This paper presents new radiocarbon dates for two Aboriginal archaeological complexes situated on the cliff-lines of the Murray River in South Australia (SA); at Pooginook Flat and Tanamee. These dates represent the first age estimates for archaeological sites within the Upper Gorge section of the Murray River. The dates ranged from ca. 11 cal ka to the Late Holocene. The research supports previous evidence which has indicated that sites located along the Murray cliffs preserve much of the oldest evidence of Aboriginal peopling along the Murray River corridor in SA. The new dates also allow us to contribute to discussions concerning broader chronological trends in Aboriginal lifeways within the Murray-Darling Basin (MDB). Specifically, the new ages add some insight into the nature and timing of early Aboriginal occupation along the Murray River corridor in SA and further evidence that the LGM acted as a significant inhibitive factor for intensive occupation of this riverscape. The conservation of these significant and informative cliff-top sites remains precarious, however, and there is an imperative to continue to record and sample the extant sites.

This study aims to discuss the chronology of the Egyptian 5th dynasty of the Old Kingdom and the tentative date of accession of king Djedkare based on material from his royal necropolis at South Saqqara and non-royal cemetery of Abusir South, Egypt. A series of radiocarbon (14C) dates were established through analysis of archaeological material from several monuments at the necropolis, including the king’s pyramid complex, pyramid complex of his queen, and two elite tombs (Isesiankh and Khuwy). In addition, two samples from non-royal tombs in the Abusir South cemetery, were taken into consideration for further precision during the modeling, associated with king Huni (end 3rd dynasty) and king Niuserre (5th dynasty). The contextualized 14C dates together with re-evaluation of historical evidence on Djedkare’s rule, results in a new model of temporal probability density which can be further refined with any new data from archaeological research. It shows that Djedkare’s reign can be currently modelled between 2503 and 2449 BCE (95.4%), thus slightly older than expected by literature. This presented model provides a more precise chronological frame for the late 5th dynasty period of Egyptian history, which was period of a significant socio-economic transformation.

To investigate long-term relationships between climate, vegetation, landscape geochemistry and fires in the boreal forest zone of Western Siberia, a sediment core of 345 cm was collected from Shchuchye Lake (located in south taiga zone of southeast part of West Siberian plain) and investigated by spore-pollen, radiocarbon, LOI and charcoal analyses. Quantitative palaeoclimate was reconstructed based on pollen data. Investigation revealed 13.2 cal ka history of vegetation, climate, landscapes and fires. In the dry climate of Late Glacial, the landscape was treeless. Continuous permafrost existed in the soil. In the middle of the YD cooling 12.4–12.2 cal ka BP, our data showed warming that caused degradation of permafrost in soils and settlement of spruce in moist places. Later, thawing and accumulation of moisture in a local lowering in relief increased and a lake was formed. With the beginning of the Holocene, the climate sharply changed to warmer and wetter. Intensified surface flow caused accumulation of mineral and carbonate fraction in the lake. Dense birch forests spread on drylands. As a result, the leaching regime initiated the formation of podzols in the soil. At about 10.0 cal ka BP, Scots pine (Pinus sylvestris) quickly spread in the area of investigation. Fires became more frequent and more intense during the dry Late Glacial time, sharply decreasing with increased precipitation in the Early Holocene, and again moderately increasing with spread of pine forests in the mid Holocene. With the transition to Late Holocene (after 6.0 cal ka BP), the intensity of regional background fires and number of local fires decreased.

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.

Despite chronicles from the 16th century describing fertile alluvial plains and densely populated wetlands, archaeology in western Mexico has been little studied. The Directorate of Archaeological Salvage (DSA) of National Institute of Anthropology and History (INAH) has initiated a study of two sites in Costa Canuva, at the southern part of Nayarit state: Becerros and Naranjos. Thirty charcoal and shell samples were radiocarbon (14C) dated to determine occupation history. A Bayesian approach was used to build a chronological modeling from charcoal samples. Charcoal and shell samples found in the same context allowed us to calculate the ΔR values of marine offset for this period. In general, the archaeological sites of this area are divided into three major periods: Formative, Classic, and Postclassic. The 14C dating of Becerros recovered materials provided a chronological framework for the site’s occupation, from cal AD 169–1025, corroborating the ceramic studies in the sense that human settlement activities date from the Formative (300 BC–AD 600) to the Early Postclassic (AD 900–1200). Naranjos started in the Classic period and reached its occupancy peak in the Late Classic. The site’s occupation may have persisted for at least two centuries after the conquest of the Altiplano in 1521. The comparison of charcoal dates and associated shell samples from the Naranjos Unit gave a probability distribution for ΔR, that ranged from 118.5 to 199.5 with a mean value of 159 ± 4, slightly higher than other values obtained at nearby sites.

In order to better characterise carbonaceous components in atmospheric aerosols and to assess the contributions of fossil carbon (FC) and non-fossil carbon (NFC) sources and their seasonality in the Eastern Mediterranean, we collected fine (PM1.3) aerosols at a remote marine background site, the Finokalia Research Station, Crete, Greece, over a period of one-year. PM1.3 samples were analysed for elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC), and stable carbon isotope ratio (δ13CTC) and radiocarbon content (14CTC) (pMC) of total carbon (TC). All the parameters, i.e., PM1.3, δ13CTC and 14CTC showed a clear temporal pattern with higher values in summer and lower values in autumn. The 14CTC ranged from 54.7 to 99.1 pMC with an average of 74.5 pMC during the entire year. The FC content in TC (FCTC) was found to be slightly lower in winter and almost stable in other seasons, whereas the NFC contents (NFCTC) showed a clear seasonality with the highest level in summer followed by spring and the lowest level in winter. Based on these results together with the seasonal distributions of organic tracers, we found that biomass burning (BB) and soil dust are two major sources of the fine aerosols in winter. Although biogenic emissions of VOCs followed by subsequent secondary oxidation processes are significant in summer followed by spring and autumn, pollen is a significant contributor to TC in spring. This study showed that emissions from fossil fuel combustion are significant (25.5%) but minor compared to NFC sources in the eastern Mediterranean.

The Second International Mortar Dating Intercomparison Study (MODIS2) took place in 2020. Three mortar samples from different sites and chronologies were distributed among various research groups in form of bulk mortar and grain fraction smaller than 150 µm. This is the first time the Zagreb Radiocarbon Laboratory, with support of the Center of Applied Isotope Studies, University of Georgia, took part in the international mortar intercomparison. The initial approach of the Laboratory to mortar dating was to separate 32–63 µm grain fraction and collect three CO2 gas portions by sequential dissolution with acid. After checking the 14C date trends of the gas portions, which should be ascending with later fractions, the one for the first and shortest gas portion was reported as the age of the mortar. However, the first gas portion might not be true age of the mortar, since it still might contain some “dead” carbon. Therefore, data extrapolation from the first two initial CO2 portions was also conducted on the results, but not reported to the intercomparison. Though in general, all the intercomparison reported dates fit the expected historical ages, for one sample, the extrapolated result showed a better match to the historical data.

We present the excavation results from a Middle Neolithic site associated with the Funnel Beaker Culture. Within two overlying house phases, a recessed area was recorded, which had been constructed using different sized pebbles. The arrangement and form of the feature clearly indicated anthropogenic origin and is understood as belonging to one of the house phases. Consequently, it is interpreted as a cellar. Several pits and post holes are additional features that were recorded at the site and indicate the presence of a fence structure with up to seven parallel courses. In this paper, we present radiocarbon dates from the features and an age model for the construction and use of the cellar as well as the fences. Moreover, the site Nygårdsvej 3 will be placed in its regional archaeological landscape.

This brief review describes the discovery of cosmic rays by Victor Hess from the Vienna Radium Institute and the later contribution of Marietta Blau through her observation of “disintegration stars” in photographic emulsion plates exposed to cosmic-ray bombardment. Marietta Blau, a nearly forgotten cosmic-ray pioneer from the Vienna Radium Institute, developed the nuclear emulsion technique for studying nuclear reactions, eventually discovering the disintegration of nuclei through high-energy cosmic rays. Blau survived the Holocaust by escaping to Mexico City from 1939 to 1944. Starting in 1948 at Columbia University, later as a staff member of Brookhaven National Laboratory and then University of Miami, she performed fundamental and original research with nuclear emulsions exposed to 3-GeV protons at the Brookhaven Cosmotron and to 6-GeV protons at the Berkeley Bevatron. Blau returned to Vienna in 1960, where at the Radium Institute a classical β-decay counting facility for radiocarbon dating had been installed, which was finally superseded by the Vienna Environmental Research Accelerator (VERA), a modern versatile accelerator mass spectrometry facility.

In 2015, a new accelerator mass spectrometry facility (AMS), the ECHoMICADAS (Environnement, Climat, Homme, MIni CArbon DAting System), was installed in the Laboratoire des Sciences du Climat et de l’Environnement (LSCE). Equipped with a hybrid source, it allows the analysis of solid or gas samples for 14C measurement. Here, we summarize the equipment surrounding the Gas Interface System (GIS), namely the elemental analyzer (EA), the carbonate handling system (CHS2) and the ampoule cracker. We describe our model of sample contamination, taking into account the cross and the constant contaminations, and then describe how these contaminations were handled in the data processing. Both contaminant corrections are applied before the phases of blank subtraction and standard normalization, making it possible to use the standard, blank and sample ratios without contaminant during these phases. We finally present our results on normalization standards (N=118), blanks (N=125) and reference materials (N=117) for different measurement protocols and for sample masses between 3 and 300 µgC.

As a required sample preparation method for 14C graphite, the Zn-Fe reduction method has been widely used in various laboratories. However, there is still insufficient research to improve the efficiency of graphite synthesis, reduce modern carbon contamination, and test other condition methodologies at Guangxi Normal University (GXNU). In this work, the experimental parameters, such as the reduction temperature, reaction time, reagent dose, Fe powder pretreatment, and other factors, in the Zn-Fe flame sealing reduction method for 14C graphite samples were explored and determined. The background induced by the sample preparation process was (2.06 ± 0.55) × 10–15, while the 12C– beam current were better than 40μA. The results provide essential instructions for preparing 14C graphite of ∼1 mg at the GXNU lab and technical support for the development of 14C dating and tracing, contributing to biology and environmental science.

This work presents the integration of an elemental analyzer (EA) and an isotope ratio mass spectrometer (IRMS) into the 6 MV AMS system at the Institute for Nuclear Physics, University of Cologne. The AMS measurement of δ13C values for IAEA-C6 reference material resulted in –11.39(226)‰, compared to –10.28(32)‰ obtained by IRMS. The EA-IRMS system was also tested with IAEA-C3, IAEA-C5, and IAEA-C7 reference materials, yielding –24.79(9), –25.18(15), and –14.76(18)‰ respectively. Compared to the IAEA information values given as –24.91(49), –25.49(72) and –14.48(21)‰ respectively. To investigate an observed sample mass dependency, environmental samples from Spitzbergen were examined, showing δ13C values of –25.17(55), –25.80(31), and –26.17‰ in Cologne, while Hamburg recorded –24.8(1), –25.5(1), and –26.2(13)‰. In summary, this new setup could enable online analysis and quasi-simultaneous measurements of 14C, δ13C, and δ15N for ultra-small samples, utilizing precise δ13C values from IRMS for fractionation correction of the 14C/14C isotopic ratio.

Yakushima is a small, mountainous island off southern Kyushu, Japan. Its proximity to active volcanos and subduction zones leaves Yakushima vulnerable to large megathrust earthquakes and tsunamis, in addition to powerful typhoons and storm surges. These hazardous events deposit beach boulders: large rocks moved above sea-level by powerful waves. By radiocarbon dating the fossilized coral within these boulders, one can derive age estimates of the hazard events. Reliably estimating the magnitude and timing of geological events in the historical record is vital for future hazard prediction and mitigation. In this study, we estimated the deposition age of ten boulders on the north coast of Yakushima to infer potential paleo tsunamis and storm surges. We found that large wave events have occurred frequently throughout the Holocene. Based on the boulders’ ages, we identified four potential deposition events at 1986–2692 cal yr BP, 3522–4075 cal yr BP, 4773–5232 cal yr BP, and 6187–6638 cal yr BP. These deposits are likely a result of storm surges, or tsunamis from nearby volcanic activity or subduction earthquakes. Another set of boulders dated to 5125–5738 cal yr BP were likely exposed due to a decline in sea-level following the Holocene high sea-level stand. Further modelling could determine the wave height necessary to move the boulders and distinguish between storm and tsunami deposits. This is especially pertinent given the high frequency of coastal geohazards, and the likelihood of similar hazards impacting southeast Japan in the future.

The newly designed HVE gas interface enables the AMS measurement of carbon samples in CO2 form. The CO2, e.g. resulting from the sample combustion in an elemental analyzer, is adsorbed in a zeolite trap and subsequently transferred to a motor-driven syringe. Once diluted with He, the gas mixture is transferred into the ion source of the AMS system. A carbon ion beam is formed in the ion source and mass-analyzed by the AMS system, resulting in 13C/12C and 14C/12C isotopic ratios. The HVE gas interface features two traps and two syringes to maximize the sample throughput, which results in more than 10 samples per hour. The first performance results of CO2 gas sample AMS measurements that were performed with the HVE gas interface in combination with the HVE 210 kV AMS system are presented in this paper. The measurements show that the gas interface contribution to the 14C/12C background is in the 10–15 level and to the precision is at or below 1%.

The dietary habits of Neanderthals are considered an issue of great interest in the literature and have opened an important number of fruitful debates. Indeed, understanding diets can provide important information regarding issues of palaeoenvironmental reconstructions and subsistence strategies. In this respect, dental remains can play a vital role in the conducted efforts to reconstruct the palaeoecological niches securely and accurately since dental microwear analyses have precisely detected dietary patterns of the populations in the past. In this context, the Iberian Peninsula forms an interesting model for examining Neanderthal populations, their subsistence strategies, and adaptive skills. This study aims the examination of already published data in order to provide a holistic approach regarding the dietary habits of H. neanderthalensis populations in the Iberian Peninsula, along with the importance of the utilization of dental microwear analysis in the archaeological record.

Studies with multiple radiocarbon dates often contain useful information on the relative locations of the dated levels. Such information can be used to obtain robust, integrated site chronologies, with at times more precise ages than those of the individual dates, where outliers can be identified and downweighted, and where the ages of any undated levels can also be estimated. Examples include trees with radiocarbon dates separated by exactly known amounts of yearly tree-rings, or sedimentary sites where ages further down the stratigraphy can be assumed to be older than ages further up. Here we present coffee, an R package for Bayesian models that apply chronological ordering for fossils and environmental events. Coffee runs natively within the popular and versatile R environment, with no need for importing or exporting data or code from other programs, and works with plain-text input files that are relatively easy to read and write. It thus provides a new, transparent and adaptable educational and research platform designed to make chronology building more accessible.

Cellulose of tree rings is often assumed to be predominantly formed by direct assimilation of CO2 by photosynthesis and consequently can be used to reconstruct past atmospheric 14C concentrations at annual resolution. Yet little is known about the extent and the age of stored carbon from previous years used in addition to the direct assimilation in tree rings. Here, we studied 14C in earlywood and latewood cellulose of four different species (oak, pine, larch and spruce), which are commonly used for radiocarbon calibration and dating. These trees were still growing during the radiocarbon bomb peak period (1958–1972). We compared cellulose 14C measured in tree-ring subdivisions with the atmospheric 14C corresponding to the time of ring formation. We observed that cellulose 14C carried up to about 50% of the atmospheric 14C signal from the previous 1–2 years only in the earlywood of oak, whereas in conifers it was up to 20% in the earlywood and in the case of spruce also in the latewood. The bias in using the full ring of trees growing in a temperate oceanic climate to estimate atmospheric 14C concentration might be minimal considering that earlywood has a low mass contribution and that the variability in atmospheric 14C over a few years is usually less than 3‰.

Illegal poaching brought elephant species to the brink of extinction; therefore, international trade in ivory has become regulated by the Convention on International Trade in Endangered Species of Flora and Fauna (CITES). However, the trade is still allowed for antique items, standing for ivory from a period before 1947 within the European Union. This could serve as a loophole for the laundering of modern ivory. In the described case of the Happy Fisherman statuette, the traded item was declared to be antique, but radiocarbon analysis proved a modern provenance, and the statuette was confiscated. The radiocarbon analysis was later confirmed by information from a Chinese newspaper found inside the statuette. Based on the findings, we strongly recommend careful consideration of each individual ivory piece offered for sale, with a thorough inspection of the items and related documentation carried out by a relevant CITES authority. Any exemption of the commercial ban should be granted only to those applicants who meet the criteria of proper evidence in the form of scientific analysis or reliable and trustworthy documentation.

A new vacuum line to extract CO2 from carbonate and dissolved inorganic carbon (DIC) in water was established at Guangxi Normal University. The vacuum line consisted of two main components: a CO2 bubble circulation region and a CO2 purification collection region, both of which were made of quartz glass and metal pipelines. To validate its reliability, a series of carbonate samples were prepared using this system. The total recovery rate of CO2 extraction and graphitization exceeded 80%. Furthermore, the carbon content in calcium carbonate exhibited a linear relationship with the CO2 pressure within the system, demonstrating its stability and reliability. The system was also employed to prepare and analyze various samples, including calcium carbonate blanks, foraminiferal, shell, groundwater, and subsurface oil-water samples. The accelerator mass spectrometry (AMS) results indicated that the average beam current for 12C- in the samples exceeded 40 μA. Additionally, the contamination introduced during the liquid sample preparation process was approximately (1.77 ± 0.57) × 10−14. Overall, the graphitized preparation system for carbonate and DIC in water exhibited high efficiency and recovery, meeting the requirements for samples dating back to approximately 30,000 years.

Polycyclic aromatic hydrocarbons (PAHs) are major air pollutants that are ubiquitously produced by the combustion of organic materials, and it is extremely important to identify their pollution sources. In this study, molecular fingerprinting and compound class-specific radiocarbon dating (CCSRA) were performed on PAHs from canal sediments and air samples collected in Kolkata, India’s third largest city (population approximately 16 million), where PAHs pollution has been a serious problem. Average PAH (Σ12-parent PAHs) concentrations in air samples were 65.1 ng m–3 in summer and 70.9 ng m–3 in winter and in canal sediments were 32.7 µg g–1, which are classified as “very high-level” pollution. Molecular fingerprinting using methyl-PAH/PAH (MPAHs/PAHs) ratios and isomer pair ratios with molecular weights of 178, 202, 228, and 276 suggested that wood and coal combustion were the dominant sources of PAHs in the sediment, and that atmospheric PAHs were influenced by oil combustion in addition to them. The fraction of contemporary carbon (ƒC) of sedimentary PAHs (0.056–0.100), together with the extremely low MPAHs/PAHs ratio results, lead to the conclusion that the major source of the high concentration of PAHs in the canals is from coal combustion. On the other hand, the ƒC of atmospheric PAHs (0.272–0.369) was close to the share of biomass fuels in India’s domestic fuel consumption in 2011 (about 35%). Furthermore, the observed ƒC-discrepancy between atmospheric and sedimentary PAHs in the same urban environment was interpreted to give an insight into the loading pathway of PAHs to canal sediments in Kolkata.