In this study, we investigate the impact of X-rays produced by conventional mCT instruments on fossil materials dated by radiocarbon. Our results clearly show a decrease on the collagen preservation in fossil and modern bones and teeth, and therefore on the radiocarbon analytical results (in particular, the collagen yield and, possibly, stable isotope composition), after mCT scanning. In other words, all the samples analysed here have experienced a noticeable radiation damage, regardless of their nature (bone and dental tissue) and age (modern and fossil). Given these observations, a prudent approach would be for radiocarbon laboratories to expect lower collagen yields for samples that have been previously mCT scanned and ensure appropriately sized standards are processed alongside these samples. Additionally, samples with originally low collagen yields might become unsuitable for radiocarbon dating after mCT or at least show a yield lower than the usual minimum cut-off value. In this case, it might be viable to extend the collagen yield quality assurance parameter for mCT scanned bones and teeth and instead focus on the C:N ratio as the most appropriate indicator of collagen quality, although we cannot exclude that the latter may also be impacted by X-ray exposure. Further investigations on a larger set of samples are required to confirm these first observations. Nevertheless, in the light of these results, we can reasonably conclude by recommending caution regarding the systematic and unlimited use of mCT scanning in palaeoanthropology or in other related disciplines involving fossil material.

The radiocarbon (14C) specific activity was measured in vegetation and atmosphere in Ramnicu Valcea, Romania. On the sampling location operates a nuclear installation, namely “Experimental Pilot for Separation of Tritium and Deuterium” (PESTD), a semi-industrial installation designed for the detritiation of heavy water moderator of CANDU reactors and a 315 MW coal-fired thermoelectric power plant. Because one of the important releases of PESTD is gaseous radioactive effluent, the baseline of radiocarbon was a must for the environmental program. On the other hand, due to the Suess effect, a relative decrease of the radiocarbon-specific activity on a local scale is expected as a result of the dilution of the carbon isotopic mixture by fossil carbon. All the measurements were done by liquid scintillation counting and direct absorption method. It can be observed that the specific activity of 14C was similar for both types of samples investigated. The variations encountered are generally within the limit of uncertainty associated with the 14C. The average radiocarbon-specific activity recorded has the following values: 0.226 ± 0.016 Bq/gC for the vegetation and 0.228 ± 0.016 Bq/gC for the atmosphere. The results have a clear decreasing trend, but due to local influence caused by the continuous production of fossil CO2, cannot be observed 14C seasonal variations. A strong correlation between radiocarbon activity in air and vegetation was highlighted.

In recent years, the increasing accumulation of radiocarbon dating data in Jomon research has progressed, creating a foundation for more detailed chronological estimates of the Jomon period’s high-resolution typo-chronology. However, there remains a gap between relative chronologies based on typology and radiocarbon data. A key issue arises from discrepancies between the concept of keishiki (“type” in Japanese) as a time unit of relative chronology, defined based on production period, and the radiocarbon dates, which reflect various events that occurred to the pottery after its production. To overcome the gap, this study introduced a new Bayesian chronological model, the one-sided sequential model, which sequentially orders only the start boundaries of each typological group. When this model was applied to a case study from the Middle Jomon period in the Kanto region, it estimated more reasonable date ranges for each phase of the typo-chronology than the contiguous model. Additionally, the resulting estimated duration of each pottery type was shorter during periods of higher estimated populations and longer during periods of lower estimated populations, providing new insights into the temporal aspects of Jomon society While Bayesian chronological modeling is not prevalent in Jomon research, appropriate models make it possible to make chronological estimates consistent with the high-resolution Jomon chronology, which is considered to approach a generational scale. Such attempts enable detailed clarification of various social and cultural changes. The temporality of the past thus revealed provides a new approach to a deeper understanding of Jomon society.

Understanding the developmental and occupational histories of Ancestral Maya settlements is crucial for interpreting their roles in broader social, political, and economic dynamics. This article presents 62 new accelerator mass spectrometry (AMS) 14C dates from residential groups in the outlying settlement zone at Alabama, a major inland Ancestral Maya center in East-Central Belize. Alabama is a rare example of a “boomtown” in the Maya lowlands, experiencing rapid development primarily during the 8th and 9th century CE, corresponding to the Late to Terminal Classic periods. Using Bayesian stratigraphic sequence models, we construct detailed developmental and occupational histories for the townsite, clarifying the timing of its development, occupation, and abandonment. Our analysis reveals complex residential histories, confirming a rapid tempo of Late and Terminal Classic settlement growth and indicating continuities in occupation into the 10th century CE and beyond. Furthermore, we identify two separate periods of occupation during the Early Classic (cal AD 345–545) and the Late Postclassic (cal AD 1325–1475), demonstrating that parts of the settlement were inhabited at different intervals over many centuries. These results offer the first detailed deep-history perspective for the East-Central Belize region, establishing a framework that addresses challenges in chronology-building posed by poor pottery preservation and the complexities of earthen-core architecture at the site and enabling future chronological modeling in this lesser-known frontier of the eastern Maya lowlands.

This study presents a series of new radiocarbon dates and the first stable carbon and nitrogen isotope measurements of C3 cereal grains from Roman Iron Age (1–400 AD) archaeobotanical assemblages in Lithuania, southeastern Baltic region. These data are complemented by stable isotope measurements of faunal remains to assess local environmental conditions and evaluate human impact on the landscape through agricultural practices. The δ15N and δ13C values indicate that agriculture during this period relied heavily on intensive manuring and cultivation in open, well-irrigated landscapes. The results also reveal diverse cultivation strategies across sites, with isotopic differences between rye and barley suggesting the possible use of an infield–outfield cultivation system. Radiocarbon dates indicate that these agricultural innovations may have started as early as the 1st to mid-2nd century AD with the introduction of rye, however the evidence points to a gradual and uneven adoption rather than a rapid uniform shift.

During the last decade, early Neolithic sites with unique flat-bottomed pottery as distinguishing feature were discovered in the southern part of Western Siberia at the Baraba forest-steppe and identified as the Early Neolithic Baraba Culture (briefly, Baraba culture). The culture is represented in settlements and ritual complexes, has households, as well as implements made of stone and bone. Samples of mammal bones, bird bones and bone artifacts were collected from three sites of the Baraba Culture: Vengerovo-2, Tartas-1, and Ust-Tartas mounds, and dated by accelerator mass-spectrometry (AMS) to reconstruct the chronology of the sites. 36 reliable radiocarbon dates were obtained: 12 of them at the Curt-Engelhorn-Centre of Archaeometry (Mannheim, Germany) and 24 at the AMS Golden Valley (Novosibirsk, Russia). Minimal-to-no differences between radiocarbon dates assessed at GV and MAMS facilities were identified by Bayesian analysis of covariance/analysis of variance. Bayesian chronological modeling supports existence of the Baraba culture between the middle of 8th millennium BC till the start of 6th millennium BC. Two stages of sites’ use were identified, separated by the transitory period of uncertain duration lasting since the end of 7th millennium. The end of the first stage was followed by abandonment of the Tartas-1 site, which we suggest coincided with the start of the 8.2k climatic event.1

Plague and famine are two of the worst killers in human history. Both struck the Czech lands in the Middle Ages not long after each other (the famine of 1318 CE and the plague of 1348–1350 CE). The aim of our study was to try to relate the mass graves found in the vicinity of the Chapel of All Saints with an ossuary in the Kutná Hora–Sedlec site to these two specific events. For this purpose, we used stratigraphic and archaeological data, radiocarbon dating, and Bayesian modeling of 172 calibrated AMS ages obtained from teeth and bones of 86 individuals buried in the mass graves. Based on the stratigraphic and archaeological data, five mass graves were interpreted as famine graves and eight mass graves were interpreted as plague graves. Using these data and the calibration of the radiocarbon results of the tooth-bone pairs of each individual, we constructed the Bayesian model to interpret the remaining mass graves for which no contextual information was available (eight mass graves). In terms of Bayesian model results, the model fits stratigraphic data in 23 out of 34 cases and in all seven cases based on calibration data. To validate the model results on archaeologically and stratigraphically uninterpreted data, ancient DNA analysis is required to identify Yersinia pestis.

Measurements of the radiocarbon (14C) content of subannual wood cellulose samples over the 1963 bomb spike have revealed an apparent delay between the increase in atmospheric radiocarbon content and that of wood cellulose. This delay is apparent in both coniferous and deciduous tree species and is of a magnitude of approximately 4 weeks. The delay in wood cellulose 14C change as measured in a Sitka spruce from Washington state, USA, was previously used to estimate the relative influence of tree physiological effects contra environmental effects. We repeated the measurements with the increased measurement precision of today’s AMS systems and compare the new results to the ones of a Scots pine tree from Trondheim, central Norway and a white oak from Oregon state, USA. The results challenge the assumption that the 14C tree ring records directly show the atmospheric 14C concentration of a homogeneous, zonally well-mixed atmosphere. Instead, the apparent 1963 delay reflects local influences of the ecosystem and tree physiology. The 1963/1964 data allows for exploratory modeling of the effects of biospheric decay CO2 and local environmental influences assuming the absence of stored photosynthates from the previous year. Compared to the 10–30% contribution from biospheric CO2, the effects of delayed incorporation of carbon into the wood cellulose and the effect of stored photosynthate are small in the conifers. Highly detailed 14C records of stem cellulose can, in combination with stable isotope studies, contribute to our understanding of variability of the local carbon cycle, climate, and the environment.

The cycling of carbon in riverine systems is a critical component of global carbon cycle research. However, the sources and performances of riverine carbon in the Qinling Mountains, a pivotal hydrological nexus in China, remain poorly understood. This study investigates the seasonal variations of dissolved organic carbon (DOC) concentration in the Tianyu River within the Qinling Mountains. By utilizing a combination of carbon isotopic signatures (Δ14C-δ13C) and the stepped-combustion method, we examined the sources of DOC and the contribution ratio of each end-member. Our findings reveal that: (1) the concentrations and dual carbon isotope ratios of DOC in the Tianyu River are influenced by regional climatic factors, exhibiting distinct seasonal patterns; (2) the 14C age of DOC in the Tianyu River is comparatively older than the global average for rivers but younger than that of China’s three major rivers (the Yellow, Yangtze, and Pearl Rivers); and (3) the DOC mainly comes from exogenous sources, with a proportion of about 85.8%–88.4%. Vegetation and riverine sediments are identified as primary contributors. These findings suggest that exemplary ecological preservation exists within the Qinling region while operating within an efficient carbon cycling system. This investigation provides initial insights into how regional climatic conditions influence riverine carbon cycles and enhances our understanding of biogeochemical processes related to carbon.

The site of Stublina, first excavated in 1956 by Milutin Garašanin of the Institute of Archaeology and Radoslav Galović of the National Museum Belgrade is located at the southeast outskirts of the Supska village near the town of Ćurpija, in Central Serbia. Its location on the edge of the flood plain of the Central Balkans’ major waterway, the Velika Morava River, places it on a major corridor extending south to north, linking southern Europe and the Aegean with the Pannonian plains in the north. Based on material finds, the site predominantly belongs to the Late Neolithic and is attributable to the so-called Vinča culture complex; however, sporadic finds of Early Neolithic Starčevo type pottery and Late Medieval burials were also reported. The results of the excavation were published in a single monograph in 1979, containing information on roughly half of the excavated area. However, radiocarbon dating was never performed on the site. The site of Stublina, containing evidence for the life span of the so-called Vinča culture complex in the Velika Morava River basin, one of the most important corridors during the entire Neolithic period of Southeast Europe, is a valuable chronological beacon based on its vast material record of pottery fragments, traditionally used to construct relative chronological sequences in the past. In this paper, we present the results of contextual radiocarbon dating using Bayesian chronological modeling with 28 new AMS 14C radiocarbon dates, selected from the material archive located in the depos of the National Museum of Serbia in Belgrade. The samples were chosen from stratigraphically well-defined contexts published in the 1979 Garašanin and Garašanin volume on Supska. These contexts provide secure chronological order of layers and features, representing the entire life span of the site in the Late Neolithic period. Our results provide strong validation for archival records originating from old archaeological excavations and breathe new life into their potential for contemporary archaeological research, using techniques and methods unavailable at the time of their creation.