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.

McEuen Cave (AZ W:13:6 (ASM)) is a large bedrock rockshelter located within an andesitic rocky ash flow tuff/ignimbrite within the Bureau of Land Management’s Fishhooks Wilderness Area near Fort Thomas, Arizona. Exceptional preservation at the site has produced an extensive assemblage of perishable artifacts, including a tremendous quantity of cultigen remains radiocarbon dated between 3600 BP and 1250 BP. In this paper, we provide the results of a new radiocarbon dating effort aimed at identifying additional early Silverbell Interval cultigens and clarifying the intensity and persistence of Early Agricultural Period occupation. Our goal is to better understand the age and extent of early cultivation activities within this high-elevation wilderness and contextualize the remains from this site with the more thoroughly understood co-eval Early Agricultural Period villages evidenced along major riverways such as the San Pedro and Santa Cruz in southern Arizona. [Spanish language abstract: La cueva McEuen (AZ W:13:6 (ASM)) es un gran refugio rocoso de lecho rocoso ubicado dentro de una toba/ignimbrita de flujo de cenizas rocosas andesíticas dentro del área silvestre Fishhooks de la Oficina de Administración de Tierras cerca de Fort Thomas, Arizona. La preservación excepcional en el sitio ha producido un extenso conjunto de artefactos perecederos, incluyendo una tremenda cantidad de restos de cultígenos fechados por radiocarbono entre 3600 BP y 1250 BP. En este documento, proporcionamos los resultados de un nuevo esfuerzo de datación por radiocarbono destinado a identificar cultígenos adicionales del Arcaico tardío-medio y aclarar la intensidad y persistencia de la ocupación del Período Agrícola Temprano. Nuestro objetivo es comprender mejor la edad y el alcance de las actividades de cultivo tempranas dentro de este desierto de gran altitud y contextualizar los restos de este sitio con las aldeas coeval del Período Agrícola Temprano mejor entendidas evidenciadas a lo largo de las principales vías fluviales como el San Pedro y el Santa Cruz en el sur de Arizona.]

Age estimates from bomb 14C dating conflict with a well-recognized age reading protocol (grinding, polishing and staining in the sagittal plane) for otoliths of European eel (Anguilla anguilla). Proper alignment of calculated hatch years for 14C measurements taken from the earliest otolith growth—among the smallest otolith extractions to date for successful 14C analysis due to the advent of gas-AMS—was not achieved using age estimates from an accepted method. The realignment of otolith 14C values to a tropical bomb 14C reference chronology, which is most applicable to the Sargasso Sea as the natal origin of European eel, led to an increase of the original age estimates by 8 to 32 years. A maximum age of approximately 46 years was determined for the European eel specimen with the most massive otolith, of which mass is a reasonable proxy for age and was instrumental in identifying age estimate discrepancies. By extending the otolith mass-to-age relationships from this study to the most massive otoliths available from archived otoliths of Norway, an increase of up to several decades from the original otolith age estimates was discovered, leading to support for a potential lifespan of 70–100 years in the natural environment.

The use of ultrafiltration remains a subject of ongoing debate among pretreatment methods employed in radiocarbon dating of mammalian archaeological bone. However, such discourse had not previously extended to the archaeology of the Canary Islands (Spain), where detailed descriptions of laboratory processing methods for collagen purification often remain absent. Our study presents a case study involving a new set of radiocarbon dates obtained from the remains of ancient natives of Tenerife Island. For the first time in this region, we compared the results of ultrafiltered with non-ultrafiltered collagen from the same individuals, focusing on the method’s implications for dating accuracy in the Canaries. Through an examination of the cleaning protocols of ultrafilters and an assessment of the reliability of radiocarbon dating outcomes, we have found that ultrafiltration may influence the accuracy of results. However, given the additional handling required and the potential risk of contaminating the samples, its application should be carefully considered. In the context of the Canary Islands, ultrafiltration may be most relevant for samples associated with early human occupation, though further research is needed to assess its necessity across different biogeographical contexts. This communication further contributes to a broader understanding of preparation methods for radiocarbon dating bone from various environmental contexts, emphasizing the uniqueness of each case. Furthermore, we discuss the implications of our findings for archaeological research in the Canary Islands, highlighting the methodological gaps that persist in the region and underscoring the importance of ensuring the accuracy and reliability of chronological interpretations in archaeological investigations.

Sulfur stable isotope ratios (δ34S) have become increasingly common in archaeology for studying paleodiet, especially in occasions where there is a need to identify aquatic resource consumption more accurately. This is particularly relevant in the Baltic Sea region, where brackish conditions tend to mask “typical” marine carbon isotopic signals. Here we report new δ34S values for 126 human bone collagen samples which will be analyzed together with previously published data to investigate the potential of sulfur isotopes as an alternative proxy for aquatic resource consumption in historic period Estonia (ca. AD 1100‒1800). Bayesian statistical programming was used to provide quantitative dietary estimates, suggesting that the diet of the general population was predominantly terrestrial. The inclusion of δ34S as an additional dietary proxy produced generally comparable model results to the scenario that excluded δ34S. A sub-selection of samples was also radiocarbon dated and calibrated to take into account potential reservoir effects. For burials of commoners, the average contribution of 10% fish to dietary carbon does not significantly alter calibrated date ranges, even in the occasion where data on local reservoir effects is insufficient. This study has demonstrated both the potential and the pitfalls of using δ34S in this temporo-spatial context, and the new stable isotope and 14C data have shed light onto individual site-histories but also to broader cultural processes and changes that occurred during these turbulent times in this region.

The study analyses in situ CO2 mole fraction, 14CO2, and fossil based excess CO2 mole fraction (Cfoss) data at Hegyhátsál (HUN) rural monitoring station (Central Europe) supplemented by passive monitoring of 14C content of tree-rings. Through the observed period (2014–2020) we focused on revealing trends in atmospheric CO2 and 14C levels, particularly during the year of the first COVID lockdown, in comparison to the preceding five years. In addition, monthly integrated samples of atmospheric CO2 and tree-rings from the six years were subjected to 14C analysis. The passive tree-ring measurements focuses on two major urban areas (Budapest and Debrecen) in Hungary, along with the rural monitoring site. Results show a steady increase in CO2 levels at HUN between 2014 and 2020. The calculated fossil based excess CO2 concentrations for the initial year of COVID are in good agreement with the previous five-year averages both at 115 m and 10 m elevations. These results also show seasonal variations of CO2 mole fractions, peaking in winter and decreasing in summer. Tree-ring results from Debrecen show a good alignment with the results of the atmospheric monitoring station, and it does not show a significant fossil contribution in the urban background area during the vegetation periods. Tree-ring results from Budapest show a stronger fossil contribution compared to the Debrecen ones. Our atmospheric CO2 results do not show a large decrease in fossil CO2 atmospheric contribution during the first lockdown. We found that the use of this passive CO2 monitoring technique can provide a valuable tool for investigating such differences.

Ecuador is a key area in South America when it comes to understanding the economic, social and archaeological aspects of pre-Hispanic cultures in the northwestern region of the Andes. Among the most complex societies to have inhabited this territory is the so-called Manteño culture (AD ∼800–1530), which spanned across most of Ecuador’s central Pacific coast. Ongoing research at the site of Ligüiqui (Manta, Manabí) has enabled us to obtain a more complete overview of the chronological sequence of the Manteño period as well as contributing further data on the advanced stage of social development reached during the period; characterized by the hierarchical arrangement of sites, the use of extensive settlement models, and semi-circular stone fish traps (corrales). In order to understand the role played by this coastal site in the complex Manteño culture, a detailed radiocarbon study was performed in the sequence of the Ligüiqui site. In addition, using a detailed review of available Manteño settlement radiocarbon data (13 sites and 64 dates), we established a chronostratigraphic framework for the culture. Our data indicate that Ligüiqui probably acted as a supply centre for marine-origin products from the twelfth century onwards with activity peaking during the Late Manteño period. A multisite comparison using Bayesian modeling indicates an early onset of the Manteño culture in Ligüiqui around AD 700, and a general demise in most of the sites AD ∼1500 or slightly before. This culture finally collapsed before AD ∼1600 during the early Spanish colonial period. Only one site, La Libertad, shows potential evidence of having remained a Manteño settlement after that date.

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.

During the Middle Bronze Age (ca. 2000–1500 BC), the Carpathian Basin witnessed new cultural groups characterized by distinctively different pottery styles and burial rites but unified by the occupation of sites surrounded by ditches or combinations of ditches and ramparts (Bóna 1975; Kovács 1984; Sørensen and Rebay-Salisbury 2008). Due to their long occupation, many such sites are classified as multi-layered settlements (Gogâltan et al. 2014; Jaeger 2016). Despite extensive research, there remains a lack of detailed information on the absolute chronology, spatial development, and chronological relationships between settlement occupation and fortification construction (Jaeger 2016; Staniuk 2021). Most site chronologies are based on funerary ceramic typologies associated with broad temporal ranges and high uncertainties (Jaeger 2016; Staniuk 2021). Kakucs-Turján is only one of nearly 190 multilayered Middle Bronze Age (MBA) settlements in the Carpathian Basin with a tripartite division of space (Harding 2018; Jaeger 2016) (Figure 1). This, combined with its high-resolution archaeological record makes it ideal for investigating the diachronic relationship between MBA habitations and fortifications (Filatova 2020; Staniuk 2020).

While recent genomic and isotopic information show that migration has been pervasive along human history, southern Andean archaeology has largely overlooked its importance in shaping human trajectories of sociocultural change. Building on previous isotopic research that identified the presence of migrant farmers in the Uspallata Valley (Mendoza, Argentina), we present chronological and bioarchaeological results that help to characterize the timing and mode of human migrations in the southern Andes. The burials with migrants show the representation of the different age classes, including a high abundance of children, as well as both men and women, suggesting that family groups were likely involved. The Bayesian modeling of 16 direct dates for migrants indicates that these migrations started between 1210–1275 CE (median 1255 CE) and finished at 1320–1425 CE (median 1360 CE), indicating that there is nearly no overlap between the commencement of this migration phase and the southwards expansion of the Inka Empire. The model defines a diachronic process that lasted between 55 and 195 years, implying that migration to Uspallata was a multi-generational process that involved between two and eight generations (median of four generations). Our contextual, bioarchaeological and chronological evidence indicates that the conditions fostering migration to Uspallata were sustained through time, inviting to explore persisting push-pull dynamics acting during this period. 87Sr/86Sr results show that migration occurred across the daily territories of these groups and may have involved movement across social or ethnic frontiers.

Highly precise and reproducible radiocarbon (14C) measurements are regularly performed at the Heidelberg Institute for Environmental Physics, Heidelberg, Germany, in collaboration with the radiocarbon laboratory of the Curt-Engelhorn-Center Archaeometry in Mannheim, Germany. Here, we report an update of the technical details, focusing on the analysis of cold-water corals (CWC), and present an improved long-term blank value with a mean of (0.190 ± 0.064) pMC (n = 138) and excellent reproducibility of the IAEA-C2 standard with a mean of (41.15 ± 0.16) pMC (n = 75), consistent with its certified consensus value. Furthermore, 33 duplicates of the CWC 14C measurements agree within 2σ, 85% even within the 1σ range. This provides excellent conditions for accurate 14C measurements. As an application example, we present combined 230Th/U and 14C ages of a coral-bearing sediment core from the upper Mauritanian slope. The resulting ventilation age record confirms decreasing ventilation between 30 and 25 kyr BP, most likely reflecting a northward propagation of a water mass originating from the south. During the LGM, we confirm a previously hypothesized southward displacement of the Cap Verde Frontal Zone. With the onset of the deglaciation, our record documents again an advance of a southern-sourced water mass into the subtropical North Atlantic. During the Bølling-Allerød warm period, strong ventilation fluctuations possibly indicate temporal influence of southern-sourced water.

Excavation at the site of Bhagatrav yielded four layers of cultural deposits: the lowermost being the Sorath Harappan, the upper two are medieval, and layer three caps the Sorath Harappan layer. A horn-deity painted dish was found in a stratified context at the lowest level. The medieval deposit includes turquoise glazed and celadon wares, followed by an abundance of Monochrome Glazed Ware, which is otherwise known as Khambhat ware. The date of the Sorath Harappan layer of the site, the time and space of the horn-deity motif in the Harappan world, and the date of Khambhat ware have long been subjects of discussion. With the help of a series of absolute dating (radiocarbon and luminescence), this paper attempts to place the site, horn-deity motif, and the Khambhat ware in the cultural chronology of Gujarat.

Grand solar minima are periods spanning from decades to more than a century during which solar activity is unusually low. A cluster of such minima occurred during the last millennium, as evidenced by reductions in the numbers of sunspots observed and coeval increases in cosmogenic isotope production. Prior to the period of instrumental records, natural archives of such isotopes are the only resources available for detecting grand solar minima. Here, we examine the period 433–315 BCE, which saw a sustained increase in the production of the cosmogenic isotope, radiocarbon. Our new time series of radiocarbon data (Δ14C), obtained on cellulose extracted from known-age oak tree rings from Germany, reveal that the rise in production that occurred at this time was commensurate with patterns observed over recent grand solar minima. Our data also enhance, and to a degree challenge, the accuracy of the international atmospheric radiocarbon record over this period.

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.

A routine chemical procedure was developed at the Ede Hertelendi Laboratory of Environmental Studies (HEKAL), in Debrecen which can measure the dissolved organic radiocarbon content of groundwater as well as the inorganic and total fraction. The typical background of this non-purgeable dissolved organic radiocarbon preparation is 0.73 ± 0.14 percent modern carbon (pMC), using a carbon contamination correction on fossil dissolved material (potassium hydrogen phthalate) samples.

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.