicate that although there is a 14C FRE in streams from the midwestern United States, aquatic shells can provide robust age control on fluvial channel deposits. More research is needed to understand the spatial and temporal variability of FREs, as well as any species effects, among various watersheds across the midwestern United States.
Skin-based samples (leather, skin, and parchment) in archaeological, historic and museum settings are among the most challenging materials to radiocarbon (14C) date in terms of removing exogenous carbon sources—comparable to bone collagen in many respects but with much less empirical study to guide pretreatment approaches. In the case of leather, the 14C content of materials used in manufacturing the leather can vary greatly. The presence of leather manufacturing chemicals before pretreatment and their absence afterward is difficult to demonstrate, and the accuracy of dates depends upon isolating the original animal proteins and removing exogenous carbon. Parchments differ in production technique from leather but include similar unknowns. It is not clear that lessons learned in the treatment of one are always salient for treating the other. We measured the 14C content of variously pretreated leather, parchment, skin samples, and extracts, producing apparent ages that varied by hundreds or occasionally thousands of years depending upon sample pretreatment. Fourier Transform Infrared Spectroscopy (FTIR) and C:N ratios provided insight into the chemical composition of carbon reservoirs contributing to age differences. The results of these analyses demonstrated that XAD column chromatography resulted in the most accurate 14C dates for leather and samples of unknown tannage, and FTIR allowed for the detection of contamination that might have otherwise been overlooked.
Museum collections are extremely valuable sources of material for ongoing research, although the conservation history of some objects is not always recorded, which can be problematic for chemical analyses. While most contamination is removed using the acid-base-acid treatment, this may not be the case for cross-linked contamination. The XAD resin protocol was implemented at the radiocarbon (14C) laboratory in the Muséum national d’Histoire naturelle, and the setup was tested using known age bone samples and a consolidated Palaeolithic bone. Known age samples were consolidated with shellac or Paraloid, aged for a month, treated with or without the XAD resin and 14C dated. Bone blank results showed that XAD resin was able to remove shellac, which was not the case for the ABA-only method. Results from VIRI I were more variable and VIRI F was possibly too young to show the effects of the consolidants. Two 14C dates on the Palaeolithic bone after XAD treatment are statistically the same, while a sample without XAD treatment was significantly older, suggesting that the contaminant was not fully removed by the ABA-only treatment. This study demonstrates the potential of the XAD treatment to clean heritage bone samples stored in museums prior to geochemical analyses.
Lacquerwork technologies comprise multiple techniques depending on countries, time, and traditions. Carved Asian lacquers applied on wooden objects consist of multiple thin uncolored or pigmented layers spread over the surface. To radiocarbon (14C) date these types of objects, often only the wooden structure is used. Here we report on a set of carved lacquered objects that were dated based on stylistic form, 14C dating of the wooden structure and of the Asian lacquers. THM-Py-GC-MS and micro-Raman spectroscopy were used to confirm the molecular composition of the lacquers and helped assessing the pretreatment protocol. The lacquers analyzed contained between 20 and 50% wt carbon, thus 2–5 mg of sample were necessary for 14C dating. The dates obtained on wood and lacquers showed a reliable correlation. The results suggest that, in most cases, it is sufficient to sample a part of the lacquer layers to date an object. We advise to perform an acid pretreatment followed by a successive solvent immersion with an increasing polarity. Dating different components of a lacquered object can also help to understand previous restoration interventions that frequently occur for ancient lacquered objects. Ceramic, metallic, and other objects covered with Asian lacquers can also be dated using this approach.
Radiocarbon dates on charred plant remains are often used to define the chronology of archives such as lake cores and fluvial sequences. However, charcoal is often older than its depositional context because old-wood can be burnt and a range of transport and storage stages exist between the woodland and stream or lake bed (“inherited age”). In 1978, Blong and Gillespie dated four size fractions of charcoal found floating or saltating in the Macdonald River, Australia. They found larger fragments gave younger age estimates, raising the possibility that taphonomic modifications could help identify the youngest fragments. In 1978 each date required 1000s charcoal fragments. This study returns to a sample from the Macdonald River to date individual charcoal fragments and finds the inherited age may be more than 1700 years (mode 250 years) older than the collection date. Taphonomic factors, e.g., size, shape or fungal infestation cannot identify the youngest fragments. Only two fragments on short-lived materials correctly estimated the date of collection. In SE Australia, this study suggests that wood charcoal will overestimate the age of deposition, taphonomic modifications cannot be used to identify which are youngest, and multiple short-lived materials are required to accurately estimate the deposition age.
Analysis of 20 calibrated accelerator mass spectrometry radiocarbon (AMS 14C) ages reveals a chronology for the habitation of a unique peripheral settlement at Zahrat adh-Dhra‘ 1 (ZAD 1), Jordan during the Middle Bronze Age of the Southern Levant. Bayesian modeling distinguishes three phases of occupation between the first settlement at ZAD 1, perhaps as early as about 2050 cal BCE, and its abandonment by 1700 cal BCE. ZAD 1 represents a marginal community, both environmentally and culturally, on the hyperarid Dead Sea Plain, and exemplifies the peripheral settlements that are envisioned as important elements of Bronze Age Levantine society. Most importantly for this study, it is the only peripheral site in the Southern Levant that provides a Bayesian model for its habitation during the growth of Middle Bronze Age urbanized society. The timing of ZAD 1’s constituent phases, early in Middle Bronze I, across the Middle Bronze I/II transition and in Middle Bronze II, correspond well with emerging chronologies for the Middle Bronze Age, thereby contributing to an ongoing reassessment of regional social and settlement dynamics.
In this study, the temporal accession date of king Pepy II is modeled by using a series of 14C dates based on samples from the burial of Djau at Deir el-Gebrawi in Middle Egypt. Djau was one of Pepy II’s officials—overseer of Upper Egypt and nomarch of the 8th and 12th provinces. Five samples of Djau’s wrapping as well as his wooden coffin were analyzed. ATR-FTIR (Attenuated Total Reflection–Fourier Transform InfraRed spectroscopy) analyses were carried out on textile samples to ensure they were not contaminated by organic chemicals due to the embalming process, prior to being dated using the conventional radiocarbon method at the IFAO Laboratory (Cairo). Based on archaeological evidence, the temporal density associated with Djau’s death is then used as a chronological marker for the death date of king Pepy II. Taking into account the possibility of either biennial, annual or irregular censuses to assess the duration of his reign, the accession date of Pepy II is thus modeled using OxCal software. The results place king Pepy II’s accession date between 2492 to 2256 BCE with 95.4% probability, and between 2422 to 2297 BCE with 68.3%.
Biobased content analysis is a well-established, analytically independent, standardized method to determine the biobased content of fuels and plastics, based on differences of the specific radiocarbon (14C) activity of fossil and recent biogenic compounds. This biogenic content analysis can be useful for the producers as a quality assurance tool, for the customers as feedback about the truly biobased products and for the control organizations as an independent analytical tool to prove the biological origin. More than 100 commercially available foods, cosmetics, and drug samples have been used for biobased carbon content analysis by accelerator mass spectrometry (AMS) 14C measurement to demonstrate the potential of this technique. Our results show that this measurement technique is a unique tool for the determination of biocontent in foodstuff and medical products. Most of the tested materials were nearly or completely biobased (≥ 98 pMC), and no completely fossil-based final product was detected. The lowest biogenic compound was measured in a vanilla aroma flavor. In 45 of the 102 samples selected a wide range (2–98%) presented fossil-based carbon content. The method can be applied for monitoring raw materials and final products for biobased content in the industry and consumer protection as well.
We have radiocarbon-dated the main settlement of Skarkos (Skarkos II) on the Cycladic island of Ios, using a set of animal bone samples. The site of Skarkos stands on a hill in a coastal plain, mid-way down the western side of Ios island and about 1 km from the island’s harbour. It is the first time this important settlement with a wealth of finds and an extraordinary building system with two-storey houses is dated in absolute terms complementing the chronology of the Cycladic EBA II period. The radiocarbon determinations show that the major phase of the settlement came to an end between circa 2550 and circa 2500 BC. The dates also confirm the archaeological evidence that the main occupation period is dated archaeologically to the EC II period (Keros-Syros culture). Furthermore, in order to embed the new Skarkos dates within the overall Cycladic chronology and define better the end of the EC II phase, we treated the Skarkos dates together with published dates from other Cycladic sites using Bayesian analysis considering two different models.
This commentary aims at raising awareness and fostering a discussion on the need of a new approach to the radiocarbon (14C) dating of historic mortars. Over the last decades, important advancements have been made in the application of the 14C dating methods to lime mortar samples, including the use of lime lumps instead of generic pieces of mortar. However, a relevant number of results in disagreement with the chronological framework of the related archaeological cases are published every year without a clear understanding of the reasons for such results. This suggests that further developments to the methodology are needed. The commentary argues that to further develop this particular application of the 14C dating method, a new, more holistic approach is needed that moves away from the very “applied” approach that dominated the last decades and focuses more on the causes of contamination and the mechanism of the reactions involved. Two actions are suggested that can immediately improve our ability to critically assess the results obtained: the publication of a chemical and mineralogical characterization of the binding fraction for the dated mortars, and the publication of sampling depth for each dated sample.
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.
Studies of pre-bomb mollusks live-collected around the Australian coastline have concluded that near-shore marine radiocarbon reservoir effects are small and relatively uniform. These studies are based on limited samples of sometimes dubious quality representing only selective parts of Australia’s lengthy coastline. We systematically examine spatial variability in the marine radiocarbon reservoir effect (ΔR) through analysis of 292 live-collected mollusk samples across the Australian mainland coasts and near-shore islands subject to strict selection criteria. This study presents 233 new ΔR values combined with an evaluation of 59 previously published values. Results demonstrate significant spatial variability in marine radiocarbon reservoir effects across the study region. ΔR values range from 68 ± 24 14C years off the Pilbara region of Western Australia to –337 ± 46 14C years in the southern Gulf of Carpentaria in Queensland. Most sets of local values exhibit internal consistency, reflecting the dominant influence of regional oceanography, including depletion in ΔR values southwards along the eastern Australian coastline coincident with the East Australian Current. Anomalous values are attributed to inaccurate documentation, species-specific relationships with the carbon cycle and/or short-term fluctuations in marine radiocarbon activities. To account for the heterogeneous distribution of marine 14C, we recommend using a location specific ΔR value calculated using the Australian ΔR Calculator, available at: https://delta-r-calc.jcu.io/.
Bone points were one of the major hunting implements in northern European hunter-gatherer societies. They differ in shapes, types, and manufacturing techniques. In this paper, we investigate 22 bone points from the territory of Lithuania, by studying their morpho-technological characteristics, direct dates, and adhesive residues. The majority are isolated finds, but four points were selected from excavated archaeological sites dated between the 5th and 3rd millennia cal BC. Most of the points belong to the barbed points category, but six slotted points were also studied. Of the 22, 16 previously undated points were sampled for accelerator mass spectrometry radiocarbon (AMS 14C) dating. The results of 10 successfully dated samples are discussed together with previously published 14C dates of bone points from the same region. ATR-FTIR analysis of adhesive residues from six points suggest that birch bark tar was used to haft barbed points and lithic inserts. The results reveal the diversity of types of Early Holocene bone points in the territory of Lithuania, while the slotted and Kunda-type bone points fall into narrow timeframes.
We present case studies on three objects of high importance for cultural heritage in southern Poland, dated in years 2018–2022 at the Gliwice 14C and Mass Spectrometry Laboratory with radiocarbon (14C) and dendrochronology methods. The first was a richly ornamented wooden cane, discovered during excavations on the market in Bytom city. The cane can be associated with medieval court proceedings. The archaeological context indicates the 13th century AD, and the 14C result corresponds perfectly with this time, confirming that it is the oldest object of this type in Poland. The second was a 4-m-tall oak column from St. Leonard Church in Lipnica Murowana, a UNESCO heritage site. The local story said it was previously devoted to Światowid, a pagan deity. Our analysis excluded the pre-Christian age, as the tree was felled no earlier than the late 15th century, which is in agreement with historical records. The third was a wooden Saint Lawrence Church in Bobrowniki. The presbytery was covered with up to five layers of polychromic paintings, some of high artistic value. We dated three samples from the original wooden board, and by wiggle-matching, the calibrated age interval was narrowed to 1731–1754 cal AD.
Sample materials such as sediments and soils contain complex mixtures of different carbon-containing compounds. These bulk samples can be split into individual fractions, based on the temperature of thermal decomposition of their components. When coupled with radiocarbon (14C) measurement of the isolated fractions, this approach offers the advantage of directly investigating the residence time, turnover time, source, or age of the different components within a mixed sample, providing important insights to better understand the cycling of carbon in the environment. Several laboratories have previously reported different approaches to separate radiocarbon samples based on temperature in what is a growing area of interest within the research community. Here, we report the design and operation of a new ramped oxidation facility for separation of sample carbon on the basis of thermal resistance at the NEIF Radiocarbon Laboratory in East Kilbride, UK. Our new instrumentation shares some characteristics with the previously-reported systems applying ramped oxidation and/or ramped pyrolysis for radiocarbon measurement, but also has several differences which we describe and discuss. We also present the results of a thorough program of testing of the new system, which demonstrates both the reproducibility of the thermograms generated during sample combustion, and the reliability of the radiocarbon measurements obtained on individual sample fractions. This is achieved through quantification of the radiocarbon background and analysis of multiple standards of known 14C content during standard operation of the instrumentation.
The Early Iron Age hillfort in Chotyniec (SE Poland) is the westernmost permanent settlement of the Scythian cultural circle. Recognizing the construction of the fortified settlement’s ramparts and their chronology was considered one of the priorities of the systematic research conducted since 2016. Based on 18 radiocarbon dated samples from different parts of the rampart, a chronological model of its functioning was made. It indicates that the construction of this monumental fortifications protecting the settlement in Chotyniec should be dated to between 651–595 or 531–409 BC. This dating synchronizes well with the chronology of the most important ritual and ceremonial object within the Chotyniec settlement—the so-called zolnik and other Scythian settlements from the East European forest-steppe zone.
The paper focuses on the Pleistocene deposits in Perspektywiczna Cave, southern Poland, related to cave hyena (Crocuta crocuta). We used direct radiocarbon dating of hyena fossils supported by genetic and stable isotope analyses to infer the paleobiology of this population. Radiocarbon dating of 19 hyena remains suggests long inhabitation of the region during early MIS 3, around 50–34 ky cal BP. The youngest among our dates, 34,355–33,725 cal BP (1σ, combined of two dates for the same specimen) points out the latest appearance of a cave hyena north to Carpathians. Beside this long period of occupation, the Perspektywiczna Cave hyenas stayed ecologically stable, but their genetic structure changed. Two mtDNA haplogroups were present, one typical for other Late Pleistocene European populations and the other one known so far only from recent African populations.
We present atmospheric radiocarbon concentrations in CO2 integrated samples taken between January 2019 and December 2021 in the Mexico City Metropolitan Area (MCMA) and explain the variations in terms of changes in emission sources associated with the COVID-19 lockdown restrictions imposed from March 2020. Δ14C values for samples collected during 2019 range between –44.15‰ and –13.17‰, with lower values during months with higher fossil fuels consumption and air stagnation, whereas higher values were found for periods with high number of fires around MCMA or wet months with higher contribution of heterotrophic respiration. For samples collected during 2020, Δ14C values range between –17.7‰ and 2.25‰, with an increasing trend immediately after the initial lockdown and higher values obtained for samples collected during lockdown phases 2 and 3 and the period of extremely high epidemic risk. This agrees with the 38% and 52% decrease in gasoline and diesel sales. Once essential activities gradually opened from July 2020, Δ14C follow a decreasing trend as vehicle traffic started to increase again. Δ14C values for samples collected during 2021 range from –32.89‰ to –10.27‰, with the higher value obtained during a period of extremely high epidemic risk with a 30% reduction in gasoline and diesel consumption. Despite the complexity of emission sources in MCMA, from Δ14C variations it was possible to identify changes in fossil CO2 emissions resulting from the significant reduction in vehicle traffic due to the COVID-19 lockdown and the restrictions imposed to control transmission of the disease.
A summary of the chronology for the key paleontological and archaeological site of Volchia Griva in the southern part of the West Siberian Plain is presented. Currently, 42 reliable 14C values have been generated on animal bones (37 14C dates) and charcoal (5 14C dates). Three stratigraphic levels of animal bones are established. The 14C ages of the fossils are as follows: the upper level—ca. 10,620–12,520 BP; the middle level—ca. 13,700–17,800 BP; and the lower level—ca. 18,230–19,790 BP. The majority of animal fossils and artifacts are associated with the lower level. Based on the results obtained, we suggest that Upper Paleolithic people occupied the Volchia Griva site during the second part of the Last Glacial Maximum (LGM), ca. 18,200–19,800 BP, and perhaps occasionally afterwards. It is obvious that these humans were well adapted to the cold and dry climate of the LGM, as well as numerous other populations in Siberia south of 58°N. It is noteworthy that the youngest 14C values on woolly mammoth are of ca. 10,620–11,815 BP, and this makes the Volchia Griva one of the latest mammoth refugia in northern Eurasia outside of the Arctic.
The rich architectural heritage of Cyprus from the period of Byzantine and Latin rule includes 10 churches inscribed in the UNESCO World Heritage list. Most of these monuments preserve wooden elements: whether structural, decorative or furnishings. Many preserve wall paintings that are considered among the best examples of Byzantine and Medieval art in the Eastern Mediterranean. The dating of these paintings as well as the church buildings themselves, has been based mainly on style, with occasional dedicatory inscriptions and related historical interpretation. We report early results from a project investigating the wooden cultural heritage of Cyprus and in particular the combined use of dendrochronology with radiocarbon via tree-ring sequenced 14C wiggle-matching to help place initial tree-ring sequences. This includes a floating 264-year Pinus brutia chronology from several monuments, which, with a ca. 5-year gap, suggests prospects for >700-years of P. brutia chronology for Cyprus, and, with one gap of several decades to fill, ca. 1100 years of Pinus nigra chronology for Cyprus. Several currently floating elements from the multi-phase UNESCO-listed Timios Stravros church at Pelendri, including a terminus post quem for the celebrated liturgical wooden cross, are approximately dated across the 11th to 16th centuries AD.