Prehistoric shell mounds can be useful for the quantification of the radiocarbon marine reservoir effect (MRE) and, at the same time, knowledge about the MRE allows for the establishment of robust chronologies for these sites. This creates a loop in which the archaeological setting has a dual role: it is part of both the method and the application. Therefore, it is paramount to address these sites from both archaeological and environmental perspectives, investigating their origin and diagenesis in order to overcome biases caused by post-depositional alterations. In this study, samples of bone, charcoal and shell from a Late Holocene shell mound in Southern Brazil, the Sambaqui de Cabeçuda, were analyzed following a multidisciplinary approach to disentangle the complex relationships between archaeology and the environment. We performed X-ray diffraction, radiocarbon dating, stable isotopes (δ13C, δ18O, δ15N) and anthracology analyses as well as Bayesian Chronological Models and Isotope Mixing Models to assess the local MRE and to reconstruct the diet of Cabeçuda builders. Our results reveal a negative local correction for the MRE (ΔR = –263 ± 46 14C yr), expected for the lagoon next to the site, and diets with considerable intakes of marine proteins. We examine the implications of these results for the chronology of the site and discuss a series of complications when performing MRE studies using shell mound sites.

The carbon isotope distribution and its relationship with stable N and S isotope ratio values were investigated within a fish assemblage from the shallow lake Tapeliai, which is constantly affected by inflows of 14C depleted water from the surrounding watershed mires. The “conventional” radiocarbon age within the fish from this lake varied from 119 to 693 yr. The 14C/12C and δ13C values correlated significantly (r=0.85 p<0.001), which is not typical in lakes of the temperate zone. There were no observed statistical differences (Kruskal–Wallis ANOVA tests) in the 14C/12C values among different fish species. The radiocarbon dating values and 15N/14N measurements did not correlate. The radiocarbon measurement values also did not correlate with δ34S, however, the distribution of these isotopes in carp (119 yr and 1.3‰, respectively) and roach (344 yr and 4.5‰, respectively) indicated that fish may include allochthonous food sources in their diet.

Since 2018, the radiocarbon laboratory of Lanzhou University has been equipped with a compact accelerator mass spectrometer—a 200-KV mini carbon dating system (MICADAS), together with an auto graphitization equipment (AGE III). The laboratory has for a long time prepared graphite targets for 14C dating of plant fossils, charcoal, bones, and bulk organic matter. Herein, we give an overview of the operating status and performance of the dating facility. The long-term measurements of the standard and blank samples indicated that the results for MICADAS in Lanzhou University were accurate and stable and of high sensitivity. Fifteen sets of organic materials collected from archaeological sites in northwest China were selected for an inter-comparison study involving the participation of four specialist laboratories. The 14C dating results for the homogenized archaeological samples from several of the laboratories showed a high degree of consensus. The long-term performance and inter-comparison data for MICADAS confirmed that the radiocarbon laboratory of Lanzhou University could provide stable and accurate 14C dating results. In this context, the 14C dating results for a number of key archaeological/environmental samples were validated.

The Final Neolithic and the Bronze Age (3000–800 BC) are periods of great transformations in the communities inhabiting the area of modern-day Belgium, as testified by archaeological evidence showing an increasing complexity in social structure, technological transformations, and large-scale contacts. By combining 599 available radiocarbon dates with 88 new 14C dates from 23 from funerary sites, this paper uses kernel density estimates to model the temporality in the use of inhumation vs. cremation burials, cremation deposits in barrows vs. flat graves, and cremation grave types. Additionally, by including 78 dates from settlements, changes in population dynamics were reconstructed. The results suggest a phase of demographic contraction around ca. 2200–1800 BC highlighted by a lack of dates from both settlements and funerary contexts, followed by an increase in the Middle Bronze Age, with the coexistence of cremation deposits in barrows and, in a lower number, in flat graves. At the end of the 14th–13th century BC, an episode of cultural change with the almost generalized use of flat graves over barrows is observed. Regional differentiations in the funerary practices and the simultaneous use of different grave types characterize the Late Bronze Age.

Quantifying the marine radiocarbon reservoir effect, offsets (ΔR), and ΔR variability over time is critical to improving dating estimates of marine samples while also providing a proxy of water mass dynamics. In the northeastern Pacific, where no high-resolution time series of ΔR has yet been established, we sampled radiocarbon (14C) from exactly dated growth increments in a multicentennial chronology of the long-lived bivalve, Pacific geoduck (Paneopea generosa) at the Tree Nob site, coastal British Columbia, Canada. Samples were taken at approximately decadal time intervals from 1725 CE to 1920 CE and indicate average ΔR values of 256 ± 22 years (1σ) consistent with existing discrete estimates. Temporal variability in ΔR is small relative to analogous Atlantic records except for an unusually old-water event, 1802–1812. The correlation between ΔR and sea surface temperature (SST) reconstructed from geoduck increment width is weakly significant (r2 = .29, p = .03), indicating warm water is generally old, when the 1802–1812 interval is excluded. This interval contains the oldest (–2.1σ) anomaly, and that is coincident with the coldest (–2.7σ) anomalies of the temperature reconstruction. An additional 32 14C values spanning 1952–1980 were detrended using a northeastern Pacific bomb pulse curve. Significant positive correlations were identified between the detrended 14C data and annual El Niño Southern Oscillation (ENSO) and summer SST such that cooler conditions are associated with older water. Thus, 14C is generally relatively stable with weak, potentially inconsistent associations to climate variables, but capable of infrequent excursions as illustrated by the unusually cold, old-water 1802–1812 interval.

Politiko-Troullia has generated the largest radiocarbon (14C) dataset from a Prehistoric Bronze Age settlement on Cyprus. We present Bayesian modeling of 25 calibrated AMS ages, which contributes to an emerging multi-site 14C chronology for Cyprus covering most of the Prehistoric Bronze Age. Our analysis places the six stratified phases of occupation at Troullia between about 2050 and 1850 cal BCE, in contrast to a longer estimated occupation inferred from pottery analysis. We provide a rare 14C determination for the transition from Prehistoric Bronze Age 1 to 2 just after 2000 cal BCE, associated with a major architectural dislocation at Politiko-Troullia in response to local landscape erosion, possibly due to increased regional precipitation. We present a regional 14C model for Prehistoric Bronze Age Cyprus combining the chronology for Politiko-Troullia with modeled 14C ages from Sotira Kaminoudhia and Marki Alonia, which is bolstered by individual ages from five other settlements on Cyprus. Through the Prehistoric Bronze Age, agrarian villages on Cyprus developed the foundations for the emergence of urbanized settlement and society during the ensuing Protohistoric Bronze Age. Politiko-Troullia, in conjunction with other key settlements on Cyprus, provides a significant independent contribution to increasingly robust Bronze Age 14C chronologies in the Eastern Mediterranean.

Reliable radiocarbon (14C) ages of foraminifera are a prerequisite to generate robust high-resolution age-depth models or to obtain precise understanding of past carbon cycle dynamics. With the advance of small-scale 14C measurements, instrumental precision and levels of contamination (extraneous carbon introduced during sample pretreatment or analysis) became increasingly important to consider. To reduce the effect of carbon contamination, an attempt can be made to remove it by leaching the surface with weak acids. Alternatively, mathematical corrections (e.g., subtraction) based on processing blanks can be applied. We report on 14C analyses of monospecific foraminifera samples compared between different blank corrections (correction against 14C-free CO2, IAEA-C1 and foraminifera) and sample treatments (i) to examine whether chemical pretreatment and mathematical blank subtraction are comparable, and (ii) to determine limitations hindering reliable 14C dating with ever smaller sample sizes. The data show that chemical pretreatment of foraminifera corrected against IAEA-C1 does remove surface contamination and that the same effect can be achieved for untreated samples that were mathematically corrected for blank values determined from sample size-matched 14C-free foraminifera. Leaching only has a beneficial effect on 14C data for older samples, where the isotopic difference between untreated and chemically pretreated samples exceeds the analytical precision.

The article presents the results of research on the absolute chronology of the Nižná Myšľa cemetery. Due to its scale and location in a key region of the Carpathian Basin, it should be considered one of the most important Early Bronze Age sites in Central Europe. Many years of archaeological research have so far failed to provide adequate data on absolute chronology. This text presents the results of statistical and spatial analyses on a series of newly acquired 14C dates. They allowed us to present a model of the spatial and chronological development of the funerary space and to capture the stage of significant cultural change associated with the adoption of a new raw material—bronze.

The Fragmenta membranea manuscript fragment collection at the National Library of Finland has proved challenging to date using only traditional paleography. Therefore, radiocarbon dates can contribute to the understanding of these fragments by offering a parallel natural scientific timeline for the parchment the manuscripts are written on. In this study, we apply our previously developed method for radiocarbon dating medieval manuscripts made of parchment. In total 35 datings were made from 14 separate assemblages of manuscripts, being the first systematic wide-scale application of radiocarbon dating to a collection of medieval manuscripts in order to improve their chronological proxy. Additionally, due to the fragmentary and sometimes poor condition of the manuscript fragments of Fragmenta membranea analyzed in this study, we used Fourier-transform infrared spectroscopy (FTIR) to evaluate the quality of the collagen and the presence of contaminants in the fragments affecting the radiocarbon dates. We report out radiocarbon dating results and FTIR screenings for each sample and for each manuscript assemblage, and discuss the applicability of our method in further studies of applying radiocarbon dating on objects of cultural historical interest and value. The results indicate an essential role of high-quality samples and multiple measurements to interpret the radiocarbon dating results.

Archival charcoal tree-ring segments from the Mississippian center of Kincaid Mounds provide chronometric information for the history of this important site. However, charcoal recovered from Kincaid was originally treated with a paraffin consolidant, a once common practice in American archaeology. This paper presents data on the efficacy of a solvent pretreatment protocol and new wiggle-matched 14C dates from the largest mound (Mound 10) at Kincaid. FTIR and 14C analysis on known-age charcoal intentionally contaminated with paraffin, as well as archaeological material, show that a chloroform pretreatment is effective at removing paraffin contamination. Wiggle-matched cutting dates from the final construction episodes on Mound 10 at Kincaid, indicate that the mound was used in the late 1300s with the construction of a unique structure on the apex occurring around 1390. This study demonstrates the potential for museum collections of archaeological charcoal to contribute high-resolution chronological information despite past conservation practices that complicate 14C dating.

Radiocarbon (14C) in natural samples undergoes changes due to variations in atmospheric CO2 resulting from anthropogenic activities. To analyze the variation of the 14C ratio in atmospheric CO2, deciduous tree leaves were collected in Gyeongju, a popular tourist city in South Korea. Leaf samples were collected from Prunus subg. Cerasus trees at five different sampling points throughout the city over 3 years (2018, 2020, and 2021). The 14C data of the samples were categorized into three groups (downtown, rural, and tourist sites) and analyzed for variations among the different years. The 14C ratio at downtown sites was stable after 2018, the rural site ratio increased between 2018 and 2020 and then decreased between 2020 and 2021, and the tourist site ratio increased after 2018. We theorize that the increased 14C ratio at the tourist site was caused by a decrease in tourism after 2018.

The possibility to conduct new fieldwork projects in previously largely unexplored Iraqi Kurdistan during the past decade has reinvigorated research into the transformative fifth to third millennium BCE (Chalcolithic to Early Bronze Age) in southwest Asia when human societies grew from small, autonomous villages to centralized states with urban centers. Major efforts to synchronize stratigraphic sequences from various sites in order to reach a consensus on archaeological periodization and to identify the absolute chronology of societal transformations necessarily focused on available datasets from Syria, Turkey, and Iran. However, increased understanding of differences in communities’ adoption, adaptation, or rejection of new forms of technologies and social organization demands the need for constructing region-specific absolute chronological models for comparative analysis. Such work is particularly challenging in the case of Iraqi Kurdistan where sites frequently have major hiatuses in occupation. The site of Kani Shaie (Sulaymaniyah Governorate) offers the rare opportunity to investigate the Chalcolithic to Early Bronze Age with a largely uninterrupted sequence of occupation from ca. 5500 to 2500 BCE. This paper presents a series of fourteen radiocarbon dates, representing every archaeological period in this timeframe, as a first step toward the construction of a regional absolute chronology.

Here, we present the results of carbon isotope and elemental analysis of one-year-old Pinus Sylvestris L. needles collected in 2021 from 10 sampling sites in a highly populated and industrialized area of Poland. The needles were exposed to air pollution for one year. The chemical analysis of the samples was performed using different methods: radiocarbon analysis by accelerator mass spectrometry, stable isotope analysis using isotope ratio mass spectrometry, and elemental analysis by inductively coupled plasma-atomic emission spectroscopy. Variations in the carbon isotopes and elemental composition of pine needles were due to a mixture of carbon dioxide originating from different sources such as households, vehicle traffic, and industrial factories.

Radiocarbon (14C) concentrations in the oceans are different from those in the atmosphere. Understanding these ocean-atmospheric 14C differences is important both to estimate the calendar ages of samples which obtained their 14C in the marine environment, and to investigate the carbon cycle. The Marine20 radiocarbon age calibration curve is created to address these dual aims by providing a global-scale surface ocean record of radiocarbon from 55,000–0 cal yr BP that accounts for the smoothed response of the ocean to variations in atmospheric 14C production rates and factors out the effect of known changes in global-scale palaeoclimatic variables. The curve also serves as a baseline to study regional oceanic 14C variation. Marine20 offers substantial improvements over the previous Marine13 curve. In response to community questions, we provide a short intuitive guide, intended for the lay-reader, on the construction and use of the Marine20 calibration curve. We describe the choices behind the making of Marine20, as well as the similarities and differences compared with the earlier Marine calibration curves. We also describe how to use the Marine20 curve for calibration and how to estimate ΔR—the localized variation in the oceanic 14C levels due to regional factors which are not incorporated in the global-scale Marine20 curve. To aid understanding, illustrative worked examples are provided.

Rýzmburk Castle is one of the largest and most important medieval castles in Bohemia, documented since 1250 AD. Its North tower is assumed to be built in 1260–1300 AD. To test this assumption, the surface layers of mortar were inspected for the presence of charcoals suitable for radiocarbon dating, and 10 charcoals were found. The charcoals probably originated from wood used for lime burning. The results of radiocarbon dating using accelerator mass spectrometry agree with the historical estimation. Single post-1287 sample indicates that the building date might be refined to 1287–1300 AD.

This study applied, radiocarbon dating to charcoal and mollusk samples from Sernambetiba and Amourins archaeological sites in the Northeast region of Guanabara Bay, in the state of Rio de Janeiro, Brazil, to assess the marine radiocarbon reservoir effect (MRE) of this area, being applied for the correction of the marine samples ages. The results for this estuarine system were ΔR = –87 ± 90 14C yr and ΔR = –244 ± 70 14C yr for 3970 ± 70 14C yr BP and 2357 ± 60 14C yr BP, respectively. Based on these findings, calibrated 14C ages were calculated for Sernambetiba and Amourins shell mound sites surrounding the bay. Marine samples from the Guapi site were analyzed and only their radiocarbon ages presented because there were no paired terrestrial samples for the MRE assessment. These results are coherent with previously published values also derived from archaeological samples for the Rio de Janeiro state coastal region and contribute to the interpretation of human occupation of the region during the Holocene.

A MIni CArbon DAting System (MICADAS) has been recently installed at the Ocean University of China (OUC) mainly for determining the radiocarbon (14C) ages for marine sedimentary organic carbon. In this study, we compared the data from a series of CO2 samples measured independently by the MICADAS at OUC and ETH Zurich to assess whether the data from the OUC MICADAS meet our requirement for carbon cycle research. The measured samples covered a range of 14C ages from 1229 to 12,287 yr, and size from 5 to 162 µg C. The data from the two instruments showed a good linear relationship with only small 14C age offsets, meeting our research demands such as carbon source apportionment. Lastly, we propose that for MICADAS clients, such a cross-lab comparison of the size- and age-dependency of MICADAS using age-known samples is important for 14C data integration.