A new series of 22 radiocarbon dates provides new insights on the origin and distribution of the Early Trypillian archaeological culture in modern-day Moldova and Ukraine. The paper presents data from the sites of preceding groups (5 dates), highlighting gaps in the agricultural settlement of the region, dates related to the Early Trypillia directly (14 dates) and dates from the ceramic hunter-gatherers’ sites that yielded some Early Trypillian pottery (3 dates). The results indicate that the expansion of Early Trypillia into Moldovan and Ukrainian forest-steppe took place during 47–45th centuries BCE and it was a relatively fast colonization likely spanning only 3–5 generations.

The Brazil Nut tree (Bertholletia excelsa, Lecythidaceae) is a species of considerable historical, economic and ecological importance in South America. Radiocarbon dating indicates some individuals can live from hundreds to more than 1000 years, which means they have the potential to reconstruct deep time growth patterns and their relationship to anthropogenic management or climate change from pre-colonial to present times. However, age estimates vary considerably amongst trees dated with different methods (i.e. tree-ring analysis, radiocarbon-dating, and repeated diameter measurements). Here we analyze living Brazil Nut trees growing in four distinct regions across the Brazilian Amazon using two dating methods: tree-ring counting and radiocarbon dating. Our results show that the congruence between the two methods varies amongst regions, and the highest congruence is found at the site of Tefé, Amazonas. This region features archaeological sites with anthropogenic Terra Preta soils, and is known for its long-term human forest management. This management likely enhanced light and nutrient availability, which possibly enabled the trees to grow at higher rates and form annual rings. Our findings highlight the need for better understanding of the growth of Brazil Nut trees for ecological research, but also the potential of dendrochronology for exploring climate change and human-forest interactions in the Amazon Basin.

Massive ground ice found in the Barrow Permafrost Tunnel at 3–7 m depths from the surface has been interpreted as an ice wedge and used to reconstruct early Holocene environmental changes. To better understand the development of this ground ice, we conducted radiocarbon dating for 34 samples of plant remains from the massive ground ice and underlying sediment layer. A significantly large gap in the measured radiocarbon ages (more than 24 ka) between massive ice and the underlying sediment layer throughout the tunnel profile suggested at least two possibilities. One is that the lower and older sediment layer had thrust upwards at the boundary between intruding ice wedge and adjacent sediment, and the growing ice had pushed the sediment sideways. Another is that erosional events had removed surface materials at about 12–36 ka BP (14–41 cal ka BP) before the overlaying sediment layer with massive ground ice developed. The overall distribution of radiocarbon ages from the massive ice supported the ice-wedge hypothesis as a formation mechanism, although our results showed several age inversions and large fluctuations. Dating of densely spaced samples revealed two ground-ice regions with similar ages around 11–11.5 and 10–10.5 ka BP divided by a relatively narrow region of transitional ages along the tunnel long-axis. This distribution may be explained by a possible misalignment between the sampling direction and the ice-wedge growth line or by intermittent ice growth with repeated cracking at more random locations than the classic ice-wedge growth model suggested.

This study aims to determine the chronological sequence of the collective burials in the hypogea of the prehistoric cemetery of La Beleña (Cabra, Córdoba) through Bayesian analyses of 14C dates obtained from human remains. The data from this site are not only key to grasping the phenomenon of the introduction and spread of hypogea throughout the western Mediterranean, but to gain insight into multi-stage funerary practices during the Late Neolithic/Chalcolithic. The dataset comprises 14C dates of 71 of the 79 individuals placed in five of La Beleña’s six hypogea. The findings suggest: (i) La Beleña is one of the oldest assemblages of hypogea in Iberia, (ii) that this type of collective burial spread rapidly throughout the western Mediterranean area, (iii) that La Beleña is marked by two main phases of funerary activity interspersed by brief burial surges, (iv) funerary intensity at La Beleña increased between cal BC 3400–2900 (2σ), and (v) the cemetery saw a very brief surge of burials potentially related to a catastrophic event. The results of this analysis thus shed light on the little-known chronological sequence of prehistoric hypogea or rock-cut tombs in Iberia, their spread, and their relation to other Late Neolithic collective burials in western Europe.

In the hyperarid eastern Sahara, west of the Nile River in Egypt, areas with vegetated eolian mounds have attracted people and animals because of shallow groundwater that at times of high water tables may be reached by hand digging shallow wells. An eolian phreatophytic mound with a living arak bush (Silvadora persica L.) on top, one of three known from this region of SW Egypt, provided a stratigraphic record of its growth. The geochronology of the mounds aggradation and that of a nearby tarfa mound (Tamarix nilatica Bunge) was determined by radiocarbon dating plant macrofossils within the stratigraphic succession. Eolian aggradation of the mound postdates deflation that eroded playa sediments of the Neolithic pluvial that ended ca. 5000 BP and appears to be due to a resurgence of the shallow aquifer. Subsequent deflation of the mounds is apparently due to post-1500 BP aridity. Regional vegetation is described in the Appendix I.

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.

The study of human remains can provide valuable information about aspects of past populations. Here we present an updated database consisting of 590 radiocarbon (14C) dates for human remains from Holocene South Africa before European contact. We calibrated or recalibrated all the previously published dates using the most recent calibration curve for the southern hemisphere. Each date is roughly georeferenced and plotted according to their Stone Age or Iron Age contexts, revealing the broad distribution pattern of dated Holocene human remains across South Africa—perhaps reflecting aspects of past population distribution and densities, but also underscoring historical collection practices, archaeological research focus, and preservation conditions. We use Kernel Density Estimation models to show peaks and troughs of dated remains through time, with Later Stone Age peaks at ∼5.5 ka cal BP, ∼2 ka cal BP and ∼0.5 ka cal BP, and Iron Age peaks ∼1.1 ka cal BP and ∼0.5 ka cal BP, some of which show broad correspondence to climatic data. Our data, based on dated remains only, do not provide a full reflection of past populations, and our large-scale, coarse-grained analysis cannot yet assess the reasons for the peaks in dated human remains in detail. Yet, the study provides a new resource, and a data-driven overview that highlights aspects to be explored with further contextual analyses against the available archaeological records, population histories and climatic indicators through time and across space.

The present study aims to determine the chronology of the past settlement of the different archaeological sites of the Digaru–Kolong River valley (Assam-Meghalaya Foothills), India, based on accelerator mass spectrometry (AMS) 14C dates of seven charcoal samples, five potsherds, and five sediment samples. The archaeological record of the study area consists of ground and polished stone axes and adzes, pottery, and standing or buried megaliths. The samples analyzed were excavated from test pits, and an attempt has been made to correlate the findings with the chronology of the neighboring archaeological region. A site reported in the vicinity of the study area is primarily Neolithic. However, the results from our excavations indicate a time frame for the analyzed artifacts of ca. 240 CE to 1379 CE.

This article discusses the absolute chronology of burials from the 3rd and 2nd millennia BC discovered under the mounds of three barrows in the Kordyshiv cemetery in western Ukraine. Its aim is to create a chronological model of the burials by modeling 27 AMS 14C dates obtained from 21 individuals buried in single and collective graves. Dietary analysis of stable carbon (δ13C) and nitrogen (δ15N) isotope values are presented. The Bayesian modeling of the 14C dates from the three Kordyshiv barrows revealed the extremely important role of these monuments as long-term objects used for ritual purposes. At the end of the 3rd millennium BC, the epi-Corded Ware Culture (epi-CWC) community erected a mound over the central burial in Barrow 2, then interred the graves of three additional deceased. After several hundred years Barrow 2 was reused by Komarów Culture (KC) communities from the Middle Bronze Age (MBA) who interred their deceased in the existing mound. The oldest monument with MBA burials was Barrow 3, in which the dead were buried in a two-stage sequence before and after the mid-2nd millennium BC. The youngest dated grave was Burial 1 in Barrow 1, comprising a collective burial that was interred between 1400 and 1200 BC. The additional analyses of carbon and nitrogen isotopes show significant differences in the diet of epi-CWC individuals buried in Barrow 2 from the individuals representing the KC.

Over the last decade, the field of radiocarbon analysis has been revolutionized by the discovery of single-year anomalies, because they can be used as markers of space weather events and as time anchors for exact dating. Brehm et al. (2021) recently analyzed two new anomalies, in the years 1052 CE and 1279 CE. These candidates show consecutive year Δ14C increases of 5.9‰ and 6.5‰, respectively. In this study, we measured and analyzed dendrochronologically dated oak wood samples from northern Europe spanning both these years. Our results, although statistically consistent with those presented in the original publication, show effectively no increase in Δ14C (1 and 2.5 times the measurement error, respectively). Nonetheless, we proceed to analyze our datasets with the aid of the open-source Python package ticktack. Our modeled outputs confirm that radiocarbon production barely rose above background levels across these two periods, and no event of clearly resolvable start date or duration could be detected. Additionally, we conduct the same analyses on a new sample spanning the years 531–550 CE. Here, once again, only weak evidence was obtained for any increase in radiocarbon production, and no significant annual rise was evident. The gradual increases exhibited by all three of these samples, and the ubiquity of these patterns across the calibration curve, call into question any likely cosmic event in these cases, and illustrate how challenging it will be to distinguish lower magnitude events in the radiocarbon record.

Seven accelerator mass spectrometry radiocarbon (AMS 14C) dates (7260±106∼7607±95 BP averaged 7444±103 BP) on a giant oyster shell, collected from an ancient shore of the Taipei Basin, are similar to the LSC (liquid scintillation counting) 14C age (7260±46 BP) of a grass sample inside the shell. The calibrated 14C ages of the C. gigas by Marine20 are 7490±240∼7805±230 cal BP (average 7660±96 cal BP), generally agreed with the calibrated LSC 14C ages of the grass and the oyster shell. Combined with other 14C ages of shoreline samples in the Taipei Basin, it is evident that sea level rose from 8600 to 7600 cal BP and reached a stand higher than modern sea level. During this marine transgression, the sedimentation rate along the shoreline was very high because 14C dating was not able to detect age differences for 4–5 m thick sediment sequences. Sixty-nine analyses of δ18O and δ13C from the oldest part of the shell exhibit clear seasonal cycles, with a 4-year period of growth in the 5.5-cm section. According to the δ18O values, the ancient oyster grew in a warmer-than-present shoreline environment, suggesting that the current absence of the giant oyster in Taiwan is not due to warming conditions.

Preparation of bones for radiocarbon (14C) dating is still quite a challenge for researchers. The methods are being tested and improved, to increase reliability of dating results and to verify the previous ones. In this work, a set of gelatine samples, extracted from Cervus elaphus and Cervus canadensis bones from various sites in Europe and a set of human bones from archaeological sites in Poland were subjected to retreatment using ultrafiltration in Gliwice Radiocarbon Laboratory. The tested samples represent a wide range of ages, from older than 40,000 14C years BP to modern. The prepared material was subjected to the measurement of C/N atomic ratios and 14C dating using the accelerator mass spectrometry (AMS) technique. Also, the stable isotopes (δ13C and δ15N) values were determined. In a few cases ultrafiltration allows to improve gelatine quality for long-stored samples, by increasing the %C and %N as well as decreasing C/Nat ratios. Nevertheless, this effect was not observed for majority of the samples. Remeasurements of long-term stored samples give mostly the same 14C ages for ultrafiltered ones and for those without ultrafiltration.

The chronology of the Inka Empire is poorly resolved, with most scholars utilizing a post hoc ethnohistoric reconstruction of imperial expansion as a common reference point. Radiocarbon-based analyses can now accomplish sufficient resolution for meaningful independent estimates of Inka chronology, however, and it is incumbent upon archaeologists to develop such appraisals. Here we produce a Bayesian analysis of radiocarbon data from the Upper Loa River area of northern Chile to estimate the timing of Inka incorporation of this region. In order to accurately associate samples with Inka rule, only radiocarbon dates from Inka sites without prior occupations are used (n = 34), producing a model for the onset of Inka rule of AD 1401–1437 (95% hpd) with a median date of AD 1420. This estimate is further used as a point of comparison for understanding diachronic imperial processes in the region. Site-level models of a variety of site types indicate that the Inka rapidly founded several administrative/mining bases at the onset, followed by the addition of smaller infrastructure components during a second pulse of activity near the middle of the 15th century. Date assemblages at the agricultural sites of Topaín and Paniri also indicate a decline in activity at the former and an increase in activity at the latter from early on in Inka rule. These results provide a high-resolution data point for reconstructing Inka imperial chronology, and expanding such studies will be essential to understanding processes of Inka imperialism at larger scales.

Determining calendar ages for radiocarbon dates, or ordered sequences of radiocarbon dates, that intersect with a plateau on the radiocarbon calibration curve can be problematic since, without additional prior constraints, the calendar age ranges determined will tend to spread across the plateau, yielding wide and less than useful calendar age probability densities and age ranges. Where possible, modeling analysis should seek to identify informative priors that act to restrict the otherwise poorly controlled spread of probability across plateaus. Such additional information may be available, among other sources, from the stratigraphy, the context, or the samples themselves. The recent dating of ordered sequences of radiocarbon dates on sections of branches of the same olive (Olea europaea) shrub from Therasia (southern Aegean) associated with the Minoan eruption of the Thera (Santorini) volcano (Pearson et al. 2023), which intersect with the plateau in the radiocarbon calibration curve ca. 1620–1540 BC, offers an example of the problem. A re-analysis adding some plausible informative priors offers a substantially better defined likely dating range and different conclusions. Instead of finding an inconclusive probability range “encompassing the late 17th and entire 16th century BC” followed by arguments for “indications of increased probabilities for a mid-16th century BC date for the eruption,” a re-analysis incorporating appropriate informative priors identifies the likely date range as falling between the late 17th to early 16th centuries BC.

This paper presents a detailed chronological study of the previously undisturbed burial ground of Choburak-I of the Bulan-Koby Culture in the Northern Altai using a program of comprehensive dating, including AMS 14C dating of human and animal remains (26 14C dates from 12 kurgans in total), and archaeological dating of the associated artifacts. This completely excavated cemetery contained numerous grave goods and various organic remains (anthropological and archaeozoological) critical for understanding the social and chronological dynamics of this culture during the Rouran period in Altai (second half of the 4th–first half of the 6th century CE). The results of archaeological dating, supported by the largest set of AMS 14C dates for the Bulan-Koby Culture, and further aided by Bayesian analysis, demonstrate the likely continuous existence of the necropolis within the period of 310–400 cal CE, which broadly corresponds to the beginning of the Rouran period in the history of Altai, with a maximum duration of 66 years. The presented results make it possible to consider the necropolis of Choburak-I as a chronologically defining monument of the Rouran period of Northern Altai and permit a new level of relative and absolute chronological reconstructions for archaeological sites of this region and adjacent territories at the turn of late antiquity and the early Middle Ages.

Mollusk shells are often found in archeological sites, given their great preservation potential and high value as a multipurpose resource, and they can often be the only available materials useful for radiocarbon (14C) dating. However, dates obtained from shells are often regarded as less reliable compared to those from bones, wood, or charcoals due to different factors (e.g., Isotope fractionation, reservoir effects etc.). The standard acid etching pretreatment for mollusk shells is the most used in many 14C laboratories, although another protocol known as CarDS (Carbonate Density Separation) was introduced just over a decade ago. We compare these two methods with two newly proposed methods for intracellular organic matrix extraction. We applied all four methods to samples selected from different archeological layers of the well-known Upper Paleolithic site of Vale Boi, rich in mollusk specimens throughout the stratigraphic sequence. Here we compare our results to previous dates to determine which of these pretreatment methods results in the most reliable 14C dates. Based on the results of this study, all four methods gave inconsistent ages compared to previous dates and the stratigraphic attribution.

Samples of the bones of 47 individuals from 46 Czech and Moravian ossuaries were dated by the 14C method and analyzed for the collagen isotopic composition of carbon (δ13C) and nitrogen (δ15N). Most of the data for the ages of the remains corresponded to the cooler and damper periods described over the past 1000 years. Of the studied samples, the greatest number of remains corresponded to the Spörer (1400–1570), Dalton (1790–1830) and Wolf minima (1280–1350). One sample studied falls within the Maunder minimum (1645–1715). It can be assumed that these minima are connected with a reduced production of food and fodder, that may have initiated famines, epidemics and armed conflicts. Individual climatic minima showed positive correlations between δ13C and δ15N values, indicating that the individuals studied consumed complementary plant or animal diets to different degrees. The elevated δ15N values in our studied samples compared to the skeletal compositions of the population of the La Tène period (380 – 150 BC) and Germanic inhabitants in the territory of Bohemia (5th–6th centuries AD) and Great Moravia (9th–early 10th centuries AD) might reflect the effect of greater consumption of animal proteins or the proteins of omnivorous animals and fish, which compensated for the lack of plant foodstuffs during the colder periods.

The isotopic composition of carbon and nitrogen of the bone collagen for the Spörer and Dalton minima differs from the Wolf minimum. The younger minima show higher δ15N values for a given δ13C value.

In 2021, a series of radiocarbon dates for St. George’s Rotunda in Nitrianska Blatnica (Slovakia) was published. The samples were acquired during restoration work. Based on the analysis, the authors dated the rotunda to the period of around AD 820–887, with 86% of the probability distribution lying in the period before AD 863. The chronology is based on the combined radiocarbon date 1191 ± 10 BP, which was obtained from four samples of wood fragments found in the oldest mortar layer. However, the date proposed by the authors raises concerns. The conclusions were based on a selection of samples and modeling of radiocarbon dates but put less emphasis on the results of many years of broad archaeological research on the local settlement agglomeration as well as extant historical and archaeological knowledge. The present re-analysis of the early medieval mortar and plaster samples and simple modeling corroborates the alternative hypothesis, providing us with the date 1115 ± 13 BP (cal AD 892–988 2σ). The resulting probability range is consistent with current archaeological and historical knowledge. Consequently, contrary to former conclusions, the construction of the rotunda should be dated to the period between the end of the 9th century and the end of the 10th century.

Compound-specific radiocarbon analysis (CSRA) provides the possibility to date sample material at a molecular level. N-alkanes are considered as specific compounds with high potential to CSRA. As these compounds originate from plant waxes, their radiocarbon (14C) analysis can provide valuable information about the age and origin of organic materials. This helps to reconstruct and understand environmental conditions and changes in vegetation in the past. However, CSRA has two main challenges: The small sample size of CSRA samples, making them extremely sensitive to blank effects, and the input of unknown amounts of extraneous carbon during the analytical procedure. According to the previous study from Sun and co-workers, we used different-sized aliquots of leaves Fagus sylvatica (nC27, nC29) and Festuca rubra agg (nC31, nC33) as modern standards and two commercial standards (nC26, nC28) as fossil standards for blank determination. A third commercial standard (nC27) with predetermined radiocarbon content of F14C = 0.71 (14C age of 2700 BP) serves to evaluate the blank correction. We found that the blank assessment of Sun and co-workers is also applicable to n-alkanes, with a minimum sample size of 15 µg C for dependable CSRA dates. We determined that the blank introduced during the analytical procedure has a mass of (4.1 ± 0.7) µg carrying a radiocarbon content of F14C = 0.25 ± 0.05. Applying the blank correction to a sediment sample from Lake Holzmaar (Germany) shows that all four isolated n-alkanes have similar 14C ages. However, the bulk material of the sediment and branches found in the sediment core are younger than the CSRA dates. We conclude that the disparity between the actual age of analysed organic material and the age inferred from radiocarbon results, which can occur in sediment traps due to delayed deposition, is the reason for the CSRA age.

The long-standing assumption that aboveground plant litter inputs have a substantial influence on soil organic carbon storage (SOC) and dynamics has been challenged by a new paradigm for SOC formation and persistence. We tested the importance of plant litter chemistry on SOC storage, distribution, composition, and age by comparing two highly contrasting ecosystems: an old-growth coast redwood (Sequoia sempervirens) forest, with highly aromatic litter, and an adjacent coastal prairie, with more easily decomposed litter. We hypothesized that if plant litter chemistry was the primary driver, redwood would store more and older SOC that was less microbially processed than prairie. Total soil carbon stocks to 110 cm depth were higher in prairie (35 kg C m−2) than redwood (28 kg C m−2). Radiocarbon values indicated shorter SOC residence times in redwood than prairie throughout the profile. Higher amounts of pyrogenic carbon and a higher degree of microbial processing of SOC appear to be instrumental for soil carbon storage and persistence in prairie, while differences in fine-root carbon inputs likely contribute to younger SOC in redwood. We conclude that at these sites fire residues, root inputs, and soil properties influence soil carbon dynamics to a greater degree than the properties of aboveground litter.